Cylinder piston device

In an apparatus including a stationary base member and a movable member pivotally connected to the base member for movement relative thereto through a first normal operational range of a movement;

• a cylinder member having an axis, a circumferential wall and two ends, said cylinder member defining a cavity therein between said two ends;
• a piston rod member extending through one end of the cylinder member;
• a piston unit carried by said piston rod member internally of said cylinder member;
• piston rod guiding and sealing means for sealingly guiding the piston rod member through said one end of the cylinder member for telescopic movement relative to the cylinder member throughout a second normal operational range of movement of said piston unit corresponding to said first operational range of movement;
• said second normal operational range of movement being less than the full possible range of movement of said piston unit relative to said cylinder member;
• a volume of pressurized fluid within said cavity and acting on said piston rod member;
• first means for pivotally connecting the free end of the cylinder member to one of the base member and the movable member;
• and second means for pivotally connecting the free end of the piston rod member to the other of the base member and the movable member;
• the improvement comprising:
• at least one of said first and second connecting means being destroyable or deformable upon the occurrence of at least one of excessive temperature or excessive fluid pressure within said cylinder so as to free said gas spring from connection to at least one of said base member and said movable member, respectively, and thereby permit said piston unit to move farther outward of said cylinder member under the force of said pressurized fluid to a first pressure-reduction position;
• means for permitting escape of fluid from said cavity under emergency conditions, said fluid escape means being located at least in part outside of the full possible range of movement of said piston unit outward relative to the cylinder member;
• the emergency fluid escape means including (1) at least one fluid passage coupling said cavity to atmosphere, (2) means for sealing said at least one fluid passage against fluid flow therethrough during normal operating conditions and for opening said at least one passage for fluid flow therethrough in emergency conditions, and (3) means for maintaining said fluid passage sealing means and said at least one fluid passage in mutually sealing relation with one another against the pressure of said fluid under normal operating conditions and for permitting axial movement of at least one of said fluid passage sealing means and said at least one fluid passage out of said mutually sealing relation with the other of said fluid passage sealing means and said at least one fluid passage under the action of said fluid pressure upon the occurrence of emergency conditions;
• and
• said maintaining means permitting said axial movement in response to the increase in at least one of temperature and pressure beyond respective, predetermined values, said respective predetermined values being greater than the respective values of temperature and pressure at which said at least one of said first and second connecting means is destroyable or deformable to free said gas spring.