US2994993A - Roller construction - Google Patents

Description

Aug. 8, D. w JONES ROLLER CONSTRUCTION Filed Nov. 15, 1958 I ll l INVENTOR. DAVID W. JONES ATT'YS United States Patent 2,994,993 ROLLER CONSTRUCTION David W. Jones, Cavecreek, Ariz., assignor to Crane Packing Company, Morton Grove, 111., a corporation of Illinois Filed Nov. 13, 1958, Ser. No. 773,706 1 Claim. (Cl. 51-131) This invention relates to a roller construction and will be described for illustrative purposes with reference to its application to a roller exposed to gritty liquid on a lapping machine.

There has been proposed a type of lapping machine such as is disclosed in United States Patent No. 2,627,144 to R. G. Rushong wherein articles to be fiat lapped are placed within wear rings resting on a rotatable annular flat lapping plate. The wear rings are held against revolution with the lap by spaced rollers mounted on a bar fixed at one end to the machine frame and extending over the annular lap surface. When the machine is in operation, the lap plate rotates and induces rotation in the wear rings and in the articles in the rings, the rollers turning freely through contact with the exterior cylindrical surfaces of the rotating wear rings.

As part of the lapping operation in the above machine, a gritty liquid is caused to flow on the lap surface, preferably by directing the liquid over the outer surface of the ring down which it flows to the lap surface and is there spread evenly over the said surface by the relative rotation between the ring and lap. In its downward movement, the liquid traverses the surface contacted by the rollers and some of the liquid is thus transferred to the rollers from whence it finds its way into the bearings supporting the rollers from the arms. The presence of the gritty liquid in the bearing soon destroys the bearing and renders necessary a repair and replacement operation before the machine can be restored to operation.

An object of this invention is an improved roller construction wherein flow of gritty liquid into the bearing on which the roller turns is substantially eliminated and the life of the bearing is thereby greatly increased.

A more specific object of this invention is the provision of an improved roller construction wherein the side of the roller acts as a shield for the bearing thereof.

It has been found that the cylindrical surface of the roller which contacts the wear ring also Wears extremely rapidly and another specific object of this invention is the provision of a roller having a readily replaceable surface contacting the wear ring.

These and other objects of this invention will become apparent from the following detailed description of a preferred embodiment thereof when taken together with the accompanying drawings in which,

FIG. 1 is a plan view of a lapping machine provided with wear rings and equipped with roller means for holding the rings rotatively on the lap surface, said roller means being constructed in accordance with this invention;

FIG. 2 is an enlarged side elevational view in section of the roller of FIG. 1, the view taken along line 2-2 thereof and looking in the direction of the arrows at the ends of said line; and

FIG. 3 is an exploded view of the roller and associated mechanism.

Referring now to a detailed description of the preferred embodiment selected to illustrate this invention, the lapping machine environment which gives rise to the need for a roller of the type encompassed by this invention is shown in plan view in FIG. 1 and is comprised of a frame which supports an annular lap plate 11 for rotation about a vertical axis. Adjacent lap plate 11 and fixed to frame 10 is a container 12 having suitable means therein 2,994,993 Patented Aug. 8, 1961 (not shown) for agitating a gritty lapping fluid. Valve means, shown only in outline at 13, may be used to meter and control the flow of fluid from container 12 along a wire 14, the free end of which extends over the surface of lap plate 11.

Resting upon lap plate 11 are two wear rings 15 and 16 extending across the lap 11, the function of which is to dress the lap while articles are being lapped thereon. Said rings are held against revolution with the lapping surface by a pair of arms 17, 18 mounted on fixed posts 19 (FIG. 2) and secured thereto by hand nuts 20 and 21. The arms 17 and 18 have mounted thereon spaced rollers 22, 23 and 24, 25 which engage the side cylindrical surfaces 26 and 27' of the wear rings 15, 16 so that said rings may rotate freely between their respective pairs of rollers.

Work to be lapped (not shown) may be inserted into the wear rings so that said wear rings function not only to condition the lap surface, but also to hold the work being lapped.

When in operation, lap 11 is rotated by any suitable means (not shown) and the frictional forces developed between the surface of lap 11 and fiat sides of the wear rings 15 and 16 resting thereon induces a rotation in the wear rings in the same direction and at substantially the same speed as lap plate 11. This rotation causes the wear rings to sweep across the surface of the lap plate 111 to perform their conditioning action and in addition to assist in spreading the lapping compound evenly over the lap surface. As shown more clearly in FIG. 2, the underside of each wear ring has a series of slots 28 extending from the exterior of the ring to its interior to promote the flow of the lapping compound to the interior of the rings where it is utilized to abrade the work, In some instances, to insure the even spreading of the lapping compound over the lap surface, the end of Wire 14- along which the compound flows is made to bear directly against the side 26 of a ring. It is obvious under these conditions that the lapping compound will come in contact with the rollers 22, 23 and unless the supports therefor are properly shielded from the compound, where relative movement occurs between the roller and support, the contacting surfaces will likewise be lapped and soon destroyed.

