US3355843A

US3355843A - Grinding and polishing pad

Info

Publication number: US3355843A
Application number: US404136A
Authority: US
Inventors: George E Bonin
Original assignee: Corning Glass Works
Current assignee: Corning Glass Works
Priority date: 1964-10-15
Filing date: 1964-10-15
Publication date: 1967-12-05
Anticipated expiration: 1984-12-05
Also published as: NL141807B; DE1502400A1; NL6513305A; DE1502400B2

Description

:"OOGDGQOQGGTSGQOO i Dec 5, 1967' G. E. BQNIN 3,355,843

GRINDING AND POLISHING PAD Filed Oct. l5, 1964 2 Sheets-$heet l /h `\/r\ T 09009000000009L90 0 0000000000000 0002000000`0H000 l 090000000900000 0000i000909000000 I l llllmw..

@000000000500000 I OOO. O0OOOOO @fl-n 0090090000 09000 I 000%0090000000000 000000000000000| 00000000i0090000d 000000000000090 l 000% 000000000000 00000000000000000 009000000090000 Q5: @000000000000000 g. 000000000990090l l: I

00000000900000-0 00000000000000 000000000900000 000000000000O &0 0090090000000090 INVENTOR. George E Bon/n ATTORNEY Dec. 5, 1967 G. E. BONIN 3,355,843

GRINDING AND POLISHING PAD Filed Oct. l5, 1964 2 Sheets-Sheet 2 A T TORNE Y United States Patent C 3,355,843 GRINDING AND PLISHING PAD George E. Bouin, Addison, NX., assigner to Corning Glass Works, Corning, NX., a corporation of New York Filed (let. 15, 1964, Ser. No. 404,135 Claims. (Ci. 51-397) ABSTRACT F THE DISCLSURE This invention relates `to an improved grinding and polishing pad, and more particularly to a flexible liner pad for finishing complex curvilinear surfaces without point loading.

`In the past, it has 'been customary to pumice and polish curvilinear glass-surfaces, such as TV panels and caps,` by utilizing'a pneumatically inflated flexible cylindrical sleeve. The pneumatic sleeve is .rotated about its longitudinal axis and is positioned tocontact a panel or cap rotated about a vertical axis. When pumicing, the outer surfacev of .the sleeve lis provided with rubber or the like, whereas when polishing, the sleeve is provided with a felt outer surface. Although the pneumatic sleeve deformed to approximate the contour of the convex rotating workpiece, and therefore provided some degree of polishing and pumicing,.it has not been completely satisfactory for various reasons. Gne disadvant-age resides in the fact that complete and continuons contact between the sleeve and the surface of the article cannot be maintained, resulting in intermittent or partial contact therebetween thus producing a rather low stock removal rate. A further disadvantage of the pneumatic type of removal is the fact that it necessitates extremely high power requirements for the amount of materials removed. Further, point loading is otbained by the slapping pne-umatic sleeve which produces zone removal and which not only induces breakage, but alsoV results in surface aberrations.

Other methods utilized in the past to grind and polish curvilinear surfaces .included the utilization of a hand pumice wheel. Not only is this method extremely timeconsuming and expensive, but also due to human error the Aresults are not necessarily accurate.

The present invention obviates the above-noted disadvantages by the utilization of an improved flexible liner pad construction which is contoured Iby a suitable pre-shaped support surface to complement the curvature of the workpiece to be finished. A plurality of such liner pads are secured at an offset end to the support surface and are provided on their back side with a plurality of fingers which maintain the polishing surface in spaced-apart relationship with the support surface. In addition, the plurality of ngers provide the polishing surface with uniform flexibility across its extent and accordingly eliminates point loading and zone finishing by facilitating sectional deflection in those areas subjected to increased load. In addition, the plurality of fingers permits the ready dispersion of excess slurry from the working surface.

It thus has been an object of my invention to provide an` improved grinding and polishing means for finishing the contoured surface of frangible material.

An additional object of my invention has been to provide an improved grinding and polishing liner pad for finishing curvilinear ware surfaces with improved removal rates without applying excessive local pressures upon any portion of the ware.

A further object of my invention has been to provide a iiexible liner pad which readily conforms to the contour of a support surface pre-shaped to complement the workpiece while maintaining the work surface in spaced-apart relation from the support surface so as to absorb sectional loading without deformation to the remainder of the liner.

These and other objects of my invention will become more apparent to those skilled in the art from the following disclosure and accompanying drawings in which,

FIGURE l is a `bottom plan view of an improved liner pad embodying my invention.

FIGURE 2 is a side elevational view shown in FIGURE l.

FIGURE 3 is an enlarged fragmental side elevational view of a liner pad embodying my invention illustrating local deformation obtained upon sectional loading which does not deform the remainder of the liner, thus providing an overall uniform surface arca contact irrespective of irregularities in the workpiece surface.

FIGURE 4 is a somewhat schematic elevational view illustrating the positionment of a plurality of liner pads shown in FIGURE l upon a suitably contoured support surface for complementarily finishing a television cap or the like.

