BE472202A - - Google Patents

Description

       

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  Drive device for stretchers, advanced assemblers and other shoe-making machines.



   The present invention relates to a drive device for stretchers, advanced assemblers and other shoe-making machines, machines by means of which the upper of the shoe is stretched over the form by means of tensioning pliers which close and s' open alternately, performing pulling and lateral movements, as well as, where appropriate, a rotational movement around their own axis and also the corresponding return movements, and it is intended to provide an improvement to the gripper drive mode.

   According to the invention this result is obtained by means of a hydraulic drive comprising differential pistons and a spring-loaded overflow valve mounted in these pistons, all these parts cooperating with each other so that during the tensioning movement of the clamps the tensile force of these increases proportional to the increasing resistance of 4, increases up to a determined maximum value, the closing force of the jaws of the grippers increasing simultaneously.

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   The tensioning pliers of advanced stretchers and assemblers have in principle two basic operations to
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 to perform: first they must pinch the edge of the comb between their jaws, then they must tighten the comb by their pulling movement. ' To these fundamental operations
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 The grippers still add lateral release movements which are necessary, when the gripper jaws are open, to free the workstation for fasteners, as well as, of course, all return movements when the job is finished. . For pliers that act
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 feels in the wide part of the foot (metatarsal), that is to say the so-called traction clamps of the wide part,

   it is also desirable that they perform a rotational movement around
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 of their longitudinal axis, so that the upper stretches. 6 and @ applies suitably to the curvature of the instep of the last.



   The correct fitting of an upper, i.e. its attachment to the insole of the boot, depends mainly on the correct tension of the upper and its
 EMI2.5
 Gives application to the form, eluisi that of its stretching over the edge of the form and the rrair ;, op3xatiOns which are determined by the movement of hooking and pulling of the
 EMI2.6
 tensioning pliers.

   The material from which the upper is made, that is to say mainly leather, has the property of first opposing the tensile force to a relatively small resistance, which
 EMI2.7
 increases gradually, as the tensile force progresses, up to a well-determined limit value, which must not be exceeded under the trouble of tearing the line. This is why it is never possible to exceed this limit value during the tension of the upper, in order to avoid deteriorating the latter and also to maintain the elasticity necessary for the shoe during manufacture, when the upper. vamp was

 <Desc / Clms Page number 3>

 
 EMI3.1
 rise temporarily.

   So far we have not. not to: cfisaiuueit taken into account all the circumstances mentioned 'above in the known devices serving to stretch the upper on a form, as would have been necessary to obtain a well-stretched and temporarily mounted upper. This is how, for example,
 EMI3.2
 that 1 endeavored, for the known types of purely mechanically controlled mowing tongs, to ensure the possibility of adjusting the tension force,

   in order not to exceed the elastic limit of the material of the upper, but this effort of
 EMI3.3
 tension acts on the upper immediately upon completion of the tensioning operation, at a time when the resistance of the upper is still relatively small, as has already been said, which gives rise, when the material of the upper is thin, too sudden and too great an increase in tension
 EMI3.4
 ion and often causes an aeterloratlon and if necessary even one.

   destruction of the upper. To avoid this drawback, devices have already been proposed which slow down the speed of the tensioning movement of the clamps while the resistance of
 EMI3.5
 the upper increases; an uisposltü 'of this kind is used, for example, for the hydraulic coitictianuia of the tensioning movement of the grippers. In the case of this hydraulic solution, the reduction of the tension speed is obtained by moderation
 EMI3.6
 from the arrival of 111% uile to the cylinder devices.

   The spool which controls the arrival of oil to the working piston is subjected to the action of a set of levers driven on its side by the movement of the clamps, so that the arrival of oil to the piston of ' work is moderate in. same time during movement
 EMI3.7
 of tension deg clamps.

   The set of levers that are used will affect this adjustment is very complicated, so that for this device only the pulling movement of the grippers is controlled hydxalyically, while the control of the jaws to grip

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 the edge of the vamp is effected mechanically, in the manner used hitherto, so that the distance is pinched from the outset by a pressure whose value is no longer modified during the entire tensioning operation.

   Another drawback of the mixed hydraulic and mechanical control of the. gripper still resides in the fact that with this device the upper, once grasped and provisionally mounted, cannot be released from the grippers and that these cannot return to their starting position before the end of a work period , i.e. during the rotation of the machine control camshaft, (as is the case for example with most mechanical control devices), so that each after the end of a complete working period ue the machine before returning to the starting position.



   The device which is the subject of the present invention aims in particular to solve the problem of maintaining, to ensure the upper a suitable tension corresponding to the properties of the leather, an operation similar to that which has been recognized better lice the tension and the provisional mounting of the upper by hand according to the results of a long experience, because the worker who operates with a hand clamp begins first, ventilated having grasped the edge of the vamp, to kill with a little force, which it increases as the resistance of the vamp increases,

   while at the same time increasing the effort required) to retain the upper in the darts. An advantageous characteristic of the solution which is the subject of the invention also lies in the simplicity of the construction, in the possibility of controlling individual groups of grippers independently of each other and finally in the fact, which is not the least important, that the upper can be released from all the clamps by the only '

 <Desc / Clms Page number 5>

 
 EMI5.1
 movement of a lever during which phase of the machine's work.



   As the closing force of the gripper jaws
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 is also controlled .hydr al i qU6l1le nt, with the purely hydraulic coupling which is the subject of the invention, at the same time as the traction movement of the grippers, a considerable sLiip1irication of the tension of the device is obtained, although each gripper has its own order and thus constitutes an element
 EMI5.3
 of- independent work, some have these elements forming, by connections to the common distribution spools, the usual working groups such as the groups of tip grippers, side grippers and where appropriate pull grippers of the wide part,

  
The different work clamps are carried by cylinders
 EMI5.4
 'working which can be fixed at will to the frame of the maenine and in which the pistons which carry the fixed jaw of the gripper move, while the movable jaw of the gripper is mounted on a rod also made in the form of a piston at a end and guided inside the piston sleeve of the fixed jaw of the tip. This gives differential pistons
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 comprising a gap communicating with the interior of the working cylinder through a spring transfer valve.

   By making the liquid arrive under pressure,
 EMI5.6
 therefore first of all the closing of the jaws of the gripper by a relative displacement of the two pistons relative to each other and finally, by the displaceuiant'uas two pistons coannun in the 'working cylinder, first the pulling movement during
 EMI5.7
 whereby the above-mentioned increase in the tensile force and the closing force of the grippers takes place during pressure equilibrium in the spaces between the differential Distoxi and the working cylinder. A possible axial movement of rotation of the grippers is derived from the displacement of the latter

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 EMI6.1
 in the working cylinder.

