Door hold and release mechanism

A door hold and release mechanism for use with a door closer including a pneumatic cylinder having a reciprocating piston rod comprising, in combination:

• a housing having an open end;
• means for mounting said housing onto said pneumatic cylinder;
• a drop stop having a hole through which said piston rod extends, said hole being of such size as to allow movement of said piston rod through said hole in a first position with said drop stop disposed substantially perpendicular to said piston rod but which restricts movement of said piston rod in a second position when said drop stop is tilted at an angle other than substantially perpendicular to said piston rod;
• a cap button mounted to said open end of said housing;
• a shaft disposed in said housing, said shaft having first and second ends, said first end of said shaft being affixed to said cap button;
• a guide plate mounted inside said housing, said guide plate having an opening for guiding said shaft through said housing:
• a spring mounted between said guide plate and said cap button, said spring exerting a bias pressure on said shaft in a direction opposite to an external force applied to said cap button;
• a draw bar disposed in said housing, said draw bar having a forward and a rearward end, said forward end of said draw bar extending outwardly through said housing and being connected to said drop stop for moving said drop stop alternately between said first and second positions;
• and
• linkage means comprising an elongated cam slot formed within said second end of said shaft and a pin extending through said slot and said rearward end of said draw bar, said slot being inclined at an angle with respect to said draw bar such that said draw bar is forced to move both laterally along with said shaft and in a rearward direction in response to said external force applied to said cap button, thereby causing said drop stop to tilt from said first to said second position on said piston rod.

A door hold and release mechanism for use with a door closer including a pneumatic cylinder having a reciprocating piston rod, comprising, in combination:

• a shaft having first and second ends;
• means for applying a bias pressure on said shaft;
• means for applying an external force to said shaft sufficient to move said shaft laterally in a direction opposite to said bias pressure;
• a drop stop, said drop stop having a hole through which said piston rod extends, said hole being of such size as to allow movement of said piston rod through said hole in a first position with said drop stop disposed substantially perpendicular to said piston rod but which restricts movement of said piston rod in a second position when said drop stop is tilted at an angle other than substantially perpendicular to said piston rod;
• a draw bar having a forward and a rearward end, said forward end of said draw bar being connected to said drop stop for moving said drop stop alternately between said first and second positions;
• and
• linkage means comprising an elongated cam slot formed in one of said second end of said shaft and said rearward end of said draw bar and a pin extending through said slot and the other of said second end of said shaft and said rearward end of said draw bar, said slot being inclined at an angle with respect to said draw bar such that said draw bar is forced to move rearwardly and simultaneously in a direction opposite to that of said means for applying an external force, thereby causing said drop stop to tilt from said first to said second position on said piston rod.