CA2064452A1 - Contact wheel and method - Google Patents

Abstract

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ABSTRACT
The contact wheel according to the present invention is adapted to support an endless coated abrasive belt during abrading of a workpiece. The contact wheel comprises a hub having an axis and a generally cylindrical peripheral surface about the axis, a generally monolithic contact portion having cylindrical inner surface coaxial with the hub and which is mounted on the peripheral surface of the hub, and an outer cylindrical coaxial peripheral face surface having axial spaced edges. The contact portion has circumferentially spaced parallel elongate grooves having opposite ends. The grooves are recessed from the face surface with land parts of the peripheral face disposed between the grooves. The contact portion has at least one end of each of the grooves spaced from the adjacent edge of the face surface to provide a continuous support part of the peripheral face surface adjacent the adjacent edge of the face surface. The invention also includes a method of grinding a workpiece at a first relatively high cut rate and then at a second relatively lower cut rate.

Description

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C~NTACT ~;Y3EIEEL AND METE~OD

Technical Field The present invention relates generally to back-up supports ~or use in grinding assemblies that include coated abrasive belts for producing a new surface on a workpiece, and more particularly to contact wheels for supporting coated abrasive belts.

Backqround Art Known grinding assemblies which include coated abrasive belts entrained over contact wheel~ are adapted to produce new sur~aces on workpieces, such as forgings 15 or castings. One such grinding assembly is known as a backstand grinding assembly and comprises a contact wheel and at least one idler wheel, a means for driving or rotating the contact wheel, an endless coated abrasive belt entrained over the idler and contact wheels, a means 20 for tensioning the belt to the appropriate tension and tracking means for ensuring that the abrasive belt tracks properly on the contact wheel. The endless coated abrasive belt includes a backing with front and rear surfaces and an abrasive agglomerate or granules attached 25 along the front surface by a bond system. The contact or idler wheel is rotated and drives the endless abrasive belt. To grind the workpiece, the workpiece is brought into contact (e.g. manually or automatically) with the coated abrasive belt which is supported by the contact 30 wheel. The surface or area of contact between the workpiece and the abrasive belt is referred to in this application as the abrading interface.
Contact wheels may be constructed from materials such as cloth, rubber, metal and combinations 35 thereof. Cloth and rubber contact wheels are described on pages 111-128 of Chapter 5 of Coated Abrasives -Modern Tool of Industry, Coated Abrasives Manufacturers 7 Institute, McGraw-Hill Book Company, Inc., first edition, (1958). Rubber contact wheels may be constructed ~rom rubber "tires" ranging in Shore A durometer hardness from 20 to 100 which may be vulcanized or molded to aluminum 5 wheels or t~ metal rims mounted on hubs.
Generally, the harder the contact wheel, the faster the coated abrasive belt removes the stock ~rom the workpiece (i.e. the higher the "cut rate"). However, the harder the material used to construct the contact 10 wheel (or the higher the cut rate), the coarser the resultant surface finish on the workpiece. In some abrading operations, the hardness of the contact wheel is typically limited by the requirement that the contact wheel should conform to the workpiece to be abraded, and 15 a user will generally choose the hardest contact wheel that will sufficiently conform to the workpiece to be abraded.
A first known contact wheel is known as a plain-faced contact wheel. As used in this application 20 "Face" applies to the peripheral surface of the contact wheel. Plain-faced contact wheels have a generally cylindrical continuous outer periphery and are utilized for example, for very fine polishing or burnishing. Such plain-faced contact wheels assure the maximum belt area 25 in contact with the workpiece and thus the lowest unit grain pressure at the abrading interface.
A second known contact wh~el is known as a serrated contact wheel and is generally used for operations which require an increased stock or material 30 removal rate (i.e. a higher cut rate) r and reduced heat at the abrading interface. Generally as cut rate increases, the surface finish on the workpiece becomes coarser. Thus, serrated contact wheels are particularly suitable ~or grinding operations which require a large 35 amount of stock remo~al and which may tolerate a relatively coarse or rougher surface finish, at least until the workpiece is subsequently polished. One _ 3 2~ 2 example of such an application is when a casting gate or flash is ground from a cast part such as a golf club.
Serrations on the periphery of a serrated contact wheel produce alternate lands and grooves across 5 the entire ~ace of a wheel. The ratio of groove width to land width, the depth of the groove, the shape o~ the land, and the hardness of the wheel a~ect the cutting action (e.g. the cut rate) and performance of the coated abrasive belt. The existence of the grooves in the 10 serrated contact wheel reduces the workpiece temperature during the grinding operation, and also increases the effective pressure at the abrading interface. The increase in the effective pressure between the abrasive belt and the workpiece affords a higher cut rate but may 15 lead to side effects such as increased abrasive belt wear and noise levels. One example of increased abrasive helt wear is known as ~Ishelling~ wherein the abrasive grains or agglomerates are prematurely released from the bond systems of the coated abrasive belts. In ~O some grinding operations, shelling is particularly a problem at the edge of a serrated contact wheel.
Increasing the groove width of a serrated contact wheel at the expense of land area increases the effective pressure until a point is reached where the 25 rigidity of the land and performance of the contact wheel is adversely affected. Typically, the narrower the land width, the more likely the land will deflect or flex during an abrading operation. Such-flexing may result in fatigue damage especially at the root or the bottom 30 portion of the land. If the groove width is too large, shelling and destruction of the belt along with damage to the contact wheel may result due to the increased unit pressures. If thP groove width is too narrow, cut rate may be sacrificed. The depth and shape of the land along 35 with the durometer (wheel hardness) govern the point where further increase in groove width tends to decrease ~ 4 --effective unit pressure by introducing resiliency and a heightened potential fGr flexing.
Existing contact wheels and the effects of factors such as wheel diameter, hardness, eontact area, 5 impact, and serrations on the resultant ground workpiece are described in "Guidelinles for Grinding", the Industrial Abrasives Division of Minneso~a Mining and Man~lfacturing Company (3M) #60-4400-0385-7 ~65.4) VP.
Known rubber contact wheels having serrations 10 extending entirely across their peripheral face have a tendency to fail or breakdown over time, partlcularly along their edges. It is believed that such failure may be attributed to several phenomenon. First, since the edges of the serrated contact wheel are not supported as 15 well as the middle portion of the contact wheel, the portions of the lands adjacent the edgss of the contact wheel are more susceptible to amplified and repeated flexing which eventually results in fatigue damage and other types of failure particularly at the root or base 20 of the land adjacent the edge of the contact wheel.
Second, the amplified flexing of the portions of the lands adjacent the edges of the contact wheel affords increased penetration of the belt and workpiece into the grooves resulting in impact between the land and the 25 belt/workpiece. Such impact potentially damages the contact wheel, belt and workpiece. Additionally, in some grinding operations the abrasive belts tend to drift from the edge of a contact wheel and expose the edge of the ~heel to direct contact with the workpiece which may 30 result in damage both to the contact wheel and the workpiece.
Existing contact wheels also encounter problems due to their limited usefulness. For example, if a grinding procedure first requires a high cut rate 35 followed by a second polishing operation, a user may generally (1) use a serrated faced contact wheel with an abrasive belt and then (2) use a plain-faced contact 2~6~?.

