US3329178A - Strapping tool - Google Patents

Description

July 4, 1967 L. D. PLUNKETT 3,329,78

STRAPPING TOOL Y Filed May 24, 1965 5 Sheets-Sheet l v INVENTOR LARRY D. PLUNKETT BY jly 4, l957 1 D. PLUNKETT I3,329,.178

STRAPPING TOOL Filed May 24, 1965 5 sheets-sheet 2 July 4, 1967 .YD. PLUNKETT STRAPPING TOOL 5 Sheets-Sheet 3 Filed May 24, 1965 INVENTOR.

LARRY D.. PLUNKETT BY STRAPPING TOOL 5 Sheets-Sheet 4 Filed May 24I 1955 25e 21o 122 20o |24 202 FIGI? Kw O E T K m WN Il l., VU il [I Ill, m ml.. 5 Il Il G J D. Q 'Nl Y G P W w www PM. E m .H N 6 A L Y S H. M 4 M V B CC f i. 2 2 I K R H/A mw 0 IN 5 |I|lt| N. U 2 2/ w.. 4 M E Y 5 2 8 0 S C b f 5 e. O A 2 3 G W 2 2 2 @E wm( S V w. i.; o E A ,l O ,C o :l IJ Mo 2 B l 3 m Il [l rl 2W! n l L 4 F O 823 O Y O 22 d L2 8 MT; R W 2 N U S L. D. PLUNKETT STRAPPING TOOL July 4, 1967 5 Sheets-Sheet 5 Filed May 24, 1955 INVENTOR. LARRY D. PLUNKETT United States Patent O 3,329,178 STRAPPING TOOL Larry D. Plunkett, Algonquin, Ill., assignor to Signode Corporation, a corporation of Delaware Filed May 24, 1965, Ser. No. 458,087 1S Claims. (Cl. Mtl-93.4)

ABSTRACT OF THE DISCLOSURE A pneumatica-Hy operable heavy duty strapping tool for tensioning a loop of steel strapping about an object, applying a seal to the overlapping portions of the strapping, crimping the seal to unite such portions, and severing the loop from the source of strapping. Upon initial depression of a single control lever, the tool body which carries a tensioning Wheel shifts to a position wherein the wheel engages the strapping. At the same time a pair of seal-crimping jaws lightly engage the seal to hold it in position without crimping it while the tensioning wheel tightens the strapping loop. Upon a second depression of the lever, the jaws positively close upon the seal to crimp it, after which a shear blade severs the thus tensioned and sealed loop from the strapping source.

The present invention relates to package binding tools, commonly referred to as strapping tools, and by means of which a loop `of exible metal strapping which has been caused to encircle an article, or series of articles, is tensioned and thereafter a seal which has been positioned about the overlapping end regions of the loop is crimped or otherwise deformed to provide a seal joint, after which the feed end region of the strapping is severed to free the tensioned loop and article encircled thereby from the source of strapping.

The tool of the present invention will find particular application in applying tension to heavy duty steel strapping, i.e. strapping having a width of three-quarters of an inch or greater, and a thickness between .031 and .050 inch. Basically, the present strapping tool embodies many of the features of existing strapping tools which are designed to operate upon heavy duty strapping. For example, because of the fact that the use to which such strapping is put requires a greater degree of tensioning that may conveniently be applied by manu-al force, pneumatic power is employed to initiate the tensioning operation. Pneumatic power also is employed for eifecting'the seal crimping operation and this power is applied through opposed crimping jaws in a manner similar to that employed in connection with certain prior strapping tools. An effective pneumatically operable strap-severing method and mechanism, heretofore employed in connection with existing strapping tools, and wherein the strapping is severed in the immediate vicinity of the seal and by displacement of the seal bodily with respect to a shearing edge associated with the tool, also constitutes an adopted feature of the present strapping tool.

Apart from the adoption of the above-outlined previously used features of strapping tool operations and the employment of a more or Iless basic or standard strapping tool design which, in outward appearance at least, renders the present strapping tool similar to other known strapping tools, the present tool is possessed of numerous features of novelty which contribute toward increased efficiency of operation, both functionally and in ease of operation, as well as extending the usefulness of the tool. For example, in certain similar tools designed for the same purpose as that of the present strapping tool, the tensioning wheel which engages the feed end portion of the str-apping loop for strap feeding purposes is brought into eective engagement with the strapping by the force of gravity 3,329,178 Patented July 4, 1967 acting upon the entire tensioning assembly of which the tensioning Wheel forms a part, and including the tensioning motor. Such an expedient necessarily limits the use of a strapping tool to horizontal positioning of the tool over the package undergoing strapping and it requires the use of manual lifting force to withdraw the tensioning wheel from the strapping for purposes of strapping release. On the other hand, the strapping tool of the present invention employs pneumatically operable means for positively shifting the tensioning assembly toward and away from the strapping to bring the tensioning wheell into effective binding engagement with the latter and to Withdraw the wheel therefrom. Moreover, it maintains the tensioning wheel in such binding engagement with the strapping during the tensioning operation under pneumatic pressure. The tool thus may be used in positions other than horizontal and it may Ibe said to be capable of universal positioning during the strapping operation, even to the point of operating in an inverted position if the occasion arises.

Specifically, the strapping tool of the present invention embodies a novel control system by means of which the strap tensioning, sealing and severing operations are caused to be initiated successively, and in the order named, in a more expeditious manner than has heretofore been possible with conventional strapping tools `designed to accomplish the same over-all functions.. For example, the present strapping tool employs a single manually operable control lever which is finger-operated, as distinguished from the plural hand-operated control levers ordinarily required by similar power actuated tools, and which lever, upon an initial depression thereof, brings the tensioning assembly to an operative tensioning position with respect to the strapping and also initiates the tensioning operation and causes it to be carried out to completion. Then, upon a second depression of the same lever, the seal-crimping operation is initiated and completed and the strapping tool parts all are restored automatically to their original positions preparatory to a successive strapping operation. Apart from the initial loading of the strapping tool, two successive finger-depressions of the control lever are all that are required of the operator to complete a given strapping operation. The semiautomatic tool is therefore more nearly fully automatic than are conventional tools designed for the same purpose.

An important feature of the present invention resides in the manner in which the seal-crimping jaws are caused to close upon the seal under light spring pressure after the initial depression of the control lever to thus hold the seal in accurate register with the tensioning wheel yet without deforming the seal. This prewrapping of the crimping jaws about the seal is maintained effective during the tensioning operation. As soon as the tensioning operation is complete and the operator has depressed the control lever for the second time, the spring pressure is augmented by pneumatic pressure and the crimping jaws close still further to perform the seal-crimping operation.

Another feature of the present strapping tool resides in a novel means for holding the feed end region of the strapping loop in position against indiscriminate displacemen-t during the tensioning operation, and also holding or capturing the loose end of the strapping stock which is freed from the tool as soon as the severing operation Ihas been completed so that it will be readily accessible to the operator for subsequent loading of the tool.

Several features of novelty are associated with the previously mentioned control system for effecting semi-automatic sequential operation of the strapping tool from the initial loading thereof to the final strap severing and strapping release operations. Certain of these features are embodied in a novel pneumatic control system embodying two piston and cylinder assemblies and two valve assemblies, together with porting arrangements therefor.

Other features of novelty are embodied in certain interrelated latching means whereby the valve stems associated with the two valve assemblies are latched to hold the Valve assemblies in predetermined positions until after certain tool operations have been completed, after which they are automatically released, their release being effected under the control of the terminal movement of an element at the completion of such operations. The strapping tool is thus cyclic in its operation, portions of the tool cycle being dependent upon and being initiated by ycompletion of the next preceding portion of the tool c cle.

yStill another feature of the present strapping tool resides in a novel interlock which is provi-ded between the valve stems of the two valve assemblies to correlate their movements, the operation of such interlock being dependent upon and controlled by the operation of the aforementioned latching means.

