Automatic release device for lifting slings

摘要

An automatic sling release serving for the automatic disengagement of a sling, such as a chain, a rope, or a strap from a hoisting hook at the moment of relieving the sling of the weight of the load. The device has a load sustaining body with a first, sling engaging hook thereon. A releasing arm is pivotally mounted on the body, the releasing arm having a portion thereof in the form of a second hook positioned close to the first hook and partially overlapping it. The second hook has two working faces, i.e., an upper sling end engaging face and a front thrusting face, in the basic unloaded position of the releasing arm the front thrusting face projecting beyond the outer edge of the first hook on the load sustaining body. The application of a sling end to the upper face of the releasing arm and the subjection of the device to a load results in the swinging of the releasing arm to its loaded position wherein it partially clears the first hook and the transfer of the sling end from the upper face of the releasing arm to the first hook. Upon the release of the pull of the load upon the body, the releasing arm swings so that its front thrusting face pushes the sling end off the first hook.