Abstract: Torque is transmitted between the driving and driven members of the clutch by a helical spring and a friction shoe. When an electromagnet is excited, pilot torque is applied to the spring to cause the spring to clamp downwardly around the shoe and cause the shoe to contract radially around the driving member and transmit torque to the driven member. The driving member, the driven member, the spring and the friction shoe are arranged in such a manner that the spring effects soft engagement of the clutch while amplifying the pilot torque sufficiently to enable a relatively small and light weight clutch to produce ample output torque.

Abstract: The control collar of a helical spring clutch is defined in part by a series of rings having radially projecting stop lugs which coact with an interposer. The rings may be adjusted angularly relative to one another to cause the lugs to effect successive disengagements of the clutch as the output member of the clutch is rotated through a selectively adjustable number of steps of selectively adjustable angular length.

Abstract: An electromagnetic friction brake whose components are held in assembled relationship by pins which are received with a press fit within holes in an electromagnet and an end plate and which are received with a loose fit within holes in an armature. By virtue of the pins, an assembly gage may be used to automatically establish an air gap of desired width between the armature and the electromagnet when the brake is assembled.

Abstract: The armature of an electromagnetic clutch is connected to an axially fixed elastomeric ring by leaf springs which urge the armature away from the electromagnet. Rivets connect the springs to the armature and are formed with pin-like extensions which are telescoped snugly but slidably into holes in the ring. When the magnet is initially excited, the ring frictionally retards movement of the pin-like extensions to cause the armature to softly and quietly engage the magnet rather than slapping sharply against the magnet.

Abstract: An electromagnet in which an oblong block of friction material captivates a coil on an oblong plate which is stamped from sheet metal. One pole of the magnet is formed by a stud which is secured to the plate while the other pole or poles either are formed by flanges bent from the plate or by an additional stud or studs secured to the plate.

Abstract: The magnet core of an electromagnetic clutch is substantially J-shaped in radial cross-section and includes an outer pole ring which is spaced radially outwardly from and which only partially surrounds the outer pole ring of the rotor of the clutch. The controlled transfer of flux between the core and the rotor occurs both in a radial direction and in an axial direction.

Abstract: An electromagnetic friction brake whose components are held in assembled relationship by pins which are received with a press fit within holes in an electromagnet and an end plate and which are received with a loose fit within holes in an armature. By virtue of the pins, an assembly gage may be used to automatically establish an air gap of desired width between the armature and the electromagnet when the brake is assembled.

Abstract: Apparatus and controls for indicating the position of a stepping motor rotor as it successively steps and without the need for physically driven encoders or pulse generators, characterized by arrangements for sensing the current, or the rate of change of current, flowing in the motor windings. The intelligence indicating when the rotor reaches successive positions is applied advantageously to a utilization device such as a counter to signal the position of a driven load, and is used to control sequenced energization of the motor windings to create the advantages of a closed loop system but without a driven feedback device.

Abstract: A control system of the type which provides "breakaway" safety action to energize the electrically actuatable coils of brakes in a trailer pulled by a towing vehicle, the coils being energized under a breakaway condition from an auxiliary battery carried in the trailer. The system includes a voltage threshold indicator which is connected across the auxiliary battery and the coils and which enables the driver to test the auxiliary battery and clearly determine if the battery has sufficient storage capacity to keep the coils adequately energized while load current is being drawn from the battery and supplied to the actual coils themselves -- such system being characterized by the provision of a current threshold sensor which prevents the indicator from providing a "safe" signal if the excitation circuit to the coils has been interrupted or if one or more of the coils has become disconnected from the circuit.

Abstract: A control system of the type which provides "breakaway" safety action to energize the electrically actuatable coils of brakes in a trailer pulled by a towing vehicle, the coils being energized under a breakaway condition from an auxiliary battery carried in the trailer. The present system is characterized by a voltage threshold indicator which is connected across the auxiliary battery and the coils and which enables the driver to test the auxiliary battery and clearly determine if the battery has sufficient storage capacity to keep the coils adequately energized while load current is being drawn from the battery and supplied to the actual coils themselves. The indicator preferably is incorporated in a pull-apart breakaway switch unit which automatically connects the brake coils with the auxiliary battery in the event of a breakaway.

Abstract: The electromagnet of an electrically controlled brake is prevented from rotating on its mounting pin by a bracket which also captivates the magnet against axial removal from the pin while leaving the magnet free to pivot and float axially on the pin. The bracket is made of a strip of resiliently yieldable material and includes a leg paralleling the pin and secured at one end of the magnet. The other end portion of the leg extends through a hole in the brake operating arm and is integral with a tang which engages the arm to captivate the magnet against axial removal from the pin.

Abstract: An electrically controlled brake assembly for a vehicle wheel of the type in which an operating arm is mounted between its ends to turn about a pivot on a backing plate and carries at least one electromagnet on one of its ends. Two downwardly projecting tongues are formed on the lower end of the pivoted operating arm of the brake assembly and ride in a channel defined by a guide which is attached to the backing plate of the assembly, the tongues and the guide coacting to prevent the operating arm from cocking on its pivot during braking.

Abstract: Permanent magnets are interposed within the circumferential spaces between the circumferentially spaced pole pieces of the stator of a variable reluctance step motor. The magnets are magnetized in a circumferential direction and serve to increase the dynamic and holding torque characteristics of the motor while providing the motor with detenting torque and while dampening overshoot and oscillation of the rotor of the motor as the rotor arrives at and settles into its detent positions.

Abstract: A clutch-brake assembly includes input and output hubs, respectively, fixed and journaled on a rotatable shaft. A coil spring secured for movement with the output hub normally is wound into driving engagement between the input and the output hubs. A sleeve telescoped over the spring is fixed to the output hub and a low inertia braking member loosely mounted on the free end of the sleeve is held against substantial movement in both radial and axial directions with respect to the sleeve. In one form of the invention, a tang on the spring projects into a slot in the braking member and thus connects the member with the spring so the member normally rotates with the shaft but, when a braking torque is applied to the member, the spring is unwound from between the two hubs to disengage from them and subsequently to transmit the braking torque to the output hub to retard rotation thereof. In another form of the invention, a tang is integrally formed with the braking member to engage the input end of the spring.

Abstract: The unit includes an electromagnet which may be energized to effect shifting of an armature from a clutching position in which the armature couples driving and driven elements to a braking position in which the armature engages a braking member to produce braking of the driven element. The braking member normally is locked against rotation so as to apply a braking torque to the armature and the driven element but may be selectively unlocked and permitted to rotate so as to enable the armature and the driven element to free-wheel.

Abstract: A disc brake retards the motion of the normally stationary output member of a helical spring clutch and serves to brake the rotary input member of the clutch to a gradual stop when a coiled helical spring is contracted to couple the output member to the input member.