An electric winch device includes a required braking force estimation section which estimates a required braking force required to stop a free-falling object at a position at an allowable stopping height; a braking force determination section which determines, out of an operational braking force, each of a first braking force to be borne by a braking device and a second braking force to be borne by a braking force which is generated in an electric motor due to consumption of regenerative power; and a control section which causes the braking device to apply the first braking force to a winch drum. The braking force determination section determines the first braking force to be a braking force equal to or greater than the required braking force when, at a time of stopping of the free-falling object, the operational braking force is equal to or greater than the required braking force.

Described herein are methods and systems for picking up, transporting, and lowering a payload coupled to a tether of a winch system arranged on an unmanned aerial vehicle (UAV). For example, the winch system may include a motor for winding and unwinding the tether from a spool, and the UAV's control system may operate the motor to lower the tether toward the ground so a payload may be attached to the tether. The control system may monitor an electric current supplied to the motor to determine whether the payload has been attached to the tether. In another example, when lowering a payload, the control system may monitor the motor current to determine that the payload has reached the ground and responsively operate the motor to detach the payload from the tether. The control system may then monitor the motor current to determine whether the payload has detached from the tether.

A system includes two or more lifting devices attached to a structure each lifting device having a drum rotated by a motor to draw in or let out a line from the drum. The drum includes a groove formed in an outer surface thereof to accommodate the line. In certain embodiments, each of the lifting devices are quickly and easily detachable from the structure by way of a flange and mounting bracket. The flange and mounting bracket have holes which are coaxially aligned. A pin or other fastener is used to join the flange and mounting bracket together. Two or more lifting devices may be connected to and moved along a mounting bracket.

Described herein are methods and systems for picking up, transporting, and lowering a payload coupled to a tether of a winch system arranged on an unmanned aerial vehicle (UAV). For example, the winch system may include a motor for winding and unwinding the tether from a spool, and the UAV's control system may operate the motor to lower the tether toward the ground so a payload may be attached to the tether. The control system may monitor an electric current supplied to the motor to determine whether the payload has been attached to the tether. In another example, when lowering a payload, the control system may monitor the motor current to determine that the payload has reached the ground and responsively operate the motor to detach the payload from the tether. The control system may then monitor the motor current to determine whether the payload has detached from the tether.

A method of powering an intermittent-duty cycle winch is disclosed. The method includes identifying a number of amp-hours required to power the winch through one duty cycle, identifying a minimum required rest period between two consecutive duty cycles, and assembling a power supply unit that powers the winch based, at least in part, on the duty cycle and the rest period. The duty cycle is mechanically or thermally limited. The power supply unit includes at least two components: a power storage unit and a charging unit that recharges the power storage unit during the rest periods. The power storage unit powers the winch through at least one duty cycle. The charging unit recharges the power storage unit during the rest period so that the power storage can power the winch through at least a second duty cycle that immediately follows the end of the minimum required rest period.

An improved firefighter SCBA harness is provided. The harness has a backplate for supporting an air cylinder. A waist belt extends from the backplate to secure the backplate to a waist of a firefighter wearing the SCBA harness. Shoulder straps extend from a top of the backplate connecting to the waist belt. A seat harness extends from a bottom of the backplate to a front of the waist belt for positioning through the legs of a firefighter. A bailout cable kits provides a spool on the waist belt for extending a cable from the harness to enable the firefighter to perform a bailout, used in a retrieval or as a fall restraint. A battery powered winch may also be integrated in the harness.

A variable frequency drive motor system includes a variable frequency drive motor and a controller coupled to the motor. The controller includes a rectifier, a direct current (DC) link bus, and an inverter. The controller is configured to determine that a brake has failed. In response to the determination that the brake has failed, the controller is configured to determine that power to the controller from a power supply has been interrupted. In response to the determination that power to the controller has been interrupted and a determination that a DC voltage across the DC link bus is below a first threshold value, the controller is configured to drive the motor at a faster speed.

An electrically driven winch device includes a winch drum, a plurality of axial-gap electric motors, and a drive shaft. The winch drum rotates around a drum axis in order to wind or unwind a work rope. The plurality of electric motors are electric motors configured to drive the winch drum to rotate, and are each provided with a stator, and rotors which rotate around a rotation axis and are disposed at an axial distance from the stator. The drive shaft is disposed coaxially with the drum axis and serially connects the rotors of the plurality of electric motors on the rotation axis.

A line tensioner is disclosed. A winch has a winch drum with at least one groove over which a line is passed. The winch has a line tensioner assembly with a stationary cam surface and a plurality of line tensioners rotating with the winch drum. Each has a line gripping portion and a cam follower. The line gripping portion is brought into and out of contact with the line as the cam follower rides along at least a portion of the cam surface.

Units for distributing three-phase power to a plurality of chain motors are provided, as are used to raise and suspend production elements such as lighting, sound, video, and scenery. Remote switching and phase reversal of such power are also provided. In the prior art, such switching has been performed by large, heavy contactors inserted between the single power input and its distribution to plural outputs for motors, making the unit difficult to handle and ship. Provided herein are power switching and phase reversal performed by a plurality of parallel such means, reducing the current requirements for each, and thereby the size, weight, and cost of the whole. In some embodiments, the single power input is replaced by a by a cable delivering a plurality of two-phase circuits to the unit which derives the three-phase circuits necessary for chain motors therefrom.