US1767321A - Abrasive wheel - Google Patents

Description

June 24, 1930. H. F. SKILLINGS 1,767,321

ABRAS IVE WHEEL Filed April 16, 1928 In veniqifl HavoZdFSi/Z s,

y am wgw gg for illustrative purposes,

Patented June 24, 1930 UNITED STATES PATENT OFFICE HAROLD F. SKILLINGS, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOS TO THE BLAN- CHABD MACHINE COMPANY, OF CAMBRIDGE, MASSACHUSETTS, 'A CORPORATION OF MASSACHUSETTS I ABRASIVE WHEEL Application filed April 1c, 1928. Serial no. 270,461.

by rivets 10 extending through both walls and through the partitions.

This invention relates to a novel and improved abrasive wheel, of the class in which several blocks or segments of abrasive matedivide the annular groove 9 into a series of rial are adjusta-bly and removably mounted arcuate chambers for theabrasive blocks new in the chuck or holder, in which they-may be to be described. adjusted from time to time as they wear Each of the chambers receives a pair of away, and mayfinally be removed and reabrasive blocks or segments 11", which, in the placed by new ones. present example, are arcuate,that is to say,

The invention will be best understood by they are convexly curved on their facesto I} reference to the following description, when taken in connection with the accompanyin are elm e circumferentially see Fig. 2), and o hl y gare required; This reduces Fig. 1 is an elevation of an abrasive wheel the cost of manufacture of the wheel, and inexemplifying the invention; creases the strength of the blocks against lat- Fig. 2 is a of the same as viewed *eral stress orinward thrust of the work as the from below; latter is passed across the face of the wheel.

Fig. 3 is a sectional View, on an enlarged In the present'example, the ends of each scale, on line 3-3 of Fig; 2; and block are rounded as at 12, thereby to give 7 F lg. 4 isa sectional view on line 44 of them a fair bearing, and to make them selfaligning, as will presently appear. Each of the partitions 6 has two curved seats or bearbodiment .of the invention which is selected ing surfaces 13 for the adjacent ends of the there is shown an blocks. These seats and the ends of the blocks abrasive wheel comprisingabody 5, which in are formed on arcs struck from centers A. practice is a steel forging, herein annular Each seat-13, therefore, constitutesafulcrum, in form, intended to be mounted on a face on which the block may be rocked aboufi'an plate to be secured to the spindle of a grlnfllaxis represented by the point A in Fig. 2. 111g machine, such as a vertical splndle sur- In lik ann r, th oth r end of each block face grinder. is rounded as at 12, on an arc struck from The body presents a plurality of abutthe point B. Between the adjacent ends 12' Inentsti, herein three, equally spaced part1 f h i f bl k th r i rovid d xtions, and an outer Wall 7, herein anH pansive'means to urge such blocks, respectivedisposed about said abutment-s. In the presl i o jt 'di ti' n a ain t th abut ent example, the body presents also an inner wall 8, herein annular, and separated from the outer wall by an annulargroove' 9. The

In the drawings:

i teferring to the drawings, and to the empurposes :first, it strengthens the body and'f-contacts with a shoe 15, having an areshaped seat 13'; which fits the end of the block, and is formed on an arc struckfrom top, down to the bottom of the body before the point B as a center.

the water flies outwardly. This helps to keep dirt'out of the chuck, and to bring the Wa er suitable means for forcing the shoes 15 apart, nearer to the wheel face. Herein, the abutthe same in the present exam 1e comprising ments or partitions 6 are formed as sepaa wed e 16, having upwardly converging rate pieces, inserted between the inner and faces 1 which enga corresponding com 00 outer walls, and suitably secured in place, as verging faces on the Engagement of 1 Referring now to Fig. 3, there is providea. ea,

the shoes with the wedge isconveniently maintained by a U-shaped spring 18, having arms 19 suitably secured to the shoes, as by providing the latter with slots 20, in which the arms are secured by screws 21.

The shoes are forced apart in opposition to the spring by appropriate means,'herein a screw 22, threaded into a block 23, and extending loosely through a much larger opening 2a provided in the wedge 16, which is also chambered out as at 25, to receive a head 26 and an annular shoulder or collar 27 on the screw. The inner end of'this chamber thus provides a seat against which the thrust of the collar 27 may be exerted to cause the wedge to be moved in an upward direction, and to force the shoes apart when the screw is rotated in the proper direction by the application of a socket wrench to the head 26.

