US2815615A - Honing device - Google Patents

Description

Dec. l0, 1957 J. sUNNEN 2,815,615

HONING DEVICE Filed Aug. 6, 1954 2 SheetS--Sheel' 2 V W//WWWW// United States Patent C) 2,815,615 HoNINGI DEVICE Joseph Sunnen, Clayton, Mo.

Application August 6, 1954, Serial No. 448,234

7 Claims. (Cl. 51-184.3)

This invention relates to improvements in expanding honing mandrels having radially adjustable abrasive elements and circumferentially spaced bearing shoes for maintaining constant pressure between the abrasive elements and the wall of the bore being honed.

One of the objects of the invention is to provide a honing mandrel which is particularly adapted vto honing bores which are interrupted by longitudinal keyways -or the like. To this end the abrasive element and the bearing shoes are provided with circumferentially divided, bore contacting areas which are circumferentially spaced so as to bridge keyway interruptions in a bore `and effectively avoid digging in at this point.

A further object is to provide a honing mandrel equipped with one or more bearing shoes, each having two circumferentially spaced bearing surfaces for contacting a bore and being rotatable on the mandrel about an axis parallel to the mandrel so as to permit self-alignment of the spaced bearing surfaces with the bore surface when the mandrel is placed in a bore.

A further object is to provide `a honing mandrel equipped with a radially adjustable stone holder carrying two circumferentially spaced stones which are associated so that each effectively supports the other as they successively traverse a keyway or like interruption in a bore.

Other features of the invention will appearhereinafter upon reference to the following specification and accom.

panying drawings, wherein like reference numerals desigf nate corresponding the drawings.

ln the drawings, Fig. l is a side 'elevation of a honing mandrel conparts throughout the several views of structed in yaccordance with the present invention, having parts shown in section; y Y

Fig. 2 is a side elevation of the mandrel when rotated 90 from the position shown in Fig. 1;

Fig. 3 is a side Velevation of the mandrel when rotated 180 from the position shown in Fig. l; p

Fig. 4 is an outer end view of the mandrel`taken on line 4-4 of Fig. 1; Y

Fig. 5 is a partial, longitudinal, sectional viewA taken on line 5-5 of Fig. 4; i v

Fig. 6 is a cross-sectional view taken online 6`6 .of

Fig. 1;

Fig. 7 is a side elevation of the stone adjusting wedge plate;

Fig. 8 is a bottom plan `view of the wedge plate shown fice Fig. 14 is an'enlarged end view of the bearing shoe shown in Figs. 12 and 13;

Fig. 15 is an enlarged end view of the bearing shoe clamps;

Fig. 16 is -a side elevation of the bearing shoe clamp;

Fig. 17 is a right end view of the bearing shoe clamp, and

Fig. 18 is a fragmentary sectional view taken through the underlying and overlying end portions respectively of the bearing shoe and bearing shoe clamp and is taken on line 18-18 of Fig. 3.

Referring to the drawings in more detail, numeral 10 designates a mandrel or arbor of cylindrical form having an inner shank end and an outer end portion which carries the abrasive elements and bearing shoes. The mandrel has a radial slot 12 milled therein extending throughout its length which slidably receives the guiding rib or stem portion 14a of a T-shaped radially adjustable stone holder 14, a wedge plate 16, and a stone adjusting wedge member 18. The outer end portion of the mandrel is also milled transversely so as to provide a wide Hatbottomed recess 20 which receives the wider, upper, horizontal, stone mounting portion 14b of the stone holder with the attached stones 22. Thewedge plate 16 lies in slot 12 alongside the` guide rib 14a of the stone holder and together they slidably tit the slot so as to maintain their alignment therein. The wedge plate 16 has a Hat upper surface which underlies the at under surface of the stone mounting portion 14b of Vthe stone holder and the wedge plate is detachably keyed thereto by a pin 23. Pin 23 is fixed in the wedge plate 16 and enters a hole 24 in the stone holder. A spring ring 25 tted in a groove in the pin 23 frictionally retains the pin 23 in the hole 24. The wedge plate 16 is spaced slightly from the under surface of stone holder portion 14b by a pair of spaced pads 26, one at each end of the underlying stone holder surface.

The under surface of the wedge plate 16 is formed with a pair of spaced, similarly inclined cam surfaces 28 which overlie and cooperate with upper spaced cam surfaces 30 formed on the upper surface of the underlying wedge member 18 so that, as wedge member 18 is moved longitudinally in slot 12, the stone holder and the stones will be moved radially.

