Abstract: An adjustable or similar gripping device includes a shaft and a gripping head which has two jaws, at least one of which is moveable so as to adjust the opening between the jaws of the gripping head. At least one of the jaws has a gear rack which engages a rotatable cog. A spring on the cog urges the jaws into a gripping position. A locking device is provided selectively to prevent movement of the jaw. The locking device includes a locking member which engages between a surface on the cog and a cam located next to the cog. The locking member moves in and out of locking engagement with the cog and the cam.

Abstract: A wrench comprises a handle and a gripping mouth which is defined by two jaws, one of which is fixed and the other movable. The movable jaw is associated with a rack engaging a gear which is rotatably mounted relative to the handle and actuated by at least one spring constantly striving to rotate the gear in a direction such that the jaws are moved towards one another, said gear cooperating with a locking device which can be set in two different positions, a first position in which the gear is freely rotatable, and a second position in which the gear is non-rotatable and in which the gear, in turn, renders displacement of the movable jaw relative to the fixed jaw impossible.

Abstract: A hang stand for persons with injuries to their backs, and especially for such persons who wish to unload their backs, comprises vertically arranged elongated members on a base support having an upper bar extending therebetween and located at such a height that when a person grasps the bar with both hands, the person can hang freely. Further provided is a back support slideably coupled to the elongated vertical members so as to be moveable in a vertical direction but immoveable in a horizontal direction. The back support is arranged to engage a given part of the back of the user to horizontally and immoveably support the given part of the back but permitting vertical movement of the given part of the back when the user grasps the bar and hangs freely. The back support is spring mounted and vertically adjustable. Foot supports on the base support help position the user before hanging.