An aerial work platform (AWP) includes a base, a retractable lifting mechanism, a platform, an actuator, and a spring. The retractable lifting mechanism has a first end rotatably coupled to the base. The platform is coupled to and supported by a second end of the retractable lifting mechanism. The actuator is pivotally coupled to the retractable lifting mechanism. The actuator has a piston received within a housing that is movable between a stowed position and a deployed position, where the piston engages and forces the retractable lifting mechanism away from the base to lift the platform away from the base. The spring biases the retractable lifting mechanism away from the base and provides a variable biasing force to the retractable lifting mechanism that increases as the piston approaches the stowed position.

Reduction of minimum turning radius of an aerial work platform. Drive motors are provided to driven wheels of the platform respectively, so that the driven wheels can be independently controlled in terms of rotational speed and rotation direction. When the steering angle of steered wheels is at most a first steering angle, constant velocity control is performed, driving both of the driven wheels in the same rotation direction and at the same rotational speed. When the steering angle exceeds the first steering angle and is at most a second steering angle, differential control is performed, reducing the rotational speed of the driven wheel on the inside in the turning direction relative to the driven wheel on the outside in the turning direction. When the steering angle exceeds the second steering angle, counter-rotation control is performed, counter-rotating the driven wheel that is on the inside in the turning direction.

Systems and methods for a redundant wireless safety system that provides a second level of safety protocol when a worker is exposed to a more dangerous work environment. In an embodiment, such a machine may be configured to perform a specific manufacturing function wherein the machine may include first and second transceivers for maintaining enabling signals for functionality of the machine. The system may further include a base station (e.g., remote control) configured to operate in conjunction with the machine that in turn includes third and fourth transceivers also configured to maintain enabling signals for machine functionality. Machine functionality may be interrupted by an interrupt switch disposed in the machine. That is, the interrupt switch may be configured to enable functionality of the machine if and only if the first transceiver maintains periodic communication with the third transceiver and if the second transceiver maintains periodic communication with the fourth transceiver.

A lift device includes a chassis, a platform disposed above the chassis, a lift assembly coupling the platform to the chassis and configured to move the platform between a lowered position and a raised position, and a stair assembly coupled to at least one of the platform and the chassis, the stair assembly including a first step and a second step. The platform includes a deck defining a top surface configured to support an operator. The stair assembly is selectively repositionable relative to the chassis between a stored position and a deployed position. The stair assembly facilitates access to the deck from the ground when in the deployed position.

A lift device comprises a base, a retractable lift mechanism, a work platform, a linear actuator, and a lift controller. The base has a plurality of wheels. The retractable lift mechanism has a first end coupled to the base and is moveable between an extended position and a retracted position. The work platform is configured to support a load. The work platform is coupled to and supported by a second end of the retractable lift mechanism. The linear actuator is configured to selectively move the retractable lift mechanism between the extended position and the retracted position. The lift controller is configured to monitor at least one lift characteristic associated with the linear actuator and to determine whether an actuator failure has been detected based on the at least one lift characteristic associated with the linear actuator.

A lift device comprises a base, a retractable lift mechanism, a work platform, a linear actuator, and a descent control mechanism. The base has a plurality of wheels. The retractable lift mechanism has a first end coupled to the base and is moveable between an extended position and a retracted position. The work platform is configured to support a load. The work platform is coupled to and supported by a second end of the retractable lift mechanism. The linear actuator is configured to selectively move the retractable lift mechanism between the extended position and the retracted position. The linear actuator has an electric motor. The descent control mechanism is configured to reduce a speed at which the retractable lift mechanism is moved from the extended position to the retracted position.

A lift device comprises a base, a linear actuator, and a rechargeable battery system. The base has a plurality of wheels. The linear actuator is configured to selectively move a work platform configured to support a load between a raised position and a lowered position. The linear actuator has an electric motor. The rechargeable battery system includes a battery, a heating system, and a battery charger. The battery is configured to power the electric motor of the linear actuator. The heating system is configured to selectively provide heat to the battery. The battery charger is configured to selectively charge the battery and to selectively charge the heating system. The heating system is configured to receive power from the battery through a battery power connection and to receive power from the battery charger through a battery charger power connection.

A lift device includes a base, a retractable lift mechanism, a work platform, and a lift controller. The retractable lift mechanism is moveable between an extended position and a retracted position. The work platform is configured to support a load and is coupled to and supported by the retractable lift mechanism. The linear actuator is configured to selectively move the retractable lift mechanism between the extended position and the retracted position. The linear actuator has an electric motor and an electromagnetic brake. The lift controller is in communication with the linear actuator and is configured to determine the load supported by the work platform based on the actuator force applied to the work platform and the height of the work platform.

A lift device includes a lift assembly, a platform, and a controller. The lift assembly is configured to be driven to increase or decrease in length by extension and retraction of one or more actuators. The platform is coupled at an upper end of the lift assembly. The controller is configured to receive a value of a pitch angle and a roll angle of the lift device from an orientation sensor. The controller is further configured to determine a maximum allowable elevation of the platform based on at least one of the value of the roll angle and the value of the pitch angle of the lift device. The controller is further configured to limit operation of the lift assembly based on the maximum allowable elevation of the platform.

A fully-electric scissor lift comprises a base, a retractable lift mechanism, a work platform, a linear actuator, and a battery. The base has a plurality of wheels. The retractable lift mechanism has a first end coupled to the base and is moveable between an extended position and a retracted position. The work platform is configured to support a load. The work platform is coupled to and supported by a second end of the retractable lift mechanism. The linear actuator is configured to selectively move the retractable lift mechanism between the extended position and the retracted position. The linear actuator has an electric lift motor. The battery is configured to apply power to the electric lift motor. The fully-electric scissor lift is completely devoid of moving fluids.