US1642736A

US1642736A - Method of forming set screws

Info

Publication number: US1642736A
Application number: US107545A
Authority: US
Inventors: Charles E Lyman
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-05-08
Filing date: 1926-05-08
Publication date: 1927-09-20
Anticipated expiration: 1944-09-20

Description

Sept. 20,1927. 1,642,736

c. E. LYMAN METHOD 0F FORMING SET SCREWS Filed May 8. 1926 Patented Sept. 2D, 1927.

UNITED STATESA CHARLES E. LYHAN, F WATERBUB'Y, CONNECTICUT.

METHOD 0F FOBMING SET SCREWS.

Application led lay 8,

This invention relates to a method of making set screws of the type that have in their heads angular sockets which are adapted to receive a ke wrench for turning the screws into and ou of place.

The object of the invention is to prov1de a process by means of which such screws may be produced from cold slugs of metal very rapidly and cheaply, there being few o erations and no waste metal, and the metal o the slugs bein so flowed as to produce dee and accuratey sized and shaped sockets wit strong walls, thus ensuring a good fit for the wrench and eliminating danger of splitting or breaking the screws or wearing or stretching the sockets so that the wrench will not turn the screws wihen they are screwed into place tightly, or when it is desired to remove the screws after they have been in place for a long time and have become corroded.

In attaining this object a slu of cold metal of uniform diameter cut t e proper length from a rod or wire is fed into a die cavity of slightly larger diameter than the diameter of the slug, and while confined therein is subjected to percussive force in such manner that coincidently a conical cup is formed in one end and the other end extruded from the die\ cavity onto a punch which acts as a mandrel and about which the extruded metal flows to form the socket, the exterior ofthe slug about the socket during this action being given approximatel final shape and size by the contour of the wall at the mouth of the die cavity from which the metal is extruded. The cupped end of this blank thus produced is then bevelled and coincidently the socketed end is rounded, and nally a thread is cut or rolled on the exterior of the blank. By the practice of this process, without heating, strong and accurate grub set screws can be produced by three operationsor by three machines only.

The "blank forming step of this process may be taken by such tools as are described in my co-pending application #752,161, filed Nov. 25, 1924, although other tools can be employed, and those tools are especially'q adapted to be used in a solid die cold header of well known type, such as is set forth in United States patent to Campbell #569,406,

Oct. 13, 1896 although other heading machines could be used.l

In the accompanying drawing Fig. 1

1926. Serial No. 107,545.

shows a side view and a transverse section of a rod from which aeslug may be cut. Fig. 2 shows a side view and longitudinal section of the slug. Fig. 3 shows a side view and longitudinal section of the socketed and cupped blank produced from the slug by the first step of the process. Fig. 4 shows a side view and longitudinal section of the blank after it has been rounded and bevelled by the second step. Fig, 5 shows a side view and longitudinal section of the finished set screw, that is, the blank after a thread has been rolled or cut on its exterior. Fig. 6 shows a die, feed pin and punch, and thei:l supporting parts of a heading machine, nhich may be used in practicing this invention. Fig. 7 is a section of the die with a slug fed into it by a feed pin. Fig. 8 is a section showing the punch or mandrel advanced and about to act upon t-he slug in the die. Fig. 9 is a similar view showing the relation of the parts after the slug has been percussively acted upon to produce the cup at one end and the socket at the other en In the practice of this invention the slugs 1 can be cut from a rod 2 of uniform diameter fed into a Cold header in the usual manner, or they may be produced in another machine and fed individually into the header in the well known way.

In the views 3 indicates the forward end of a punch bed which is mounted on thev reciprocating ram of a header so that it may be raised and lowered for first presenting the feed pin 4 and then the punch 5 in line with the die 6, and also carried back and forth for feeding the slug into the die cavity and then for acting upon the slug in the cavity, as is well understood. The feed pin of the tools illustrated is mounted in a thimble 7 set into the punch bed, and is pressed forward by a spring 8. The punch is mounted in the punch block 9 set into the punch bed with its forward end supported and guided by a sliding sleeve 10 and its rear end abutting against a hardened backing plate 11. The forward end of the punch projects a slight distance beyond the front end ofthe unch block and its cross sectional shape 1s that which will produce the required cross sectional shape, preferably hexagonal, of the socket in the screw to be made.

