GB621614A - Mechanical movement for a measuring instrument - Google Patents

Abstract

621,614. Indicating-apparatus. WEINGART, R. I. N. Sept. 27, 1945, No. 25065. Convention date, Dec. 13, 1944. [Class 106 (iv)] [Also in Group XXIV] Mechanism for converting rotary movement about one axis into rotary movement about another axis at right-angles, is described in connection with a pressure-responsive instrument, and comprises a cam member 33, Figs. 1 and 3, having a driving edge 35 of an increasing radius which is rotated about a spindle 26 by a connecting link 56 from the pressure-responsive device 50. The edge 35 of this cam co-operates with a spiral groove 22 in a cylindrical member 21 on a shaft 13, 20, the axis of which is disposed in a plane parallel to the plane of the cam 33. Thus rotary movement of the cam 33 converts the linear movement derived from the pressureresponsive device 50 into a rotary movement of shaft 20, which latter carries a pointer 46 to indicate the amount of movement and the degree of pressure acting on the device 50. The lead of the spiral groove 22 may be non- uniform and the contour of the cam 33 varied as required, providing jamming does not occur in the groove. The point at which the link 65 is connected To the cam can be adjusted by means of a slotted link 59 through which the shaft 26 of the cam passes and which is clamped to the cam by a screw 61. The thrust on the cylindrical grooved member 21 is taken by the lower bearing of its spindle 13 and a helical spring 47 is provided to maintain the thrust on this bearing and effect return movement of the mechanism. In a modified arrangement the end thrust on member 21 is taken by a further edge on the cam 33, which may or may not be circular, engaging a conical end on the member 21. Thus the additional thrust edge may modify the rotation imparted to the pointer. In Fig. 8, the driving cam is formed by a strip of metal 79 secured at one end to an arm 78 which may be varied in contour to give the desired movement. In this arrangement also a screw 83 is provided for zero adjustment of the pointer 46 and the shaft 27 of the arm 78 can be adjusted in a slot 82 to further vary the movement transmitted. Specification 557,639 is referred to.