US2638887A - Grinding wheel dresser - Google Patents

Description

y 9, 1953 G. EATON 2,638,887

GRINDING WHEEL DRESSER Filed Dec. 2, 1949 40 IN VEN TOR.

lIIIIIIIIIIIIIIIIIIIIII" IIIIIIII-IIIIIIII ATTORNEYS Patented May 19, 1 953 GRINDING WHEEL DRESSER George Eaton, Urbana, Ohio, assignor to The Desmond-Stephan partnership Mfg. 00., Urbana, Ohio, at

Application December 2, 1949, Serial No. 130,700

' This inventionrelates"to'grinding wheel dressers and more particularly to grinding wheel dressers of the ball'bearing'type,"

The purpose of a grinding-wheel dresser'is to restore the face of the'grinding wheel toproper condition which usually includes leveling'off the high spots so thatthe periphery will be within the desired limits as to uniformity, picking from the Wheel the'grainsjof abrasive material which have been loosenecL and at the same time producing such crushing of the other grains as to develop the proper and uniform surface conditions. One tool commonly used for this purpose is the diamond point dresser which essentially consists of a single point of adianiondwhith is moved across the'fa'ce of the-tool. The ball bearing dresser is another tool for the purpose and employs a set of dresser'cutter's' which has a much greater surface area, does not tend to h'eatiup as much as the diamond dresser-and has better picking properties. Further, since it will dress more wheels than the diamond'dressen' it is ordinarily more economical to use and will have a wider field of usefulness. Such ball bearing dressers are subjectedto severe conditionsof use, including the presence of'dust, the necessity for the parts to rotate at high speeds, which may be or the order 'of 10,000 to- 12,000 R. P; mam even above, and the severe wear and abrasion which occurs in the p'resence of such dust and such high rotational speeds as well as the substantial loads to which th'e'device is subjected. It is also important that provision'be' made for removing and replacing the dresser-cutters and assuring that such'replacement can beaccomplished readily and simply andwithout the need for special tools or skills in doing so.

In accordance with thepresent invention a' b'all bearing grinding wheel: fdresser is provided "in which the bearings "are sealed, preventing access of dust thereto, the bearings beingassembled'in .a sleeve on which the set" of dressingfcutter's is mounted for ready removal" andireplacement. The entire rotating assembly is protected against access of dust, and .is so handled during assembly as well as in use that axial thrust-loads are reduced to a minimum. In use, as the dresser is moved across the face of the grinding wheel, the axial thrust istransmitted directly from the inner races of the ball bearings to the tool head or support. The removal and replacement of the assembly of cutter'is-a simple matter, and provision is made so that the assembly may be tightened to any degree desired when replacing it in the head, without in any way applying a load to the bear,-

ings themse1ves.;. Thus the tighteningyqi the as-.

14 'Claims. (Cl. 125-'--37) sembly to secure it in position cannot apply any load to'the' bearings or in any way impair the freedom of operation thereof. Such thrust loads as "occur-in the tightening operation are carried by direct engagement of the inner races of the bearing members themselves, such members being stacked against each other in direct contact, thus assuring the maximum of freedom of operation of the bearings and the ease and convenience in the removal of the assembly and the replacement of the dresser cutters thereon.

It isaccordingly the principal object of the invention to providea grinding Wheel dresser of the ball bearing type in which the set of dressing cutters maybe easily changed, which does not require careful adjustment in removing or replacement of the cutters, in which it is not possible to improperly load the bearings either during the assembly of the bearings into the sleeve or in the replacement of the cutter assembly.

It is also an object to provide such a ball bear ing grinder wheel dresser in which the inner races of the bearings are stacked in direct load transmitting' relation with each other and in similar relation with the stationary'head in which the dresser is mounted to provide for the transmission ofboth the initial stacking loads and the axial loads developed'during use.

"It is also an object to provide such a dresser in which relatively large surface areas are provided for guiding the'assembly and holding it in pre-- determined position while additional surfaces provide ior taking'the axial thrust to maintain the assembly in proper working relation.

It is astill further object to provide such a dresser in which all of the working parts are in accordance with the present invention.

