GB466407A - Improvements in and relating to combined service and safety brakes for shaft elevators - Google Patents

Abstract

466,407. Fluid - pressure brakes. SHEVLIN, J. T. (Siemens-Schuckertwerke Akt.-Ges.) Jan. 8, 1937, No. 660. [Class 103 (i)] In a brake system for shaft elevators of the kind in which the normal or service brake is actuated by the admission of compressed air or steam to an operating cylinder and is combined with a safety brake operated by means of a weight, the service brake cylinder 5 and piston 6 are movably interposed in the link system between the safety weight 13 and the brake blocks 2 so that, when the safety braking means become operative, both the cylinder 5 and the piston 6 are displaced. In the arrangement shown in Fig. 1, the piston 6 is operated to apply the brakes by admitting compressed air to the cylinder 5 from a container 18 via a valve 19 and flexible piping 31, while the weight 13 is normally maintained in a raised position by admitting pressure to a cylinder 14 through a pipe 20 and control valve 21. The rods 8, 30 which actuate the valves 19, 21 are connected to a common differential lever which permits the valve 19 alone to be actuated, or in the case of emergency, both valves 19, 21. In the latter case, the cylinder 5 and piston, being mounted on the end of a pivoted lever 10 of the safety brake mechanism, move upwardly to apply the brakes to the drum 1. In a modification, Fig. 2 (not shown), the service cylinder 5 is mounted upon the piston of the safety brake cylinder, this piston in turn being carried upon the end of the lever 10. In another construction, Fig. 3, the service brake cylinder 52 is formed as part of the piston 43 of the safety brake, which is controlled by a weight 44. The pistons 43, 53 are additionally controlled by the admission of fluid pressure through ducts 49, 56 under the control of service and safety brake levers 60, 75 coacting with a differential lever 69. A safety release magnet 64 is also incorporated. The pressure in the annular space 50 surrounding the cylinder 52 may be maintained by the closing of an adjustable throttle valve 72, the position of which may depend upon the pressure in the fluid supply pipe 62.