US2838317A

US2838317A - Feed collet

Info

Publication number: US2838317A
Application number: US390970A
Authority: US
Inventors: Albert A Parigian
Original assignee: Modern Collet & Machine Co
Current assignee: Modern Collet & Machine Co
Priority date: 1953-11-09
Filing date: 1953-11-09
Publication date: 1958-06-10
Anticipated expiration: 1975-06-10

Description

June 10, 1958 A. A. PARIGIAN FEED comm Filed Nov. '9, 1953 IN VEN TOR. A/berfA. Par/glam United States Pate t p FEED COLLET Albert A. Parigian, Allen Park, Micht; assig'nor to Modern Collet & Machine Co., Ecorse, Mich., a corporation of Michigan Application November 9,1953, Serial No. 390,970

* 1 Claim. (Cl.':279-46) This invention relates to feed collets of the type employed in connection with automatic machines for successively feeding lengths of stock relative to suitable tools. s, M

Feed collets of the above general/type usually comprise a tubular body longitudinallyj'slotted at circumferentially spaced points intermediate the ends and at one end to provide axiallyspaced sets of stock gripping fingers. The intended purpose of the'fingers at one end of the body is to continue the gripping action on the stock after the latter is fed beyond the intermediate fingers so that a' greater length of the stock maybe used. However after continued use of the collet the gripping fingers wear to such an extent that they no'longer grip the stock with sufficient pressure to advance the stock and it becomes necessary to deform the fingers in an inward di rection to restore the the fingers by the application of a contracting pressure thereon causes the fingers to in eifect fulcrum about their connections with the body of the collet and the structure is such that while the clamping action is somewhat increased, nevertheless, the area of contact of the fingers with the stock is decreased. As a result, the unit pressure applied to the fingers is increased and the rate of wear of the clamping surfaces of the fingers is correspondingly increased. In fact the gripping surface area of the fingers at one end of the collet body becomes in effect a line contact after inward deformation of these fingers and in many instances is insufiicient to feed the stock after the latter is released by the intermediate fingers.

With the above in view it is an object of this invention to overcome the above objections by providing a collet body with stock gripping fingers of a nature to assure an extended area of contact with the stock throughout the full range .of inward adjustment of the fingers relative to the collet body. Thus, feeding of a length of stock is assured by either the intermediate and/or the end fingers regardless of the extent of wear of the latter so that the effective life of the collet feeder is appreciably increased.

The foregoing as well as other objects will be made more apparent as this description proceeds especially when considered in connection, with the accompanying drawing wherein:

Figure 1 is a side elevational view of a feed collet constructed in accordance with this invention;

Figure 2 is a longitudinal collet shown in Figure 1;

Figure 3 is a cross sectional 33 of Figure 1; and

Figure 4 is a cross sectional view taken on the line 4--4 of Figure 1.

The feed collet shown in the drawing comprises a tubular body member preferably formed of steel having a continuous annular portion 11 at the rear end externally threaded as at 12 for attachment to a feeding element,

view taken on the line clamping action. Deformation of sectional view through the annular portion 13.

bad continuous annular portion 13 spaced 2,838,317 Patented June 10, 19 58 not shown. The tubular body member '10 has a secaxially forwardly from the annular portion 11 andhaving an external diameter approximating the external diameter of the annular portion '11. The internal diameter of both annular portions 11 and 13 is suflicient to provide ample clearance for the passage of a length of stock therethrough. I

The portion 14 of the collet body between the annular portions 11 and 13 is formed with circumferentially spaced longitudinally extending slots from one annular portion to the other. The slots 15 also extend radially with respect to the axis of the tubular body member 10 and divide the intermediate portion 14 'into bars 16 of wedge shape cross section. In manufacture the intermediate portion 14 is contracted relative to the continuous annular portions and the bars 16 form stock gripping fingers 17. The inner surfaces of the fingers .17 I cooperate tion 18 having an internal diameter sufliciently less than the external diameter of a length of stock to frictionally grip the latter. It is apparent from Figures 1 and 2 of the drawings that the intermediate sections of the fingers body member for a substantial distance in order to pro- -vide extended bearing surfaces for engagement with a length of stock. I fiare outwardly and are integrally joined to the respec- The opposite ends of the fingers 17 tive annular portions'lland 13 n v It follows from the foregoing that a stock bar is frie-' tionally engaged by the fingers 17 for a substantial part of the length of the latter so that forward movement of the collet imparts a corresponding movement to the stock bar. During the succeeding rearward movement of the collet, the fingers 17 slide rearwardly relative to the stock bar and hence the stock engaging surfaces of the fingers 17 eventually wear to a point where the stock is no longer gripped thereby. This condition is rectified by applying the sufficient external pressure to the intermediate straight sections of the fingers 17 to deform the same to the extent required to compensate for the wear of the gripping surfaces. Although the length of the stock engaging surfaces on the fingers 17 is somewhat reduced following each adjustment or inward deformation of the fingers, nevertheless, the original length of these surfaces is such as to afford ample gripping action to feed the stock throughout the full range of adjustment of the fingers. Thus the life of feed collets having fingers of a given thickness is greatly increased.

