Patent ID: 6164429
Filing Date: 2000-12-26
Classification: B65G,F15B,F16C

Abstract:
A pneumatic pop-up unit comprising:a cylinder housing having a bottom wall and a side wall defining an internal volume having an open top;the side wall extending upwards from the bottom wall and extending outwards away from the internal volume to form a cylinder housing top wall;a piston slidably received in said housing, said piston having a bottom wall and a side wall defining an internal volume and having an open top;a contact element held within the internal volume of the piston and at least partially extending above the open top of the piston;a seal attached to the outside surface of the wall of the piston about the circumference thereof, configured and arranged to form a substantially air-tight barrier with the inside surface of the side wall of the cylinder housing, wherein the bottom wall of the piston, and the seal form a substantially air-tight volume with the bottom wall and side wall of the cylinder housing;a cap attached to the open top of the housing, the cap having a flange and a central opening having a descending guide channel sized to slidably receive the outside surface of the side wall of the piston, wherein the cap extends outwards along the length of the top wall and then extends downwards and inwards along the top wall towards the side wall and wherein the cap is secured about its circumference to the top wall of the housing by a single-seam crimped, rolled, coined, spun or swaged joint;a compression spring for biasing the piston toward the bottom of the cylinder housing; wherein gas under pressure can be admitted to the sealed volume to elevate and suspend the piston against the bias of the spring such that the contact element is partially extended above the cap.