   The worker causes 1 racaxocnae of the edge of the vamp by the lildctioires of the pliers and the tension of the vamp by the tensile force by the pliers by controlling the corresponding drawers by means of an angled lever and he can
 EMI6.2
 order a group of pliers independently from others, not only by report to.

   the position of the work, but also with a view to recalling the starting position, which is very advantageous when it happens by chance that the rope of the elile1! @ was not properly grasped and stretched by a single group of pinças only * Only when the upper has been properly
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 held that we change the adjustment position of the spools on the camshaft of the machine, which can then perform autol11atique nt the rest of the work, such as the *, il., 5e in shape and the provisional fitting 'of the upper.



  Other advantages and characteristics of the present invention will result from the following description of an exemplary embodiment which is shown in the accompanying drawings, in which:
 EMI6.4
 Fig. 1 is a schematic view of the assembly of the control device according to the invention.
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  The ig .. 2 is a longitudinal section of the clamps tendeulaes in the position of a3pdxt La éig. 3 is a sectional view of a detail of the working cylinder of the grippers stretched8u3.:;;s (in the upper part, the parts ae are in a position in which the jaws' of the grippers are closed, but the gripper Gllo ;;; - l1lêLl18 does not yet exert any tld.Ctioll force; the lower part shows the position of the elements while the gripper exerts its tensile force).
Fig. 4 is an elevation, with a partial section,
 EMI6.6
 the piston s2 being in the starting position.

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     Fig. 5 is a view of one of the distribution chambers, the pistou occupying its middle position.
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  Fig. 6 is a view of the same diatriuution chamber as that of FIG. 5, the piston occupying its ex- position. left throne.



  The: 6ig. 7 is a schematic cross section of the idle drawer.
 EMI7.2
 The 7ig. 8 is a view of a detail for the drive of the piston of the idling drawer.
 EMI7.3
 The tensioning device of the toe part (The comb of a shoe is constituted, in the assembly machine
 EMI7.4
 built according to the invention, Liaz, a usual set of tensioning pliers, one of which, 1 ,, pliers.1 (Fig. 1), e; 3t the poinzotte pliers, the pliers 2, 2 'being the side pliers and 3.3 'the pulling pins' of the wide part, the number of pairs of pliers can also be increased as needed.

   The different gripper devices do not differ from each other
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 that by the shape of the jaws and also, with regard to the grippers 3, 3 of traction of the wide part, in that these are provided with a device allowing these grippers to rotate around their longitudinal axis, this which is not necessary for the point and side pliers. '
The control of all grippers is fully hydraulic.
 EMI7.6
 league. The pressurized liquid, such as oil for example, is taken from a reservoir 6 by a pump 4 actuated by an electric motor 5 and discharges into the pipe passing through a filter 8.

   It is appropriate that the; reservoir 6 is housed in the lower part of the nacnine. Pump 4 sends the oil through a
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 conduct y, by the inta! 'lédi cl.Ü'1 ;;) of a drawer 10 said to run at; vacuum and through the outlet pipe 11 of this drawer, into a
 EMI7.8
 pressure pick 12 to which all the distribution drawers of the tensioning pliers are connected. At the end of the, cou-

 <Desc / Clms Page number 8>

 
 EMI8.1
 pressure pick 12, there is a safety flexible 13 of the type
 EMI8.2
 known, imnie with a small flywheel of the lLcit10duV're 14 allowing to regulate the pressure of the oil in the line 12. The, valve 13 'allows the excess oil contained in the pressure line
 EMI8.3
 return to tank 6 through a pipe 15.

   The pressure that reigns
 EMI8.4
 gne in line 12 is controlled by pressure gauge 16.



  The piston, 1 (Fig.?) Of the idle slide 10 is movable, inside the slide 17 again which can be communicated through a pipe 9 with the pump 4, through the discharge pipe 11 with the pressure line 12, and by an evacuation pipe 18 with the tank b. The drawer CÚQ.l110lè 1. is provided, between the orifice of the conduit> 9 and the pipe 11, with a recess 19 having the. Llllile languor that a corresponding avrieimnt 20 practice ddil8 the piston the Lv pihtjii 21 has, to. its left end, a., a.dicc coniquç 22 jmni to '<ilettes 23 on which a' rests a spring 24 which holds <1 a ...! OU35 <31 'the piston 21 to make it come out of the .

   C1d.1OJ.'ç 1 / <. 'xt.uit the right of the piston 21 carries a cJ.18ville 25 coming out of the body of the piston 21 on both sides (see Fig. c) and a rolling roller 2tio The piston 21 can be actuated by the worker at rMy =: n d.'Ltli lcvi8r bent or automatically by the lùdcJ.11n8, COliliil8 it was varied further, and he noted;: G't1i18Xlt intended to allow 1. aai'cne vacuum of-pump 4 when does not need ol ± 1.u11e or ree3ion in line 12, during the stoppage of the various work aispoaitife. A r2tenuo valve 152 on which a spring acts 15) prevents the pressurized liquid .o contained in ld. discharge line 12
 EMI8.5
 to go back *
 EMI8.6
 As we already have. ait, 1:> diffa.

   Otitis pinaes are almost Úll18 ty, t} <::, -, t onaque ti "ju.0c de pincca has a tlloir of diatzioutidn CO.1lilUÙ This is why it will probably suffice

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 'Describe below the arrangement of a single group of grippers and its distribution spool.
 EMI9.1
 



  Each gripper constitutes an independent mechanical element housed in the working cylinder 2? ogig-0 2) communicating permanently with a tubular 26. The tubular appendage 2d is clamped in an adjustable frame 29 by means of which the clamp can therefore be fixed to supports of known type, not shown, which can be aoiùiundé3, <u means of uain levers, so that we can move each clamp relative to the piece worked. 3, as oelast'nëoessH.ie for example when moving from one kind or size of shoe to another, or as it seems necessary for the fitting of the upper on the last.

   The position of the clamps 1 of the point can be adjusted in the longitudinal axis of the cnaussure to be manufactured; the clamps 2, 21 of the sides can rotate in the direction of the sides, converging on the toe of the shoe and can moreover also adjust their position laterally to bring them at different distances from the longitudinal axis of the cry, while that the traction clamps of the wide part, can be adjusted both longitudinally and transversely with respect to the axis of the shoe.

