US2689389A - Socket for wire strands and the like - Google Patents

Description

C. C. SUNDERLAND S AND THE LIKE 2 Sheets-Sheet l I \HI/// r mat IN V EN TOR.

CHARLES C. SUNDERLAND ATTORNEY p 21, 1954 c. c. SUNDERLAND socxm FOR WIRE STRANDS AND THE LIKE 2 Sheets-Sheet 2 Filed April 26, 1952 k OI INVEN TOR.

CHARLES C SUNDER'LAND BY ATTORNEY Patented Sept. 21, 1954 UNITED STATES PATENT OFFICE .Charles C. Sunderland, Seaside Park, N. J., as-

slgnor, by mesne assignments, to John A. Roeblings Sons Corporation, Trenton, N. J., a corporation of New Jersey Application April 26, 1952, Serial No. 284,670

. 3 Claims.

The present invention relates to apparatus and amethod for securing the ends ofwire strands, wiresropes, wire cables, or similar wire materials... .More particularly, the invention relates toga. socket for securing the ends of highstrength wire materials of the type mentioned and to a method of applying such a socket.

-In socketing strand and the like, it is customary to separate the ends of the wires of the strandand to embed themin a body of filling material, such as zinc or tin. A basket surrounds the strand and is adapted to receive, engage, and grip the body of filling material, and thereby grip and hold the strand. The front or strand end of-the body of filling material may be given a taperedconical shape, and the interior of the basket may be correspondingly conically tapered, so as to give a gripping action when the strand is placed undertension. That is, both the cone offilling-material and the basket are tapered to smaller cross-section toward the strand end, and when the strand isplaced under: tension, the cone of filling material is drawn farther down into the tapered basket, resulting in compression of the fillingmaterial, and consequent gripping V of the strand.

One difficulty withsuch arrangements heretofore results from the fact that the filling materials begin to flow if the pressure towhichthey are subjected exceeds a certain amount. For example, zinc, which is often used for the filling material, begins to flow-if the pressure exceeds the front portion of which is conically tapered and the rear portion of which is cylindrical. Within the cavity of the basket and gripped by its walls is a shaped body of filling material having the separated ends of the wires of the strand embedded therein. The body of filling material has two conical surfaces, a front one :and a rear one. The front one converges toward the front, that is, toward the main length of strand, and engages the similarly conically shaped front portion of the wall of the cavity. The rear one converges toward the rear. Cooperating with and forming a portion of the front conical surface of the filling material" is a tapered steel bushing surrounding the strand and having a conical outer surface fitting snugly with .a wedging action against the front, conically tapered portion of the wall of the cavity. A tapered sleeve is forcibly wedged between the rear conical surface of the filling material and the cylindrical rear portion of the wall of the cavity of the basket.

- In applying the socket, the cone of filling mate- 40,000 pounds per "square inch. It has consequently been necessary heretofore to design the shapeand size of the sockets so thatthe pressure on thezincfwouldnot exceed 40,000 pounds per square men when the strand was placed under a tension equal to its ultimate strength. Such designs have resulted in sockets larger than are desirable. In some applications, for example, inprestressed concrete, :it is often necessary to group a number of strands together, and the best designs heretofore haveproduced sockets of such large outside diameter as to make it impossible to obtain the required close spacing of strands in a concrete beam.

One object of the present invention is to providea socketing method and apparatus which, by operating upon a novel principle, makes possible the design and production of a socket of reduced outside diameter, while gripping the wire with sufficient intensity to develop the ultimate strength of the strand, or like material.

