US 3181341 A
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Description (OCR text may contain errors)
y 4, 1965 J. A. THORNTON ETAL 3,181,341
DIES FOR COMPRESSION TOOLS Filed Oct. 4. 1961 2 Sheets-Sheet 1 rtZyM May 4, 1965 Filed Oct. 4, 1961 FIG.5
J. A. THORNTON ETAL 3,181,341
DIES FOR COMPRESSION TOOLS 2 Sheets-Sheet 2 FIG 4 lira E0475,
United States Patent M 3,181,341 F913 (XENERESSEGN TOULS .lohn A. Thornton, fit. Louis, and (Carl G. Zemeis, tilayton, Mo, assignors to Jana-es R. Kearney Eorporation, St. Louis, Mo, a corporation of Delaware Filed Get. 4 1961 .Ser. No. 142,918 g t Claims. (Qt. 72-ditl) This invention relates to compression tools used to squeeze compression fittings onto electric line conductors and wires. To simplify the following disclosure, the description will be limited to one example of compression fitting which is a cylindrical ductile metal sleeve dimensioned to slidably receive the ends of either stranded or solid conductors inserted from its opposite ends for a substantial distance. When such a fitting is subsequently compressed circumterentially at a plurality of spaced locations along the length of the fitting by a tool applied to the exterior of the fitting, the sleeve grips the exterior of each line conducor inserted therein thereby forming a mechanical and electrical splice.
The tool used for compressing the sleeve, especially on the smaller sizes of fittings, is one with pivoted jaws that operate in a scissor-like fashion. These jaws are operated by long handles of wood or other insulating materials. Usually the actuating connection between the handles and the pivoted jaws resemble that of a bolt cutter. Such an actuating mechanism gives the necessary high mechanical advantage to produce huge forces between the jaws by manually operating the handles. Each jaw carries a generally semi-circular half die piece about one-half inch wide, and, when the die pieces are brought together on the fitting by the scissoring action of the jaws, the portion of the fitting within the dies is compressed by the huge force of the jaws thereby forming an indentation around the fitting. This indentation is interrupted at diametrically opposite points by protruding metal fins coincidental with the locations where the die pieces meet on diametrically opposite sides of the fitting. One of the objections to this form of tool is that when a plurality of indentations are made along a sleeve, there is a noticeable axial curvature imparted to the sleeve along itsaxis. This effect becomes more pronounced the longer the sleeve. It has also been discovered that straightening the sleeve subsequent to compression to correct or eliminate the curvature has a tendency to loosen the grip of the sleeve on the line con ductor sometimes along one side so that moisture can enter and corrosion impair the efficiency of the joint electrically. It has also been discovered that by reversing the position of the handles of the tool from one side to the other side of the sleeve alternately for each application of the tool, it is possible to eliminate the axial distortion produced to a large degree. This, however, cannot be done in every application because the lineman cannot apply the tool in this manner from his position on the pole.
It is one of the objects of this invention to provide a set of die pieces for compression tools. used on compression fittings which will eliminate axial distortion of the fitting when the tool is applied to compress the fitting at spaced locations therealong.
It is still another object of this invention to provide a st of die pieces for a jaw type compression tool which will equalize the axial extrusion of the metal of the compression fitting circumferentially of the fitting to eliminate residual axial distortion.
Further objects and advantages of this invention will appear from the following description which is in such full, clear and exact terms as will enable any one skilled in the art to make and use the invention when taken with the accompanying drawin s forming a part thereof and in which:
i'hlhlfi ll Fatented May 4, 19fi5 FIG. 1 is a schematic illustration of a compression tool of the pivoted jaw type with die pieces constructed according to this invention;
FIG. 2 represents a line conductor splice formed by a compression tool shown in PEG. 1
FIG. 3 is a schematic illustration of die action in this pivoted jaw type of tool with the dies which are of shape similar to that of the compression fitting;
FIG. 4 is a schematic illustration of die action in a pivoted jaw type of tool with dies which are of shape asimilar to that of the compression fitting;
FIG. 5 is a schematic illustration of dies, such as shown in FIG. 4-, modified slightly to produce a polygonal indentation.
