Patent GB-813400-A (GB)
Title: Improvements in or relating to the testing and grading of electric fuseheads
Filed: 1956-03-29
Abstract: 813,400. Assemblingand testing electric fuseheads. PEARSON, J. D., HERBERT, N., REID, C., MORRISON, B., and IMPERIAL CHEMICAL INDUSTRIES Ltd. Nov. 23, 1957 [March 29, 1956], No. 9874/56. Class 9 (1) Fuseheads comprising two electrodes 3, 3<SP>1</SP> cemented to opposite surfaces of an insulating layer 5 and soldered to a bridge wire are constructed as in Specification 748,675 and graded according to their electrical resistance by the apparatus of Fig. 4, which determines the resistance and directs the tested fuseheads along selected paths according to the resistance. When a comb of fuseheads has been formed it is fed to a reciprocating guillotine 7 which cuts through the electrode 3 into the insulating material 5, partially severing each fusehead. A guide 9 then bends the partly severed fusehead out of the plane of the comb and the resistance is recorded by a device 10. After this a guide 11 bends the fusehead back into line and a reciprocating guillotine 12 severs the fusehead from the comb. The cycle of operations is controlled by a motor-driven cam-shaft (not shown). The combs 14 are placed in slots in a magazine 15, which slides between guides 16 until a sprocket wheel 17 contacts the lowermost comb and feeds it into a guide block 18, sprocket wheels 19, 20, 21 being used to index the comb for each operation. In the first operating position the fusehead rests on an anvil 22 below a knife 23 adjustable in a slide 24. After the knife has cut through electrode 3, a frusto-conical roller 26 attached to sprocket 20 depresses the fusehead, so that electrode 3 is insulated from the remaining fuse-heads in the comb. The fusehead moves to the third position where electrode 3<SP>1</SP> forms a contact between block 18 and a shoe 27, while electrode 3 bridges hinged contacts 28, 29 controlled by springs 30, 31 respectively. The contacts 18, 27, 28, 29 are connected to an alternating current bridge measuring circuit 32 which is adapted to energize a relay 33 or 34 for a resistance range (a) or (b) respectively, e.g. 0.9-1.3 ohms or 1.3-1.6 ohms. If the resistance is below or above both ranges neither relay is energized. Near the end of the fusehead's stay In the third position, a switch 35 closes and if the fuse-head's resistance is in one of the selected ranges the appropriate relay is energized and in turn energizes one coil of a relay 36 or 37. The closing of switch 35 closes a switch 38 to energize the second coil of relay 36 or 37, whereupon switch 35 opens and isolates the relays 33, 34. The relays 36, 37 energize solenoids 39, 40 respectively. These solenoids are connected by linkage to a conduit 41, so that if solenoid 39 is energized the conduit is pivoted about its lower end to allow the severed fusehead to pass into a box 42. Similarly solenoid 40 moves the conduit so that the fusehead passes into a box 43, and when neither solenoid is energized the springs 44 hold the conduit in its mean position, so that rejected fuseheads pass into box 45. After switch 35 opens the fusehead is moved to the fourth position where an anvil 46 guides the fusehead back into alignment with the comb and a knife 47 mounted in slide 24 severs the fusehead, which then falls through funnel 48 into the appropriate box. The waste stub of the comb is fed by sprocket wheel 21 to a receptacle (not shown).