' Fig. 2 is a perspective view of a sealed ball bearing ofatype suitable for use with the present invention. H

,Figs. 3,5 and 5 are views similar to Fig. 1 showing a series of successive step in the manufacture of the dresser; and

Fig. 6 is an elevationalview with parts broken away showing the finished dresser assembly mounted in the head and properly located between the two projecting portions thereof, in final operative position.

Referring to the drawings which disclose a preferred embodiment of the invention, it is preferred to utilize sealed ball bearings which are shown generally at ID and which comprise an inner race II and an outer race l2, the bearing being so constructed that the side faces thereof are completely enclosed thus preventing dust or dirt from finding its way into the actual ball receiving areas. The outer race I2 is shown as having an offset seal cover l3 which however is of lesser axial extent than the inner race ll. As a result, when two such ball bearings are stacked one against the other, contact will be made between the adjacent ends of the inner races H, leaving the outer races l2, [3 free of contact with each other.

The first step in the manufacture of the device is to place one such bearing In in predetermined position within the sleeve l5. The

sleeve has a shoulder or collar I 6 at one end and is threaded as shown at 11 adjacent the other end, the main portion of the cylindrical surface thereof providing for receiving the set of dresser cutters thereon.

It is important in assembling the device that the bearings be placed in position in the sleeve with a sufficiently tight press fit so that they will be firmly retained in operative position, but it is also important to provide for accomplishing such insertion without applying a material load to the bearing itself. If the entire force required to press the bearing into position in its sleeve were required to be transmitted through the bearing itself, damage would be likely to result, leading to increased possibility of failure of the bearing in use. Accordingly provision is made for inserting the bearings into position in the sleeve in such manner that the bearing itself remains substantially unloaded.

The first step in this operation is shown in Fig. l in which the sleeve is mounted upon a tool in the form of a die 20 which has an outer guide'flange 2| over which the sleeve is received in order to properly and accurately locate the position thereof. The die also has a central upstanding annular fiange 22 of the proper diameter to engage against the inner race II of the bearing. A second tool in'the form of die 25 is formed with an outer annular portion 26 adapted to engage against the outer race of the bearing, i. e., that part which is in direct contact with the sleeve. Die 25 also has an inner annular raised portion 21 of the same diameter as portion '22, and thus in position to engage against the inner race ll of the bearing. The two portions 26, 21 are axially offset from each other the same amount as the corresponding parts of the bearing itself are offset so that such portions will simultaneously engage against the outer race l2 and the inner race of the bearing, respectively.

Initially the bearing is placed at the top of the sleeve then put in a press which forces die 25 downwardly, such action providing for the downward travel of the bearing wholly under the force applied through flange 26 against the outerrace of the bearing. Since the only resistance to downward travel is the frictional engagement of the outer race against the inner surface of the sleeve, it is obvious that no axial loading of the bearing will occur in this operation.

When the bearing reaches its final desired position, its lower race I I will be brought into con- 4 there will be a direct driving engagement between the fiange 21 of die 25 and the inner race of the bearing, which will force the bearing into its final desired position but without substantially loading the bearing itself since flanges 26 and 2'! occupy the proper relation to each other so that both inner and outer races will be moved together'and will cause the bearing to-occupy the ultimate desired position without at any time developing any thrust across the bearing itself.

The next step is shown in Fig. 3 in which the second bearing is similarly pressed into position in the sleeve, the same operation taking place as before except that the lower bearing is now supported directly against flange 22 and the upper bearing is pressed into position until its inner flange ll contacts the axially extending inner flange ll of the lower bearing. This fixes accurately the position of both bearings in the sleeve with their inner races in direct engagement with each other but without at any time having applied a load to either bearing itself. If a ball bearing is used in which the inner race does not project axially beyond the outer race, suitable change may be made in the relative positions of the flanges on-the tools, and a sleeve or washer may be inserted between the adjacent faces of the inner races of the two bearings in order to assure direct contact or stacking of each such race against the other.

