GB740198A - Improvements in or relating to chart hubs for recording instruments - Google Patents

Abstract

740,198. Recording-apparatus. FOXBOROYOXALL, Ltd. Jan. 27, 1954, No. 2506/54. Class 106 (4). A hub for a record chart 10 with a central hole includes a base 1, against which the central part of the chart 10 is clamped by resilient means when flared outwards by interaction with a cam forming an integral and permanent part of extension means 5 which form an integral and permanent part of the base 1. The base 1 is threaded on a clock spindle 2 and bears against a flange 3 thereof. The spindle 2 is tubular and the winding arbor 4 projects therethrough well clearing the tubular extension 5 so that a key can be inserted to wind the clock without affecting the spindle 2, hub 1 or associated parts. A sleeve 6 is slidably mounted on an outer cylindrical portion 5a of the extension 5 where it is retained by a flange 7. The sleeve 6 comprises an inner ring 6a formed with a tube 6b on which an outer ring 6c is mounted, being retained thereon by its rounded end engaging a flared part of the tube 6b. The ring 6c clamps three leaf-springs 8 to the tube 6a which has three equi-spaced longitudinal grooves 6d to accommodate them. After placing a chart over the sleeve 6 and springs 8 in the position shown in Fig. 1 the sleeve 6 is moved towards the position of Fig. 2 and balls 9, welded in dimples in the springs 8, ride up inclined cam surfaces 5b and down surfaces 5c until the tips of the springs, which may be slightly concave, engage the chart 10, the inward radial pressure having a clamping effect. An annular insert 12 of plastic material, e.g. polythene or the material known under the Registered Trade Mark " Alkathene ", presents a smooth surface to the chart facilitating adjustment relative to the hub by turning the sleeve 6. Specification 631,264 is referred to.