US 3916579 A
A grinding wheel has slots angularly disposed across the peripheral grinding face. A tapered recess is provided at the leading radial edge of each slot so as to provide increased air flow through the slots as the wheel rotates. The radially outward edges of each slot are chamfered to increase the available grinding area.
Description (OCR text may contain errors)
United States Patent Waller et al. Nov. 4, 1975 SLOTTED ABRASIVE WHEEL 2,837,878 6/1958 Johnson 51/206 R Inventors: Gustav Martin Waller, Geneva; 3,579,928 5/1971 Held 5l/356 g 'a g f' Landmark Charles FOREIGN PATENTS OR APPLICATIONS 1,132,479 6/1962 Germany 125/15  Assigneez Tunco Manufacturing Inc., Geneva,
Ill. Primary Examiner-Donald G. Kelly  F1led: Feb. 10, 1975  Appl. No.: 548,773
[ ABSIRACT [2%] }l.S.CCll 5l/2il6 P; 51/356 A grinding wheel has Slots angularly disposed across lllt. I the peripheral g g face. A tapered recess i p  Field of Search 51/356 206 206 vided at the leading radial edge of each slot so as to 51/206'5 125/15 provide increased air flow through the slots as the wheel rotates. The radially outward edges of each slot  References C'ted are chamfered to increase the available grinding area.
UNITED STATES PATENTS 8/1936 Sherk 51/206 P 6 Claims, 4 Drawing Figures US. Patent Nov. 4, 1975 3,916,579
SLOTTED ABRASIVE WHEEL Grinding wheels have been used to grind away the black rubber from the outer wall of automotive tires to expose the white rubber and provide thereby the socalled white wall tire. The grinding operation, for many years after its inception, was extremely inefficient because the rubber which was ground from the tire tended to rapidly clog the grinding wheel and greatly reduced its efficiency and working life. Such grinding wheels also tended to overheat and this also contributed to short wheel life.
The problem was partially overcome by the addition of angularly disposed slots in the peripheral grinding face of the wheel, thereby providing reservoirs through which the fine residue of ground-up rubber particles could escape. Such slots also, by flow of air therethrough as the wheel rotated, alleviated the build-up of heat resulting in a more efficient wheel with a longer grinding life. These wheels, however, were still not completely satisfactory in that they retained some tendency to clog and there still was an objectionable bui1dup of heat during a grinding operation.
It has been found that increased air flow can beattained by the provision of a tapered recess in the face of the wheel at the leading edge of each wheel slot. The purpose of the recesses is to relieve slightly the leading edge of each slot so that the trailing edge can scoop up an increased volume of air and direct it down the slot to effectively clear out the residue of ground rubber.
It is an object therefore, of the present invention to modify the slot structure of a slotted grinding wheel so as to increase the efficiency and life of the wheel.
Other objects will be apparent from the following description and accompanying drawings wherein:
FIG. 1 is a side elevational view of a grinding wheel incorporating the features of the present invention;
FIG. 2 is an end elevational view of the grinding wheel;
FIG. 3 is a fragmentary sectional view taken substantially along line 3-3 of FIG. 2; and
FIG. 4 is a fragmentary sectional view taken substantially along line 4-4 of FIG. 2.
Referring now to the drawings, a grinding wheel includes opposed faces 12 and 13 and a peripheral surface 14. The surface 14 and, if desired, the faces 12 and 13 are provided with an abrasive coating. The wheel may include hubs 16 and a central bore 18 for mounting the grinding wheel on a drive shaft or the like.
Transverse slots 20 are spaced around the peripheral surface 14, the slots being disposed preferably at an angle of approximately 50 relative to the wheel axis 22. The number of slots will vary with the wheel diameter and typically a 6 inch diameter wheel may include 6 slots while a 12 inch diameter wheel will include 18 slots. The width and depth of the slots will also vary as desired but preferably may be approximately inches wide and /4 inches deep.
The wheel face, at the leading edge of each slot in the direction of wheel rotation, is provided with a tapered recess 26. The tapered recess 26 originates at the wheel face ahead of each corresponding slot in the direction of wheel rotation and tapers inwardly from the face and toward the slot. The recess preferably has a depth, radially of the grinding wheel, substantially equal to the depth of the corresponding slot. The taper angle of the recess, in a direction away from the grinding wheel face, may vary considerably and still provide the advantage of increased air flow. However, an angle of approximately l0 has been utilized and found to be satisfactory.
With the provision of the relief at the leading edge of each slot, sufficient air is picked up to clear the residue of ground rubber out of the slots and thereby provide a cooler running grinding wheel and one which will have considerably less tendency to clog. The wheel also tends to run much more quietly than prior art slotted wheels and it is believed that this characteristic results from the particular angularity of the slots. The surfaces of the recesses may also, if desired, be provided with an abrasive coating.
It is advantageous also, to provide'recesses (see FIG. 2) at both faces of the wheel and at diagonally opposite edges of each slot so as to accommodate wheel rotation in either direction.
Still greater advantages can be obtained by the provision of chamfers 28 at the radially outermost edges of the slots at the juncture thereof with the peripheral face of the wheel. Such chamfers are coated with abrasive material and provide a lead-in surface for the cutting edge and thereby increase the grinding area which is presented to the material being ground. Such chamfers also substantially eliminate the problem of wearing away the abrasive material from the otherwise sharp corners of the slot.
What Is claimed is:
1. A grinding wheel having opposed faces and-a peripheral abrasive coated grinding surface; a plurality of transverse slots in said peripheral surface, said slots being angularly disposed relative to the wheel axis and extending across the entire width of the peripheral surface; the wheel face, at the leading edge of each slot in the direction of wheel rotation, being recessed at said edge for approximately the full radial depth of the slot so as to provide increased air flow through the slots as the wheel rotates.
2. A grinding wheel according to claim 1 wherein each recess originates at the wheel face ahead of the corresponding slot in the direction of wheel rotation and tapers inwardly from the face toward the slot.
3. A grinding wheel according to claim 2 wherein the angle of taper of the recess is about 10.
4. A grinding wheel according to claim 1 wherein corresponding recesses are provided in both wheel faces, the recesses for each slot being at diagonally opposite sides thereof to accommodate wheel rotation in either direction.
5. A grinding wheel according to claim 1 wherein the outer transverse edges of each slot are chamfered and the chamfered surfaces are coated with abrasive material.
6. A grinding wheel according to claim I wherein the slots are disposed at an angle of approximately 50 from the wheel axis.