US2568439A - Method and apparatus for making screws and the like - Google Patents

Description

Sept. 18, 1951 J, FRIEDMAN 2,568,439

METHOD AND APPARATUS FOR MAKING SCREWS AND THE LIKE Filed April 27, 1945 7 f m I8 1 I9 25 ag 26 2/ 55 14 /2 ,8 Z I7 I 5 T )6 l4 INVENTOR. 58 JOHN H. FRIEDMAN ATTORNEYS Patented Sept. 18, 1951 corporation .ofnOhio Ap lication p -.11 2.7, 1945; [s rial Nq; 03556;

My invention relates; to headers; and particularlyheadrtoolsforfforming -recessed'heads.

Header tbols=- for punching rece'sses into; me

heads-iofi-articles; and for-similar duties; are fre-' quenu-y subjected to laterarbending stresses when tend? tobreak the'hardened tool steel or othr material from which the tools areiormed. Any non 'uiii'formity in the distribution or physical properties {of the material being punched telifds to deflectthe point of; the tool away from it's true axial direction after it has entered the material; Inacouraciesiri' the shapeof the tool, and play of-the header slide in its bearings havej similar-tendencies: The tool'must be rigidly supported by theheader slide inorder' that the point will enter the material to be punchedgsothatin the usual constructions any defieetion ofthe tool afteritiha's' enteredthe material applies'a bendmg force to the relatively, brittle tool. 7

Theprincipal" object of this invention is to eliminate; the breaking of" header toolsfrom this cause. Other objectsjare to rigidly support and center'a toolatthe time it'first, en a es the work piece and to" free the tool-for slightlateralmove ments during. the remainder of theworking strgke afterthetocl has become gpiddj by' the wo'rl; niec to, relieve,possible inacpu iacy of; previous needing; operatirinSi, andtq relieve or allow for lack o'fsymmetry in; tools in" blanks, or in the composition of the material of whichlthje wank is composed.

V Other" and further objects} features and ad vantages ofthe invention willj become apparent as the] de ription proceeds;

better: understanding: ofgth'e invention will be afforded by the follqwingfdetailed' description consideredin conjunctionwith the accompanying drawing and the scope of the invention willbeiset forthinxthe claims;

n h a es: v V

Eigj l'is; a longitudinal sectional *view oreschematically indicated apparatus representing the action of,the, first blow of a3 double-blow header fdi jfiojrming a screw with amas edhea Fig; 2 iseqqngituqihaisectional view ofteat} p'aratusjemployedin the secbn'dblow of adouble blow 'lieader in accordance" with an embodiment of my invention showing th initial step m piercing-the head of the blank Fig? 3 is a view cdrresponding to Figfl-z repre senting a moreafd'vanced step in theprocess;

Eiil i'sfa view-1 correspdnding to Figs; 2- and 3 showing the relative positions of parts upon the e m ie'ntn of the recess in thehead of the blank? and Fig 5= is aperspective view of a'blank withthe, recessed head: completed;

Like/reference characters: arecused throughout; the drawing to-designate like'parts.

5 In carrying out 'myeinvention in:itspreierred form-for producing vrecessed screw heads, -I utiliz'e a eonventional double blow header; Different tools are utilized in the first and second blowsof the header. In thefirstblow a blank nonrecessed head is formedin the conventional manner. In the. second-1 blow the r headi: is pierced with a suitable toolvproducingie for? eXJ-L ample, the four-winged socket or recesscharacteristicofiPhillips screws? A-' conventionahtype of piercing'tool maybe employed. However;-the

tool is provided with a special mounting 5 which initially centers the tdol with respect to the :blank head, but allows the tool to drift'laterallmaften a predetermined relativeilongitudinal motion has taken place between the die carrying. the blank head and the piercing tool. Tolthisg end z-la, tapered=or frusto-conicalrwedge maybe employed initially urged: outward" toarigidly' center the tool;- whie'h is loosened topermit lateralwmotionhf the tool as the header and die cometogether.

Referring to' Fig. 1 of the drawing, for thetfirst blow l of' the header: a. blank" N is held: within a; suitable die I2 mounted in "a bed frame (not shown) and a conventionali heading tool l3vis 3 0 provided forforming a blank'headil 4'- on the end of thewirestock I IL The die 12' is provided with the usuar knockout rod I 6, which may also serve to backup theblank during theheading blowi For carryingout the second and final operation on head marine blank H, apiercing-tool I1: is

provided as" illustrated in Figs. 2, 3" and As in conventional double-blow headers, a tool carrier l tl'is mounted upon a reciprocating header slide, and-"c arries indifferent positions the header tool 40 1-3 and a suitable mountmerqr thefinal header presentinventionmay beused.; 1t is;-o:rcourse-, m