Finally, a further feature of novelty of the present strapping tool resides in the provision of a manually operable lever and latching system by means of which the aforementioned single manually operable control lever is caused, upon successive depression thereof, to effect different valve control operations, each to the exclusion of the other. This latter lever and latching system constitutes one of the principle features of the present invention.

The provision of a strapping tool of the character briefly outlined above constitutes the principal object of the present invention.

The provision of a heavy duty power-actuated strapping tool which, despite the many functions performed by it during each tool cycle, is of relatively simple design and construction as compared to similar tools which are Vintended for the same purpose; one which is comprised of a minimum number of parts, particularly moving parts, Vand which therefore is unlikely to get out of order; one which is rugged and durable and which therefore will withstand rough usage; one which may be manufactured vat a low cost; one which is capable of ease of assembly and disassembly for purposes of inspection of parts, replacement or repair; one which is simple in its operation and which therefore does not require the use of skilled labor; one which is attractive in its appearance and pleasing in its design; and one which, otherwise, is well adapted to perform the services required of it, are further desirable features which have been borne in mind in the production 'and development of the present invention.

Other objects and advantages of the invention, not at this time enumerated, will readily suggest themselves as 44the nature of the invention is better understood.

In the accompanying five sheets of drawings forming a part of this specification, one illustrative embodiment of the invention has been shown.

In the drawings:

FIG. 1 is a side elevational view, partly in section, of a pneumatic strapping tool embodying the principles of the present invention, the tool being illustrated with the operative parts thereof in the positions which they assume when air is rst supplied to the tool and the latter is in condition for immediate use; FIG. 2 is a fragmentary detail side elevational view of a portion of the structure shown in FIG. l, the view being taken in the vicinity of the tensioning mechanism and .showing the parts in the positions which they assume during the strapping tensioning operation;

FIG. 3` is a sectional view taken substantially along the line 3-3 of FIG. 2 and showing a strapping-retaining detent mechanism employed in connection with the invention;

FIG. 4 is a rear elevational View of the strapping tool with the parts being shown in the positions which they assume during the strapping tensioning operation;

FIG. 5 is a sectional View taken substantially along the line 5--5 of FIG. 1;

FIG. 6 is a sectional view similar to FIG. 5 but showing the parts in the positions which they assume iduring the strapping tensioning operation;

FIG. 7 is a sectional view taken substantially along the line 7-7 of FIG. 1;

FIG. 8 is a pneumatic diagram, entirely schematic in its representation, showing the pneumatic control mechanism by means of which the strapping tool is operated;

FIG. 9 is a fragmentary perspective view showing certain manually operable valve control mechanism employed in connection with the present invention, the parts being shown in the position which they assume in FIG. 1; and

FIG. l0 is a fragmentary perspective view similar to FIG. 9, showing the position of the valve control mechanism upon initial depression of a certain control lever and immediately prior to initiation of the tensioning operation; and

FIG. 1l is a fragmentary perspective view similar to FIGS. 9 and 10, showing the position of the valve control mechanism upon release of the control lever and during the strapping tensioning operation.

BRIEF DESCRIPTION Referring now to the drawings in detail and in particular to FIGS. 1, 2 and 4, a pneumatic strapping tool constructed in accordance with the principles of the present invention has been designated in its entirety at 10. Briefly, the strapping tool 10 involves in its general organization three relatively movable carriage or frame assemblies including a main frame or foot assembly 12, a strapping tensioning assembly 14, and a sealing assembly 16. These three assemblies are pivoted for limited relative swinging movement about a common horizontal axis represented by the pivot pin or shaft 18. A suspension rod 20 pivoted to the sealing assembly 16 extends upwardly along one side of thetool and has an arched portion (FIG. 4) shown at 22 which is adapted to overlie the tool for supporting the same bodily from a suitable overhead hoist or support when the tool is not in operation. The rod 20 also serves as a carrying handle for the tool. When the tool is thus supported, the rod 20 extends substantially vertically as shown in full lines in FIG. 1 and, since the point of pivotal support of the tool on the rod coincides substantially with the center of gravity of the tool, the latter possesses a degree of stable equilibrium in any suspended position of the tool. When the tool is lowered upon an article undergoing strapping, the tool is supported upon the foot assembly 12 in a manner and for a purpose that will be described presently and, at this time, the supporting rod 20 may be swung to an inclined out-of-the-way position as indicated in idotted lines in FIG. 1 and in full lines in FIG. 4. Alternatively, the rod 20 may :be left in its full line vertical position to the end that the overhead hoist may continue to counterbalance a major portion of the `weight of the tool during the strapping operation, thus minimizing the possibility of crushing or otherwise damaging the article undergoing strapping. The tool 10 is capable of being used in positions other than the vertical position in which it is illustrated and the supporting rod 20 1s designed so that it may be suspended to support the tool in any desired position of inclination, such universal positioning of the tool being particularly useful in enabling the tool to be applied to irregular shaped articles or bundles.

When the tool is suspended from the rod 20 as shown 1n FIG. 1 and is in its free state, i.e. before it is connected to a source of air, the three assemblies 12, 14 and 16 assume relative positions which, in the normal operation of the tool, do not occur. As soon as the tool is supplied with air, certain valve-controlled piston move- Vments are set into operation which results in movement of the parts to the positions in which they are shown in FIG. 1. Thereafter, operation of the tool for articlestrapping purposes under the control of a manually operable lever 24 and in a manner that will be described in detail presently, effects other positional relationships of the parts whereby strap clamping, strap tensioning, seal positioning, seal crimping, strap severing and strap releasing operations automatically and progressively in the order named. Since these abnormal positions of the three assemblies 12, 14 and 16, as well as of the operative piston and valve control devices and other instrumentalities associated therewith, do not occur in the operation of the tool and otherwise perform no useful functions, they will not be described herein and reference will be made only to the operative positions of the parts.

The strapping tensioning assembly 14 has-associated therewith a pneumatically operable motor 30 which is operatively connected through a gear reduction device 32 to a rotatable strap tensioning or feed wheel 34. This wheel is designed for cooperation with a freely rotatable anvil or back-up roller 36 carried by the foot assembly 12 to clamp the feed end portion of the strapping therebetween and `draw the strap taut about the article undergoing strapping. In FIGS. 1 and 2 the manner in which the strapping S is applied to an article A and caused to pass between the tensioning wheel 34 and anvil roller 36 has been clearly illustrated. The tool is lowered into lthe vicinity of the article and the strapping S is then passed around the article A with its free end region 38 underlying the sealing assembly 16 and so that the feed end region 40 of the strapping overlaps the free end region as indicated at 42 and then passes rearwardly between the tensioning wheel 34 and anvil roller 36. The extreme end portion of the free end region 38 is turned rearwardly as at 43 so that it underlies the seal 46. The sealing assembly 16 has associated therewith a seal-retaining and seal crimping unit 44 which is effective during the tensioning operation to engage and retain a previously applied seal 46 (FIGS. 1 and 6) in encircling relationship about the overlapping portions 42 of the strapping. Subsequently, and after a predetermined degree of tension has been attained in the strapping, the unit 44 is effective to crimp the seal 46 about the overlapping portions 42. Thereafter a strap-shearing unit 48 carried by the foot assembly 12 is effective to shear the strapping S in the immediate vicinity of the seal 46, after which the strapping S is released by the tensioning wheel 34 and anvil roller 36.