In one embodiment of the present invention, there is provided a basket having a cavity therein,

rial is drawn into the basket, and tension is applied to the strand, thus tending to compress the filling material. While this tension is on the strand, the tapered sleeve is forced into the rear end of the basket with its leading edge wedging between the filling material and the basket. This pressure of the tapered sleeve against the filling material further increases the pressure exerted throughout the filling material, thereby increasing its gripping action on the strand embedded therein. In onepreferred embodiment, in applying the socket, the pressure in the filling material is thus increased, by the combination of tension on the strand andthe force applied to the tapered sleeve, to an extent great enough to provide a gripping action suflicient to develop the ultimate strength of the strand. The tapered sleeve, in addition to serving the purpose of increasing the pressure on the filling material also serves as a seal at the rear end of the basket. The inner wall of the sleeve, at its smallest diameter, fits closely enough to the wires inthe filling material to prevent escape of the filling material, even though the pressure may be great enough on the filling material to cause it to tend to flow, if it were not confined within the cavity. The bushing at the front end confines the filling material at this point. In some embodiments the pressure is, in fact, greater than that at which the filling material flows. v i

. .-Because themethod and apparatus of the present invention operate upon the novel principle of compressing the filling material within an enclosed confine, and because of the consequent possibility of obtaining pressures of a magnitude heretofore impossible, much greater gripping action is obtained, and one result is the important advantage of being able to reduce the diameter of the socket and still develop the ultimate strength of the strand. The reduction of diameter of the socket is an especially important advantage where close spacing of strands is needed, as, for example, in, prestressed concrete.

Another advantage, also flowing from the novel principle of compressing the fillingmaterial within definite confines, is that a variety of materials" may be used for the filling material. In addition to zinc, lower-compressive-strength materials, such as lead and antimony, may be used, because the gripping action is purely mechanical. The fact that such materials are compressed be yond the pressure at which they fiow does not impede the satisfactory operation of the apparatus.

The above mentioned, as well as other obiects, together with many advantages obtainable the practice or the present invention will be readily comprehended by persons skilled in the art by reference to the following detailed description taken in connection with the anneked drawings, which respectively describe and il-lustrate preferred embodiments of the invention, and wherein Fig. 1 is an assembly view, longitudinal section, showing the socket ap nedto the strand, including the double-cone of filling material within the basket. v I w 1 Fig. 2 is a longitudinal f'sectional view of the tapered sleeve, which is shown in its ultimate position in Fig. 1

Fig. 3is an end elevational View of the tapered sleeve of Fig. 2, v

Fig.4 anenlarg'eddetai l view in longitudinal section showing the shape of the forward, lower edge of the taperedsleeve ofFig. 2.

Figs. 5 and 6 are side elevational and end elevational views, respectively, of the tapered bushing which terminates the forward end of the cone-of filling material, 'as shown in Fig. -'l.

Fig. 7 is a longitudinal sectional view of the basket alone.

"Fig. 8 is an end elevational View of the basket I Figs. 19 "and 9 are longitudinal sectional and end elevational views respectively of the nut shownin operative position in Fig. 1.

Reference is made to Figures '1fand'7. There is shown a main, outer sleeve or basket having an internal cavity IQ of circular cross section. Throughout the greater portion of 'its length, in its left hand or forward portion, the cavity 13 is conical in shape, tapering to smaller diameter toward the forward end. In a smaller portion of its length, toward the "rear of the basket, the cavity 'l-3 is of cylindrical cross section. The basket H is open at its right-hand or rear end. There is an opening "l5 through the front wall of tl'ie bask t I I*, leading to the Cavity l3.

Internal threads are provided toward the extreine rlght hafld end (if the cavity 13 in the basket H. External threads are provided at the right-hand end of basket, extending a greater distance along it than do'the internal threads.

In applying the socket described herein to strand or the -1ike,the basket TH is first slipped overthe'end'ofthe strand, bypassingthestrand,

designated by the reference numeral I! in Fig. 1, through the opening l5 at the front of the basket. The strand is pushed through the basket so that its end projects out the right-hand end far enough so that a shaped, double-tapered body or button of filling material, for example, zinc, may be formed on the strand, in a manner to be described.

' After the strand 1'! is pushed through the basket, a steel tapered bushing [9, shown in Figs. '5 and 6-, is passed over the strand, with the smaller end of the bushing being toward the main lengthef strand. The outside wall of the bush- 'ing is tapered so as to be of conical shape, and

adapted to fit shdfgly against the tapered, conic'al interior wall of the cavity l3, when ultimate- Iy in place.

