Patent GB-936320-A (GB)
Title: Concealed overhead door closer
IPC: E05F3/10
Filed: 1961-09-29
Abstract: 936,320. Door closers. REPUBLIC INDUSTRIES Inc. Sept. 29, 1961 [Oct. 18, 1960], No. 35162/61. Class 65 (1). [Also in Group XXXII] A door closer comprises a housing 42, 44, a door spindle 26 journalled in the housing and carrying a door-closing cam 74, at least one cam-following roller 92 journalled in a mounting means 102, 142 connected to one end of a pair of spaced guide rods 108 supported at their opposite ends in a crosshead 114 for linear sliding movement towards and away from the spindle, springs 112 biasing the mounting means in the door-closing direction, checking means controlling the door-closing movement of the spindle, and a pair of spaced guide rollers 130 journalled in the mounting means about axes parallel to the spindle axis, track elements 132 being positioned outwardly of and in engagement with the guide rollers. The closer is designed to be housed in the header tube of a door frame. The door is held in each of its fully-open positions by the engagement of one of the guide rollers 92 with a corresponding depression 100 in the cam 74, and in the event of the door being swung violently beyond the fully-open position the ends of the guide rods 108 abut the ends of a stiff leaf spring 162 secured to the end wall of the housing against a backing plate 164. The deflection of this spring also expels hydraulic fluid, with which the housing is filled, from between the spring and the backing plate and thereby increases the cushioning effect. The closing torque may be varied in the range 15-44 foot-pounds by suitable choice of the springs 112, three sets of which are supplied, and by adjusting the crosshead 114 by means of a screw 146 the end 148 of which is accessible from outside the housing. The hydraulic checking device comprises a cylinder 212 closed at one end by a cylinder head 224 and containing a spring- loaded piston 214 engaging the end 182 of a laminated push-rod slidably mounted in the housing and carrying at its other end a roller 170 which follows a checking cam 78. This cam is rotatably mounted on the spindle 26 and has a slot 84 engaged by an upstanding pin 82 on the closing cam 74, the slot being a little wider than the pin so that the checking cam is allowed about five degrees free rotation relative to the closing cam to ensure that, in the closed position of the door, the roller 170 is located to one side or the other of the nose 172 of the cam. The piston 214 is hollow (see Fig. 4) and contains a tubular guide member 228 which has a flange 230 engaged by one end of the spring 232 which loads the piston and houses a nylon pin 236 which slides under the control of a light spring 238. When the door is opened the piston and push-rod move towards the left under the action of the spring 232, and hydraulic fluid enters the cylinder through a non-return ball valve 258 (Fig. 3), and passage 254 in the cylinder head. During the major portion of the closing movement fluid leaves the cylinder through a passage 244 and control valve 248, but about fifteen degrees from the closed position the pointed end of the pin 236 closes the passage 244 so that for the remainder of the closing movement fluid can only flow through the passage 254 into a transverse passage 264 (Fig. 13), and through a control valve 266 which regulates the slow final closing speed. The cylinder head 224 is rigidly secured to the housing 42, 44, whilst the cylinder 212 is resiliently mounted, one end being held by an 0-ring seal 226 fitted in a groove in the cylinder head and the other being clamped between suitably shaped formations (Fig. 11, not shown), on the housing parts, a corrugated split ring (or wave spring) being fitted in a groove 218 in the cylinder. An opening closed by a threaded plug 290 (Fig. 3), is provided in the housing for filling the closer with hydraulic fluid, a vent opening closed by a plug 206 also being formed for the escape of air during the filling operation. A pressurerelease valve 268 loaded by a leaf spring 270 is located in the cylinder head.