As will become more readily apparent as the nature of the invention is better understood, after the tool has been supplied with air under operating pressure, the strapping tensioning assembly 14 will assume a raised position wherein its longitudinal axis is coincident with the line x-x of FIG. 1. At this time the tensioning wheel 34 will assume a retracted position remote from the anvil roller 36 so that when the tool is lowered to bring the foot assembly into contact with the article A, the feed end portion 40 may be introduced sidewise between the tensioning wheel and anvil roller. Upon an initial or first depression of the lever 24, actuation of a piston and cylinder unit 50 associated with the assembly 16 will be effective to move the tensioning assembly 14 bodily as a unit to a lowered position wherein its longitudinal axis is coincident with the line y-y of FIGS. 1 and 2 to engage the strappjing between the tensioning Wheel 34 and anvil roller 36, and at the same time move the foot assembly 12 including the strap-shearing unit 48 to the position wherein it is shown in FIG. 2 and wherein the shearing unit 48 is in close proximity to and in register with the seal crimping unit 44. As soon as the two assemblies 14 and 12 have thus moved to the positions wherein they are shown in FIG. 2, the tensioning or feed wheel becomes efective to tension the strapping about the article. When the strapping has attained a predetermined degree of tension, the lever 24 is again depressed and actuation of a piston and cylinder unit S2 (FIGS. 5 and 6) is initiated to effect the seal crimping operation and such operation is followed automatically by actuation of the shearing unit 48 to Sever the strapping S in the immediate vicinity of the crimped seal 46. As soon as the severing operation has been completed, the tool is automatically operable to restore the assemblies 12, 14 and 16 to their original positions as shown in FIG. 1, the unit 44 serving to release the seal 46, and the tensioning wheel 34 and anvil roller 36 serving to release the strapping S, thus freeing the tool.

THE FOOT ASSEMBLY The foot assembly 12, although of appreciably smaller proportions than the assemblies 14 and 16, may for facility of description be regarded as the main frame of the tool 10 inasmuch as during the actual strapping operation it seats squarely upon the article undergoing strapping and affords reaction for the movements of the two other assemblies. This assembly 12 is comprise-d of a casting which is generally L-shape in transverse cross section and which provides a laterally extending horizontal foot proper 60, the underneath surface of which is formed with a shallow channel 62 (FIGS. 1 and 2) which guides or centers the strapping S during the tensioning operation. The rear end of the foot casting is bifurcated as shown at 64 in FIG. 4 and the previously mentioned anvil roller 36 is rotatably supported upon a transverse shaft 66 which extends across the bifurcations. The foot casting further includes a vertically extending wall 68 the upper region of which is formed with a lateral boss 70 through which the pivot pin or shaft 18 extends. A

raised shoulder-forming rib 72 (FIGS. 1 and 4) on the wall 68 is designed for engagement with a pin 74 carried by the sealing assembly and limits the extent of swinging movement of the sealing assembly in one direction with respect -to the foot casting. The shearing unit 48 is removably Imounted by means of clamping bolts 76 on the forward region of the foot casting and the front side of this unit is engageable with the rear side of the seal retaining and crimping unit to limit the extent of swinging movement of the latter unit with respect to the foot casting in the other direction.

Swinging movements of the tensioning assembly 14 in opposite directions with respect to the foot casting 12 is limited by the provision of an elongated clearance slot 78 (FIG. 2) formed in the vertical wall 68, one end 80 of the slot being engageable with a tensioning wheel supporting shaft 82 associated with the assembly 14 to limit the raised inoperative position of the assembly.

An adjustable set screw 86 opposes a downwardly facing shoulder 88 provided on a radially disposed protuberance 90 formed on the gear reduction device 32 and is designed for engagement with the shoulder to prevent direct engagement between the tensioning wheel 34 and the anvil roller 36 when there is no strapping in the tool.

The strap-retaining detent device A lateral shelf portion 9'2 formed on the vertical wall 68 carries a spring pressed detent ball 93 which is in register with a laterally projecting pin 94 immediately below the ball, the ball and pin constituting a friction grip arrangement for the strapping S as it emerges from between the tensioning wheel 34 and anvil roller 36 during the tensioning operation, the arrangement being provided principally to capture the feed end portion of the strapping at the time of strap severing and retain it so that it is readily :accessible to the operator at the time that the severing operation transforms it into the free end portion of the next length of strapping to be applied to a subsequent article to be strapped. The detent arrangement also constitutes a safety feature to prevent the hazard of loose spring tensioned or spring flexed strapping in the vicinity of tool operations.

a The shearing unit The previously mentioned shearing unit 48 is of conventional construction .and is comprised of a generally H-shaped bracket 95 secured by means of the bolts 76 to the foot casting and having slotted side walls 96 which slidably retain therebetween a shear blade or cutter 97. The cutter 97 is yieldingly biased by a spring 98 to a raised retracted position and is adapted to be forced downwardly in the performance of its strap-severing stroke by engagement with a moving element associated with the seal retaining and crimping unit 44 after the crimping operation has been completed, all in a manner that will be set forth subsequently.

THE TENS'IONING ASSEMBLY The specific details of the pneumatically operable motor 30 and of the gear reduction device 32 which, in the main, constitute the tensioning assembly 14 have not been illustrated herein inasmuch as they form no part of the present invention. Any suitable type of air-operated motor and associated gear reduction device may `be employed. The housings for these two instrumentalities are suitably bolted or otherwise connected together and provide the aforementioned elongated tensioning assembly 14, the longitudinal axis of which is shiftable between the positions x-x and y-y of FIG. l as the assembly moves between its raised inoperative and its lowered operative positions. As best seen in FIGS. 1 and 4, the housing for the pneumatic motor 30 is provided with an adjustable air restriction elbow fitting 100 by means of which the motor may be connected to a second elbow fitting 102 associated with the previously mentioned piston and cylinder assernbly 52 and forming a part of the sealing :assembly 16. -A flexible conduit 104 extends between the two elbow fittings 100 and 1012.

As previously stated, the pivot pin or shaft 18 constitutes the common pivotal support for the three assemblies 12, 14 and 16. Insofar asY the assembly 14 is concerned, the upper forward region of the gear reduction device 32 iixedly receives the shaft 18 so that swinging movements of the assembly 14 is accompanied by rocking movement of the shaft 18. A link 110 which may be regarded as a part of the tensioning assembly 14 since it moves bodily with this assembly, has its proximate end 4connected to the shaft 18 and its distal end connected to the shaft 82 which supports the tensioning wheel 34. The link 110, in effect, constitutes a crank arm by means of which rocking movements of the assembly 14 on the foot assembly 12 may be effected under the control of a connecting or positioning link 112. The lower end of the link 112 is connected to a pin 114 provided in the medial regions of the link 110 while the upper end of the link 112 is connected to a plunger 116 carried by a piston l117 mounted for reciprocation in a cylinder assembly 50. This latter assembly thus serves to effect limited swinging movement of the link 110 to, in turn cause shifting movement of the assembly 14 bodily as a unit all in a manner and for a purpose that will be set forth subsequently. The previously mentioned shoulder-forming protuberance 90 is formed on the housing of the gear reduction device 62. An upstanding lug 119-(see also FIGS. 9, 10 and ll) also formed on the housing, carries a cross-pin 121 which provides a trunnion support for the operating lever 24.

THE SEALING ASSEMBLY Framework The sealing assembly 16 involves in its general organization a relatively large casting providing an upper cup-shaped housing 120 the upper open rim of which is closed by a closure head or plate 122 secured in position by bolts 124. The housing 120 is internally compartmented to provide the cylinder 126 of the previously mentioned piston and cylinder unit 52, as well as to provide the cylinder 118 associated with the previously mentioned 8 Ipiston and cylinder unit 50 (FIGS. l and 7), and also a pair of valve chambers 1132 and 134 (FIG. 7).

The housing is provided with a lbottom wall 140 from which there extends downwardly a pair of spaced .apart ears 142 (FIGS. l, 2 and 4), the previously mentioned pivot pin or shaft 18 extending transversely between the ears and serving as a pivotal support of the assembly 16 as a whole. The suspension rod 20 also is pivotallysupported by the ears 142. A pair of spaced apart ribs 144 FIGS. 1, 2, 5 and 6) also depend from the bottom wall and serve as a support for the previously mentioned seal crimping unit 44.