wheel with the same or finer grade abrasive belt. A
serrated and plain-faced contact wheel may be ganged together for such a procedure. If the two wheels are not care~ully aligned, a seam is present at the inter~ace 5 between the wheels which may leave a mark on a workpiece.
If the plain-~aced or serrated contact wheels are located at locations remote from each other, changing between the two contact wheels wastes time. Additionally, as mentioned above, shelling of the abrasive grains and 10 destruction of the edges of the wheel may be problems, particularly when a serrated contact wheel is used.

Disclosure of the Invention The present invention provides a contact wheel 15 for use in a grinding assembly for forming a new surface on an object such as a forging (e.g. a golf club or a wrench) or a casting (e.g. a golf club or a faucet). The present invention provides a contact wheel with both serrated and plain-faced or "support" portions which 20 resists damage to its edges, which increases the cut rate over conventional serrated contact wheels by providing increased support for the lands of the serrated portions to deter undesirable flexing of the lands, which reduces the potential for damage and premature wear including 25 shelling of an abrasive belt, which reduces the effective pressure at the abrading interface when the abrading interface is adjacent the edge of the wheel, and which affords a single contact wheel so that an operator may conveniently and efficiently use the serrated portion of 30 the wheel for stock removal and the support portion of the wheel for finishing.
The contact wheel according to the present invention is adapted to support an endless coated abrasive belt during abrading or grinding of a workpiece.
35 The contact wheel comprises a hub having an axis and a generally cylindrical peripheral surface about the axis, a generally monolithic contact portion having a ~ 6 cylindrical inner surface coaxial with the hub and which is mounted on the peripheral surface of the hub, and ~n outer cylindrical coaxial peripheral face surface having axial spaced edges. The contact portion has 5 circumferentially spaced parallel elongate grooves having opposite ends. The grooves are recessed from the face surface with land parts of the peripheral face disposed between the grooves. The contact portion has at least one end of each of the qrooves spaced from the adjacent 10 edge of the face surface to provide a continuous support part of the peripheral face surface adjacent the adjacent edge of the face surface.
According to one embodimsnt of the present invention, only one end of each of the grooves is spaced 15 from the adjacent edge of the face surface. According to another embodiment of the present invention both ends of each of the grooves are spaced from the adjacent edges of the face surface to provide continuous support parts of the peripheral face surface adjacent both edges of the 20 face surface.
The contact wheel of the present invention may also be conveniently and efficiently utilized in a novel method for grinding or abrading a workpiece wherein the same contact wheel is used in grinding operations which 25 require a first relatively high cut rate for stocX
removal and a second relatively lower cut rate for finishing. The method of abrading a workpiece using a single contact wheel comprises the steps of (l) providing a hub having an axis and a generally cylindrical 30 peripheral surface about the axis, (2) providing a gener~lly monolithic contact portion having a cylindrical inner surface coaxial with the hub, and an outer cylindrical coaxial peripheral face surface having axial spaced edges, ~3) mounting the cylindrical inner surface 35 of the contact portion on the peripheral surface of the hub, (4) providing the contact portion with circumferentially spaced parallel elongate grooves having 2 ~ 2 opposite ends, the grooves being recessed from the face surface with land parts of the peripheral face disposed betwesn the grooves, (5~ spacing at least one end of each of the grooves from the ad~acent edge of the face surface 5 to provide a continuous support part of the peripheral face surface adjacent the adjacent edge; (6) providing an endless coated abrasive bel1; adapted to grind the workpiece, (7) supporting the endless coated abrasive belt with the contact portion, ~8) grinding the workpiece lO at a relatively high cut rate at a position generally adjacent the land parts; and (9) grinding the workpiece at a different and relatively lower cut rate at a position generally adjacent the continuous support part.

Brief Descri~tion of the Drawing The present invention will be further described with reference to the accompanying drawing wherein like reference numerals refer to like parts in the several 20 views, and wherein:
Figure 1 is a perspective view of a first embodiment of contact wheel according to the present invention illustrating continuous support parts adjacent both edges of the outer peripheral face of the wheel;
Figure 2 is a sectional view of the contact wheel shown in Figure 1 taken approximately along line 2-2 of Figure l with portions broken away to show detail;
Figure 3 is a front vertical view of a second embodiment of contact wheel according to the present 30 invention;
Figure 4 is a schematic illustration of a grinding assembly which includes the contact wheel of the present invention and a workpiece to be abraded; and Figure 5 is a front vertical view of a third 35 embodiment of contact wheel according to the present invention.

