摘要 |
A linearly displaceable element (e.g. a piston 21 in a fluid cylinder 20) is secured to one door by a piston rod extension 22a, and has a threaded aperture 30. A collar 31 with an oppositely threaded aperture 32 is connected to the other door. A rod 27 has two spaced regions 28,29 with opposed threads, engaging said two apertures 30,32. Displacing the element 21 causes the rod 27 to rotate, which displaces the collar 31 in the opposite direction from the element 21. <IMAGE> |