An arrangement for regulating the distance between two objects disposed at a variable distance one from the other

摘要

779,812. Automatic control systems. FICKERT, H. March 13, 1953, No. 7096/53. Class 38 (4). In a system in which two members are automatically maintained in light mechanical contact or at a constant distance apart by adjustment of the position of one of them in the appropriate sense by a motor, the motor operates through an electromagnetic clutch controlled by two thermionic switching valves, the grid biases of which are influenced by electrical interaction between the members. In Fig. 1 a cylindrical member 10, the effect of gravity on which is balanced by a weight 5 is moved towards or away from a fixed cylindrical member 11 by energization of an electromagnetic clutch winding 14 or 15 which couples one of two oppositely rotating continuously driven shafts to a rack and pinion moving member 10. The arrangement is such that when members 10 and 11 are not touching, a thermionic valve 9 is conductive to move member 10 towards member 11 but when the members touch, change in the grid bias of a thermionic valve 8 causes the latter to be the conductive valve so that member 10 moves away again. The two valves thus conduct alternately to maintain light mechanical contact between the members. Application to copying devices in machine tools, arc lamp and welding electrode control is referred to. The grid bias of valve 8 may be controlled through an amplifying device by the inductive or capacitative coupling between members 10 and 11 to maintain a predetermined gap between the members.