Wire Come-Along

The present invention relates to wire gripping devices and, more particularly, to wire come-alongs for stranded cable.

Wire grips, per se, have been used for a number of years to lay structural cables or electrically conducting wires. The prior art wire grips generally conform to one or another of the following types. Bolt-on grip: a two-piece grip is bolted onto a cable to provide an attachment point for a pulling force. Such a grip may cause damage to the cable by improper torquing of the bolts; it may present a hazard through cable slippage because of damaged or dirty bolt threads; and, it is generally not useable with soft cable, such as aluminum cable. Moreover, the attachment and the attachment process are generally time consuming. Wedge grip: a pair of wedges are mounted within a frame and bear directly upon opposed side surfaces of the cable; the cable contacting surfaces of the wedges may include abrasions or teeth to aid in preventing cable slippage. The contacting surface area between the cable and the wedges is generally relatively small and produces high stress concentrations which may result in damage to the cable. The opposed wedges are physically incapable of circumscribingly distributing the applied forces about the cable, which distribution tends to induce deformation of the cable. For cables of soft material, such as aluminum, physical damage generally always results which reduces the cable strength and where such cable is used to conduct electricity, creates impedance discontinuities and attendant power losses. Wire end grips: these grips are specifically configured to grip the end of the cable and are incapable of being attached at any other point along a cable.

The following United States patents are representative of one or another of the above types of wire grips: U.S. Pat. Nos. 482,975, 1,029,345, 1,504,087, 1,854,140, 2,386,908, 3,343,808, 3,776,586, 3,852,850 and 3,868,748.

It is a primary object of the present invention to provide a wire come-along for applying tension to a stranded cable without flattening or damaging the strands of the cable.

Another object of the present invention is to provide a wire come-along for stranded aluminum cable.

Yet another object of the present invention is to provide a wire come-along which exerts an equal circumferentially distributed pressure about a substantial length of a cable.

Still another object of the present invention is to provide a wire come-along attachable to any one of a plurality of different sized wires by substituting differently sized inserts within the wire come-along.

A further object of the present invention is to provide a quickly and easily attachable and detachable wire come-along.

A still further object of the present invention is to provide a relatively lightweight wire come-along useable in conjunction with any sized cable.

These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.

The present invention may be described with greater specificity and clarity with reference to the following figures, in which:

FIG. 1 is a perspective view of the wire come-along mounted upon a stranded cable.

FIG. 2 is a cross-sectional view of the wire come-along taken along lines 2--2, as shown in FIG. 1.

FIG. 3 is a partial cross-sectional view of the wire come-along taken along lines 3--3, as shown in FIG. 2.

FIG. 4 illustrates the top view of a further embodiment of the wire come-along.

FIG. 5 is a cross-sectional view taken along lines 5--5, as shown in FIG. 4 .

The salient features of the wire come-along are generally illustrated in FIG. 1 and details thereof are depicted in FIGS. 2 and 3. Frame 1 is formed by a plurality of bridges, such as bridges 2, 3, and 4, mounted upon a U-shaped rod member 5. The bridges may be isosceles triangular shaped in plan form and include a depression 10 extending inwardly from the base of the triangle. Each of the bridges includes a pair of opposed slots 19 and 20 extending laterally away from depression 10. These slots house and support roller bearing surfaces 21 and 22. Apertures 11 and 12 are disposed in proximity to opposed corners of the bridges, which apertures are configured to receive respective arms 13 and 14 of rod member 5. The bridges are mounted upon arms 13 and 14 and welded thereto in general alignment with one another but spaced apart from one another, as illustrated. The central section 15, including apex 16, of rod member 5, is bent with respect to the axis of arms 13 and 14 such that apex 16 is offset with respect to the longitudinal axis defined by aligned depressions 10.

A split hinged sleeve 25 includes two half sleeve sections 26 and 27 which are pivotally attached to one another by hinges 28 and 29. A plurality of pairs of opposed wedges 30 and 31, 32 and 33, 34 and 35, are attached to sleeve sections 26 and 27, respectively. Two piece annular flanges 36 and 37, 38 and 39, 40 and 41, are also attached to sleeve sections 26 and 27 adjacent respective ones of the pairs of wedges. These flanges serve as additional structurally supporting elements for the attached wedge and serve the secondary purpose of uniformly transmitting to the attached sleeve section the forces exerted upon the pertaining wedge. It may be noted that the ends of these flanges in proximity to the hinge line of split sleeve 25 are configured to accommodate pivotal movement of the split sleeve sections.

The locations of wedges 30, 31, 32, 33, 34 and 35, with respect to split sleeve 25 correspond to the positions of roller bearing surfaces 21, 22, 23, 24, 17 and 18. By inspection, it may be appreciated that as frame 1 is repositioned with respect to split sleeve 25 by applying a pulling force upon the frame at apex 16, the roller bearing surfaces are urged toward the butt end of the wedges. The force exerted upon the wedges and transmitted to split sleeves 26 and 27 will force the sleeves toward one another and exert a compressive force upon a wire or cable 7 lodged therein. A continuingly applied pulling force at apex 16 will cause cable 7 to be placed in tension commensurate with the force applied.

