US2741023A - Method of making slit pins having continuously bevelled ends - Google Patents

Description

A. RAFTER April 10, 1956 METHOD OF MAKING SLIT PINS HAVING CONTINUOUSLY BEVELLED ENDS 2 Sheets-Sheet 1 Filed Sept. v2'7, 1952 IN V EN TOR.

ATTORNEY April 10, 1956 A. RAFTER 2,741,023

METHOD OF MAKING SLIT PINS HAVING CONTINUOUSLY BEVELLED ENDS Filed Sepi. 27, 1952 2 Sheets-Sheet 2 J INVENTOR.

than

United States Patent METHOD OF MAKING SLIT PINS HAVING CONTINUOUSLY BEVELLED ENDS Albert Rafter, Glen Ridge, N. J., assignor, by mesne assignments, toStandard Pressed Steel Co., Jenkintown, Pa., a corporation of Pennsylvania This invention relates to the art of making longitudinally slit pins which are used in many industrial and other applicationsfor example, as bearings in hinges and other apertured parts, as shown, for example, in German Patent No. 510,788, of October 28, 1930. Tubes with tapered ends to facilitate their insertion into apertures are shown in patents such as Patent No. 1,889,324 of November 29, 1932. Other patents in the art--for example, U. S. Patent No; 653,900-show the idea of forming continuous rings from initially fiat strips of material grooved in fiat form and then forced into circular form.

However, methods heretofore proposed for the forming of longitudinally slit tubes with bevelled ends from flat stock material have been cumbersome and wasteful and have not been satisfactory for practical production purposes. 1

This invention provides a method for the production of uniformly accurate, longitudinally slit tubes with continuously bevelled ends from initially flat stock material,

in a practical and efficient manner.

It is essential that the bevelled or other ends-formed on such tubes be continuous up to the very edges of the slits. The method of this invention enables continuous production of-pins of uniform accuracy, continuously bevelled along their ends and to thevery edges of their slits.

The accompanying drawings illustrate practical embodiments of the invention; it will be apparent to those skilled in the art that pursuant to the teachings of the present disclosure, many additions and modifications may be made within the spirit and scope of the invention. All of such modifications which utilize the principlesof the invention as set forthherein and come Withinthe terms of the appended claims shall be deemed to be within thewpurview and scope of this invention.

in the drawings:

Fig. 1 is a schematic view of the step of preforming the blankto an intermediate stage, pursuant to this invention, I t

Fig. 2 is a vertical sectional, partly perspective of the blank, taken on line 2 2of Fig. 1 V i Fig. 3 is a view of the blank pre-formed at line 3-3 of Fig. 1,

Fig. 4 is a vertical sectional view taken on line 4-4 of Fig. 5,

Fig. 5 is an elevational view taken on line 5-5 of Fig. 4,

Fig. 6 is a perspective View of the punch and anvil members shown in Figs. 4 and 5,

Fig. 7 is an enlarged fragmentary plan view of connected tubes preformedand grooved pursuant to the invention,

Fig. 8 is a vertical sectional view, taken on line 8-8 of Fig. 7,

Fig. 9 is a schematic view illustrating a rolling mechanism which may be used to complete the pins from the preformed state indicated in Figs. 7 and 8, to the final form indicated in Figs. 11 and 12.

Fig. 10 is a schematic view of the final step of separation of connected tubes.

Fig. 11 is a fragmentary plan view of a pin completed pursuant to this invention, and

Fig. 12 is an end elevational view thereof, taken on line 12-12 of Fig. 11.

The method of this invention is designed for fabrication of pins such as shown in Figs. 11 and 12 from flat blanks of material as indicated at 10 in Figs. 1 and 2. These blanks of material may be, for example, of continuous strip form, as shown in Fig. 1, fed from a suitable roll or other source of supply.