Detailed Description Referring now to Figures 1, 2 and 4 of the drawing, there is shown a first embodimPnt of contact wheel 10 according to the present invention which is 5 adapted for use with a grinding assembly which includes a coated abrasive belt for creating a new surface on a workpiece 4 that may be initially relatively rough, such as a golf club or wrench formecl by means such as but not limited to forging mechanisms or investment castings.
Figure 4 schematically illustrates a backstand grinding assembly 40 which comprises the contact wheel 10 and an idler wheel 42. The grinding assembly 40 includes a continuous abrasive belt 17 (e.g., the abrasive belt sold by Minnesota Mining and Manufacturing, St. Paul 15 Minnesota, under th2 trade designation 3M '7Regal" T.M.
Resin Bond Cloth Belts, or the abrasive belts also sold by Minnesota Mining and Manufacturing Company, St. Paul, Minnesota, under the trade designation 3M 331D
"Three-M-ite" T.M. Resin Bond Cloth Belts or 3M 359F
~0 "Multicut" T.M. Resin Bond Cloth Belts) having a flexihle backing with front and rear surfaces 18 and 19, and abrasive grain or agglomerate attached along its front surface 18 by a bond system, means for driving or rotating the contact wheel 10 to thereby drive the 25 abrasive belt 17 in a first direction along a path relative to the workpiece 4 in the form of any convantional contact wheel drive mechanism 43, such as, but not limited to the mechanisms associated with backstands, polishing jacks or vertical slack belt 30 machines sold by KLK Industries, Crystal, Minnesota, or G ~ P Industries, Indianapolis, Indiana.
The idler 42 and contact 10 wheels are spaced and the abrasive belt 17 is entrained over them~ A means for tensioning the belt 17 to the appropriate tension is 35 provided in the form of any convsntional belt tensioning device 44 such as pneumatic or spring tensioning or dead weight mechanisms. A tracking means that ensuras the abrasive belt 17 tracks properly is provided in the form of any conventional belt tracking device 46, such as crowned idler wheels, center pivot tracking systems or pneumatic trackers. The contact wheel 10 is rotated by 5 the contact wheel drive mechanism 43 (alternatively the idler wheel 42 may be rotated) and drives the endless abrasive belt 17 which also rides over the idler wheel 42. During grinding, the contact wheel 10 supports the coated abrasive belt 17 at the abrading interface (Figure 10 4~.
While the belt grinding assembly 40 has been described with reference to a backstand grinding assembly it should be noted that the contact wheel 10 and the method according to the present invention may be 15 practiced with any suitable grinding assembly that utilizes contact wheels such as, but not limited to, grinding a~semblies with endless and non-endless abrasive belts, and grinding assemblies with a plurality of idler wheels. For example, the bench, formed wheel, 20 conveyorized, centerless, surface, flexible bed sheet, rotary table surface, and swing yrinders (described on pages 19-21 of Metalworking, Reference Manual, published by the Industrial Abrasives Division of ~Iinnesota Mining and Manufacturing, ~60-4400-036~-7 (1294)JR) may utilize 25 the contact wheel and method of the present invention.
Referring now to Figures 1 and 2 there is shown a first embodiment of contact wheel 10 according to the present invention. The contact wheel 10 comprises a hub 11 having an axis and a generally cylindrical peripheral 30 surface 12 about the axis. The hub 11 may be constructed of metal or a high strenqth plastic and includes surfaces defining an arbor hole 22 for mounting the wheel 10 on a suitable drive shaft for the drive mechanism ~3.
The contact wheel 10 also comprises a generally monolithic contact portion 24 having a cylindrical inner surface 25 coaxial with the hub 11 and mounted on the 2 ~