The wires of the strand I! are then separated so that they flare throughout a major portion of their lengths, and then converge toward their extreme ends, shown in 1. The separated length of strand, with the bushing 19 in its desired ultimate position on the strand, are then placed in a mold, not shown, and a shaped body or button 2| of filling material, for example, zinc, is "cast.

The shape of the zinc button is shown in Fig. 1:. Starting "at the left hand or front end, it will be seen that the steel bushing 19 is cast as apart of the zinc button, so as to form the front end of it. The bushing fits very closely over the strand, and the zinc fill-s any small spaces be"- tween the wires of the strand and the inner wall of the bushing I9. The zinc button is formed to have a conical tapered shape on its forward end throughout the major portion of its length, so as to fit the tapered walls of the basket 4 1-.

In casting the zinc button, the rnold has means, such as a ring, adapted to hold the flared wires away from the walls of the mold, so asto provide a suitable layer of nine on the outside of the wires. In the absence of this arrangement, there would be a tendency for the wires to touch the walls of the mold, andas a result, the wires would have some bare region, uncoated with zinc, at the points where they touch the walls of the mold. The ring of the mold which holds the wires inwardly produces a groove 23 in the zinc button. --As may be seen in Fig. '1, the walls of this 'groove taper so as to converge toward the bottom of the groove. It will -be understood that the wires of the strand do not fl-areputwardly beyond the diameter of the bottom of the groove 23. To'either side of the groove 23, the-zinc button 21 has a-flat region, as shown in 1. To the left of this flat region the button-converges conically toward the main length of the strand. To the right '-of this fiat region the button converges conically toward the end cf the strand. Hence the button, =or shaped body of filling ma;- terial, *has a portion tapering toward the front, and a shorter portion tapering toward the rear.

After the button 2 1 'is formed it is moved down into the basket *I I gasshown in-Fig. 1. The strand 4*! is then placed under tension, for example, a tension equal to about two-thirds-of the ultimate strength 'of the strand. A tapered sleeve 25, shown in Figs. 3 and '4, is then forced into the back erid "of the basket, by jacking means, not shown. The final relative positions "of the basket n, the b'iitt'cin 24, and the tapered sleeve -25 are shows-merally in the shape of a wedge pointing toward theleft or forward end of the basket.

The tension on the strand II, in drawing the tapered button 2| into the tapered cavity [3, causes compression in the button. Additional compression is caused by forcing the tapered sleeve 25 inwardly so that its tapered portion engages the tapered portion of the right hand end of the button. t i As may be seen in Fig. 1, the inner tapered surface of the tapered sleeve 25 engages the rear conical tapered surface of the button. When the tapered sleeve 25 is driven in, the compression produced within the zinc button cause the wires of the strand to .be gripped by the zinc with suflicient intensity to develop the ultimate strength of the strand.

In this manner very high pressure is exerted on the zinc filling material, and in some embodiments the. pressure is suificiently great to exceed the pressure at which the filling material begins to flow. It is possible in this manner to produce pressures as high as, for example, 100,000 pounds per square inch, provided the basket and other components are strong enough. The various components of the socket must be designed to resist the existing pressure which is developed in the filling material, and must confine the filling material and prevent it from escaping from the cavity l3. Escape of the filling material at the front or left hand end of the main sleeve II is prevented by the bushing [9. The outer wall of this bushing fits snugly against the wall of the cavity I3, and, having a tapered fit with this cavity, the greater the pressure of the button, the tighter the fit between the bushing I9 and the wall of the cavity I3. Because of the close fit of the bushing over the strand, even under the existing pressure within the button, zinc may not escape the cavity I3 between the bushing and the strand.

The tapered sleeve 25 has a cylindrical longitudinal opening toward its rear end. This opening tends to prevent the wires from being pushed by the sleeve when it is forced into the basket. At the right-hand end of the button, the wires are jammed closely together, and the inner surface of the tapered sleeve 25 fits sufficiently closely around these wires that an effective seal is provided against escape of zinc through the opening in the right-hand end of the tapered sleeve 25.

