US3849943A - Power operated sanding machine - Google Patents

Abstract

A hand-manipulated sanding machine with a base plate on which is secured a backing pad for a sandpaper sheet. The base plate is carried on the machine housing by a plurality of one-piece mounting posts which are elastically deformable and detachably connected to the base plate by a bayonet-like connection. Sandpaper holders are pivotally mounted directly on base plate bearing portions and are biased into position by leaf springs.

Description

United States Patent [191 Thomas et al.

[ 51 Nov. 26, 1974 POWER OPERATED SANDING MACHINE Inventors: Robert A. Thomas, Shreveport, La;

Jerry Wayne Sellers, Lexington; Roger Wayne Morley, Medina, both of Tenn.

Rockwell International Corporation, Pittsburgh, Pa.

Filed: Feb. 26, 1973 Appl. No.: 335,929

[73] Assignee:

US. Cl. 51/170 MT Int. Cl 1324b 23/04, B24b 23/08 Field of Search 51/170 MT, 170 TL, 382,

References Cited UNITED STATES PATENTS 12/1956 Roods 51/170 MT 2,885,833 5/1959 Neff 51/170 MT 3,336,702 8/1967 Endersi... 51/170 MT 3,345,784 10/1967 Stelljesm. 51/170 MT 3,543,449 12/1970 Scott 51/170 MT 3,747,280 7/1973 Stroezel 51/170 MT Primary Examiner-Donald G. Kelly [57] ABSTRACT 14 Claims, 21 Drawing Figures Q a 40 i 54 64 52 5o n F 68 46 52 I ll r 1 I, l I i 92 l PATENTEL, M26 1974 SHEEH 2 BF 5 PATENTL 31172 81974 SHEEF 3 OF 5 PATENTE; .QGVZSISM 3, 9,9

SHEET u UF 5 FIG. 9

FIG. I0

PATENT E HJV 2 61974 SHEEF 5 [IF 5 FIG. I

POWER OPERATED SANDING MACHINE FIELD OF INVENTION This invention relates to power operated sanding machines and particularly to the portable type of sanding machines in which a motor driven pad assembly is suspended from the motor-receiving housing.

BACKGROUND Conventional power operated, portable sanders typically comprise a housing for receiving a drive motor and a pad assembly drive connected to the motor and suspended from the housing by four elastically deformable posts. The elastically deformable posts are deflectible to permit orbital or oscillating motion of the pad assembly relative to the motor-receiving housing. The pad assembly provides a backing for a sheet of sandpaper or abrading paper which is held in place by clamps on the pad assembly.

Examples of prior sanding machines are described in U.S. Pat. No. 3,345,784 issued to C. R. Stelljes et al on Oct. 10, 1967 for Orbital Finishing Sander, U.S. Pat. No. 3,267,622 to L. Frostad on Augf23, 1966 for Abrasive Pad Structure For Portable Sanding Machine, U.S. Pat. No. 3,546,822 issued to A. A. Hutchins on Dec. 15, 1970 for Clip For Surface Treating Tool, U.S. Pat. No. 3,336,702 issued to S. G. Enders on Aug. 22, 1967 for Oscillating Platen For Abrading Tool, U.S. Pat. No. 2,606,947 issued to R. Happe on Aug. 12, 1952 for Electric Motor For Sanding Tools Or The Like, U.S. Pat. No. 3,543,449 issued to W. H. Scott et al on Dec. 1, 1970 for Dual Motion Surface-Dressing Machine, U.S. Pat. No. 2,697,897 issued to D. l. Dickinson on Dec. 28, 1954 for Rubbing Machine, U.S. Pat. No. 2,893,174 issued to 1. Jepson on July 7, 1959 for Surface Treating Machine, U.S. Pat. No. 2,848,850 issued to B. G. Metoff on Aug. 26, 1958 for Electric Sanders, U.S. Pat. No. 3,555,743 issued to W. L. Geiger on Jan. 19, 1971 for Power Sander, U.S. Pat. No. 2,885,833 issued to G. M. Neff on May 12, 1959 for Hand Held Sanding and Abrading Machine, U.S. Pat. No. 3,418,761 issued to M. I. Sheps on Dec. 31, 1968 for Dual-Action Power Operated Abrading Tool, U.S. Pat. No. 3,375,616 issued to W. H. Scott et al on Apr. 2, 1968 for Dual Motion Surface-Dressing Machine, U.S. Pat. No. 3,199,251 issued to S. G. Enders on Aug. 10, 1965 for Driving Mechanism For Abrading Tool, U.S. Pat. No. 2,697,898 issued to R. T. Osman on Dec. 28, 1954 for Recurrent Motion Abrading Apparatus, U.S. Pat. No. 2,969,656 issued to S. G. Reuter on Jan. 31, 1961 for Coupling Device, U.S. Pat. No. 3,396,963 issued to A. A. Hutchins on Aug. 13, 1968 for Resilient Cushion Structure, U.S. Pat. No. 3,224,149 issued to E. M. Harrington et al on Dec. 21, 1965 for Hand Sander, U.S. Pat. No. 2,441,506 issued to R. T. Osman on May 1 1, 1948 for Recurrent Motion Abrader, U.S. Pat. No. 2,509,561 issued to A. J. Dremel on May 30, 1950 for Clip For Holding Sanding Paper, U.S. Pat. No. 2,749,679 issued to N. T. Anton on June 12, 1956 for Shoes For Rubbing Devices, and U.S. Pat. No. 2,764,852 issued to A. N. Emmons on Oct. 2, 1956 for Portable Power Operated Sanding Machine.

SUMMARY AND OBJECTS OF INVENTION As compared with the structures described in the foregoing patents, the present invention provides for a novel and simplified structure for suspending or supporting the pad-carrying base plate from the motor housing.

In the sanding machine of this invention, the posts for supporting the base plate are formed at their lower ends with coupling flanges that are adapted to be received and locked in sockets in the base plate. The upper ends of each pair of posts are integrally joined together by a spacer portion to define a one-piece mounting member that is formed from elastically deformable material. By torsionally deflecting the posts or flexing the spacer portions, or both, the coupling flanges are rotatable about the longitudinal axes of their posts to positions where they may be insertable into the sockets in the base plate. After the coupling flanges are seated in base plate sockets, the one-piece elastically deformable mounting member is relaxed to turn the coupling posts to locking positions where they engage portions of the base plate to thereby detachably couple the posts to the base plate for supporting the base plate from the posts.

With the foregoing summary in. mind, a major object of this invention is to provide a novel construction for supporting the base plate from the housing of the sanding machine.

Another and more specific object of this invention is to provide a novel structure for coupling the base platesupporting posts to the base plate.

According to another feature of this invention, the motor housing is longitudinally divided into a pair of separately formed shells having inwardly opening cavities that receive the spacer portions of each of the previously mentioned one-piece, dual-post mounting members. The spacer portions are trapped between the shells and are held in place only by separable seating surface engagement with the cavity-defining surfaces of the shells to thereby secure the upper ends of the base plate'supporting posts to the housing.