The wedge member 18 extends substantially the full length of the mandrel and is provided at its other end with a transversely grooved attaching portion 32 which projects from the shank end of the mandrel for connection to suitable operating means for adjustably positioning it longitudinally in slot 12. Outwardly of the recess 20, the slot 12 is partially closed by a semicircular plate 34, which plate is press-fitted into a transverse slot in the ymandrel and forms an outward stop for the stone holder 14. Inwardly of recess 20, there is a block 36 positioned in slot 12 which jointly provides an inward stop for the stem portion 14a of the T-shaped stone holder 14 and a guide for the wedge member 18. The block 36, together with one wall and the bottom of slot 12, forms a closed channel in which wedge member 18 is guided horizontally and vertically. A screw 38 engaging threads partially formed in the block 36 and partially formed in the mandrel retains the block 36 in position. y

There is a slight space between one end of block 36 and the adjacent end of the stone holder in which is positioned a leaf spring element 40 which preferably is attached to block 36 and which yieldably urges the stone holder 1ongitudinally against the outer stop member 34. The stone holder is thereby frictionally held in the mandrel.

The stone mounting portion 14b of the stone holder is provided with a pair of at, outwardly facing, -stone mounting surfaces 14c which extend bilaterally from the guide rib portion 14A and which are oppositely beveled so as to conform to a degree with the outer surface of the mandrel. The two stones 22 are attached to these beveled surfaces by cementing thereto, or by any other suitable means, so as to present circumferentially spaced areas of contact with a bore being honed; The stone holder 14 with the stones 22 cemented thereon'is a replaceable tem which is replaced when the stones become too worn for further use. In the interest of economy, the stone holder is constructed of relatively soft metal adaptedto die casting so that the holders may be produced inexpensively. The wedge follower or wedge plate 16, which is interposed between the wedge member 18 and the under surface of the stone holder, is, however, constructed of hard, long wearing metal with precisely ground surfaces and forms apermanent element of the mandrel assembly.

The outer portion of the mandrel is further provided with a pair of longitudinally extending grooves or utes 44 which are spaced circumferentially from each other and from the slot 12 and recess 20. The grooves 44 are preferably true arcs in cross-sectional form and are of somewhat less than semicircular depth. Each of the grooves 44 receives therein an elongated bearing shoe 46 of genorally semi-cylindrical form having arcuate surface portions 48 engaging the groove which are of substantially the same radius as the groove and having an outwardly facing surface which is divided to form a pair of laterally spaced bearing surfaces 50 by the provision of a central longitudinally extending groove 52. These spaced bearing surfaces 50 project from the surface of the mandrel and are beveled as shown to conform generally with the surface of the mandrel. The contact area of the arcuate shoe surface with the groove is preferably reduced by cutting off a segment which results in the intermediate, flat portion 54 and the two laterally spaced arcuate portions 48. The shoes 46 are provided at both ends with short extensions 56, each having an arcuate groove 58 vformed therein, the surface of which is concentric with the arcuate surfaces 48 of the shoe, but having a considerably smaller radius than the arcuate surfaces 48. These bearing shoes are constructed of relatively soft metal such as a zinc alloy so they will not mar the surface of the bore being honed and so they may be economically produced by die casting. The shoes, being soft, are, of course, subject to appreciable wear and require replacement.

Each of the bearing shoes 46 is clamped in its groove 44 by a pair of shoe clamps 60, one at each end of the shoe. The clamps 60 are also lof general semi-cylindrical form with the edges of their flat side beveled, as at 62, in order to present an outer surface when assembled which more closely conforms to the curved surface of the mandrel. At one end the clamps 60 each have a short semicylindrical projection 64 of reduced radius which is preferably precisely the radius of the arcuate grooves 58 in the shoe extensions 56 into which they lit, as indicated in the enlarged detail view, Fig. 18. Near the same end of ythe clamp, a countersunk clearance hole 66 is provided which receives an attaching screw 68 for attaching the clamp to the mandrel. The curved surface of .the main body portion of the semi-cylindrical clamp 60 has a somewhat smaller radius than the bearing shoes or the grooves 44, but is provided with a semicircular collar or rib 70 which has a radius substantially equal to that of grooves 44.