be understood'thlat the present invention may alsb beused uponother double -blow headers; For supporting the;tool;*l;'l a mounting isprovided' comprising a chuck or wedge- 2 ll supported within a sqcketjm'einber 2 2 having'fa ape-semen .die l2. header slide 8 and the die |2 together. Initially the spring 3| holds the chuck 2| outward with its ner opening. A cylindrical cavity 23 may be provided in the portion I9 of the tool carrier I8 to receive the mounting members 2| and 22. The chuck 2| has a substantially cylindrical bore 24 within which the tool I1 is adapted to fit loosely to permit relative longitudinal motion of the tool I! and the chuck 2|. The tool I! is so arranged that its backward motion or motion toward the bottom of the socket or cavity in the tool carrier |B is limited. An anvil 25 is provided for this purpose. Preferably means are provided for limiting outward motion of the tool H with a little lost motion and for causing the extraction of the piercer 33 to begin before the chuck 2| has moved out far enough on the extraction stroke to restore realignment. To accomplishthis, annular grooves 26a and 26b are formed in the anvil 25 and the tool respectively, and a longitudinal split thimble 260 is provided, which engages the grooves 26a and 26b to limit the separation between the anvil 25 and the tool IT to the amount represented by the space 26d in Fig. 1. The chuck 2| has an increased diameter around the thimble 260' with a shoulder 26 suiiiciently near the outer end of the chuck to permit the chuck to recede the required, distance into the socket member 22.

The chuck 2| has an outer surface tapering to a smaller diameter toward the end, and the socket member 22 has an inner surface 28 tapering to a smaller diameter at the open end of the socket. The surfaces 21 and 28 are adapted to fit one another and if desired, the surfaces may form portions of a conical surface to produce frustoconical members. I Suitable means are provided'for securing the socket member 22 in the cavity 23. For example, a set screw 29 may be provided. Means are provided for normally holding the chuck 2| outward with its outer'surface 21 wedged tightly against the inner surface 28 of the socket member 22 for the purpose .of centering the tool |1 initially. For this purpose, resilient means such as a compression spring 3| may be employed.

The working edges of the piercing tool I! may head. The tip 33 is formed in a portion of a spherical socket 35 at the end of a substantially cylindrical bar or shank forming the tool 1.

In forming recessed screw blanks from wire or rod stock, a suitable blank is first cut off in the cut-oil station of the apparatus (not shown) and thereafter the blank H is transferred to the die l2. The tool carrier |8 is moved to such a position that the header tool |3 comes opposite the die |2 whereupon the numbers l2 and I3 are driven toward each other so as to form the head l4. It will be understood that the blank H is at the time located by the knockoutrod |6.

Thereafter the tool carrier I8 is moved to such a position that the mounting members 2| and 22 and the piercing tool I! are brought opposite the Then power is applied for bringing the frusto-conical surface 21 tight against the frustoconical inner surface 28 of the socket member, to center the piercing tip 33 of the header tool The first acis unloaded the instant ejection starts.

head l4 approximately at the center thereof, the exactness of the center depending upon the accuracy of alignment of the tool parts, the'wear thereof, and the accuracy with which the head H was formed by the header tool |3. Further relative motion between the header slide I8 and the die I 2 causes the vanes 34 of piercing tip 33 to sink more deeply into the head l4. However, there may be a tendency for the piercing tool to drift bodily if there is any inaccuracy in the initial centering or in the mounting of the parts, or if there is any lack of uniformity of the hardness of the metal'in the blank I or other lack of concentricity. To prevent such tendency for drifting from applying a bending force to the tool, the chuck 2| is so mounted that it may be freed laterally to a limited extent as it is moved in longitudinally.

After the tip 34 has sunk into the head l4 suffi-ciently to start and guide the tool, the outer surface or end 36 of the chuck 2| comes into engagement with the surface 31 of the die I 2, whereby the chuck 2| is caused to be moved inward relative to the socket member 22 against the force of the compression spring 3|. This action is illustrated by the position of the parts in Fig. 3 with the part of the die |2 at its surface 31 in engagement with the end portion or part 36 of the chuck 2|. As further motion takes place, the tool sinks more deeply into the head M. The chuck 2|, having moved inward, is freed from tight engagement with the inner socket surface 28 so as to permit limited lateral movement there of, thus allowing the tool to drift slightly in one direction or the other.

The tool I! is supported within the chuck2| which, in turn, is prevented from leaving the cavity 23' by reason of the tapering confronting surfaces 21 and 28. After the recess 38 has been formed in the head M of the blank II, the header slide I8 and the die l2 are moved apart, thus withdrawing the piercing tip 33 from the head M of the blank The latter may be ejected by the rod l6.

