US1165989A - Threading-die. - Google Patents

Description

W. J. McINTY RE & D. WEIR.

THR EADING DIE. APPLICATION FILED MAR. 3, I915.

Ll65,989. Patented Dec.28,1915.

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WILLIAM 3.,MCINTYRE AND DAVID WEIR, OF HARTFORD, CONNECTICUT, ASSIGNORS TO THE ALLEN MANUFACTURING COMPANY, OF HARTFORD, CONNECTICUT, A COR-PO- RATION OF CONNECTICUT.

THREAIDINGr-DIE.

Application fiIed March 18, 1915.

To all whom it may concern.

Be it known that we, VVILLIAM J. McIn- TYRE and DAW'D WEIR, both citizens of the United States, residing at I-Iartford, in the county of Hartford and State of Connecticut, have invented a new and useful Improvement in Threading-Dies, of which the following is a specification.

This invention relates to those devices which are provided for cutting threads on screw bodies, bolt rods, tubes, pipes and other cylindrical pieces of metal.

In the common form of solid, split or open threading die the chasing teeth, which cut away the metal to form the thread, usually extend completely through the body of the die, that is, substantially all of the teeth from one face of the die body to the other are utilized as chasing teeth. This is ordinarily accomplished by having the clearance openings, which divide the threads into segments, extend all the way through the body. With these dies if the stock to be threaded, especially if it is a long rod of steel, varies ever so slightly in diameter, or if one section is a little harder than another, it frequently happens that the chasing teeth do not take hold evenly; they sometimes gouge or dig in, particularly as the teeth become dull, and consequently the threads will not be absolutely uniform in section and the pitch will change, for the pitch of the thread formed by the commonly used dies depends entirely upon the pitch of the out which is being made so that if the cut varies the thread alters. Furthermore, the commonly used die is inclined to. load up with chips which injure the thread when the piece being threaded is reversed and unscrewed or backed out of the die.

The object of this invention is to provide a very simple form of die which will eliminate the enumerated difliculties and 'cut a thread on a screw bolt or other article,

only part way through the body, and with Specification of Letters Patent.

Patented Dec. 28, 1915.

Serial No. 15,164.

a pilot thread of the same pitch extending from the inner chasing teeth to the back face of the body. This is accomplished by forming the clearance openings between the chasing teeth only part way through the body instead of entirely through the body, as in the common form of die, and as a result the pilot thread in the die draws the screw or bolt by the thread which is out past the chasing teeth which do the cutting with a uniform lead.

In the accompanying drawings Figure 1 shows a front view of a form of split die which embodies the invention. Fig. 2 shows a section on the dotted line 22 on Fig. 1, and Fig. 3 shows a back view of the same die. Fig. a shows a front view, Fig. 5 shows a section on the dotted line 5-5 on Fig. 4, and Fig. 6 shows a back view of a solid die of little different shape.

The die bodies 1 shown are circular in outline and through the center are openings 2. The walls of these openings are provided with threads of the desired pitch. In the form first shown clearance openings 3 are made from the front, part way through the die body. These clearance spaces open into the central. threaded opening so as to, for a part of the distance through the body, sepa rate the thread into segments. This forms sections of the thread into chasing teeth 4 and leaves the remainder of the thread 5 to act as a pilot or lead.

In the second form illustrated the clearance openings 6 are cut out to the edge of the body. This leaves the chasing teeth 7 on the inner edges of segmental portions 8 011 the front face of the die. The remainder of the thread forms the pilot or lead 9. The bodies may be solid, as indicated in Fig. 2, or may be split, as shown in Fig. 1. The pitch of the thread through the central opening is uniform, but it is desirable to have the section which forms the pilot or lead slightly larger in diameter than the section which is divided to form the chasing teeth, so the stock will not bind in the pilot section. After the screw body or bolt rod which is being threaded reaches the pilot thread in the die it is drawn forward uni formly thereby so that the chasing teeth will continue to out the same amount and on exactly the same pitch, This insures an absolutely uniform thread on the screw or bolt from one end to the other, regardless of any slight variation in the diameter or any change in degree of hardness or softness of the stock.

As a screw formed with this die will have a thread of uniform pitch from one end to the other and the thread teeth will be exactly the same, it can be cut to fit within the tapped part with which it is to be used closer than is possible with the old form of die wherein the pitch is likely to vary and cause the screw to bind unless it is cut sufliciently small to make a somewhat loose fit with the part into which it is to be screwed.

the chasing teeth substantially the remainder of the distance through the body.

2. A solid threading die having a body with a threaded opening extending from one face to the other, and clearance openings extending from the front facepart way only through the body at the sides of and communicating with the threaded opening, whereby a portion of the thread will be divided into segments to provide chasing teeth and a portion of the thread will be continuous to provide a uniform feed for the stock out by the chasing teeth.

3. A solid threading die having segmental chasing teeth that extend part way through the body, and a continuous pilot thread that extends in continuation of the chasing teeth substantially the remainder of the distance through the body, said pilot thread having the same pitch as the chasing teeth and being slightly larger in diameter.

lVM; J. MoINTYRE. DAVID WEIR. WVitnesses S. K. DIMooK, TERRY J. GHAPI Copies of this patent may be obtained for five cents each, by addressingthe .Gommissioner.of Patents,

Washington, D. C.

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