peripheral surface 12 of the hub 11 by any suitable methods such as vulcanization, mechanical fasteners, molding or chemical bonding, and an outer cylindrical coaxial peripheral face surface 27 having axial spaced 5 edges 32 and 34. The contact portion 24 ha~
circumferentially spaced parallel elongate grooves 53 having opposite ends 54 and 56. The grooves 53 are recessed from the face surface 27 with land parts of the peripheral face surface 27 dispo~ed between the grooves 10 53. The grooves may be disposed at an angle relative to the axis of the hub between 5 and 85 degrees and are preferably disposed at an angle between 30 and 50 degrees. The contact portion 24 has at least one end 54 or 56 of each of the grooves 53 spaced from the 15 adjacent edge 32 and 34 of the face surface 27 to provide a continuous support or "smooth" part 36 of the peripheral face surface 27 adjacent the adjacent edge 32 or 34 of the face surface 27. The embodiment of wheel 10 shown in Figures 1 and 2 includes two support parts 36 20 adjacent the edges 32 and 34 of the wheel 10. The contact portion 24 may be constructed from any suitable material such as cloth or an elastomer such as natural or synthetic rubber having a Shore A durometer hardness preferably between 20 and 100.
25The support part 36 is adapted to reduce damage to the endless coated abrasive belt 17, since the support part 36 assures the maximum belt area in contact with the workpiece 4 at the edges of the contact wheel 10 and thus provides the lowest unit pressure at the edges 32 and 34 30 of the contact wheel 10. Lowering the unit grain pressure at the edg~s 32 and 34 of the contact wheel 10 tends to reduce the potential for shelling of the abrasive belt 17 resulting in extended life for the belt 17.
35The support part 36 also prevents damage to the contact wheel 10 and provides an increased cut rate as the support part 36 provides support for the land parts 2 0 ~ 2 of the peripheral face surface 27 to reduce undesirable flexing. The reduced flexing of the lands diminishes the potential for fatigue damage to the lands, particularly at their roots or bases.
Should a belt 17 fail to track properly (e.g.
a mistract) and expose an edge 32 or 34 of the wheel 10 to direct contact with the workpiece 4, the support part 36 assures the maximum edge area in contact with the worXpiece 4 and thus provides t~le lowest unit pressure at 10 the edges of the contact wheel 10 to thereby deter breakage or other damage to an edge 32 or 34 of the contact wheel 10 or to the workpiece 4. The support part 36 also acts as a barrier to restrict penetration of the belt 17 and workpiece 4 into the grooves 53 at the edge 15 32 or 34 of the contact wheel lo reducing the potential for impact between the workpiece 4 and wheel 10.
~ he surface area ratio of the lands to grooves will depend on the particular abrading application and may typically range from 1:9 to 9:1. An exampl~ of a 20 wheel according to the embodiment shown in Figure 1 may have a diameter from the axis of the hub 11 to a radially outer point on a land on the peripheral face surface 27 of approximately 35.7 centimeters with and overall width of the face surface 27 between ends 32 and 34 of about 25 7.6 centimeters and with the width of each of the support portions 36 ~eing approximately 1.25 centimeters. The width of an individual land may be approximately 0.95 centimeters and the width of an individual groove may be about 0.95 centimeters. It should be noted that these 30 dimensions are for purposes of describing the invention and are not intended to be limiting.
Figure 3 illustrates a second alternative embodiment of contact wheel according to the present invention with the contact wheel generally designated by 35 the reference character 20 which has many parts that are esRentially the same as the parts of the contact wheel 10 and which have been identified by the same reference number to which the suffix "A" has been added.
Like the contact wheel 10 described in Figures 1 and 2, the contact wheel 20 shown in Figure 3 comprises 5 a hub having an axis and a generally cylindrical peripheral surface about the axis. The hub includes surfaces defining an arbor hole for mounting the wheel 20 on a drive mechanism.
