Apparatus and method for increasing the efficiency of a door closer by reducing friction therein
AssigneeSchlage Lock Company LLC
InventorsLynn A. Schmelzer, Thomas R. Lasier
Life of this patent
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Abstract
A door closer has a fluid conduit connecting the high pressure portion of the cylinder in front of the piston with a cavity between the surfaces of the cylinder wall and the piston. This cavity is located at the intermediate lateral surface of the piston at the back side of a gear rack formed on the piston. The variable lateral bias provided by the pressurized cavity counteracts separating forces between the gear rack and a gear pinion caused by the tapered teeth. This decreases friction between the piston and the cylinder and reduces wear throughout the closer mechanism.
Claims11
In a door closer which has a piston within a cylinder with a gear rack formed on said piston and a gear pinion engaging said gear rack, said gear pinion being affixed to a shaft whose axis is perpendicular to said piston and said gear rack, the improvement, in combination with said piston, said cylinder, said gear rack, and said gear pinion, comprising:
- means for providing a variable biasing force to said gear rack in order to counteract a separating force between said gear rack and said gear pinion.
In a rack and pinion gear apparatus movable in conjunction with reciprocation of a piston within a fluid containing cylinder, said rack being formed on one longitudinal wall of said piston an said pinion gear being mounted on a shaft perpendicular to and in meshed engagement with said rack, a device, in combination with said rack and pinion gear apparatus, for counteracting a separating force between said rack and said pinion gear, comprising:
- means for biasing said rack toward said pinion gear, said bias being proportional to said separating force.
A method for biasing a rack toward a pinion in a rack and pinion gear apparatus, having a piston which moves in a fluid containing cylinder in response to movements of said rack, comprising:
- providing a fluid containing cavity against a surface of the rack opposite the surface of the rack upon which gear teeth are formed;
- and
- providing a conduit means between a high pressure portion of said cylinder and said cavity for equalizing pressure therebetween.
Dependencies are inferred from the claim text.