US3520090A - Surface finishing machine - Google Patents

Description

July 14, 1970 D. LEE 3,520,090

SURFACE FINISHING MACHINE Filed Jan. 29, 1968 2 Sheets-Sheet l h 23 3 i F W 43 7 Fig.2

//Vl N7'OR Dona/d L66 .HSLOUGH AT ORNEY July 14, 1970 D. LEE 3,520,090

SURFACE FINISHING MACHINE Filed Jan. 29, 1968 2 Sheets-Sheet 2 *5O f8 3/50 //VVNTOR Q57 Doncz/ Lee 52 F|$7 BY 4 1/. H. a: OUGH ATTORNEY United States Patent 0,

3,520,090 SURFACE FINISHING MACHINE Donald Lee, 3633 Straudhill Road, Shaker Heights, Ohio 44122 Filed Jan. 29, 1968, Ser. No. 701,144 Int. Cl. B24b 23/00; B24d 17/00 U.S. Cl. 51-170 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to surface treating apparatus of the type having a rotatable member adapted to be moved across the surface to be treated and relates more particularly to a surface finishing machine for grinding smoothing, polishing and finishing operations.

The invention as herein disclosed comprises a hand grinder or polisher having a motor driven shaft which carries an eccentrically mounted pivot member. A freely rotatable mounting plate is mounted on the pivot member and a counterweight is also carried by the drive shaft for offsetting the centrifugal force. caused by the eccentric throw of the mounting plate. The mounting plate carries a resilient disk and a centrally disposed socket member adapted to receive a disk-shaped plug. The plug is adapted to snap into the socket and has a finishing disk attached thereto whereby said disk can be quickly and easily attached to or removed from the machine. As disclosed herein by way of illustration, the finishing disk is of the sanding or abrasive type but it will be understood that nonabrading disks may be used. It is anticipated that a supply of finishing disks may be provided, each having a plug attached thereto, and it is further anticipiated that a plurality of disks may be mounted on a single plug to be successively used, as will hereinlater become apparent.

Where. reference is made in the following specification and claims to a surface finishing machine or finishing machine it will be understood that the same is intended to cover machine adapted for grinding, abrading, smoothing, polishing and similarly treating the surface of metal, wood, plastic or the like. Use of the term finishing or finishing disk refers to materials for use in effecting the above-referred to grinding, abrading, smoothing, polishing and similar operations.

In general, the object of this invention is to provide a surface finishing machine which has improved balance in operation, easier handling characteristics, simple means for quickly and easily removing and replacing the finishing material, and is simple, sturdy, and durable in construction.

More specifically, it is an object of this invention to provide a surface finishing machine of the type set forth above wherein the freely rotatable mounting plate is cupshaped having an upturned peripheral flange and wherein the counterweight is disposed entirely within the cup shaped mounting plate to lower the center of gravity of the machine.

Another object of the invention is to provide a surface finishing machine of the type referred to having improved means for quickly and easily attaching or removing a finishing disk to the mounting plate thereof.

Still another object of the invention is to provide a surface finishing machine as set forth above having a downwardly open socket in the center of the rotating 3,520,090 Patented July 14, 1970 ice member and a plug adapted to snap fit into said socket, the plug having a finishing disk secured thereto.

Another object of the invention is to provide the aforesaid plug and socket construction wherein the plug constitutes a throwaway item to be supplied with new finishing disks.

Yet another object of the invention is to provide a plug as set forth above having a finishing disk adhesively secured thereto at tile center of said disk.

A further object of the invention is to provide a plug having a finishing disk attached thereto and additional finishing disks overlapping and detachably secured to the first mentioned disk.

A still further object is to provide finishing disk attachment means as set forth above wherein each disk is provided with a strip of pressure sensitive adhesive on its upper surface adjacent to the outer edge thereof and a corresponding plain surface portion on its lower surface whereby a number of finishing disks can be secured together and carried by a single plug to be peeled off as they are worn out.

Other objects of the invention and the invention itself will be apparent from the following detailed description of the invention and the accompanying drawings, in which said drawings:

FIG. 1 is a top plan view of the surface finishing machine of this invention;

FIG. 2 is a section taken along the 1ine.2-2 of FIG. 1;

FIG. 3 is a section taken along the line 3-3 of FIG. 2;

FIG. 4 is an enlarged perspective view of a socket member;

FIG. 5 is an enlarged perspective view of a plug adapted to snap fit into said socket member;

FIG. 6 is an exploded enlarged detail view in cross section of the socket, plug, and associated parts; and

FIG. 7 is an exploded section through peripheral edge portions of modified forms of the finishing disk.