The contact wheel 20 also comprises a generally 10 monolithic contact portion 2~A having a cylindrical inner sur~ace coaxial with the hub and mounted on the peripheral surface of the hub, and an outer cylindrical coaxial peripheral face surface~27A having axial spaced edges 32A and 34A. The contact portion 24A has 15 circumferentially spaced parallel elongate grooves 53A
having opposite ends 54A and 56A. The grooves 53A are recessed from the face surface 27A with land parts of the peripheral face surface 27A disposed between the grooves 53A. The contact portion 24A has both ends 54A and 56A
20 of each o~ the grooves 53A spaced from the adjacent edges 32A and 34A of the face surface 27 to provide a relatively narrow continuous support part 36A adjacent one edge 34A of the peripheral face surface 27A and a relatively wide continuous support part 72 adjacent the 25 other adjacent edge 32A of the face surface 27A.
The contact wheel 20 has a width W and a diameter Y. The width W may range from approximately 1.5 inches (3.8 centimeters) to about 100 inches (254 centimeters) and the diameter Y of the wheel 20 may range 30 from about 2 inches (5.1 centimeters) to approximately 30 inches (76.2 centimeters).
Unlike the contact whsel 10, the contact wheel shown in Figure 3 comprises a relatively wide continuous support part 72 having a length X. For 35 example, a contact wheel with a diameter of 14 inches (35.7 centimeters) and a width of 6 inches (15.2 centimeters) may have a relatively wide continuous C~
- 13 ~
support part 72 with a length of 3 inches (7.6 centimeters). The relatively wide continuous support part 72 is particularly suitable for use in a method of abrading a workpiece using a single contact wheel which 5 is discussed later in this application.
The support parts 36A and 72 are adapted to reduce damage to the endless coated abrasive belt 17, since it is believed that the support parts 36A and 72 assure the maximum belt are.a in contact with the 10 workpiece 4 at the edges of the contact wheel 20 to reduce the unit pressure at the edges 32A and 34A of the contact wheel 20. Similar to the support part 36 of the wheal 10, the support parts 36A and 72 also deter damage to the contact wheel 20 as the support parts 36A and 72 15 provide support for the land parts of the peripheral face surface 27A to limit their flexing.
Figure 5 illustrates a third alternative embodiment of contact wheel according to the present invention with the contact wheel generally designated by 20 the reference character 30 which has many parts that are essentially the same as the parts of the contact wha~l 20 and which have been identified by the same reference number to which the suffix "A" has been replaced by the suffix "B".
Like the contact wheel 20 described in Figure 3, the contact wheel 30 shown in Fiyure 5 comprises a hub having an axis and a generally cylindrical peripheral surface about the axis. The hub includes surfaces defining an arbor hole for mounting the wheel 30 on a 30 drive mechanism. The contact wheel 30 also comprises a generally monolithic contact portion 24B having a cylindrical inner surface coaxial with the hub and mounted on the peripheral surface of the hub, and an outer cylindrical coaxial peripheral face surface 27B
35 having axial spaced edges 32B and 74. The contact portion 24B has circumferentially spaced parallel elongate grooves 73 having an end 75 and an end 79. The grooves 73 are recessed from the face surface 27B with land parts of the peripheral face surface 27B disposed betwe~n the grooves 73. The contact portion 24B has the end 75 of each of the grooves 73 spaced from the adjacent 5 edge 32B of the face surface 27A to provide a relatively wide continuous support part 72B.
Unlike th~ contact wheels 10 and 20, the outer peripheral face surface 27B of the contact wheel 30 includes only a single support part 72B adjacent the edge 10 32B of the peripheral surface 27B. At khP other edge 74 of the peripheral surface 27B, the grooves 73 extend to the edge 74 of the wheel 30. The ratio of the diameter to the width of the contact wheel 30 may be approximately 4:1 and is particularly suitable for use with a 15 relatively wide belt abrasive, such as an abrasive with a width of 14 inches (35.56 centimeters) or qreater.

