Patent GB-434282-A (GB)
Title: Improvements in and relating to automatic circuit breakers
IPC: H01H75/04
Filed: 1934-04-04
Abstract: 434,282. Automatic circuit-breakers; protective cut-out arrangements. SPRIGG, H. H., Northcote Avenue, Killara, near Sydney, Australia. April 4, 1934, No. 10211. Convention date, Feb. 3. [A Specification was laid open to inspection under Sect. 91 of the Acts, Oct. 5, 1934.] [Class 38 (v)] Automatic reclosing mechanism for circuit-breakers comprises a spring 11 capable of being compressed by means of a wire rope or the like 32 wrapped round a pulley 33 which can be rotated by means of a handle 14 placed outside the casing 10 housing the mechanism, ratchet mechanism for retaining energy stored in the spring, trip mechanism operable by the opening of the circuit-breaker for disengaging the members of the ratchet device, and time-delay mechanism for delaying the operation of the reclosing mechanism. In the arrangement shown in Figs. 2 and 3, the casing 10 is mounted on the front wall of the circuit-breaker 8. The spindle 18 of the circuit-breaker carries a member 35 formed with a radial slot 36 which accommodates a ratchet pin 37 carried by a spring-controlled pivoted member 38. A spring 40 biasses the member 35 in an anticlockwise direction. The forward end of the pin 37 normally engages the teeth of a ratchet wheel 42 carried by the pulley 33, a spring- controlled pawl 43 being provided as a detent for the ratchet wheel. When the circuitbreaker opens, a bell-crank lever 23 carried by the indicator spindle 24 operates through push rods 44, 46 and a thrust ball 45 to lift the pin 37 out of engagement with the ratchet wheel 42 and bring the wedge-shaped rear end of the pin into engagement with studs 49 on a pulley 50 connected by a belt 51 with time-delay mechanism 52. The pin and member 35 are then rotated slowly in an anticlockwise direction under the action of the spring 40 until the pin approaches the next tooth of the ratchet, when it falls back into the slot 36 and releases the delay mechanism. At the same time the pin disengages the pawl 43 from the ratchet wheel and the latter is rotated by the spring 11, carrying with it the pin 37 and member 35 and thereby turning the spindle 18 to reclose the circuit-breaker. The pawl 43 then engages the ratchet wheel and a stop 53 engages the member 35 to prevent further clockwise rotation of these members. A pivoted bar 54 adapted to be raised into engagement with a lip formed on the member 35 by means of a cam 55 on a spindle 56 carrying a handle 57, serves as a locking device for the mechanism. In a modification, Figs. 5 and 6 (not shown), the reclosing mechanism is connected by links to the free handle of the circuit-breaker and imparts an arcuate movement to the latter. A suspended weight may be used as the energy storing means instead of the spring 11. The Specification as open to inspection under Sect. 91 comprises also a construction, Fig. 1 (Cancelled), in which no ratchet mechanism is employed. In this construction, the spring 11 is mounted on a rod 15 carrying a piston 13 in a cylinder 12, the rod being connected at one end by a link 16 to a bell-crank lever 17 mounted on the spindle 18 of the circuitbreaker, and at the other end to one of a pair of toggle links 19, 20. When the circuitbreaker opens, a lever 23 mounted on the indicator spindle 24 operates a trip lever 21 to upset the toggle 19, 20, whereupon the spring 11 moves the piston 13 and rod 15 to the right to reclose the circuit-breaker. The movement of the lever 23 is delayed by a dash-pot 26, the extent of the delay being adjustable by means of a thumb-screw 27 which regulates the tension of a spring 28 attached to the lever. This subject-matter does not appear in the Specification as accepted.