US2111505A - Method for making a forged clamp - Google Patents

Description

March 15, 1938. c. s. CARD 2,111,505

METHOD FOR MAKING A FORGED CLAMP Filed April 20, 1936 2 Sheets-Sheet 1 I-MIFLE S F FD, INVENTOR.

, ATTORNEY.

March 15, 1938. c. s. CARD METHOD FOR MAKING A FORGED CLAMP Filed April 20, 1936 2 Sheets-Sheet 2 CHAEL ES R R0, INVENTOR.

ATTORNEY.

Patented Mar. 15, 1938 Y i I METHOD FOR MAKING A FORGED CLAMP Charles S. Card, Cortland, N. Y., assignor to The Brewer-Titchener Corporation, Cortland, N. Y., a corporation of New York Application April 20,

4 Claims.

This invention broadly relates to the art of so called strain clamps whose metal body is adapted to be forged in one piece and more particularly pertains to a dead end clamp for the holding of a looped transmission conductor or other cable when subjected to high mechanical tension and 'in which the cable grip is distributed over a considerable portion of a spirally grooved seat with the slack cable end anchored in place by keeper means.

. In the present instance, a planiform, cross-sectionally V shaped groove of the incomplete annular type is resorted to in which such arcuate groove contour is preferably given a gradually decreased radius of curvature toward the slack cable end to provide for snubbing action. One such groove end may be equipped with a tangentially disposed hanger arm adapted to cooperate with a suitable insulator or the like clamp supporting member. The respective extremities of my arcuate groove are subtended by an integral bridge piece having keeper means mounted thereon.

The primary object of my improvements is to devise a simple method by which a clamp of the indicated character can be effectively forged up in successive die forming operations by first drawing a flanged cup-shaped body planchet which after centrally piercing its crown region, permits of reshaping suchpierced edge of the planchet to complete an arcuate groove at the minimum of labor and other production costs.

Embodied herein are also other processing features contrived to promote the end in View and all of which aspects will hereinafter be more explicitly set forth. Reference is had to the accompanying two sheets of drawings which are illustrative of certain preferred embodiments and in which drawings:

Fig. 1 shows a plan view of my forged clamp assembly when looking axially toward a side flange of my arcuate groove, and Fig. 2 represents an end view thereof.

Figs. 3 and 4 are respectively taken along the sections 33 and 44 of Fig. 1, while Fig. 5 detalls the finished groove formation as taken along line 55.

Fig. 6 illustrates in plan, an initial deep drawn blanking operation herein resorted to prior to inturning one of the side flanges of my arcuate clamp groove.

Figs. 7 and 8 are respectively taken along the sections 1-! and 8-8 of Fig. 6 to define my cup shaped planchet as formed prior to shearing out its crown wall. Y

Referring first in detail to my clamp as an article of manufacture of the annular kind, depicted in Figs. 1 to 5, this may comprise an arcuate 1936, Serial No. 75,292

H and I2. The respective marginal edges of these lips are faced outwardly and extend in substantial parallelism along the major portionof the groove length. The rounded base of each groove preferably lies in a common plane without being given any pronounced helical formation. The respective extremities of one such groove flange namely i I, may be spanned by a relatively fiat, integral bridge piece I3.

The cable It is intended to wedgingly rest in and be grippingly engaged between the groove flanges to efiect the desired snubbing action. To this end, the groove bottom or seat is preferably given an oval-like contour such that the taut cable may be wrapped tangentiafly on its larger groove radius RI and with the slackened cable end brought radially inward to conform with the smaller radius R2. Said bridge piece may be provided with a lug or boss l5 that is apertured in a direction parallel to the axis of my arcuate snubbing groove. Complementary pairs of axially offset guide knobs such as IE or the like ridges may be located to straddle -the slack cable end for centeringpurposes. A depressed region may extend crosswise between each such pair of knobs to provide for an undulated seat contour adapted to correspondingly indent the clamped cable end.

A T shaped keeper bolt has a threaded shank ll entered through said lug aperture and this serves to draw the clamped cable toward the bridge piece. The transversely disposed cross bar or keeper head IB may be inclined with respect to the shank axis as in Fig. 4 and each oppositely disposed bar projection may be undercut to provide for the interchangeable dished recesses l9 and respectively having differently sized cable receiving radii. By turning-said T-head around the shank, the slack end of either a relatively large or small conductor can=thereby be tightly gripped and anchored to my clamp body.

Tangentially projecting from one of the groove side walls in a counterwise direction to the pull of the tensioned cable, is a hanger arm 2lof which the extremity is preferably but not necessarily, given a bifurcated formation 22 adapted to receive a conventional coupling pin 23. The described clamp may be initially supported in place and have the cable I4 drawn around its comparatively short groove, whereupon the keeper is applied to secure the tensioned cable. In order to keep the tensioned cable pull in alignment with that of the hanger arm, I preferably warp one groove end as at illA.

Having described the structural features of my clamp design, the improved mode for forging the same may be traced by reference to Figs. 6 to 8. The billet is preferably forged to provide for a deep drawn or cup shaped body planchet such as 25 provided with a divergent hanger arm 28. In the swaging of same, its matrix or drafted die blocks may be parted along the line 26, it being understood that the resulting flash therealong is to be neatly trimmed.