Thus, another object of this'invention is to provide a novel construction for securing the upper ends of the base plate-supporting posts to the housing.

Another and more specific object of this invention is to provide a novel sanding machine in which a plurality of mounting members for supporting the base plate are trapped between the shells of the longitudinally divided housing and are held in place only by separable seating surface engagement with interior surfaces of the shells.

From the foregoing it will be appreciated that the sanding machine of this invention requires no screws or other fasteners for securing the base plate-mounting posts to either the base plate or to the motor housing. The novel construction of this invention furthermore provides for the easy, simplified and quick assembly and disassembly of the posts.

According to still another feature of this invention, a novel clamping structure for securing sandpaper or the like to the pad assembly eliminates the need for a pivot pin. Heretofore, pivot pins supported on the base plate were utilized to pivotally mount the sandpaper clamps for movement between clamping and unclamping positions. According to this invention specially constructed clamps or paper holders are pivotally mounted directly on integral bearing portions of the base plate to eliminate the need for pivot pins or the like.

Thus, another object of this invention is to provide a novel construction for clamping; or holding sheets of sandpaper or other abrading paper on the pad assembly.

These and other objects of this invention will appear as the description proceeds in connection with the appended claims and below-described drawings.

DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of a power operated, hand sanding machine incorporating the principles of this invention;

FIG. 2 is a fragmentary side elevation showing the sander of FIG. 1 with one of the halves of the longitudinally split housing removed to illustrate internal parts of the sanding machine;

FIG. 3 is an interior side elevation of the right-hand half of the split housing shown in FIG. 1;

FIG. 4 is an interior side elevation of the left-hand half of the split housing shown in FIG. 1;

FIG. 5 is a plan view of one of the dual post mounting members shown in FIG. 2;

FIG. 6 is a front elevation of the mounting member shown in FIG. 5;

FIG. 7 is a side elevation of the mounting member shown in FIG. 5;

FIG. 8 is a fragmentary, perspective, partially exploded'view of the mounting member of FIG. 5 and the pad assembly;

FIG. 8A is a bottom plan view of the mounting member shown in FIG. 5;

FIGS. 9, 10, 11 and 12 are sections taken respectively along the lines 99, 10-10, 1111 and 12-12 of FIG. 2;

FIG. 13 is a section taken substantially along lines 13--13 of FIG. 2;

FIG. 14 is a view similar to FIG. 8, but showing one of the mounting posts torsionally deflected for inserting the locking flange on the bottom of the post into the flange-receiving socket in the base plate;

FIG. 15 is a rear elevation of the forward paper holder shown in FIG. 1;

FIG. 16 is a top plan view of the paper holder shown in FIG. 15;

FIG. 17 is a side elevation of the paper shown in FIG. 15;

FIGS. 18 and 19 are sections respectively taken substantially along lines 18-18 and l919 of FIG. 13; and

FIG. 20 is a view similar to FIG. 18, but showing the paper holder pivoted to a position where it is disengageable from the base plate.

DETAILED DESCRIPTION Referring now to the drawings and more particularly to FIGS. 1 and 2, the portable hand manipulatible, power driven sanding and abrading machine incorporating the principles of this invention is shown to comprise a hollow, longitudinally split, clam shell type housing or casing 20. Housing 20, as shown in FIG. 2, contains an electric motor 22 and an eccentric drive mechanism 23. Mechanism 23 drive connects motor 22 to a pad assembly 24 for imparting an orbital motion to pad assembly 24.

Pad assembly 24 comprises a rigid, rectangular backing shoe or base plate 25 and a resilient, flat-sided pad 26 of felt, elastically deformable yieldable material or the like. Pad 26 is fixed, as by bonding, to the underside of base plate 25. Pad assembly 24 is supported below or on the underside of housing 20 and is horizontal when the sander is held in such a position that the rotational axis of motor 22 is vertical.

Pad assembly 24 provides a backing for a sheet of sandpaper indicated at 28 in FIG. 2. The motion of pad assembly 24 resulting from energization of motor 22 is in a plane that is substantially normal to the rotational axis of motor 22.

Motor 22 may be of any conventional, suitable construction and, as shown in FIG. 2, comprises a stator 30 having field windings peripherally surrounding an armature 32. Armature 32 is mounted on an armature shaft 34 which extends coaxially through stator 30 and which is drive connected by mechanism 23 to to pad assembly 24 in a manner to be explained in greater detail later on.

With continued reference to FIGS. 1 and 2, housing 20 has a hollow body portion 38, a grip type handle 40 extending rearwardly from body portion 38, and a grippable knob portion 41 extending forwardly from body portion 38. Motor 22 and mechanism 23 are received in body portion 38. Handle 40 houses an electrical on-off switch 42 having a manually manipulatable switch actuator or trigger 44 for controlling operation of motor 22. Power is supplied to operate motor 22 through a conventional power cord 46 having conductors conventionally connected to switch 42 and motor 22 for supplying current under the control of switch 42.

As shown in FIG. 2, a commutator 50, forming a part of motor 22, is carried by shaft 34 and is electrically connected to armature 32 in the usual manner. Brush elements 52, which are spring biased into electrical contact with the commutator periphery, are mounted in electrically non-conductive brush holders 54.

Pad assembly 24 is supported on the underside of body portion 38 which opens downwardly from the position of the machine as shown in FIG. 2.

As shown in FIGS. 1, 3 and 4, housing 20 is longitudinally divided into two complementary shells and 62 to provide a clam shell type enclosure for the internal parts of the sander. Shells 60 and 62 are separately molded from a suitable electrically non-conductive plastic and have oppositely dished curvatures.

Shells 60 and 62 are respectively formed with mating longitudinal edge surfaces indicated at 64. Edge surfaces 64 seat against each other along a substantially planar interface that longitudinally and medially intersects body portion 38, handle 40, knob 41 and pad assembly 24. The rotational axis of shaft 34 lies substantially in a plane containing this interface. Machine screws 68 (see FIG. 2) extending through bores in shell 62 are threaded into tapped bores in shells 60 to firmly and rigidly secure shells 60 and 62 together.

Bearings 82 and 83 respectively journel the outboard and inboard ends of armature shaft 34. Stator 30, bearings 82 and 83, and brush holders 54 are all seated in mating, generally complementary cavities that are formed in shells 60 and 62 and that are generally indicated at 84 in FIGS. 3 and 4. There motor parts, namely the stator, the armature shaft bearings and the brush holders are all trapped in position between shells 60 and 62 and are confined only by separable seating surface engagement with the interior cavity defining surfaces of shells 60 and 62.

A fan 92 is fixed on shaft 34 axially between armature 32 and bearing 83. Rotation of fan 92 draws air in through openings 93 at the top of housing 20, causing the air to flow through and cool motor 22. The heated air is exhausted through openings 93a which are also formed through housing 20. The hub of fan 92 is axially confined between the downwardly directed face of armature 32 and an annular spacer 94.

