GB571141A - A new or improved device for testing fuses - Google Patents

Abstract

571,141. Indicating faults; fuse bases. DELAPRE COMPONENTS, Ltd., STEVENS, R. J., MAJOR, P. C., and BARRON, B. S. Jan. 31, 1944, No. 1752. [Classes 37 and 38 (i)] [Also in Group XYXVII] Apparatus for testing fuses of the cartridge or of the slide-locking type comprises a box containing contacts with which either type of fuse may be engaged, an indicating lamp, and an isolating switch which is closed only when the door of the box is closed. The box 10, Fig. 4, is divided by a removable partition 15, into two compartments. In the left-hand compartment is an inclined V-trough 16 having upper and lower side contact plates 18, 19, with which the end contacts of a cartridge fuse may be engaged, and a lower contact 30 and a sliding spring-mounted upper contact 29b between which the contacts of a fuse of the slide-locking type may be gripped. The testing contacts are connected in series with an indicating lamp 17, in the right-hand compartment of the box, and with an isolating switch 39 of the telephone jack type. This switch is closed by a jack plug 51 when the hinged door 11 of the box is closed, thereby closing the testing circuit and causing the lamp to light if the fuse is intact. A window 52 in the door 11 enables the lamp 17 to be observed.. A push-button switch 53 enables the lamp 17 to be connected directly across the mains for checking the soundness of the bulb. On the inner face of the door 11 is a wedge 57 which can slide on a rod 58 against a spring 59. When the door is closed this wedge presses the fuse against the testing contacts. A socket 60 is provided for cartridge fuses of very small sizes, the circuit being closed by a spring contact 63 carried by the door 11. In a modification the switches 39, 53 are replaced by a single switch, Fig. 10, comprising a rotatable member 73 carrying a pair of contacts 77, 78 which co-operate with brushes 79, 80, 81. When the door is open the switch is in the position shown, in which the contacts 77, 78 are clear of the brushes. The member 73 may be rotated clockwise by a finger-piece 82 so that the contact 77 bridges the brushes 79 and the contact 78 bridges the brushes 80, thereby completing the lamp-testing circuit. Counterclockwise rotation is prevented by a pawl 87 which is moved into a detent 90 by a plunger 84 pressed rearwardly by a tailpiece 83 on the open door 11. When the door is closed the pawl 87 is moved out of the detent and the member 73 is moved counterclockwise by a wedge on the inner face of the door engaging beneath the finger-piece 82. The contact 77 then bridges the brushes 80 and the contact 78 bridges the brushes 81. closing the fuse-testing circuit.