Abstract: A lift system is coupled between a work platform and a mast on a mast lift. The lift system includes an overload clutch that slips upon an overload on the lift system, an overrun brake that prevents the lift system from running beyond a fully lowered position and that prevents the lift system from running if the platform is hung up, and an emergency brake. The lift system is safe and lightweight and is effective for controlling a position of the work platform on the mast.

Abstract: A lift system is coupled between a work platform and a mast on a mast lift. The lift system includes an overload clutch that slips upon an overload on the lift system, an overrun brake that prevents the lift system from running beyond a fully lowered position and that prevents the lift system from running if the platform is hung up, and an emergency brake. The lift system is safe and lightweight and is effective for controlling a position of the work platform on the mast.

Abstract: A lift system is coupled between a work platform and a mast on a mast lift. The lift system includes at least one lifting rope connected between the work platform and the mast via an idler roller and a hoist drum connected to the work platform. The idler roller is displaceable between an engaged position and a disengaged position based on an amount of tension on the lifting rope. A spring is connected to the idler roller and urges the idler roller toward the engaged position. A carriage latch assembly includes a carriage latch hook coupled with the idler roller and a pin secured to the mast. When the idler roller is disposed in the engaged position, the carriage latch hook is engageable with the pin.

Abstract: A retractable wheel assembly includes a wheel frame supporting a wheel, and a pivot bracket assembly secured to the wheel frame. The pivot bracket assembly is displaceable between an extended position and a retracted position. A biasing mechanism is coupled with the pivot bracket assembly. The biasing mechanism urges the pivot bracket assembly toward the extended position when the pivot bracket assembly is in the extended position and urges the pivot bracket assembly toward the retracted position when the pivot bracket assembly is in the retracted position.

Abstract: A lift system is coupled between a work platform and a mast on a mast lift. The lift system includes an overload clutch that slips upon an overload on the lift system, an overrun brake that prevents the lift system from running beyond a fully lowered position and that prevents the lift system from running if the platform is hung up, and an emergency brake. The lift system is safe and lightweight and is effective for controlling a position of the work platform on the mast.

Abstract: A slip clutch acts between a shaft and a housing. The slip clutch includes an oil reservoir within the housing and one or more slipping surfaces disposed in the oil reservoir that are keyed to the shaft and possibly alternately to the housing. The slipping surfaces may include stacked plates or washers. Each of the washers includes an oil groove or other structure on one surface thereof that maintains a consistent film of oil on the washer surfaces. The stacked washers slip relative to one another such that the shaft rotates relative to the housing upon an application of torque that exceeds a predetermined torque.

Abstract: A lift system is coupled between a work platform and a mast on a mast lift. The lift system includes at least one lifting rope connected between the work platform and the mast via an idler roller and a hoist drum connected to the work platform. The idler roller is displaceable between an engaged position and a disengaged position based on an amount of tension on the lifting rope. A spring is connected to the idler roller and urges the idler roller toward the engaged position. A carriage latch assembly includes a carriage latch hook coupled with the idler roller and a pin secured to the mast. When the idler roller is disposed in the engaged position, the carriage latch hook is engageable with the pin.

Abstract: A retractable wheel assembly includes a wheel frame supporting a wheel, and a pivot bracket assembly secured to the wheel frame. The pivot bracket assembly is displaceable between an extended position and a retracted position. A biasing mechanism is coupled with the pivot bracket assembly.

Abstract: A slip clutch acts between a shaft and a housing. The slip clutch includes an oil reservoir within the housing and one or more slipping surfaces disposed in the oil reservoir that are keyed to the shaft and possibly alternately to the housing. The slipping surfaces may include stacked plates or washers. Each of the washers includes an oil groove or other structure on one surface thereof that maintains a consistent film of oil on the washer surfaces. The stacked washers slip relative to one another such that the shaft rotates relative to the housing upon an application of torque that exceeds a predetermined torque.