Abstract:
A pneumatically-operated hoist is operated through an automatic, pneumatic control system. The operation of the hoist is initiated through an external signal for the pneumatic control system by means of which the hoist is automatically directed through a plurality of sequential steps. The hoist preferably has at least two remotely-positioned bleed elements which are operated through the pneumatic control elements to control the hoist pressure at predetermined values in a manner such that an operator can manipulate a load with the hoist in a desired manner without having to operate any manual controls at all. The control system also is equipped with a bleed element which opens to slowly bleed the hoist in the event of air failure, so that a load carried by the hoist can be safely lowered.
Abstract:
Load-handling apparatus is provided which includes a safety interlock to prevent the disengagement of a load when the apparatus is in an operative condition to balance or raise the load. The apparatus includes a fluid-operated hoist and a fluidoperated, load-engaging unit. A blocking valve is provided which is responsive to pressure of fluid for the hoist, which valve presents the load-engaging unit from disengaging the load when the pressure is at least equal to a predetermined value which is usually sufficient to at least balance the load.
Abstract:
Improved drive apparatus for moving an object along a predetermined path is provided. The object to be moved is supported and guided by a member which also establishes the predetermined path with the drive apparatus moving the object between at least two given positions on the path. The drive apparatus constitutes a fluid-operated cylinder and piston combination which is effective to operate a cable drum and correspondingly move a cable which is connected to the object to be driven. The fluid-operated apparatus moves the object along the path toward the apparatus when the cable is under sufficient tension, while other means are provided for moving the object in the opposite direction. If the path is at an angle to the horizontal, the object can be moved in the direction away from the fluid-operated apparatus by gravity; if the path is horizontal or substantially so, a fluid-operated tensioning device can be provided for moving the object away from the fluidoperated apparatus.