HYDRAULIC LOCK-SPRING Russian patent published in 2004 - IPC

FIELD: medicine; transport. SUBSTANCE: invention relates to hydraulic locks-springs designed for stepless tilting and return of armchair backrests into initial position and fixing backrests within the limits of their travel. It can be used also for changing angle of tilting of panels in medicine equipment and for opening and closing of windows, doors and hatch covers in vehicles and rooms where fixing of working member is inclined position and its stepless return into initial position is required and reliable operation small weight and overall dimensions should be provided at no routine maintenance and at self-contained operation. Proposed hydraulic lock-spring for returning tilted armchair backrest into initial position and its fixing within the limits of its travel has hydraulic cylinder with two spaces communicating through channel, piston and device to fix hydraulic cylinder within the limits of travel, pusher, button and spool valve. Spool valve is provided with cylindrical sealing surface changing into truncated cone surface and is hydraulic coupled with spaces of hydraulic cylinder made to suit different cross section areas of piston and to shift pusher and spool valve within the limits of travel relative to piston. Pusher and spool valve are interconnected through spaces of hydraulic cylinder when button is pressed to stop, with provision of metered liquid flow through cross section of spool valve and said channel from one space of hydraulic cylinder into the other, proportionally to displacement of spool valve and regulation of speed of return of hydraulic cylinder into initial position. EFFECT: simplified design, reduced weight and overall dimensions of hydraulic lock-spring, possibility of control of speed of return into initial position. 1 dwg