It will be apparent from the foregoing,`that when a clamp 60 is placed in position in a groove 44 with its reduced projection 64 resting in the arcuate groove 58 of a shoe extension 56 and its collar portion 70 'near its other end bearing in the groove 44, its flat surfaces 62 will be in longitudinal alignment with the mandrel. It will also be clear that as the intermediately positioned screws 68 are tightened the bearing shoes will be effectively clamped in position, and that when screws 68 are loosened slightly, the shoes 46 can be rotated in the grooves 44. y

The inner end of the mandrel is provided with Va shank portion 72 which is eccentric with respect to the main body portion of the mandrel and has slidably fitted thereon for rotation an eccentrically bored sleeve member 74 adapted to be received in a chuck or collet on the driving spindle of a honing machine, similar, for example, to that shown in my Patent No. 2,638,721. The eccentricity of the sleeve bore with respect to its outer surface is substantially equal to the eccentricity of shank 72 with respect to the mandrel 10, so that when the sleeve is rotationally positioned on the shank, as illustrated in the several views of the drawings, its outside diameter is substantially concentric with the main body portion of mandrel 10, and the mandrel will, therefore, be concentric with the driving spindle. As the sleeve 74 is rotated on the shank from the position shown, its outer surface becomes progressively more eccentric with respect to the mandrel until it reaches maximum eccentricity at 180 of rotation.

Means is provided in the illustrated embodiment in the form of a pin 76 projecting from the shank 72 and a pair of diametrically opposed, cooperating notches 78 in the inner end of sleeve 74 for locking the sleeve either in a position of concentricity with the mandrel, as shown, or in the position of maximum eccentricity therewith. Obviously any number of notches 78 may be provided as desired for stepped incremental positioning of the mandrel shank in the sleeve. The sleeve is also preferably provided with a pair of diametrically opposed apertures 80 which provide access for shank engaging set screws carried in the collet of the machine and which act against the tapered portion of the shank so as toV retain the mandrel in the collet. To 'permit the sleeve 74 to be moved longitudinally sulicientlylto facilitate rotational indexing of slots 78 with the pin 76and yet retain ity on the shank, a spring retaining Yring r82 engaging an internal groove in the sleeve is provided, and the shank 76 has an intermediate reduced portion 84 forming shoulders which are engaged bythe ring' 82 to limit the longitudinal movement of the sleeve. The sleeve is further held frictionally in position on the mandrel shank against longitudinal shifting movement by a spring pressed ball element 86. There is als'o a pai'r' lof diametrically opposed notches 88 in the outer end of the sleeve 74 which are adapted to receive driving lugs on the honing machine chuck.

In s'e of the honing mandrel, the sleeve 74 is placed in the collet or chuck of a honing machine spindle with the sleeve notches 88 engaged by suitable driving lugs and the end of the c'am member 32 is connected to suitable feed adjusting means associated with the honing machine. The shoe clamp screws 68 are loosened slightly so as to permit rotational movement of the shoes 46 in their grooves 4 4 upon application of a moderate force to one or the other of their spaced surfaces 50. The mandrel is then inserted into a bore to be honed and the stone holder is then adjusted radially, by longitudinal adjustment of cam member y1 8, so that the stones 2 2 engage the bore surface. While maintaining a moderate, radially acting pressure between the stones and the bore by the feeding means, the mandrel is rotated slowly and tapped lightly to insure that the spaced surfaces 50 of the shoes uniformly engage the bore surface and that their contact areas andy those of the paired stones lie precisely in the same orbit. The mandrel is then removed from the bore, the clamp screws 68 are pulled up tight, and the honing mandrel is then ready for precision honing of the bore. By provision of the longitudinal groove 52, which divides the outer sho'e surface into the two laterally spaced surfaces 50, the circumferential scope of support of the wide shoe is maintained while establishing a minimum moment of rotation about the axis of rotation of the shoe so that the shoe will more readily andmore precisely align itself in a bore.

If the instant bore diameter is such as to require a radial adjustment of the stones which would result in objectional eccentricity of the orbit of the stones and shoes with respect to the mandrel and drive spindle centers for the particular honing operation, the sleeve 74 vis rotatably adjusted on the mandrel shank in a direction weight and character of the work piece, the means of supporting the work piece, and the honing speed would, of course, be determining as to what degree of eccentricity between the machine driving spindle "and orbit of the stones and shoes would result in objectionable whip of the work piece or adversely alfect the quality `of the work. When suitable adjustment of the sleeve has been made, the mandrel is suitably positioned in the collet with proper operative connection with the machine driving means, mandrel retaining means, and the cam feeding means.

