| 摘要 |
<p>978,967. Dashpots. C. C. BLOM. Jan. 10, 1963 [Jan. 11, 1962], No. 1227/63. Heading F2S. [Also in Division E2]. An overhead door-closer adapted to be mounted in the lintel of a door frame comprises a housing 11, a shaft 7 adapted to engage in a polygonal socket in the door and carrying a cam 16, a pair of bars 25, 26 slidably mounted in the housing and connected by a bracket 21, 22 having abutments, e.g. rollers 19, 20, 35, to co-operate with the cam, a yoke. 38 connecting one end of one bar to the adjacent end of the other bar, springs 49, 50 mounted on the bars and tensed between the yoke and a fixed partition 37 in the housing, a piston chamber 48 containing a fluid damping medium, e.g. oil, a piston 47 in the chamber, and a piston rod 40 connecting the piston to the yoke. The rollers and the ends 23, 24 of the bars cooperate with recesses 17, 18 in the cam to hold the door in. the open and closed positions. The piston has a non-return valve 63. During the damping stroke oil flows from the space in front of the piston through channels 57, 56 to a chamber 51 and thence through a port 55 to the space behind the piston, the rate of flow being controlled by an adjustable needle valve 66. A channel 58 communicates with an expansion chamber 59 containing a spring- loaded valve 60 which keeps the oil at a substantially uniform pressure.</p> |
