GB754230A - A maximum demand mechanism - Google Patents

Abstract

754,230. Speedometers. LANDIS & GYR AKT.-GES. Feb. 10, 1954 [Feb. 14, 1953], No. 3958/54. Class 106 (3). A maximum demand mechanism comprises a resetting device which effects decoupling of the meter drive, at the end of a registration period and re-coupling directly zeroization has been effected. In one example, Fig. 2, the meter (not shown) drives the indicating drum 61 through the gears 2, 3, 4, 5, a friction coupling 52, 53, a shaft 50 and a differential gear 54, 55, 56, the carrier 56 of which is integral with the drum 61. The drum 61 is connected through gearing to a pointer 66 which moves over a scale 67. The shaft 50 also drives a resettable pointer 45 through the gears 6, 40, 41, 7, 42, 43, 44. The gear 7 is rotatably mounted on a spindle 13 and is integral with a disc 14 having a tooth 15. Also free on the spindle 13 is a disc 16 having two spaced teeth 17, 18. The tooth 17 is normally engaged by a pawl member 28 carried by a lever 26 fixed to the spindle 13. The tooth 18 is normally engaged under the pressure of a spring 19 by a pin 47 carried by a lever 26 freely pivoted on the spindle 13 and movable between two positions determined by the pins 23, 24. The lever 21 carries the shaft supporting the gears 3 and 4 and during a registration period the lever 21 is held by a spring 22 in the position in which the gear 4 meshes with the gear 5. At the end of a registering period the electromagnet 12 is energized, its armature 31 rotates clockwise and through the gears 33, 34 drives the spindle 13 and its arm 26 counterclockwise. The pawl 28 rotates the disc 16 and the spring 19 pulls the lever 21 counter-clockwise to abut the pin 24 and withdraw gear 4 from gear 5. As the lever 26 continues to rotate a pawl 27 carried thereby meets the tooth 15 and rotates the disc 14 and the pointer 45 back to zero whereupon a stop 29 disengages the pawls 27, 28 and the spring 19 returns the lever 21 to recouple gears 4 and 5. In another example, Fig. 1 (not shown), the drum 61 and its driving mechanism are omitted and only a maximum demand pointer is provided.