In the illustrative embodiment it may be seen that the right-hand end of the button, after the socketing operation has been completed, extends to approximately the right hand extremity of the tapered portion of the wedge 25.

As the tapered sleeve 25 is driven in, the pressure produced in the zinc tends to cause this sleeve to expand somewhat, particularly near its left-hand or leading edge. This edge is designed so that, even when the sleeve expands, the edge will not tend to dig into the wall of the basket.

.of the rear cone of the button and of the tapered sleeve 25 should be flat enough to produce such a good bond that the sleeve will remain in position under all working conditions. A suitable angle of taper of the inner surface of the sleeve 25 with respect to its outer surface, in a practical em bodiment, is 5 43' (tan.=0.l). I

As may be seen in Fig. 1, not only does the outer surface of the filling material have two conical portions, one converging toward the front and one toward the rear, but the wires of the strand also have this over-all shape. That is,.firstcthey diverge from the main length of the strand,.and then they converge at theirends. i

In the manner described, the button 2i is com-.- pressed to the full compression which would exist at the breaking strength of the strand, and this is done at the time the socketing arrangement is attached. One advantage of this arrangement is that, when the strand and its socket is in actual use, there will be no further forward movement of the button as the working load is applied.

Usually the socket is applied to the strand at the factory. After the socket is applied, as described above, the tension in thestrand may be released. In using the strand bearing its socket, perhaps at a later time and place, a threaded member such as a jack rod, not shown, is screwed into the internal threads at the right-hand end of the basket II, and tension is applied to the strand through the jack rod and the basket. When the tension has been adjusted in this manner to the proper value, the nut 35, which is carried on the external threads at the right-hand end of the basket H, is positioned at the right point so that its left-hand or forward surface engages a suitable member adjacent the socket, and in this manner the nut 35 holds the socket in the desired position.

To illustrate the high values of filling material pressure which may be employed, and the usefulness of designs in which the pressure exceeds that at which the filling material begins to flow, it will be stated that, in one embodiment, when the socket is applied, in order to develop substantially the ultimate strength of-=the strand, the pressure on the zinc filling material is about 85,000 pounds per square inch. 'When the strand and socket are first installed, the pressure may be about 70% of the original 85,000-poundfig ure, or 60,000 poundsper square inch. After the strand and socket have been in use for long enough for conditions to stabilize, the pressure maybe about 50% of the 85,000-p0und figure, or more than 40,000 pounds per square inch, and hence more than the pressure at which zincbegins to flow. It will be understood that in various applications of the present invention the pressures employed will be different. i

Since the pressure may satisfactorily exceed the value at which the filling materialbegins to flow, the design is not limited to high compressive-strength filling materials. Lower-compressive-strength filling materials, such as lead, antimony and others maybe used, since the gripping of the wire is purely mechanical. This gripping action is of much higher intensity than has been possible insockets heretofore. I

With the method and apparatus of the pres-- ent invention, the size of the socket, and particularly its diameter, may be significantly reduced as compared with prior arrangements, .and still obtain the ultimate strength of the strand. As an illustration, for 11% inch diameter strand,

. a socket heretofore havingan outside diameter creases '7 socket having an outside diameter of about 4 Although in the preferred embodiment the shape of the tapered surfaces of the various tapered members conical, it will be understood that other converging or tapered shapes may be employed.

While the present invention, in its broadest sense, is not to any particular dimensions, suitable dimensions for one practical embodiment of a socket applicable to 1%; inch bridge strand are shown below. The letters in the table below correspond to reference letters on the drawings.

Angular dimensions Linear dimensions :1 1% e 11%;; inches ;f is inches g 3 inches 11 1.397 innhes Jc 2:878 inches on 4 inches n 2.2% inches :q 3%,} inches 1' 2.4284 inches 3 2 am inches t 1.889 inches While a suitable form of apparatus and method to be used in accordance with the invention have been described in some detail, and certain modifications have been suggested, it will be understood that numerous changes may be made without departing from the general principles and scope of the invention.

