Title:
Cotter pin spreader
United States Patent 2431664


Abstract:
My invention relates to cotter pins, with. special reference to .cotter pin assemblies constructed for self-spreading action, and is directed specifically, to. improvements in the spreader member employed in such assemblies. In a cotter pin of the present type the assembly comprises a- cotter...



Inventors:
Strid, Sven J.
Application Number:
US63688745A
Publication Date:
11/25/1947
Filing Date:
12/22/1945
Assignee:
T & S CORP
Primary Class:
Other Classes:
254/104
International Classes:
F16B21/12; F16B21/14
View Patent Images:
US Patent References:
2386887Supporting clip1945-10-16
2166614Cotter pin1939-07-18
1925804Method of making channeled bag frames1933-09-05



Foreign References:
GB125547A1919-04-24
Description:

My invention relates to cotter pins, with. special reference to .cotter pin assemblies constructed for self-spreading action, and is directed specifically, to. improvements in the spreader member employed in such assemblies.

In a cotter pin of the present type the assembly comprises a- cotter pin member or cotter pin proper, having the usual two arms in combination with a spreader member extending between the two arms. During shipment and handling of the assembly prior to use, the cotter pin member and the wedge member are in retracted positions relative to each other. When the cotter pin is ultimately driven into place -for service as a retaining means, the spreader member is immobilized at. a certain point, so that the-subsequent relative longitudinal movement of the cotter pin member causes the arms of the cotter pin member to be wedged apart at their inner ends by the spreader member.

The general construction of such a spreader member in a cotter pin assembly as taught by the prior art is to be found in the Taylor Patent No. 1,768,721, and the- Strid Patents Nos. 2,153,440, 2,166,614, 2,373,983, and 2,400,960. Such a spreader member is fabricated by steps including cutting a blank of suitable configuration out of sheet metal and bending the blank to form two side flanges .of tapering configuration to serve as wedge means in the spreading of the cotter pin.

In all of these prior disclosures the configuration of the. blank relative to the lines along which the metal is bent to form the flanges is such as to oppose the bending action unduly, and is such as to result in. distortion and weakening of the material adjacent the inner ends of the flanges.

In consequence the blank-is so difficult to form that the forming cost is relatively high. Often the metal yields to the forming forces unevenly so that one side flange is higher than the other. 4 Close inspection is required and not all of the rejected pieces can be salvaged by further processing.

The object.. of the present invention is to improve: the construction and the method of con- I struction of such a spreader member by eliminating, undue.; resistance- to the bending of the spreader flanges and by avoiding weakening of the. materialby strain and distortion. In general, this object is. attained by changing the initial configuration of the spreader blank to a configuration permitting both ends of the bend lines for the side flanges to extend to the edges of the blank. When the bend lines. are. thus arranged to extend from edge to edge of: the blank the metal may be bent. 5. in: a clean-cut: manner in a single forming operation without adversely affecting, the metal of the blank adjacent to the inner ends of the bend lines. The new procedure in construction saves 6 labor, lightens the burden of inspection, and greatly reduces the number of rejections. I have discovered that- a certain pinching action in the older practice was the cause of the uneven forming of the side flanges, and I now avoid such pinching action.

The above and other objects and advantages of my invention will be apparent in the following detailed description taken with the accompanying drawings.

In the drawings, which are to be regarded as merely illustrative; Fig. 1 is a side elevation of a typical cotter pin assembly including my improved spreader member; Fig. 2 is a fragmentary plan view on an enlarged scale of a spreader blank according to one practice of my invention; Fig. 3 is a fragmentary plan view of the spreader fabricated from the blank of Fig. 2; Fig. 4 is a fragmentary side elevation of the finished spreader; Fig. 5 is a transverse section taken as indicated by the line 5-5 of Fig. 4; Figs. 6, 7 and 8 are views corresponding to Figs. 2, 3 and 4, but showing the preferred practice of my invention; Fig. 9 is a fragmentary plan view similar to Fig. 7, exemplifying a third practice of my invention; and Figs. 10, 11 and 12 are views corresponding to Figs. 6, 7 and 8, indicating how such a spreader member has been fabricated heretofore.

In the cotter pin assembly shown in Fig, 1, the cotter pin member, generally designated 20, is n formed from a. single piece of suitable half round stock, and comprises the usual two arms 21 interconnected by a. loop 22, the arms being sprung together. Inserted between the: arms 21 is a spreader member 23 having two side flanges 25 . at one end of the usual tapered configuration to serve as wedge means for spreading the arms 21.

