Correct fixing method of chain block hook screw

When the chain hoist is not used in general, the chain block is decoupled when there is no inclined cable, sag, twisted chain, overload, sudden force, and other operation phenomena. This is due to the problem of the fixing method of the screws fixing the ball in the cross beam of the hook. .

The method of fixing the screw is to assemble the 13 rollers. Screw the screws into the bottom of the screw holes with a screwdriver, and then rivet the outer ports of the screws. Under normal circumstances, the dimensions of the screws and the holes in the screw holes are normal. When the screws are screwed into the bottom of the screw holes, the distance between the ends of the screw head and the balls should be equal to the clearance between the balls and the ball ring grooves. When the hook is subjected to gravity, the hook ring groove gives the ball an outward force, and the screw is subjected to the jacking force of the ball outward. When the outer port of the screw hole is not riveted firmly, the screw is withdrawn from the screw hole. Under the action of external force, the ball bearing the shearing force and friction force exits from the screw hole one after another, and the hook and the cross beam of the hook lose the restriction of the ball, and the hook and the cross beam of the hook displace relative to each other in the axial direction of the hook. Disengagement led to accidents.

In order to prevent similar accidents from happening and prevent the screw from exiting from the screw hole, in addition to checking the riveting condition of the screw hole, it is also possible to seal the space of the screw hole in the tail part of the hook beam with tin alloy.