US2110086A - Abrasive wheel and mount therefor - Google Patents

Description

2 Sheets-Sheet 1 H. S. INDGE Filed June'25, 1935 mm 9n ABRASIVE WHEEL AND MOUNT THEREFOR H/ M K J I March 1, 1938.

INVENTOR HERBERT 51MB GE A T ToRNEY WITNESS mzzh Margh l, v1938. I s, [NDGE 2,110,086

I ABRASIVE WHEEL AND MOUNT THEREFOR Filed June' 25, 1935 2 Sheets-Sheet :2

I INVENTOR Wrnwss5 HERBERT 5. I GE ,JM M 542M ATTORNEY Patented Mar. 1, 1938 Q PATENT OFFICE ABRASIVE'WHEEL AND MOUNT THEREFOR.

- nerberts. Indge, Westboro, Mass, assignor to Norton Company, Worcester, Mass., a corpora ton of Massachusetts Application June 25,

2 Claims.

This invention relates to abradant wheels and apparatus for mounting them.

One object of the invention is to'provide an abradant wheel of relatively large peripheral surface area. Another object of the invention is to provide a conical abradant wheel of relatively great length with relation to its average diameter. Another, object of the invention is to provide a wheel mounting and wheel construction of frusto-conical formwhich shall reduce wheel wastage. Another object of the invention is to provide a wheel construction of interchangeable sections. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

, In the accompanying drawings; in which is disclosed one of many possible embodiments of the mechanical features of the invention,

Figure 1 is a view of a portion of a continuous lapping machine illustrating a pair of abradant wheels and mounting apparatus therefor applied thereto, one wheel being shown in axial section and the other in front elevation;

Figure 2 is a vertical sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a vertical sectional view taken on the line 3-3 of Figure 1. V

This invention is in part disclosed in my copending application Serial No. 5,271, filed February 6, 1935, now Patent No. 2,087,874, dated July 20, 1937, relating to lapping machines. In that application I have disclosed a lapping machine having a pair of frusto-conical lapping wheels adapted to finish a cylindrical work-piece which i is maintained between the wheels by guides, the work-piece being fed through the machine by skewing one or both of the wheels. The aforet said copending application further discloses an apparatus for shaping the originally frusto-conical wheels so that, despite the fact that they are skewed, they will effectively lap a true cylindrical work-piece. Such shaping modifies the peripheralsurface of each wheel by producing therein a slight concavity. The dressing apparatus disclosed in the copendingapplication will not be described in detail herein particularly insomuch as, so far as the present invention is concerned,

, any substitute might be employed; nevertheless,

for a clearerunderstanding of the shapes of the wheels according to the present invention, it is 1935, Serial No. 28,236 (01. 51-103) noted that the dressing device is mounted for traverse between the wheels in a rectilinear path, and, insomuch, as herein described, the wheels are mounted for angular adjustment on an axis at right angles to their axis of rotation, dressing or truing of the wheels with such dressing device may produce a concave contour therein if they are skewed with respect to such rectilinear path. Insomuch as I rely for the production of certain efiects in lapping upon moving abrasive material at an angle to the axis of the work-piece, which is not a right angle, I skew the axes of the wheel spindles with respect to the saidrectilinear path and dress the wheels to produce such concave surface which generates a true cylindrical surface or leaves a true cylindrical surface on the workpiece. So faras certain claims are concerned, therefore, each wheel and each wheel section herein described may be considered to have a slight concavity in its peripheral surface; insomuch as ordinarily such concavity is of a slight degree, it has not been illustrated in the drawings, and insomuch as, further, the degree of concavity is a variable depending upon setting of the wheels and the particular type or work-piece being lapped. The present application is directed to the construction and mounting of the wheels per se. In the manufacture of abrasive wheels there are and have been certain practical limits on the size thereof both in an absolute sense and relatively with respect to the ratio of thickness to diameter. Whatever might be regarded as the limit in either of these respects, it is notthat a larger wheel or a thicker wheel could not be made, but that it is not convenient and economical to do so. In the case of large wheels and wheels which are extremely thick with respect to their diameters, a disproportionate number might have to be rejected because of the development of cracks in the firing or baking or other heat treatment or otherwise; such wheels, however made, are difiicult to handle while in process of. manufacture, a so-called green wheel (an This plate II has a milled or planed horizontal upper surface 1-! 2jupon which rests a table l3. A

