US2467094A - Abrasive article - Google Patents

Description

April '12, 1949.- D, T, PEDEN 2,467,094

ABRAs IVE ARTICLE Filed Jan. 28, 1949 INVEN TOR. Zalig/d5 T 77Je/r,

BY 'EE E. M2@ Vf@ Patented Apr. 12, 1949 UNITED STATES TENT FFICE ABRASIVE ARTICLE Application January 28, 1949, Serial No. 73,416

Claims.

This invention relates to improvements in abrasive articles, and more particularly to honing stones for producing accurate and finely nished surfaces, and is a continuation-impart of Serial No. 499,472, led August 21, 1943, and assigned to the assignee of the present invention.

While the invention is broadly applicable to the regulation of Wear of such abrasives, it is more directly concerned with its use as a means for eicently gauging the size of a workpiece during the operation of this type of honing stone thereon.

The primary object of the invention is to afford. a practical adjunct to the method of gauging oi the type disclosed in U. S. Patent No. 2,398,356, issued January 12, 1943, which was assigned to the assignee of the present invention. It is, nevertheless, to be understood that the invention is not to be restricted to such use as is evident from the objects of the present invention which are: to provide nonabrasive portions on a honing abrasive of a character which will wear consistent the wear of the abrasive and be suitable for contacting a gauging means without the latter; to retard the rate of break-down or wear of the abrasive under circumstances of extreme pressure application, from whatever source, without interfering with its normal wear rate; to afford stability to abrading members, particularly those of relatively small working area, when they are in contact with the workpiece; to augment the tensile strength of abrading members so as to avoid their shattering under vibration or chattering conditions of operation, and to provide an economical and practical means for mounting hone abrasives and prolong their service life.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawing, in which:

Figure 1 is a perspective view of a honing abrasive embodying features of this invention;

Fig. 2 is a sectional view of the structure illustrated in Fig. 1, taken on the line 2-2 thereof;

Fig. 3 is a view of structure, similar to that illustrated in Fig. 1, showing another form of the invention;

Fig. 4 is a sectional view of the structure illustrated in Fig. 3, taken on the line t-ll thereof Fig. 5 is a view in elevation of a tool and abrasive elements employed in conjunction with a gauge member which indicates the moment the cylinder has been machined to size;

Fig. 6 is a sectional View of a short abrasive stone and supporting element by which it is applied to a workpiece; and

Fig. '7 is a perspective View of a tool with the honing abrasives illustrated in Figs. 3 and 4 disposed therein.

In the aforementioned U. S. Patent No. 2,308,- 356, titled Gauging method and means, a calipering or measuring device is disclosed which directly measures the size of the tool during its operation on a workpiece. This also a measure of the bore which could be finished to any desired dimension. The abrading members of the honing tool were arranged to directly contact the gauging means at an extremity of the working stroke and indicated when the diameter had .been reached. It was found that a slight abrading effect resulted, occurring as a result of the contact of the gauging elements with the abrading material, which necessitated occasional readjustment of the gauging mechanism to compensate therefor.

The present invention obviates the need for the readjustments of the gauging mechanism by virtue of providing nonabrading tabs at the extremities of the abrasive. As illustrated in Fig. 1, this may be accomplished by applying non-abrading inserts at the ends of the abrasive elements 2. The inserts l may be composed of phenol or vinyl resinous material, hard rubber, vulcanized ber, soapstone, sodium silicate, carbon or certain porous metals such as magnesium, aluminum, etc. In fact, any organic or inorganic material which possesses the ability to wear with the abrasive, and yet resist impregnation or loading with abrasive particles, may serve as such inserts. The abrasive elements 2 and the nonabrading inserts l are adhesively mounted in a metallic backing element 3. Turned-up lugs t may be provided at the ends of the element 3 to assist the adhesive to resist the endwise thrust occurring to the element and inserts during operation. Projections 5 extend beyond the lugs d. ,for forming a convenient means for receiving a circular garter spring or spring clips which urge the stones inwardly when the honing tool is contracted. In Fig. 2, the element 3 is illustrated as being provided with bosses 6 to prevent endwise movement of the abrasive assembly when it is mounted in the stoneholder of the honing tool. The bosses mate with apertures in the stone-receiving groove of the stoneholder and prevent relative movement therebetween.

In Fig. 3, the ve surfaces of the abrasive element 'l are encased in the nonabrading material 8 which forms the nonabrasive engaging portion of the stone assembly having the extended ends 9; The encasing material protects the sides of the ing inserts l.

vtween the inserts l and element i3.