Referring now to the drawings in all of which like parts are designated by like reference numerals and particularly to FIGS. '1, 2 and 6, the. surface finishing machine of this invention is generally indicated at 10 and comprises a housing 11 having a motor 12 mounted therein. The motor 12 is a conventional electric motor and is mounted upon a vertical axis whereby the drive shaft 13 thereof projects downwardly. The lower end of the drive shaft 13 is threaded as indicated at 14 whereby it is adapted to be thread fitted into a boss 15 of a counterweight 16. The boss 15 of said counterweight also carries an eccentric pivot pin 17 which is thread fitted upwardly into the :boss and carries a freely rotatable, cup shaped mounting plate 18. Said mounting plate includes a resilient, disk shaped backup member 19 secured to the lower surface of the mounting plate 18 in any suitable manner; and a surface. finishing disk 20 is detachably secured to the lower surface of the backup member 19 by a socket and plug assembly generally indicated at 21.

From the foregoing, it will be readily apparent that the mounting plate 18, backup member 19, and finishing disk 20 all move together in an eccentric path around the drive shaft 13 with the recited member being freely rotatable during such eccentric movement about a common axis.

As herein shown, the housing 11 is preferably a casting made of a suitable metal, plastic or other suitable material, having an upwardly tapered body portion 22 and a radially outwardly disposed skirt 23 at its lower end. A first gripping handle 24 projects laterally and upwardly from the skirt 23 by means of arms 25. A second gripping handle 26 is cast into the upper end wall 27 of the body portion 22. An operator of the machine of this invention grasps the first gripping handle 24 in one hand while engaging the second gripping handle 26 with the other hand for full control and manipulation of the machine over the surface being treated.

The motor 12 is mounted within the body portion 22 in a conventional manner by means of a plurality of elongated bolts 28 which project downwardly through inner bosses 29 and through peripheral edge portions of said motor.

As shown in FIG. 3, the counterweight 16 has a semicircular, symmetrical weight portion 30 which projects toward the left in FIG. 2 or in a direction with respect to the drive shaft 13 which is opposite to the eccentric pivot pin 17. The mounting plate 18 has an upstanding peripheral flange 31 surmounted at its upper edge by a circumferentially continuous, radially outwardly projecting flange 32. The flanges 31 and 32 are disposed entirely Within the peripheral skirt 23 whereby only a bottom wall 33 of said mounting plate projects slightly below said skirt.

FIG. 3 illustrates the manner in which the weight portion 30 of the counterweight 16 is always disposed diametrically opposite the eccentric throw of the mounting plate 18 whereby the centrifugal force of the eccentric movement of said mounting plate is effectively counterbalanced at all times by said weight portion. It will be further noted that said weight portion 30 is disposed entirely within the cup shaped mounting plate 18 whereby the center of gravity of the entire machine is kept substantially low.

The bottom wall 33 of the mounting plate 18 has a centrally disposed, upwardly projecting boss 34 which is centrally recessed at 35 to receive a ballbearing member 36 (FIGS. 2, 6). Said ballbearing member is retained within the recess 35 by means of a plurality of circumferentially spaced screws 37 disposed around the outer edge portion of the boss 34 with their heads overlapping an outer race portion 36a of said ballbearing member.

In the bottom of the recess 35, the bottom Wall 33 has a through aperture 38 which is adapted to receive a downwardly open cylindrical socket 39. Said socket has an upper end wall 40 which is disposed below the ball bearing member 36 and an inner circumferential wall surface 41 which converges slightly in an upward direction. The lower end of said pivot pin is provided with an enlarged head 42 which overlaps an inner race portion 36b of the ballbearing member 36 whereby the mounting plate 18 is rotatably mounted upon said pivot pin.

As shown in FIGS. 2 and 6, the resilient backup member 19 has a frustoconical, concave recess 43 centrally of its bottom surface, the lower edges of the socket 39 terminating at the bottom of said recess 43. A slightly upwardly tapering plug 44, detailed in FIGS. 5 and 6, is adapted to snap upwardly into the downwardly open socket 39. Said plug 44 is disk shaped and is provided with a radially outwardly projecting, circumferentially continuous flange 45 at its lower end which is slightly larger in diameter and radially outwardly overlaps the lower edge of the socket 39. A finishing disk 20 is glued, bonded, or otherwise suitably secured to the bottom surface of the plug 44 whereby when said plug is snap fitted into the socket 39, said finishing disk is carried against the bottom surface of the flexible member 19 and rotates therewith. Thus, no part of the plug 44 is exposed to contact the work surface in use of the surface finishing machine 10. The socket 39 and plug 44 may be made of any suitable material, and as herein illustrated the parts are made of plastic.

