US1729585A - Segmental abrasive wheel - Google Patents

Description

Sept. 24, T1929u T. LARSSON ET Ax..

SEGMENTAL ABRAS IVE WHEEL Filed May 19, 1924 Patented Sept. 24, 1929 STATES treni* ori-ICE THURE LARSSON AND HUGO W. H. BETH, OF WORCESTER, MASSACHUSETTS, ASSIGNORS TO NORTON COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS SEGMEN TAL ABRASIVE WIEEL Application filed May 19, 1924. Serial No. 714,322..

An attempt has been made to use ceramic bonded articial abrasives for such wheels but it has been found that they break easily or their corners chip off., thus making the use of such wheels expensive. Owing to problems met in manufacturing` it has been found desirable to make the pulp grinding stone of a number of segments, andto clamp these together to form the complete wheel; but the necessity for driving the stone under the enormous restrainingr pressure of heavy logs held against the wheel has made it difficult to mount the segments on a spindle and clamp them between driving' flanges without increasing the liability of breakage.

lt is, accordingly, an object of our invention to provide an improved grinding wheely of this type which may be economically man ufactured and easily assembled, which will give a long and elicient life of service, andl which is so constructed that the abrasive material will not become cracked or broken due to the heat expansion or the frictional strains of normal usage.

It is a further object of our invention to provide an improved mounting for the segmentsof a wheel whereby the segments may be held rigidly in position under a clamping pressure which is so uniformly distributed that the driving flanges may be adjusted tightly in place without serious results.

lVith these and other objects in view, as will be interned in the following enclosure, our invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings. in which like reference numerals indicate like parts:

Fig. l is a section on the line l-l of Fig. 2 showing one embodiment of our invention;

Fig. Q is a vertical central section through' the grinding wheel; and

Fig. 3 is an enlarged sectional detail show- 1n g the mounting of the abrasive segments.

@ne embodiment of our invention may comprise a grinding wheel made up of a plurality of rows vof closely positioned abrasive segments mounted on a rotatable support, such as a drum. These segments may be secured in position by means of clamping flanges or plates engaging the exposed faces of the end segments on the wheel which are so mounted that they may be adjustahly moved toward each other to clamp the segments firmly therebetween. The segments are so shaped that they will lie close together adjacent to the cylindrical grinding surface of the wheel; and between the inner faces of adjacent segments is a clamping or friction member which serves when the clamping flanges are adjusted into position to frictionally or otherwise engage the inner sides of the segments and aid in holding them in position. rThe clamping or friction member, which may be in the shape of a ring mounted in an annular groove formed between adjacent faces of the segments, is freely movable parallel with the axis of the wheel and relative to the surface of the drum, so that the pressure of the clamping flanges may be distributed throughout the wheel. The surface of the wheel is made up of a large number of small abrasive segments to minimize the liability7 of breakage from heat eX- pansion; and in order that the segments may be supported laterally and protected from forces tending to break the Wheel, the crevices are filled adjacent to the surface of t-he wheel with a filler, and preferably one of a cementitious nature, which will unite with the sides of the segments and form them into an integral solid body.

As shown in the drawings, a wide faced wheel may be formed of 'a plurality of disk shaped rovs 10 of segments which are so formed and arranged as to provide a cylindrical grinding surface ll. The segments l2 may be individually shaped, as shown in the drawings, as quadrants or in other suitable forms, and their inner surfaces are made concave so as to form an internal cylindrical surface 18 which will fit on a rotatable snpport andso position the segments properly.

The rotatable support may be Ishaped as a large drum 15 which has an outer cylindrical surface, and this drum is in turn removably mounted on a` spindle or driving shaft 16 by means of the annular webs 17 which have a sliding fit on the shaft.

In order to clamp in position these rows 10 of abrasive segments and to drive them ro- `tatively, we provide end flanges or driving members 2O which have central openings 21 screw threaded to the spindle 16. 'Ihe threads ofthe two driving flanges are so disposed, one a right-hand thread and the other a left-hand thread, that rotation of the spindle 1G in normal operation tends to tighten the hold ofl the flangesupon the abrading elements. As illustrated, these flanges project beyond the outer periphery of the drum and the assembled abrading disks are of such width thato they project slightly beyond the ends of the drum so that the flanges may be clamped against the outer surfaces of the end segments.

