Patent GB-190609789-A (GB)
Title: Improvements in Electric Fusible Cut-outs.
Inventor: PEARD OLIVER LEOPOLD
Filed: 1906-04-26
Granted: 1907-04-25
Abstract: 9789. Peard, O. L. April 26. Cut-outs ; couplings.-Relates to fuses of the type described in Specification No. 20,483, A.D. 1902, in which the wire is gripped inside a strong case as described in Specification No. 5171, A.D. 1906, by terminals such as are described in Specification No. 3784, A.D. 1906, the case being filled with the material described in Specification No. 3783, A.D. 1906. The object of the present invention is to construct terminals which can be manipulated from outside the case to grip the wire inside, to combine the terminals with an indicator, to provide them with a guard-plate facing the fuse, and to provide clogged perforations in the casing to release pressure. In Fig. 4, the insulating lining C is shown extended to form flanges E'. Each terminal tube I, through which the fuse wire passes at each end of the casing, has a screwed extension F', on which is a cap nut by means of which the coned head of the terminal may, by turning the nut, be drawn up into a conical recess in the plug E, which may be of metal. The coned head of the terminal is split crossways so as to contact laterally to grip-the wire. The metal plate O protects the terminal head when the fuse melts. In the arrangement shown in Fig. 6, the terminal tube.is still hollow, but has an ordinary screwthread, and is screwed positively into an insulated metal plug E and against a compressible wire packing R, to nip the fuse wire. The plug E is extended and screwed internally to receive the tube. Instead of being tubular, the terminal may be in the form of a solid spindle I, Fig. 18, with a coned head that is drawn outwardly and spreads a split ring a. The ring is pressed against the flange of an inverted cap Z on a replaceable fuse M, the fuse wire being soldered to the cap. In the arrangement shown in Fig. 19, a simple screw I forces a plug a on to a cap Z to which the wire is soldered; in that shown in Figs. 18 and 19, the replaceable fuse contains the fuse wire and filling-material, and closely fits the outer envelope. The fuse may be combined with indicating-devices operated by pressure when the fuse blows. A piston U, Fig. 8, in a cylinder S screwed to the main case of the fuse, is blown outwardly so that its stem V protrudes. Figs. 11 and 14 show hinged cap indicators. The cap X, Fig. 11, is close fitting, and is forced open by the pressure, and in Fig. 14 a catch y is used. The latter is normally held in locking position by its own spring, but has its spring overcome by the pressure due to the rupture, and then releases a hinged cap which is opened by another spring. Internal pressure, caused by volatilization of the fuse, escapes through a tapering aperture in the casing, the aperture being clogged by plaster of paris or similar powder. One such clogged aperture is shown at X<1>, Fig. 11. To make the fuse gas-tight, the outer case is threaded externally, and engaged by end caps B, Fig. 1, which lie within the material of the flanged insulating bush E, through which the terminals pass. An inner flange is made on the bush, which, when the cap as a whole is screwed on the casing, compresses a packing G against a bearing-surface formed on an extension of the insulating lining C.