The die is slidably fitted in a sleeve l2 that is secured in the front wall 13 of the frame of the header. The die cavity has a cross sectional sha e that will impart the exterior outline to t e screw blank to be produced, and the die is normally pressed forward by a spring 14. Projecting into the die cavity from the back is a pin 15 attached to the end of the knock-out plunger 16. The length of this,pin is'varied according to the length of the slug that is to be operated upon and it has a conical tip 17 which is desifrned to form a vcup in the bottom end of the slug.

With the parts in their normal positions and doing no work the die is pressed forward by its spring andthe tip of the pin is a short distance inside of the face of the die, while the forward end of the punch is slightly forward of the face of the punch block, as illustrated in Fig. 6. In the standard two-blow cold header for which the tools shown are especially designed the slug that is slightly smaller in diameter than the die cavity is fed inthe usual way and pushed into the die cavity by the feed pin that at this time is in line with the die. As this takes place the backing pin and knock-out plunger are forced back as illustrated in i 7. After the feed pin is withdrawn and raised and the punch brought into line with the die, the punch is driven forward. As the punch enters the die opening and engages the slugthe face of the punch block engages the face of the die and presses the die back. The die is forced back a distance equal to the distance the punch is driven into the slug, and as the slug is held by the backing pin the metal 18 displaced by the punch 1s extruded from the die cavity form- 1n around the punch as a mandrel. Fig. 9. with this action the surface of the wall 19 at the mouth of the die cavity which controls the exterior shape of the metal extruded is always the same.

With the slug confined in the die in this manner and backed by the conically tipped pin, the blow given by the punch produces the elongated b ank 20 of unlforln diameter, Fig. 3, with the hexagonal socket 21 at one end and the conical cup 22 at the other end. This step of the process may be performed by the well known heading machines, and it produces the required cupped blanks very rapidly and cheaply with accurate and well formed sockets and exact exterior diameter.

Theseblanks can then be fed to a common screw machine which is tooled to round off `the socketed end 23 and taper the cupped end 24, Fig. 4, which cutting operations may be performed coincidently, after which a tion opposite to the movement o-f the unch and die, and subsequently threadingt e exterior of the blank thus produced.

2. The method of forming socketed4 set screws which consists in feeding a cold meta-l slug of uniform diameter entirely within a cavity, holding the` inner end of the slug in a fixed position, 'forcing a punch of smaller diameter into the outer end of the slug thus confined and held and coincldently retreating the cavity a distance equal to the advance of the punch into the slug, whereby metal of the slug is caused to flow longitudinally out of the cavity and along'the punch, and threading the exterior of the blank thus produced.

3. The method of forming socketed set screws which consists in feeding a cold metal slug of uniform diameter entirely within a die cavity and while the slug 1s confined and `held stationary by percussive force exercised against the slug, coincidently forming a cup in the inner end of the slug and causing the outer end of the slu to elongate and extrude from and be shaped by the mouth of the dier cavity, in a direction opposite to the application of said force and produce a socket in said elongated end,

and threading the exterior of the blank4 thus produced. .n

4. The method of forming socketed set screws which consists in feeding a cold metal slug of uniform diameter entirely within a die cavity and while the slug is confined and held stationary by percussive force applied to the slug simultaneously cupping the inner end of the slug and causing metal of the outer end of the slug to ex- Atru-de out of and be shaped by the Imouth of the die cavity onto the means for applying, and in a direction op osite to the application of, said force andp in, subsequently bevelling the cupped end, rounding the elongated end, andthreadin the outer surface of the blank thus forme.

CHARLES E. LYMAN.`

form a socket there-