A knob mechanism according to the disclosure may include a knob body and a lock mechanism associated with the knob body. The lock mechanism may include a locking member that is movable between an extended position and a retracted position, a pivot member that is pivotable with respect to the knob body to move the locking member, and a button that is operable to pivot the pivot member to move the locking member from the extended position toward the retracted position.

A crank assembly with an adjustable handle assembly that includes a handle mounted on bearings and on an axle such as a self-locking, quick-release pin. The pin allows the handle assembly to be removably positioned in any of a number of holes in the crank body allowing choice of high leverage or high speed during crank operation. While designed with hand-cranked trailer jacks in mind, the crank assembly can be used in various applications requiring hand cranking by suitable choice of crank interface and dimensions. An adapter at the crank interface may be used alone with a power drive tool or by hand with the crank assembly.

A hand crank structure of a trailer jack is provided, including a shaft, a rotating shaft, a handle assembly, a spring, and a locating ring. A circumferential locating hole is disposed on an end of the handle assembly, and the handle assembly is sleeved on the rotating shaft by using the circumferential locating hole and is able to move axially on the rotating shaft. A circumferential locating member is disposed in a moving range of the handle assembly corresponding to the rotating shaft, after the handle assembly slides outward, the circumferential locating hole cooperates with the circumferential locating member to rotate synchronously, and after the handle assembly slides inward, the circumferential locating hole is separated from the circumferential locating member.

A crank arrangement (100) for operating a winch having an elongate crank arm (10), a hollow driving head (29) having an external engagement profile, a handle part (40) and a locking plate (25) arranged at an outer end of an actuator element rotatably taken up within the hollow driving head (29). Hinged lever arms (11A, 11B) extend in parallel on external opposite side walls of the crank arm (10) having protruding pins (18A, 18B) for, when at least one hinged lever arm (11A, 11B) is gripped, actuating upon the actuator element rotationally connected to the locking plate (25) such that the locking plate (25) will perform a rotational movement to assume a first position in which the locking plate (25) is aligned with the engagement profile of the driving head (29). When at least one the hinged lever arms (11A, 11B) is released, the locking plate (25) will be rotated to assume a second, locking, position in which it is misaligned with the engagement profile (30) of the driving head (29) limiting the rotational movement of the actuator element being provided. The locking plate (25) can be rotated to assume the first position via a one-hand grip.