Electricity: conductors and insulators – Overhead – Distributing and/or plural point support
Reexamination Certificate
1998-11-27
2001-03-13
Kincaid, Kristine (Department: 2831)
Electricity: conductors and insulators
Overhead
Distributing and/or plural point support
C174S0400CC, C174S041000, C174S042000
Reexamination Certificate
active
06201184
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is generally concerned with suspensions of the type used to support overhead electrical power lines, for example.
It is more particularly directed to the situation in which, forming part of a low-voltage electrical power distribution network, the overhead electrical power line to be supported is formed of four insulated cables twisted together, namely three phase cables and one neutral cable.
2. Description of the Prior Art
The suspensions which support an overhead electrical power line of the above kind at each of the posts between which it runs include a support which is fixed to the post, in the form of a bracket or a hook, for example, and a suspension clamp that is adapted to receive the overhead electrical power line and which is suspended from the support either directly, in particular if the support is a hook, or indirectly, for example by means of a shackle, if it is a bracket.
A suspension of the above type is described in French patent 2 478 246 filed Mar. 13, 1980 as application 80 05609, for example.
As described in the above French patent, the suspension clamp has a top part by means of which it is adapted to be suspended from the corresponding support and a bottom part by means of which it is adapted to receive at least a portion of the overhead electrical power line to be suspended, the bottom part having an open cross-section and forming an elongate cradle below the opening, a clamping system associated with the cradle pivoting about an axis parallel to the lengthwise direction of the cradle.
Until now suspensions of the above type have been used only to support the overhead electrical power line concerned, and not for the drawing operation required to install it.
At present this drawing operation is carried out using pay-out pulleys temporarily attached to the posts, one per post, below the corresponding suspension clamps, and it is only afterwards that the overhead electrical power line is transferred from the pay-out pulleys to the suspension clamps.
The pay-out pulleys used for this operation are dedicated to their function and therefore have an opening yoke which makes them relatively complex and costly.
They therefore require a non-negligible investment for their manufacture and maintenance and they are relatively costly in terms of labour to fit and to remove.
Accordingly, it is desirable to be able to dispense with at least some of the pay-out pulleys, given that those at the ends of the overhead electrical power line to be installed, i.e. that immediately downstream of the pay-out cable drum and that immediately upstream of the drawing capstan, can normally only be conserved.
At present only one of the cables constituting the overhead electrical power line is engaged in the suspension clamp of one of the suspensions, namely its neutral cable, which then serves as a supporting cable for the associated phase cables.
It is now desirable for a suspension clamp of the above kind to be able to receive all of the cables of the overhead electrical power line to be supported.
SUMMARY OF THE INVENTION
The present invention consists in a suspension clamp adapted to receive all of the cables of an overhead electrical power line and suitable for drawing the line so that it can advantageously be substituted for a drawing pulley; it also consists in any suspension including a suspension clamp of the above kind.
The suspension clamp in accordance with the invention is of the kind including a top part adapted to be suspended from a support and a bottom part adapted to receive at least a portion of the overhead electrical power line to be suspended, the bottom part having an open cross-section and below its opening forming an elongate cradle with, associated with the cradle, a clamping system pivoting about an axis parallel to the lengthwise direction of the cradle, characterized in that it includes, in addition to the clamping system, a closing clamp pivoting about an axis parallel to the lengthwise direction of the cradle and adapted to close the cross-section of the bottom part when required, extending from one of the two ends thereof to the other.
The closure clamp provided in accordance with the invention advantageously enables the bottom part of the suspension clamp to be opened, enabling the overhead electrical power line to be paid out to be placed in it, and then the bottom part to be closed before the cable is drawn, preventing the overhead electrical power line that is being drawn escaping unintentionally from the bottom part.
However, unlike a clamping system, the closure clamp in accordance with the invention is advantageously at a distance from the overhead electrical power line during drawing so that the line is entirely free to slide in the manner needed for it to be paid out correctly.
It is only when drawing has been completed that the associated clamping system is operated to hold in position the overhead electrical power line installed in the above manner.
Nesting means are preferably provided in a complementary fashion on the suspension clamp and on the closure clamp for cooperation of the nesting means by relative interengagement with each other when the closure clamp is in the closed position.
Firm and reliable locking of the closure clamp to the suspension clamp in the transverse and longitudinal directions is therefore obtained when the closure clamp is in the closed position through cooperation with a clamping screw controlling the closure clamp, in a manner that is very simple but highly effective.
This makes paying out safe.
The cradle that forms the bottom part of the suspension clamp in accordance with the invention preferably flares outwards at each end to facilitate the paying out of an overhead electrical power line during drawing and for an optimum fit to the inherent shape of the line after drawing, so protecting the overhead electrical power line in both cases.
The suspension clamp in accordance with the invention is preferably made from an insulative synthetic material, as is the shackle that may be used between it and the support from which the combination is suspended, which is beneficial to good insulation of the overhead electrical power line concerned from the support, whilst exploiting relative elasticity of the insulative synthetic material to facilitate the production and/or the fitting of some of the components concerned, which fitting can include snap fastening, for example.
Finally, because it can be suspended from a bracket or from a hook and because its clamping system can adapt to different overhead electrical power line diameters, the suspension clamp in accordance with the invention is advantageously of virtually universal application to a great many different situations.
The features and advantages of the invention will become more apparent in the following description given by way of example and with reference to the accompanying diagrammatic drawings.
REFERENCES:
patent: 3155354 (1964-11-01), Lindsey
patent: 3664620 (1972-05-01), Branum
patent: 3729575 (1973-04-01), Harding et al.
patent: 4113979 (1978-09-01), Torr et al.
patent: 5850056 (1998-12-01), Harwath
patent: 6043433 (2000-03-01), Schweitzer, Jr.
patent: 2478246 (1981-09-01), None
patent: 9426012 (1994-11-01), None
patent: 9707579 (1997-02-01), None
Francois Pierre
Saurina Michel
Kincaid Kristine
Societe Industrielle de Construction d'Appareils et de Mate
Walkenhorst W. David
Young & Thompson
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