Mechanism 23, which may be of any suitable conventional construction, may correspond to the construction described in US. Pat. No. 3,345,784. As shown in FIG. 2, mechanism 23 comprises a flexible coupling 99 and an eccentric 100 having a hub portion 102 that is journalled in a roller bearing 104. A bore 108, which is formed through hub portion 102, is eccentric to the outer cylindrical periphery of hub portion 102 which engages and is coaxial with the inner race of bearing 104. Bearing 104 is coaxially seated in an upwardly opening cylindrically contoured socket 110 which is integrally formed in base plate 25.

Coupling 99 may be the same as that described in US. Pat. No. 3,345,784 and comprises an elastically deformable flexible member 120 and a pair of threaded stud members 122 and 124 that are interconnected by flexible member 120. Member 122 is threaded into the lower end of shaft 34, and member 124 is threaded into bore 108.

From the foregoing construction of mechanism 23, it will be appreciated that mechanism 23 will cause pad assembly 24 to orbit about the axis of shaft 34 upon energization of motor 22.

In accordance with one feature of this invention, pad assembly 24 is secured to housing only by a pair of specially constructed, elastically deformable, one- piece members 150 and 151 to permit orbital, oscillatory or reciprocatory displacement of pad assembly 24 relative to housing 20. Members 150 and 151 may be formed,

as by molding, from any suitable, yieldable, elastically deformable or elastomeric material such as rubber. Members 150 and 151 suspend pad assembly 24 from housing 20 as shown.

Referring to FIGS. 5-8, member 150 comprises a pair of spaced apart, solid cylindrical posts 154 and 156 and a flat-sided spacer or bridging portion 158 that integrally joins the upper ends of posts 154 and 156 together. When spacer portion 158 is straight as shown in FIGS. 58, posts 154 and 156 are in coextensive, parallel spaced apart relation with each other. Spacer portion 158 bridges the space between posts 154 and 156 and is sufficiently thin to allow it to be easily flexed and twisted in the region between posts 154 and 156.

As shown in FIGS. 6, 8 and 8A, post 154 terminates in a coupling foot or flange 160 of generally rectangular configuration. Adjacent to its lower end, post 160 is coaxially formed with a further flange 162 that is spaced by a short axial distance from foot 160. The outer periphery of flange 162 is uniformly diametered. The bottom of foot 160 is flat and in a plane normally intersecting the longitudinal axis of post 154.

Foot 160 is elongated in the direction in which spacer portion 158 is elongated. Foot 160 and flange 162 cooperate to define two radially outwardly opening, circumferentially spaced apart grooves 164 and 166 on diametrically opposite sides of post 154. The edges 168 and 169 (FIG. 8A) at the opposite ends of foot 160 are of segmental circular contour.

Posts 154 and 156 are substantially identical. Accordingly, like reference numerals suffixed by the letter a have been applied to designate like portions of post I In its undeformed, relaxed condition, mounting member is symmetrical about a plane medially intersecting spacer portion 158 and containing the longitudinal axes of posts 154 and 156. Mounting member 150 also is symmetrical about a plane that medially and perpendicularly intersects spacer portion 158.

Posts 154 anad 156 depend from spacer portion 158 adjacent to the opposite ends of spacer portions 158. The diameters of posts 154 and 156 are somewhat smaller than the width of spacer portion 158.

As shown in FIGS. 2 and 10, mounting member 151 is identical to and interchangeable with mounting member 150. Accordingly, like reference numerals, but primed, have been applied to designate corresponding portions of mounting member 151.

Near the forward wall of housing 20, shells 60 and 62 are respectively formed with opposed, complementary cavities (FIG. 3) and 182 (FIG. 4) that open toward each other to interfittingly and slidably receive spacer portion 158. The housing wall surfaces defining the top and bottom of cavities 180 and 182 are flat and parallel. The wall defining the bottom surface of cavity 180 is formed with an inwardly opening slot 184 (FIGS. 3 and 11). The wall defining the bottom of cavity 182 is similarly formed within an inwardly opening slot 186 (FIG. 4). Slots 184 and 186 are complementary, opposed and open toward each other. Posts 154 and 156 extend transversely through slots 184 and 186 respectively.

Cavities 180 and 182 terminate at the interface be tween shells 60 and 62. Thus, the half of spacer portion 158 extending between one end thereof and a plane medially and normally intersecting spacer portion 158 is received in cavity 180, while the remaining of half of spacer portion 158 is received in cavity 182. The dimension of the combined cavity region defined by cavities 180 and 182 is just enough to accommodate spacer portion 158 so that transverse movement of mounting member 150 relative to housing 20 is precluded by abutment of the opposite ends of spacer portion 158 with the closed end wall regions of cavities 180 anad 182. Movement of mounting member 150 in a direction extending longitudinally of housing 20 is precluded by abutment of the forwardly and rearwardly facing edges of spacer portion 158 with opposing wall surfaces of cavities 180 and 182.

The widths of slots 184 and 186 are equal and just large enough to accommodate posts 154 and 156. As the result, the bottom wall portions defining cavities 180 and 182 seat against the downwardly facing marginal edge regions of spacer portion 158 to provide a support therefor. Seating engagement of spacer portion 158 with the top and bottom wall portions defining cavities 180 and 182 prevent spacer portion 158 from flexing or twisting in cavities 180 and! 182.

In assembled relation with housing 20, spacer portion 158 extends transversely of housing 20 closing adjacent to the front wall portion 188 (FIG. 2) of housing 20. Spacer portion 158 is closely parallel to and spaced vertically above base 25. Cavities 180 and 182 locate mounting member 150 in such a manner that the lower ends of posts 154 and 156 are positioned at the two front corners of base 25 as best shown in FIG. 13.

Adjacent to the rearwardly facing wall of housing 20, which is indicated at 190 in FIG. 2, shells 60 and 62 are respectively formed with opposed, complementary cavities 192 (FIG; 3) and 194 (FIG. 4) that open toward each other to slidably and interfittingly receive spacer portion 158 in the same manner that spacer portion 158 is received in cavities 180 and 182. The bottom walls defining cavities 192 and 194 are respectively formed with opposed, inwardly opening slots 196 (FIGS. 3 and 12) and 198 (FIG. 4) that open toward each other.

The arrangement and construction of cavities 192 and 194 together with their slots 196 and 198 are substantially the same as cavities 180 and 182 and slots 184 and 186. The assembly of spacer portion 158' in cavities 192 and 194 is the same as that described for spacer portion 158 and cavities 180 and 182. Cavity 192 receives the half of spacer portion 158' extending from one end thereof to a plane medially intersecting spacer portion 158, and the remaining half of spacer portion 158 is received in cavity 194. Posts 154' and 156' respectively extend transversely through slots 196 and 198 in the same manner as described with regard to posts 154 and 156 and slots 184 and 186. Spacer 158' is confined in cavities 192 and 194 in the same manner that spacer 158 is confined in cavities 180 and 182.

