Referring to
Further referring to
Referring to FIGS. 1 to 4,The coupling block 20 includes a pivot shaft 21 extending therefrom so as to be connected to a door which is not shown. A first rod 22 and a second rod 23 are pivot ably connected to the coupling block 20 and respectively inserted in the first and second tunnels 111, 112. A threaded rod 221 is connected to a distal end of the first rod 22 and a first spring 34 is mounted to the first rod 22 and the threaded rod 221. A sleeve 35 has a threaded inner periphery 351 and the threaded rod 221 is threadedly engaged with the threaded inner periphery 351 of the sleeve 35. The sleeve 35 has a flange such that the first spring 34 is biased between a shoulder portion of the first rod 22 and the flange of the sleeve 35. An operation rod 36 has an end thereof rotatably engaged with a hole 151 defined through an end member 15 which seals the first tunnel 111. A knob 360 extends from the end of the operation rod 36 and a polygonal hydraulic cylinder 3600 is defined in the knob 360 so that a tool can be used to rotate the operation rod 36 by engaging the polygonal hydraulic cylinder 3600. The knob 360 is located at a second end of the casing 10 so as to be easily accessed by the users. The operation rod 36 has at least one longitudinal groove 361 defined in an outer periphery thereof and a boss 352 extends from an inner periphery of the sleeve 35 so that the boss 352 is engaged with the groove 361. By the engagement, when the operation rod 36 is rotated, the sleeve 35 is rotated relative to the threaded rod 351 and the first spring 34 is compressed by the movement of the sleeve 35.
A second spring 340 is mounted to the second rod 23 and a piston 24 is connected to a distal end of the second rod 23. An screw caps 14 seals the second tunnel 112.
As shown in
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.