US 2239352 A
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Description (OCR text may contain errors)
A. J. CHERRY SBTSCREW AND METHOD OF raonucma SAME April 22, 1941.
Filed Feb. 23, 1939 INVENTOR. (ifzdea/ L/Y/wr ATTO EY.S
iihiented Apr. 1941 2.239.352 sarscaaw m mgrrnon or raonucmo Andrew). ca
om! Screw n n rationof Illinois 111., aislgnor to Econtlon, Chicago,'nl., a com- Application February 2:. 1939, Serial Nb. 257,802
This invention relates to a new and improved method of making setscrews and is here illustrated as applied to the production of headless setscrews having a sharp edge on its inner end adapted to bite into and hold the screw in con tact with a shaft or otherD-rt to which the screw is to be applied.
This invention also relates to the improved setscrew produced as a result of the process herein referred to;
One of the objects of this invention to provide an improved method by which setscrews of the above describjed type may be made by the use of conventional thread-rolling machines having the usual type oi thread rolling die blocks.
It is particularly an object oithis invention to provide, in combination with a thread -rolling operation, a preliminary step for treating the screw blank, whereby the blank is provided with an upper temporary flange which serves in the capecity 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 inventionto 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 proride a method which is greatly simplified and which will materially reduce the operations in= cident 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. v
The invention has been illustrated in the aceompanying drawing, in which- Figure l 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 2 is an enlarged cross sectional view ofa suitable type of compound blank-forming die which serves to pre-forni the blank for subsequent threading and cutting treatments in the machine shown in S end of the blank as it 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 blade which engages and cuts the end of the setscrew during the thread rolling operation. This cuttingmethod 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.
Figure 4 is 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.
Figure 6 is an elevational view, partly in cross section, of the setscrew after the next step of the forming operation and as it appears after it is treated in the machine shown in Figures 1 and 3; and
Figure 7 is an elevational view of the finished setscrew after it is pre-formed; threaded and cut, provided with a tool-receiving slot, and hardened so as to be ready for use.
. By referring to the drawing, it is to be noted that the setscrew of this invention is made from a blank 01' metal it, such as shown in Figure 4, which may be out 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 operation by means of the die pa'rts ll, I2 and IS. The die part H is provided with a cavity H which receives the blank ID, whereas the die part I! has a cavity I 5 for receiving the upper projects upwardly to a slight extent above thedie part H.
The cavity i5 is so formed as to upset the upper end of the blank Hi to form a small head 20 thereon, as shown in Figure 5. This head 20 is provided with a shoulder 2| 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 is preferably on substantially the same angle as the'incline of the thread to be placed on the finished screw. Furthermore, the maximum diameter of the shoulder 2| is substantially equal to the outside diameter of the threads of the finished sctscrew, due to the fact that the thread-rolling a die-forming dies cause the metal to roll up and increase the finished diameter at the crest or ridge of the threads.
The die, part I3 is mounted for reciprocation in a cylindrical opening i6 and is provided with be accomplished in one or more operations of the dies. If accomplished in oneoperation, the blank may be quickly brought to the shape shown in Figure by a single quick movement of the die parts. 7
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 threadrolling 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 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! 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 inposition 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 5| 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. r
The upper slide 55 carries an adjustable knife blade 60 which extends downwardly between the threaded die blocks 32 and 33, respectively, in the manner shown in Figure 3, and presents a cutting edge Bl adapted for engagement with the lower portion of the setscrew blank It being rolled between the threading blocks. The upper slide 5| is so adjusted and operated with relation to the lower slide 42 and the movable threading block 32 that the blade 61) is caused, first, to come in contact with the screw blank being treated therein and .then to travel with the screw blank but at a sufliciently less rate to cause the screw blankto push against the cutting edge 8| 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 feeding of the screw blanks, as shown in Figure 5, down the incline 3| by means of the heads 20 and the holding shoulders 2| provided thereon. As the screw blanks present themselves at the bottom of the feeding slide 8|, they are successively caused to pass between the threading blocks 32 and 33 in thel'convjentional manner, so that upon reciprocation 'of'the' threading block 32 the blank is caused to be rolled between the 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 finishedscrem. 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-,theicompletion of the thread-rolling operation, the entire surface of the setscrew is subjected to the threadforming action of the threads on thedie blocks, and the portion of the screw blank which originally constituted the temporary head 29 is rolled into and caused to become a partaof the finished thread on the outside surface of the screw.