   The possible adjustment of
 EMI9.2
 The grippers of the device according to the invention is remarkably easy compared to known machines of this kind, because the grippers themselves can be made very light owing to the simplicity of the hydraulic control.



     The tubular appendage 28 constitutes a guide for a sheath 30 at the upper end of which are fixed the fixed jaw 31 of the tensioning clamp and an axis 32 around which the movable jaw 33 of the clamp rotates. The sheath 30 is connected by means of a hollow rod 34, which passes through

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 to a nut 35 closing the upper part of the travel cylinder
 EMI10.1
 vail 27, to the hollow piston 37, which has a pCÙ: t1cul1àre shape visible in the Figs. 2 and 3. 'The tramsvcraa wall, the 3zi of piston 3? is provided with a series alouvaituie 39 which coitumniquer the interior 40 of the hollow piston with the space 41 which is above the piston.

   The outer face of the transverse wall 38 carries a seat for the valve 42, which can slide on the threaded part 43 of the piston 37. This valve 42 is applied to the seat of the transverse wall 38 by a spring 44 which rests on it. a collot 45 Screwed to the upper end of the
 EMI10.2
 threaded portion 43. In addition, the piston liner 37 is also provided with a series of intake cases 46. A rod 47 is guided in the hollow tie rod 34 and a
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 piston 48 guided on the inner surface of pist0n 37 is attached to the end of this tisu.

   The piston 4d is provided with seals 49 on each side and, on its inner face, it carries a spacer sleeve 51 (.I! 'IG $ 3) L). In which openings 50 * ud upper part of the rod 4 carries an appendage tuoul.ài> e 52 (8ig. 2) whose forked end 53 is provided with grooves 54 in which can slide a pin 55 cooperating at the same time with the guide slide 56 of the jaw mobile 33 of the, clamp, jaw that turned around
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 . from 11 aXe 32.



  A sheath 5? is also fixed on the rod bzz this sheath carries, on each side, attack surfaces 58 which come from
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 Do not act on the rounded ends 3 i of two follow levers 60 rotatably mounted on axes '61 in nes notches 62 of 1: 1, sheath 30. The operation of these safety levers 60 will be described later.



  The fixed tubular appenàlce 28 is provided with a groove 64, in which slides a pin 65 fixed to the sheath 30. This

 <Desc / Clms Page number 11>

 
 EMI11.1
 guide groove 04 is rvctiliye for the grippers from there anointed and from the sides, so that the sheath 3U and with? lia also the jaws 31, 33 of the grippers always have the same axial position each time the sheath 30 moves in the tubular appendix 28.
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  For the part pull pliers. wide, 9ar against, the v> riL1nu: re 64 practiced in 7:. the upper part is curved, which has the consequence that during the movement of the sheath 30 in the tubular appendix 28, a rotation occurs. axial of the sheath 30 with the clamps following the curvature of the groove 64.



   The working cylinder 27 has three inlet lines for the pressurized liquid, one at point 66, opening
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 in the space 41 above the piston 37, another 61, which opens into the space 40, that is to say in the space between the pistons 37 and 48 and finally a pipe 68, which leads to
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 the space 69 below the two pistons 37 and 48. The bottom of the working cylinder 27 is closed by a nut 154, a part of which, that which is inside the working cylinder, has a 4-ente recess 155 extending, qli height, to about halfway through inlet 68.

   The upper edge of this recess 155 is provided with recesses 156 still allowing the passage
 EMI11.5
 pressurized liquid coming from the inlet pipe 6d under the piston. 37, even when it is in its lowest position, in which it rests on the recess 155 ..



   The distribution of the pressurized liquid in the working cylinders 27 of the different grippers is ensured by particular distribution spools, one of which is shown in
 EMI11.6
 detail, by way of example, in fig 4. The drawer ocrps 60 is mounted on the frame of the machine, in the lower part of the latter (see Fig. 1) and it comprises three cilea-6res? 72, 73. Ch1wres 71, 72 are distribution chambers and the

 <Desc / Clms Page number 12>

 
 EMI12.1
 room 73 is due, reduction.

   One, J18ton '74 acts in chamber 71, piston 75 in chamber 72. ;; t piston 16 in chamber 73 Cnaliibers 71 and '72, as well. that their piretons 74 and 75. are entirely iù, ii, tiqÙ = 3rd id .cnminxe it communicates through the inlet pipe 11 with the discharge pipe 12 (gig. 1) and it has, on the one hand, a pipe flow 78 leading to the reservoir ci 2tt on the other hand, the jasaage openings 79 and 80. The same roles are fulfilled for the chamber 72 by the inlet port 81t 1 "flow port 82 and the openings d 'Evacuation 83. 84 The passage openings 79 and riz4 connect with each other by the channel 85. The passage opening 80 COi1l.illunique with the onambre of, education f / 3 which, it, cOl1UJlunique little: the opening 86 with the outlet the.

   The pedestrian 74 is provided with three recesses tri7, 8d, 89, two of which, the recesses 237 and 89, communicate with each other via the intermediary (the openings. 90, 91 and of the channel 92 which, has the; xt1.étit, left, part of piston z4 and dueaoucnr7 in part a. chamber 71 where it is found 110: r1f108 of flow.'lll <:: Jnt- The orifice of channel 92 is closed by a valve 93 which slides on a W tid4 94 fixed on the axis 95 uaiis the channel 92. The valve 93 is applied to its seat
 EMI12.2
 ,
 EMI12.3
 by a spring 96 which rests on a collar 9 fixed to the end of the rod 94.

   The valve 9t only supports: a fatal pressure Qu emerges and its purpose (ie lllc11ntenll 'continually a column of liquid sau3 pressure inside the cavities interconnected by 1 s recesses 8'i Ht 39p crest; â-Qixe in the flow lines 79 and 80 and in the working cylinder, so that the device (the work can be started immediately at any time. This also prevents the formation of 'au1les air in 1. liquid under 1) 138 ::; 10n and saves any unnecessary backflow of 11qU1'1 under J, .JlesB101l.o The piaton 74 is supported by the r36Bion of a'XS30rt ge which want it

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 maintain in the position shown in FIG. 4.