OPERATION
The present invention may also be described as 20 a method of abrading a workpiece using a single contact wheel comprising the steps of (1) providing a hub having an axis and a generally cylindrical peripheral surface about the axis, ~2) providing a g~nerally monolithic contact portion having a cylindrical inner surface 25 coaxial with the hub, and an outer cylindrical coaxial peripheral face surface having axial spaced edges, (3) mounting the cylindrical inner surface of the contact portion on the periphsral surface of the hub, (4) providing the contact portion with circumferentially 30 spaced parallel elongate grooves having opposite ends, the grooves being recessed from the face surface with land parts of the peripheral fac~ disposed between the grooves, (5) spacing at least one end of each of the grooves from the adjacent edge of the face surface to 35 provide a continuous support part of the peripheral face surface adjacent the adjacent edge; (6) providing an endless coated abrasive belt adapted to grind the workpiece, (7) supporting the endless coated abrasive belt with the contact portion, (8) grinding the workpiece at a relatively high cut rate at a position generally adjacent the land parts; and (9) grinding the workpiece 5 at a different and relatively lower cut rate at a position gen~rally adjacent the continuous support part.
The embodiments of contact wheels shown in Figures 3 and 5 are particularly suitable for use in the method of abrading a workpiece using a single contact 10 wheel according to the present invention. The workpiece 4 may be a golf club formed by a casting process which leaves a casting gate or flash on the golf club. The operator may first grind the flash or gate from the golf club at an initially aggressive, high cut rate and 15 subsequently grind the surface of the golf club at a different relatively lower cut rate to provide a finer finish or smooth surface on the golf club.
U~ing the method and contact wheel of the present invention, the operator may first grind the golf 20 club at a position generally adjacent the land parts of the wheel 20; and then at a different and relatively low cut rate at a position spaced from the land parts (e.g.
adjacent the support part 72) to produce a finer, finished surface on the golf club. Tha user is spared 25 the additional task of using a different contact wheel (such as a plain-faced contact wheel) for the low cut rate/finer finish operation. Thus, an operator may accomplish two tasks without moving from a single grinding station. Thus, it is believed that the method 30 of the present invention may save operator time during some grinding operations.
The present invention has now been described with reference to several embodiments thereof. It will be apparent to those skilled in the art that many changes 35 can be made in the embodiment described without departing from the scope of the present invention. For example, the contact wheel of the present invention may comprise a shaped contact wheel including a hub having an axis, and a generally monolithic contact portion including an outer peripheral face surface having axial spaced edges which peripheral face surface is not cylindrical and 5 coaxial with the hub but which is instead intentionally shaped in the form of a new surface to be ground on a workpiece. Additionally, the contact wheels of the present invention may include grooves that extend completely around the periphery of the wheel, that are 10 generally coaxial with the axis of the hub and that do not include ends (e.g. the contact wheels sold by Minnesota Mining and Manufacturing, St. Paul Minnesota, under the trade designation 3M "Serr-X" T.M. Contact Wheels) so long as the wheel also includes at least one 15 end of other grooves being spaced from the adjacent edge of the face surface to provide a continuous support part of th~ peripheral face surface adjacent the adjacent edge. Also, the contact wheel of the present invention may comprise a contact portion having portions having a 20 different hardness or durometer ~e.g., the contact wheel 30 shown in FIG. 5 may have a serrated portion with a harder durometer than the plain faced portion).