Cavities 180, 182, 192 and 194 are formed in those regions of shells 60 and 62 that define body portion 38. Cavities 180, 182, 192 and 194 are at a level below stator 30 as shown.

Cavities 192 and 194 locate mounting member 151 in such a manner that the lower ends of posts 154 and 156' are respectively at the two rearward corners of base 25 adjacent to rear wall 190. The lower ends of posts 154, 156, 154' and 156 extend through and beyond the open bottom of housing 20.

Spacer portions 158 and 158 are each confined and trapped in place between interior surfaces of shells 60 p and 62 solely by separable seating surface engagement with the interior shell surfaces that define cavities 180, 182, 192 and 194. Spacer portions 158 and 158 are thus trapped in place between shells 60 and 62 when the shells are secured together to thereby secure mounting members 150 and 151 to housing 20 at the upper ends of posts 154, 156, 154 and 156'. From this description it will be appreciated that mounting members 150 and 151 are not secured to housing 20 by fasteners and, instead, are trapped in place only by separable seating surface engagement with interior surfaces of shells 60 and 62.

In assembled relation, spacer portion 158 and 158' are spaced apart in substantially coextensive, parallel relation. A plane containing either the top surfaces of spacer portions 158 and 158 or the bottom surfaces of spacer portions 158 and 158 substantially normally intersects the rotational axis of shaft 34. The rotational axis of shaft 34 is substantially normal to base 25 and to the bottom flat surface of pad 26.

Referring to FIG. 13, base plate 25, which may be molded from a suitable plastics material, is formed with four apertures or holes 200, 201, 202 and 203. Apertures 200-203 are respectively disposed at the four corners of base 25 and extend through base plate 25 along parallel spaced apart axes.

Referring to FIGS. 8 and 9, the upper and lower end portions of apertures 200 are circular and uniformly diametered. These upper and lower end portions of aperture 200 are respectively indicated at 206 and 208 in FIG. 9 and are axially aligned. The mid-portion of aperture 200, which extends axially between end portions 206 and 208, is indicated at 210 in FIGS. 8 and 9 and is non-circular as best shown in FIG. 8. Mid-portion 210 is defined in part by inwardly extending shoulder 212 and 214 (FIG. 9) that provides mid-portion 210 with a generally rectangular configuration that corresponds to foot 160. Shoulders 212 and 214 are circum ferentially spaced apart on diametrically opposite sides of aperture 200.

From the foregoing it will be appreciated that aperture portions 206, 208 and 210 respectively form axially aligned sockets 215 and 216 that are axially separated by shoulders 212 and 214. Socket 215 is defined by the smooth cylindrical peripheral wall of portion 206 and by shoulders 212 and 214. Socket 216 is defined by the smooth cylindrical peripheral wall of portion 208 and by shoulders 212 and 214.

Apertures 2111-203 are the same as aperture'200. Accordingly like reference numerals suffixed by the letter a have been applied to designate like portions of aperture 201, like reference numerals suffixed by the letter b" have been applied to designate like portions of apertures 202, and like reference numerals suffixed by the letter c have been applied to designate like portions of aperture 203.

In the assembled relation of mounting'members and 151 and base plate 25, the lower ends of posts 154, 156, 154 and 156 extend into apertures 200-203 respectively. Foot 160 and flange 162 are respectively received in sockets 215 and 216, and the shoulders 212 and 214 of aperture 200 extend into grooves 164 and 166 so that the two end portions of foot 160 that extend in diametrically opposite directions beyond the adjacent region of post 154 underlie and seat against the undersides of shoulders 212 and 214. In this manner shoulders 212 and 214 are engaged by foot 160 and flange 162 to interlock post 154 and base 25 and to thereby detachably secure or couple the lower end of post 154 to base plate 25. It will be appreciated that the coupling of the lower end of post 154 to base plate 25 is only by separable seating surface engagement of flange 162 and foot 160 with the base plate surfaces defining sockets 215 and 216.

The fit of shoulders 212 and 214 in grooves 164 and 166 is snug. The radii of edges 168 and 169 is closely equal to the diameter of socket 216 so that foot 160 snugly seats in socket 216. Also, flange 162 snugly and interfittingly seats in socket 215.

The manner in which the lower ends of posts 156, 154' and 156' are mounted in apertures 201-203 is the same as that just described for post 154 and aperture 200. Thus, as shown in FIGS. 9 and 10, foot 160a seats in socket 216a, flange 162a seats in socket 215a, shoulders 212a and 2140 in grooves 166a and 168a, foot 160' seats in socket 216b, flange 160 seats in socket 215b, shoulders 21212 and 214b seat in grooves 166' and 168', foot 160a seats in socket 216e, flange 162a seats in socket 215C, and shoulders 212e and 214e seat in grooves 166a and 168a.

From the foregoing description it will be appreciated that the lower ends of posts 154, 156, 154 and 156 are detachably coupled to base plate 25 only by separable seating surface engagement with base plate 25. Mounting members 150 and 151 are therefore not secured to base plate 25 by fasteners of any kind.

From FIGS. 8, 9, 10 and 13, it will be observed that the generally rectangular mid-portions 210, 210a, 21Gb and 2111c of apertures 200203 are each elongated in a direction extending longitudinally of the sander as indicated by axis A-A in FIG. 8, whereas feet 160, 160a, 160' and 160a are each elongated along an axis B-B (See FIG. 8) that extends transversely of the sander and at right angles to the elongation axes A-A when mounting members 150 and 151 are relaxed and undistorted.

To couple post 154 with base plate 25, foot 160 is turned through an angle of approximately 90 by torsionally deflecting post 154 (See FIG. 14) and/or by flexing spacer portion 158 to align foot 160 with midportion 211) in such a manner that its axis of elongation B--B extends in the same direction as is and parallel to axis A-A. Foot 160 then may be pushed axially through mid portion 210 to seat in socket 216. Member 150 is then relaxed to its undeformed condition to rotate foot 160 to a locking position where it underlies shoulders 212 and 214 and where axis A-A is essentially at right angles to axis B-B.

Post 156, 154 and 156 are coupled to base plate 25 in the same manner just described for post 154. Posts 154, 156, 154' and 156 flex or resiliently yield to allow orbital or oscillatory motion of pad assembly 24 relative to housing 20.

To detach pad assembly 24 from mounting members 150 and 151, the mounting posts and/or spacer portions are deformed to turn each coupling foot to a position where its axis AA is parallel to axis 8-8. The foot of each post may then be pulled out of its associated aperture to disconnect it from base plate 25.

