Patent GB-734623-A (GB)
Abstract: 734,623. Mechanical relay and follow-up devices. LANDIS & GYR AKT.-GES. Feb. 12, 1953 [Feb. 13, 1952], No. 4023/53. Class 118 (2). A chopper bar regulator of the type having an indicating pointer 3 and adjustable contact feelers 27, for periodical ascertainment by touch of the position of the said pointer 3, and flexible transmission means 32 of the Bowden cable type from the desired value setting device to switch means 28, is characterized in that the sheath of each transmission means abuts at one end 34 against the casing of the regulator and at the other end against a contact feeler 27, the core 33 enclosed in such sheath being fixed at the stationary sheath end to the switch means 28 and at the contact feeler end to a frame 24 of the setting device that is controlled by the chopper bar 14 to be movable up and down independently of the contact feeler, the whole being so arranged that whenever on lifting of the chopper bar 14 the pointer 3 lies in the path of a contact feeler 27 the core 33 of the respective transmission means 32 is pulled along its sheath to operate the switch means 28. The Figure shows only sufficient of the regulator for understanding the invention. The measuring movement 2 having the pointer 3 is carried by a bracket 1 under which is arranged a device for setting the desired value in the form of a flat arm 4 pivotable about the axis of pointer 3 and carrying three contact feelers 27 and a setting pointer 12. A channel-shaped bearing-piece 5 guides the arm 4 around the arcuate front edge of bracket 1. The three contact feelers 27 are slidably carried in a slot 9 in a ledge 7 and they rest on a lower ledge 8, both ledges being secured to the upturned part 6 of the arm 4. The upper ledge 7 is extended over itself in a U-shape to provide an upper part 10 with a slot 11 in which the top ends of feelers 27 may engage when they are raised. The frame member 24, forming part of the setting device assembly, carries pins 26 which slide in holes in the ledges 7 and 8 and in feelers 27. The lower end of frame 24 is U- shaped at 23 to slidably engage the arcuate chopper bar 14 which is pivoted at 15 and periodically lifted by a cam mechanism 18, 20 on a shaft 16 continuously driven by a motor (not shown). The inner cores 33 of the three Bowden cables 32 are attached to the frame 24 and the outer sheaths abut respectively the contact feelers 27. Three mercury switches are provided for the respective contact feelers and are separated from the measuring movement by a wall in the regulator casing. For clarity only one switch, 28, is shown and the wall, to which the ends 34 of the cable sheaths are secured, is not shown. The far ends of inner cores 33 are attached to pivoted levers 29 carrying the switches 28. Each switch 28 is biased into the " off " position by a spring 43 and is latched by a check spring 30 fitted with a stop 42. When the chopper bar 14 is lifted, the frame 24 is raised and cores 33 attached thereto are lifted but there is normally no relative movement between cores and sheaths as the feelers 27 are free to rise also. If, however, the pointer 3 lies in the path of a feeler 27 the pointer is pressed against the part 10 and prevents upward movement of the feeler ; this restrains the respective sheath and the core 33 is then pulled relative thereto. Lever 29 is thereby pulled off spring 30 which springs up behind lever 29 and locks the switch 28 in the " on " position. On further rotation of the shaft 16, towards the end of the next upward movement of the chopper bar 14, a cam 38 engages a pin 40 on a spring-loaded lever 36 pivoted at 37 and a rod 35 is depressed against springs 30. This allows switch 28 to be reset to the " off " position by the spring 43 acting on lever 29 which then comes to rest on stop 42, providing, of course, that the pointer 3 is no longer in the path of the respective feeler 27.