Certain embodiments of the present application relate to an unmanned aerial vehicle including a control system, at least one rotor operable to generate lift under control of the control system, a spool mounted for rotation in a winding direction and an unwinding direction opposite the winding direction, a motor operable to rotate the spool in at least the winding direction under control of the control system, and a brake mechanism including a brake actuator operable to transition the brake mechanism between a locked state and an unlocked state under control of the control system. The brake mechanism in the locked state prevents rotation of the spool in at least the unwinding direction. The brake mechanism in the unlocked state does not prevent rotation of the spool in the unwinding direction.

A brake device comprising: a brake receiver pivotally supported in a non-rotatable manner on the drive shaft and including a flange part and a boss part; a female screw member pivotally supported in a rotatable manner on the drive shaft and screwed to a male screw part; a ratchet wheel including ratchet teeth provided on an outer peripheral side and configured to restrict a rotation direction to one direction; a brake plate arranged between the ratchet wheel and at least one of the flange part and the female screw member; and at least one pawl member engaging, on a tip side, with a valley part located between adjacent ratchet teeth, and meshing with the ratchet tooth, wherein the ratchet teeth include tall teeth and short teeth lower in projection height from a rotation center of the ratchet wheel than the tall teeth.

A brake device comprising: a brake receiver pivotally supported in a non-rotatable manner on the drive shaft and including a flange part and a boss part; a female screw member pivotally supported in a rotatable manner on the drive shaft and screwed to a male screw part; a ratchet wheel including ratchet teeth provided on an outer peripheral side and configured to restrict a rotation direction to one direction; a brake plate arranged between the ratchet wheel and at least one of the flange part and the female screw member; and at least one pawl member engaging, on a tip side, with a valley part located between adjacent ratchet teeth, and meshing with the ratchet tooth, wherein the ratchet teeth include tall teeth and short teeth lower in projection height from a rotation center of the ratchet wheel than the tall teeth.

A winch has a cable reel, a winch body capturing the cable reel, and an indexing lock. Two separately actuated pawls provide a first level of fail-safe protection. A drive coupler enables rapid torque wrench cable tension adjustment. Locking pin holes on the cable reel and winch body are arranged so a locking member can pass through only one visible winch body locking pin hole, with the other visible holes at least partially blocked, independent of pawl position. The locking pin provides a second level fail safe. As the cable reel is rotated by the drive coupler, even by a small amount less than required for a single pawl ratchet tooth displacement, another visible winch body locking pin hole will align and open. As a result, very precise cable tension and reel position can be preserved by insertion of the locking pin into the only open locking pin hole.

A winch has a cable reel, a winch body capturing the cable reel, and an indexing lock. Two separately actuated pawls provide a first level of fail-safe protection. A drive coupler enables rapid torque wrench cable tension adjustment. Locking pin holes on the cable reel and winch body are arranged so a locking member can pass through only one visible winch body locking pin hole, with the other visible holes at least partially blocked, independent of pawl position. The locking pin provides a second level fail safe. As the cable reel is rotated by the drive coupler, even by a small amount less than required for a single pawl ratchet tooth displacement, another visible winch body locking pin hole will align and open. As a result, very precise cable tension and reel position can be preserved by insertion of the locking pin into the only open locking pin hole.

Certain embodiments of the present application relate to an unmanned aerial vehicle, comprising a chassis, a control system mounted to the chassis, at least one rotor operable to generate lift under control of the control system, a spool having a wound portion of a line wound thereon, the line including a free portion, an attachment device secured to the free portion of the line and configured to facilitate attachment of a parcel to the line, a motor operable to rotate the spool under control of the control system such that the control system is operable to raise the attachment device to a raised position and lower the attachment device from the raised position, and a spring positioned between the chassis and the attachment device such that the spring is engaged between the chassis and the attachment device when the attachment device is in the raised position.

Certain embodiments of the present application relate to an unmanned aerial vehicle, comprising a chassis, a control system mounted to the chassis, at least one rotor operable to generate lift under control of the control system, a spool having a wound portion of a line wound thereon, the line including a free portion, an attachment device secured to the free portion of the line and configured to facilitate attachment of a parcel to the line, a motor operable to rotate the spool under control of the control system such that the control system is operable to raise the attachment device to a raised position and lower the attachment device from the raised position, and a spring positioned between the chassis and the attachment device such that the spring is engaged between the chassis and the attachment device when the attachment device is in the raised position.