Electricity: circuit makers and breakers – Special application – Frangible or destructible type
Patent
1981-08-04
1983-05-24
Grimley, A. T.
Electricity: circuit makers and breakers
Special application
Frangible or destructible type
337409, H01H 3500
Patent
active
043852165
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND AND PRIOR ART
An ultra-quick electric current breaker device is known, wherein an insulating member acting as a punching piston is pushed by a pyrotechnical charge in such manner as to sever a destructible electric conductor. The displacement of this piston is generally transverse with respect to the conductor, but it may also be provided as longitudinal. In such a case the destructible conductor includes an upstream portion having the shape of a socket in which the punching piston slides, the outer side of the bottom of this socket extending as an intermediate portion which is slidably engaged into the bore of a downstream portion disposed at a certain distance from this bottom, the three portions being co-axial with respect to each other. When the charge explodes the punching piston severs the bottom of the socket to separate therefrom the intermediate portion which it pushes into the bore of the downstream portion.
The invention aims at improving the devices of this kind.
THE INVENTION
In accordance with the invention the intermediate portion is integral with the downstream portion with which it is connected by an annular zone of reduced cross-section, so that the whole of the destructible conductor constitutes a unitary member.
The annexed drawing, given by way of example, will permit a better understanding of the invention, of the characteristics which it possesses and of the advantages which it may afford.
THE DRAWINGS
FIG. 1 is a general axial section of a device according to the invention at its normal closed circuit position.
FIG. 2 partially reproduces FIG. 1, but the parts being shown at the open circuit position.
The device illustrated in FIG. 1 comprises a destructible conductor 1 affording the shape of a substantially cylindrical body which may be divided into three portions, namely an upstream portion 1a in the form of a socket, then an intermediate portion 1b the diameter of which is reduced to a considerable extent by an annular groove 1c, and finally a downstream portion 1d having a blind bore 1e with a diameter which is only slightly larger than the diameter of the intermediate portion 1b.
The upstream portion defines a cylindrical inner space, the bottom 1f of which is in the form of a flaring frustum of a cone with a central cylindrical depression 1g of small depth having a diameter which is slightly smaller than the diameter of the intermediate portion 1b. The arrangement is such that this depression only leaves a remaining connecting zone 1h of small cross-section between this portion 1b and the upstream portion 1a.
In the same manner, the bottom of the blind bore 1e of the downstream portion 1d only leaves between this portion and the intermediate portion 1b a connecting zone 1i having a relatively small cross-section.
The wall of the inner cylindrical space of the upstream portion 1a is covered by a sleeve 2 of small thickness made of an insulating material. A piston 3 made of a non-thermoplastic stratified insulating material having a high mechanical strength is slidably mounted in this sleeve, the side of this piston which faces the bottom of the space being shaped in such manner as to correspond to the profile of this bottom, namely with a frusto-conical surface 3a and a cylindrical central boss 3b, being however noted that the length of this boss is noticeably greater than the depth of the depression 1g. The piston 3 is normally fully pushed towards the left in such manner that its boss 3b engages the bottom of the depression. An empty space 4 of noticeable width is thus left between the facing frusto-conical surfaces of the bottom of portion 1a and of this piston 3.
The side of piston 3 opposed to boss 3b is formed with a blind bore 3c into which one of the ends of a pyrotechnical motor 5 is engaged. This motor comprises a main metallic body 5a which contains the pyrotechnical charge proper, a piston 5b which projects from this body to reach the bottom of the blind bore 3c, and at its opposed end a head with which the electric firing conductors 6 are connecte
REFERENCES:
patent: 2816196 (1957-12-01), Daudelin
patent: 3264438 (1966-08-01), Gay
Miyoshi, Fukushima, Ultra-high Speed Protection Device, Fuji Ultrup Fuse, Fuji Electric Review, vol. 18, No. 1, pp. 49-51, 1972.
A paper recommended and approved by the IEEE Switchgear Committee of the IEEE Power Engineering Society for presentation at the IEEE PES Summer Meeting, Portland, OR, Jul. 18-23, 1976.
Ginsburg Morris
Grimley A. T.
Lucien Ferraz & Cie
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