Patent GB-190704425-A (GB)
Title: Improvements in and relating to Time Limit Electric Circuit Breakers.
Inventor: SCOTT WILLIAM MAXWELL
Filed: 1907-02-22
Granted: 1908-02-22
Abstract: 4425. Scott, W. M. Feb. 22. Cut-outs ; switches.-A start-delaying device of the type described in Specification No. 16,846, A.D. 1904, for the electro magnetic tripping- mechanism of an electric circuit-breaker, is so constructed that the extent of the area of the juxtaposed sucker surfaces may be varied in order to vary the time limit, while the juxtaposed surfaces themselves are roughened in order to secure uniformity of action. A rod 41 carries a rod 44 pivotally supporting a ring 45, which in turn pivotally supports a sucker member 47 by ears 46, the member 47 therefore being supported upon a universal joint. The member 47 has raised sectors 51, which are roughened or sand-blasted and engage similar raised sectors 48 formed in the bottom of the sucker-cup 49. A layer of oil is placed between the sucker members. The force necessary to separate the sucker members, and hence the time limit, may be adjusted by varying - hence the time limit; may be adjusted by varying- the amount of overlapping of the sectors, for example by turning the cup 49 relatively to the member 47 by means of a handle 72. The'value of the current strength at wtich the cut-out will operate may be varied by altering the distance between the armature 34 and the magnet poles, 35. This variation is obtained by mounting the cup 49 in a stirrup 56 provided with projections 57 adapted to slide in elongated slots 58 The stirrup 56 is supported by rods 60 pivoted to arms 62, which are in turn pivoted at the point 33. The outer ends of the arms 62 are connected by a plate 63 secured to a plate 63<1>. The plate 63<1> is curved in an arc whose centre is at the point 33, and is proan arc whose centre is at the point 33, and is provided with an inclined slot 64, which is engaged by a pin 69. By sliding the pin 69 along an horizontal calibrated slot 66 in the plate 65, the vessel 49 is raised or lowered and the distance between the armature 34 and the electro-magnet 35 varied. The invention is described in connexion with a toggle switch having an electro-magnetic trip. An arm 5, pivoted at the point 6, carries a laminated bridging-member 4 and movable shunt contacts 9, 14. The arm 5 is operated by a handle 17, pivoted at the point 18 and provided with a projection 22. connected to a toggle-link 20. The member 4'is held in its ' on' position by a latch 25, pivoted at the point 26 and pressed upwards by means of a spring 27. A lever 28, pivoted at 26, has an adjustable screw 29 at one end, which engages with the latch 25, and a tail 30 adapted to engage with a lever 31. The lever 31, pivoted at the point 33, is operated by the armature 34 of the electro-magnet 35. When the current in the coils 36 of the electro-magnet 35 exceeds a predetermined value, the armature 34 is attracted ; the lever 31 engages with the tail-piece 30, the latch 25 being tripped by the lever 28 and the circuit opened. The armature frame 32 is provided-with arms 38, between which is pivoted a bar 39 carrying the rod 41 of the start-delaying device