A pin 3|] is then inserted through the inner bearing races of the two bearings by a suitable tool indicated at 31. The thrust in this case is developed upon the inner bearing races but as will be evident from Fig. 4 these two races are supported in direct engagement with each other and the inner race ll of the lower bearing is still supported directly upon flange 22. Thus it is possible to force the pin through the inner races of both bearings, the pin extending into the bottom of the recess 32 formed in die 20, such recess determining the final position of the pin, and without at any time applying a load to either bearing itself. It is not necessary that the pin have a tight enough fit to be capable of transmitting the axial thrust loads on the dresser and hence only a moderately close fit is preferred which does not result in any undesirable stress or deformation within the bearings.

Thereafter the sleeve may be removed from the dies and the set of dresser cutters indicated at 35 may be stacked on the sleeve, the sleeve having a slot or keyway 35 adapted to interfit with keys on the set of cutters in order to properly locate and fix the cutters in relation to the sleeve. A washer 38 is next assembled at the end of the set of cutters, the washer having suitable tangs 39 which are adapted to be bent over into notches formed in the nut 40 which nut is threadedly received on the portion I! of the sleeve. After the nut 40 has been tightened against the washer, one or more of the tangs 39 are pressed down into the notches in the nut as shown at the right-hand side of Fig. 5, thereby securely locking the cutter discs in position.

A pair of dust rings 45 are next assembled by sliding them over the pin, these rings being in the form of metal plates which fit upon the pin and have a running clearance with the inner circumference of the sleeve in order to allow free rotation of the sleeve while at the same time preventin objectionable passage of dust or dirt therebetween. The rings 45 have direct bearing engagement with the outer ends of the inner races H and like the pin 30, remain stationary tact with the flange 22 of die 20. At this t l 7s during use with the sleeve and set of cutters thereon rotating relative thereto; There is clearance between such rings 45 and all portions of the outer. races of the bearings.

The structure as shown in Fig. 5 represents the dresser assembly and may be supplied as a unit to be replaced for similarworn units by the ultimate users. :Ass-hown in Fig. 6 the assembly is adapted to be mounted in a head indicated generally at .50 comprising spaced arms 5| each of which is bored and threaded to receive the hollow bolts 52. One such bolt may be threaded directly into the arm 5| while a lock nut 53 is preferably used upon at least one of the arms to facilitate setting such bolt in predetermined relation to the dresser assembly to hold the same in operative position. The shank of each of these bolts is bored to form a hollow as indicated at 55 and there is thus provided an-inner cylindrical portion 56 which is of proper dimensions to receive and removably support the extending cylindrical ends of pin 30 over a substantial hearing area. As shown in Fig. 6 there is preferably a clearance between both ends of pin 30 and the hollow portions 55 and hence there is no axial thrust upon the ends of pin 30.

In order properly to locate the assembly in the head and to transmit the axial thrust thereof, each bolt 52 has the annular projecting portions 5'! radially outwardly of the pin, such portions having direct bearing engagement with the dust rings 45, respectively. As already described the dust rings are in direct contact with the outer ends of the inner races H of the bearings respectively, while the adjacent ends of the inner races of the bearings are themselves in direct bearing engagement, thus presenting a solid stacking from one bolt to the other. It will be evident therefore that the bolts 52 may be tightened as much as desired, and that this tightening action does not apply a stress to the pin nor does it in any manner apply a load on the bearings. The thrust is transmitted in a solid stacked relation from one bolt, through the dustring; the inner race of one bearing, theinner race of the other bearing to the other dust ring and finally to the annular surface of the opposite bolt. It is thus clear that the bearings cannot. be loaded and that they continue to operate in the normal manner. regardless of the pressure or axial thrust load developed in mounting the asa pin, the damage due to the dust and high speed rotation are effectively minimized. In order to maintain. freedom of running of the bearings where both the inner and outer races are force-fit it is found desirable to use what-is known in the trade as loose bearings.-

Production of the parts of the present invcntion and assembly thereof into the completed device are greatly simplified and. greater accuracy in alignment is made possible because the inner surface of the sleeve is may be ground so that when the bearings are pressed thereintothey will be accurately aligned, and similarl'ythe ends of hollow bolts 52 may be flat ground to maintain the assembly in proper running alignment. The slight clearance between the pin 38 and the bore of the hollow boltsprovides 'for accuracy of alignment of these ground surfaces and at the same time makes possible the ready removal "and replacement of the assembly.