The described operating mechanism is held in place, and is prevented-from dropping out by securing the block 23 to the body 5. This is conveniently accomplished in the present example by the provision of a screw 28 (see Fig. 4) extending loosely through a hole 29 provided in the body, and threaded into the block 23, the head of the screw being received in a chamber 30 counterbored into the body. The block also constitutes a convenient means for holding the spring 18 in place, said block for this purpose being provided in its upper end with a shallow roove 31, which receives the base of the spring. The shoes and the wedge constitute a floating assembly capable of movement radially and circumferentially, considered with reference to the axis of the body.

Referring now to Fig. 2, the blocks of each pair may be likenedto two links constituting a toggle, and the expansible assembly may be c nsidered as a toggle-actuating mechanism, capable of swinging the adjacent ends of the blocks in an outward direction against the stop or limiting means presented b the outer annular wall 7. In Fig. 2, the points A and B, representing the pivotal axes at the ends of one block, have been connected to each other by a line AB, while the points'B have been-connected to each other by a line 13-13. In expanding the operating mechanism, the line B-B naturally lengthens, as a consequence of which the links represented by the lines A-B, A-B, swing outwardly about the points A. At the same time, the expansible mechanism urges the blocks against the seats presented by the abutments 6. While the movement of the shoe 15 actually is tangential, the large angle subtended by each block is such that there is an outward componentof the force tending to press the outer surface of the block firmly into contact with the inner circumferential surface of the surrounding wall. Naturally, this is augmented by the action of centrifugal force when the wheel is rotating.

The structure is characterized by a symmetrical formand arrangement of the several segments or blocks, and corresponding forces. Inasmuch as the ends of the blocks are rounded, there is no tendency to chip or break away, as there would be if they were angular. Moreover, this form ofthe blocks is advantageous because, as already stated, they are self aligning. One factor in this is the employment of the shoes between the blocks and the wedgewhich forces them apart. The rubbing action of the wedge against the shoes introduces very little frictional resistance, while the rubbing of the ends of the blocks against the arc- shaped seats 13 and 13 is so slight as to be negligible.

The blocks are held so firmly that no positive stop is required behind them to keep them from being pushed back into the wheel body, after they have been worn away to such an extent as to require adjustment in an outward direction, it being understood, of course, that new blocks extend the full depth of the annular groove in the body. While it is ossible to introduce s acers, such as bloc s of wood or metal, behind the segments, this is found to be unnecessary in practice. As the clamping and centrifugal forces are considerable, it is quite probable that there-is distortion of the outer wall 7 sufficient to make its curvature agree with the curvature of the segments, provided there should be any slight difference initially.

Having thus described one embodiment of my invention, but without limiting myself thereto, what I claim and dsire by Letters Patent to secure is:

1. In an abrasive wheel, the combination of a body having inner and outer, annular walls and an intermediate, annular groove; a plurality of partitions connecting said walls to each other at intervals and dividing said groove into a plurality of arcuate chambers, each partition presenting on each side thereof an arc-shaped abutment; a plurality of arcuate, abrasive segments arranged in pairs, one pair in each chamber, each segment having ,two arc-shaped ends, each "resting a ainst one of said arc-shaped abutments; each segment having an arc-shaped surface engaging said outer annular wall; and" expansible means between the two adjacent ends of the segments of each pair, each expansible means including two shoes, each presenting an arcshaped abutment which engages the adjacent, arc-shaped end of one of said segments; a wedge between and engaging said shoes, 9. U- shaped spring secured to said body and having two arms secured to said shoes, respectively, and tending to move them toward each other, and a screw for moving said wedge relatively to said shoes to force them apart. 1

2. In an abrasive wheel, the combination of a body having inner and outer annular wedge between and rock said walls and an intermediate annular groove; being between and contacting'with two ful a plurality of partitions connecting said walls to each other at intervals anddividing said groove into a plurality of arcuate chambers; a lurality of arcuate abrasive blocks arrange in pairs, one pair in each chamber, each block having one end resting against one of said partitions; and expansible means two adjacent ends of the blocks each. expansible means includ between the of each pair, ing two shoes engaging such adjacent ends, a

screw said shoes to force them apart and to urge the other ends of said blocks against said parti-r tions, and to urge said outer wall, and spring maintain engagementof said intervening wedge.

