GB340678A - Improvements in & relating to hydraulic servo-motors - Google Patents

Abstract

340,678. Hydraulic servomotors. COMPAGNIE INTERNATIONALE DES FREINS AUTOMATIQUES, SOC. ANON., 70, Rue Louvrex, Liege, Belgium. Oct. 28, 1929, No. 32731. Convention date, Oct. 27, 1928. Addition to 308,737, [Class 69 (ii), Hydraulic presses &c.]. [Class 69 (ii).] Apparatus of the parent Specification is provided with a valve controlling the exhaust of liquid from a servomotorcylinder, said valve being controlled by a mechanical device which allows it to close when the driven member reaches the desired position. In apparatus for operating electric motor controllers, comprising a reservoir 2, Fig. 1, for liquid under pressure, a reservoir 4 for exhaust liquid, and connected pistons 3a, 3/, in cylinders 3g, 3h, a control lever 7 through contacts a' .. d<t>, 10a .. 10d, 10y completes a circuit including an electromagnet 2k for actuating valves 2a, 4a. On the shaft of the operated member is a cam 13 and an arm 10<1>, with a lost-motion connection with an arm 10<11>, the arm 10<11> co-operating with the contacts 10a .. 10d, 10y, and the arm 10<1> with contacts 10a<1> .. 10d<1>, 10x. As the shaft moves, the arm 10<1> completes the circuit of an electromagnet 12a, which tends to close a valve 12 ; when the shaft reaches the position determined by the position of the lever 7, a finger 13b drops into a notch 13a of the cam 13, so that the valve 12 is allowed to close and holds the parts. In order to allow a gradual closure of the valve 12, the corners of the notches 13a may be rounded. A relay 11 closes a switch 11a when the current passing through the motors exceeds a predetermined value, and completes the circuit of the electromagnets 2k, 12a. The Specification as open to inspection under Sect. 91 (3) (a) comprises apparatus for operating vehicle doors having a valve 15a, Fig. 2 (cancelled), for controlling communication between a cylinder 3g, a reservoir 2 for liquid under pressure, and a reservoir 4 for exhaust liquid ; a valve 12 is closed by its spring when allowed by a cam 13 on a driven shaft, the movement being completed after the closure of the valve 12 by the expansion of air in a reservoir 16, such air having been compressed by the pressure liquid during the first stage of the movement. In the event of obstruction to movement, the increased pressure in the cylinder 3g acts through a diaphragm 17a to close a valve 15b and shut off the supply of pressure liquid. This subjectmatter does not appear in the Specification as accepted.