Thus, it will be seen that the,th, '68ds,of the setscrew are formed continuously all the way to the top edge of thescrew withoutieaving any head thereon. By thisnovel procedure, the ap plicant provides a headless screw of the setscr'ew type while at the same time there isprovided; for use during the thread-rolling operationjia temporary head which servesto hold and feed the blanks through the various parts of'the thread-rolling machine. I This temporary head is ultimately disposed of during the'thread-rollin 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 screw thread. 1 r r Attention isnow directed to the action'ot the cutting blade 60 which has 'a: cutting portion Bl in engagement with the-lower edge of the set"- screw during the thread-rolling. operation; As will be clearly shown in Figure 6', 'the cutting surface iii of the blade 50 forms a, beveled sur-fl face adjacent the bottom or inner end of the setscrew, which is inclined 'sufiiciently to interrupt that portion of the bottom of the screw blank in which has been formed the semi-circular depression ,23. Where the beveled surface Ill meets the edge of the depression 23, there is formed a sharp circular edge designated 15 in Figure 6, which sharp edge automatically re sults from the action of the cutting blade cutting into the previously formed depression 23 in the bottom of the blank; H
Thus, when the thread-rolling operation is complete, the headless setscrew is, not only p'ro-v vided with its threads in the desired manner, but it is also provided with a tapered bottomportion providing a sharp circular edge for biting into and exerting a holding action on ya shaft or other metallic part with which the setscrew' is to be associated.-
Following this operatiomthe setscrew, by any conventional operation, may have a tool-receiving slot 16 placed in its upper end, as shownfin Figure 7, and thereafter it may be hardened or otherwise treated to bring it to its final form ready for use.
The finished screw which is shown in Figure 7 is adapted to be inserted into a threaded opening of the type usually provided in knobs or the like for radios or in similar parts, in order that such knobs or parts may be fixed to the associated shafts or the like. By the use of a tool inserted in the slot 76, the setscrew may be turned into the opening until the bottom end thereof engages the metal or other part which is to be held by the setscrew.' Thereupon, a forceful turning of the setscrew will cause the sharp bottom edge 15 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 above referred to of Andrew J. Cherry and Andrew J. Jas'kowiak, Serial No. 234,096, filed October 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 won the bottom of the setscrew.
From theforegoing it will be apparent that this method provides a very simple and yet highly efiicient means and method for forming setscrews having many desirable features. It also provides an improved setscrew which is made by two major screw-forming operations which include, first, the initial die treatment for forming the temporary head and the depression in the bottom, and, second, the thread-rolling and screw-cutting operation which is accomplished by a single reciprocating action, of the modified but otherwise conventional thread-rolL ing machine. The only remaining operation required is that of putting the tool-receiving slot in the top and of hardening the screw or otherwisefinishing' 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.
What is claimed is:
1. The method of making screws, which com- I prises forming a temporary head on a screw blank, utilizing said head for feeding the screw blank to thread-rolling dies, rolling a thread on said-blank by means of said dies, and simultaneously rolling out said head so as to provide a headless threaded screw.
2. The method of making screws, which comprises forming a temporary head on a screw blank of size and shape approximating one thread of the series of threads to.be placed thereon, utilizing said head for feeding the screw blank to thread-rolling dies, rolling a thread on said screw blank, and simultaneously rolling out said head so as to provide a headless threaded screw.
3. The method of making screws, which comprises forming a temporary head on a screw blank, utilizing said head for feeding the screw blank to thread-rolling dies, rolling a thread on said blank by means of said dies, and simultaneously rolling said head so as to form the same into a portion of said thread.
4. The method of making screws, which comprises forming a temporary head on a screw blank of size and shape approximating one thread of the series of threads to be placed thereon, utilizing said head for feeding the screw blank to thread-rolling dies, rolling a thread on said screw blank, and simultaneously rolling said head so as to form the same into a portion of said thread.
5. The method of making screws, which comprises starnping a temporary head on a screw blank of size and shape approximating one thread of the series of threads to be placed thereon, forming a depression in the opposite end of said blank, utilizing said head for feeding said blank to thread-rolling dies, rolling a thread on said blank, and simultaneously rolling said head so as to form the same into a portion of said thread.
6. The method of making screws, which comprises stamping a temporary head on a screw blank of size and shape approximating one thread of the'series of threads to be placed thereon, simultaneously stamping a depression in the opposite end of said blank, utilizing said head for feeding said blank to thread-rolling dies, rolling a thread on said blank, and simultaneously rolling said head so as to form the same into a portion of the thread.
7. The method of making screws, which comprises stamping a temporary head on a screw blank of size and shape approximating one thread of the series of threads to be placed thereon, forming a depression in the opposite end of said blank, utilizing said head for feeding said blank to thread-rolling dies, rolling a thread on said blank, simultaneously rolling said head so as to form the same into a portion of said thread, and cutting the end of said screw blank to form a sharp edge thereon surrounding said depression.
8. The method of making screws, which comprises stamping a temporary head on a screw blank of size and shape approximating one thread of the series of threads to be placed thereon, forming a depression in the opposite end of said blank, utilizing said head for feeding said blank to thread-rolling dies, rolling a thread on said blank, simultaneously rolling said head so as to form the same into a portion of said thread, and cutting the end of said blank during the thread-rolling operation to form a sharp edge thereon surrounding the depression.
ANDREW J. CHERRY.