Setscrew and method of producing same

April 22, 1941.

2,239,352

A. J. CHERRY

SETSCREW AND METHOD OF PRODUCING SAME

Filed Feb. 23, 1939

<img file="US2239352A_D0001.tif" />

«tented Apr. 22, 1941

2,239,352

Claims.

^{relates to a new} and improved °^{f maklng} ^screws and is here Illustrated as applied to the production of headless idanf Art ^S+ ^htL^ln? ^{sharp edge on its inner} end ?^da_t^pl!^{d t0} “^teJ^{nto and h}°^ld the screw In con?to£Spiled °^Γ °^{thei t0 Whlch the screw}„ ™^s ^ention also relates to the improved setrefXrtrt ^{ed aS a resuIt of the} P^rocess herein reierrea to.

,,. P^ne °! ^the ehjeets Of this invention is to provide an improved method by which setscrews of the above-described type may be made by the use of conventional thread-rolling machines having the usual type of thread rolling die blocks.

»Jirtrt ^partlcularly an object of this invention to provide, In combination with a thread-rolling oo^{a pre}“^minary step for treating the screw blank, whereby the blank is provided with an upper temporary flange which serves in the capacity of the usual screw head for holding the screw blank while it is being Operated upon by the conventional screw-rolling machine.

It is a further object of this invention to provide, as a part of the preliminary treatment of the blank, a depression in the lower or inner end thereof, whereby a sharp edge is provided by means of a subsequent screw-cutting operation performed during the rolling of the screw in the conventional screw-rolling machines.

It is a further object of this invention to provide a method which is greatly simplified and which will materially reduce the operations incident to the manufacture of such setscrews and, consequently, the manufacturing cost thereof.

It is a further object to provide an improved setscrew of good construction by an operation which produces a high degree of uniformity throughout all of the setscrews made, independently of how small or large such screws may be.

These and other objects not specifically enumerated are contemplated for this invention, as will readily appear to one skilled in the art as the following description proceeds.

The invention has been illustrated in the accompanying drawing, in which—

Figure i is a side elevational view of a conventional type of thread-rolling machine adapted for handling, threading and cutting the setscrews of this invention.

Figure 213 an enlarged cross sectional view of a suitable type of compound blank-forming die which serves to pre-form the blank for subsequent threading and cutting treatments in the machine shown in Figure 1.

UNITED STATES PATENT OFFICE

2439,352

SETSCREW AND METHOD OF PRODUCING SAMs' _:^CM.^^ag0,.ffl? assignor to EconraXno7^Sr^raU&lt;’^,1’^C11,Ca&lt;O’^IU-^acorpoApplication February 23,1939, Serial No. 257,802 (CL 10—19)

Figure 3 is an enlarged perspective view of a pair of die-threading blocks of the type utilized in the machine shown in Figure 1, together with a cutting Wade which engages and cuts the end of the setscrew during the thread-rolling operation. Inis cutting method and means is clearly described and claimed in the copending application of Andrew J. Cherry and Andrew J. Jaskowlak. Serial No. 234,096, filed October 10, 1938.

^{an elevational} view of the blank from which the setscrew of this invention is made.

Figure 5 is a view similar to Figure 4, partly in cross section, showing the modified blank after the first step of the forming operation has been completed by the dies of Figure 2.

J?*™ “^evational view, partly in cross ., section, of the setscrew after the next step of the treSii⁸, °Pe^ratlon an^d as it appears after it is 9n ^{treated in the} machine shown in Figures 1 and 3·

Figure 7 is an elevational view of the finished setscrew after it is pre-formed, threaded and cut provided wrth a tool-receiving slot, and hardened so as to be ready for use.

’ fh^BAi^eier5^{ing to the drawln}«. it is to be noted tt^at„^the,^setsc5^ew of this invention is made from a blank of metal 10, such as shown in Figure 4 which may be cut from a continuous length of wire or similar stock, or derived from any other convenient source. This wire may be cut and handled in the usual way common in the screw manufacturing industry.

As a second step in the screw-forming operation, the blank 10 is subjected to a die-forming operation by means of the die parts II, 12 and 13. The die part 11 is provided with a cavity 14 which receives the blank 10, whereas the die part 12 has a cavity 15 for receiving the upper ^epd °^f ψε ^{blank as} ft projects upwardly to a slight extent above the die part 11.

