US1185901A - Grinding-bur. - Google Patents

Description

W. A. HANCE.

GRINDING BUR.

APPLICATION men JAN. 29. I916.

Patented J une 6, 1916.

m m u w UNITED s'rArns PATENT OFFICE.

WILLARD A. HANCE, or FREEPORT, ILLiNoIs, A ssIGNfoR To smovna MANUFACTURING COMPANY, OF FBEEIE'ORT, ILLINOIS, A CORPORATION or ILLINOIS.

GRINDiNG-BUR.

Specification of Letters Patent.

Application filed January 29, 1916. Serial No. 75,151.

To all whom it may concern:

Be it known that I, WVILLARD A. HANOE, citizen of the United States, residing at Freeport, in the county of Stephenson and State of Illinois, have invented certain new and useful Improvements in Grinding-Burs, of which the following is a specification, reference being had therein to the accompanying drawing. 1

The object of this invention is to provide grinding burs which will lessen the consumption of powerand increase the output without increasing initial cost nor sacrificing durability.

It is well understood that grinding burs of the common metal type are not readily made to run precisely in a given path and that the slightest deviation causes one bur to cut its companion. It is also common to provide means for retarding the discharge from the burs. To prevent initial injury by the burs and to retard delivery are results often secured by closing the grooves of the burs at the margins of the latter by integral metal forming a smooth faced ring to meet the smooth surface of the companion bur and prevent contact of the grinding teeth. This expedient is effectual, but with certain materials it undesirably reduces the output and increases the power used in running the mill. I have found that by closing in the way suggested the outer ends of some of the grooves, on all sides of the axis, and leaving intermediate grooves open, we have all the advantages, and none of the disadvantages of the continuous ring. In grinding oats, for example, the gain is very great.

For illustration annular disk burs are shown although conical burs may be used.

In the drawings, Figure 1 is aplan view showing one working face of an annular bur having alternate grooves outwardly closed by integral metal which can be con-' sidered as part of a broken marginal ring. Fig. 2 is an edge view of a portion of two coacting burs of similar construction. Fig. 3 is a section .on the. line 33, Fig. 2. Fig. 4 shows a segment of a disk bur in which every third groove is closed at the bu'rs periphery. Fig. 5 illustrates two consecutive closed grooves alternating with a single opeii groove.

In Figs. 1 and 2, A, A designate the bodies of two coacting burs of annular disk form. Each has the usual general arrangement of tangential ribs and each has its inner annular portion beveled from the Workingface' toward the inner margin of the ring, and has at regular intervals a rib extended inward to said margin to form a large feeding and breaking rib B the edge of which recedes but slightly fromthe working plane. The intermediate ribs C do not extend to that inner margin, and on the nonbeveled portion of the ring have their edges on the two plates quite as efieotually as the old continuous rings of which these mayv be considered as remaining segments. At the same time material between the rings escapes from alternate grooves and is retained in, intermediate grooves. It is found that practically material does not fill and remain in the closed grooves while passing rapidly out of the open grooves, but that material is carried from groove to groove, material which enters the inner end of a particular groove, open or closed, passes from groove to groove owing to the rotation, and is delivered from a groove at some distance from the groove which it first entered. The material is therefore. of practically uniform fineness when delivered, and because the plates may run very close together, and yet deliver rapidly it is always finely ground. It is not indispensable that single closed and open grooves alternate. Two open grooves may alternate with single closed grooves as in Fig. 4 or with single open grooves as in Fig. 5. Other similar changes may be made,

one or more closed grooves alternating with Patented June 6, 1916. r

working face provided With grooves separated by narrow grinding ribs, some of the grooves at short distances from each other being closed at their outer ends only by integral metal forming peripheral bearing surfaces substantially in the plane of the working edges of the ribs while intermediate grooves are open at their outer ends.

2. A grinding bur having the annular peripheral portion of its Working face provided with thin tangential grinding ribs many of which extend, distinct from their companions, to the periphery of the bur while intermediate ribs are integrally connected at their outer ends by segments having substantially the same height as theribs.

3. A grinding bur having in the annular outer part of its working face tangential grooves separated only by thin grinding ribs, said grooves at short intervals around the periphery of the bur being closed at their outer ends only by integral metal forming bearing surfaces to prevent mutual injury of the ribs of oo-acting burs and obstructing the outward flow of material in XVILLARD A. HANCE.

Vitnesses J. F. DITTMAN, C. L. SAGE.

@opies of this patent may be obtained for five cents each, by addressing the Commissioner of ratents. Washington, D. C.

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