I claim:

1. .A connection for securing wire strand, wire mm, wire cable, or similar wire material, coma basket, said basket comprising a main sleeve having a longitudinal cavity extending therethrough and a wire material receiving opening at its front end connecting with said cavity, the wall of said cavity having a conical iront portion diverging toward the rear and terminating in a cylindrical rear portion, a shaped body of low-:compressiveastrength filling material formed on said wire material having a front conical portion converging toward the front and fitting snugly against said front conical portion of the wall of said cavity and a rear conical portion converging toward the rear in the region of said cylindrical portion of said cavity, a bushins surrounding said wire material and forming an integral partof said body at the :front thereof, said bushing fitting snugly against said conical front wall of :said cavity and sealing the .iront end of :said :cavity 'against escape of said filling inateri-al, and a tapered sleeve having an inner tapered wall engaging and pressed against 'said rear conical portion of said shaped body and an outer cylindrical wall engaging and pressed against said cylindrical rear portion of said wall of said cavity, said tapered sleeve being i orcibly wedged between the rear portion of said shaped body and said basket and being :shaped to pre vent :said filling material from escaping from the rear :end of said cavity or from expanding a rearward direction even under pressures at which it may :flow, said shaped body of low-compressire-strength filling material filling interstices of said cavity from the rear surface of said bushin to the rcarmost point where said filling material engages said tapered sleeve, and being incapable of moving farther forward within said main sleeve.

2. A connection for securing wire strand, wire rope, wire cable, or similar wire material comprising a basket having an internal cavity the wall of which tapers to decreasing cross section toward the front end of said cavity, said basket having an opening in its front wall leading into said cavity, said wire material extending through said openings into said cavity and terminating in a tapered body comprising low-compressivestrength filling material and the portions of said wire material embedded in said filling material, said tapered body being shaped to have a front tapered portion fitting the front portion of said cavity and a rear tapered portion decreasing cross section toward the rear, said front tapered portion being longer than said rear tapered portion, said basket having an opening at its rear end leading into said cavity, a tapered sleeve extending into said rear opening and litting snugly against the walls thereof, said tapered sleeve being wedged against the rear tapered portion .of said tapered body with sufiicient force to cause said filling material to be under such great pressure within said cavity that :said socket and said filling material grip said wire material sufficiently strongly to develop substantially the ultimate strength of said wire material, and means including a tapered bushing surrounding said wire material at said front end of said cavity and including said tapered sleeve at the rear end of said cavity adapted to prevent said filling material from escaping from said cavity, despite the pressure to which it is subjected, even under conditi'onsof flow, said tapered bushing being integral with said body.

3. In a connection for securing wire strand, wire rope, wire cable, or similar wire material, in combination, a shaped body of low-compressive strength filling material formed .on the end of said wire mate-rial, said body having a front portion tapering to smaller cross section toward the front, terminating in a tapered bushing, and a rear portion tapering to smaller cross section toward the rear and terminating at the end of said wire material, and sweating means enclosing sail-d body and confining :said filling material so as to prevent it from escaping from said socketing means even at pressures at which it flows, said soc'ketlng means including a hollow basket the inner wall of which said front tapered portion of said body of filling material and said tape-red bushing, and a wedging member having a tapered sleeve portion 's'l-idably forced into the rear end of said basket and wedged between the inner wall of said basket and said rear tapered portion of said body of low'cornpressivestrength filling material so as to "compress said filling material, said filling material substantially completely filling the space within said basket from said bushing to the rear of said body of filling material, except for the space occupied by said wedging member, said wire material within said basket being prevented by said filling material and said socketing means from moving -farther forward respect to said.

2,689,389 1 9 References Cited in the file of this patent UNITED STATES PATENTS Number Number Name Date 3,839

677,036 Laurent June 25, 1901 r 4056 728,689 Am Ende May 19, 1903 121702 2,041,385 Van Laanen May 19, 1936 2,292,711 OConnor Aug. 11, 1942 1 i) FOREIGN PATENTS Country 9 Date Great Britain Sept. 24, 1879 Germany Feb. 20, 1879 Great Britain June 9, 1896

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