At the inner end of the spreader member 23 is a pair of laterally: extending wings 26 to serve two:purposes. One of the purposes is to provide 0 an enlargement to- limit, the movement of the spreader member, into-a bore when the cotter pin assembly is being installed, thereby to hold the spreader member stationary during the final movement of the cotter pin member into the bore.

5 Thus the relative movement between the spreaIde member and the cotter pin member is provided as required for the spreading action. The second purpose of the two wings 26 is to limit lateral movement of the spreader member relative to the cotter pin member prior to installation of the device, and for this purpose the two wings are sufficiently bent to engage the opposite sides of the cotter pin member 20.

The particular spreader member 23 shown in Fig. 1 is also provided with small tabs or flanges 27 on its opposite side that fit snugly against the cotter pin member 20 to prevent lateral movement between the spreader member and the cotter pin member at a second point. Other expedients may be employed to serve the purpose of the tabs 27, as shown in the Strid Patents Nos. 2,166,614 and 2,400,960. None of these expedients conflict with the improvement disclosed herein.

The present invention is primarily concerned with the construction of the side flanges 25 that provide the wedging action for spreading the cotter pin member 20. In all five of the prior disclosures mentioned above the leading end of the spreader member, including the wedging side flanges 25, is formed in the manner indicated by Figs. 10, 11 and 12.

Fig. 10 shows a flat sheet metal blank having a body portion 28 with parallel side edges 30 and having an enlargement 31 at one end with diverging side edges 32. It is to be noted that the inner ends of the diverging side edges 32 meet the parallel side edges 30.

Since the width of the body portion 28 of the usual blank is approximately the diameter of the cotter pin assembly, and therefore close to the diameter of the bore into which the cotter pin is to be installed, it is obvious that the overall width of the finished spreader member across the two wedging side flanges must be appreciably less than the width of the body portion 28. Otherwise the upstanding side flanges would not lie entirely within the circle defined by the bore and would prevent the leading end of the spreader member from entering the bore. It is apparent, then, that to form the finished spreader member from the blank shown in Fig. 10 it is necessary not only to bend the metal of the blank 900 to form the two wedging side flanges, but also to pinch the metal.

The necessity for pinching action is apparent from the position of the dotted lines 29 in Fig. 10, representing the lines on which the metal is bent to form the side flanges. Note that these lines terminate at their inner ends inward from the side edges of the blank.

Fig. 11 indicates how the metal is pinched to form the two wedging side flanges 33, the pinching action being concentrated in the regions designated 34 adjacent the inner ends of the side flanges. In practice the wedging side flanges 33 of Fig. 11 are best formed in two steps, and often additional hand work is required to permit the finished pieces to pass inspection. Even with two forming steps the metal is distorted or mutilated at the regions 34 to such a degree that the metal across the spreader member between the two regions 34 tends to be weakened either by crystallization or by the formation of small fissures.

It is to be borne in mind that the wedging action for spreading the ends of the cotter pin member involves high longitudinal stress in tension at this particular part of the spreader member.

In one practice of the present invention illustrated by Figs. 2 to 4, I employ a sheet metal blank, generally designated 35, having the usual body portion 28 and end enlargement 31, the body portion having parallel side edges 30 and the enlargement having the usual diverging side edges 32. The blank 35 differs from the blank shown in Fig. 10 in having marginal notches or recesses 36 at the inner ends of the diverging side edges 32. Thus the diverging side edges 32 terminate in the recesses 36 instead of joining the parallel side edges 30.

The recesses 36 are deep enough to meet, or at least come very close to, the longitudinal lines along which the metal is to be bent to form the two wedging side flanges of the finished spreader member. These bend lines are indicated by the dotted lines 37 in Fig. 2. In other words, it is desirable that both ends of these lines of bend extend to the edges of the blank, and the recesses 36 are provided to bring the side edges inward to the bend lines.

Fig. 3 shows the wedging side flanges 38 that are formed by bending the sheet metal upward along the dotted lines 37. It is clearly apparent that while the bending of the flanges 38 reduces the width of the wedging member at its leading end to less than the width of the body portion 28, nevertheless no pinching action is involved in the reduction in width. The metal is bent upward along the lines 37 in a clean-cut manner and without causing any strain on the metal between the two marginal recesses 36.

While the particular blank configurations shown in Fig. 2 is practical, it does result in the formation of a distinct and somewhat abrupt shoulder 40 at the inner end of each side flange 38, as may be seen in Fig. 4. It is desirable, therefore, to bevel the leading end of the corresponding arm 21 of the cotter pin 20 to ride easily over the shoulder 40.

