US1663310A

US1663310A - Segmental grinding wheel

Info

Publication number: US1663310A
Application number: US651350A
Authority: US
Inventors: William T Macaulay
Original assignee: Carborundum Co
Current assignee: Unifrax 1 LLC
Priority date: 1923-07-13
Filing date: 1923-07-13
Publication date: 1928-03-20
Anticipated expiration: 1945-03-20

Description

alt d1 29, 1928. 3,663,310

w. T" M AULAY SEGMENTAL GRINDING WHEEL Filed July 15, 1923 fwdw M ATTORNEYS Patented Mar. 20, 1928. UNITED STATES PATENT orrlcs.

WILLIAM '1'. MAOAULAY, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE CABBOBUNDUI- COMPANY, OENIAGABA FALLS, NEW YORK, A CORPORATION OF PENNSYLVANIA.

SEGHENTAL GRINDING WHEEL.

Application filed July 13,

The present invention relates broadly to grinding wheels, and more particularly to inding wheels ofithe segmental type used or plane surface grinding. i

In grinding plane surfaces it is usual to use a cylindrical wheel, the thickness of the cylinder being much less in a radial direction than in, an axial direction, and the grinding being done on the face of the Wheel normal to its axis. This form of grinding wheel is very largely used in the surfacing of iron, steel and metal parts. In the use of these wheels where there is a large part of the working surface of the wheel in contact with the work being ground, the most important desideratum is a free cutting wheel which will not glaze or gather metal particles on its face, and which will not burn or leave chatter marks on the work ground. It is therefore usual to employ wheels of the softer grades. The bond holding the abrasive grains in wheels of soft grades being of low tensile strength, these wheels. are

fragile and require careful handling in mounting and in use. They are also easily broken in transportation.

I have discovered that this operation of plane surface 'ndin can be very economicall and satlsfactori y carried out by employmg this cylindrical shape of wheel in the form ofsegments instead of a solid wheel, b reason of the fact that in a wheel in the orm of segments, whether the segments, are set with a space between them or are set together with ends touching, the break in the! contact surface supplies clearance spaces and this promotes the free and rapid cutting qualities of the wheel and avoids glazing, giving results not attainable with the solid;cylindrical wheel. Moreover se ments are cheaper to produce than a solid wheel, because the labor of moldin' and burning smaller pieces is very muc less, and they can be handled without danger of breakage;

A serious difiiculty involved in the use of the segmental typeof grinding wheel for this purpose, however, is to provide a satisfactory mounting for the segments owing to their fragile nature and to the tendency of centrifugal and other forces to unseat them.

By the present invention I have provided a form of mounting particularly suitable for this type of wheel, and whereby the 1923. Serial No. 651,350.

n the accompanying drawings, I have shown, for purposes of illustration only, certain embodiments of my invention, it being understood, however, that the drawings do not define the limits of the invention, as changes may be made in the construction therein disclosed without departing from the spirit of my invention or scope of my broader claims.

In the drawings:

Figure 1 is a vertical sectional view through a segmental grinding wheel embodyin%my invention;

igure 2 is a bottom plan'view of the wheel shown in Figure 1;

Figures 3 and 4 are plan views, and

Figures 5 and 6 are sectional views illustrating modified forms of segments.

Referring to Figures 1 and'2, there is illustrated a grinding'wheel comprising a metallic face plate. 1 mounted upon a shaft 2. Detachably mounted upon the under side of the periphery of this face plate by screws 4 is a metal ring-3. The ring is provided with: an annular channel 5 therein, formed by inner and outer flanges having undercut walls, whereby the channel has a dovetail form in cross section. A plurality of segments 6 are seated in the channel. The sides of the portions of the se ents which are seated in the channel may recessed to give the base portions of the segments a dovetail cross sectional form also. The-spaces between the sides of the base portions of the segments and the undercut walls of the flanges of the ring are filled with a suitable cement, such as sulphur. The walls of the flanges of the ring, instead of bein undercut, may have vertical sides left roug as they come in casting, in which case the cement .is often sufiicient to hold the segments in case, however, I emplo segments 3" or more in hei ht, 'I referab y secure a thin steel band a ut 1 wide and thick around the periphery of the segments. This band is provided with a clamping and adjusting screw 8, which should be tightened 'just enough to hold the band in place. This.

band is spaced from the ring 3 and assists in holding the segments in place against centrifugal force tending to unseat them, and acts as a safety guard in case a segment should break. The band should be located about from the cutting face of the segments, and as they wear away, it should be adjusted toward the ring.