Upon the extraction stroke, the piercer tool H The thimble 26c ties the piercer tool I! to the anvil 25 but owing to the lost motion provided, the space 26d opens after dead-center and unloads the piercer tool just an instant before extraction begins. Furthermore the work is separated from the piercer tip 33 before the chuck 2| has reached its outermost position in which the parts again become rigidly aligned. In this manner any possibility of damage to the tool or the work during extraction is avoided in case of misalign ment.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be under-,- stood that I do not limit my invention thereto since various modifications thereof will suggest themselves to those skilled in the art. without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

What is claimed is:

1. In a header, a pair of relatively reciprocable members, a tool carried by'one of said members having a working portion adapted to engage a work piece supported by the other of said members, and movable means arranged to hold said tool against lateral movement with respect to said one member, one of said elements having associated therewith means operated in against lateral movement, causing endwis'e en gagement of the work-piece and the tool, increasing the force acting between the tool and thework-piece to form the latter, and simultaneously relieving the lateral support of the free end of the tool to provide for limited bodily motion of the end of the piercing tool to one side of its neutral axis.

11. In a header, a pair of members carrying limited lateral motion, said alignment means in-' cluding abutment means for engagement with the other of said pair of members to move said alignment means from its tool aligning position to said other position wherein the associated tool is freed for limited lateral motion.

12. In a header, a pair of members carrying cooperating tools, said members being movable axially toward and away from each other, alignment means movably mounted on one of said members, said alignment means in one position engaging and axially aligning the associated tool, said alignment means being movable to another position wherein it frees the asociated tool for limited lateral motion, said alignment means including abutment means, means on said header for engagement with said abutment means to move said alignment means from its tool aligning position to said other position wherein the associated tool is freed for limited lateral motion.

13. In a header, a pair of members carrying cooperating tools, said members being movable axially toward and away from each other, a chuck movably mounted on one of said members, said chuck surrounding the associated tool, said chuck having a wedge surface which in one position axially aligns the associated tool, said chuck being axially movable to another position wherein it frees the associated tool for limited lateral motion, said chuck including abutment means for engagement with the other of said pair of members to move said chuck axially from its tool aligning position to said other position wherein the associated tool is freed for limited lateral motion.

14. In combination, tool and die elements, said elements being relatively reciprocably mounted, said tool element having a mounting comprising a tapered socket with an open end of smaller diameter, a punch within and spaced from said socket, a chuck within said socket fitting said tapered socket and having a bore for receiving said punch, said chuck having axially sliding movement relative to said tool and said socket, means for resiliently urging said chuck toward the open end of said socket for intially centering the punch, means for holding said punch against axial motion relative to said mounting when said die and tool elements are brought toward each other with the punch engaging a blank to be worked upon in said die element, and means for engaging said chuck and moving it axially inwardly in its socket and relative to said punch when said die and tool elements are further brought toward each other for deformation of the blank by said punch, thereby freeing said punch for limited lateral motion in said socket.

15. In a header, a pair of members carrying cooperating tools, said members being movable 8 axiallytoward and away from each other, wedge means carried by one of said members holding the tool carried thereby against lateral movement with respect to its supporting member, one of said tools being arranged to restrain a length of stock against free axial motion and the other of said tools being formed to deform said stock, interengaging means between the wedged tool and its associated member to hold the tool against axial motion relative to said member during deformation of said stock, relative motion of said members toward each other to deform said stock causing engagement of said wedge means by the other of said members and axial motion of said wedge means relative to said one member andv the associated tool to release the tool restrained by said wedge means for limited lateral movement.

16. In a header, a pair of relatively movable work-holding and Work-engaging members, a recess formed in one of said members, a tool positioned in the recess of said one member having a working portion adapted to engage a work piece, movable Wedge means in the recess of said one member for holding said tool against lateral movement in the recess of said one member, said wedge means being movable relative to said one member as well as to said tool, resilient means urging said wedge means into position for firm engagement with both said tool and the wall of said recess for preventing lateral movement of said tool in said recess, the other of said members including means for moving said wedge means relative to the wall of said recess and to said tool to release said tool for lateral movement relative to said one member when said members are brought together to deform stock held by said work-holding member. 7

1'7. In a header, a pair of relatively movable work-holding and work-engaging members, a recess formed in one of said members, a tool positioned in the recess of said one member with one end projecting therefrom and having a working portion adapted to engage a work piece, the other end of said tool being formed for abutting said work-engaging member for the direct transmission of axial forces from said latter member to the working portion of the tool, movable wedge means carried by said work-engaging member holding, said tool against lateral movement in the recess of the latter member, said Wedge means being movable relative to said one member as well as to said tool, resilient means urging said wedge means into position for preventing lateral movement of said tool in said recess, said workholding member including means for moving said wedge means relative to the wall of said recess and to said tool to release said tool for lateral movement relative to said work-engaging member when said members are brought together to deform stock held by said work-holding member.

JOHN H. FRIEDMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 353,189 White Nov. 23, 1886 353,192 White Nov. 23, 1886 956,298 Cudahy Apr. 26, 1910 1,021,736 Glover et al Mar. 26, 1912 1,297,429 Wilcox Mar. 18, 1919 1,640,964 Schlaupitz et a1. Aug. 30, 1927 2,082,085 Tomalis June 1, 1937

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