   A pebble
 EMI13.1
 bearing 79 went up to. l 't; xtrélili1 :. right of the piston follows, under the action of the spring gd, the contour of the drive cam 149, (21g. 1). An ankle 100 fixed in the body of the piston 4 so, t of this body of the ueax dimensions and t0111ùe, when the piston 74 occupies its middle position, in a recess 101 of a lever 102,
 EMI13.2
 which can rotate freely around an axis 103 mounted oemeure on the drawer housing.

   When the cneville 100 has fallen into the recess 101, the piston '? 4 is therefore kept in the same position as long as. the lever 102 is not raised ae sogibvelasat can be effected by means of a lever 104 actuated by the worker in a way which will be described later and acting on a lateral arm
 EMI13.3
 105, or by means of a caruc acting on the rounded end '106 of the lever 102.



  The piston 75 which acts in the cylinder 72. Is constructed like the piston 74 'and its elements which will be mentioned later will therefore bear the reference numbers as those of the piston
 EMI13.4
 14. The only parts that will have new part numbers are, roller 10?, Cneville 108, the recess houses the lever 111, the arm 112 and the rounded end 113.



  The two piatones 75, '? 4 together have three working p0axtions V1i;) 101st, 1d right marginal position in FIG. 4, the middle position (lcJ.1S in Fig. 5 and the left marginal position in Fig. 6.
 EMI13.5
 



  The reduction of the pressure stubbornly causing the tensile force of the grippers is provided by the piston 6 which moves in the camber 73 communicating with the passage opening 80.



  The piston 76 is subjected to the pressure of a spring 114, the pressure of which can be adjusted by means of a small handwheel
115 (see Fig. 1) via the bevel wheels 116
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 and 'a nut 118 mounted on there via 117 and on which 03.' aj: Jj; 1u1e a

 <Desc / Clms Page number 14>

 
 EMI14.1
 end of spring 114. Movement of piston 74 to the right
 EMI14.2
 te '(in the end. 4) is limited by a pin 119. The pressure which reigns in the CJl1rluite behind the reduction spool is controlled by a manometer 120 (3 ilg, 1) connected or channel 121 (' ig.4 ) which loosens in the passage opening 80.



  There is a distribution drawer for a group of pliers. These drawers are intended for drawer 122 (21g. 1) *,>, the clamp (I point at l, drawer 123 at the lower ae sides 2 '2', and drawer 124 for the 3rd 1 clamps of the wide part. The attiiuiition of the different drawers to the; xouFx: if the clamps are indicated in the 9ig * 1 and the comvu) ics, tions are ensured preferably
 EMI14.3
 This by means of flexible pipes. When a single drawer orders -
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 several forceps, we use a dietri'outsur of known type which allows to distribute To, several L) 03te9 of tlclVaÎ1 the liquid
 EMI14.5
 pressurized from a single spool outlet.
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  All the gripper groups are connected to the different drawers in principle in the third way * C 'and why it will probably suffice to describe in detail an other connecting hiode, for example that of the side clips 2, 2' to the drawer 125.



  The outlet port?. 9 (jJ'16 4) is made. directly by a flexible pipe 125 (Fig. 1) at the point of arrival 03 (r'g.2) of the working cylinder of the gripper 2 and the outlet 84 is connected directly by a flexible pipe bzz at the point d 1 inlet 68 of the clamp 2 '. The pressurized liquid coming out of them-
 EMI14.7
 flow port 80, where a reduced pressure prevails is sent
 EMI14.8
 by a 30uple pipe 127 in a known distributor 128, at the outlet
 EMI14.9
 shot from which it is sent, on the one hand by the flexible pipe 129 to the inlet pipe 6? clamp 2 and, on the other hand, by the
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 flexible pipe 130 to the inlet pipe b7 of the clamp 2t The
 EMI14.11
 pressurized liquid exiting through opening 83 is sent from
 EMI14.12
 / 1

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 the same way through the pipe.

   flexible 131 to the distributor 132 and, to the output thereof; through the flexible pipe 133 to the pipe
 EMI15.1
 dtàXrÎVée 66 of the clamp 2 and by 1.6 flexible pipe 134 to the inlet pipe of the clamp 2 '. For the tip clamp li a distributor is not necessary; The outlet opening 80 of the drawer 122 can therefore be connected directly to the inlet pipe 67 of the clamp 1. The tensile force of the clamp 1
 EMI15.2
 and controlled by a manometer'133 and that of the clamps 3, 3 'of' traction of the wide part, By a manometer 136.



   The control of the distribution drawers takes place in two ways, on the one hand by the worker by means of a set of levers and, on the other hand, automatically by means of trays-
 EMI15.3
 cams. In the: bi.,. L the control, by means of 'levers, of the distribution spool 123 of the side grippers 2, 2t is shown schematically. This lever control device consists of an angled lever 137 which can move aside laterally by rotating about an axis 138. This angled lever 137 is connected by means of a tie rod 139 to a lever arm 140 wedged on a tree 141.



  The shaft 141. is rotatably mounted in suitable bearings and it still carries several 'lever arms wedged on it,' the arm
 EMI15.4
 lever 142, which acts on the pin 2j> (Dig.?) of the piston 21 of the idling spool 10, as well as a forked lever 143 acting by an arm 144 on the lower part of the pin
 EMI15.5
 100 (7'1 ;. 4) and by the other arm 145 on the pin 108, when the shaft 141 turns in the opposite direction to the movement of the needles.
 EMI15.6
 them of a watch.

   The arm 144 is slightly, offset to the left relative to the arm 145, this offset corresponding to half the length of the stroke of the pistons? 4 and 75? as we will see below., A forked lever 146 is still wedged on the shaft 141 ,. lever including arms 104 and 111, which have already been mentioned more
 EMI15.7
 top, act on the ankles 105 ât 112 (Fig. 4) when ltar-

 <Desc / Clms Page number 16>

 bre 141 rotates in a clockwise direction. The drawer 122 is controlled in the same way, the control of the two drawers being able to be effected by means of a single angled lever 137, the movements of this lever being combined forward and backward.

   For reasons which will be explained later, the pulling clamps 3, 3 'of the wide part, and consequently also their drawer 124, are only controlled automatically by means of cam plates.



   As will be seen later, the idle slide piston 21 (Freeze?) Must be moved to the left, even when the control lever 137 is moved to the right. This mode of action is obtained, for example, by means of a device indicated in FIG. 8 and in which the lever 142 pushes the pin 25 of the piston 21 to the left, through a connecting rod 157, and a beam 158 rotating about an axis 159 fixed to the frame of the machine, when it moves away to the right.



