GB1040839A - Adjustable indicator pointers for knobs - Google Patents

Abstract

1,040,839. Indicators for switches. TECH DEL Ltd. March 22, 1965 [March 26, 1964], No. 13047/64. Heading H2B. [Also in Division G1] Indicating-apparatus comprises a pointer 2 fitted to a knob 1 so that one grips the other and the resilience of an annular disc-like portion 7 of the pointer 2 serves to restrain relative rotational movement between the knob 1 and the pointer 2, which has an indicating portion 10 projecting beyond the circular periphery of the disc 7. The knob 1 and the pointer 2 are each moulded in one piece from a synthetic plastic material in which the strain produced in the material if it is stressed up to half the ultimate tensile stress, disappears when the material is relieved of the applied stress. By applying a sufficient relative force between the pointer and knob they can be relatively rotated to set the pointer to the zero point of a scale when the knob has turned a D-sectioned shaft 3, e.g. of a potentiometer to an initial position. In modifications the portion 10 is omitted and either (a) the diameter of the face 9 of the pointer disc 7 is greater than that of the face 5 of the knob and the outer projecting part of the face bears graduations on a single line, or (q) the faces 9, 5 have the same diameter but a part of the knob 1 is cut away to expose graduations on a line inscribed on the outer part of the face 9. To assist the shoulder 8 of the pointer 2 to enter the cylindrical recess 6 of the knob 1, the outer edge 12 is chamfered. The free end of the shoulder 8 may be formed with a circumferential rib to engage a corresponding recess in the surface 6. The knob may be mounted on the shaft of a rotary switch.