Provided is a travel operation device for a crawler aerial work vehicle equipped with an operation panel that can be operated with one hand and that provides stable operating conditions even when swayed from side to side. A travel operation device 10 comprises an operation panel 11 that is disposed on the deck 4 of a self-propelled crawler aerial work vehicle 1 and a controller 70 that controls the rotation of a left-side motor 60a, which drives a left-side endless track, and a right-side motor 60b, which drives a right-side endless track, according to the operation of an operating stick 20 that is disposed on the operation panel 11. The operating stick 20 of the operation panel 11 is composed of: an operating stick body 21 that can be tilted only in one axial direction back and forth from the neutral position; a left-swivel switch 24; a right-swivel switch 25; and an enable switch 22 that enables the operation of the switches. The switches are arranged at positions on the operating stick body 21 where the left-swivel switch 24 and/or the right-swivel switch 25 can be operated while the enable switch 22 is pressed with fingers gripping the operating stick body 21.

A traveling operation device of a crawler-type aerial work platform including an operation of an enable switch by one hand is provided. An enable switch and a changeover switch are disposed on an operation rod main body at positions where the enable switch and the changeover switch are operable by fingers gripping the operation rod main body of an operation rod during traveling so that all of them are operable by one hand. When a controller receives a switching command signal in accordance with the operation of the changeover switch in a state of usual travel control according to tilt of the operation rod in front-rear and right-left directions, the controller stops the usual travel control to transition the usual travel control to spin turn control that rotates motors in mutually opposite directions and turns the platform on the spot.

A steering system includes a first wheel and a second wheel laterally spaced apart from the first wheel, and a third wheel and a fourth wheel laterally spaced apart from the third wheel. The first wheel is rotatably coupled to a first knuckle and the second wheel is rotatably coupled to a second knuckle. The third wheel and the fourth wheel are both pivotally fixed in a forward-aligned orientation. The steering system includes a first tie rod having a first end pivotally coupled to the first knuckle and a second end pivotally coupled to a mechanical linkage, a second tie rod having a first end pivotally coupled to the second knuckle and a second end pivotally coupled to the mechanical linkage, and an electrical actuator coupled to the mechanical linkage. The mechanical linkage is arranged in front of the electrical actuator relative to a travel direction.

A variable shape three-dimensional structure includes: an upper frame; a lower frame; and a longitudinal coupling member that couples the upper and lower frames. Each of the frames includes cross units and an end coupling portion. Each cross unit is formed by two rigid members crossing each other and pivotally coupled together. The end coupling portion pivotally couples the ends of the rigid members of the cross units. The longitudinal coupling member includes a bent unit comprising a first and second bent rigid members, and a bent portion coupling shaft. The first and second bent rigid members are bent in a V-shape. The bent portion coupling shaft pivotally couples the bent portions of the first and second bent rigid members. The upper end of the bent unit is coupled to the upper frame and the lower end of the bent unit is coupled to the lower frame.

A lift device includes a base, a platform that is repositionable relative to the base between a fully raised position and a fully lowered position, and a scissor assembly coupling the base to the platform. The scissor assembly includes a scissor layer including a first scissor arm pivotally coupled to a second scissor arm. The first scissor arm is configured to rotate relative to the second scissor arm about a middle axis that extends laterally. A pulley is coupled to the first scissor arm. A tensile member is wrapped around the pulley and coupled to the second scissor arm. An actuator is configured to vary a working length of the tensile member such that the first scissor arm rotates relative to the second scissor arm to move the platform relative to the base.

A light weight plastic liner adapted for receipt over an aerial lift basket. The lift basket mounted on a wheeled boom or scissor lift. The liner includes a floor cover and four side covers for covering an inside and an outside of four sides of a frame on the lift basket. Also, the liner includes a removable door cover for covering a hinged door on the lift basket. Further, the liner includes a bungee cord in a bottom seam of the liner for holding the liner in place on the lift basket.

A platform assembly includes a work platform including a platform floor and a safety rail extending from the platform floor to a rail height, and a primary sensor unit secured to the work platform and positioned adjacent one of the platform floor and the safety rail. The primary sensor unit is configured to monitor an area from the platform floor or from the safety rail to a space above the rail height and forward and aft of the work platform. The platform assembly enhances protection for an operator from sustained involuntary operation resulting in an impact with an obstruction or structure.

A hydraulic control system for linear actuation that provides a bypass flow during startup of a lifting command, provides a split flow between a cylinder and a reservoir once a minimum operating speed of a pump has been reached, and provides complete flow to a cylinder after the minimum operating speed of the pump has been reached. This is achieved through control of a flow control valve and a proportional flow control valve by a processor.

A lifting mechanism has a descending mode including an energy-regeneration mode and a non-energy-regeneration mode. The lifting mechanism includes: a battery, an electric machine, a hydraulic pump, an oil tank, a hydraulic cylinder, a work platform and a flow limiting valve. In the energy-regeneration mode, the hydraulic fluid drives the hydraulic pump to operate as a hydraulic motor, thus in turn driving the electric machine to operate as a generator and charge the battery. In the non-energy-regeneration mode, the flow limiting valve limits the maximum of the descending speed of the work platform. In the present application, the flow limiting valve is used to provide throttling resistance to limit the maximum of the descending speed of the hydraulic fluid, thus in turn defining the maximum of the descending speed of the work platform. Therefore, in the present application, by using the flow limiting valve to define the maximum of the descending speed of the work platform, the safety problem due to an accelerated descent during descending of the work platform may be solved, and thus the safety of the lifting mechanism may be ensured.

In particular embodiments, a sheetrock robot may be an autonomous (or semi-autonomous) system comprising a drive base, lift assembly, load Manipulator, and screw gun assembly. In particular embodiments, the sheetrock robot's functions may include, for example: (1) taking a piece of sheetrock off of a stack; (2) picking it up and transporting it to a desired location; (3) lifting and manipulating it into position using the load manipulator; (4) detecting studs; and (5) attaching it to a studded wall with sheetrock screws.