Ladder-type cable supports are used for supporting electric cables, especially in cases where several cables run side by side over a shorter or longer distance. For convenience, ladder-type cable supports are hereinafter termed cable ladders.

As the term suggests, a cable ladder is a ladder-like structure and thus comprises a pair of parallel side rails (stiles) and rungs interconnecting the side rails. A cable ladder may be mounted in upright or horizontal position; in the latter case the rungs may be horizontal or vertical.

Regardless of whether the cable ladder is upright or horizontal, the cables have to be secured to it. The currently predominant way of securing the cables consists in tying or lashing them individually to the rungs using wire. This way of securing the cables is time-consuming and, accordingly, costly.

The object of the invention is to provide a simple device by which cables can easily and quickly be secured to a cable ladder. According to the invention, this object is achieved by a clamp having the features set forth in the independent claim. Features of advantageous embodiments of the device according to the invention are set forth in the dependent claims. An exemplary embodiπent of the invention is shown in the accompanying drawings and is described hereinafter with reference thereto.

Fig. 1 is a cross-sectional view of a cable ladder on which cables are laid and secured by means of a clamp embodying the invention;

Fig. 2 is a lateral view, partly in section along line II-II in Fig. 1, of a short length of the cable ladder shown in Fig. 1.

Figs. 3 and 4 are representations corresponding to portions of Figs. 1 and 2 and show a modified design of clamping bars forming part of the clamp according to the invention.

The illustrated cable ladder K is of conventional design comprising two tubular parallel side rails (stiles)

S of polygonal cross-section and parallel rungs P inter¬ connecting the side rails, the rungs being in the shape of tubes of circular cross-section which are passed through the side rails and fixedly secured to them. The entire ladder is made of light metal.

Laid on and secured to the cable ladder K are a number of parallel electric cables arranged in two layers El and E2. A clamp 10 which forms the subject matter of the present invention is used for securing the cables. Only a single clamp 10 is shown in the drawings, but it will be understood that several clamps are mounted at suitable intervals on the ladder.

The clamp 10 is mounted on the cable ladder K adja¬ cent a rung P and, more particularly, is held on both the rung P and the side rails S. It comprises a pair of holders 11A and 11B, which are engaged with respective ones of the side rails S and with the rung P, and a pair of parallel clamping bars 12 and 13 which are mounted on the holders and extend along the rung and which serve to clamp the cables El and E2.

Each holder 11A, 11B comprises a trough-shaped hook portion 14 which hooks on one longitudinal side or edge Sl of the associated side rail S. Joined with the upper edge of the inner wall 14A, 14B of the hook portion is a flat rectangular plate 15 which is positioned immediately below one side of the rung P (the underside when viewing the ladder as in Figs. 1 and 2) .

Secured to the plate 15 is a retaining member formed by a leaf spring 16, one end of which is fastened to the plate, by welding or otherwise, adjacent one of the trans¬ verse edges thereof and which extends in cantilever arch fashion above the plate towards the opposite transverse edge thereof, see Fig. 2. The longitudinal centre plane 16A of the leaf spring 16 is generally parallel to the longitu- dinal centre plane 14C of the trough-shaped hook portion 14; when the clamp is mounted on the cable ladder K, the centre plane 14C coincides with the centre plane of the side rail S.

Secured to the plate 15, adjacent the transverse edge where the leaf spring 16 is secured, is also a screw-thread tie rod 17, one end of which is fastened, by welding or otherwise, to the plate and which extends transversely to the plane of the plate from the side of the plate where the cantilever portion of the leaf spring is situated, that is, upwardly when viewed as in Figs. 1 and 2.

In the illustrated embodiment, the two clamping bars 12 and 13 are of rectangular cross-section and may be made of plastics, for example. At their ends they have recesses in the shape of elongated holes or slots 12A and 13A, respectively, through which the tie rods 17 pass. On opposite sides of the inner clamping bar 12, that is, the clamping bar which is closest to the rung P, a number of transverse recesses 12A, 12B for the cables El and E2 are provided. The outer clamping bar 13 is smooth.

At the outer side of the outer clamping bar 13, each tie rod 17 has a clamping member 18 in the shape of a wing nut with an associated washer 19. When the clamp 10 is to be mounted on the cable ladder K, the holders 11A, 11B are first engaged with the side rails S adjacent the rung P by their hook portions 14 whereupon the holders are displaced along the side rails until their leaf springs 16 have slid over the side of the rung facing the cables so that the holders take the posi¬ tion shown in Figs. 1 and 2, in which they are held by themselves to the cable ladder.

Thereupon, the clamping bars 12 and 13 are positioned on the tie rods 17 of the holders, and as a final step the clamping members 18 formed by the wing nuts are applied and tightened so that the cables El are clamped between the clamping bar 12 and the rung P and the cables E2 are clamped between the clamping bars 12 and 13.

In the embodiment shown in Figs. 3 and 4 the clamping bars 12' and 13' do not have the cable recesses shown in Figs. 1 and 2. Instead, the clamping bar 12' is provided with releasably mounted adapters in the shape of slide blocks 112 of a height matching the diameter of the cables such that the upper side of the cable layer E2 is in a

plane parallel to the underlying clamp bar 12'. On the upper side thereof the slide blocks 112 have recesses 112A resembling the recesses 12A of Figs. 1 and 2.

As is apparent from the foregoing description and the figures of the drawings, the clamp 10 consists of simple and inexpensive components and can be mounted very quickly and without difficulty.

It will be appreciated that the invention is not limited to the illustrated embodiment which is shown only by way of example.