From the foregoing description, it will be appreciated that foot 160 and socket 216 provide a bayonet like connection for detachably securing the lower end of post 154 to base plate 25. Foot 160 is turnable or rotatable in socket 216 between and a locking position where its end portions underlie shoulders 212 and 214 and an unlocking position where it clears shoulders 212 and 214. Likewise, foot 160a and socket 216a provide a bayonet like connection for detachably securing the lower end of post 156 to base plate 25, foot 160 and socket 216b provide a bayonet like connection for detachably securing post 154 to base plate 25, and foot 160a and socket 216c provide a bayonet-like connection for detachably securing post 156 to base plate 25. Each of the feet 1600, 160 and 160a is rotatable in its socket between locking and unlocking positions in the manner just described for foot 160.

Because of the manner in which members 150 and 151 are secured to or interlocked with housing and base and because no fasteners are required for securing posts 154, 156, 154' and 156 to housing 20 or base plate 25, the assembly and disassembly of parts for yieldable supporting pad assembly 23 from housing 20 is simplified, easy and quick. Lubricant maybe applied to members 150 and 151 to further ease the assembly of members 150 and 151 with shells 60 and 62 and base plate 25.

A longitudinal plane containing the axis of shaft 34 and normally intersecting pad assembly 24 medially and normally intersects spacer portions 158 and 158. Posts 154, 154, 156 and 156 are symmetrical located relative to this plane, two being located on one side of the plane and two being located on the opposite side of the plane. This plane also passes substantially through the interface between shells 60 and 62.

It will be appreciated that the present invention thus far described may be utilized in conjunction with other abrading machines in which motion of the pad assembly or base plate is other than orbital.

As shown in FIGS. 1, 2 and 8, the sander of this invention is provided with a pair of sandpaper or abrading paper holders or clamping members 230 and 232. Holders 230 and 232 are pivotally mounted directly on base 25 at the front and rear ends of the sander for clamping the sandpaper or abrading paper in place on pad assembly 24.

Holder 230 is a one piece member and is formed, as by stamping, from a flat-sided metal plate. As shown in FIGS. 1, 2, 8 and 15-17, holder 230 comprises a flatsided, generally rectangular body or clamping portion 234 and a pair of parallel, flat-sided, spaced apart earlike pivot portions 235 and 236. Clamping portion 234 is integral with and extends between pivot portions 235 and 236. Pivot portions 235 and 236 extend from the opposite side edges of clamping portion 234 and are bent back to extend at right angles from clamping portion 234.

.The bottom edge of each of the pivot portions 235 and 236 is formed with an arcuate, downwardly opening notch 238. Base plate 25 is integrally formed with a pair of upwardly extending, spaced apart bearing portions 240 and 242 (see FIG. 13) that respectively seat in and extend through the notches 238 of pivot portions 235 and 236.

Pivot portions 235 and 236 are coextensive and are provided with substantially identical configurations. The longitudinal axes of the notches 238 in portions 235 and 236 are axially aligned.

Bearing portions 240 and 242 have corresponding configurations, are adjacent to the front edgeof base plate 25, and protrude upwardly from the top flat surface region of the base plate. As shown in FIGS. 18 and 19, the upper ends of bearing portions 240 and 242 are smoothly curved to interfit with notches 238.

Preferably, the curved ends of bearing portion 240 and 242 that seat against the arcuate edges of notches 236 and substantially uniformly diametered, and the arcuate edges of notches 238 that seat on the curved ends of bearing portions 240 and 242 are also substantially uniformly diametered to provide for smooth pivotal motion of holder 230 about the axially aligned pivot axes of the curved end regions of bearing portions 240 and 242.

At the mouth of the notch 238 in pivot portion 235, portion 235 terminates in a finger 244 (see FIGS. 17 and 18) that curves back toard clamping portion 234 and that extends into a slot or narrow hole 246 in bearing portion 240. Pivot portion 236 terminates in a similar finger 248 (FIG. 19) at the mouth of its notch 238, and finger 248 similarly extends into a slot or narrow hole 250 in bearing portion 242. The ends of fingers 244 and 248 delimit the mouths of the notches 238 in pivot portions 235 and 236.

As shown in FIGS. 2, 15 and 17, the bottom of body portion 234 terminates a straight-edged paper clamp ing lip 252 that is bent back towards fingers 244 and 248. Lip 252 extends parallel to the pivot axis of holder 230 and is spaced from fingers 244 and 248 so that the end of lip 252 delimits the mouths of notches 238 in pivot portions 235 and 236. Hence, the mouth of the notch 238 in pivot portion 235 is delimited by finger 244 and lip 252, and the mouth of notch 238 in pivot portion 236 is delimited by finger 248 and lip 252.

The spacing between the end of lip 252 and the end of each of the fingers 244 and 248 is less than the widths of bearing portions 240 and 242. Only the thickness or height of each of the bearing portions 240 and 242 extending vertically between its upper end and the upper end of its slot 246, 250 is less than the spacing between lip 252 and each of the fingers 244 and 248. With this construction, it is necessary to pivot or rotate holder 230 clockwise (as viewed from FIG. 2) to the position shown in FIG. where body portion 234 is approximately or almost parallel with and overlies base plate in order to disengage holder 230 from base plate 25. When body portion 234 is approximately or almost parallel with base plate 25, the mouths of notches 238 will face forwardly to receive the bearing portion regions extending between slots 246 and 250 and the upper ends of bearing portions 240 and 242, thus permitting disengagement of holder 230 by moving it relative to base plate 25 and toward the rotational axis of motor 22.

When holder 230 is in any other position where body portion 234 is not approximately or almost parallel to base plate 25, it cannot be disengaged from bearing portions 240 and 242 because fingers 244 and 248 will butt against the upper wall regions of slots 246 and 250.

In order to rotate holder 230 to its position where it is disengageable from bearing portions 240 and 242 it is first necessary to remove mounting member 150 and a leaf spring 254. Spring 254 biases holder 230 in a counterclockwise direction (as viewed from FIG. 2) to its illustrated, upright paper-clamping position where body portion 234 is closely perpendicular to base plate 25. In this clamping position, holder 230 is angularly spaced from its position where it is disengageable from bearing portions 240 and 242 by a magnitude approaching 90.

As viewed from FIG. 2, counterclockwise rotation of holder 230 is limited by abutment of lip 252 with the flat vertical front surface of a straight ridge portion 256. Ridge portion 256 is integral with base plate 25 and extends across the front of base plate 25 at right angles to the straight parallel sides of the base plate. Bearing portions 240 and 242 protrude upwardly from ridge portion 256. I

At its forward end, base plate 25 terminates in a ledge portion 258. Ledge portion 258 projects forwardly beyond ridge portion 256 and is perpendicular to ridge portion 256 to define a stepped region over which the sandpaper is folded. In particular, the forward end of the sandpaper sheet 28 is folded up over the forward edge of ledge portion 258, then back over the horizontal surface of ledge portion 258 and finally up between lip 252 and the vertical front face of ridge portion 256. The end of the sandpaper sheet is clamped between lip 252 and the front face of ledge portion 256, and spring 256 biases holder 230 to its clamping position where it seats against the sandpaper sheet.