The invention thus provides a simple and highly satisfactory ball bearing grinding wheel dresser which has prolonged useful life, in which the loading on the bearing is reduced oreliminated, and in which removal and replacement of. the dressing cutters is made a simple operation and one which does not require special skill or tools nor result in objectionably varying or loading the thrust upon the bearings themselves.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. A grinding wheel dresser comprising a, head, a dresser assemblyrotatably supported in said head and including a sleeve, a set of dresser cutters onysaid sleeve, a plurality of separate ball bearings mounted within said sleeve having inner and outer races, said outer races being mounted in said sleeve in spaced relation with each other, a pin directly fitting in andprojecting through both said-inner races, means inde-- pendent of said pin establishing direct bearing engagement between adjacent ends of the inner races of said bearings, and pressure applying means carried by said head in spaced relation with said-sleeve and having direct thrust transmitting engagement with the two outer ends of said inner bearing races respectively to apply axial pressure thereto to locate and secure said assembly within said head.

2. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head and including a sleeve, a set of dresser cutters removably and replaoeably mounted on said sleeve, a plurality of separate sealed ball bearings mounted within said sleeve having inner and outer races, said outer races being mounted in said sleeve in spaced relation with each other, a pin directly :fitting in and projecting through bothsaid inner races, means inde pendent of said pin establishing direct bearing engagement between adjacent ends of the inner races of said bearings, and pressure applying means carried by said head in spaced relation with said sleeve and said outer races and having direct thrust transmitting engagement with the two outer ends of said inner bearing. races respectively to apply axial pressure thereto'to 10-- cats and secure said assembly within said head.

3. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head and including a sleeve, a set of dresser cutters on said sleeve, a plurality of separate ball bearings mounted within said sleeve having inner and outer races, said outer races being mounted in said sleeve in spaced relation to each other, means establishing direct bearing engagement between adjacent ends of said bearings, a pin on which the inner races of said bearings are mounted, means carried by said head for removably receiving the cylinder surface of said pin and rotatably supporting said assembly on said head, and additional means having direct thrust transmitting engagement between said head and said inner bearing races to transmit the axial thrust thereof independently of said pin.

. 4. A grinding wheel dresser comprising 'a head, a dresser assembly, rotatably supported in said head including'a sleeve, a set of dressing cutters on said sleeve, a pair of ball bearings within said sleevehaving inner and outer races, said outer 7 races being mounted in said sleeve in spaced relation with each other, means establishing direct bearing contact between said inner races, a pin extending through said inner races, hollow end bolts on said head receiving the cylinder surface of said pin for supporting said assembly in said head, and means in direct bearing engagement with said inner races respectively for locating said assembly axially of said head and transmitting the thrust thereof independently of said pin.

5. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head including a sleeve, a set of dressing cutters on said sleeve, a pair of ball bearings within said sleeve having inner and outer races, said outer races being mounted in said sleeve in spaced relation with each other, means establishing direct bearing contact between said inner races, a pin extending through said inner races, dust rings on said pin in direct bearing engagement with the outer ends of said inner races, means carried by said head for removably receiving the cylindrical surface of said pin and rotatably supporting said assembly on said head, and additional means having direct bearing engagement between said head and said dust rings respectively to transmit the axial thrust thereof independently of said pin.

6. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head including a sleeve, a set of dressing cutters on said sleeve, a pair of ball bearings within said sleeve having inner and outer races, said outer races being mounted in said sleeve in spaced relation with each other, said inner races being in direct bearing engagement with each other, a pin extending through said inner races, dust rings on said pin in direct bearing engagement with said inner races respectively, hollow end bolts on said head removably receiving a substantial bearing area of said pin for supporting said assembly in said head, and means in direct bearing engagement with said rings for fixing said assembly axially of said head and transmitting the thrust thereof independently of said pin.

'7. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head including a sleeve, a set of dressing cutters on said sleeve, 9, pair of ball bearings within said sleeve having inner and outer races for said bearings, said outer races being mounted in said sleeve in spaced relation with each other, said inner races having reater axial extent than said outer races and being in direct bearing engagement with each other, a pin extending through said inner races, dust rings on said pin in direct bearing engagement with said inner races respectively, hollow end bolts on said head removably engaging over a substantial area of said pin for supporting said assembly in said head, and means in direct bearing engagement with said rings for fixing said assembly axially of said head and transmitting the thrust thereto independently of said pin.

8. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head including a sleeve, a set of dressing cutters on said sleeve, a pair of sealed ball bearings press fitted into said sleeve, said bearings having outer races mounted in said sleeve in spaced relation with each other and having inner races in direct bearing engagement with each other, a pin extending through said bearings, a pair of thrust bolts mounted in said head removably supporting said pin on the cylindrical surface thereof, and additional means on said head engaging. the outer ends of said inner races'and free of lateral contact with said pin to transmit the axial load on said assembly independently of said pin.

9. A dresser assembly for a grinding wheel dresser which comprises a sleeve, a set of dresser cutters on said sleeve, a plurality of separate ball bearings mounted within said sleeve, said bearings having outer races mounted in said sleeve in spaced relation with each other, means establishing direct bearing engagement between adjacent ends of the inner races of said bearings, a pin extending through said inner races, and dust rings slidable over said pin on opposite sides of said bearing in direct axial thrust transmitting engagement with the inner races of said bearings respectively and in spaced relation with said sleeve.

10. A dresser assembly for a grinding wheel dresser comprising a sleeve, a set of dressing cutters removably and replaceably mounted on said sleeve, a pair of sealed ball bearings having outer races press fitted into said sleeve in spaced relation with each other, said bearings having inner races in direct bearing engagement with each other, a pin press fitted into said inner races and extending from opposite sides thereof, and dust rings slidable over said pin having direct axial thrust transmitting engagement with said inner races of said bearings respectively and spaced from the adjacent portions of said sleeve.

11. A dresser assembly for a grinding wheel dresser comprising a sleeve, a set of dressing cutters on said sleeve, a pair of sealed ball bearings having outer races press fitted into said sleeve in spaced relation with each other, said bearings having inner races of greater axial extent than said outer races and stacked in direct bearing engagement with each other, a pin press fitted into and extending through said inner races leaving said bearings substantially free of axial thrust loading, and means slidably mounted on said pin out of contact with said sleeve and having direct bearing engagement with the outer faces of said inner races respectively for transmitting axial thrust by direct contact from one of said inner races to the other independently of said pin.

12. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head including a sleeve, a set of dressing cutters on said sleeve, a pair of sealed ball bearings having inner and outer races, said outer races being press fitted into said sleeve in spaced relation with each other and said inner races having greater axial extent than said outer races and being in direct bearing engagement with each other, a pin press fitted into and extending through said inner races leaving said bearings substantially free of axial thrust loading, and dust rings slidably mounted on said pin outwardly of said bearings having direct bearing engagement with the outer ends of said inner bearing races respectively to enclose said bearings and to transmit axial thrust loads between said bearings and said head independently of said pin.

13. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head including a sleeve, a set of dressing cutters on said sleeve, a pair of sealed ball bearings having inner and outer races, said outer races being press fitted into said sleeve in spaced relation with each other and said inner races being in direct bearing engagement with each other, a pin press fitted into and extending through said inner races leaving said bearings substantially free of axial thrust loading, hollow end bolts on said head receiving and rotatably supporting the cylindrical surface of said pin in said head leaving said pin free of axial thrust, and means on said head adapted to be tightened directly against said inner races respectively for locating said assembly axially of said head and transmitting the axial thrust thereof independently of said 14. A grinding wheel dresser comprising a head, a dresser assembly rotatably supported in said head including a sleeve, a set of dressing cutters on said sleeve, a pair of sealed ball bearings having inner and outer races, said outer races being press fitted into said sleeve in spaced relation with each other and said inner races being in direct bearing engagement with each other, a pin press fitted into and extending through said inner races leaving said bearings substantially free of axial thrust loading, dust rings on said pin in direct bearing engagement with said inner races respectively, hollow end bolts on said head 10 receiving and rotatably supporting the cylindrical surface of said pin in said head leaving said pin substantially free of axial thrust loads, said nuts having portions in direct bearing engagement with said rings radially outwardly of said pin for fixing said assembly axially of said head and transmitting the thrust thereof independently of said pin.

GEORGE EATON.

References Cited in the file of this patent UNITED STATES PATENTS

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