Patent GB-925095-A (GB)
Title: Improvements in or relating to door closing and checking devices
Inventor: VOESTER WALTER
IPC: E05F3/10
Filed: 1960-09-02
Abstract: 925,095. Door closers. VEREINIGTE BAUBESCHLAG-FABRIKEN GRETSCH & CO. G.m.b.H. Sept. 2, 1960, No. 30287/60. Class 65 (1). A door closing and checking device comprises a closer spindle 4 rotatable in both directions and extending out of a housing 1, a helical closer spring 21, the end of which nearer to the spindle is operatively connected by a guide rod 27 with a single-armed rocking lever 26 mounted in the housing and provided with a roller 28 engaging a closer cam 5 mounted on the spindle, and a piston and cylinder damping arrangement accommodated within the helical closer spring, the piston 16 being urged by a spring 19 towards the spindle and motion being transmitted between the spindle and the piston through a damping cam 6 on the spindle, the two cams being differently shaped. Preferably, the housing 1 is arranged in an installation box 3, and may be angularly adjusted about the spindle, and clamped in the adjusted position by a screw 35. In a first embodiment (Figs. 2, 3), the piston-rod 17 of the damping piston carries a roller 18 in engagement with a cylindrical edge portion of a rocking lever 30 pivoted on the same pin 25 as the rocking lever 26 and carrying a roller 31 resting on the cam disc 6. The closer spring 21 is located between an adjusting ring 22 screwed on to the damping cylinder and a spring plate 23 slidable on the cylinder and pivotally connected to the guide rod 27. The cam disc 5 has a recess 29 engaged by the roller 28 in the door-closed position and is so arranged that the torque tending to close the door is very high when the angle of opening is small, drops away rapidly to remain fairly constant in the medium opening range, and decreases to zero when the angle of opening reaches 180 degrees. During the first 90 degrees of opening movement the roller 31 approaches the closer spindle 4 and damping fluid enters the cylinder 7 through a non-return valve 10, but on further opening of the door to 120 degrees the roller rides up on to the circular part of the cam 6 and the door movement is damped, fluid leaving the cylinder through a regulating valve 11. If desired, the cam 6 can be so shaped that the damping is effective up to an angle of opening of 180 degrees. In a modification (Fig. 7), two rocking levers 26 are provided, one above and one below the rocking lever 30, each pivoted to a guide rod 27 slidably engaging the spring plate 23 and connected to the housing 1 by a pivoted link 43. Alternatively; instead of engaging the spring plate 23 directly, the guide rods 27 may each carry a roller 46, (Fig. 9) resting on a slide 47 guided on the damping cylinder and pivoted at each side of the cylinder tb a rocker 48 pivotally supported on a stop 50 at the bottom of the housing 1 and formed with an arcuate edge resting on the spring plate. Various arrangements are described for preventing the damping mechanism from reaching its dead-centre position with respect to the closer spindle when the door is closed. In Fig. 13, the cam 6 is rotatably mounted on the spindle and is connected thereto by a crank-pin 4c carried by the spindle and engaging a slot 6a in the cam. Alternatively or in addition the roller 31 may be slidably mounted in a slot 30a in the rocking lever 30. The mechanism is shown at the completion of a clockwise closing movement; if the door begins to open in a clockwise direction the roller 31 and the cam 6 snap into a similar abutting position on the other side of the deadcentre. In another arrangement (Figs. 15-16, not shown), the cam 6 is fixed on the spindle and the piston-rod 17 carries the roller 31 and is pivotally connected to the piston, the rocking lever 30 being dispensed with and the lateral movement of the piston-rod being limited by a pair of fixed guide rollers. In the door closer shown in Fig. 17 (which is a modification of that -shown in Fig. 7) the end of the piston-rod 17 carries a hinge piece 52 pivoted by a pin 53 to a connecting rod 54 having at its other end a pin 57 working in transversely extending cam slots 58 in the two parts of the cam 6. Just before the door reaches its fully closed position the pin 53 abuts the roller 46 carried by the guide rod 27 so that the force of the spring 21 is shortcircuited from the spindle 4 to the damping arrangement and sudden closing is prevented.