   The possible automatic control of the distribution spools is ensured by (the cam plates mounted on the shaft 14? Driven by the motor 5 by means of a gearbox 143 and a one-way coupling not shown There are two cams for each spool, the timing, cams 149 and 150 for spool 12j. The idle spool 10 is controlled by a cam 151.



   The operation of the device described is as follows:
When it is started, the electric motor 3 drives the pump 4, which sucks the pressurized liquid contained in the tank 6 through a filter 8 and sends it through a pipe 9 into the idle slide 10. . As long as the machine itself is still stopped, pump 4 runs without load, as the pressurized liquid coming out of the pump can return

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 to the tank 6 by passing through the idle slide 10 without providing any pressure work.

   The piston 21 of the idling spool 10 then occupies its right-hand marginal position, that is to say a resulting position, according to FIG. 7, movement of piston 21 to the right over the entire length of the recess
20. In this position the pressurized liquid from the pipe
9 can pass through the recess 19 around the conical appendage
22 of the piston, then between the fins 23 and enter the discharge pipe 18.



   The worker then takes the workpiece and introduces it into the machine, proceeding in much the same way as for most machines of this type. It begins by inserting the edge of the upper, at the point of the toe of the shoe, between the jaws of the clamp 1, which is in its highest position and which is open, like all the others. pliers. He then moves aside the cranked lever 137 (Fig.l) and thus causes, via the drawer 122, the closing of the point clamp, which clamps the vamp, which allows him to stretch it in the direction 'of the longitudinal axis of the form. and to fix it properly.

   This done, he introduces the side edges of the upper into the side grippers 2, 2 ', then, after lowering the form by pressing it down. sole of known type not shown, it also closes the jaws of the clamps
2, 2 'by moving the angled lever 137 to the left, which allows it to stretch and fix the upper on the sides as well. The clamping of the upper by the traction clamps of the wide part and the tension of the upper in this wide part of the form takes place only after the worker has made sure that the upper is suitably stretched in the tip part, as well as on the sides.

   As the pull clamps of the wide part can no longer significantly influence the correct tension of the clamp.

 <Desc / Clms Page number 18>

 
 EMI18.1
 comb grasped and retained by the pliers of the tip and the sides,
 EMI18.2
 it is not necessary for him to be able to order these wide section pulling pliers himself.

   On the contrary, in the example shown, these clamps do not,; 3 .Jút c CMi, lc1l (iê ',: that automatically by the camshaft 14'? Before starting the t.4..i1 tOUt23 1 .? s clamps are therefore open, c oi; 1 = :: e we have already said r bt the point clamp l, as well as the clamps of dimensions 2, 2 'are in their highest position The clamps 3, i traction of the wide part can be a little lower, so as not to interfere with the introduction of the edges of the vamp ü.a, the other darts, and only then, when it is necessary to tighten the vamp in these traction clamps of the largo part, that the jn remakes these clamps,, Before starting work the device of COioa, I7, dG 'of the diff:

   zat, s clamps, whatever they may be, occupy the position shown in Fig. 2, while, 3 the soft pistons 74,? 5 of the
 EMI18.3
 corresponding distribution spool are still located, couple ie
 EMI18.4
 shows the 7.'i6 4, from the precetained operation, under the pressure of the cavity 69 of the working cylinder 2? (ii6 2) clamps, because they are '' 311 CO,;. l: lu; Ücatiol1 with the discharge line 12 (end. 1) through the pipes 125. 12v, the outlets 79, 84, as well que les êVirle !, 18nts d3 and the ,; ' inlet pipes 77, -31 The two pistons 37 and 48 of the clamp occupy their highest position, because no pressure 1.12 dan? the two cavities 40 and 41 (Fig * 2), because these cavities are ex. 0ùiJlunicatiol1 by conduits co: 1; eponùait;:. S <.v #> c 1. = s 8, flow niÚces 80 and J.3. which are,: UX-, llj ,, 1 (8 1.,. li:

  > .t 'to buyautelies flowed 78 and 82 through l9éviàezac: t 87, opening 90, channel 92 and valve 93.



  Now, as soon as the worker has introduced the edge of the vamp between the open knots. 31 33 clamp it,

 <Desc / Clms Page number 19>

 move the angled lever 137 (Fig. 1) towards la. left, so the upper is gripped and. tensioned until the tension movement of the gripper stops. By folding lever 13? to the left, the worker turns the shaft 141, which also moves the levers 142, 143 and 146 to the left.

   However, during this movement, the levers 142 and 143 alone come into action, the operation of these levers being distributed over time, following their inclination, so that the lever 142 acts on the pin 25 of the piston 21 of the slide valve. idling at the same time as the arm 144 of the lever 143 acts on the lower part of the pin 100 of the piston 74 of the distributor spool, while the arm 145 of the lever 143 acts only later on the pin 108 of the piston 75, the delay in relation to the dimensions in length being equal to half of the stroke of the piston 74.

   The lever 142 pushes the piston 21 of the idle slide to the marginal position shown in FIG. ? and wherein the flow of the pressurized liquid in the discharge line 18 is stopped and the flow released to arrive in the discharge line 12, the discharge liquid itself opening the check valve 152.

   The piston 4 of the distribution spool comes, under the action of the arm 144 of the forked lever 143, to occupy its left marginal position in FIG. 6, while the piston 75 occupies a middle position in FIG. 5 under inaction of the arm 145e This results in the liquid under pressure from the discharge line 12 entering through the branch line 7? and levitating 88 in the flow port 80, to which the reducing chamber 73 is connected, in which the pressure is reduced in the desired way according to the setting given to the spring 114 by the operation of the small handwheel 115,

   the liquid under pressure in excess being discharged if necessary by the piston? it and escaping by

 <Desc / Clms Page number 20>

 the opening 86 to enter the drain pipe 78 (Fig.



  4). The pressurized liquid whose pressure has been reduced between, through the flow opening 80 'and the corresponding pipes, in the inlet opening 67 and, by. following, in the cavity 40 (Fig 2). At the same time, the pressurized liquid escapes from the cavity 69, which was under pressure until that moment, and enters through the corresponding pipes into the openings 79 and 84, from which it then leaves only through the opening 79 , which communicates through channel 85 with opening 84, to then pass through recess $ 9 of piston 74, then through opening 91, channel 92 and through valve 93 in discharge pipe 78.