Claims (8)

1. A contact wheel adapted to support an endless coated abrasive belt during abrasion of a workpiece comprising:
a hub having an axis and a generally cylindrical peripheral surface about said axis, a generally monolithic contact portion having a cylindrical inner surface coaxial with said hub and mounted on said peripheral surface of said hub, and an outer cylindrical coaxial peripheral face surface having axial spaced edges, said contact portion having circumferentially spaced parallel elongate grooves having opposite ends, said grooves being recessed from said face surface with land parts of said peripheral face disposed between said grooves, and at least one end of each of said grooves being spaced from the adjacent edge of said face surface to provide a continuous support part of said peripheral face surface adjacent said adjacent edge.

2. A contact wheel according to claim 1 wherein both ends of each of said grooves are spaced from the adjacent edges of said face surface to provide continuous support parts of said peripheral face surface adjacent both edges of said face surface.

3. A contact wheel according to claim 1 wherein the ratio of wheel width to wheel diameter is approximately 4:1.

4. A contact wheel according to claim 1 wherein said generally monolithic contact portion is constructed from an elastomer to at least partially conform to a shape of a portion of the workpiece.

5. A contact wheel adapted to support an endless coated abrasive belt during abrasion of a workpiece comprising:
a hub having an axis and a generally cylindrical peripheral surface about said axis, a generally monolithic contact portion having a cylindrical inner surface coaxial with said hub and mounted on said peripheral surface of said hub, and an outer peripheral face surface having axial spaced edges, said contact portion having circumferentially spaced elongate grooves having opposite ends, said grooves being recessed from said face surface with land parts of said peripheral face disposed between said grooves, and at least one end of each of said grooves being spaced from the adjacent edge of said face surface to provide a continuous support part of said peripheral face surface adjacent said adjacent edge.

6. A contact wheel according to claim 5, wherein said generally monolithic contact portion is constructed from an elastomer to at least partially conform to a shape of a portion of the workpiece.

7. A contact wheel adapted to support an endless coated abrasive belt during abrasion of a workpiece comprising:

a hub having an axis and a generally cylindrical peripheral surface about said axis, a generally monolithic contact portion having a cylindrical inner surface coaxial with said hub and mounted on said peripheral surface of said hub, and an outer peripheral face surface having axial spaced edges, said outer peripheral face surface comprising:
a land portion having surfaces defining a plurality of lands and grooves, said grooves being recessed from said face surface with said lands being disposed between said grooves, and at least one plain-faced portion adjacent an edge of said outer peripheral surface.

8. A method of abrading a workpiece using a single contact wheel comprising the steps of:
providing a hub having an axis and a generally cylindrical peripheral surface about said axis, providing a generally monolithic contact portion having a cylindrical inner surface coaxial with said hub, and an outer cylindrical coaxial peripheral face surface having axial spaced edges, mounting said cylindrical inner surface of said contact portion on said peripheral surface of said hub, creating circumferentially spaced parallel elongate grooves having opposite ends on said contact portion, said grooves being recessed from said face surface with land parts of said peripheral face disposed between said grooves, spacing at least one end of each of said grooves from the adjacent edge of said face surface to provide a continuous support part of said peripheral face surface adjacent said adjacent edge;
providing an endless coated abrasive belt adapted to grind the workpiece, supporting the endless coated abrasive belt with said contact portion, grinding the workpiece at a relatively high cut rate at a position generally adjacent said land parts; and grinding the workpiece at a different and relatively lower cut rate at a position generally adjacent said continuous support part.