USRE8910E - Improvement in screw-cutting dies - Google Patents

Description

UNITED {Strains I PATENT OFFICE.

JOHN H. VINTON, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR- TO FRANK ARM STRONG.

lMPROVEMENT IIN SCREW-CUTTING ours.v

Specification forming part of Letters Patent No. 308,870, dated October 8, 1878; Reissue No. 8,910, dated September 30, 1879; application filed February l7, 1879.

To allahomitmag concern:

Be it known that I, JOHN H. VINTON, of Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in ScreW-Outtin g Dies and Holders; and I do hereby declare that the following is a full and exact description thereof, reference being had to theaccompanying drawings, making part of this specifi-' cation.

My invention relates to certain improvements in the construction of screw-cutting dies and plates, and their application to pipecutting machines.

My invention has for its object to so form the cutting-dies that they shall cut oi. the excess of metal at the starting end, and at the same time lead the pipe or screw-blank in, thus avoiding the necessity of pointing or filing the article to be threaded; and it also has for its object to so form the plate and platehold'er that the former shall be firmly held in position, while the latter shall be capable of connection with pipeor screw cutting machines, as at present made, for the reception of solid dies. Previous to my invention dies forcutting threads have usually been made solichand in some cases in parts; but in all cases the threads in the dies have been tapped or cut of a-'uuiform diameter throughout the entire thickness of the die, and in order to facilitate the entrance of the pipe -or bolt to, be threaded it has been necessary to cut away the initial portion of the thread on a taper, leaving practieally at such-points no cutting threads orteeth, but simply flat cutting-edges, which must shave on the excess of metalfroin' the end of the pipe or blank to be threaded before the subsequent cutting-th'ieads of the die can begin to cut or perform their operation.

By this construction great power is necessary to induce the fiat cutting-edges to perform their work. and they do not serve to lead the material being operated upon to the cutting-threads:

One part of my invention is designed to overcome these disadvantages; and consists in cutting the threads of the die on two tapers, the enlarged or initial taper serving to grasp the pipe, remove the excess of metal, and lead the pipe to the threads of less taper, which latter cut the threads upon the end of the pipe, as will be hereinafter more fully explained.

Prior to my invention ithas been customary to use solid or non-adjustable dies with pipe-cutting machines, and the heads of all such machines have been made and adapted to receive such dies, so that adjustable dies, which are necessarily longer'than the solid dies, could not be titted into the head of the machines.

Another feature of my invention relates to so forming the plate or die holder that it may be readily secured within a suitable independent head of greater length than the machine-head, and so forming the die-plate holder that it in turn may be readily attached to the standard machines as at present used; and myinvention, therefore, consists in a dieplate for adjustable, (lies formed with lugs or extensions on each side of the die-adjusting screws, extending longitudinally beyond said screws, so that when placed in a rectangular holder the said lugs will hold the die-plate against turning, and at the same time protect the adjusting-screws against accidental move ment..

My invention-further consists ofa die-box adapted to receive the dieplate, and also adapted to enter and be supported within the ordinary die-recess in the head of pipecuttin g machines.

In order that those skilled may make and use my invention, I will proceed to describe inv detail. the peculiarities of construction; and operation, referring'by letters to the accompanying drawingsfin which- Figure 1 is a top or plan view of my invention as applied to the head of a pipe-cutting machine. dies and die-plate. Fig. 3 is a top or plan view of a die embodying my invention; and Figs.-4 and 5 are cross-sections at the lines a: a: and y y, respectively.

Similar letters indicate like parts in the several figures.

A represents the head of an ordinary pipe Fig. 2 is a rear-side elevation of the used a rectangular cutting machine, formed with a rectangular vertical recess adapted to receive the ordinary solid dies, which are usually of the same size as said recess; butwhere smaller dies are box or bushing is some-. times employed.

B is my improved cast-iron box or die-plate holder, the rear portion of which is formed so as to enter the recess in the head of the machine. Projecting forward, it is extended laterally, as seen at G O,'and again extended laterally, asseen at D D, then forward and returned toward the center, leaving a central opening, E, for the passage of the pipe. By this form and construction a recess is formed for the securing-nuts Fof the dieplate, (which, in the manner of securing the dies adjustably, is preferably such as described in Letters Patent granted to Horace'GI-ifiing, dated April 6, 1875,) and a front recess is also formed for the reception of the die-plate G, the ends of which are projected to form lugs H, which, when the.

dieplate is in position, lie adjacent to and in the same plane with the ends of the box or receptacle. These lugs H, it will besee'n, extend a distance not less-than the length ofth'e die-adjusting screws I, and any tendency of the die-plate to turn is prevented by the contact of said lugs with the box, while they at the same time protect the ad'usting-screws against accidental movement.

It will be observed that by the peculiar formation of the box or receptacle B, dies and die-plates longer than the head of the standard machines may be used, and as the dieplate box or holder extends forward, a very short piece of pipe may be operated upon by the dies. i

The hickness of the front of the box in a ter of an inch, thepipe-holder may approach to within that distance of the first thread of the cutting-dies. Y

' in g a greater taper than the remaining portion,

the advantage of this construction being that the teeth or thread of greatest taper and diameter permit the introduction of the end of a pipe or bolt-bar, (which isusually enlarged or burred when being cut into. section s,) and by reason dies the pipe or v grasped and led into the die. This construe tion enables the die to immediately graspthe pipe or blank, and, while cutting it, it at the same time leads it to the subsequent thread or cutter of less taper, which cuts it to therequired gage, in contradistinction to the present double-taper die, which is simply a reduction of the height of the thread, producing a flat surface that shaves off the excess of metal on the pipe or blank before it can reach the actual thread-cutting portion of the die.

It is especially desirable that the. die should have a double taper Where the pipe upon which the threads are to be out has a limited projection fromits chuck or holder, as the greatest taper quickly embraces and removes the burr, while the smaller taper cuts the desired number of threads before coming in contact with the chuck or holder. In this respect it differs from asingle or uniform taper die, whose length has to be increased in proportion to the diameter of the burr on the end of the pipe or blank. By my improved form of cutti n g-thread I am also enabled to remove the excess of metal at the end of the pipe or blank with much less power, and when it is desirable to remove the pipe or screw from the cutterit is much sooner relieved from strain or pressure.

My improved. dies are preferably formed by first making them in a singlepiece and completing the double-taper thread, and then subsequently cutting the die apart, in contradistinction to the present process, which consists in forming the regular taper, and then reaming out to form the increased taper or flare, and without retapping.

What I claim as new, by Letters Patent, is-

l. A screw-cutting die having the initial or starting end enlarged, as described, and provided with a leading-thread, as and for the purposes set forth.

2. The die-plate G, made of a single piece, and having its ends extended at the four corners beyond the planes occupied by'the heads of the adjusting-screws to form lugs H, which shall serve to maintain the plate against movement when in a die-box, and at the same time guard the adjusting-screws against accidental movement, as hereinbefore set forth.

3. The die-boxB, adapted to enter the dierecess in the head of a pipe-cutting machine, and extended forward and laterally to form a receptacle for a die and die-plate, substantially as hereinbefore set forth.

Witness my hand and seal this 14th day of February, A. D. 187 9.

JOHN H. VINTQN.

In presence of-- Trrnononn Oounrrmenr, WILLIAM OMALLEY.

and desire to secure

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