Abstract: A crane/load safety shackle that includes a yoke having a slot that opens along one side edge of the yoke, and a buckle opening for securing the yoke to a crane load line such that the slot opens downwardly. A pin moveably slidably extends laterally across the slot for closing the slot and supporting a load carried by the shackle. A linear actuator and remote control electronics are mounted on the yoke and coupled to the pin for selectively extending the pin across the slot to support the load carried by the shackle, and retracting the pin from the slot so as to release the load. In the event that the load is supported by the pin and thus exerts lateral forces on the pin, the actuator has insufficient power to withdraw the pin from the slot against such lateral forces applied by the load, so that the load will not be inadvertently released.

Abstract: A conveyor system comprising a platform positioned above and spaced from a building roof for receiving a motorized or manual stone ballast transport cart, and a conveyor positioned beneath the platform for receiving ballast stones unloaded from the cart and conveying the stones over the edge of the roof. The platform is essentially flat and parallel to the roof and includes two ramps positioned at opposite ends of the platform, an opening located directly above the conveyor for permitting passage of ballast stones from the cart to the conveyor, and a grate in the opening with through openings in the grate large enough to permit passage of ballast stones and small enough so that the grate provides a path for the removal machine over the opening. The conveyor is an endless belt conveyor and is driven by a drive belt connected to an internal combustion engine.

Abstract: A selectively positionable extension for an elevated walkway includes a planar ramp mounted by rollers to a frame and coupled to the frame by a selectively extensible hydraulic ram. The frame itself is supported by a second ramp for controlled vertical positioning. A pair of handrail gates are pivotally mounted on the ramp frame at opposed lateral sides thereof, and engage guide channels in the ramp side edges for automatically opening and closing the handrail gates as the ramp is extended from and retracted into the frame. The guide channels are so constructed that the handrail gates open and close from overlapping positions without interference. The entire extension is provided as a modular assembly which may be readily incorporated into existing or new walkway constructions.