Patent GB-1292104-A (GB)
Title: Improvements in or relating to door assemblies
Inventor: STRONG REGINALD JOHN HENRY
IPC: E05F15/10
Filed: 1970-03-16
Abstract: 1292104 Door operating mechanism WESTLAND ENGS Ltd 19 April 1971 [16 March 1970 3 July 1970] 12491/70 and 32298/70 Headings E2A and E2M In a door assembly, the closure member may be operated both manually and by a power-operated mechanism, the power for the latter being supplied by a motor rotating in one direction only. Provision is made for disconnecting the closure member from the power mechanism in the event of the member being obstructed whilst being opened or closed. Fig. 1 illustrates a mechanism for producing linear reciprocating motion by means of a unidirectional reciprocating motor. The motor (not shown) drives one or both of the sprockets 21 around which chain 20 is passed. One of the links of the chain is replaced by plate 22 to which is attached link plate 25 at the pivot 23; this pivot being on the line joining the centres of sprockets 21. As the chain rotates pivot 23 reciprocates along this line of centres, pausing between changes of direction as the plate 21 turns through 180‹ around the sprocket. Figs. 2 and 4 illustrate the use of such a mechanism to power an "up-and-over" door. The door closure member 26 runs in tracks 27 on the side walls and is attached to suspension arms 28 which are pivoted at 29 and also attached to counter balance spring 30. The door is attached by bracket 49 and eye-bolt 48 to the trolley assembly 32 which is moved along track assembly 33 by means of a mechanism of the type illustrated in Fig. 1 installed inside the track 36. Each sprocket 21 is mounted on a shaft 37 which is attached through bearing 38 to the track 36. The chain 20 carries a plate 22 to which the pivot pin is affixed to lie along the line of centres of the sprockets. The pivot pin here takes the form of a bobbin-shaped drive pin 40 which projects from the track and serves to drive the trolley assembly 32 and hence the door. As illustrated in Figs. 4 and 5 the trolley assembly 32 runs on rollers 42 on the outside of track 36 and consists essentially of plungers 43, which entrap the drive pin 40 through being forced down by springs 44, chassis 41 and bar 47 through which eye-bolt 44 is threaded so long as plungers 43 entrap drive pin 40, the power mechanism can operate the door, but if the pin 40 can escape from this entrapment, the drive will be disconnected from the door. This happens when the door is impeded in motion, thus halting trolley assembly 32 and forcing the pin 40 hard against one of the plungers 43. Since the plungers are shaped as illustrated and, since their tips do not project below the centre line of pin 40, the pin 40 will force the plunger 43 up against the tension of spring 44 and will consequently escape, and will continue its motion along with the driven chain 20. The drive is reconnected to the trolley assembly more easily than it is disconnected since the shape of plungers 43 allow them to be lifted by the pin from the outside of the pin trap then from the inside, consequently when the pin is driven back after its release the door is reconnected to the drive. Fig. 7 (not shown) illustrates alternative types of safety release mechanism. Means are provided for securing an "up- and-over" door by which manual operation is prevented, but powered operation is possible. As shown in Fig. 8, the door is held shut by latches 60, which cooperate with side frame members of the door frame. Manual operation of the door is prevented by locking the lock 63, but the latches 60 can be withdrawn by the power unit by means of cables 65, 64 and 61. Cable 65 is attached to bolt 66 on the trolley assembly 32. In operation, the power unit drives the trolley assembly 32 away from the door 26, firstly withdrawing latches 60 to free the door and then when the assembly 32 reaches the further of the nuts 57 an ring-bolt 48, opening the door so overiding the lock 63 which would prevent manual opening. The use of the invention to operate doors which slide vertically and horizontally is disclosed.