Inasmuch as bearing shoes must be constructed of a material which is suiciently softer than the bore being honed, so as to avoid marring the bore surface, they are subject to wearing in conformity with the surface of the bore being honed. When a pair of circumferentially spaced bearing shoes having suicient width to effectively bridge bore interruptions, such as` keyways, has become worn in conformity with one bore diameter, the circumferential spacing and extent of their contact areas with a bore of larger or smaller diameter is altered. For example, if an expanding mandrel having a pair of spaced bearing shoes previously worn in conformity with a smaller bore diameter is expanded, by radial outward adjustment of its abrasive element, for use in honing a larger diameter bore, the worn shoes will contact the larger diameter bore at the adjacent edges of their surfaces, and if the mandrel is contracted for use in a smaller bore after the shoes have become worn in conformity with a larger bore, the worn shoes will contact the small bore at the remote edges of their surfaces.

This shift in circumferential spacing and this reduction in Contact area has two distinct adverse effects upon the quality of the work. First, the circumferential spacing of the shoe contact areas with respect to the abrasive element is varied from that which has been determined as optimum for opposing or backing the stone in order to elect uniform action of the stone on the bore surface. Obviously the wider the bearing shoe is made the more pronounced this variation becomes. Second, the circumferential extent of the contact area of the shoe is reduced, and if the change in sizes of the bores being honed is considerable, the shoe will Contact the bore substantially only at its edge. This condition, of course, renders the shoe ineifective to bridge interruptions such as keyways. Heretofore, the practice of shimming the bearing shoes has been used in order to maintain their alignment with the bore when the mandrel is expanded or contracted to accommodate the different sized bores. This practice is, however, time consuming and repeated checking with a master bore is usually necessary to accomplish the adjustment.

In applicants arrangement, however, wherein the semicircular shoes are mounted and retained for rotational adjustment in longitudinal arcuate grooves in the mandrel in the manner shown and described, a quick and simple means is provided for aligning the shoe contact faces with a bore so that the circumferential spacing of the shoe contact areas with relation to the stone element is substantially maintained and so that adequate contact area of the shoes is maintained `as the mandrel is expanded or contracted to accommodate bores of various diameter within its range of usefulness. The spacing of the paired shoe contact areas and the paired stone contact areas is preferably such that these paired areas of contact will at least successively support each other when traversing any width of keyway ordinarily required to be used in any bore within the range of usefulness of the mandrel.

When a single radially adjustable stone becomes worn in conformity with a smaller bore and is then adjusted radially to accommodate a larger bore, the circumferential extent of its contact withV thelarger-bore is diminished, and it approaches line contact with the bore as the larger bore diameter is increased. This condition would, of course, cause the stone, which is under outward radial pressure when in operation, to dig in when traversing any bore interruption of appreciable width, particularly one the size of a keyway. In order to solve this problem, applicant has provided a pair of closely asso'- ciated stones. It will be seen that with this arrangement, as in the case of the spaced shoe contacting surfaces 46, the minimum circumferential scope of support vcan never be less than the width of the spacing between the spaced stones, regardless of variation in bore size within the range in which the mandrel can be used. Under the worst condition, when expanding stones which have been worn to conform with the smallest diameter bore to the largest within the mandrel range, the reduced bore contacting areas of the stones, which will be near their adjacent edges, will successively support each other to bridge an interruption in the bore. The spacing and arrangement of the stones is such that under conditions involving the maximum expansion change of mandrel, the adjacent contacting surfaces of the stones will effectively support each other and bridge any keyway width ordinarily required to be used in bores within the range of the mandrel.

The foregoing detailed description and drawings are illustrative, the scope of my invention being set forth in the appended claims.

I claim:

l. A bore honing mandrel having a stone holder mounted for radial adjustment therein and a pair of soft metal bearing` shoes mounted thereon and circumferentially spaced from said stone holder and from each other, said bearing shoes being mounted for rotational adjustment on said mandrel about axes parallel to the mandrel axis, a pair of circumferentially spaced stones are mounted on said holder, each of said bearing shoes having a pair of circumferentially spaced bore contacting surfaces, and the Spacing of the paired stones and paired shoe surfaces being relatively small with relation to the circumferential spacing of the shoes and stone holder.