trunnion'l4 having a vertical axis extends downwardly from the under side of the table I3 and fits in a, bore IS in the supporting plate II, and

thus the table I3 is restrained against any hori- The table I3 supports anabrasive wheel and spindle to be described, and a similar wheel is mounted above it. Considering now the support for the upper wheel, the machine of the copending application referred to has a column attached to thebase H), which column is not shown herein as, so far as the features of this invention are concerned, it may be of any desired form, and mounted on the column is a slide adjustable in a vertical direction, on the column, the slide beinglikewise not shown herein, and extending forwardly from the slide is an overhanging support 20 which may be integral with the slide; thus in a sense the casting 20 shown in the drawings is part of said slide. On the under side of the overhanging support or over-arm 20 is a large flat plane surface 2| extending approximately over the horizontal upper surface l2 of the supporting plate ll. Held against this surface 2| is a table 22, and a trunnion 23 fitting in a bore 24. mounts the table 22 for angular adjustment. The table 22 is prevented from falling and is held against the surface 2| by means of cooperating segmental guiding surfaces 25 and 26. The trunnion 23 may be provided with radial supporting plates 21 to assist in supporting the load. The upper and lower abrading wheels 30 and 30a respectively are, atvleast initially in this embodiment of the invention, frusto cones, and they and the journaling means for them and their mounting upon their spindles being similar, I have Shown only the upper wheel 30 in cross-section and it should be understood that the journaling means and spindle supports for the lower wheel 30a is simi lar to, that for the upper wheel 30. It will also be noted from inspection of the drawings that the frusto- conical wheels 30 and 30a. are oppositely disposed and the locus of the abrading throat is between the wheels, the work guides not being shown herein.

Still referring to Figure 1, extending downwardly from the table 22 and desirably integral with his a head 3|. Likewise a head 3la extends upwardly from the table l3. Each head is hollow as shown in the case of the head 3|, and formed on the inside thereof is a roller bear-, ing race recess 32. The "outer race 33 of a roller bearing seats in the recess 32 while the inner race 34 seats on-a cylindrical portion 35 pro-.

vided on a spindle 3G. Conical rollers 3'll are shown located between the races 33 and 34.

, The inner race 34 is held on the spindle 36 by means of a shoulder 38 .on the spindle at one side of the race 34, and a sleeve 39 on the other sidethereof. The thrust on the sleeve 39 is taken by an inner race 40 of a. second roller bearing which is mounted on a cylindrical portion 4| of the spindle 36 and which also abuts a square shoulder 42 on the spindle. Conical rollers 43 are located between the inner race 40 and an outer race 44 which is seated in a recess 45 provided in an annular member 46 which is secured in the head 3| fitting in'a cylindrical bore 41 thereof. The annular member 46 has a circular recess 48 for the reception of a cap 49 which keeps grit out of the bearings and oil or grease therein if desired. In order to take the thrust on the inner race 40 and to position bothraces 40 and 34 upon the spindle 36, the spindle 36 is threaded at 50 and a couple of nuts 5| and 52 are placed on the portion 50, the inner nut 52 beingin contact with the race 40. Thuswhen the nuts. are tightened thrust is exerted from theinner nut 52'to the race 40, from there to the sleeve 39 to the inner race 34 and against the shoulder 39. Insornuch as the outer races 33 and 44' are held between the recesses 32 and 45, the bearing means described constitutes an anti-frict'ion radial and, thrust bearing for the left-hand end of the spindle 36, there being a similar bearing in the head 3la for the similar spindle 36a.

The spindle 36 may be driven from inside the head 3|. Keyed to the sleeve 39 is a worm wheel 55 which is driven by a Worm 56 on a shaft 51 whose axis is at right angles to that of the spindle 36. The worm wheel 55 extends through a cutout 58 in a sleeve 59, and for the remaining features of the driving mechanism I will now refer to the similar construction in connection with the head 3 la, as illustrated in the cross-sectional view of Figure 3. The spindle 36a has keyed thereto a sleeve 39a to which is keyed a worm wheel 55a' which is driven by a worm 56a keyed to a shaft 51a. There is a. cutout 58a in a sleeve 59a which has a flange portion 60a that is bolted to the head 3la by bolts 610., there being a shoulder 62a which fits in a bore 63a in the head 3la. Thus the sleeve 59a is held in a fixed position in the head 3Ia, and the other end of the sleeve 59a fits in a bore 64a in the other side of the head Ma.

