Brakes – Operators – Speed-responsive
Patent
1997-03-17
1999-05-18
Schwartz, Chris
Brakes
Operators
Speed-responsive
188184, 188 8274, 188 8277, 187305, 187373, B60T8/72
Patent
active
059042290
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a brake assembly which is used as an automatically activated emergency brake for among other things lifting platforms and elevators.
2. Description of the Prior Art
Automatically activated emergency brakes are previously known, for instance, from publications SE-302675 and 308785 illustrating the brake constructions, which, in case of emergency, brake and stop motion because of a speed higher than a set speed. The disadvantage of these known constructions is the very complicated disassembly of the locking system. In lifting platforms and elevators the brake is always locked. After an emergency stop the platform or elevator may be very high up. Disassembly of the brake locking system is accomplished by opening the brake gear, which means getting into an-uncontrollable state, where the elevator or lifting platform is not locked in position by any other means. If the fault is in the driving motor or its axles, the driving motor has no retaining capacity and so an emergency situation arises when the brake is being disassembled. In any case, the disassembly of the locking of these designs is a time-consuming and risky procedure as well as a hazardous job. Even checking the working order of these emergency brakes requires a braking test, after which the brake locking must also be disassembled by opening it with a tool.
By means of the brake assembly according to this invention these disadvantages are avoided.
SUMMARY OF THE INVENTION
A brake assembly for braking or stopping uncontrolled motion, by means of which rotational motion and also linear motion, of lifting platforms or similar vertically moving lifting housings is braked, wherein the linear motion is first turned into rotational motion by power transmission means. The brake assembly includes a housing fixed in a hoist gear so that the rotational motion, which is to be braked, is transmitted from the hoist gear to an axle of the brake assembly. A coupling is fitted on said axle for transmitting rotational motion to a braking gear, said coupling being comprised of a locking device, which is released by an adjusted rate of centrifugal force provided by rotational motion, by means of which locking device the coupling is locked to transmit rotational motion between the axle and the braking gear. The locking device is, when locked, fitted to transmit rotational motion in the opposite direction with respect to the direction of locking, in order to open the locking device by turning the axle in the opposite direction. The coupling includes a retaining shoulder to prevent the locking, device from returning immediately into an unlocked position when the brake is being released by counterwise rotation of the axle. The braking gear locks the rotational motion of the axle with regard to the assembly housing. The improvement comprising that the rotational motion over the coupling is, in an initial stage of braking, arranged to tighten the braking gear by an axial spring tensioning motion produced by a mutually stepped pair of counter surfaces formed in a sleeve attached to the coupling and a support flange is fitted with the sleeve such that rotation of the sleeve transmits a sudden axial motion to support flange to tighten the spring. In an initial stage of releasing the brake the rotational motion over the coupling is arranged to loosen the braking gear by an axial spring tension reducing motion produced by the mutually stepped pair of counter surfaces of the support flange and sleeve.
The most important advantage of this invention is that the brake locking can be opened simply by lifting the platform or elevator, i. e. in turning the brake assembly axle in the opposite direction. If the lifting motor and transmission of the lifting platform or similar equipment is in good working order, the brake can be opened safely and successfully without even touching the brake gear. Thus brake testing is an easy job. The brake opens automatically during the reverse rotation of the axle and is co
REFERENCES:
patent: 4257494 (1981-03-01), Frankel
patent: 4856623 (1989-08-01), Ronig, Jr.
patent: 5141085 (1992-08-01), McCormick
patent: 5222578 (1993-06-01), Thorp
patent: 5287950 (1994-02-01), Feathers et al.
Oy Scaninter Nokia Ltd.
Schwartz Chris
LandOfFree
Brake assembly does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Brake assembly, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brake assembly will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1753991