Hoisting and lowering device
A device, system and method are used for hoisting and lowering a load. The device has a front plate that may be displaced to reveal a sheave. The device also has a friction accessory. The friction accessory is arranged to create friction between a rope and the device when a load is suspended from the device using the rope and where the device is secured to a support structure. The system may be prepared by an operator, having ascended to an elevated location, and further allows the operator to lower the load from the elevated location prior to descending.
1. A device for controlling the hoisting and/or lowering of loads through the use of friction applied to a cable, the device comprising:
a main body having a rear wall, a cylindrical post extending forwardly from the rear wall, the main body having a boss that also extends forward from the rear wall, the boss having a front surface, a height of the boss being defined from the rear wall of the main body to the front surface of the boss;
a sheave supported on the cylindrical post for rotation relative to the main body and being positioned adjacent to the boss of the main body, the sheave including a front face and a rear face, the rear face of the sheave being adjacent to the rear wall of the main body, a thickness of the sheave being defined between the front face and the rear face of the sheave, the thickness of the sheave being less than the height of the boss, the sheave also including an outer circumferential groove, the outer circumferential groove sized and configured to accommodate a portion of an outer surface of a cable, a bolt securing the sheave to the main body, the bolt being threadedly engaged with the cylindrical post of the main body;
a front plate overlaying the front face of the sheave and selectively overlaying the front surface of the boss of the main body, the front plate comprising a first opening, the bolt extending through the first opening, the bolt defining a rotational axis for the front plate, the front plate including a second opening, the second opening being defined as a slot, the slot selectively engageable by a releasable clasp, the releasable clasp being secured to the boss and being axially movable relative to the boss, a front surface of the releasable clasp defining a push-button that causes axial translation of the releasable clasp, the releasable clasp selectively restraining the front plate against rotation relative to the main body; and
a friction accessory extending away from the sheave, the friction accessory being offset from the thickness of the sheave such that, when viewed from the side, a plane defined by the rear face of the sheave does not intersect the friction accessory, the friction accessory being unitary and monolithic with the main body, the friction accessory including a gate that is pivotally secured to the main body, and the friction accessory and the gate defining an enclosed space that is configured to capture an entire diameter of at least a portion of the cable when the cable is wrapped at least one time around at least a portion of the friction accessory.
2. The device of claim 1 , wherein the friction accessory extends tangentially away from the sheave.
3. The device of claim 2 , wherein the friction accessory comprises a first portion that extends tangentially away from an outer circumference of the sheave, the first portion terminating at a hook-shaped end that bends back towards the sheave.
4. The device of claim 3 , wherein the gate extends tangentially away from the sheave.
5. The device of claim 4 , wherein the gate comprises a recess that receives a distal end of the hook-shaped end of the first portion of the friction accessory.
6. The device of claim 3 , wherein a portion of the front plate is covered by a portion of the boss when the front plate is restrained against movement by the releasable clasp.
7. The device of claim 6 , wherein the releasable clasp comprises a circumferential recess that, when axially aligned with the front plate, releases the front plate from engagement with the releasable clasp.