The seal crimping unit The seal crimping unit 44 involves in its general organization a pair of plates and 152 (FIG. 2) which are secured to the ribs'144 by means of machine screws 154. A vertical guide slot 156 (FIG. 5) is formed in the plate 152 and establishes a guideway for the vertical reciprocating movements of a cross pin 158 which is secured in a Icrosshead 160 fixedly carried at the lower end of a plunger 4162 associated with a piston 164 mounted for reciprocation in the cylinder 1,26. A notcher block 166 positioned between the plates 150 and 152 is supported on cross pins 168 and dual jaw members 170 having seal-retaining and crimping jaws proper 172 at their lower ends are pivoted on the pins 168 and are pivotally connected at their upper ends to the lower ends of spreader links 174. The upper ends of the spreader links 174 are pivotally connected to the cross pin 158.

The specific details of the jaw mechanism associated with the seal crimping unit 44 and including the jaw melmbers 170, spreader links 174, crosshead 160, guide plate 1'52 and notcher block 166 are more or less of conventional design and no claim is made herein to any novelty associated with the same. A similar jaw mechanism has been shown and described in United States patent to Meier, Patent No. 3,150,694, granted on Sept. 29, 1964, and entitled Strapping Tool. Reference may be had to the above-mentioned patent for a full understanding of the nature and operation of such a jaw mechanism. For purposes of description herein it is deemed sufficient to point out, briefly, that the crimping operation is effected when the plunger 162 moves downwardly in the cylinder 126, at which Ytime the spreader links 174 force the upper ends -of the jaw members outwardly so that the lower ends of these members including the crimping jaws proper 172 close inwardly upon the seal 46 and force the latter against the notcher block 166, thus tightening and crimping the seal about the overlapping regions 42 (FIG. 1) of the strapping S in the usual manner.

As is the case in connection with the crimping unit of the aforementioned patent to Meier, the crimping unit 44 and shearing unit 48 cooperate with each other in effecting shearing of the excess strapping along and by the rear edge of the seal 46. Accordingly, the pin 158 projects completely through the guide slot 156 (FIGS. 2 and 5) as indicated at 180 and this projecting portion is designed for engagement with the shear blade or cutter 97 at such time as the piston 164 is at the bottom of the cylinder 126 and the pin 158 is at the bottom of its stroke. Upon depression of the cutter 97 by the projecting portion of the pin 158, the cutter is forced downwardly against the yielding action of the spring 98, thus engaging and depressing the adjacent edge of the seal 46 and causing relative movement between the excess portion of the strap and the relatively sharp forward edge of the foot proper 60 so that the strap is severed along the rear edge of the seal, all in the manner set forth in the above-mentioned patent to Meier.

It is to be noted at this point, however, that while the details of the seal crimping and strap shearing units 44 and 48, and the manner in which they cooperate with each other are, in general, similar to the corresponding units shown and described in the Meier patent, the control mechanism by means of which the units 44 and 48 are actuated differs widely from the control mechanism of such patent. As will be pointed out in greater detail presently, the piston 164 is normally and yieldingly biased downwardly in the cylinder 126 by means of a helical involute compression spring 182 (FIGS. 5 and 6) so that when the lower region of the cylinder is in communication with the atmosphere and no air is supplied to the upper region thereof, the piston is forced downwardly solely under the influence of the spring 182, thus moving the crimping jaws proper 172 into holding engagement with the seal 46 under insufficient pressure to effect the crimping operation. The seal is thus held in a position of register with the tensioning wheel 34 and anvil roller 36 during the strap tensioning operation. The jaws 172 may thus be said to be prewrapped about the seal 46 for seal-aligning and holding purposes, this prewrap condition constituting one of the principal features of the present invention. Subsequently, at a point later in the tool cycle, air under full line pressure is applied to the upper region of the cylinder 126 to forcibly drive the piston 164 downwardly, thus applying full power to the crimping jaws 172 and effecting the crimping operation.

THE PNEUMATIC CONTROL INSTRUMENTALITIES The valve mechanism and valve porting Briefly, the operation of the pneumatic strapping tool 10 is effected under the control of two valve assemblies 200 and 202 which are disposed in the previously mentioned valve chambers 132 and 134 respectively (FIG. 7). Actuation of the two valve assemblies -is effected under the control of an external compound lever and latch mechanism which has been designated in its entirety at 204 and illustrated in detail in FIGS. 9, l and l1, this latter system including the previously mentioned manually operable lever 24.

The valve assembly 200 includes a spool-type valve body 206 (FIG. 7) which is vertically slidable in a composite valve cage 208 and normally is urged by means of a spring 210 to the lowered position in which it is shown in FIG. 7. The valve body 206 is formed with a depending valve stern 212 (see also FIGS. 9, 10 and l1) which projects outwardly of the housing 120 through an exhaust port 214 and is designed for engagement with an element of the external lever and latch system 204 as will be described presently.

The valve assembly 202 includes a spool-type valve body 216 which is vertically slidable in a valve cage 218 and is normally urged by means of a spring 220 to the lowered position of FIG. 7. A valve stem 222 projects downwardly from the valve body 216 out of the housing 120 and is designed for engagement with another element of the lever and latch system 204 as also will be described subsequently.

Referring now to FIGS. 1, 7 and 8, air is supplied to the tool 10 through a flexible conduit 240 and quickrelease fitting 242 carried -by an elbow 244 from whence it is supplied to the valve chamber 132 through an internal passage 246 (FIG. 7) provided in the housing 120. It is to be noted at this point that in FIG. 8, wherein the pneumatic circuitry for the tool 10 has been shown, dotted lines are employed to designate external air lines while full lines have been employed to designate internal air passages within the housing 120. A dotted rectangle designated at 120 represents the housing.

An internal passage 248 establishes communication between the valve chamber 132 and the cylinder 12,6 (see also FIG. A second internal passage 250 establishes communication between the valve chamber 132 and the cylinder 118. A third internal passage 252 establishes communication between the valve chambers 132 and 134. A fourth internal passage 254 establishes communication between the valve chamber 132 and the cylinder 118. A fifth internal passage 255 establishes cornmunication between the valve chamber 134 and the cylinder 126. An exhaust passage 256 connects the valve chamber 134 to the atmosphere. Finally, the previously mentioned flexible air line 104 is connected through the elbow fitting 102 to an internal passage 258 leading to the valve chamber 134.

The manually operable lever and latching mechanism The previously mentioned lever and latch mechanism 204 of FIGS. 9, l() and 11 includes the manually depressible lever 24 and this mechanism is so designed thatupon an initial depression and release of the lever 24 the valve stem 212 will become elevated and latched in its raised position, at which time the tensioning assembly 14 will shift from its raised position represented by the axis x--x to its lowered position represented by the axis y-y while at the same time the tensioning motor 30 will be energized. Then, upon a subsequent depression of the lever 24, the valve stem 222 will become elevated and latched in its raised position, at which time the seal crimping unit 44 will become effective to crimp the prepositioned seal 46 about the overlapping portions of the strapping S and the shearing unit 48 will severe the strapping in the immediate vicinity of the seal 46. As soon as the strap-severing operation has been completed, means automatically become effective to release the latching devices for both valve stems 212 and 222 to the end that all the strapping tool parts will be restored to their initial position preparatory to the performance of a subsequent strapping operation.v

Accordingly, the valve stem is designed for engagement with a lateral projection 260 on a secondary lever 262 which is pivoted at one end to a depending lug 264 and which carries a roller 266 at `its distal end. The lever 24 is pivoted medially of its ends on the pin 121 and the rear end 267 of the lever 24 constitutes a finger pad which is designed to be depressed for lever-actuating purposes. The roller 266 overlies the forward end of the lever 24 and rides thereon so that upon depression of the rear end of the lever 24, the roller 266, and consequently the secondary lever 262, is moved to an elevated position wherein the lateral projection 260 engages and raises the valve stem 212 and consequently the valve body 206, at a predetermined time in the tool cycle `as will also be described presently.