`possessing interruptions, such `tl'iesurtace to be honed, as ustrated i -Un'dersuch circumstances, it is impractical, for Vreas-ons of the inaccuracies engenderedyto use invention makes possible the use ci abr stone from fracture due to chatter or overloading. This type of assembly may be mounted in a stoneholder or be inserted directly in the hone body 3| in direct contact with an expansion cone 32, as illustrated in Fig. 7. The expansion cone 32 is provided with a plurality of grooves 32a each adapted to receive one of the encased stones, the bottomwall 32b of each of the grooves'tila being inclined relative to the axis of the cone .t2 so that the stones can be radially adjusted by longitudinal movement of the cone 32 relative to the hone body 3|. In this construction, the retaining y(ir-garter springs are not required as the frictional contact between walls 33 of the tool `bodyfslots and the nonabrading material constituting "the casing S is sufficient to retain the abrasive assemblies within the hone body 3 l.

In Fig. 5, a gauging device is illustrated in con junction with a honing tool having the abrasive elements oi Figs. l and 2 applied thereto. A supporting lbracket lll retains aslee'vel i'aligned with honing tool l2 which is reoiprocated therethrough. caliperlile gauging element has Guide elements of fibre or other the abrasive elements Hl. These guide the tool `body in the bore l being machined the ap'erture'll in the sleeve il. A garter spring i3 is employed at the bottom of *be tool body l2 engagement with the projections While individual springs it engage the projections at the upper endsof theabrasive elements lil.

Each time the honing tool l?. has stroked to the upper Yextremuzy oi its'travel, Contact made 'bei3 and the nonabrad- When the desired Wort: .dse has been achieved on the abrasive elements tl, the switch 2l will be operated by the next contact bevinasmuch `as the nonabrading tabs have contacted the worktveen the auffinCT element g D D .piece immediately prior to this instant andfhave worn to the same height as thato the abrasive `unstable against thrust loading despite any mechanical counter means whichmay be provided. This condition is also encountered in worlpiecos s ports or ots, in

abrasive elements of suicient length to` span the interrupt-ion 23 in the workpiece itil. The present ve elements suiciently short to secure the accuracy' desired on work surfaces 25 and still obtain lthe sta bility andspanning abili-tyaiiorded by long abrasive. This is accomplis-lied by making abrasive element 2&3 of the most effectual Vlength and :augmenting its length with nonabrading body portion 2l which is ci sufficient length to restore stability against the element E6 tilting "when force `is axially applied Vto the'honing tool when under vpressure produced by the movement of the spaced cones 28.

The typeof nona-bradi-ng material chosen is predicated upon the character of the abrasive used. For example, hard bonded abrasives may require an insert, or be encased in, a high Wear resistant material such as vinyl resin or aluminum. A soft bonded abrasive would respond better if phenol resin or magnesium were used therewith. In any case, it is important that the wear resistance of vhe insert or encasing materialbe not greater than that of the abrasive ii efficient results yare to be obtained.

While the phenol and vinyl resins have satisfactory wearing qualities with relation to the wearing qualities of the abrasive stones, as pointed outabove, vthey fare slightly resilient and the substantial pressure applied to the abrasive units the expansion-'cone 32 during a honing operation `causes the phenol and vinyl materials to slightly compress. As a result, upon the release of the pressure when the cone 32 is retracted, the sides and the end portions l and 9 of the units expand and project slightly :beyond the 'face of .e stones 'l and serve tolprotect thenished honed surface from accident and 'undesirable marring by the stones upon the continuedrotation of the tool as it being withdrawn from :the honed cylinder. This minute expansion of the l at the ends oi the abrasive stonesgis 'not detrimental to the gaugingol the borefupon'fthe operation of th `ggf-inging mechanism by the'ends i and t as this slight expansion either is within the degree oi accuracy or" the diameter tolerance permissible or the amount of expansion,=being a constant factor, can be `allowed tordu-setting the gauging mechanism to interrupt .the honing'operation when esired size is reached. This slight resiliency of the phenol and vinyl resinsifaid eubstar y in the retention-oi the -abrasiveelements in the slots when the pressure is removed from the elements, and thefmaterialsprovide a noninarring bearing engagement With the-slot Walls when moved relative thereto.

