Abstract: A lifting apparatus for elevating folding roof sections comprises a pair of jackknifing lifting bars. A hoist means transmits a pulling force to the bars, thereby enabling each bar to unfold from a initial folded configuration into an extended straight configuration. The bars elevate first roof sections to an intermediate pitch while unfolding into the straight configuration and while rotating into a generally vertical position with respect to the first roof sections. Remaining roof sections, together with the first roof sections, are elevated to a desired pitch with the bars in the straight configuration by applying additional force. Additional force causes the bars to rotate from the vertical position into a generally horizontal position while lifting both first and second roof sections to the desired pitch. At the start of the lift, all roof sections are horizontally folded and substantially supported on first segments of hinge plates fastened thereto.

Abstract: Apparatus for the superimposition of television images including recorder apparatus for recording and playing back first video signals, image generating apparatus for providing second video signals, drive apparatus for driving the image generating apparatus synchronously with respect to the recorder apparatus responsive to receipt by the drive apparatus of first video signals and signal combining apparatus for superimposing the first and second video signals. Display and/or recording means may be provided for displaying and recording the superimposed video image.