A pivoted roller support made according to this invention is shown in FIGS. 2 and 3 as applied for example to roller 23 and is designed particularly to shield the roller bearing thereof against the entry thereinto of the lapping compound.

Referring particularly to FIGS. 2 and 3, the roller 23 is shown mounted on a pin 29, the lower end 3% of which is threaded and received in an appropriately threaded opening 31 disposed in the end region of arm 17. A shoulder 32 on pin 29 located at the end of the threaded portion 30 of the pin limits movement of the threaded end into opening 31 and allows pin 29 to be tightened into the opening to prevent inadvertent release of the pin and its associated roller 23. For small rollers a screw driver slot 33 may be provided in the lower end of pin 29 by which said pin may be manipulated. It is understood that arm 17 is removable from its support so that pin 29 may be assembled with respect thereto before the arm is assembled on its support.

Roller 23 in the form chosen to illustrate this invention is not provided with a central through opening but instead is formed with a recess 34 of cylindrical form and concentrically disposed with respect to the exterior cylindrical surface 35 of the roller. Said recess is reduced in diameter at 36 to provide a shoulder 37 for locating the outer race 38 of an antifriction bearing 39. A snap ring 40 holds the outer race 38 from axial movement out of recess 34.

Inner race 41 of antifriction hearing 39 is mounted on the reduced end 42 of pin 29 and is located against the shoulder 43 formed at the lower end of said reduced diameter portion 4-2. Movement of inner race 41 upwardly as viewed in FIG. 2 ofi the reduced diameter portion 4-2 is prevented by a snap ring 44.

It may be observed that roller 23, having a continuous and unbroken wall extending over its upper end as viewed in FIG. 2, provides no access for lapping compound to the recess 34 by gravity flow. Any tendency for lapping compound to work its Way upwardly from the bottom surface 45 of roller 23 is minimized by the centrifugal force acting upon the compound while the roller is rotating. This centrifugal force tends to fling the compound radially outwardly instead of encouraging or allowing the compound to move radially inwardly into recess 34. It may be noted that roller 23 extends below bearing 39 and its races 38 and 41. If perchance some compound should find its way into the lower region of recess 34, movement upward into the bearing 39 is discouraged by gravity acting to draw the compound downwardly out of the recess.

It thus is readily apparent that the construction of roller 23 illustrated in FIG. 2 effectively prevents the entry of lapping compound and other deleterious substances into the bearing and thus prevents undue wear thereof and the impairment of its function.

Obviously, contact between the exterior surface of roller 23 and the exterior surface 26 of the Wear ring cannot be avoided. Complete destruction of the roller 23 from the exterior thereof may be prevented, however, by using a removable and replaceable surface material on the roller in accordance with this invention.

Referring again to FIGS. 2 and 3, roller 23 has a wide groove 46 formed in the outer cylindrical surface thereof into which are placed enough endless rings 47 of resilient elastomeric material to fill the axial dimension of the groove. Said rings 47 may take a form of commercially available O-rings which are relatively inexpensive and readily obtainable in a large variety of sizes and rubberlike materials. The rings 47 are readily stretched over the ends of the roller into the groove, the rings additionally being of such initial diameter as to be slightly stretched when they are in place in the groove.

It is understood that the foregoing description is merely illustrative of a preferred embodiment of the invention and that the scope thereof is not to be limited thereto but is to be determined by the appended claim.

I claim.

A roller assembly for laterally supporting the cylindrical wear ring of a lapping machine, said roller assembly comprising a fixed pin, anti-friction bearing means mounted on the pin, a roller mounted on the anti-friction bearing means, said roller having a wide exterior peripheral groove formed thereon, said groove having a cylindrical bottom face, and a plurality of identical resilient elastorneric 0 rings arranged in side-by-side relation in said groove and filling said groove, said 0 rings having an internal diameter smaller than the diameter of the bottom of the groove before being stretched over the bottom of the groove and an external diameter greater than the diameter of the roller, whereby said 0 rings are retained frictionally against rotation in the groove, and whereby said 0 rings form the wear ring contacting surface for the assembly.

References Qited in the file of this patent UNITED STATES PATENTS 277,154 Osborne May 8, 1883 732,728 Forsyth July 7, 1903 2,079,076 Kranich May 4, 1937 2,264,598 Stainbrook Dec. 2, 1941 2,627,144 Roshong Feb. 3, 1953 2,660,840 Bergstrom Dec. 1, 1953 2,777,330 Barclay Jan. 15, 1957 2,839,877 Boetteher June 24, 1958

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