GB2255066A - Foldable coupling means with sprung take up for slack cable - Google Patents

Abstract

A printed circuit board extender FIG 2 is in the form of a foldable planar coupling means 4, 8, which has a pivot means 10 along a fold line substantially in the plane of the coupling means, connecting fibre optic cables 12 extending across the line of the pivot means, and cable control means each including an axially slidable cable clamp, 20, FIG 4, spring means 28 for controlling the axial movement thereof and arranged to remove the slack occurring in the portion of the cable extending across the line of the pivot means as the coupling folds. <IMAGE>

Description

CABLE RETRACTION DEVICE The present invention relates to a device concerned with the protection of cables, particularly but not exclusively fibre-optic cables, from damage due to flexure.

In an equipment rack for telecommunications systems it is frequently necessary to make it possible to obtain access to one or more printed circuit boards in the rack for testing and maintenance to be carried out.

It is well known to use "extender boards" which slide into the rack and engage the appropriate printed circuit board connectors normally receiving the printed circuit board to which it is required to have access. The relevant printed circuit board is then plugged into the extender board so as to stand proud of the rack.

Such an arrangement, however, gives rise to problems when access to more than one printed circuit board is required at any one time as their is frequently insufficient space between the boards to provide the necessary access. This can be solved by the use of extender boards which have a pivot provided in the plane of the board to enable the printed circuit boards to be folded through approximately a right angle in either direction to provide the required access clearance. The folding movement brings problems of its own in that any cables which extend across the pivot line are subject to flexing and axial movement.

The risk of damage due to this movement is especially important for fibre-optic cables and air-spaced coaxial cables, but other types of cable may also be at risk.

The aim of the present invention is to minimise the risk of damage to such cables.

According to the present invention there is provided a planar coupling means comprising a pivot means along a line substantially in the plane of the coupling means, a connecting cable extending across the line of the pivot means, and cable control means including an axially slidable cable clamp, spring means for controlling the axial movement thereof and arranged to remove the slack occurring in the portion of the cable extending across the line of the pivot means.

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which : Figure 1 shows a view in the plane of the printed circuit boards of a telecommunications system equipment rack, including a pivoting extender board; Figure 2 shows a perspective view of an extender board incorporating the present invention; Figure 3 shows an exploded perspective view of the cable control means of the present invention; Figure 4 shows a part sectional view of the cable control means when assembled, viewed radially in the plane of the printed circuit board.

Referring to Figure 1, a telecommunications equipment rack 2 is shown. An extender board 4 engages a printed circuit board connector 6 and has a projecting section 8 pivoted on the extender board 4 at a pivot 10. Due to this pivoting facility the section 8 can be moved between positions 8a and 8b, shown by dotted lines.

In Figure 2 the extender board 4 is shown in greater detail. Fibre optic cables 12 extend between connectors 14 on the extender board 4 and connectors 16 on the section 8. The fibre optic cables 12 are controlled by cable control means 18.

The cable control means 18 is shown in greater detail in Figures 3 and 4. The cables 12 are held in V-shaped grooves 22 in a cable clamp 20 by a plastic tie 24 augmented by the application of an adhesive. The clamp 20 slides on a rod 26, and is pushed to one end of the rod 26 by a spring 28. The rod 26 is retained by end blocks 30 on the board 4 using screws 32.

As the section 8 is moved from the position 8b towards the postion 8a the fibre optic cables 12 are placed in tension and the cable clamp 20 slide on the rods 26 compressing the springs 28.

When the section 8 is returned towards the position 8b the pressure of the springs 28 removes the slack created in the cables 12 avoiding kinking of the cables 12. To control the cables passing across the extender board a cover plate (not shown) may be fitted.

Obviously, various changes may be made to the details of the construction without departing from the basic idea of the present invention.

Claims (3)

1. A planar coupling means comprising a pivot means along a line substantially in the plane of the coupling means, a connecting cable extending across the line of the pivot means, and cable control means including an axially slidable cable clamp, spring means for controlling the axial movement thereof and arranged to remove the slack occurring in the portion of the cable extending across the line of the pivot means.

2. A coupling means as claimed in Claim 1, wherein the conecting cable is a fibre optic cable.

3. A planar coupling means substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.