| 摘要 |
709,271. Ammeters and voltmeters. ALTENBACH, F. Dec. 29, 1950, [Dec. 31, 1949.] No, 31602/50. Class 37. A portable apparatus for testing storage batteries comprises a handle, a voltmeter, an ammeter, and a pair of pointed prongs secured to the handle, a variable resistor secured to the apparatus, a direct connection between the prongs and the voltmeter, and a connection through the resistor between the prongs and the ammeter. Secured to the lower end of an insulating handle i is a pair of pointed metal prongs 2, 3 providing a fork. The prongs 2, 3 are connected by cables 28, 29 to a voltmeter 10 secured to the upper end of the handle 1. Retained between the prongs 2, 3 by means of brackets 30, 32 is a variable resistor composed of a pair of gunmetal discs 17, 18 interleaved with a number of discs 19 of carbon or other resistive material. The bracket 30 is insulated from the prong 2. Projecting centrally through the discs 19 is a stud 33 screwed into the disc 18 and insulated from the discs 17, 19 by a sleeve 34. The stud 33 is rigid with a control knob 9 of insulating material, by which it can be rotated. In the movable disc 17 and arranged around the stud 38, not shown in Fig. 1, are pushes 35 of insulating material which are outwardly pressed by springs 36 so that when the knob 9 is turned to screw the stud out from the disc 18 the disc 17 is lifted and breaks contact with the discs 19. Cables attached to thimbles 39, 45 are connected to the shunt of an ammeter (not shown) carried by the handle 1. |
