GB634123A - Improvements relating to indicating devices - Google Patents

Abstract

634,123. Indicating-apparatus. BAIRD, Ltd., J. L., JOLLY, R. H. C., and HOLLAND, H. R. May 23,1947, No. 13922. [Class 106 (iv)] [Also in Group XL (c)] An indicating device comprises a system of cords and pulleys connecting a rotary member and a linearly-movable member and includes two cords arranged to be moved respectively with the two members, one cord being attached to a movable pulley or pulleys engaged in a bight or bights of the second cord to give a velocity ratio other than unity between the cords. A spindle 10 of a tuning condenser of a radio-receiver carries a drum 11 around which is wrapped and may be secured a cord 12 whose ends are guided round pulleys 15, 16 and attached to opposite ends of a bar 19 which thus moves longitudinally between limiting positions 19, 191 as the spindle rotates through a limited angle. The bar 19 carries two pulleys 20, 21 and a second cord is anchored at 22 and passes round pulleys 23, 24, 25, 26, 27, 28 and 21 to be anchored at a point 29, the points 22, 29 being beyond the range of movement of the bar 19. A pointer 36 is carried by two parallel lays of the cord in front of a scale 37 and moves at double the speed of the bar 19, In a second embodiment one end of the cord 12 is attached to the drum 11 and to one end of the bar 19 so that the bar is moved in one direction by the drum and in the other by a spring attached to the other end of the bar 19. To keep the second cord taut a tension spring may be inserted between the point 22 and pulley 17. In a modification, see Fig. 3, manual adjustment is effected on a rectilinearly-moving part 39 and an indication is given by rotation of a drum 40 provided with a spiral spring 41. One end of a cord 42 is attached to the drum 40 and the other end to a bar 43 which carries two pulleys in bights of a cord 44. The part 39 may be carried on a single lay as in Fig. 3 or on two parallel lays as in Fig. 1.