   During this working phase, the pressurized liquid cannot enter the discharge pipe 82 directly, passing through the opening 84, as long as the piston 75 occupies the mean position mentioned shown in FIG. 5 and in which the inlet line 81, as well as the flow openings 83 and 84 are closed * As already seen. Said, the pressurized liquid exiting through opening 84 can enter channel 85, which leads to the discharge, only the cavities connected to flow orifice 80 ceasing to be under pressure, but remaining filled with liquid under pressure, a result which is due to valve 93, which is spring loaded.

   As a result, as soon as the liquid under pressure enters the cavity 40 of the gripper working cylinder, the piston 48 first performs a downward displacement 0 obliquely from left to right and up and down in the cylinder. Fig. 2), so that this piston 48 comes to occupy the position shown in the upper half of FIG. 3.

   During this movement the piston 48 drives the rod 47 with the forked tubular appendage 52 and the pin 55, which slides in the groove 56 of the movable jaw 35 of the gripper, rotating.

 <Desc / Clms Page number 21>

 this jaw around the axis 32 in such a way as to appeal against the fixed jaw 31 of the clamp by pinching the edge. of the vamp * As a result of the closing of the jaws of the clamp, the rod 47 and the piston 48 can no longer continue to move downwards;

   the pressure begins to rise in the cavity
40. Until it is greater than the force of the spring which loads the valve 42 and opens this valve, the liquid under pressure begins to pass through the openings 39 in the transverse wall 38 to enter. in the cavity 41, as can be seen in the lower half of the
Fig. 3.

   As long as the inlet cover 66 of the cavity 41 remains blocked by the piston 75 of the distribution spool, as mentioned above, the pressure which reigns in the cavity 41 acts on the entire surface of the hollow piston 48 and begins to push back this,.! son 48 further towards the oas with the piston 37 (to the right in Fig. 3), until the two pistons come to occupy the position shown in the lower half of the Fig. 3.

   During this common movement of the pistons 37 and 48, the tubular appendage 28 is also driven with the jaws 31, 33 'of the gripper, between which jaws is the pinched edge of the upper, which is thus stretched over the mold. * The pressure in the cavities 40 and 41, which are now interconnected, then increases in proportion to the resistance that the upper 09, Poses 4 the tension force, so that not only the tensile force clamps increases, but also the clamping force of the jaws 31 and 33 of the clamp, jaws which are applied to each other.

   The pressure increases in the cavities 40, 41 until it reaches its maximum value, which is determined by the reduction piston 76, after which the pulling movement of the clamp stops.

 <Desc / Clms Page number 22>

 



   If the worker desires to reach the maximum pressure of the gripper as quickly as possible, he holds the lever 137 in its extended position to the left until the tensioning movement of the gripper ceases. As soon as the worker releases the bent lever 137, it returns by itself to its starting position under the action of the spring 24 of the idle spool 10, the piston 21 also being pushed back to its position. marginal on the right, and the cneville 25 of this piston 21 driving the lever 142 of the shaft 141.

   However, the worker will not always use all the reduced tensile force of the clamp and he will allow the tensile force to increase in leaps, depending on what is necessary for an upper which is possibly less resistant by acting alternately. , on the angled lever 137, so as to move it to the left and then release it, which has the effect of interrupting the pulling movement of the pliers, then re-establishing it, an operation that the worker can repeat until that the upper is properly stretched.,
As we have just said,

   after each release the angled lever 137 automatically returns to its starting position 'and the distribution piston 21 of the idling spool 10 comes to occupy its right-hand marginal position, in which the arrival of the pressurized liquid in the delivery pipe 12 is stopped. As the crank lever 137 returns to its starting position, the forked lever 143 also moves away from the pistons 74 and? 5 of the distributor spool and these two pistons also tend to return to their position. starting under the action of the springs 98, that is to say in their right-hand marginal position.

   They. are prevented, however, by the levers 102 and 110, in the recesses 101 and 109 of which 1 s protrusions of the pins 100 and 108 have already fallen before. The recesses 101 and 109

 <Desc / Clms Page number 23>

 therefore retain the two pistons 74 and 75 in their central position in Fig. 5, a position in which the inlet openings as well as the outlet openings of the distribution spool are closed. The release of the angled lever 137, which has been folded out on the outside, therefore causes a locking of the entire working device of the grippers in the position in which they are at the time of the release of the angled lever.



   Then, during a repeated operation of the elbow lever 137 -and- its folding to the left, when only the piston 74 has been moved to the left in the distributor spool, until it reaches the case. If the piston 75 remains in its middle position again to its left marginal position, to which it has already been brought after the first operation of the elbow lever), the pressurized liquid acts again in the cavities 40 and 41 of the working cylinder of the gripper, so that the increase in pressure increases in these cavities if necessary up to its maximum pressure.

     if it happens that the upper is badly pinched and badly stretched on the form, it is possible to disengage it from the clamps and to return the whole of the device to its starting position by snapping the lever bent 137 in the opposite direction, that is to say to the right, the arms 104 and 111 of the forked lever 146 coming to meet the pegs 105, 112 of the levers 102, 110 and lifting these levers, so that the pegs 100 and 108 come out of engagement with the recesses 101, 109 of these levers and that the pistons 74, 75 of the distribution spool return under the action of the springs 98 to their right-hand marginal position shown in FIG. 4, position in which the two cavities 40 and 41 of the tensioning clamps are connected to the discharge.

   However, as the free running is also stopped when the elbow lever 137 is folded to the right, i.e. the piston 21 of the spool 10

 <Desc / Clms Page number 24>

 idle is pushed back to its left marginal position in Fig. 7, position in which the entry of the pressurized liquid in the delivery pipe 12 is made free,, this liquid passes into the inlet pipes 77 and 81, through the recesses 88 of the pistons 74,75 and through the openings 79 , 84, as well as in the corresponding flexible pipes and enters the cavities 69 of the working cylinders 27 of the grippers, so that the two pistons 37 and 48 thereof return to their upper position, shown in FIG. 2,

   the pliers then opening and going up ..



   In addition, it is also possible to correct the position of the upper already gripped by the clamps and stretched by them, this result being obtained by moving some clamps, while they are closed. , with respect to the support of the boot, which can be done by means of a set of known levers, not shown, acting on the outer frames 29 of the working cylinders of the grippers.