The plug 44 is designed to be a small, inexpensive member, one of which may be provided for each finishing disk 20 to be thrown away when the disk is worn out. It is anticipated that said finishing disks would be supplied each mounted upon a plug whereby a user of the finishing machine of this invention need only snap off the old, worn-out finishing disk and snap a new one into place. By exerting only moderate pressure upon the plug, said plug will seat firmly within the socket bringing the flange 45 against the lower peripheral edge of the socket 39 ,The modification of FIG. 7 shows the manner in which a plurality of finishing disks can be mounted upon a single plug 44 to be successively used and, when worn out, peeled away from the remaining disks. The modified finishing disks are indicated at 50, each disk having surface finishing means such as an abrasive material 51 on the lower side thereof. An annular plain surface portion 52-is provided at the outer periphery of each disk around the, abrasive material 51, and an annular strip 53 of pressure sensitive adhesive is disposed on the upper surface of each disk immediately above said annular plain surface portion. It will be readily seen that a plurality of finishing disks 50 may be removably attached to each other by pressing the strips 53 of pressure sensitive adhesive against the annular plain surface portions 52, it being understood that the uppermost disk would be secured to a plug 44 as described above. As each successive disk is worn out, it can be readily peeled from the bottom of the stack.

From the foregoing it will be seen that the present invention affords a finishing machine which is easily and comfortably held and manipulated, has a low center of gravity for low, relatively vibration free operation, and provides means for quickly and easily renewing the abrasive surface thereof.

It will be understood that many changes in the details of the invention as herein described and illustrated may be made without, however, departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

1. In a surface finishing machine, a motor having a downwardly projecting, vertical drive shaft; a horizontal cup shaped mounting plate having an upturned peripheral flange; said mounting plate freely rotatably mounted upon eccentric pivot means disposed laterally of and parallel with said drive shaft; means connecting said drive shaft and said pivot means whereby said pivot means and mounting plate are rotated in an eccentric path with respect to said drive shaft; counterweight means rigidly mounted with respect to said drive shaft and projecting from the side of said drive shaft opposite to said eccentric pivot means; said counterweight means being disposed entirely within said cup shaped mounting plate in a horizontal plane coplanar with said means connecting said drive shaft and said pivot means; said mounting plate including resilient backup means for a disk of surface finishing material; and means for detachably mounting surface finishing material to the bottom surface of said backup means.

2. In a surface finishing machine as set forth in claim 1: said means for detachably mounting said finishing material comprising a downwardly open socket member carried by said mounting plate; a plug member; a finishing disk carried by said plug member; said plug member having a portion thereof adapted to snap fit into said socket.

3. In a surface finishing machine as set forth in claim 1: said means for detachably mounting said finishing material comprising a downwardly open substantially cylindrical socket member carried by said mounting plate and opening at the center of said backup member; a plug member having a finishing disk attached thereto; said plug member having a substantially cylindrical portion adapted to snap fit into said socket to attach said finishing disk to the bottom surface of said backup member.

4. In a surface finishing machine as set forth in claim 1: said means for detachbly mounting said finishing material comprising a downwardly open substantially cylindrical socket member carried by said mounting plate and opening at the center of said backup member; a disk shaped plug member having a radially projecting flange at the lower end thereof; a finishing disk secured coaxial- 5 1y to the bottom surface of said disk shaped plug; said plug having a substantially cylindrical portion adapted to snap fit into said socket member whereby said flange is seated against the lower edge of said socket member and said finishing disk is detachably secured to said resilient backup means.

5. In a surface finishing machine as set forth in claim 4: said substantially cylindrical portion of said plug and the inner wall surface of said socket member being tapered slightly in an upward direction.

6. In a surface finishing machine as set forth in claim 4: said finishing disk being glued to the bottom surface of said plug.

7. In a surface finishing machine as set forth in claim 1: said means for detachably mounting said finishing material comprising a downwardly open socket member carried by said mounting plate; a plug member; a plurality of coaxial finishing disks carried by said plug member; a first of said disks being secured coaxially to the bottom surface of said plug; at least the other of said disks having annular strips of pressure sensitive adhesive on the top surfaces thereof adjacent to the outer peripheral edges thereof; all of said disks having annular plain surface portions on the bottom surfaces thereof aligned with said strips and all of said disks being pressed together whereby said disks can be sequentially used and successively peeled from the stack of disks and discarded as each disk is worn out.

References Cited UNITED STATES PATENTS 2,626,489 1/1953 Thompson 51-39l X 2,991,596 7/1961 Walters 51376 1,587,843 6/1926 Koreneff 51170.2 X

FOREIGN PATENTS 496,898 8/1954 Italy.

JAMES L. JONES, JR., Primary Examiner US. Cl. X.R.

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