Abstract: A method and apparatus for monitoring an elevator drive brake wherein the method includes the steps of detecting a spring force (Fs-closed) when the brake is closed, detecting a spring force (Fs-open) when the brake is open, determining the difference between the two detected spring forces (?Fs), and comparing the difference between the two detected spring forces with at least one preset permissible force differential (?Fsmin; ?Fsmax) to determine whether the brake is defective. The apparatus includes a force sensor for each brake spring to be monitored, and an electronic monitor that stores at least one preset permissible force differential (?Fsmin; ?Fsmax) and, during operation, compares the at least one preset permissible force differential with an actual force difference (?Fs) between an open spring force (Fs-open) and a closed spring force (Fs-closed) as detected by the force sensor.

Abstract: With this safety disc brake all regulatory safety requirements can be fulfilled with a constructional expenditure approximately like that expended for a simple construction of brake. Fulfillment of the essential safety requirements is attained by providing two partial systems which mechanically operate completely independent of one another and comprise two identical brake levers each provided with a respective separate compression spring braced at a common central impact member fixedly connected with a machine part. As a further feature for fulfilling the safety requirements both of the partial systems are devoid of any mutual mechanical penetrations and overlapping. Opening or release of the brake is accomplished electromagnetically with a pot magnet fixedly secured to one brake lever and an armature plate likewise fixedly secured to the other brake lever.

Abstract: A gearless drive machine for elevators has a machine frame on which are mounted a counter roller carrier, a bearing block and an end plate block. The elevator cable strand spacing can be adjusted by a counter roller coupled to the counter roller carrier, whereby both a left-hand and right-hand overhang of the counter roller is possible with the same construction of the machine frame. A main shaft is supported at two places at a drive output end by a moveable bearing mounted in the bearing block and a fixed bearing mounted in the end plate block. A drive pulley having brake disc is located between the bearings and is coupled to the main shaft by a first detachable coupling. The support of the drive pulley on both sides thereof allows great radial loads with only small deformations of the main shaft. A hoist motor supplied with alternating voltage has a stator with windings and a rotor with a rotor hub slidable onto the main shaft.

Abstract: A shoe or friction brake having the brake levers thereof connected both at the pivotably mounted end and also at the end driven by a brake spring mutually independently of one another at the brake housing. The pivotably mounted end is connected with the brake housing by elements which have a resilient or spring action perpendicular to the direction of action of the brake spring. These resilient elements are in the form of plate springs and/or a leaf or blade spring. The bearing means for each brake lever is arranged between the plate springs. Each brake lever has operatively associated therewith a choke or reactance coil, and the choke yoke or the like is arranged at the bearing means and the choke core at the brake housing. With the brake levers located in their braking position the latter, when subjected to load, are movable perpendicular to the direction of action of the brake springs, so that the air gaps of the choke coils can be reduced or increased in size, as the case may be.