The worm 56a abuts a shoulder 65a on the shaft 51a, this shoulder receiving the driving thrust. The other end of the worm 56a abuts a sleeve 66a on the shaft 51a. The shaft 51a has a reduced portion 61a which is threaded at the end. A lock nut 68a holds an inner race 69a of a ballbearing on the reduced portion 61a, but a slight clearance is provided, as shown. The thrust on the shaft 51a is taken by the bearings of a driving motor Illa but when the motor is slowing down, or when the thrust on the worm 56a is reversed for any reason, the slight left-hand thrust of the worm 56a. is taken by thesleeve 66a, transmitted to the inner race 69a, and taken by bearing balls Ila and thus transmitted to an outer race 12a. and thence to a bearing cap 13a. The outer race 12a is positioned in a recess-14a in the sleeve 59a and held therein by a shoulder 15a or the bearing cap 13a. The bearing cap may be held in position by bolts 16a. Thus the ball bearing consisting of races 69a, 12d and balls Ila is essentially a radial bearing,

The other end of the shaft 510. passes through a stufling box 30a that is bolted by bolts 8la to the sleeve 59a, the stufiing box having a head motor 10a through a coupling 90a. The motor 10a is'moun'tedon a platform 9Ia which is integral with an extension 92a of the table I3. Thus the drive is not interfered with by adjustments in angular position of the wheel 30a.

Considering again the upper spindle 36, the

"mechanism for driving it is similar to that al- 'shown'in the copending application referred to.

ready described, although .a different means of allowing for adjustments in the angular position of the wheel 30 may be provided, for example as In order to seal oil or grease in the roller bearings described and to keep grit therefrom, packing I 95 and a gland 96 may be provided. The gland 96 consists of nearly over-lapping annular portions on the outside of the head 3| and on a flange portion 91 of a hollow spindle or sleeve 99 which is connected to the driving and supporting spin-- dle 36 by a spline connection I00.

Still considering the upper part of Figure 1, upon the hollow spindle99 I mount a plurality of abrasive wheels IOI, I02, I03, I04, I05, I06, I01 and I08. Each of these is a frusto-cone with an axial bore just fitting the outside of the hollow spindle 99. The small end of the wheel IOI has a diameter-just equal to that of the large end of the wheel I02, and all the others down to the end wheel I08 have diameters equal to that of the large ends of the adjacent wheels respec- I tively. Preferably each wheel is of the same thickness as allthe others. While this invention contemplates the use of any kind of wheel so far as composition is concerned, I have achieved excellent results in a. lapping machine using fine grain silicon carbide ina shellac bond. Other grain may be used, as alumina, emery, corundum, garnet, quartz, and other bonds, as ceramic, rubber, synthetic resins, sodium silicate.

In the assembly of the entire wheel 30, the component wheels I to I08 are slipped onto the spindle 99 in the order described and shown, and with the wheel IOI against the flange 9'I. Desirably the sides of each wheel excepting the large Gil side of the wheel IM and the small side of the wheel I 08 are coated with a suitable cement, such as, in the case of shellac bonded wheels, a coating of shellac. A washer I09 and a nut IIO fltting on a threaded portion III of the spindle 99 secure the individual wheels together as a unit and compress the cement so that it will set. Before explaining the features of the wheel 30 further, I shall complete the description of the mounting means.

Still referring to the upper part of Figure 1, the spindle 36 adjacent the right hand end of the outer hollow spindle 99 has a threaded portion II2 on which is located a nut II3 which clamps the spindle 99 against a shoulder I on the spindle 36 adjacent the flange 91. At the right-hand end of the spindle 36 is a reduced cylindrical portion I-I5. Referring now to the upper righthand part and also to the lower left-hand part of Figure 1, and also to Figure 2, the table I3 has attached to it ways II6a and the table 22 portion I I of which is supported and j'ournaled in the head I".

