Automatic load brake

Abstract

The disclosure is of an improvement of automatic load brakes, of the type generally and generically known as a Weston disk brake, as used, for example, in braking a hoisting drum adapted for reeling in and reeling out a cable suspending a load. The frictional brake disks and plates, while lowering the load, experience a feed-back torque from the load. Means are provided for feeding only a proportional part of the total energy so fed back to only a fraction of the brake plates, whereby to instantly break these loose for relative rotation in response to lowering inputs. By this feature, response is instantaneous, and no further provisions are required to break away or accelerate the plates. Improvements are also disclosed by which, when feed-back is controlling the application of the brake, the usual oscillatory application of the brake, i.e., chatter, is stabilized and virtually eliminated. Another feature is continuous oil cooling of the brake disks and rings during the duty cycle of the brake (reeling out) and also during the off-duty cycle of the brake (reeling in), thus lowering the average temperature of the cooling oil. This is accomplished by an integral gear pump which pumps cooling oil continuously, and automatically reverses position to accomplish this as the direction of cable travel reverses.