2. In a honing mandrel having a radially adjustable abrasive stone mounted therein, a pair of soft metal bearing shoes on said mandrel circumferentially spaced from said abrasive stone and from each other so as to support the abrasive stone when honing a bore, and said bearing shoes being adjustably mounted on said mandrel for rotation about axes parallel to the mandrel axis.

3. A honing mandrel having an eccentric shank portion at one end, an abrasive element mounted for radial adjustment in the main body portion of said mandrel, a pair of bearing shoes circumferentially spaced from said abrasive element and from each other and being adjustably mounted on said mandrel for rotational adjustment about an axis parallel with the mandrel axis, and .an eccentrically bored sleeve member mounted for rotational adjustment on said eccentric shank portion.

4. A honing mandrel having an eccentric shank portion at one end, an abrasive element mounted for radial adjustment in the main body portion of the mandrel, an eccentrically bored sleeve member mounted for rotational adjustment on said shank portion, means for locking said sleeve portion in adjusted position on said shank comprising a pin member projecting from the periphery of said shanlf` portion adapted to be received in any of a plurality of circumferentially spaced notches in one end of said sleeve member, and means for retaining the sleeve on said shank portion while permitting suicient longitudinal movement thereof to permit indexing of said pin in said end notches comprising an annular groove in said shank portion, and a removable spring ring retained in an annular groove in the bore of said sleeve and projecting into said annular groove in said shank member.

5. n 'ajhoning mandrel having a longitudinal groove ythereinof arcuate cross-sectional form, an elongated bear# ing 'shoe of general semi-cylindrical form mounted in said 'groove with its curved surface engaging said groove and'ha'ving an 'outwardly facing bearing surface, means for releasably clamping said shoe in said groove comprising a shoe clamp at' each end of said shoe and attached to 'saidrnandrel by screw means, each of said clamps having a convex arcuate surface which is concentric with and overlays a concave arcuate surface formed 'at each end of said shoe, whereby rotational adjustment of the shoe in the groove is permitted when the clamp attaching screw means is loosened slightly.

6. Inan expanding honing mandrel having a radially adjustable honing stone mounted therein, a pair of longitudinal grooves in said mandrel of arcuate cross-sectional form, a` soft metal bearing shoe in each of said grooves, Said shoes each having a convex Varcuate surface portion in contact with the surface of said grooves and an outwardly facing portion comprising a pair of circumferentially spaced contacting surfaces for engaging a bore to be honed, means for retaining said shoe in said groove whereby it may lbe rotationally adjusted therein or clamped in any ladjusted position, said means including a concave arcuate surface on said shoe which is concentric with its convex groove contacting surface, and la clamping element attached to said mandrel by screw threaded means, and said clamping element having a convex arcuate surface concentric with and in engagement with said concave shoe surface.

7. An expanding honing mandrel having an eccentric shaft portion, a stone holder mounted for radial adjust- 8 ment inthe main body 'portion of the mandrel 'and a pairo'f bearing" 'sh'oesrno'un'ted on the main body portion of lthe mandrel in circumferentially spaced relationship with said stone holder and with each other, said stone holder having'a pair of circumferentially spaced stones attached thereto, and said bearing shoes each having a pair of cirdumferentially spaced bore contacting surfaces, the spacing of said paired stones and said paired sh'o'e surfaces being relatively small with relation to the circumferential spacing of the Shoes and stone holder, said shoes being mounted foxrotational adjustment on said mandrel about an axis parallel with the mandrel axis, and an eccentrically bored sleeve member mounted for rotational adjustment on said eccentric shank portion.

References Cited in the le of this patent y UNITED STATES PATENTS 791,570

Newton June 6, 1905 864,463 Habel' Aug. 27, 1907 17,059,545 Kunze Apr. 22, 1913 1,109,321 Charles Sept. l, 1914 1,989,831 ISunnen Feb. 5, 1935 2,138,257 Sievers Nov. 29, 1938 2,537,286 Stovall Jan. 9, 1951 2,554,283` Wagstaff May 22, 1951 2,580,327 Sunnen Dec. 25, 1951 2,638,721 Sunnen May 19, 1953 2,639,394 Bentjens Sept. 21, 1954 FOREIGN PATENTS 869,911 Germany July 8, 1949

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