Turning now to FIG. 1, therein is illustrated a typical form of jaw type compression tool. In this tool, handles l and 2 are pivoted together at the pin 3 and are provided with the stops 4 and 5 to limit movement of the handles toward one another. Handle 1 carries a pin 7 upon which is pivoted the end of the jaw 8. Likewise, handle 2 carries a pin 9 upon which the inner end of the jaw 19 is pivoted. law 8 is hinged on the pin it to a link 12. law it is hinged by pin 13 on the opposite end of the link 12. The active face M of jaw 8 and the similar face 16 on jaw 10 are provided with aligned sockets 18 and 2.0 for receiving a pair of die pieces. A similar pair of sockets 22 and 24 may also be provided for smaller die pieces.
The handles 1 and 2 are shown separated opening the jaws i5 and it During operation of the handle toward one another to close the jaws 8 and iii, the pivot point 3 moves upwardly toward the jaws thereby producing a toggle-like action to clamp the jaws together. The maximum force exerted, of course, will occur as the pivot point 3 approaches the line of centers of the pivot points 7 and because of its toggle action, and the structure is usually arranged so that this occurs just as the stops t and 5 close. The toggle action of the handles 1 and 2 produces a huge force tending to clamp the jaws together on the opposite side of their hinge points. Thus when suitable dies are inserted in the sockets 18 and 2A? or 22 and 24, this huge force is available to cause the dies to cornpress and actually extrude the metal of a connector sleeve or fitting. It will be understood that a die piece, for example, is. fitted into each of the sockets 18, 2d, 22 and 24, if desired, with the smaller die pieces in the sockets 22 and 24 at the tip of the jaws where the force available is less. Two die pieces 226 and 228 are schematically illustrated in FIG. 1.
In FIG. 3 the full lines indicate the symmetrical type of die in a position when fully closed. The dotted lines indicate the position of the same dies after they have been closed to the point where they contact the outside of the fitting to be compressed, which is indicated therein as 3%. The dies 26 and 28 are symmetrical dies in the sense that each has a semi-circulator cavity formed by the surface 31 in die piece 26 and 32 in die piece 28. These same surfaces are indicated as 31' and 32" in the open position of the dies. When the dies are fully closed, it
will be noted that the surfaces 34 and 35 are slightly spaced so as to permit extrusion of the metal between them. Similarly the surfaces 36 and 37 diametrically opposite the surfaces 34 and 35 are similarly slightly spaced for the same purpose. In this view, it will be noted that the circular surfaces 31' and 32 contact the outer periphery of the sleeve 31 at a plurality of points which have been indicated as 41), 41, 42 and 43. Parallel lines interconnect the points id and 43 and 41 and 4.2, and this forms a good illustration of the difference in the amount of metal in the sleeve 30 which projects between the surfaces 36, 37 and 34, 35. Approximately this amount of metal of the sleeve 39 will be extruded between the adjacent surfaces with more metal being extruded outwardly between the surfaces 36 and 37 than inwardly between the surfaces 34 and 35. The difference in the amount of metal extruded in each instance has been sectioned and indicated separately as A and B. In the closed position of the dies, this same amount of metal appears as A and B, and these portions of metal A and B form projecting fins protruding outwardly from the circumferential indentation formed by the die surfaces 31 and 32. This will serve to illustrate the fact that more extrusion has taken place on the outside of the sleeve nearest to the nose of the tool. It has been discovered that extrusion is not confined in a circumferential direc tion on the sleeve exclusively. What has not been realized is that some longitudinal extrusion of this metal occurs, and, since there is a difference in the degree of extrusion produced in the sleeve outwardly of the jaws, i.e., toward the nose, compared with that inwardly of the jaws, i.e., toward the hinge, this then is the reason there will exist a tendency for axial distortion of the sleeve 33. Preferably, this elfect is due primarily to the fact that, while the dies are symmetrical, the movement of the jaws is not rectilinear.