Considering now the journals for the outer ends of the inner spindles, and referring to the upper right-hand part of Figure 1 and also to Figure 2, a cylindrical recess I 20 is formed in the head I", which recess is open at the righthand end and has a shoulder I2I and an annular flange I22 at the left-hand end. An outer casing member I23 'flts in the recess I20 against the shoulder I2I and thismember I23 has on either side thereof annular plates I24. An outer race I25 fits between these three last mentioned parts between which outer race I25 and an inner race I26 are-located cylindrical rolls I21. The inner race I26 is press-fitted upon a sleeve I20 which removably flts the reduced portion 5. There is a clearance between the annular plates I24 and the sleeve I28 while a nut I29 maintains the assembly of the anti-friction bearing when it is slid off the reduced portion H5. A hearing cap I30 fitting in the recess I20 together with the annular flange I22 seals the bearing for retention of oil or grease and the exclusion of grit, while'it is noted that'the flange I 22 is just clear of the sleeve I28.

By reason of the construction described, the head .I-II may be slid off theend of the spindle 36 at any time. The bearing just described is a radial bearing and takes no thrust, and preferably the heads I I1 and I IIa are not clamped upon the ways H6, H8 and 611, Had, thus permitting the parts to find their natural position with- The bearings including the rollers B'I and 43 are built to withstand the strain of the weight of spindles and wheels without any outer support, as these hearings are double radial and thrust bearings spaced a substantial distance apart. Consequently it is a simple matter to place the wheels IOI to I08 or IOIa to I08a upon the spindle 99 or 99a and secure them in place with the washer I09 and nut H0 or washer I09a and nut Ba. 7

The wheels having been assembled, the machine may be used as described in the copending application referred to. As the machine is used, the. wheels-will be dressed and trued from time to time to take care of wheel wear and ad justments. Each different position of skew of the wheels on the axes I 4 and 23 respectively requires a new truing of the wheels in, order to achieve the best results in lapping. Consequently from the above causes and also by reason of normal wheel wear, the respective wheels 30 and 300. are continually becoming smaller in diameter. When the work-pieces are about to contact the washers I09 and "39a, I remove the wheels 30 and 30a (or only one of them if only one is considerably reducedjn diameter) and the sections may be readily separated by knocking them with a lead hammer, as the cement is not and should not be a permanent adhesive. However, I prefer merely to knock off the small section I08 or I 03a, and then I slide a new-unused section IOI or IOIa upon the spindle 99 or 99a coating the small face thereof with a cement. and then slide the 76 tighten up the nut H0 or lllla as before. The result is a, fresh wheel, which may be trued to exact frusto-conical or other spiral form or shape, and the total discarded or unused wheel volume is indicated by the very close cross-hatching on section IN on Figure 1. How this compares with what would be discarded, were unit wheels used can beappreciated by reference to Figure 1, drawing lines from the outside of flange 91 to the outside of washer lll9.- Furthermore, by means of the construction described, the renewal of wheels may be made very quickly. Preferably wheels are renewed when all sections have been worn so that their large diameters are equal to the original size of their small diameters, as by this procedure a minimum of dressing or truing is required. A circle may'be painted on each wheel, on the small side thereof, to represent this diameter for thesmall wheel I08 or I080,

since eventually every wheel moves to that posi-' tion. It will be noted that all nuts have been shown as spanner nuts which facilitates the assembly and disassembly of the parts.

Although I have described the assembly of the wheels 30 and 30a upon the spindles 99 and 99a with the latter upon the spindles 36 and 360., it is quite convenient to remove the latter spindles from the former spindles for this purpose.

old sectio'ns llll to I01 inclusive, or lid to lMa. inclusive upon the spindle 99 or 980. I then 1 posite wheel in which the variousobjects here- It will thus be seenthat there has been pro-- vided by this invention an apparatus and a cominabove set forth together with many thoroughly practical advantages are successfully achieved.

As many possible embodiments may be made of the above invention, and as many changes might bemade in the embodiment above set forth, it is as be understood that all matter hereinbefore set forth, or shown in the accompanying drawings,

'is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In apparatus of the class described, a pair of tables in parallel relationship, a pair 6f fixed headsone on each table, a pair of movable heads one on each table, spindles journaled in said heads, each spindle extending between a fixed head and a movable head and each movable head being movable in the direction of the spindle axis, and the fixed head on one table being opposite the movable head on the other table, and frustoconical abrasive wheels mounted on said spindles with the large end of one wheel opposite the small wheel of the other.

2. In apparatus as claimed in claim 1, the combination with the parts therein specified of a plurality' of frusto-conical abrasive sections constituting the frusto-conical abrasive wheels.

HERBERT s. INDGE.

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