The valve stem 222 is designed for engagement with a spring-pressed `dog 268 pivotally mounted on the lever 24. The dog 268 is yieldingly biased by a spring 270 against a pin 272 to a normal position wherein it projects laterally of the lever 24 and underlies the valve stem 222 as shown in FIG. l1 when the tensioning assembly 14 is in its lowered position coincident with the axis yy. Thus, when the assembly 14 is in such lowered position and the rear end 267 of the lever 24 is manually depressed, the 'dog 268 will engage the valve stem 222 .and raise the same, thus elevating the valve body 216. When the tensioning assembly 14 is in its elevated position coincident with the axis x-x as shown in FIG. 9, the dog 268 will be out of register with the valve stern 222 and actuation of the lever 24 will cause raising of the valve stem 212 as previously described but will fail to cause raising of the valve stem 222.

The valve stem latching device As best seen in FIGS. 7 and 8, means are provided for latching the valve stem 212 in its elevated position after initial raising of this stem by the laternal projection 260 on the lever 24. This means comprises a latch shaft 280 having a first half-moon extension 282 designed for latching engagement with a shoulder 284 provided on the valve stem 212, such engagement taking place when the valve stem is initially moved to its raised position. The latch shaft 280 projects outwardly of the housing as shown in FIG. 4, and is yieldingly biased by a spring 290 into latching position. A second half-moon extension 292 (FIGS. 5 and 6) is provided on the latch shaft 280 and normally assumes a position adjacent the bottom wall 140 of the housing 120 and in the path of movement of the piston 164 so that at such time as the piston has fully descended in the cylinder 126, this latter extension 292 will be engaged by the underneath side of the piston and the latch shaft rocked against the action of the spring 290 to valve stem-releasing position. A manually operable trip nger 294 (FIG. 4) is provided on the outwardly projecting portion of the latch shaft 280 and may be employed to release the latched valve stem 212 at such time as a jam or other malfunctioning of the strapping tool takes place as will be described subsequently.

The valve stem interlock Still referring to FIGS. 7 and 8, an interlock connection between the valve stems 212 and 222 s provided whereby upon movement of the valve stem 222 to its raised position the same will become effectively latched in such position and will remain thus latched until such time as the previously raised valve stem 212 is released by half-moon extension 282 on the latch shaft 280. Accordingly, a latch arm 300 (FIGS. 7 and 9) is pivoted for swinging movement in a horizontal plane about the vertical axis of a retaining bolt 302 and is disposed substantially midway between the valve stems 212 and 222, the arm underlying the housing 120. A spring 304 biases the arm into cooperating engagement with the valve stern 212, the effective diameter of the latter stem at its point of contact with the latch arm determining the position of the arm. The valve stem 212 is formed with a reduced section 306 at its extreme lower end and this reduced section is connected to the main body portion of the valve stem by a frusto-conical section 308. When the valve stem 212 is in its fully lowered position, the adjacent end region of the latch arm 300 bears yagainst the main body portion of the valve stem 212 while the opposite end region is maintained clear of the valve stem 222. When the valve stem 212 is in its raised position, the adjacent end of the latch arm 300 moves inwardly toward the reduced section 306 and the opposite end region of the arm is biased against the valve stem 222 under the influence 0f the spring 304. This condition permits the latch arm 300 to move beneath a downwardly facing annular shoulder 310 on the valve stem 222 and thus latch the latter stem in its raised position. At such time as the valve stem 212 is released by `the latching extension 282 of the latch shaft 280 as previously described, the adjacent end of the latching lever 300 will ride outwardly on the frusto-conical section 308 of the valve stem 212 during descent of the latter and return to its position on the main body portion of the valve stem, thus causing the opposite end of the lever 300 to move away from the valve stem 222 and release the latter for downward movement under the influence of the spring 220.

OPERATION OF THE STRAPPING TOOL Before describing the operation of the strapping tool 10 in detail, it is deemed pertinent in the interests of clarity to ascribe functional designations to two valve assemblies 132 and 134 and to the two piston and cylinder assemblies 50 and 52. These functional designations have been applied in the form of labelling in FIG. 8. Inasmuch `as descent of the piston 164, either under the influence of the spring 182 or of pneumatic pressure, serves to effect closure of the jaws proper 172 against the seal 46, the piston and cylinder assembly 52 has been designated as -the sealing cylinder. Inasmuch as movement of the piston 117 serves to position the tensioning assembly 14 with respect to the sealing assembly 16, the piston and cylinder assembly 50 has been designated as the positioning cylinder. The valve assembly 132 has been designated as the tensioning valve inasmuch as its operation controls the operation of the tensioning motor 30. Finally, the

valve assembly 134 has been designated as the crimping valve inasmuch as its operation controls the application of pneumatic pressure to -the upper end of the cylinder 126 for the purpose of forcibly driving the piston 164 downwardly to effect the seal crimping operation.

In the operation of the strapping tool 10, the tool may be suspended from an overhead hoist or adjustable tool balancing support by means of the suspension rod 20, the rod being designed to maintain the tool at various universal inclinations other than the vertical position in which it is shown in the drawings. An appreciable amount of the total -weight of the tool is thus supported to the end that the danger of damaging the article A undergoing strapping will be minimized. The tool is then manipulated to bring the foot proper 60 to a position wherein its underneath surface bears against the article A as shown in FIG. l. Prior to such manipulation of the tool 10, the strapping S is passed around the article A and fed through a seal 46 in such a manner that the feed end region 40 overlies the free end region 38 as it passes through the seal. The extreme free end portion 43 of the free end region is turned rearwardly and underlies the seal 46 so that this portion of the strapping is anchored in position between the seal and article A during the tensioning operation. When the tool is brought into position against the article A, the guide channel 62 in the foot proper 60 becomes centered over the strapping. The feed end portion of the strapping is caused to pass over the foot proper 60 and enter between the detent ball 93 and pin 94 as previously described and from thence the strapping S passes to a suitable source of strapping such as a strapping coil or the like. Manual tensioning may be resorted to until all looseness in the encircling strap has been taken up and the strap `assumes its approximate final position with respect to the article.

It will be understood that prior to application of the strapping tool 10 to the article A, the flexible conduit 240 will have been applied to the quick-release fitting 242 so that the strapping tool will be supplied with air, the air entering the valve chamber 132 through the passage 246 (FIG. 7) and flowing through the valve cage 208 to the passage 248 from whence it enters the cylinder 126 (FIG. 5) in the lower regions thereof and maintains the piston 164 in its uppermost position against the action of the spring 182. With the piston 164 thus elevated, the seal crimping unit 44 assumes the position in which it is shown in FIG. l with the crimping jaws proper 172 in their fully open position. At the same time, `air leaves the valve chamber 132 through the passage 250 and enters the cylinder 118 below the piston 117, thus elevating the piston and causing the tensioning lassembly 14 to assume the position wherein it is shown in FIG. l with its axis coincident with the line x-x. At this time the tensioning or feed wheel 34 will be out of effective engagement with the anvil or back-up roller 36 to facilitate loading of the tool in the manner previously described.

After the strapping tool 10 has been loaded with the strapping S, the lever 24 is initially depressed, at which time the pivoted dog 268 (FIG. 9) will be out of register with the lower end of the'valve stern 222 so that raising of the forward end of the lever 24 will fail to effect engagement of this valve stem by the dog 268. However, the lateral projection 260 on the secondary lever 262 which, at this time is in register with the valve stem 212, will engage this valve stem and raise the same as the roller 266 is forced upwardly by the forward end of the lever 24. This movement of the valve stem 212 causes the valve body 206 (FIG. 7) to become elevated and the half-moon extension 282 of the latch shaft 280 will engage the shoulder 284 on the valve stem 212 and maintain the valve body 206 in its raised position. As the valve stem 212 thus moves upwardly, the adjacent end of the latch arm 300 will ride inwardly on the frustoconical section 308 of the valve stem and the opposite I3 end of the arm will engage the valve stem 222 and yieldingly bear thereagainst under the influence of the spring 304 (FIG. 7).