In order to continue feeding of the stock after the latter is advanced beyond the fingers 17, a second set of gripping fingers 19 are provided on the front end of the tubular member 10. The fingers 19 are produced by forming circumferentially spaced longitudinally extending slots 20 in the tubular body member in advance of the The slots 20 extend forwardly from the annular portion 13 to the front end of the tubular body member 10 and the resulting fingers 19 are contracted to provide a gripping portion 21 having an internal diameter approximately internal diameter of the gripping portion 18 formed by the fingers 17.

The fingers 19 are flared outwardly and are integrally joined to the annular portion 13 in a mannerio permit deforming the free end portions of the fingers 19 inwardly to reduce the effective internal diameter of the gripping portion 21 and thereby compensate for wear of the work engaging surfaces of the fingers 19. The inner surfaces of the fingers 19 available for engagementwith a length of stock are elongated in the direction of the axis of the tubular member 10 and extend parallel to the latter axis. The axial length of these surfaces is such that the fingers 19 maintain an extended area of 15 which extend V to provide a gripping 'por-' gripping contact with the stock' throughout the full available adjustment or'inward deformation of' the'fingers' 19:

Thus, proper feeding of the work solely by the fingers 19 is assured throughout the life of the feed collet or SQ long, asthe' thickness of the fingers 19remains1suf ficient to gripthe WOIk.

What I Claim as my invention is: g p

A feed collet comprising a tubular member having first and second axially spaced circumferentiallycom tinuous annular portions, circumferentially fingers at one end'ofsaid tubularmember, said'fingers projecting generally axiallyv of said tubular member from said first annular portion in a direction away ifronrsaid second annular portion, said fingers having p ortionsintegrally joined to" said first'annular' portion inclined from.

said first annularportion radially inwardly of said tubular member and having. gripping portions integral with and in continuation'of saidin'clined portions extending in substantially parallel relationship to. the axis of said tubular member for a considerable distance to'the' free ends of said'fingers, said inclined portions providing flexing sections enabling adjustment of said fingers radially relative to said first annular portion, the axial elements of the internal stock engaging sur'fa'ce'of the gripping portion of each finger extending for the full length of said gripping portion along the axis of said tubular member in parallel relation theretoto provide an'extended bearing engagement withth'e stock in the various adjusted positions of said fingers, said tubular member having a reduced portion between said annular portions formed at circumferentially spaced points'with longitudinally ex tending slots closed at the ends'to' provide a plurality of elongated circumferentially spaced generally axially, ex-

spaced' feed tending feed fingers respectively axially aligned with said first=mentioned-feed-fingers; said last-named fingers having intermediate portions ofconsiderable length extending substantially parallel to the axis of said tubular member, the opposite ends of said last-named fingers flaring radially outwardly from said intermediate portions and being integrally connected to said annular portions to provide flexing sections enabling radial adjustment of said last-named fingers, the axial elements of the internal stock-engaging surface of the intermediate portion of each of said last-namedfingers extending for the full length of said intermediate portion along the axis of said tubular member and in parallel relationship thereto to provide an extended bearing engagement with the stock in the various adjusted positions of said last-narned fingers.

References Cited in the file of this patent UNITED STATES PATENTS 1,433,890 Johnson et al. Oct. 31, 1922 1,538,442 Mann May 19, 1925 1,597,404 Crossley Aug. 24, 1926 1,608,627 Shelter Nov. 30, 1926 1,957,235 Simpson 1 a May 1, 1934 2,037,304 Baxendale Apr. 14,1936 2,221,734 Evans Nov. 12, 1940 2,228,863 Wright Jan. 14, 1941 7 2,341,744 .Shefier Feb. 15,1944 2,521,099 Shelfer Sept. 5, 1950 2,680,623 Hasselblad et al. June 8, 1954 FOREIGN PATENTS 709,553 Germany Aug. 20, 1941