One side flange component of my clamp groove is initiated during the forming of said planchet, as shown. The tangentially disposed forked hanger arm is simultaneously swaged up with said flange component and the bridge piece 29 provided with imprinted guide knobs or ridges such as 30A, 303, etc., together with a cooperating keeper boss 21. A feature of my forging process resides in the shaping up of a potential complementary groove side flange such as [2 of Fig. 2. In order to initially draw and gather the stock required therefor, I introduce the intermediary step of forging a cross-sectionally s'ocketed or cup shaped planchet 25 havirg a flared mouth or radially extended rim 3| together with a laterally reenforced flash portion that constitutes a transverse crown wall 32 of the kind represented in Fig. 7. The medial region of such artificial crown wall is preferably kept relatively thick to prevent metal rupture'during the required deep drawing operation, whereupon the thinner marginal region of said crown wall is pierced to leave a trimmed edge on the planchet along a shear line such as 33, which edge is thereupon crimped radially outward into its dotted position 34 of Fig. '7 by the use of suitable forming tools. When thus shaped up, this completes my arcuate clamp groove 35, whose structural aspects correspond to. the previously described similar element iii.

Subsequent to being forged as in Fig. 6, the arm fork 28 may be skewed about its longitudinal axis to lie in the quadrature Fig, 1 position. For this purpose, it is preferred to reheat a localized shank region of the arm 2| and while hot, subject said region to an axial twist without warping or otherwise deforming the remainder of the completed forging. Such twisting operation may be performed before or after piercing the crown wall 32.

When such cable groove is given a finite contour length and the respective ends are subtended by a unitary bridge piece, then the contiguous warped skirt portion 36 of my cup shaped planchet may be kept thinner than the remainder of the skirt wall. Said thinner skirt portion may thereupon be sheared out along the circuitous path indicated in dotted outline at 40 (see Fig.7) to provide for an unobstructed groove gap adjacent to the finished bridge piece 29. This same underlying method may also be applied to the making of an endless groove, except that in such instance, the entire perimetric skirt length of my cup shaped planchet is similarly crimped.

It will be observed that by virtue of my improvements, it becomes possible to forge as contrasted to casting, a one piece strain or dead end clamp that is free from hidden material flaws. This requirement is particularly appropriate in connection with the installation of high tension conductor clamps because of the obvious danger that may be associated with an inadvertent dropping of a sustained transmission line. My clamp also possesses a high degree of strength for a given weight and is in all respects admirably suited for the purpose intended. In addition, the forging method herein disclosed materially facilitates the economical manufacture of arcuate clamp grooves on a rapid productive basis.

Other advantages will be apparent to those skilled in this art, it being understood that various changes in the structural clamp details or the mode of shaping the side flange thereof may be resorted to in carrying out the present teachings, either with or without an integral hanger arm, all without departing from the spirit and scope of my invention heretofore described and more particularly pointed out in the appended claims.

I claim:

1. The method of swaging a billet into a one piece body having a cross-sectionally V-like groove including complementary side flanges each provided with an. arcuate marginal edge, and. which method consists in initially forging and thereby drawing a cup shaped planchet to include arim region that is spread radially outward to form one of said side flanges having a protuberance gathered thereon and the bottom of which cup shape is spanned by a crown wall, piercing said wall, and then by a crimping step reshaping the pierced wall edge of the planchet to extend outwardly into substantial parallelism with the free marginal edge of said one side flange and thereby complete the aforesaid groove formation.

2. The method of swaging a billet intoan annular clamp body having an arcuate groove of finite length including complementary side flanges of which the respective ends of one such flange are united by a bridge piece, and which method consists in initially forging and thereby drawing a cup shaped planchet including an endless skirt wall that is spanned by a crown wall and the free rim region of which skirt wall is spread radially outward to form the aforesaid one flange having an integral bridge piece extending between the terminals of said one flange, a bridge piece thereacross and the skirt piercing said crown wall and severing a portion of the skirt contiguous to the bridge piece, and then by' a crimping step reshaping. the pierced wall edge of the planchet to extend radially outward into substantial parallelism with the free marginal edge of said one side flange to complete said groove formation.

3. The method of swaging abillet into an annular clamp body having a cross-sectionally V-like groove including complementary side flanges, and which method consists in forging and thereby drawing a socketed planchet provided with a cup shaped cavity whose bottom is initially closed by a crown wall and the rim region of which cavity is spread radially to form one of the aforesaid flanges together with an integral hanger armextending tangentially therefrom, piercing the crown wall of said socket, and then by a crimping step reshaping the pierced wall edge ofv the planchet to extend radially outward into substantial parallelism with the free marginal edge of said one side flange to complete said groove formation.

4. The method of swaging a billet into a one piece body shaped to initiate a cross-sectionally v-like groove including complementary side flanges, and which method consists in hot forging and thereby drawing a socketed planchet having acavity whose bottom wall is initially closed and the rim region of which cavity is spread radially to form one of the aforesaid flanges together with integral arm means extending tangentially therefrom, and then reheating a localized medial region 01' said arm and axially twisting the free endregion thereof.

CHARLES S. CARD.

CERTIFICATE OF CORRECTION. 3 Patent No, 2,111,505.. March 15, 19

CHARLES s, CARD.

It is hereby certified that error appears in the printed specifioation of the above numbered patent requiring correction as follows: Page 2, second column, lines 56 and 57, strike out the words "a bridge piece thereacross and the skirt'f; and that the said Letters" Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5d day of May, A. D. 1958..

7 Henry Van Arsdale, Acting Commissioner of Patents.

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