Patent GB-370557-A (GB)
Title: Improvements in or relating to indicating instruments used in connection with electrically actuated indicators
IPC: G05D13/00
Filed: 1931-02-09
Abstract: 370,557. Indicating instrument for regulators. JACKSON, L. MELLEBSH-, 28, Southampton Buildings, London.-(Siemens-Schuckertwerke Akt.-Ges..; Siemensstadt, Berlin.) Feb. 9, 1931, No. 4074. [Class 135.] A regulating arrangement in which the regulating member is actuated by an electric motor controlled by contacts on an indicating instrument acting through relays, has . the pointer of the indicating instrument adapted to work between a pair of normally stationary contacts, means being provided so that when the indicating contact engages a normally stationary contact, the latter is moved away to break contact but returns automatically to its normal position after a predetermined time interval. In the form shown in Fig. 1, the indicating instrument comprises a.pressure gauge 1 having a pointer 3 with a contact bead 4 adapted to work between a pair of contacts mounted an adjustable distance apart on a carrier 5 pivoted coaxially with the pointer. The carrier is connected by levers and links to a cylinder 16 normally held in a central position by springs 23 pressing abutments 231 against a stop 24. The cylinder is partly filled with oil and has a piston 15 with an adjustable leak 21 adapted to be moved by an auxiliary electric motor 13 adapted to be rotated both with respect to speed and direction of rotation in agreement with the motor operating the regulator. On contact being made, the motor 13 moves the piston which in turn moves the cylinder against the action of one or other of the springs 23 to move the contact carrier. The stressed spring returns the carrier to its normal position at a rate dependent. on the rate at which oil can pass through the restriction 21. In a modification the cylinder is connected to the carrier through bevel differential gear also adapted to be operated by a further auxiliary motor to adjust the normal position of the contact carrier. In the form shown in Fig. 7, the displacing and resetting mechanism comprises a pair of cylinders connected in a closed circuit with a toothed wheel oil pump driven by the auxiliary motor 62. Each cylinder contains a piston adapted to be held in a normal position by springs 90 bearing against abutments 89 provided with stop rods 91 and connected to one another by rods 67, 68, links 69, 70, and an equal armed lever 72 pivoted at 71. The contact carrier 83 has a pinion 80 engaging a toothed quadrant 76 mounted on a cranked lever 74 linked to the piston rod 68 and carried by an adjusting lever 78. The lever 78 is pivoted coaxially with the carrier and is moved by a screw 96 to adjust the normal position of the carrier. The equalizing connection 95 between the cylinders is controlled by a valve 94 linked to an arm 92 on the shaft of the lever 72 so that as the pistons become further displaced from their normal positions the resetting interval is reduced and in the limit continuous contact is maintained. In a modification of this form each normally stationary contact is separately displaced and reset after contact by the movements of the spring abutments 89. The contact for the time being unadjusted may be moved by and in the same direction as, the one being adjusted after the latter has moved through a predetermined angle.