What is claimed is:

l.. A honing element fora honing tool having a body containing slots for the reception of a plurality' of said elements and an adjusting-member for radially moving said elements outwardly of said body and applying a pressure thereto, said element embodying a bonded abrasive stick of substantial length relative .to its'width and thickness, and a casing of a relativelynon-abrasive material covering said abrasive stick on 4'all surfaces except its working face, said casing being of substantially greater lengththan said abrasive stick to provide a longitudinally extending tab :at each end of said abrasive stick, each of said tabs having va surface substantiallyin theplane'offthe working face of said abrasive stick and being of such character as to wear uniformly with'the abrasive stick while providing such frictionalvengagement with the wallsof the slots in the tool body, Without abrasion of the slot Walls, as to frictionally retain the elements'onthe tool body and within the slots but permittlng'them to be moved outwardly by the application of a positive force by the adjusting member.

2. A honing element for a honing tool having a body'containing slots for the reception of a plurality of said elements andan adjustingmember for radially moving said elementsfoutwardly of said body and applying a pressure'thereto, said element embodying a ibon'de'd abrasive-:stick of substantial length relative. toits Width .and thickness, anda casing of a relatively rnonabrasive =ma terial covering said abrasive stickfzon'all surfaces except its working face, the vmaterial @of Asaid casing being compressible to a greater degree than said abrasive stick under a given load, said casing being of substantially greater length than said stick to provide a longitudinally extending tab at each end of said stick, each of said tabs having a surface substantially in the plane of the working face of said abrasive stick and being of such character as to wear uniformly with the abrasive stick while providing such frictional engagement with the walls of the slots in the tool body, without abrasion of the slot walls, as to retain the elements on the tool body and within the slots but permitting them to be moved outwardly by the application of a positive force by the adjusting member, the compressibility of said longitudinally extending tabs enabling the same to project a minute amount beyond the working face of the abrasive sticks for preventing the honed iinished surface from being marred by the abrasive sticks when the abrading pressure is removed therefrom and the tool is being withdrawn from a honed cylinder.

3. A honing element for a honing tool having a body containing slots for the reception of a plurality of said elements and an adjusting member for radially moving said elements outwardly of said body and applying a pressure thereto, said element embodying a substantially rectangular bonded abrasive stick of a length greater than its width, `and a casing of a relatively nonabrasive material adhered to said abrasive stick and covering all of the surfaces thereof except its working face, said casing being of substantially greater length than said abrasive stick to provide a longitudinally extending nonabrading tab at one end of the abrasive stick, said tab having a surface disposed substantially in the plane of the working -f-ace of said abrasive stick, said nonabrasive material being of such character as to wear uni formly with the abrasive stick and to provide frictional engagement with the walls of the slots so as to be frictionally retained in the tool body while permitting movement thereof outwardly when a positive pressure is applied to the elements by the adjusting member, said tabs providing for nonabrading engagement with a diameter measuring device as the abrasive sticks are adjusted outwardly of the tool body to a desired diameter.

4. A honing element for a honing tool comprising a bonded abrasive stick of substantial length relative to its width and thickness, and a casing of a relatively nonabrasive resinous material covering said abrasive stick on all of its sides except its working face, said casing being of substantially greater length than said abrasive stick to provide a longitudinally extending tab at ea-ch end of said abrasive stick, each of said tabs having a surface lying substantially in the plane of the working face of said abrasive stick.

5. A honing element for a honing tool comprising a bonded abrasivel stick of substantial length relative to its width and thickness, and a longitudinally extending member at each end of the stick having a face disposed substantially in the plane of the working face of the abrasive stick, said member being formed of a resinous material having the property of wearing substantially at the same rate as the abrasive stick and being slightly compressible radially under load so that the said face of each member extends a minute amount beyond the working face of the abrasive stick when the load is released from the element after a honing operation for preventing the working face of the abrasive stick from contacting the finished surface of a honed cylinder when the tool is withdrawn therefrom.

DOUGLAS T. PEDEN.

REFERENCES CITED The following references are of record in the lile of this patent:

l UNITED STATES PATENTS Number Name Date 1,392,426 MacDonald Oct. 4, 1921 1,781,856 Moser Nov. 18, 1930 1,372,567 Bryant Aug. 23, 1932 2,106,205 Conner Jan. 25, 1938 2,256,495 Rioux Sept. 23, 1941 FOREIGN PATENTS Number Country Date 36,972 Netherlands Dec. 16, 1935 543,293 Great Britain Feb. 18, 1942

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