US1989171A - Shank collar for boring - Google Patents

Description

I 1,989,171 DRILLING, PUNCHING, AND LIKE ES FOR ATTACHING THE SAME Jan. 29, 1935. H. KCHLEN SHANK COLLAR FOR BORING,

TOOLS, AND IN APPLIANC Filed March Patented Jan. 29, 1935 UNITED STATES.

SHANK COLLAR FOR BORING, DRILLING,

PUNCHING, AND LIKE TOOLS, AND IN AP- PLIANCES FOR ATTACHING THE SAME Hans Kiihlen, Rosslau, near Dessau, Germany,

assignor to the firm Flottmann Aktiengesellshaft, Herne, Germany Application March 29, 1934, Serial No. 718,091 In Germany February 20, 1933 2 Claims. (01. 121-32) age of the tools, and affect in particular the collars at the neck of the tools where heavy impact occurs. The impact of the collar, particularly in the case of hollow borers and drills, results in distortion of the fibre of the metal, and breakage frequently results at the thickest part of the tool, where the collar is applied. Various methods of heat treatment, toughening and hardening has been tested for overcoming this defect, without striking success. The use of rubber collars held by clamps is one of these methods, but rubber is' not a material well adapted by its general properties to use in this connection, and secure attachment by clamping is difiicult to efiect. Welding, which has also been proposed, has the defect of involving a degree of heat which is deleterious to the metal, particularly in the case of some alloy steels, and welding does not provide a particularly strong joint. Shrinking the collar on to the neck of the tool, into a shallow depression forming a seat therefor, involves weaking the tool shank. It is well known that even a comparatively minute impression made in the surface of tool steel, as for example an impression of the makers name, or a number, results in quite substantial weakening of the steel.

According to my invention these difiiculties and defects are overcome by using for the collar a coiled metal spring, generally of spring steel, the normal internal diameter of the spring being somewhat smaller than the diameter of the neck of the tool. By diameter of the neck I mean, as the case may be, the diameter of a cylindrical neck or the diameter of a circle within which the outline of a polygonal neck is inscribed. The spring is expanded for placing it on the neck, and grips the neck firmly on contraction. A secure and permanent hold is thus secured, without requiring machining to make a seat for the spring, though of course the spring might be applied to a machined seat in cases where the provision of such a seat does not involve undue weakening. No heat treatment liable to weaken the structure of the metal is required.

To enable the collar to serve also as a resilient cushion or buffer the coils at one or other of its ends may be given an enlarged diameter and pitch, allowing of axial compression.

For conveniently applying the collar to the tool the invention includes an appliance comprising two members pivotally connected by a knuckle having a concentric socket for the spring, with two dogs, one on each member, for engaging respectively the ends of the spring and expanding the same by rotation of either member, the diameter of the socket being somewhat larger than the normal diameter of the spring.

A tool with a collar according tothe invention is shown by way of example in Fig. 1 oi the annexed drawing, the collar being shown in section. An appliance for applying the collar according to the invention is shown in Figs." 2 and 3, Fig. 3 being a side view, showing the device in section, with the spring in the socket and the tool inserted thereinto.

In Fig. 1 or represents the tool and b the coiled metal spring collar, consisting in the example shown of .wire of circular cross-section, but wire of any other convenient cross-section may be used. Two coils b at the right hand end of the spring, facing the bitt, are of slightly enlarged diameter and pitch to allow of axial compression, the other coils lying closely together.

The device shown in Figs. 2 and 3 has a cylindrical socket c for the spring, with an opening at the base so that the tool can be pushed through it. The socket is formed by a hollow boss at one end of an arm i, and this boss is embraced'by an eye e at one end of an arm f, connected to the boss by a screw engaging into a circumferential groove, which allows rotation of either arm in relation to the other. Within the socket, on the arm i, there is a dog 01 for engaging the inner end of the spring, and a dog h for engagingthe outer end of the spring is fixed to the arm f by a screw 9. The dog it is removed for inserting and removing the spring.

By rotating either of the arms in one direction the spring is radially expanded and the coils are thus pressed evenly against the wall of the socket. The tool can then be inserted easily, whereupon the spring is allowed to contract upon it.

What I claim is:

1. ,A shank collar for boring, drilling, punching, picking and like tools, consisting of a coiled metal spring whose normal internal diameter is somewhat less than that of the tool shank which it embraces, and wherein the coils at one end of the spring are of enlarged diameter and pitch, allowing of axial compression for producing a resilient buffer efiect.

2. A boring, drilling, picking, punching or like tool as claimed in claim 1, wherein the coils at one end of the spring are of enlargeddiameter and pitch allowing of axial compression for producing a resilient buffer effect.

HANS HLEN.

Images