It is often necessary to unfold the integral carrying case of a device such as a portable electronic instrument comprising an upper and lower module. However if it is necessary upon unfolding the case to move apart the modules a limited distance while maintaining their relative alignment the common scissor-slider mechanism will not suffice inasmuch as the scissor mechanism does not latch on retraction and rotation. The disclosed invention provides a scissor-slider mechanism that extends without constraint in the usual fashion, but upon retraction and rotation about the slider axis required for folding the scissor-slider mechanism self-latches, keeping the upper and lower modules from separating.