   It may also happen that the upper is not properly inserted into the still open jaws of the clamps, that the latter close, but do not pinch the upper and perform their pulling movement when empty. In this case, as the movement of the clamps does not meet resistance, it could happen that the two pistons 37 and 48 descend until, meeting with the withdrawal 155 of the locking nut 154 of the cylinder of the cylinder. work 27. The same could happen if the pliers pinch the upper properly, but tear it '' 'while stretching it.



    This is why, on the rod 47, the sheath 57 carries attack surfaces 58 which, when the jaws jl, 33 of the grippers close, come to rest on the rounded ends 59 of the safety levers. 60, so that these deviate. This prevents the clamp from descending to the above mentioned encounter ,, '!

 <Desc / Clms Page number 25>

 because the rounded ends of the safety levers 60, ends which come out of the. sheath 30, abut against the sur-. anterior face 63 of the tubular appendage 28 and thus prevent the clamp from continuing to descend to an inopportune position.



   The clamps 3, 31 of tiaction of the wide part, clamps which were lowered throughout the duration of the preparation of. the upper for its introduction into the clamps 1, 2 and 2 ', are released and brought, by the admission of pressurized liquid into the cavity 69, to their highest position shown in the
Freeze 2.



   The first phase of the machine's work is finished when the upper has been stretched by the toe and side pliers. The second phase, which is characterized by the automatic operation of the machine, then begins.



   The edge of the vamp is inserted between the open jaws of the wide part traction clamps 3, 3 ', and the clutch of a coupling rotates the camshaft 147, the cams of which are intended to control the work of the grippers during the remainder of the work, by passing the pressurized liquid from the discharge line to the work rolls through the dispensing spools.

   When the shaft 147 is set in motion, the cam 151, which acts on the roller 26 of the piston 21, first stops free running and thus connects the delivery pipe to the pump, the distribution spool 124 being actuated simultaneously, more or less as before by the angled lever 137, by means of other cams, so that the pulling pliers 3, 3 'of the wide part close, grasp the edge of the comb and tighten it in the wide part of the shoe, while performing a simultaneous movement of axial rotation already mentioned. When the pulling movement of these clamps is completed, the pistons 74 and 75 of the

 <Desc / Clms Page number 26>

 distribution drawers of all the grippers occupy their middle position shown in Fig. 5.
 EMI26.1
 



  At this time, c 1 is to say when mounting 1 em--. comb on the form is finished, the other availables of the assembly machine are put into action, such as for example a
 EMI26.2
 tip trainer no 1 c .... JrJsmltj coni'.zatatrux which applies 1 vamp under pressure on the base in the part of the tip
 EMI26.3
 and the e;>:> thus does not move and release itself from its tension when it is released from the clamps, this release having to take place so that the re.l.):

  ) us <3em "s due known typa, not shown and finally the nailing or glue press device can come into action for a6 $ Urr the definitive fixing of IleMpeig2ler 'It is therefore not enough that the clamps simply open and release. -
 EMI26.4
 on the edge of the ei * eigas, it is necessary that they descend a little more, so as not to interfere with the other operations mentioned above.
 EMI26.5
 



  The guvPrturi of the jlâcnoires back pliers and consequently the liberation of the l1el: the line is carried out by the caties 149 and 150 which, by their action on the rounded ends 106 and 113 of the levers 102, 110, raise these 1: 3vi <irB and remove from the recesses 101, 109 the C118VIll (IA 100 and 10d 1'dnda.nt ep newly and under the action of the 9ci springs, the Cal, h3 149 penuet the Son 14 to return to its marginal position on the right ( see Fig. 8)., while the cam 150 still leaves the piston 75 in its middle position (see Fig.

     5). In these positions of the pistons 74, 75, the
 EMI26.6
 cavities 40 of the working cylinders of the grippers are en'col1ID1Ul'l1Ca.tion through the inlet openings 46 '(xi, 3) with the inlet pipes 6 ?, as well as with 13F.1 ecoUlement pipes' 80 of the distribution spools by 18 corresponding couple pipes, and these openings cOl1uniquel1t fJll ') <' hll'il (: 3S through 1 through the events 87, the openings 90t of the channels 92 and the valves 93

 <Desc / Clms Page number 27>

 with evacuation.

   This has the consequence that the pressure in cavity 40 decreases, while the pressure still persists in cavity 41, after check valve 42 has already before, when pressure equilibrium has been established in the cavity. the cavities 40, 41, cut off the communication between these cavities 40 and 41 under the inaction of the spring 44.

   At the same time that the cavities 40 are connected to the discharge lines, the cavities 69 are connected to the inflow of the pressurized liquid in the manner already described before, so that the pressure which builds up in it. the cavities 69 push the pistons 48 against the pistons 37, upwards (and to the left in FIG.

     3). During this movement of the piston 48, the axis 55 of the rod 47 moves forward in the slide groove 56 of the gripper jaw 33 and brings this jaw to the open position shown in Fig. 2, which has the effect of freeing the upper which is missed by this clamp. Temporarily the piston 37 of the pliers cannot yet rise, because there is still pressure in the cavity 41-above this piston.

   During the movement of the piston 48 upwards relative to the piston 37, the safety levers 60 return to their original position shown in FIG. 2, that is to say that they fall back into the grooves 62, and nothing further prevents - now the sheath 30 from being pushed downwards, if necessary with the clamps, which are now open , so that the piston 37 can descend to the withdrawal 155 of the closing nut 154 at the bottom of the working cylinder 27.



   'When the upper has been released by the clamps, they must immediately be brought back slightly downwards, so that they do not interfere with the work of the repellers and other devices for fixing the edges of the upper .



  The lowering movement of the open grippers is produced by

 <Desc / Clms Page number 28>

 
 EMI28.1
 the Ca110S 149 and 150 as a result of bones qu4 13 pistou? 4 is ra ..: ilené in its middle position (in .B'ig .. 5) and piston 75 in its marginal position of <!; dUCn. 8 (in 3iào 6).

   This has the consequence that the opening 30, which is connected to the civilians 40, and
 EMI28.2
 the opening 85 of the distributor spool are 1-1 <1- = àez, while the liquid under.! Î1BNiol1 L: nt1fJ via the inlet pipe 81 in the chamber 72 of the piston 75,, J, J, SSt ;;: lied: 11 t.Vie "lle: at 28 dee 'piston? 5 to arrive at the flow opening 83, through which it exits through the corresponding flexible pipes to enter the cavities 41 above the piston 37.