With the valve body 206 thus raised, the passages 248 and 250 will exhaust to the atmosphere through the exhaust port 214. At the same time air will feed through the passage 254 and enter the cylinder 118 above the piston 117 to force the latter downwardly and cause shifting of the tensioning unit 14 bodily as a unit so that its axis will coincide with the line y-y of FIGS. 1 and l1, thus bringing the tensioning wheel 34 into cooperation with the anvil or back-up roller 36 for strapping engaging purposes. Air also will at this time pass through the passage 252, enter the valve chamber 134, and be conducted through the passage 258, elbow fitting 102 and flexible line 104 to the tensioning motor 30 which will thus be energized to cause rotation of the tensioning wheel in a tensioning direction to draw the strapping S about the article A in the usual manner of strap tensioning.

Inasmuch as at this time the passage 248 (FIGS. and 7) as in communication with the atmosphere through the exhaust port 214, the spring 182 will force the piston 164 downwardly in the cylinder 126 to close the crimping jaws 172 about the seal 46 which has been previously positioned about the overlapping portions of the strapping, as shown in FIG. 6. The force of the spring 182 is insufficient to crush or crimp the seal 46 and is sufficient merely to preposition the seal and hold it in register with the shearing unit 48 which has now moved into operative register and cooperation with the sealing unit 44 as previously described and as shown in FIG. 2. This seal-engaging or prewrap condition is maintained during the entire tensioning operation and until such time as the lever 24 is again depressed for seal crimping purposes as will now be fully described.

It is to be noted at this point that during movement of the tensioning assembly 14 from its raised to its lowered position as previously described, the pivoted dog 268 will engage and slide upon the valve stem 222 and finally move beneath this latter valve stem at such time as the tensioning assembly 14 attains its lowermost position coincident with the line y--y. At such time as the tensioning operation has been completed, and as evidenced by stalling of the tensioning motor 30, the operator will again depress the lever 24. The pivoted dog 268 will at this time engage the valve stem 222 and raise the same, thus raising the valve body 216 within the valve chamber 134 (FIG. 7). At this time the adjacent end of the latch arm 300 will move beneath the shoulder 310 on the valve stem 222 and latch the stem and valve body in an elevated position against the action of the spring 220.

With the valve body 216 thus raised, air issuing from the passage 252 will flow through the passage 255 (FIGS. 5 and 7) and enter the cylinder 126 above the piston 164, thus driving the latter downwardly and effecting the seal crimping operation as the crimping jaws proper 172 forcibly close upon the seal 46. This downward power stroke of the piston 164 not only effects the seal crimping operation but it also effects operation of the shearing unit 48 due to the fact that the extension 180 of the cross pin 158 engages the shear blade or cutter 97 at the bottom of its stroke and depresses the seal 46 so that the strapping S is sheared against the forward edge of the foot proper 60 in the manner previously set forth and as fully described in the above-mentioned patent to Meier No. 3,150,694.

At such time as the piston 164 reaches the bottom of its power stroke, the underneath side of the piston engages the half-moon extension 292 (FIG. 5) on the latch shaft 280, thus rotating the shaft 280 and causing the halfmoon extension 282 (FIGS. 7 and 8) to release the shoulder 284 on the valve stem 212 and allowing the valve body 206 and stem 212 to move downwardly under the inliuence of the spring 210. Such downward movement of the stem 212 causes the adjacent end of the latch arm 300 to ride outwardly on the frusto-conical section 308 of the valve stem 212, thus withdrawing the opposite end of the latch arm 300 from the valve stern 222 and allowing this latter stem, together with its associated valve body, to move downwardly.

With b-oth valve bodies 206 and 216 now in their lowered positions in thevalve chambers 132 and 134 respectively, air is exhausted from the passage 255 (FIGS. 5 and 7) to the atmosphere through the valve chamber 134 and `from thence through the exhaust passage 256. At the same time air is exhausted from the upper end of the cylinder 118, through the internal passage 254, valve chamber 132, passage 252, valve chamber 134, passage 258, elbow fitting 102 and flexible conduit 104 to the tensioning motor 30, from whence it escapes through the usual exhaust ports (not shown) associated with the motor. At this time, air under full line pressure is restored to the cylinder 126 below the piston 164 from the port 248 as previously described, thus forcing the piston 164 upwardly against the action of the spring 182. Also, air under full line pressure is applied to the cylinder 118 below the piston 117 from the port 250 as also previously described, thus causing the tensioning assembly 14 to return to its position wherein its longitudinal axis is coincident with the line x-x. The various strapping tool instrumentalities are thus restored to their original position as shown in FIG. 1 preparatory to the next strapping operation.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification `as various changes in the details of construction may be resorted to without departing from the spirit of the invention. Therefore, only insofar as the invention has particularly been pointed out in the accompanying claims is the sanne to be limited.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a pneumatically operable strapping tool for 'tensioning a loop of strapping about an article, said loop having overlapping free end and feed end portions threaded through a seal, and for thereafter crimping the seal about said overlapping portions, a frame ladapted to rest upon the article, a strap tensioning member supported on the frame, a sealing assembly supported on the frame and including a pair of seal-positioning and sealcrimping jaws movable from an open seal-releasing position through an intermediate seal-retaining position to a fully closed seal-crimping position and vice versa, a cylinder supported on the sealing assembly, a piston slidable in said cylinder and operatively connected to said sealing jaws, said piston being movable between a retracted position wherein said jaws are in their sealreleasing position and a fully advanced position wherein the jaws are in their seal-crimping position, spring means yieldingly biasing said piston toward its fully advanced position to cause said jaws to engage the seal under pressure sutiicient only to engage and maintain the seal positioned with respect to the tensioning member but insucient to crimp the seal, and manually operable Valve means for supplying air to said cylinder to augment the action of said spring biasing means and force the piston to its fully advanced position.

2. In a pneumatically operable strapping tool for tensioning a loop of strapping about an article, said loop having overlapping free end and feed end portions threaded through a seal, and for thereafter crimping the seal about said overlapping portions, a frame adapted to rest upon the article, a strap tensioning Wheel supported on the frame, a sealing assembly supported on the frame and including a pair of seal-positioning and seal-crimping jaws movable from an open seal-releasing position through an intermediate seal-retaining position to a fully closed seal-crimping position and vice versa, a cylinder l supported on the sealing assembly, a piston slidable in said cylinder and operatively connected to said sealing jaws, said piston being movable between a retracted position wherein said jaws are in their seal-releasing position and a fully advanced position wherein the jaws are in their seal-crimping position, spring means yieldingly biasing said piston toward its fully advanced position to cause said jaws to engage the seal under pressure sufficient only to engage and maintain the seal positioned with respect to the tensioning wheel but insufficient to crimp the seal, and manually operable valve means for selectively supplying air to the opposite ends of said cylinder to maintain the piston in its retracted position against the action of said spring biasing means and to augment the action of said spring biasing means and force the piston to its fully advanced position respectively.