Die cavity 15 is so formed as to upset the upper end of the blank 10 to form a small head 20 thereon, as shown m Figure 5. This head 20 is provided with a shoulder 21 which sticks out laterally from the blank so as to form a holding means by which the blank may be carried through the normal thread-rolling machine. Above the shoulder, the head is provided with an inclined surface 22 which 5°, is preferably on substantially the same angle as the incline of the thread to be placed on the flnt«^eof th^rnh_n^^rth»r?^Ore’^{the maximum} diamennt.M»^hrt· ^{h der 2 18 substan}tially equal to the outside diameter of the threads of the finished :-5 setscrew, due to the fact that the thread-rolling

2,239,352 feeding of the screw blanks, as shown in Figure 5, down the incline 31 by means of the heads 20 and the holding shoulders 21 provided thereon. As the screw blanks present themselves at the bottom of the feeding slide 31, they are successively caused to pass between the threading blocks 32 and 33 in the conventional manner, so that upon reciprocation of th'e threading block 32 the blank is caused to be rolled between the 10 threading blocks and to be provided with a thread on its surface by means of the thread-forming action of the threads on the blocks.

According to this invention, the head 20 on the blank shown in Figure 5 is formed in extent and of such character as to correspond at least in part to the uppermost thread to be formed on the finished screw.. As a result, the blank is held with its upper surface substantially flush with the upper surfaces of the threading blocks 32, 33, respectively, whereby, upon the completion of the thread-rolling operation, the entire surface of the setscrew is subjected to the threadforming action of the threads on the die blocks, and the portion of the screw blank which originally constituted the temporary head 28 is rolled into and caused to become a part of the finished thread on the outside surface of the. screw.

Thus, it will be seen that the. threads of the setscrew are formed continuously all the way to the top edge of the screw without leaving any head thereon. By this novel procedure, the applicant provides a headless screw of the setscrew type while at the same time there is provided; for use during the thread-rolling operation, a temporary head which Serves to hold and feed the blanks through the various parts of the thread-rolling machine. This temporary head is ultimately disposed of during the thread-rolling operation because the head itself is formed of such character as to, in effect, constitute in part the finished thread and the remaining part thereof is immediately acted upon by the threadforming portions of the dies, whereby the same is rolled into and becomes a part of the finished ⁴³ screw thread.

Attention is now directed to the action of the cutting blade 66 which has a cutting portion 61 in engagement with the lower edge of the setscrew during the thread-rolling, operation. As will be clearly shown in Figure 6, the^λ cutting surface 6 ί of the blade 30 forms a beveled surface 79 adjacent the bottom or inner end of the setscrew, which is inclined sufficiently to interk rupt that portion of the bottom of the screw ⁰ blank in which has been formed the semi-circular depression 23. Where the beveled surface 79 meets the edge of the depression 23, there is formed a sharp circular edge designated 75 in Figure 6, which sharp edge automatically results from the action of the cutting blade cutting into the previously formed depression 23 in the bottom of the blank. .

Thus, when the thread-rolling operation is complete, the headless setscrew is not only provided with its threads in the desired manner, but it is also provided with a tapered bottom portion providing a sharp circular edge for biting ________ ______ into and exerting a holding action on a shaft or blank but at a sufficiently less rate to cause the other metallic part with which the setscrew is screw blank to push against the cutting edge 61 to an extent to cause the cutting edge to cut a beveled surface on the lower edge of the screw blank, in the manner shown in Figures 6 and 7.

Accordingly, this invention provides for the dies cause the metal to roll up and increase the finished diameter at the crest or ridge of the

The die part 13 is mounted for reciprocation in a cylindrical opening 16 and is provided with an upstanding dome-shaped portion 17 which forms a semi-spherical depression 23 in the bottom of the screw blank 10. This is clearly shown in Figures 5 and 6 of the drawing.

This initial treatment of the screw blank may : be accomplished in one or more operations of the dies. If accomplished in one operation, the blank may be quickly brought to the shape shown in Figure 5 by a single quick movement of the die parts.