The preferred practice of my invention illustrated by Figs. 6, 7 and 8 has the advantage of eliminating the shoulder 40, as will now be explained. The blank, generally designated 41 in Fig. 6, has a body portion 42 with parallel side edges 43, and has an end enlargement 45 with diverging side edges 46. Here again the blank configuration includes marginal recesses 47 at the inner ends of the diverging side edges 46. In this instance, however, the recesses 47 are formed in part simply by extending the diverging side edges 46 well inside the longitudinal zone defined by the parallel side edges 43. Bending the blank 41 as indicated by the two longitudinal dotted lines 48 results in the formation of the two wedging side flanges 50 of Figs. 7 and 8. Fig. 8 clearly brings out the fact that the described method of fabrication results in smoothly functioning wedging surfaces, free of any abrupt shoulder.

Fig. 9 illustrates a third practice of my invention wherein, strictly speaking, no recesses are employed. In this instance I make the body portion 51 of the spreader relatively narrow to accomplish the same purpose as recesses, viz: to permit the previously described bend lines to extend at their opposite ends to the edge of the sheet metal material. As is apparent in Fig. 9, the side edges 52 are spaced apart not more than the distance between the side flanges 53. In this specific instance the parallel side edges 52 are substantially equal to the spacing between the side flanges 53 so that the lines along which the blank is bent to form the side edges are substantially continuations of the parallel side edges 52.

The crux of the matter is that the side edges of the body portion of the blank extend inwardly, 2,431,664 5 at least inside the planes of the outer faces of vided wit the side flanges and preferably at least to the substanti planes defined by the inner faces of the side two side flanges. This relationship may be achieved either configura by cutting marginal recesses in a blank having 5 cotter pir a body portion of conventional width, or may be flanges e) achieved by simply narrowing the width of the another e' body portion. 5. A sp It will be apparent to those skilled in the art of the cl that various changes and substitutions departing 10 erally thi from the described constructions and procedures material may be made within the scope of my appended jections b claims, strip to f I claim as my invention: one end tl 1. A spreader member for use in a cotter pin 15 as wedge of the character described, comprising a sheet having ms metal strip provided with laterally extending the inner projections bent substantially at right angles to spectively said strip to form two side flanges at one end said flang thereof of tapering configuration to serve as wedge 20 6. A sp] means for the cotter pin, said strip having mar- of the chE ginal recesses in its side edges at the inner ends plastically of said flanges. laterally e 2. A spreader member for use in a cotter pin at a right of the character described, comprising a sheet 25 adjacent metal strip provided with laterally extending pro- tion to se: jections bent substantially at right angles to said said strip strip to form two side flanges at one end thereof edge adja of tapering configuration to serve as wedge means extending for the cotter pin, said strip having marginal re- 30 flange. cesses in its side edges at the inner ends of said flanges, said recesses extending inward at least to the planes of the inner surfaces of said flanges.

3. A spreader member for use in a cotter pin The foll' of the character described, comprising a sheet 35 file of thi metal strip forming a flat longitudinal body provided with laterally extending projections bent substantially at right angles to said strip to form Number two side flanges at one end thereof of tapering 1,925,804 configuration to serve as wedge means for the 40 2,166,614 cotter pin, the side edges of said body at the inner 2,386,887 ends of said flanges lying inside the planes of the outer faces of the flanges.

4. A spreader member for use in a cotter pin Number of the character described, comprising a sheet 45 125,547 metal strip forming a flat longitudinal body proh laterally extending projections bent ally at right angles to said strip to form flanges at one end thereof of tapering tion to serve as wedge means for the i, the inner faces of each of said side rtending from one edge of said strip to dge of the strip.

reader member for use in a cotter pin laracter described comprising, a gen.n flat strip of plastically deformable provided with laterally extending proent substantially at right angles to said orm at least two side flanges adjacent lereof of tapering configuration to serve means for the cotter pin, said strip trginal recesses in its side edges adjacent ends of said flanges and extending reinward to substantially the bases of es.

reader member for use in a cotter pin aracter described comprising, a strip of deformable material provided with xtending projections bent substantially angle to said strip to form a side flange one end thereof of tapering configurarve as wedge means for the cotter pin, having a marginal recess in its side cent the inner end of said flange and inward to substantially the base of said SVEN J. STRID.

REFERENCES CITED owing references are of record in the s patent: JNITED STATES PATENTS Name Date Hiering --------_ _ Sept. 5, 1933 Strid --------__ _ July 18, 1939 Eckel ---------- Oct. 16, 1945 FOREIGN PATENTS Country Date Great Britain ---- Apr. 24, 1919