A towing sock or wire rope puller or wire pulling grip is a device that connects to the end of a cable, such as a power cable, in order to pull it through a tube or tunnel.[1] It works by tightening around the cable when pulled, in the same manner as a Chinese finger trap.[2] The towing sock is tubular and made of braided cable, open at one end and closed at the other where it connects to a tow line using an eye splice.[3]
Similar devices include a traction device used to treat a Bennett's fracture, a type of finger or thumb injury.[4]
Also similar is the strain-relief grip which uses woven wire around the end of electrical wiring just before the terminal. It is placed there to prevent the wire from breaking.[5] They are common in "drop" installations where electrical cables are attached to conduit on the ceiling and drop through space down to a machine or receptacle. Generally, the cable is attached to the electrical wiring near the ceiling in a normal manner, but a short distance away from the electrical connection there is a strain relief grip attached to an anchor point on the ceiling to hold the weight of the wire, though if the wire is not particularly heavy, the strain-relief grip may be attached directly to the rigid conduit.[6]