One embodiment of the instant invention, shown in FIG. 4, overcomes this difiiculty in a very effective manner. This view is similar to FIG. 3 in that the closed position of the dies 126 and 128 is illustrated in full lines. The open position of the dies, where they have first made contact with the outer surface of the sleeve 130, is shown in dotted lines. The same reference characters are used in FIG. 4 as in FIG. 3 with 1% added. The inner active or working surfaces of each die are illustrated as 131 and 132 in the closed position. In the open position, the same surfaces are indicated as 131 and 132. In the latter position, the dies are closed far enough to make the first contact with the sleeve 130. It will be noted by a comparison that the points 141 and 142 corresponding with points 41 and 42 in FIG. 3 have not changed relative location. However, there is a distinct difference between the location of the points 146, 143 and the corresponding points 40 and 43 of FIG. 3. The contour of the surfaces 131 and 132 is asimilar to a circle, and (considered at the time the die faces make their initial four-point contact with the exterior circular surface of sleeve 30 or 13G) this change in the inner contour of die faces 31 and 32 has brought the axis of the circular surface of sleeve 130 closer to points 140 and 143 than the axis of the circular surface of sleeve 30 is to points 40 and 4 3, thus making room in the inward (i.e., toward the pivot axis) half of the die cavity for the amount of metal which might otherwise be extruded between the surfaces 136 and 137. As the dies close, the metal in the sleeve 130 is therefore displaced inwardly of the jaws before any of the metal is extruded outwardly into the fin 2a. Similarly, the metal is extruded into a fin into the space 2!) between the surfaces 134 and 135. With this die arrangement, approximately the same amount of extruded metal will form 2a as at 2b, and approximately the same axial extrusion will take place at both places so that there is no axial distortion of the sleeve 36*. What has happened is that the amount of metal in the fin 2a is approximately the same as the amount of metal in the fin 2b, and, since the space between the surfaces 136, 137 and the space between surfaces 134, 135 is approximately equal in the closed position of the dies, there will take place a longitudinal balanced extrusion at the parting sides of the dies. This being the case, the axial distortion in the fitting or the sleeve connector is avoided. A plurality of tool applications along the fitting leaves the fitting axially undistorted regardless of the position in which the dies are placed upon the fitting. The fitting does not take a form of a bend when the dies are used, but remains axially undistorted after a plurality of applications along the fitting as shown in FIG. 2. Subsequent straightening of the fitting is completely unnecessary, since the shape of the 4. cavities within the die can be contoured so as to avoid the consequences of non-rectilinear movement of the compression tool.
One of the features of these dies is that the active surfaces 131 and 132 are contoured to cause the metal to flow inwardly rather than outwardly due to the difference in slope of the curve outwardly of points 141 and 142 from that adjacent 149 and 143 which wedges the fitting bodily inwardly of the dies instead of outwardly thereof. Thus, the working faces of the dies are smoothly curved in FIG. 4 in a direction inwardly to cause the metal to flow in this direction. It is also possible, however, to incorporate the same features whether the working surfaces are smooth or polygonal, and FIG. 5, hereinafter described, illustrates one Way in which this may be accomplished.
In FIG. 5, the same portions of the die pieces and the die pieces themselves, which correspond with those shown in FIG. 4 and also in FIG. 3, are indicated by the same reference characters with 2-80 added. In this view, the working surfaces of the die pieces are illustrated as 231 and 232, respectively, in their closed position. In their open position where contact is first made with the exterior of the fitting, these same surfaces are indicated as 231 and 232. The surfaces 231' and 232' make initial contact with the fitting 230 at the points 246, 243 and the points 241, 242. As in the previous modification, the working faces of the die pieces, indicated as 231 and 232, are shaped so as to cause the metal of the fitting 230 to flow inwardly of the die instead of outwardly. As the dies close to the positions 231 and 232, the metal of the fitting is extruded into the portion 31) so that the amount of metal in the fin 3a is approximately equal to the amount of metal in the fin 31). Where the fins have equal amounts of metal, or substantially so, the amount of longitudinal extrusion lengthwise of the sleeve 239 on either side will be balanced, thereby minimizing axial distortion of the fitting 230. FIGS. 4 and 5, therefore, iilustrate two forms of the invention, and the position of the die pieces, when opened and closed, represent their approximate relative positions when installed within the sockets provided in the jaws 8 and 10 of the tool. The operation of the die pieces is substantially identical, and this description will be limited to the action of the die pieces 226 and 228 when installed within the sockets provided in the jaws 8 and 19 of the tool. To use the die pieces shown, it is first necessary to install the die piece 226 of one size in the socket 18 of the jaw 8, and the die piece 228 in the socket 26 of the jaw 10. The two die pieces will be matched to accommodate a single size of fitting. The die pieces may have suitable catches or locking means to hold them securely within the sockets of the jaws 8 and 16, respectively. Only die pieces of the proper indicated size can be used