In order to transmit the clamping pressure uniformly throughout the abrading wheel and'to prevent breakage of the same, we provide frictional driving rings 24,'Whose inner peripheries are such as to fit upon the outer surface of the drum and the outer peripheries are as great as those of the driving anges 20. In order that the adjacent edges of the rows of abrasive Isegments may be close together, we cut a groove 25 in the inner faces of each segment in one row of such a size and depth that a ring 24 may lit therein. These rings j may have parallel plane faces 26 and 27, butl we prefer to make them slightly wedge shaped in order to assist in holding the abrasive segments in place, and particularly in case of breakage of any of the segments. To this end, each groove 25 is made slightly shallower adjacent the inner periphery of the wheel, and each ring 24 is provided with a tapering face on one side to fit the groove. The other side of the ring is made. parallel with the plane face 29 of the other side of the adjacent row of segments which lies in a diammetrical plane of the wheel.

Since the two faces of each adjacent row of segments should he accurately made, we may provide each side 29 with a central raised portion 30 whichmay be trued off to the desired extent 'to make a careful driving fit. In order thatall abrasive segments may be made alike, it will be observed that one-half of them are shown in Fig. 1 as facing in one direction and the other half inthe other, so that at the center of the wheel, two of the wedging and segments make close lits with each other and with the rings, so that the pressure is evenly distributed and each segment is subjected to lthe same driving forces. This arrangement of frictional driving and locking rings between each pair of adjacent abrasive seg: ments provides such a mounting that the wheel may be subjected to the enormous pressures involved in grinding wood pulp without danger of breaking the wheel under normal usage.

`'Ihis type of grinding wheel is particularly adapted for grinding wood pulp in which operation logs are held against the peripheral surface of the wheel under high pressure. If the wheel is intended for such severe usage, We propose to fill the crevices, and particularly adjacent to the cylindrical grinding surface, with a filler, and preferably a cementitious filler, such as cement, which will adhere to the segments and unite them into a rigid, unitary wheel structure. This filler supports the sides of the segments so that any lateral thrust will'be transmitted easily from one segment to another and thus be absorbed without endangering the wheel. Also, it prevents slivers of wood or the like from lodging in the crevices between the segments and sopassing through the grinding zone and thus producing an inferior grade of wood pulp. Moreover, if the crevices betweeen the segments are filled to the outer cylindrical surface of the wheel, there are no projections or depressions for the logs to bump or strike forcibl against, and sooner or later break off chips rom the Wheel. In this way the life of the Wheel is materially lengthened. It is also to be explained that the clamping or friction members 24 may be made of suitable metals, such as lead or other soft materials, which may have agood driving hold on the abrasive segments or otherwise serve the purposes specified.

`Having thus described our invention, what we claim as new and desire to secure by Letters Patent is: .j

1. A wood pulp grinding wheel comprising a rotatable support, a plurality of rows of abrasive segments arranged thereon to form a cylindrical grinding surface, a freely movable friction member located between and in engagement with the inner faces of adjacent segments, and clamping flanges associated with therotatable support and adjust- 4ably engaging the exposed faces of the end `in the drum to support the same, the inner opposed faces of adjacent segments having a groove, a freely movable, friction member lli together adjacent to the wheel periphery,

and clamping flanges adjustably mounted on the spindle and engaging the exposed faces of the end segments which serve to press the segments and friction members into frictional contact and to hold the segments on the drum.

3. A grinding wheel comprising a rotatable support, a plurality of rowsof abrasive segments arranged thereon to form a cylindrical grinding surface, a freely movable clamping member between and engaging the inner faces of adjacent segments, clamping members associated with the support and serving to press the segments and the freely movable clamping member together and to hold them in assembled relation, and a iilling material in the crevices between the segments adjacent to the' grinding surface.

4. A grinding wheel comprising a wide drum, a spindle to support the same, a plurality of rows of narrow abrasive segments on the drum arranged to form a cglindrical grinding surface, the inner faces o adjacent segments which are parallel with the wheel ends being closely positioned and shapedto form a groove therebetween, a freely movable clamping member', which is independent of the drum located in the groove and frictionally engaging the sides thereof, clamping flanges engaging the end faces of the wheel and cooperating with the drum to press the segments and clamping member together and to hold the segments in position', anda cementitious filler in the crevices between the segments which unites them into va rigid Wheel structure.

5. A grinding wheel comprising a substantially cylindrical support, a spindle mounti able therein, a plurality of annular rows of abrasive se ments on said support and arranged to orm a cylindrical grinding sur-4 face, the inn r sides of adjacent rows of seg-v ments being shaped to form an annular groove, a freely movable ring in the groove having faces frictionally engaging the segments, clamping flanges independent of said support which are adj ustably mounted on the spindle and engage the outer faces of the segments and thereby. serve to force the segments and ring into frictional contact, and a cementitious filler in the crevices between'adjacent segments which unites the segments and support intofa rigid wheel structure.

Signed at Worcester, Massachusetts, this 17th day of May, 1924.

HUGO W. H. BETH. THURE LARSSON.

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