GB1030870A - Weighing mechanism - Google Patents

Abstract

1,030,870. Dashpots. FISONS FERTILIZERS Ltd. March 20, 1963 [Dec. 22, 1961], No. 45974/61. Heading F2S. [Also in Division G1] In a dashpot for a weighing mechanism (see. Division G1), comprising a piston 1 provided with one-way valves 12, 13 and which works in a pressure cylinder 2 having its upper and lower chambers connected by channels 3, 4 provided with needle valves 5, 6, the channel 4 is also provided with a spring-loaded valve 7 which closes during an upward stroke of the piston 1 after a predetermined pressure in the upper cylinder chamber has been reached so that there is an abrupt increase in damping. The valve 7 comprises a disc 8 which is urged by a spring 9 away from its seating into engagement with a screw stop 11, the lower end of the spring 9 engaging an adjustable bushing 10. The screw 11 may be replaced by a push-rod linked with the mechanism to be damped. In a modification, Fig. II, not shown, a cylinder has a piston with a one-way valve and a central opening which receives a metering pin projecting upwardly from the base of the cylinder, the pin having at its upper end a collar which is only slightly smaller than the opening in the piston so that when they coincide the fluid flow is very much reduced. In a further modification, Fig. III (not shown), a compressible bellows is connected to a reservoir through three channels, one with a non-return valve which prevents flow from the bellows to the reservoir, one with a variable restrictor, and the other with a spring- loaded valve which is generally similar to the valve 7, Fig. 1. In Fig. V (not shown), the damper comprises a cylinder 104 with a piston 101 having through ports 105, 106 with a needle valve 108 and a through channel 109, 110 which has a needle valve 111 and is controlled by a one-way spring-loaded valve 113.