   On leaving the cavities 69 under the piston, the pressurized liquid arrives at the outlet. 82 by
 EMI28.3
 corresponding pipes, the opening 84, the channel 85, then by 1 greedily 89, the openings 91, the channel 92 and the valve 93 of the piston 75. This is why the pressurized liquid which is in the cavity 41 pushes the two pistons 37, 48 towards the
 EMI28.4
 down (c1a5t-à-dlc on the right in Fig. 3), until the downward movement of the clamps is stopped when the piston; 37 is applied to the removal of the nut 154 at the bottom of the working cylinder 27.



   When all the operations of the assembly machine are finished, the cams 149 and 150 finally cause again
 EMI28.5
 the return of the open clamps to their position ,, x'i: îitï'V8 ¯pax 'following the two pistons 74, 75 of the distribution spool allow the return to the right-hand marginal position in FIG. 4,
 EMI28.6
 position in which the cavities 40, 41 are connected "1 $ evacuaticn while the pressurized liquid enters, in the manner already de-
 EMI28.7
 written and passing through the voids 156 made in the rietrait 155 of the locking nut 154 at the bottom of the working ring 27, in the cavity 69, which is below the two pistons 37, 48 and advances these two piers to bring them to the starting position shown in FIG. 2.



  AT

 <Desc / Clms Page number 29>

 
After the clamps return to their starting position, the machine's work is finished and a special coupling automatically disengages the shaft drive device
 EMI29.1
 cams 141 after a turn of the arbree side B E S U M E The invention extends in particular to the following characteristics and their possible combinations.
 EMI29.2
 



  1 .- Drive device for stretching machines, spike-mounting machines and other uiizcliiwa for the abri- cation of shoes, serving to stretch the upper to mount it on a form by means (t'a set of tensioning pliers closing and opening. alternately and performing movements (traction and lateral movements, where appropriate, also a rotational movement around their own axis, as well as the $ movements of corresponding returns,

   device Characterized by a hydraulic control comprising differential pistons and a
 EMI29.3
 overflow valve has spring mounted between them, Ilenserabie cooperating so that, during the tensioning movement of the clamps, the tensile force exerted by them increases proportionally-
 EMI29.4
 ment to the increase in the resistance of the vamp, up to a determined maximum value, 1'-1'fort of 1'exiuetuxe of the jaws of the clamps increasing accordingly.
 EMI29.5
 



  2? .- The hydraulic clamping device of the clamps is constituted by a working cylinder comprising a hollow piston, which carries the fixed clamp jaw, while the movable jaw of the clamp is connected to a piston guided inside the clamp. the sleeve of the hollow piston.

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

3 .- An overflow valve mounted in a transverse wall of the hollow piston and communicating the cavity which is located above the hollow piston with the cavity which is <Desc / Clms Page number 30> located between the two working pistons * 4 .- The working cylinder is provided with three inlet pipes for the pressurized liquid, which is brought by one of these pipes above the hollow piston, by another between the two working pistons and then the third under these two, Pistons. 5 .- The opening and closing of the jaws of the grippers are caused by a relative movement of two pistons guided one in the other, pressurized liquid being introduced into the cavity which is located between these two pistons, then evacuated out of this cavity. 6 .- When the pressurized liquid is admitted inside delta, cavity between the two working pistons, the pressure which increases in this cavity after the closing of the jaws of the grippers causes the opening of the overflow valve, so that the liquid under pressure passes into the cavity which is located above the hollow piston and acts simultaneously from this cavity on the two working pistons. 7 .- The closing force of the jaws of the grippers depends, before the beginning of the tensioning movement of the grippers, '' on the load exerted by the spring of the overflow valve mounted on the path of the pressurized liquid which passes from the cavity between the working pistons into the cavity above (the these pistons. 8 .- After passing through the pressurized liquid which leaves the cavity between the working pistons to enter the cavity which is located above these pistons, the pressure prevailing in these two cavities increases, during the movement of tension of the grippers, proportional to the resistance of the workpiece, a predetermined maximum value being reached after the mounting of 1 upper on the form, so <Desc / Clms Page number 31> that the force of closing the jaws of the grippers increases at the same time. 9 '.' - The control of several grippers operating in the same way with respect to their phases of movement and time is ensured by means of a single distribution spool having two working chambers with their actuated pistons, on the one hand, by the worker, by means of a set of levers and, on the other hand, automatically by the machine by means of cams * 10 .- The adjustment of the distribution spool with a view to closing the jaws of the grippers and initiating the traction movement thereof is carried out by means of a control lever which adjusts the position of the pistons of the spool. distribution so that the liquid under pressure enters the cavity between the working pistons of the grippers, while the cavity which lies below these pistons is connected to the discharge, the work of the grippers being able to be interrupted at will at any moment by means of the control lever, and the grippers being able to be immobilized in the position qu '' they occupy momentarily or immediately brought back to their starting position, 11 .- The distribution spool pistons are fitted with safety elements that hold the two pistons after the action of the control lever is interrupted, in positions in which the pressurized liquid neither enters nor leaves the hydraulic control device of the grippers, so that the grippers remain in the position in which they were at the time of the interruption of the action of the control lever. ; 12 .- After the release of the safety elements of the immobilized pistons, either by means of the control lever or by the machine by means of cams, the pistons return to their starting position under the action of return springs, position <Desc / Clms Page number 32> in which the cavity which is located above the working pedestrians of the grippers, as well as the cavity between these pistons, are connected to the discharge of the pressurized liquid, so that this liquid escapes from these cavities, while it enters the cavities which are under the two working pistons of the clamps by pushing these pistons upwards, thus causing a new opening of the jaws of the grippers and the return of the grippers themselves to their starting position 13 .- The automatic drive of the distribution spool pistons is only activated by the machine, by means of cam plates, when the actual work, that is to say - the mounting of the vamp on the shape by means of the pliers, is finished, of aorta that the cams then automatically cause, by cooperating with other working operations of the assembly machine, such as shaping of the toe of the shoe, embossing and finally the fixing of the edge of the vamp, the opening of the jaws of the darts to free the edge of the vamp, the movements of spacing of the pincers downwards, so that these clamps do not interfere with the repellers or the '-' fixing device, as well as the return of the open clamps to their posi-. starting point. 14 .- The pressurized liquid pump is only exposed during the actual working operation, that is to say during the fitting of the toe (the shoe, only to peak pressures, pressures including the size is determined by the adjustment of a safety valve, while it is put on idle by means of a special slide, at the time of intermediate operations.