After this initial treatment of the screw blanks, they are next placed in a suitable container, such as 30, of a conventional form of screw-threading machine employing thread-rolling die blocks so that the blanks, after being picked up by conventional pick-up mechanism, are fed in succession down an incline 31 in proper position to present themselves to the thread-rolling blocks 32, 33, respectively. It is not believed necessary to describe this type of machine in detail as the thread-rolling portions thereof are of conventional construction and the improved screw-cutting mechanism which is added thereto constitutes an improvement which is now set forth and claimed in the copending application of Andrew J. Cherry and Andrew J. Jaskowiak, Serial No. 234 096 filed October 10, 1938 (since issued as Patent No. 2,174,968, Oct. 3, 1939). However, it may be mentioned that this type of machine usually comprises a stationary threaded block 33 _c mounted by suitable clamps in an adjustable carrying base 34 capable of being adjusted by means of holding screws 35, 36, respectively. These parts are all held in a frame 40 which is provided with a pair of guide track members 4 i which hold a slide 42 adapted for reciprocatory movement forward and backward with respect to the stationary die block 33. The mechanism for causing such movement, however, is not here shown. The slide 42 serves as a mounting for a movable die block 32 held in position by suitable screws 43 and 44.

Mounted above the thread-rolling mechanism there Is a slide guide 50 which serves as a mounting for the dovetailed slide 51 which is also reciprocated in predetermined and timed relationship to the reciprocatory movements of the slide 42. This particular movement is effected by a cam and lever mechanism which is not here shown or described, but which constitutes the subject-matter of the copending application above referred to.

The upper slide 51 carries an adjustable knife blade 60 which extends downwardly between the threaded die blocks 32 and 33, respectively, in _$0the manner shown in Figure 3, and presents a cutting edge 61 adapted for engagement with the lower portion of the setscrew blank 10 being rolled between the threading blocks. The upper slide 5i is so adjusted and operated with relation ₆₅to the lower slide 42 and the movable threading block 32 that the blade 60 is caused, first, to come in contact with the screw blank being treated therein and then to travel with the screw to be associated.

Following this operation, the setscrew, by any conventional operation, may have a tool-receiving slot 76 placed in its upper end, as shown in 75 Figure 7, and thereafter it may be hardened or rp«X^Wf^{Se treated t0 brin}? Η to its final form ready for use.

. Τπθ ^shed screw which is shown in Figure 7 “ ^adaPte^{d t0} be inserted into a threaded open°^{f the} type usually provided in knobs or the ^h^¹^^{05 01 in similar} Parts, in order that ^{Parts may be flxed} to the asso^®?J^hafts °^{r the like}· ^{By the use} of a tool inserted in the slot 76, the setscrew may be ° ^{the opening un}til the bottom end thereof engages the metal or other part which fnrppfni^et^{held by the setscr}ew. Thereupon, a forceful turning of the setscrew will cause the ®^barp bottom edge 75 to bite into the metal or other part so as to securely fix and hold the setscrew in the desired manner,

The foregoing method should be considered in conjunction with the copending application a^b°ye referred to of Andrew J. Cherry and Andrew J. Jaskowiak, Serial No. 234,096 filed ?v74^b_Q^eJo ¹⁰’ ^{1938 (since} issued as Patent No 2 174,968, Oct. 3, 1939), in which is fully set forth the method and mechanism for operating the cutting blade 60 here referred to for forming the beveled edge 70 on the bottom of the setscrew. ^u^F/^om the foregoing it will be apparent that °^{d provldes a νβ1}Υ simple and yet highly efficient means and method for forming setscrews having many desirable features. It also provides an improved setscrew which is ^mad® by two major screw-forming operations which include, first, the initial die treatment for forming the temporary head and the depression m the bottom, and, second, the thread-roll^{lpg and} screw-cutting operation which is accom? ^S?i^{gle reci}P^r°cating action of the modified but otherwise conventional thread-rolling machine. The only remaining operation required is that of putting the tool-receiving slot in the top and of hardening the screw or otherwise finishing it in any desired manner.

The foregoing description and disclosure in the drawing is given merely by way of illustration and is not to be considered as limiting the invention in any respect, as the scope of this invention is to be determined solely from the terms of the appended claims.