US1145062A - Rotary heel-seat cutter. - Google Patents

Description

A. L. GREEN.

ROTARY HEEL SEAT CUTTER.

APPLICATION man FEB. 6. 1915.

Patented July 6, 1915.

IE a I IE ST L T FFIQ.

ALONZO Il- GREEN, OF LYNN, MASSACHUSETTS, ASSIGNOB TO HAMEL SHOE MACHINERY COMPANY, OF LYNN, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

ROTARY HEEL-SEAT CUTTER.

Specification of Letters Patent.

Patented July 6, 1915.

Application filed February 6, 1915. Serial No. 6,657.

To all whom it may concern:

Be it known that I, ALoNzo L. GREEN, a citizen of the United States, residing at Lynn, county of Essex, State of Massachusetts, have invented a certain new and useful Improvement in Rotary Heel-Seat Cutters, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention has for its object a new and improved rotary heel seat cutter to be employed in the manufacture of shoes, and particularly for trimming from the edge of the heel seat and heel the bur which remains after the heel has been trimmed. Rotary cutters for this purpose are old and well known in this art, and consist of a series of teeth or blades secured to a hub and separated from each other by slots. 7

As previously constructed and employed commercially each of the blades or teeth has been thicker at the front than at the back growing gradually thinner toward the rear of the blade, this being the result of the fact that the edges of the interior surfaces of the blades are arcs of a circle formed about the center of rotation of the cutter and of the fact that the toe or front point of each tooth projects farther from the center than the heel so as to give the requisite clearance. It has been found that cutters, when thus c0nstructed, are objectionable because the greater thickness at the point of the blade makes it necessary to grind the blade so long that the metal is heated and the temper is drawn. It results that the cutter will not hold an edge and requires frequent grinding. After the cutter has been ground a considerable number of times and has been ground down to the point near the heel where the blade is comparatively thin, a small amount of grinding will. form the proper edge on the cutter and the temper is not drawn. The cutter then holds an edge well and is altogether more satisfactory.

I am aware that an attempt has also been made to produce cutters having a uniform thickness of the blades of the teeth by forming their exterior and interior surfaces in concentric circles and then bending each blade outwardly sufficiently to give the requisite clearance. In so doing the structure of the metal in the spoke at the point where the bending takes place is changed; also, a similar change takes place in a portion of the blade adjacent the spoke and a minute depression is formed at this point, giving to the blade an irregular slope toward the heel of the blade. I also find that there is a tendency for the blade to be twisted by bending. Such cutters have proved altogether unsatisfactory in actual use. I am not entirely certain why this is the case, but I be lieve it to be due to the'fact that the respective blades are not given the same amount of clearance and also because the irregular curve of the blade produces friction and consequent heating when the cutter is in use particularly when the clearance has been reduced by frequent grinding. It is also unsatisfactory because a steel must be used which will permit this procedure and such steel is softer and will not take so good an edge.

My present invention therefore has for its object a rotary heel seat cutter so constructed as to obviate the foregoing objections and having teeth of uniform thickness from front to rear thereby requiring a uniform and minimum amount of grinding and holding an edge as Well when the teeth are of full length as when they have been ground back toward the heel. The metal composing the spokes and blade is not bent but is in its original condition, its structure in the finished cutter being uniform with that of the rest of the cutter, and therefore the metal may be of the kind best adapted to take and hold an edge. Also the exterior surface of the blade is perfectly smooth and true and free from depressions.

The invention will be fully understood from the following description taken in connection with the accompanying drawings, and the novel features thereof are pointed out and clearly defined in the claims at the close of this specification.

In the drawings, Figure 1 is a side elevation of a rotary knife embodying my invention. Fig. 2 is a section on line 2-2 Fig. 1, looking in the direction of the arrows. Fig. 3 is a front elevation.

Referring to the drawings, at A is shown the hub, and at B, C, D, E, F and G the teeth. The number of the teeth is immaterial. Each tooth is composed of a spoke 11 and a blade 12. lhe front end or toe of the blade forms the cutting surface and is designated 13 and the rear end or heel is designated 14.

At is indicated the flange which rests against the guard (not shown) by which the knife is guided in the crease between the heel seat and the upper of the shoe. The space between each pair of teeth is formed by cutting a slot at one edge of which is substantially tangent to the hub A. Thecutting edge is formed by grinding the surface 16 along the line which is also substantially tangent to the hub. It will be seen by carefully comparing the position of the point 13 and the point 14 that the cutting edge 13 of one toothis at a greater distance from the center than is the heel of the adjacent tooth. In other words, a suitable clearance is given each blade. It will also be seen that .the thickness of the blade on the side edge is uniform from the point 13 to the point 1 1, or to state the matterdifierently the curve formed by the line Z) (seeFig. 1) which represents the outer surface of the tooth is concentric With the curve 0 which represents the inner surface of the tooth. It will be understood of course that both of these curves are spirals being formed by a cutting tool which is given a movement radially from the center of rotation of the blank. two curves Z) and c are therefore conveniently referred to as portions of spirals.

The cutter is formed from a suitable blank of steel by a specially constructed lathe or machine in which the cutting tool is given a suitable motion radially of the center of rotation of the blank, the movement of the cutting tool being the same when the curve 6 is formed as when the curve 0 is formed.

It will be seen that the cutter as thus con- Copies of this patent may be obtained for five cents each, by addressing the The i doing the metal of which the blade is com posed is not heated, the temper is not drawn, and the finished cutter retains its'cutting edge. Furthermore, the time required to grind the cutter is reduced to about one half that required to grind a cutter of the type having blades of diflerent thickness from the toe to the heel of the blade.

I also find that all heating due to friction with the heel when in use is done away with,

the blades having a smooth true outer surface and equal clearance. Also I can make these cutters of the quality of steel best adapted to take and hold a cutting edge.

What I claim is:

1. The improved heel'seat cutter which comprises a hub, spokes projecting from the hub, and blades on the said spokes, each of said blades having the point or cutting edge at a greater distance from the center of rotation than the heel, and said blade being of substantially uniform thickness from the cutting edge to the heel ofthe blade, the structure of the metal of which said spokes and blades are composed being uniform throughout.

2. The improved heel seat cutter which comprises a hub, spokes projectingfrom the hub, and blades on said spokes, each of said blades having the point of cutting edge at a greater distance from the center of rotation than the heel, said blade being of substan tially uniform thickness from the cutting.

edge to the heel of the blade, the curves formed by the inner and outer edges of said blades being portions of concentric spirals.

In testimony whereof I afliX my signature, in presence of two witnesses.

ALONZO L. GREEN.

WVitnesses 7 Gnoncn P. DIKE, ALICE H. MORRISON.

Commissioner of Patents,

Washington, D. C.

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