Cable-Clamp

The invention relates to a cable-clamp fixture suited for above-ground suspension of a cable, as from a telephone pole.

Current above-ground suspension of communication cable, as for telephone or cable-TV purposes, relies upon a suspension cable, as of stranded steel wire which is tensed in its slings, as from pole to pole, and the communication cable hangs beneath the suspension cable via a series of more closely spaced bails. At each pole connection of the tensed suspension cable, a clamp fixture is set to the tensed cable, and the fixture is anchored to the pole. It has been the practice to employ a clamp-fixture construction involving at least two separate elongate side plates with aligned bolt apertures, one or both plates having one or more elongate narrow stiffening flanges along one or both of its elongate edges. When clamped and pole-mounted, such fixtures serve their purpose of maintaining tension in adjacent slings of the suspension cable, but manipulation of the parts of the fixture during the process of assembly to a cable and to a pole is not as simple as I have discovered that is now possible, with my invention.

It is an object of the invention to provide an improved suspension-cable clamp of the character indicated.

Another object is to provide such a clamp with mechanical features which materially simplify installation.

It is a general object to meet the above objects with a clamp construction which is less expensive to manufacture and to install, and which does not sacrifice clamping efficacy, as compared to existing clamp configurations.

The invention achieves the foregoing objects and certain further features in a one-piece formed sheetmetal clamp construction, wherein two elongate side panels are integrally connected by an elongate single bend, establishing an initially acute angle between the side panels. In one form, the outer longitudinal edge of each panel is characterized by an elongate flange bent inward and generally toward the opposed side panel, at an acute angle to its associated side panel; in another form, the elongate flanges are bent inward to the point of substantially zero angle to the associated side panel. The initial space between flanges is slightly less than the cable diameter to be accommodated, so that cable assembly and loose retention are achieved via snap-action insertion between the flanges. Bolts spanning aligned apertures in the side panels enable secure clamping to, and lug-retention against loss of, an inserted cable.

The invention will be illustratively described in detail in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded view in perspective of a cable-clamp fitting of the invention;

FIG. 2 is an end view of the assembled fitting of FIG. 1;

FIG. 3 is a view similar to FIG. 2, for the cable-clamped condition of the fitting of FIG. 1; and

FIG. 4 is a view similar to FIG. 2, to show a modification.

The article of FIG. 1 comprises a single unitary elongate clamp body 10 of formed stiff sheet metal such as cold-rolled sheet, it being my present preference to fabricate body 10 from coiled strip of width which matches the elongate dimension of body 10. The blank from which body 10 is formed is rectangular, being bent along a central longitudinal alignment to define an upper edge 11 by which two elongate rectangular side panels 12-13 are integrally connected, at an initially acute angle .alpha..sub.1. The lower or outer longitudinal edge of each panel, such as the edge 14 of panel 12, is integrally formed with a re-entrant inturned elongate lug 15, which is initially formed at an acute angle .alpha..sub.2 to the associated side panel (12); the corresponding such lug at the lower edge of side panel 13 is identified 15'.

The angle .alpha..sub.1 may suitably be in the range of 25.degree. to 40.degree. and is preferably about 30.degree., while the angle .alpha..sub.2 may suitably be in the range of 0.degree. to 25.degree. and is preferably about 15.degree., the zero-degree situation being shown in FIG. 4, wherein flanges 15-15' are substantially flattened to their associated panels 12-13. Whatever the angles .alpha..sub.1 and/or .alpha..sub.2, the initial span S between longitudinal flanges 15-15' is preferably slightly less than the effective diameter of the suspension cable to which it is to be assembled and clamped, whereby cable entry past lugs 15-15' involves snap-action and therefore an initial loose retention of assembly to the cable. Further preferably, the inside radius R of the bend 11 is slightly less than half the cable diameter.

The side panels 12-13 have longitudinally spaced bolt apertures 16-17 (16'-17') at corresponding locations, for preassembled loose reception of a clamping bolt 18 and nut 19 at each pair of corresponding bolt apertures 16-16' (17-17'). At their longitudinal center, panels 12-13 have a further pair of corresponding apertures 20-20', for suitably pinned or bolted anchorage to an above-ground support, such as a telephone pole; apertures 20-20' are shown D-shaped, with a short internal lug 20" formed inwardly of the straight edge of each D-shaped opening, and with their respective inturned lugs 20" in longitudinally offset relation. Preferably, transverse stiffening ribs 21 are formed in each of panels 12-13, on opposite sides of each aperture, and bolt apertures 16-17 (16'-17') are square, for keying reference to a carriage bolt 18 at each bolt-clamping location. As shown, a short inward lug 22 along one of the transverse edges of each bolt aperture 16-17 provides further local stiffening action and, as will later appear, provides a transverse positioning limit for cable insertion, it will be understood that a corresponding transverse lug 22' at each bolt aperture 16'-17' in panel 13 may be along the transverse edge which is longitudinally opposite the transverse-edge location for the corresponding lug 22 of panel 12. Lugs 22-22' and 20" are thus provided in longitudinally interlaced relation; and they are preferably of inturned extent short of the ultimately clamped inside separation between panels 12-13.

The described fitting is preferably supplied to the linesman or installer in a loosely assembled relation of nutted bolts 18 to the unitary folded-plate element 10, the size being prescribed for the stated relation between span S and the size of cable 25 to which the fitting is to be clamped. Initial assembly is a simple one-handed snap-action event, followed by pin location to the pole or other support via apertures 20-20'. When the cable has been tensed to assure the desired sling between poles, the completion of each clamp action is again a simple one-handed operation, as by ratchet wrench to each nut 19. When securely clamped, the cable 25 will become locally slightly compressed, as is apparent from FIG. 3, and side panels 12-13 will be in a substantially parallel relation. It will be noted that when thus clamped, lugs 15-15' will have closed the gap S and will have become slightly compressed in a reduction of their angles .alpha..sub.2, but that thus-compressed against each other, lugs 15-15' become a well-reinforced permanent barrier against cable loss.

In a typical clamp configuration, suited for accommodation of 1/4-inch diameter stranded cable, the gap S is 0.225 inch, and the inside radius of the central bend 11 is 0.109 inch.

While the invention has been described in detail for a preferred form, it will be understood that modifications may be made without departure from the scope of the invention.