As shown in FIG. 2, the end portion of spring 254/remote from holder 230 is separably seated in shallow, interfitting, upwardly opening recess 260 that is formed in the top surface of base plate 25. The region of spring 254 between recess 260 and its end that seats against holder 230 is flexed upwardly from base plate 25 as shown.

The end of spring 254 remote from recess 260 seats against an arcuate tab 262 which is integral with the body portion 234 of holder 230. Tab 262 is formed in body portion 234 by parallel spaced apart cuts extending from the upper edge of body portion 234. The curvature of tab 262 provides for the application of the spring force in such a direction that holder 230 is biased in a counterclockwise direction (as viewed from FIG. 2) to its paper clamping position. A bridge portion 263, which is integral with base plate 25, crosses over spring 254 at the forward end of recess 260 to keep spring 254 from snaping out of the recess.

To remove an old sheet of sandpaper or to mount a new sheet on pad assembly 24, holder 230 is rotated in a clockwise direction as viewed from FIG. 2 to move lip 252 away from ridge portion 256. In this paperunclamping position, holder 230 is still angularly spaced by a significant magnitude from its position where it is disengageable from bearing portions 240 and 242. Thus, the operative clamping and unclamping positions of holder 230 are angularly spaced by significant distances from the position where holder 230 is disengageable from base plate 25. Furthermore, holder 230 cannot be pivoted back towards motor 22 and to its position where it is disengageable from base plate 25 without first removing mounting member 150. It will be appreciated that the unclamping position of holder 230 is angularly spaced between its clamping position and its position where it is disengageable from base plate 25.

A pair of ears (see FIG. 13), which are integral with bearing portions 240 and 242, extend between and are abuttable against pivot portions 235 and 236 to confine holder 230 against motion along its pivot axis.

The construction of holder 232 is the same as the construction of holder 230. Accordingly, like reference numerals suffixed by the letter a have been applied to designate corresponding portions of holder 232. Holders 230 and 232 are interchangeable. Holder 232 is pivotally mounted directly on the base plate 25 in the same manner just described from for holder 230. Holder 232 is at the rearward end of base plate 25 for clamping the rear edge portion of the sandpaper sheet 28. The base plate construction for mounting holder 232 and for clamping the rearward edge of sheet 28 is the same as that just described for mounting holder 230 and for clamping the forward edge of sheet 28. Accord ingly, like reference numerals suffixed by the letter a have been applied to designate the corresponding base plate portions that are associated with holder 232. These portions include bearing portions 240a and 242a which correspond to bearing portion 240 and 242, ridge portion 256a which corresponds to ridge portion 256 and ledge portion 258a which corresponds to ledge portion 258.

A spring 254a biases holder 232 in a clockwise direction (as viewed from FIG. 2) to its paper clamping position. Spring 254a is of the same construction and is interchangeable with spring 254. The base plate construction for mounting spring 254a is the same as that described for spring 254. This includes the shallow recess 260a and the bridging portion 263a which respectively corresponds to recess 260 and bridging portion 263. Ridge portions 256 and 256a are parallel as shown.

Base plate is symmetrical about a plane containing the axis of socket 110 and perpendicularly intersecting the base plate in parallel relation with ridge portions 256 and 256a.

From the foregoing it will be appreciated that holder 23b is hinged directly on base plate 25 by engagement of pivot portions 235 and 236 with bearing portions 240 and 242. Similarly, holder 232 is hinged directly on base plate 25 by engagement of pivot portions 235a and 236a with bearing portions 240a and 242a. As a result, the need for separate pivot pins or the like is eliminated with the construction of this invention. Holders 230 and 232 are pivotable about parallel spaced apart axes.

Holder 232 is disengageable from bearing portions 240a and 242a in the same manner as described for holder 230. Mounting member 151 must first be removed in order to permit holder 232 to be pivoted to its disengaging position where body portion 234a is approximately or almost parallel with base plate 25.

As shown in FIG. 2, the rearward end of sandpaper sheet 28 is folded back over ledge 248a and then up between ridge portion 246a and lip 252a.

The sander of this invention may be assembled and disassembled in different ways. One way of assembly is to mount holders 230 and 232 and springs 254 and 254a in place on base plate 25. The sub-assembly of motor 22 and mechanism 23 may be mounted on base plate 25 before or after the mounting of holders 230 and 232. Next, mounting members 150 and 151 are mounted on base plate 25, and finally shells 60 and 62 are mounted in place and fastened together by screws 63.

Spacer portions I58 and 158' are sufficiently thin to enable posts 154, 156, 154 and 156 to be rotated about their longitudinal axes by flexing or deforming spacer portions 158 and 158. Thus, when shells 60 and 62 are disassembled from mounting members 150 and 151, coupling feet 160, 160a, 160 and 160a may be turned or rotated to either their coupling or uncoupling positions simply by flexing or deforming spacer portions 153 and 158'.

Holders 230 and 232 are rigid one-piece members and do not flex as they are pivoted between their clamping and unclamping positions.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. In a handmanipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate and providing a backing for a sheet of sandpaper, means comprising a motor supported by said housing for imparting motion to the assembly of said base plate and said pad, a plurality of posts carried by said housing for suspending said base plate from said housing, said posts being formed from elastically deformable material to permit motion of said base plate relative to said housing by operation of said motor, and cooperating means on said base plate and the lower end of each of said posts for providing a detachable bayonet like connection between said base plate and the lower end of each post.

2. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate to provide a backing for a sheet of sandpaper, means comprising a motor supported by said housing for imparting motion to the assembly of said base plate and said pad, a plurality of one-piece mounting members carried by said housing for supporting said base plate from said housing, said mounting members being formed from elastically deformable material to permit motion of said assembly relative to said housing by operation of said motor, each of said mounting members comprising a pair of spaced apart posts and a spacer portion integrally joined to said posts at corresponding ends thereof, and cooperating means integral with said base plate and each of said posts at the end thereof opposite from the spacer portion for providing a detachable bayonet-like connection between said base plate and each of said posts.

3. The handmanipulatable, poweroperated sanding machine defined in claim 2 wherein said housing comprises a pair of separately formed shells, and wherein means are provided for securing said shells together, said spacer portion of each mounting member being received in cavities formed in said shells and being trapped in place between interior surfaces of said shells.

4. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate to provide a backing for a sheet of sandpa per, means comprising a motor supported by said housing for imparting motion to the assembly of said base plate and said pad, at least one mounting member carried by said housing for supporting the assembly of said base plate and said pad from said housing, said mounting member being formed from elastically deformable material to permit motion of said assembly relative to said housing by operation of said motor, said mounting member having a pair of posts and a spacer portion extending between and joined to said posts at corresponding ends thereof, a coupling portion positioned on the end of each post opposite from said spacer portion, a coupling structure for each post, each coupling structure being positioned on said base plate for engagement with an associated one of said coupling portions to de tachably couple said base plate to said posts, each coupling portion being disengageable from its associated coupling structure by rotational deformation of said mounting member to uncouple said base plate from said posts.

5. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate to provide a backing for a sheet of sandpaper, means comprising a motor in said housing for imparting motion to the assembly of said base plate and said pad, first and second mounting members carried by said housing for supporting said assembly from said housing and formed from elastically deformable material to permit motion of said assembly relative to said housing by operation of said motor, each of said mounting members comprising a pair of posts, a spacer portion extending between and integrally joined to said posts at corresponding ends thereof, and a coupling portion integral with each post, said base plate being integrally formed with a coupling structure for each of said posts, each coupling structure being positioned to engage an associated one of said coupling portions to detachably couple said base plate to said posts, and each coupling portion being disengageable from its associated coupling structure by rotational deformation of its associated mounting member for uncoupling said base plate from said posts.

6. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate to provide a backing for a sheet of sandpaper, means comprising a motor supported by said housing for imparting motion to the assembly of said base plate and said pad, first and second mounting members carried by said housing for supporting said assembly from said housing and formed from elastically deformable material to permit motion of said assembly relative to said housing by operation of said motor, each of said mounting members comprising a pair of posts, a spacer portion extending between and integrally joined to said posts at corresponding ends thereof, and a coupling portion integral with each post at the end thereof opposite from its associated spacer portion, said base plate being integrally formed with a coupling structure for each of said posts, each coupling structure being positioned to engage an associated one of said coupling portions to detachably couple said base plate to said posts, and each coupling portion being disengageable from its associated coupling structure by torsional deflection of its associated post or by flexing its associated spacer portion to uncouple said base plate from said posts.

7. The hand-manipulatable, power-operated sanding machine defined in claim 6 wherein each coupling portion comprises a coupling flange that is rotatable from a coupling position to an uncoupling position that is angularly spaced from said coupling position by torsion ally deflecting its associated post or by flexing its associated spacer portion, and wherein each coupling structure comprises a pair of shoulders positioned in a hole that is formed in said base plate for each coupling flange, said coupling flange being insertable into its associated hol-e beyond said shoulders when in said uncoupling position, and said coupling flange being engaged with the undersides of said shoulders when it is rotated within its associated hole to said coupling position.

8. The hand-manipulatable, power-operated sanding machine defined in claim 6 wherein said housing is longitudinally divided into a pair of separately formed shells, wherein means are provided for securing said shells together, wherein the spacer portion of each of said mounting members is trapped between said shells, and wherein said shells have wall portions that engage the spacer portion of each of said mounting members to prevent flexure of said spacer portions in the assembled relation of said shells with said mounting members.

9. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate and providing a backing for a sheet of sandpaper, means comprising a motor in said housing for imparting motion to the assembly of said base plate and said pad, a plurality of torsionally deflectible posts of elastically deformable material supported at corresponding ends from said housing, each of said posts being integrally formed with a coupling portion, each coupling portion being rotatable from a coupling position to an uncoupling position that is angularly spaced from said coupling position by torsional deflection of its associated post, said base plate being integrally formed with a coupling structure for each of the coupling portions, each coupling portion being engaged with its associated coupling structure when in said coupling position to couple said posts to said base plate, and each coupling portion being disengaged from its associated coupling structure when in said uncoupling position to uncouple said posts from said base plate.

10. In a hand-manipulatable, power-operated sanding machine, a housing having a body portion, a pad assembly providing a backing for a sheet of sandpaper, a plurality of one-piece members of elastically deformable material suspending said pad assembly from said body portion to permit motion of said pad assembly relative to said housing, means comprising a motor in said housing for imparting motion to said pad assembly, at least said body portion of said housing being divided longitudinally into a pair of separately formed shells, and means securing said shells together, corresponding ends of said one-piece members being trapped between said shells and being held in place only by separable seating surface engagement with interior surfaces of said shells.

11. The hand-manipulatable, power-operated sanding machine defined in claim 10 wherein each of said one-piece members comprises a pair of spaced apart posts having their upper ends received in said body portion and a spacer portion integrally joined to the upper ends of said posts within said body portion, the lower ends of said posts being secured to a part of said pad assembly.

12. In a hand-manipulatable, power-operated sanding machine, a housing having a body portion, a pad assembly providing a backing for a sheet of sandpaper, first and second mounting members of elastically de forrnable material for suspending said pad assembly from said housing and permitting relative motion be tween said pad assembly and said housing, each of said mounting members comprising a pair of posts connected at corresponding ends to said pad assembly and a spacer portion integrally joined to and extending between said posts at the opposite ends thereof, at least said body portion of said housing being longitudinally divided into a pair of separately formed shells having a first pair of inwardly opening cavities and a second pair of inwardly opening cavities spaced from said first pair of cavities, and means securing said shells together, the spacer portion of said first member being received in the cavities of said first pair of cavities and being held in place only by separable seating surface engagement with interior cavity-defining surfaces of said shells, and said spacer portion of said second member being received in the cavities of said second pair of cavities and being held in place only by separable seating surface engagement with interior cavity-defining surfaces of said shells.

13. In a hand manipulatable, power operated sanding machine, a base plate of rectangular configuration, a pad secured to said base plate to provide a backing for a sheet of sandpaper, drive means for imparting motion to the assembly of said base plate and said pad, a pair of sandpaper holders, said base plate being integrally formed with at least one bearing portion for each of said sandpaper holders, and each sandpaper holder being pivotally mounted directly on its associated bearing said holders to their sandpaper-clamping positions, said spring means comprising a flat-sided leaf spring for each of said holder, each leaf springbeing seated at one end thereof in a shallow recess in said base plate, and the other end of each leaf spring being seated against a portion of its associated holder.

l= l l k

Claims (14)

1. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate and providing a backing for a sheet of sandpaper, means comprising a motor supported by said housing for imparting motion to the assembly of said base plate and said pad, a plurality of posts carried by said housing for suspending said base plate from said housing, said posts being formed from elastically deformable material to permit motion of said base plate relative to said housing by operation of said motor, and cooperating means on said base plate and the lower end of each of said posts for providing a detachable bayonet like connection between said base plate and the lower end of each post.

2. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate to provide a backing for a sheet of sandpaper, means comprising a motor supported by said housing for imparting motion to the assembly of said base plate and said pad, a plurality of one-piece mounting members carried by said housing for supporting said base plate from said housing, said mounting members being formed from elastically deformable material to permit motion of said assembly relative to said housing by operation of said motor, each of said mounting members comprising a pair of spaced apart posts and a spacer portion integrally joined to said posts at corresponding ends thereof, and cooperating means integral with said base plate and each of said posts at the end thereof opposite from the spacer portion for providing a detachable bayonet-like connection between said base plate and each of said posts.