3. In an abrasive wheel, the combination of a body having inner and outer, annular walls and an intermediate, annular groove a plurality of partitions connecting said walls to each otherat intervals and dividing said groove into a plurality of arcuate chambers, each partition presenting two oppositely facing fulcrums; a plurality of arcuate, abrasive segments arranged in pairs, one pair in each chamber, mounted to rock on oneof said fulcrums and an arc-shaped surface engaging the inner cirblocks against. said shoes with the cumferential surface of said outer, annular" wall and expansible means between two adjacent ends of the segments of each pair to rock said segments on their fulcrums outwardly toward said outer wall.

4:. In an abrasive of a bod having an annula'r'wall and a plurality o fulcrums within the circle of said wall; a plurality of abrasive segments, each having rocking contact with one of said fulcrums and adapted to engage the inner circii'mferential surface of said wall; a plurality of shoes, each having rocking contact with one of said segments; a plurality of wedges each contacting with one of said shoes; and a plurality of wedge-actuating screws for callsing said wedges to act through said shoes to blocks, respectively, ward said fulcrums.

6. In an abrasive wheel, the combination of a body presenting a plurality of fulcrums and a wall about said fulcrums; a plurality of abrasive blocks arranged in pairs, each pair engaging said shoes, 21- for moving said wedge relatively. to-

means tending to.

each segment having an end wheel, the combination abutments; and

segments on their fulcrums outcrums and with said wall; and expansible means between and having pivotal connection with two adjacent portions of the blocks of each pair to rock such blocks on their fulcrums and to urge such blocks, respectively, in opposite directions against said two fulcrums and outwardly againstsaid wall, I

7. In an abrasive wheel, the combina'ticu'of a body presenting a plurality of-fulc'rums;

a: plurality of abrasive blocks arranged-in being between two fulcr'ums';

pairs, each pair and expansible means between two adjacent portions of the blocks "of-each pair to rock such blocks such blocks,

tions toward and aIwedge between said shoes.

blocks arranged" in shoes apart. a 1 g 9. In an abrasive wheel, the combination of on their fulcrumsga'nd to urge respectively, in opposite direc"- said 'fulcrums,"said expans'ible means including two shoes :havingipivotal 1 connection with said portions, respectively,

11 an abrasive wheel, the'combinatio'n of a body presenting a plurality of abutment's';

between-='twoabutof the blocks of i each pair, yielding means tendin'g to "move" said shoes'together; and means to I'H'OVG'Slid a body presenting a plurality of abutments a plurality of abrasive blocks arrangedin pairs; between two abutments'ytwo respectively, with two ad each pair being shoes contacting, jacent surfaces of the blocks of each pair, yielding means tending to move said shoes together; and a'wedge screw tomove said shoes apart.

10 In an abrasive wheel, the combination of a rotatable body presenting'a plurality of abutments; a plurality of abrasive blocks arranged in pairs, each pair being between two expansive means between two adjacent surfaces of the blocks of each pair to urge them apart, said means including shoes contacting with said surfaces, yield- 'lIig means tending to move said shoes together, wedges between the shoes of each pair and movable lengthwise of theaxisof rota tion of said body, and wedge-actuating screws extending lengthwise of said axis.

11. In an abrasive wheel, thecombination of a rotatable body presentinga plurality of abutments; a plurality of abrasive blocks ar ranged in pairs, each pair being between two abutments; andexpansive'means between two adjacent surfaces of the blocks of each pair to urge them apart, said means including shoes contacting with" said surfaces, a U- shaped spring having two arms connected to said shoes and tending to move said shoes together', wedges between the shoes of each pair and movable lengthwise of the axis of rotation of said body,

arms of each spring, means securing said and wedge operating blocks between theblocks and said springs to said body, and wedge-actuating screws extending lengthwise of said axis and having screw-threaded engagement with said blocks, respectively.

12. In an abrasive wheel, the combination of a body presenting a plurality of abutments constituting fulcrums, a plurality of abrasive blocks arranged in pairs, each pair being between two abutments and constituting a toggle; means to swing the blocks of each pair in an outward direction about their fulcrums; and means to limit such swinging.