3. In a pneumatically operable strapping tool for tensioning a loop of strapping about an article, said loop 'having overlapping free end and feed end portions threaded through a seal, and for thereafter crimping the seal about said overlapping portions, a frame adapted to rest upon the article, a strap tensioning member supported on the frame, a sealing assembly supported on the frame and including a pair of seal-positioning and seal-crimping jaws movable from an open seal-releasing position through an intermediate seal-retaining position to a fully closed seal-crimping position and vice versa, a cylinder supported on the sealing assembly, a piston slidable in said cylinder and operatively connected to said sealing jaws, said piston being movable between a retracted position wherein said jaws are in their seal-releasing position and a fully advanced position wherein the jaws are in their seal-crimping position, spring means yieldingly biasing said piston toward its fully advanced position to cause said jaws to engage the seal under pressure sufficient only to engage and maintain the seal positioned with respect to the tensioning member but insufficient to crimp the seal, a manually operable control valve including a valve body effective in a first position i to supply air to one end of said cylinder to maintain the piston in its retracted position against the action of said spring means and effective in a second position to supply air to the other end of the cylinder to augment the action of said spring means and force the piston to its fully advanced position, spring means yieldingly urging said valve body to its first position, latch means autor matically effective upon movement of the valve body to its second position to latch the same in such position, and means automatically operable upon movement of the piston to its fully advanced position to release said latch means for return of the valve body to its first position under the influence of said spring means.

4. In a pneumatically operable strapping tool for tensioning a loop of strapping about an article, said loop having overlapping free end and feed end portions threaded through a seal, and for thereafter crimping said seal about the overlapping portions, a main frame adapted to rest upon the article, a strap-tensioning member supported on the main frame, a sealing assembly pivotally supported on the main frame and including a pair of seal-retaining and seal-crimping jaws movable from an open seal-releasing position, through an intermediate position wherein the jaws straddle and engage the seal in holding relationship, to a fully closed sealcrimping position and vice versa, said sealing assembly being movable between a retracted position wherein said jaws are out of register with the seal and an advanced position wherein the jaws are in register with the seal, a first piston and cylinder unit effective between the sealing assembly and main frame to move the sealing assembly between its retracted and advanced positions, a second piston and cylinder unit carried by the sealing assembly and effective to actuate said jaws, spring means normally biasing said second piston and cylinder assembly to move said jaws toward their intermediate posi- Cil tion, and manually operable valve means effective in a first position to supply air to said first and second piston and cylinder assemblies to maintain said sealing assembly in its retracted position and to maintain the jaws in their open position against the action of said spring means, effective in a second position to relieve said second piston and cylinder assembly of air and cause said jaws to move to their intermediate seal-retaining position, and effective in a third position to supply air to said second piston and cylinder assembly to move said jaws to their fully closed seal-crimping position.

5. In a pneumatically operable strapping tool for tensioning a loop of strapping about an article, said loop having overlapping free end and feed end portions threaded through a seal, and for thereafter crimping the seal about said overlapping portions, a foot assembly including a foot proper adapted to rest upon the article and having an anvil member adapted to underlie said feed end portion, a tensioning assembly including a rotatable strap-tensioning wheel and a ldrive motor operatively connected thereto, a seal-crimping sealing assembly including a housing and a `crimping unit carried thereby, said crimping unit including seal-retaining and seal-crimping jaws movable from an open seal-releasing position through an intermediate seal-retaining position to a fully closed seal-crimping position and vice versa, a pivot shaft common to said assemblies and on which the assemblies are pivotally mounted for independent swinging movements of the tensioning and sealing assemblies bodily relative to the foot assembly, said tensioning assembly being movable bodily between advanced and retracted positions to bring the tensioning wheel into and out of strap-engaging position respectively, said sealing assembly being movable bodily between advanced and retracted positions to bring the seal-positioning and seal-crimping jaws into and out of seal-engaging position respectively, a first piston and cylinder unit carried by said housing and operatively yconnected to the tensioning assembly, a second piston and cylinder unit carried by said housing and operatively connected to the crimping unit, spring means yielding biasing said second piston and cylinder assembly to maintain said jaws in seal-retaining position, first and second valve assemblies carried by said housing and each including a valve body movable between first and second positions, spring means yieldingly biasing said valve bodies toward their first positions respectively, said first valve assembly being operatively connected to said first and second piston and cylinder assemblies, said valve assemblies being effective when =the valve bodies thereof are both in their first positions to supply air to the first piston and cylinder assembly to maintain the tensioning and sealing assemblies in their retracted positions and also to Supply air to the second piston and cylinder assembly to maintain said jaws in their open seal-releasing position, said valve assemblies being effective when the valve body of the first valve assembly is in its second position and the valve body of the second valve assembly is in its rst position to supply air to the first piston and cylinder assembly to maintain the tensioning and sealing assemblies in their advanced positions, to supply air to the drive motor, and to exhaust air from the second piston and cylinder assembly to maintain said jaws in seal-retaining position under the influence of the biasing spring means associated therewith, said valve assemblies being effective when both valve bodies are in their second positions to supply air to the second piston and cylinder assembly to move sai-d jaws to their fully closed seal-crimping position, and manually operable means for selectively moving said valve assemblies between their first and second positions respectively.

6. In a pneumatically operable strapping tool for tensioning a loop of strapping about an article, said loop having overlapping free end and feed end portions threaded through a seal, and for thereafter crimping the seal about said overlapping portions, a foot assembly including a foot proper adapted to rest upon the article and having an anvil member adapted to underlie said feed end portion, a tensioning assembly including a rotatable straptensioning wheel and a drive motor operatively connected thereto, a seal-crimping sealing assembly including la housing and a crimping unit carried thereby, said crimping unit including seal-retaining and seal-crimping jaws movable from an open seal-releasing position through an intermediate seal-retaining position to a fully closed sealcrimping position and vice versa, a pivot shaft common to said assemblies and on which the assemblies are pivotally mounted for independent swinging movements of the tensioning and sealing assemblies bodily relative to the foot assembly, said tensioning assembly being movable bodily between advanced and retracted positions to bring the tensioning wheel into and out of strap-engaging position respectively, said sealing assembly being movable bodily between advanced and retracted positions to bring the seal-positioning and sealcrimping jaws into and out of seal-engaging position respectively, a first piston and cylinder unit carried by said housing and operatively connected to the tensioning assembly, a second piston and cylinder unit carried by said housing and operatively connected to the crimping unit, spring means yieldingly biasing said second piston and cylinder assembly to maintain said jaws in seal-retaining position, and manually operable valve means effective in a first position to supply air to the first piston and cylinder assembly to maintain the tensioning and sealing assemblies in their retracted positions and also to supply air to the second piston and cylinder assembly to maintain said jaws in their open seal-releasing position, said valve means being effective in a second position to supply air to the first piston and cylinder assembly to maintain the tensioning and sealing assemblies in their advanced positions to supply air to the tensioning wheel and also to the drive motor, as well as to exhaust air from the second piston and cylinder assembly to maintain said jaws in seal-retaining position under the influence of lthe biasing spring means associated therewith, said valve means being effective in a third position-to supply air to the second piston and cylinder assembly to move said jaws to their fully closed seal-crimping position.

7. In a pneumatically operable strapping tool for tensioning a loop of strapping about an article, said loop having overlapping free end and feed end portions threaded through a seal, and for thereafter crimping the seal about said overlapping portions, a frame adapted to rest upon the article, a pivot shaft on said frame, a tensioning assembly including a pneumatic drive motor, a gear housing and a tensioning member secured together and pivotally mounted on said shaft for rocking movement with respect to the frame between advanced strap-tensioning and retracted strap-releasing positions, a sealing assembly including a housing and a crimping unit, including movable seal-crimping jaws, secured together and pivotally mounted on said shaft for rocking movement independent of the rocking movement of the tensioning assembly and with respect to the frame between a retracted position wherein the crimping jaws are out of register with the seal and an advanced position wherein said jaws are in register with the seal, interengaging limit stop means on said frame and tensioning assembly establishing the retracted t and advanced positions of the tensioning assembly, interengaging limit stop means on said frame and sealing assembly establishing the retracted and advanced positions of the sealing assembly, said housing being provided with an internal cylinder, a piston slidable in said housing, -a plunger connecting said piston to the tensioning assembly, and control valve means for selectively applying air to the opposite ends of the cylinder to actuate said piston andthus simultaneously rock the tensioning and sealing assemblies toward and away from each other between their advanced and their retracted positions respectively.