on a fitting of certain exterior dimension. With the fitting placed upon the ends of the line conductor and the tool ready for use with the die pieces installed, the lineman then opens the jaws of the tools by spreading the handles 1 and 2, places the die pieces in the jaws over the sleeve or fitting and moves the handles 1 and 2 toward one another thereby closing the jaws. The first contact made between the fitting and the jaws is indicated in both FIGS. 4 and 5 by the position of the active surfaces of the die pieces 131', 132, 231 and 232. Further movement of the handles 1 and 2 toward one another produces the extrusion of the metal of the fitting in a direction inwardly of the jaws. This is caused by the contour of the active faces of the die pieces adjacent points Mil-142 and 241-242, which produce a fiow of metal inwardly of the jaws of the tool by a wedging action due to their relative slope with respect to the slope of opposing faces 14644-3 and 240-243. The lineman thcn continues the squeezing action by moving the handles 1 and 2 until stops 4 and 5 come together. During the final movement of the jaws in compression on the fitting, the fins 3a and 3b are formed by the fact that the surplus metal is squeezed outwardly between the surfaces 236 and 237 and 234 and 235. The handles 1 and 2 are then parted and the jaws removed from the fitting. As will be seen from FIG. 2, this series of operations is repeated along the length of the fitting 230 with each operation leaving a circumferential indentation in the surface of the fitting. When the operation is complete, the line conductor is firmly secured in place within the fitting, but it remains axially undistorted throughout its length. Whereas with the symmetrical dies, the fitting has taken on a definite axial bend, the use of the dies which are asimilar to the fitting (e.g., acircular when, as in these embodiments, the uncompressed fitting is circular) has not effected any axial distortion whatsoever. No subsequent straightening of the fitting is required, and, consequently, the grip of the fitting around the line conductor is uniform circumferentially of the line conductor.
Changes in and modifications of the construction described may be made without departing from the spirit of our invention or sacrificing its advantages.
Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:
1. A compression tool for securing a tubular compression fitting on a line conductor or wire comprising a pair of pivoted jaws, manually operated means for moving said jaws together and for multiplying the manual force applied to move said jaws, a pair of die pieces mounted one in each of said jaws, cooperating mating faces on said die pieces for engagement with opposite sides of said compression fitting and dimensioned to form a circumferential indentation in said tubular fitting when said jaws are brought together, said die pieces having active faces forming opposite cavities which are symmetrical with respect to a plane equally spaced from said faces and extending between said jaws inwardly toward the pivoted ends of said jaws, said jaws when mated forming a single die cavity which is asimilar in shape with respect to the original cross-sectional shape of said fitting, in that opposite relatively convergent faces inwardly of said jaws within said cavity have portions of less slope with respect to said plane than the slope of adjacent surfaces on the original cross sectional shape of said fitting and the slope of corresponding die portions on opposite relatively convergent faces outwardly of said jaws to provide for initial flow of the extruded metal of said fitting inwardly toward the pivoted ends of said jaws as said jaws close, and then a substantially equal fiow of metal inwardly and outwardly of said jaws as said die pieces fill, and opposite cavities between said die pieces into which the metal can flow from within said die pieces in like amounts to equalize the strain lengthwise of said fitting and minimize distortion of said fitting in this direction.
2. The combination as defined in claim 1 in which the active faces of said die pieces are smoothly curved between said cavities.
3. The combination as defined in claim 1 in which said active faces of said die pieces have a plurality of straight sides.
4. A compression tool for securing a tubular compression fitting on a line conductor or wire comprising, a pair of jaws pivoted for relative movement, manually operated means for moving said jaws together and for multiplying the manual force applied to move said jaws, a pair of die pieces mounted one in each of said jaws, cooperating mating faces on said die pieces for engagement with opposite sides of said compression fitting and dimensioned to form a circumferential indentation in said tubular fitting when said jaws are brought together, said die pieces having active faces forming opposite cavities which are symmetrical with respect to each other but asymmetrical within themselves in that the active faces of the respective cavity halves nearer the jaw pivot converge together more pointedly in the direction toward said pivot than the active faces of the halves thereof remote from said pivot converge together in the direction away from said axis.
References Cited by the Examiner UNITED STATES PATENTS 1,761,521 6/30 Eastman. 2,086,400 7/37 Benizer. 2,254,416 9/41 Burns. 2,814,222 11/57 Sanders. 2,869,407 1/59 Swanson. 3,084,575 4/63 Klein.
WILLIAM FELDMAN, Primary Examiner.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,181,341 May 4, 1965 John A. Thornton et a1.
It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
Column 3, lines 19 and 20, for "Preferably" read Probably column 4, line 71, after "faces" insert at Signed and sealed this 8th day of February 1966.
ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner of Patents