A self-locking mechanism for a gearing arrangement, a gearing arrangement, an actuator, and a lifting platform, which relate to the technical field of lifting tables. The self-locking mechanism includes a casing, a self-locking gear, and a brake member, the self-locking gear meshing with the gearing arrangement, the brake member being connected between the casing and the self-locking gear; in a case where the gearing arrangement pushes the self-locking gear forwardly, the brake member releases the self-locking gear, and in a case where the gearing arrangement pushes the self-locking gear reversely, the brake member brakes the self-locking gear.

A reduction gearbox for solar photovoltaic tracking is provided. A sum of an included angle between an outer end surface of a first limiting protrusion and an outer end surface of a second limiting protrusion and a central angle of a limiting stopper is less than or equal to 170, that is, an angle at which a gear rotates from a hard limiting position of the first limiting protrusion and the limiting stopper to a hard limiting position of the second limiting protrusion and the limiting stopper is greater than or equal to 190. A difference between a central angle of a gear ring of the gear and a central angle of a worm is greater than or equal to 180. A photovoltaic panel may be rotated to be perpendicular to the ground, so that snow accumulated on a photovoltaic panel surface can be cleared to the utmost extent.

A switchable locking device has a switchable lock and an output shaft configured to receive the switchable lock and to be selectively connected to and disconnected from a rotational shaft via the switchable lock. When received by the output shaft, the switchable lock is configured to be selectively switched between an ON state and an OFF state. In the ON state of the switchable lock, the output shaft is connected to the rotational shaft for undergoing rotation therewith. In the OFF state of the switchable lock, the output shaft is disconnected from the rotational shaft and does not undergo rotation therewith.

A reduction gearbox for solar photovoltaic tracking includes a housing, an end cover, a gear, and a worm. A first limiting stopper is disposed on the top of the housing. A first limiting protrusion and a second limiting protrusion are disposed on a side of a gear ring of the gear, and the first limiting stopper, the first limiting protrusion and the second limiting protrusion define a hard limiting structure. The sum of an included angle between outer end surfaces of the first and second limiting protrusions and a central angle of the first limiting stopper is less than or equal to 170. The difference between a central angle of the gear ring of the gear and a central angle of the worm is greater than or equal to 180.

A ladder is disclosed which has a lockable pivot arrangement. The lockable pivot arrangement is located and connected between two elongate ladder sections. Inside each pair of end housings there are at least two receptacles. A pivot mechanism connects between the end housings and the end housings rotate in unison and also allow the pair of end housings to rotate relative to the housing. A lock mechanism within the housing has at least two lock members each with an actuator and each actuator having a free end. There is an elastomeric bias element acting to bias the two lock members and respective free ends and actuators away from each other, and the two actuators when biased apart are positioned so as to allow for one-handed actuation against the bias to unlock the rotation of the housing.