Whenever cable 7 to be pulled is of a diameter substantially less than the internal diameter of split sleeve 25, an insert, such as insert 45 may be employed. Insert 45 is formed by a pair of split sleeves 46, 47 which have an external radius approximately corresponding to the internal diameter of split sleeve 25 and an internal radius approximately corresponding to the diameter of the cable 7. Annular flanges 48 and 49 extend from one end of the split sleeves and bear against flanges 36 and 37 of split sleeve 25. Thus, an axial force exerted upon frame 1 is transmitted through split sleeve 25 and acts upon flanges 48 and 49 to draw cable 7 lodged within insert 45 in the direction of the applied force. Attachment screws 50 and 51 maintain the split sleeves of insert 45 attached to the respective one of split sleeves 26 and 27.

Referring particularly to FIGS. 2 and 3, roller bearing surfaces 23 and 24, are mounted within slots 19 and 20 by means of shafts 55 and 56 extending transversely to the slots and embedded within bridge 3. Collars or spacers 57, 58, 59 and 60 may be employed to position the roller bearing surfaces within their respective slots.

As inferred above, split sleeves 46 and 47 of insert 45 are lodged within the respective one of split sleeves 26 and 27 and maintained in place by attachment screws 51 and 52. These attachment screws permit rapid and facile removal or substitution of insert 45 and thereby permit a single wire come-along, as described above, to be used with many differently sized cables 7.

In operation, split sleeve 25 is pivotally opened up to receive and close upon a cable to be pulled or placed in tension. An insert may or may not be employed, depending upon the diameter of the cable. Frame 1 is placed into engagement with split sleeve 25 such that the plurality of pairs of roller bearing surfaces thereof engage respective pairs of the wedges extending laterally from the split sleeve. Upon exertion of a pulling force upon apex 16 at central section 15, the roller bearing surfaces will be urged to ride upon their respective wedges toward the butt end of the wedges. The increasing lateral dimension of the wedges, in combination with the fixed position of the roller bearing surfaces, will force split sleeve sections 26 and 27 to pivot toward one another about the hinge line and exert a clamping force upon cable 7. By constructing the split hinged sleeves of relatively robust high strength material and through employment of the segmented annular flanges, the forces exerted on the wedges by the roller bearing surfaces will be essentially uniformly distributed throughout the split sleeve 25 and present a uniform clamping force upon a large surface area of the cable. The large uniformly distributed clamping force tends to preclude stress concentrations upon the cable and minimizes the potential for deformity and damage to the cable.

After the cable has been pulled or placed in tension and anchored in place, frame 1 is readily disengaged from split sleeve 25 by tapping it in the direction of the pointed end of the wedges. The resulting relative longitudinal movement between frame 1 and split sleeve 25 permits the two to be readily disengaged. Thereafter, the split sleeve sections are pivoted about their hinge line to release the cable.

As particularly illustrated in FIG. 2, the width of slots 19 and 20 are sufficient to accommodate intrusion of wedges 32 and 33. The width of depression 10 in proximity to slots 19 and 20 is sufficient to receive split sleeve 25 and to allow for some lateral movement of the split sleeve; however, as wedges 32 and 33 are axially repositioned in response to relative movement between frame 1 and split sleeve 25, the wedges will begin to intrude within the adjacently located slots. Such intrusion will interfere with relative vertical movement between the split sleeve and the frame. Hence, frame 1 cannot "fall off" or otherwise become disengaged from the split sleeve except and until the frame and the split sleeve have been longitudinally positioned with respect to one another such that the wedges are of insufficient depth to intrude into their respective slots. Thereby, inadvertent disengagement between frame 1 and sleeve 25 is effectively inhibited.

An expiermental model of the above described wire come-along measured thirty-two inches in length, nine inches in width, and weighed approximately sixty pounds. It was pull tested to sixty thousand pounds, at which point, the one and three quarter inch clamped cable being pulled snapped. No damage or deformation to the wire come-along was noted; moreover, no damage to the pulled cable due to the clamping force was noted.

Where extremely high tensional forces may have to be applied to a cable, the roller bearing surfaces and supporting shafts described above may fail. The embodiment illustrated in FIGS. 4 and 5 incorporates substituted elements for the roller bearing surfaces to accommodate extremely high loads.

For the sake of brevity, only those elements illustrated in FIGS. 4 and 5 which differ from the corresponding elements illustrated in FIGS. 1, 2 and 3 will be described. Rod member 5 is replaced with rod member 5a having a rectangular cross-section and of substantially greater mass. It is mounted within and welded to slots disposed within bridges 2, 3, and 4. The roller bearing surfaces have been replaced by wedges 60, 61, 62, 63, 64, and 65. These wedges are partially lodged within the slot receiving rod member 5a and are welded to their respective slots and to the adjacent section of the rod member. Hence, the substituted wedges serve as rigidly supported bearing surfaces. The above described wedges (30, 31, 32, 33 and 34) attached to and extending from split section 25 bear against respective ones of wedges 60, 61, 62, 63, 64 and 65. The operation and utility of the wire come-along illustrated in FIGS. 4 and 5 is duplicative of that described with respect to FIGS. 1, 2, and 3.

In conclusion, the wire come-along is attachable to a wire or cable of almost any size and the cable may be formed of hard or soft material. It is easily manually attachable or detachable from any cable without the use of any tools. The clamping forces exerted by the wire come-along are distributed over a substantial circumferential surface area to inhibit damage due to concentrated clamping forces or discontinuous non-uniformly applied clamping forces. Because of its capability for utilizing inserts to accommodate a range of cable sizes, the wire come-along has a degree of universality not previously available.

While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, elements, materials, and components, used in the practice of the invention which are particularly adapted for specific environments and operating requirements without departing from those principles.