Referring now to the drawings and particular-ly FIG- URES l and 2, a liner pad embodying my invention is shown at 10 having a main body portion 11 and an olfset connecting or `attachment portion 12. The main body portion has an upper working surface 13 which is adapted to complementarily engage the contoured surface of a workpiece to be finished. The under surface 14 of the body portion 11 is provided with a plurality of flexible tapered fingers 15 which extend outwardly therefrom a distance equal to the offset of the connecting portion 12. As noted particularly in FIGURE 2, several rows of lingers, extending along the edge opposite the offset attachment portion 12, are shown as shortened fingers 16, for reasons which will become more apparent hereafter.

The offset attachment portion 12 is formed integrally with the body portion 11 and has a reinforcing or attaching bar 17 embedded therein. The pad 1@ may be of any suitable material providing a good working surface, although I prefer to utilize rubber or neoprene. In order to maintain the attachment bar 17 in position within the connecting portion 12, a plurality of anchor holes 13 are provided through the bar so as to permit the rubber or neoprene to liow therethrough during the manufacture. Further, a plurality of mounting or attachment holes 19 extend through the connecting portion 12 to secure the liner pad 10 to a support surface. A suitable enforcing fabric 3i), such as duck fabric, may be embedded within the liner material to provide added durability and reinforcement for tensile strength.

Since the liner pad has been designed primarily for finishing curvilinear surfaces, both the hardness and flexibility of the working surface must be within defined limits to give maximum removal rates without imparting undesirable scratch patterns. These limits are controlled and maintained by utilizing rubber or neoprene type materials having a shore A durometer hardness of between about 50 to 90, and by spacing the plurality of exible fingers on about one-half inch to three-quarter inch centers. By utilizing such combination of parameters it is possible to provide a working surface which may be preshaped by a desired support surface to conform to the general contour. of the workpiece, while being liexible of the liner pad Lo conform to irregularities in the surface of such worknece.

The hardness of the rubber of neoprene utilized in the nody of the liner pad 1f), of course, cooperates with the iexibility derived from the plurality of fingers to proiuce the desired surface hardness presented to the workniece. I have found that a working range exists between about 50 and 90 shore A durometer and that optimum esults for television panels are obtained with a hardness nf about 70. This optimum hardness provides maximum glass removal rate while leaving a surface which is easily polishable. When the hardness reaches the upper limit of :he working range, scratch patterns are developed in the surface of the workpiece which are too deep to be effectively polished out; whereas when the hardness is below the lower limit, glass removal `rate is so low as to be virtually economically unfeasible. When used as a polishlng pad, the liner is provided with a felt working surface 13 which may be secured to the body portion 11 by my suitable means such as vulcanizing.

I have found that the center-to-center dimensions beween the fingers is an important factor in creating the desired flexibility. An optimum working range exists between about one-half inch and three-quarter inch spacing when utilizing fingers having a diameter of approximately one-quarter inch. When the spacing is greater than about one inch, soft spots develop on the working surface of the liner pad, which do not effectively cooperate with the surface of the workpiece. When the spacing is less than about one-half inch, the working surface be- :omes too rigid and defeats the tiexibility requirement. Each finger is a pressure point which cooperates with the adjacent fingers to provide a synergistic effect for optimum surface support.

Referring now to FIGURE 3, the sectional loading of a liner pad 10, such as might be occasioned by irregularities in the surface of the workpece, is schematically illustrated. It can be seen where a sectional or regional load L is applied to the surface 13 of the pad 10, the fingers 15 beneath that section defiect to permit the sectional surface to conform to the irregularity while the remainder of the liner pad retains its original configuration, which, as previously mentioned, conforms to the general configuration of the remainder of the workpiece. This built-in provision for sectional deflection not only inhibits point loading of the workpiece but also zone grinding.

FIGURE 4 is a fragmental view schematically illustrating a mounting of a plurality of liner pads shown in FIGURES 1 and 2. The liner pads 10 are secured to a suitable support member 2t) which may be supported by any suitable means such as bearings 21 for rotation. The member is provided with a pre-shaped support surface 22 for contouring the working surface 13 of the pad 10 to substantially conform to the curvilinear contour of a workpiece W. The workpiece may be mounted upon a suitable holder 23 and rotated about a shaft 24.

As shown in FIGURE 4, the offset connecting portions 12 of the pads 10 are secured to the support surface by screw means projecting through attaching bars 17. If desired, end portions 17a of the attachment bar which extend outwardly of the pad, may be provided with a suitable clamping device to secure the pad to the support surface. In order to form a continuous upper working surface the end opposite the connecting portion 12 is provided with shortened lingers 16, which overlie and rest upon the adjacent offset connecting portion 12 to maintain the working surface 13 of the pads in a continuous free-flowing orientation. In addition, these shortened fingers 16 overlying the single end correcting portion cooperate with the passage formed between abutting pads to provide a passageway for the removal of slurry from the work surface, so that the excess slurry may fiow downwardly between the adjacent liner pads and between the shortened fingers 16 and along the fingers i5 to a suitable draw-off area in the support member.

Although I have disclosed the now preferred embodiments of my invention it will be apparent to those skilled in the art that various changes and modifications may be made thereto without departing from the spirit and scope thereof as defined in the appended claims.