13. In an abrasive wheel. the combination of a body resenting a plurality of abutments constituting fulcrums, a plurality of abrasive blocks arranged in pairs, each pair being between two abutments and constitutin a toggle; means between two adjacent en s of t e blocks of each pair to swing the blocks of each pair in an outward direction about their fulcrums; and means to limit such swinging.

14. In an abrasive wheel. the combination of a body presenting a plurality of abutments constituting fulcrums; a plurality of abrasive blocks arranged in pairs, each pair being between and contacting with two abutments and constituting a toggle; expansible means between two adjacent ends of the blocks of each pair to urge said blocks, res ectively, in opposite directions against said abutments and to swing said blocks in an outward direction about their fulcrums: and means to limit the outward swinging of said blocks.

15. In an abrasive wheel, the combination of a body presenting a plurality of abutments constituting fulcrums; a. plurality of abrasive blocks arranged in pairs, each pair being between and contacting with two abutments and constituting a toggle; expansible means between two adjacent ends of the blocks of each pair to urge said blocks, respectively, in o posite directions against said abutments an to swing said blocks in an outward direction about their fulcrums; and a wall about said blocks to limit their outward swinging movement.

16. In an abrasive wheel, the combination of a body presenting a plurality of abutments constituting fulcrums; a plurality of abrasive blocks arranged in airs, each pair being between and contacting with two abutments and constituting a toggle; and expansible means between two adjacent ends of the blocks of each pair to exert a pressure against said ends and to operate said toggle.

17. In an abrasive wheel, the combination of a body presenting a plurality of abutments each having an arc-shaped seat constituting a fulcrum; a plurality of abrasive blocks arranged in airs, each pair being between two seats an each block having an arc-shaped end seated in one of said areshaped seats; and expansible means between two adjacent ends of the blocks of each pair to exert a pressure against such ends.

18. In an abrasive wheel, the combination of a body presenting a plurality of abutments each having an arc-shaped seat constituting a fulcrum; a plurality of abrasive blocks arranged in pairs, each pair being between two'seats and each block having an arc-shaped end seated in one of said arcshap'ed seats, the remaining pairs of ends of said blocks being arcshaped; and operating means between the remaining pairs of ends, said operating means including shoes having arc-shaped seats in which such remaining ends are seated.

19. In an abrasive wheel. the combination of a body presenting a plurality of abutmcnts each having an arc-shaped seat constituting a fulcrum; a plurality of abrasive blocks arranged in pairs, each pair being between two seats and each block having an arc-shaped end seated in one of said areshaped seats. the remaining pairs of ends of said blocks being arc-shaped; shoes having arc-shaped seats in which such remaining ends are seated, and means between said shoes to urge them apart.

20. In an abrasive wheel, the combination of a body presenting a plurality of abutments each having an arc-shaped seat constituting a fulcrum; a plurality of abrasive blocks arranged in pairs, each pair being between two seats and each block having an arc-shaped end seated in one of said areshaped seats; the remaining pairs of ends of said blocks being arc-shaped; shoes having arc-shaped seats in which such remaining ends are seated, and a wedge and wedge-operating screw between the shoes of each pair to urge them a art.

21. An abrasive element for use in a chuck of the class described comprising a block of abrasive material having two parallel fiat faces either of which constitutes a grinding face, two parallel cylindric surfaces whose common axis of generation is perpendicular to said fiat faces. and two non-parallel cylindric surfaces whose axes of generation are parallel with each other and perpendicular to said flat faces, said non-parallel cylindric surfaces being each tangent to both of said parallel cylindric surfaces.

22. An abrasive element for use in a chuck of the class described comprising a block of abrasive material having two parallel fiat faces either of which constitutes a grinding face, two parallel cylindric surfaces whose common axis of generation is perpendicular to said flat faces, and two non-parallel cylindric surfaces whose axes of generation are between such surfaces and are parallel with each other and perpendicular to said flat faces, said non-parallel cylindric surfaces being each tangent to both of said parallel cylindric surfaces.

23. An abrasive element for use in a chuck of the class described comprising an arcuate block of abrasive material having a fiat face which constitutes a grinding face, and two cylindric surfaces whose axes of generation (ill H ROLD F. SKILLINGS.

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