batten clamp

[derekleffew]

1a. A piece of hardware that is the preferred method for attaching wire rope to a horizontal pipe.

1b. For temporary use, a half-coupler with an eye may be used.

2. A very old piece of hardware designed to hang a backdrop by pinching it between two 1x4s. May also be called a sandwich batten clamp, clamshell clamp, or drop holder.
From Stage Scenery: Its Construction and Rigging :

BATTEN CLAMP, OR DROP HOLDER (Fig. 72). A clamp used for attaching drops or borders to a set of lines in preparation for flying them. The jaws of the clamp are designed to open and fit around the wooden batten at the top of a drop. These clamps may be attached or removed rapidly and without damage to the canvas. ($12.50 each). [1972 prices.]

Another variant: http://www.rohcollections.org.uk/Mag...echClamp1.aspx .