I claim:

1. An improved liner pad construction for finishing contoured surfaces of a curvilinear workpiece which comprises, a body portion of fiexible material, an offset connecting portion along one end of said body portion, an upper working surface formed on said body portion, a plurality of spaced-apart flexible fingers extending outwardly from a lower surface of said body portion a distance equal to the offset of said connecting portion, said fingers being formed integrally with said body portion and fiexibly maintaining said working surface in spacedapart relationship from a support surface so as to permit said working surface to conform to the configuration of the workpiece, an attachment bar embedded within said attachment portion to facilitate the securement of said body portion to a support surface, and said body portion together with its integrally formed fingers having a shore A durometer hardness of between about 50 and 90.

2. A liner pad as defined in claim 1 wherein said plurality of fingers are equally spaced-apart on centers within the range of between -1/2 inch and 1%, inch to impart uniform flexibility to the working surface and permit regional deflection of the working surface in response to irregularities in the surface of the workpiece while maintaining conformity with the remainder of the workpiece surface.

3. An improved liner pad construction for finishing contoured surfaces of a curvilinear workpiece which comprises, a body portion of fiexible material, an offset connecting portion along one end of said body portion, an upper working surface formed on said body portion, a plurality of flexible fingers extending outwardly from a lower surface of said body portion a distance equal to the offset of said connecting portion, said fingers being formed integrally with said body portion and fiexibly maintaining said working surface in spaced-apart relationship from a support surface so as to permit said working surface to conform to the configuration of the workpiece, an attachment bar embedded within said attachment portion to facilitate the securement of said body portion to a support surface, and a plurality of fingers along an edge opposite said connecting portion having a shortened length so as to overlie the connecting portion of an adjacent liner pad and form a discharge passageway for excess slurry therebetween.

4. In combination with finishing apparatus having a contoured support surface, improved liner pad means for finishing curvilinear surfaces of a frangible workpiece which comprises, a body portion of flexible material, an upper working surface conformable to the contour of the workpiece, and means formed integrally with said body portion cooperating with the contour of said support surface to conform the Work surface to the general contour of the workpiece while permitting sectional deflection of the work surface to compensate for irregularities in the surface of the workpiece; said last-mentioned means comprising a plurality of spaced-apart flexible fingers formed integrally with said body portion and extending outwardly from an under surface thereof; and reinforced offset means for connecting said body portion to said support surface.

5. In combination with finishing apparatus having a contoured support surface, an improved flexible pad construction for finishing curvilinear surfaces of a frangible workpiece which comprises, a body portion of fiexible material, an upper working surface formed on said body portion, and means for fiexibly maintaining said working surface in spaced-apart relation from said support surface while permitting said working surface to comple- 2,058,257 10/ 1936 Porteous 241-182 X mentarily contour the surface to the workpiece; said exi- 2,178,728 11/ 1939 Schneible 51-8 ble means comprising a plurality of spaced-apart resilient 3,236,010 2/ 1966 Evans 51--283 fingers extending outwardly from a lower surface of said 34,001 12/1961 Mayall 15- 215 body portion and terminating at their outer ends in a 5 2,672,637 3/1954 Allen 15 513 common plane; and an offset attachment portion formed 3 100 312 8/1963 Williams 15 215 on one end of said body portion and lying substantially n within the plane of the outer end of said resilient iingers FOREIGN PATENTS for attaching the pad to said support surface. 625,105 6/1949 Great Britain References Cited lo UNITED STATES P C. Primary Examiner.

730,900 6/ 1903 Fuller 241-182 D. G. KELLY, Assistant Examiner.

2,024,439 12/1935 Evans.

Claims

1. AN IMPROVED LINER PAD CONSTRUCTION FOR FINISHING CONTOURED SURFACES OF A CURVILINEAR WORKPIECE WHICH COMPRISES, A BODY PORTION OF FLEXIBLE MATERIAL, AN OFFSET CONNECTING PORTION ALONG ONE END OF SAID BODY PORTION, AN UPPER WORKING SURFACE FORMED ON SAID BODY PORTION, A PLURALITY OF SPACED-APART FLEXIBLE FINGERS EXTENDING OUTWARDLY FROM A LOWER SURFACE OF SAID BODY PORTION A DISTANCE EQUAL TO THE OFFSET OF SAID CONNECTING PORTION, SAID FINGERS BEING FORMED INTEGRALLY WITH SAID BODY PORTION AND FLEXIBLY MAINTAINING SAID WORKING SURFACE IN SPACEDAPART RELATIONSHIP FROM A SUPPORT SURFACE SO AS TO PERMIT SAID WORKING SURFACE TO CONFORM TO THE CONFIGURATION OF THE WORKPIECE, AN ATTACHMENT BAR EMBEDDED WITHIN SAID ATTACHMENT PORTION TO FACILITATE THE SECUREMENT OF SAID BODY PORTION TO A SUPPORT SURFACE, AND SAID BODY PORTION TOGETHER WITH ITS INTEGRALLY FORMED FINGERS HAVING A SHORE A DUROMETER HARDNESS OF BETWEEN ABOUT 50 AND 90.