When the wheel is put inuse and brought up to working s eed, there is a high centrifugal force ten ing to throw the segments outward in a radial direction and cause the outer ed e of the base of each se out to bear against the outer flange of t e channel. This results in a tendency of the seg ments to tip up,that is, there IS a tendency for the inner bottom edge of each segment to rise. This is overcome by means of the inner flange having the undercut wall. This undercut wall cooperates with the inneredge of the base ofeach segment and the-cement thereon to hold'the segments rigidly to their seat in the channel against the centrifugal force tending to unseat them. The torsional strain on the segments in the act of grinding also tends to pull the segments out of the channel, and this strain is likewise opposed and met b the arrangement of the undercut flanges between which the segments are cemented.

Another marked advantage of this type of construction is that it is possible to assemble a number of rings with various grades of segments, and change the grinder from one grade to another by simply detaching the ring with its set of segments of one particular grade and replacing it with another ring having segments of a different grade.

In comparing the relative elhciency of my segmental wheel with asolid wheel, I find that the time of grinding a given piece of work is reduced 10 to 15 per cent and upwards, and on the general run of work, such as large and small pieces of hard and soft steel, torgings and the like, a set of segments will last approximately 50 per cent longer than an equivalent-length of a solid wheel. For the general run of work the segments may be set in contact with no spacing, but on bread surfaces 6 square or over, it is better to space the segments, using in the example I have cited ten or eleven segments in place of twelve segments, as these spaces between the segments greatly cut down the tendency to glaze.

In Figure 3 l have shown'a modified form of segment in which the ends lap one against the other while maintaining an open space between the segments in a peripheral direction. This results in a more rigid construction which prevents some vibration and has advantages in grinding certain classes of work.

In Figure 4 ll show a modified form of segment in which the ends are locked by a tongue and groove design.

lnFigure 5 ll show a modified form of a segment in which there is a taper from the top of the segment to the bottom, the rinding face being narrower than the base, T have found that as the segment wears down, it is possible to use a wider face, that is a wider inding surface, and maintain the same rigidity and the same freedom from vibration, and this is accomplished by the tapered form, because when the segment is new and the rinding face is at some distance from the ase of the segment where it is held in the ring, the face is comparatively narrow and gets widerjas the segment wears down and the necessity for rigidity becomes less.

It will be noted in this form also that the distance across the base of the segment from a to b is [greater than the width of the opening in the ring from o to d. The segments are inserted by first tipping up each segment and bringing the point 0; thereof to the point e in the bottom of the channel of the ring, then the segment can be seated in the channel, as the point I) of the segment will clear point d of the ring.

In Figure 6 I show a segment having straight sides but with the same proportioning of the base of the segment to the width of the opening as in the Figure 5 construction.

Another important advantage of the present invention arises from the provision of the channel in the metal base plate having a dovetail form in cross section for cooperation with segments having bases with a' similar cross sectional form, whereby the segments are securely held in place against the centrifugal force tending to unseat them.

I claim: H

1. In a segmental grinding wheel, a flanged center disk, a ring member on the flange whose diameter is substantially the same as the diameter of the central ortion of the disk, the ring and disk having contacting shoulders by means of which the ring is centered on the flange of the disk, means for securing the ring to the disk, a channel in the face of the rin at the side opposite the contacting shoul ers and a plurality of grinding'sections in the channel.

2. In a grinding wheel, a ring having a channel in the facethereof of inwardly increasing width, segmental grinding stones in the ring having base portions of inwardly increasing width, the greatest width of the base portions of the stones being no greater than the narrowest portions of the channel so that the sections can be inserted in the channel, and a solid filling material filling the voids between the undercut sides of the channels and the expanded base portions of the se8ments.

reee eio a 3. In a grinding Wheel, a ring having a narrowest porfiions of the channel so that channel of dovetailed cross-section in the the stones can be set in and removed from 10 face thereof, a plurality of segmental grindthe ring, and filling material poured around ing stones set into the channel, said stones the base of the stones and filling the chan- 5 having base portions received in the channel for retaining the stones in the channel. nels which are of dovetailed cross-section, In testimony whereof I have hereunto set the maximum Width of the base portions my hand, of the stones being no greater than the WILLIAM T. MAGAULAY.