Pursuant to the invention, the flat blank of material is preformed from the original flat form thereof shown in Fig. 2 to the form shown in Fig. 3 by forming the longitudinal edges 11, 12 of said blank into arcuate marginal portions to impart a generally C-shaped transverse crosssection, by passing the blank 10 between dies or rolls, such as, for example, the rolls 15, 16 in Fig. 1.

The blank 10 is then passed beneath a punch 20 or other impressing member. The punch 26 is provided with an upstanding edge 21 which is transversely of U-shaped outline and which is provided with a chamfered face 23 (see Fig. 4), whereby, when said punch is brought down onto the preformed blank of Fig. 3 passed therebeneath with the marginal edges 13, 14 directed away from the punch, a transversely continuous chamfered groove 17 (Fig. 8) will be impressed continuously onto the top and marginal edges of the blank and to the very extremities of the marginal edges 13', 14', see Fig. 8. The parts are so proportioned that the contour of the punch conforms to that of the preformed (Fig. 3) blank so that the impressed chamfer groove 17 will be continuous along the blank at precisely that point thereon which is intended to be the chamfered end in the completed pin (Fig. 11). In the operation of impressing the chamfer groove 17 onto the preformed pin, punch 24 is caused to move partly through the blank; the groove 17 will correspondingly extend only partly therethrough (Fig. 8). Thus, the blank is provided at one and the same point with a chamfer groove 17 and (thereby) with a portion of reduced thickness.

The step above described, wherein the punch impresses the blank with the transversely continuous chamfer groove 17, will be repeated as the blank moves beneath punch 24 (as in direction 28 of Fig. 4) at those points along the blank which have been predetermined to divide it into pins of the desired length. As shown in Fig. 4, the step of impressing the chamfer groove 17 into the preformed blank may be performed at a station in the machine or apparatus at which an anvil 38 is disposed beneath punch section 24 and in registry therewith. The anvil has an upstanding face 31 of complementary outline to that of the cavity 22 of the punch but of predetermined lesser dimensions, so that the preformed blank ill of Fig. 3 will be smoothly supported upon the upstanding face 31 of the anvil 30. In practice, the blank 10 may be a long, continuous strip, fed from reels or in suitable lengths or sections through the rolls 15', in or other mechanism for providing the fiat blank 18 with the arcuate marginal edges 13, 14. The blank so preformed is then passed under the punch to impress the same, at each cycle of descent of the punch, with the chamfer groove 17 and reduced portion 18. The blank is then passed through suitable mechanism, as, for example, forming rolls 26, 27, 28, 29 of Fig. 9, which will form the blank, intermediate its arcuate marginal edges 13, 14 into the desired final circular or other form and to dispose said edges in close parallel spaced relation as shown in Fig. 12. As shown in Fig. 10 in the final step, the blank is advanced to a position at which a pressure or stress-exerting member 32 will engage the blank to fracture it at the point 18 thereof which marks the 'the axis and break cleanly at said'point.

end of the chamfer groove17 and the location of reduced portion -18. In Fig. there is shown'an impact member 32 which descends'onto the tube at or adjacent to the weakened point 18' causing the tube to flex along The specific arrangement shown in Fig. 10 or other suitable means to attain this-end maybe used for that final step. If desired, the pin may be ,passedthrough a suitable apertured member 33 which will stabilize the same in the step of fracturing it at its weakened points 18'. Member 32 may be on the order of a hammer or striker moving downwardly ontothe blank as the latter moves through the machine, or the blank'may be otherwise subjected to stress and strain at the weakened points 18 thereof by use of other tools or means adapted to that end.

It has been found, in practice, that, pursuant to the method above described, tubes may be manufactured with uniform accuracy. The tubes break at the points '18 cleanly and without roughened edges.