3. The hand-manipulatable, power-operated sanding machine defined in claim 2 wherein said housing comprises a pair of separately formed shells, and wherein means are provided for securing said shells together, said spacer portion of each mounting member being received in cavities formed in said shells and being trapped in place between interior surfaces of said shells.

4. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate to provide a backing for a sheet of sandpaper, means comprising a motor supported by said housing for imparting motion to the assembly of said base plate and said pad, at least one mounting member carried by said housing for supporting the assembly of said base plate and said pad from said housing, said mounting member being formed from elastically deformable material to permit motion of said assembly relative to said housing by operation of said motor, said mounting member having a pair of posts and a spacer portion extending between and joined to said posts at corresponding ends thereof, a coupling portioN positioned on the end of each post opposite from said spacer portion, a coupling structure for each post, each coupling structure being positioned on said base plate for engagement with an associated one of said coupling portions to detachably couple said base plate to said posts, each coupling portion being disengageable from its associated coupling structure by rotational deformation of said mounting member to uncouple said base plate from said posts.

5. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate to provide a backing for a sheet of sandpaper, means comprising a motor in said housing for imparting motion to the assembly of said base plate and said pad, first and second mounting members carried by said housing for supporting said assembly from said housing and formed from elastically deformable material to permit motion of said assembly relative to said housing by operation of said motor, each of said mounting members comprising a pair of posts, a spacer portion extending between and integrally joined to said posts at corresponding ends thereof, and a coupling portion integral with each post, said base plate being integrally formed with a coupling structure for each of said posts, each coupling structure being positioned to engage an associated one of said coupling portions to detachably couple said base plate to said posts, and each coupling portion being disengageable from its associated coupling structure by rotational deformation of its associated mounting member for uncoupling said base plate from said posts.

6. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate to provide a backing for a sheet of sandpaper, means comprising a motor supported by said housing for imparting motion to the assembly of said base plate and said pad, first and second mounting members carried by said housing for supporting said assembly from said housing and formed from elastically deformable material to permit motion of said assembly relative to said housing by operation of said motor, each of said mounting members comprising a pair of posts, a spacer portion extending between and integrally joined to said posts at corresponding ends thereof, and a coupling portion integral with each post at the end thereof opposite from its associated spacer portion, said base plate being integrally formed with a coupling structure for each of said posts, each coupling structure being positioned to engage an associated one of said coupling portions to detachably couple said base plate to said posts, and each coupling portion being disengageable from its associated coupling structure by torsional deflection of its associated post or by flexing its associated spacer portion to uncouple said base plate from said posts.

7. The hand-manipulatable, power-operated sanding machine defined in claim 6 wherein each coupling portion comprises a coupling flange that is rotatable from a coupling position to an uncoupling position that is angularly spaced from said coupling position by torsionally deflecting its associated post or by flexing its associated spacer portion, and wherein each coupling structure comprises a pair of shoulders positioned in a hole that is formed in said base plate for each coupling flange, said coupling flange being insertable into its associated hole beyond said shoulders when in said uncoupling position, and said coupling flange being engaged with the undersides of said shoulders when it is rotated within its associated hole to said coupling position.

8. The hand-manipulatable, power-operated sanding machine defined in claim 6 wherein said housing is longitudinally divided into a pair of separately formed shells, wherein means are provided for securing said shells together, wherein the spacer portion of each of said mounting members is trapped between said shells, and wherein said shells have wall portions that engage the spacer portion of each of Said mounting members to prevent flexure of said spacer portions in the assembled relation of said shells with said mounting members.

9. In a hand-manipulatable, power-operated sanding machine, a housing, a base plate, a pad secured to said base plate and providing a backing for a sheet of sandpaper, means comprising a motor in said housing for imparting motion to the assembly of said base plate and said pad, a plurality of torsionally deflectible posts of elastically deformable material supported at corresponding ends from said housing, each of said posts being integrally formed with a coupling portion, each coupling portion being rotatable from a coupling position to an uncoupling position that is angularly spaced from said coupling position by torsional deflection of its associated post, said base plate being integrally formed with a coupling structure for each of the coupling portions, each coupling portion being engaged with its associated coupling structure when in said coupling position to couple said posts to said base plate, and each coupling portion being disengaged from its associated coupling structure when in said uncoupling position to uncouple said posts from said base plate.

10. In a hand-manipulatable, power-operated sanding machine, a housing having a body portion, a pad assembly providing a backing for a sheet of sandpaper, a plurality of one-piece members of elastically deformable material suspending said pad assembly from said body portion to permit motion of said pad assembly relative to said housing, means comprising a motor in said housing for imparting motion to said pad assembly, at least said body portion of said housing being divided longitudinally into a pair of separately formed shells, and means securing said shells together, corresponding ends of said one-piece members being trapped between said shells and being held in place only by separable seating surface engagement with interior surfaces of said shells.

11. The hand-manipulatable, power-operated sanding machine defined in claim 10 wherein each of said one-piece members comprises a pair of spaced apart posts having their upper ends received in said body portion and a spacer portion integrally joined to the upper ends of said posts within said body portion, the lower ends of said posts being secured to a part of said pad assembly.

12. In a hand-manipulatable, power-operated sanding machine, a housing having a body portion, a pad assembly providing a backing for a sheet of sandpaper, first and second mounting members of elastically deformable material for suspending said pad assembly from said housing and permitting relative motion between said pad assembly and said housing, each of said mounting members comprising a pair of posts connected at corresponding ends to said pad assembly and a spacer portion integrally joined to and extending between said posts at the opposite ends thereof, at least said body portion of said housing being longitudinally divided into a pair of separately formed shells having a first pair of inwardly opening cavities and a second pair of inwardly opening cavities spaced from said first pair of cavities, and means securing said shells together, the spacer portion of said first member being received in the cavities of said first pair of cavities and being held in place only by separable seating surface engagement with interior cavity-defining surfaces of said shells, and said spacer portion of said second member being received in the cavities of said second pair of cavities and being held in place only by separable seating surface engagement with interior cavity-defining surfaces of said shells.

13. In a hand manipulatable, power operated sanding machine, a base plate of rectangular configuration, a pad secured to said base plate to provide a backing for a sheet of sandpaper, drive means for imparting motion to the assembly of said base plate and said pad, a pair of sandpaper holders, said base plate being integrally formed with at least one beaRing portion for each of said sandpaper holders, and each sandpaper holder being pivotally mounted directly on its associated bearing portion and having means integral with said bearing portions and said holders for preventing each holder from being disengaged from its associated bearing portions except when said holders are pivoted to pre-selected positions.

14. The hand-manipulatable, power-operated sanding machine of claim 13 having spring means for biasing said holders to their sandpaper-clamping positions, said spring means comprising a flat-sided leaf spring for each of said holder, each leaf spring being seated at one end thereof in a shallow recess in said base plate, and the other end of each leaf spring being seated against a portion of its associated holder.

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