8. In a pneumatically operable strapping tool for tensioning a loop of strapping about an article, said loop having loverlapping free end and feed end portions threaded through a seal, and for thereafter crimping the seal about said overlapping portions, a. foot assembly including a foot proper adapted to rest upon the article and having an anvil member adapted to underlie said feed end portion, a pivot shaft on said foot assembly, a tensioning assembly including a pneumatic drive motor, a gear housing and a tensioning feed wheel secured together and pivotally` mounted for rocking movement on said shaft toward and away from said foot assembly to bring the feed wheel into and out of strap-engaging position respectively, a sealing assembly including a housing and a crimping unit carried thereby, said crimping unit including seal-crimping jaws movable between open sealreleasing and closed seal-crimping positions, said sealing assembly being pivotally mounted for rocking movement on said shaft independently of the tensioning assembly to move the crimping unit into and out of register with the seal, said housing being provided with an internal cylinder, a piston slidable in said housing, a plunger connecting said piston to the tensioning assembly, and control valve means for selectively applying air to the opposite ends of the cylinder to actuate said piston and thus simultaneously rock the tensioning and sealing assemblies toward and away from each other between their advanced and their retracted positions respectively.

9. In a pneumatically operable strapping tool for tensioning a loop of strapping about an article, said loop having overlapping free end and feed end portions threaded through a seal, and for thereafter crimping the seal about said overlapping portions, in combination, a foot assembly adapted to rest upon the article and including an anvil member, a tensioning assembly pivoted to the foot assembly and including a tensioning member designed for cooperation with said anvil member, and a drive motor for the tensioning wheel, a sealing assembly pivoted to the foot assembly and including a housing and a crimping unit having seal-crimping jaws capable of opening and closing movements about said seal, said tensioning assembly and sealing assembly being independently movable toward -and away from pre-selected operating positions with respect to the frame, said housing being formed with first and second internal cylinders therein and with first and second valve chambers therein, a piston in said first cylinder, operatively connected to said tensioning assembly and effective to cause simultaneous movement of the tensioning and sealing assemblies toward and away from their respective operating positions, a piston in the second cylinder and operatively connected to said sealing jaws and effective to actuate the latter, a valve body in each of said valve chambers and movable between first and second operating positions therein, spring means yieldingly biasing said valve bodies to their first positions, said valve bodies: being effective when in their first positions to supply air to both cylinders to maintain the tensioning and sealing assemblies away from their operating positions and to maintain said jaws in their open positions, said valve bodies being effective when the valve body of the first valve chamber is in its second position and the valve body of the second valve chamber is in its first position to supply air to the first cylinder to maintain the tensioning and sealing assemblies in their operating positions, and to supply air to said drive motor, said valve bodies being effective when lboth valve bodies are in their second positions to supply air to the second cylinder to effect closing of said crimping jaws, and manually operable control means for selectively moving said valve bodies from their first positions to their second positions against the yielding action of said spring means.

10. In a pneumatically operable strapping tool, the combination set forth in claim 9, wherein. said manually operable control means comprises a valve stem on each of said valve bodies and projecting outwardly of the housing, a control lever pivoted to one of said assemblies and effective upon an initial depression thereof to effectively engage the valve stem of the valve body of the rst valve chamber to the exclusion of the other valve stem, and effective upon a subsequent depression thereof to effectively engage said other valve stem.

11. In a pneumatically operable strapping tool, the combination set forth in claim 10, wherein said lever is pivoted to the tensioning assembly and is shiftable bodily therewith.

12. In a pneumvatically operable strapping tool, the combination set forth in claim 10, wherein said lever is pivoted to the tensioning assembly and is shiftable bodily therewith, the combination further including a stem-em gaging dog carried by said lever, said dog being positioned ont of register with the valve stem of the valve body of the second valve chamber when the tensioning assembly is away from its operating position, and being movable bodily with the lever and tensioning assembly into such register when the tensioning assembly is in its operating position.

13. In a pneumatically operable strapping tool, the combination set forth in claim 12, wherein said stem-engaging dog is pivoted to the lever, is spring-biased to a terminal position, and is slidingly engageable with the valve stem of the valve body of the second valve chamber during movement of the tensioning assembly toward its operating position to prevent binding of the dog against said latter valve stem.

14. In a pneumatically operable strapping tool, the combination set forth in claim 12 and including, additionally, a secondary lever pivoted to the housing and having a portion thereof in register and engageable with the valve stem of the valve body of the rst valve chamber, said secondary lever being engageable by the control lever upon initial depression of the latter and constituting the media whereby the control lever is effectively engageable with said latter Valve body.

1S. In a pneumatically operable strapping tool, the combination set forth in claim l2, wherein said stem-engaging dog is pivoted to the lever, is spring-biased to a terminal position, and is slidingly engageable with the valve stem of the valve body of the second valve chamber during movement -of the tensioning assembly toward its operating position to prevent binding of the dog against said latter valve stem, and including, additionally, a secondary lever pivoted to the housing and having a portion thereof in register and engageable with the valve stem of the valve body of the first va-lve chamber, said secondary lever being engageable by the contr-ol lever upon initial depression of the control lever and constituting the media whereby the control lever is effectively engageable with said latter valve body.

References Cited UNITED STATES PATENTS 2,941,782 6/1960 Winkler 14C-93.2 3,032,075 5/1962 Hall et al IL10-93.4 3,150,694 9/1964 Meier MCs-93.4 3,198,2l8 8/1965 Ericsson et al. M10-93.4 3,211,186 10/1965 Bushman 14C-93.4

CHARLES W. LANHAM, Primary Examiner.

E. M. COMBS, Assistant Examiner'.

Claims (1)

1. IN A PNEUMATICALLY OPERABLE STRAPPING TOOL FOR TENSIONING A LOOP OF STRAPPING ABOUT AN ARTICLE, SAID LOOP HAVING OVERLAPPING FREE END AND FEED END PORTIONS THREADED THROUGH A SEAL, AND FOR THEREAFTER CRIMPING THE SEAL ABOUT SAID OVERLAPPING PORTIONS, A FRAME ADAPTED TO REST UPON THE ARTICLE, A STRAP TENSIONING MEMBER SUPPORTED ON THE FRAME, A SEALING ASSEMBLY SUPPORTED ON THE FRAME AND INCLUDING A PAIR OF SEAL-POSITIONING AND SEALCRIMPING JAWS MOVABLE FROM AN OPEN SEAL-RELEASING POSITION THROUGH AN INTERMEDIATE SEAL-RETAINING POSITION TO A FULLY CLOSED SEAL-CRIMPING POSITION AND VICE VERSA, A CYLINDER SUPPORTED ON THE SEALING ASSEMBLY, A PISTON SLIDABLE IN SAID CYLINDER AND OPERATIVELY CONNECTED TO SAID SEALING JAWS, SAID PISTON BEING MOVABLE BETWEEN A RETRACTED POSITION WHEREBY SAID JAWS ARE IN THEIR SEALRELEASING POSITION AND A FULLY ADVANCED POSITION WHEREIN THE JAWS ARE IN THEIR SEAL-CRIMPING POSITION, SPRING MEANS YIELDINGLY BIASING SAID PISTON TOWARD ITS FULLY ADVANCED POSITION TO CAUSE SAID JAWS TO ENGAGE THE SEAL UNDER PRESSURE SUFFICIENT ONLY TO ENGAGE AND MAINTAIN THE SEAL POSITIONED WITH RESPECT TO THE TENSIONING MEMBER BUT INSUFFICIENT TO CRIMP THE SEAL, AND MANUALLY OPEABLE VALVE MEANS FOR SUPPLYING AIR TO SAID CYLINDER TO AUGMENT THE ACTION OF SAID SPRING BIASING MEANS AND FORCE THE PISTON TO ITS FULLY ADVANCED POSITION.

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