Pursuant to the present invention spring pins of uniform cross-section, as indicated at 35 in Fig. 12 and with slits or openings'36 and bevelled ends continuous to the very edges of said slits may be made. This type of pin is particularly desirable where it is necessary for the pin to fiex to absorb stresses, and permits it to be slightly contracted for insertion and to expand to exert continual tension against the walls of the opening uniformly throughout the length of the pin. The pin may be heat-treated so that it may be used over and over again due to its inclination to resume its original diameter, indicated in Fig. 12.

The above described bevelled face 23 of the punch 20 may be duplicated as at 23', said "chamfered faces 23, 23' being of such predetermined angle as may be desired for the chamfered groove 17, thus providing the punch with an edge '21'of V cross section. In some instances, as, for example, where it is desired that the opposite ends of the pins shall not be correspondingly bevelled-for example, where it is desired that one end of the pin shall have a chamfer groove of greater angle than the other, this objective may be attained by correspondingly varying the angles of the chamfer faces 23, 23 of the punch 20, which provide the chamfer grooves 17, 17' (Fig. 7). The punch may be formed of .sections 24, 25 secured together or used independently depending on the particular application at hand. By timing the speed of movement or feeding of the blank through the apparatus relative to the cycles of descent of the punch, the length of the finished pins 27 may be predetermined.

The arcuate marginal edges 13, 14 may be preformed on the blank at that step of the method which is illustrated in Fig. 3 to constitute arcs or slit ends of the final form 35 (Fig. 12) into which the tube isto be made or to constitute an intermediate between theflat original cross section form of the blank shown in Fig. 2 and the final cross section of the pin indicated in Fig. .12, the final completion of the desired cross section being attained in the step of rolling or otherwise completing cross sectionally the form of the pin as by use of the Fig. '9 "or other forming apparatus.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

l. The method of forming a fiat non-bevelled metal blank having spaced parallelmargins into a longitudinal slit pin with a continuously bevelled end, which comprises first forming the longitudinal margins of said flat blank into arcs directed in the plane of the blank having a tZ-shaped transverse cross-section, then moving a punch member having an upstanding edge of the V shaped cross-section, transversely of U-shaped outline generally corresponding to .the so preformed blank in cross-section onto the blank and partly thereinto, to thus impress the said blank with a continuous transverse V recess from edge to edge, while the blank has said C-shaped transverse cross-section, subsequently forming the blank to a final generally tubular form, wherein the recess follows the contour of the blank as a continuous recess from edge to edge thereof, and breaking said blank medially of said V to define a smooth bevel continuous from edge to edge thereof.

2. The method of forming a flat non-bevelled metal blank having spaced parallel margins into a longitudinal slit pin with a continuously bevelled end, which comprises first forming the longitudinal margins of said fiat blank into arcs directed in the plane of the blank having a C-shaped transverse cross-section, thereafter disposing said blank above an anvil and then moving a punch member having an upstanding edge of the V-shaped cross-section, transversely of U-shaped outline generally corresponding to the so preformed blank in cross-section'onto the blankand partly thereinto, to thus impress the said blank with a continuous transverse V recess from edge to edge, while the blank has said O-shaped transverse cross-section, said 'anvil having a face of C-shaped outline corresponding to that of the upstanding edge of the punch, supporting the blank while the punch is impressing the recess thereon, subsequently forming the blank to a final generally tubular form, wherein the recess follows the contour of the blank as a continuous recess from edge to edge thereof, and breaking said blank medially of said V to define a smooth bevel continuous from edge to edge thereof.

References Cited in thefile of this patent UNITED STATES PATENTS 653,902 Bray July 17, 1900 1,366,063 Culhane Jan. 18, 1921 1,756,403 Thomson Apr. 29, 1930 1,924,230 Davis Aug. 29, 1933 1,931,162 Kranz Oct. 17, 1933 2,222,842 Humphrey Nov. 26, 1940 2,248,172 Pruckner July 8, 1941 2,582,063 Zitzewitz Jan. 8, '1952 2,630,174 Poteet Mar. 3, 1953

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