GB213916A - Improvements in door closing and check mechanism - Google Patents

Abstract

213,916. Weeks, W. W. April 3, 1923, [Convention date]. Operating doors by lever mechanism and by springs; checks. - In a piston check, the controlling fluid is discharged freely from the cylinder to a chamber connected with the cylinder during the up-stroke of the piston, additional passageways being provided in the walls of the cylinder for returning the fluid to the lower side of the piston, a restricted by-pass also being provided to control the flow of fluid from the lower end of the cylinder to cushion the piston in its downward stroke. The spring and check cylinders are vertically arranged or inclined, as shown, in order to maintain the check cylinder filled with oil and to avoid the use of packing. The door closing-spring 32 abuts at one end against a sleeve 36 on the piston-rrod 20, and the downward movement of the member 36 is limited by stop pieces 40 in order to maintain a passage above the open end of the member 12 for the free movement of oil. As the door is being moved into the open position, oil passes freely into the chamber 34 and through the by-pass 26 to the underside of the piston 18 until the piston is above the upper end of the passage 26; oil can then pass round the piston through grooves 30 in the walls of the check cylinder. When the door is released and is being closed by the spring 32, it closes freely until the check piston reaches the upper end of the restricted passage 26. The spring 20 has coils that diminish gradually in diameter and pitch to avoid the spring coils buckling under strain. The lower end 18<1> of the check piston is tapered, as shown. In Fig. 1, a door such as a sliding door of a lift is provided with the combined closing-spring and door check connected to a pair of toggle-levers 4, 3 operable by a hand-lever 8 pivotally mounted on the door 1.