An example system includes a disk that is rotatable and has a plurality of ferromagnetic elements disposed in a radial array on a surface of the disk; and at least one electro-permanent magnet (EPM) mounted adjacent to the disk such that a gap separates the disk from the EPM. Applying an electric pulse to the at least one EPM changes a magnetic state thereof, thereby generating an external magnetic field that traverses the gap between the disk and the EPM and interacts with a ferromagnetic element of the plurality of ferromagnetic elements, and causing a rotational speed of the disk to change as the disk rotates.

A hub motor is provided with a simplified structure to make an automobile more cost effective. The hub motor includes a center shaft, a brake disc fixedly connected with the center shaft, a coil support sleeved on the center shaft, and a motor controller. The coil support advantageously includes first and second coil supports that include first and second vents, respectively.

This device is magnetic brake assist, traction control and forward assist. It uses magnets inserted in the vehicles rims and in a stationary hub bolted behind the wheels hub and brake disk; to either slow the rotation of the tire down or speed the rotation up for braking and or for forward assist.

A rotational resistance apparatus includes a rotational shaft member including a first shaft portion, a second shaft portion, and a third shaft portion disposed between the first and second shaft portions and having a diameter larger than that of each of the first and second shaft portions, and the rotational shaft member being made of a magnetic material, a housing member configured to hold the rotational shaft member and made of a magnetic material, a first coil disposed between an outer circumferential surface of the first shaft portion and an inner circumferential surface of the housing member, a second coil disposed between an outer circumferential surface of the second shaft portion and the inner circumferential surface of the housing member, and a magnetic viscose fluid disposed between an outer circumferential surface of the third shaft portion and the inner circumferential surface of the housing member.

Systems and methods for an improved walker are provided. The inventive walker allows for greater control over the speed of the walker. More specifically, wheels having specific characteristics may be used to control the speed of rotation of the wheels. For instance, the wheel may include an inner wheel assembly including a coil or coils, and an outer wheel assembly including a magnet or magnets. A magnetic field may be created using current through the coils, which in turn limits the speed with which the outer wheel assembly can be rotated relative to the inner wheel assembly. The present invention also includes a control system used to control the speed and other characteristics of the walker. The present invention may also collect associated data and display of the same which can help determine future activities associated with the walker.

Electric power tools with safety brakes that include impulse solenoids and methods of operating the electric power tools. The electric power tools include an implement holder configured to hold an implement, which is configured to perform an operation on a workpiece. The electric power tools also include a motor, which is configured to actuate the implement holder to move the implement, and a safety brake. The safety brake includes a brake assembly configured to be transitioned between a disengaged configuration, in which the brake assembly permits motion of the implement, and an engaged configuration, in which the brake assembly resists motion of the implement. The safety brake also includes an actuator assembly configured to selectively provide a motive force to transition the brake assembly from the disengaged configuration to the engaged configuration. The actuator assembly includes an impulse solenoid and solenoid drive circuitry.

A liquid damper system for restraining vibrations generated in a rotating body includes: a liquid damper which is coaxially rotatable with the rotating body and includes a collision member, the collision member being provided in a casing in which liquid is enclosed and the liquid colliding with the collision member when moving in the circumferential direction; and a relative rotation unit configured to cause the liquid damper to rotate relative to the rotating body. Vibrations of a rotating body are effectively suppressed when a rotating body steadily rotates at a main resonance frequency, in the liquid damper system.

Described herein is a system, method of use and Self Retracting Lifeline (SRL) apparatus using a system that governs a dynamic response between members causing a halt in relative motion between the members. Magnetic interactions, eddy current drag forces and centrifugal and/or inertial forces may provide various mechanisms of governing movement.

A detection method for detecting the blocked or unlocked state of a parking brake member including a bistable linear electromagnet (1) connected both to a power supply component (14) arranged to generate a control voltage (U.sub.c) and also to a current sensor (15) arranged to measure the control current (I.sub.c), the detection method comprising the steps of: controlling the power supply component (14) to generate a test voltage (U.sub.test) across the terminals of the coil and thus generate a test current (I.sub.test) flowing in the coil, the test voltage having an amplitude less than a predetermined voltage threshold so that a test magnetic field generated by the test current does not move the shuttle; acquiring measurements of the test current as produced by the current sensor (15); and analyzing the measurements of the test current and detecting the blocked or unlocked state of the parking brake member on the basis of this analysis.

By means of the system described, the use of eddy current generators on vehicles, especially bicycles, can be simplified by easier integration into standardized components such as brake pads, making them more suitable for everyday use. The problem of overcoming the magnetic holding forces at low speeds is essential for cyclists, as these would otherwise rule out the use of such systems in everyday traffic due to the lack of power generation when starting off at low speed. The integration into brake pads provides a significant advantage, as a new functionality is achieved without the need for additional components. The claimed additional functions for signalling contribute to increased traffic safety, especially for two-wheel traffic.