GB1044168A - Door closers - Google Patents

Abstract

1,044,168. Door closers. JOSIAH PARKES & SONS Ltd., D. S. MAITLAND and G. L. TREDWELL. Feb. 15, 1965 [Nov. 15, 1963], No. 45134/63. Heading E2M. In a door closer for swing doors in which a check device is arranged between an actuating member such as the rotary cam 15 and a spring means such as 26 for loading the actuating member, the check device comprises a pair of piston assemblies each comprising a pair of pistons 12, 13, slidable in an associated bore 11 and urged apart by resilient means 14, each assembly being provided with one-way valves 33 to admit hydraulic fluid to the space between the pistons and restricted passage means 34 to allow the fluid to escape gradually from the said space. The cam 15 is connected by its spindle 17 to a swing door at the rotational axis thereof. A pair of follower arms 18 pivoted about a fixed common pivot 19, have rollers 20, 21 for engaging the cam 15 and the pistons 12. The pistons 13 are engaged by abutments 22, one of which is adjustable and which are carried on a slide member 23 having a tubular stem 24 sliding in a central bore and housing a spring 26 acting between an annular abutment 27 and an abutment 28 adjustable on a tension rod 29 anchored at 19. As the cam 15 is turned clockwise from the door closed position in Fig. 1, the right-hand piston assembly acts as a rigid member on the slide member 23 to load the spring 26, whilst the pistons of the other assembly move apart and fluid enters the space between them. On releasing the door the slide 23 moves upwards tending to close the door, and the left-hand pistons at first move upwards in spaced relation but as the cam approaches the door-closed position the left-hand pistons approach each other and the fluid is gradually expelled from the interspace through the bleed port 34. Grooves 36 on the pistons 12 allow fluid to escape after the lower end of the piston 12 passes the bleed port 34. The cam 15 may be rotated through a further 90 degrees from the 90 degrees open position, such motion being restricted by the pistons of the left-hand assembly being forced together against the action of the fluid present in the interspace. The cam 15 and the arms 18 are arranged so that the door is retained in the 90 degrees and 180 degrees open positions until a closing movement is initiated by hand. Relief ports 37 in the bore 11 prevent overloading if the door is forcibly closed or further opened from the 90 degrees open position.