Pneumatic door-closer having a closable passage and a regulatable passage

• US 4,817,238 A
• Filed: 06/02/1988
• Issued: 04/04/1989
• Est. Priority Date: 06/02/1988
• Status: Expired due to Fees

• Current Assignee: Gouhill Industrial Co., Ltd.
• Original Assignee: James C. Liu
• Inventors: Liu, James C.
• Primary Examiner(s): Silverberg, Fred A.
• Application Number:
  US07/201,532
• Time in Patent Office: 306 Days
• Field of Search: 16/49, 16/51, 16/52, 16/58, 16/66, 16/72, 16/84, 16/DIG. 9, 16/DIG. 10, 92/181 D, 91/422
• US Class Current: 16/66
• CPC Class Codes: E05F 3/02 with pneumatic piston brakes rotary type E05F3/14
• CPC Class Codes: E05Y 2900/132 Doors
• CPC Class Codes: F16F 9/0218 Mono-tubular units F16F9/0227, F16F9/0236, F16F9/0245 take precedence
• CPC Class Codes: F16F 9/516 resulting in the damping effects during contraction being different from the damping effects during extension , i.e. responsive to the direction of movement F16F9/504 takes precedence
• CPC Class Codes: Y10S 16/10 Spring actuated checks and closers

Abstract

A door-closer has an air cylinder in which a piston rod and a piston body are provided to define first and second sealed chambers. The piston body is sleeved movably on the piston rod and has a tapered bore which is communicated with the second chamber. A closable passage is formed through the piston and communicated with the first and second chambers. A spring-biased seal is disposed in the second chamber and biased to close the closable passage. A regulatable passage is formed through the piston body and communicated with the tapered bore and the first chamber. The piston rod has a shoulder which is movable axially within the tapered bore by rotating the cylinder relative to the piston rod for regulating the air flow between the first and second chambers through the regulatable passage. The spring-biased seal is movable to open the closable passage when the piston body moves in response to the opening of the door. When the door is opened, compressed air flows from the first chamber to the second chamber through the regulatable passage and the closable passage. When the opened door is released, compressed air flows from the second chamber to the first chamber through the regulatable passage.

Claims

1. A door-closer comprising an air cylinder filled with compressed air, a piston rod movable in said cylinder, and an annular piston means sleeved movably on said piston rod and movable sealingly in said cylinder for defining first and second sealed chambers in first and second end portions of said cylinder respectively, said piston means moving from said second end portion of said cylinder to said first end portion of said cylinder when an associated door which is equipped with said door-closer is opened, said piston means including a piston body sleeved movably on said piston rod and having a tapered central bore which is communicated with said second chamber, a closable passage formed through said piston body and communicated with said first and second chambers, a spring-biased seal disposed in said second chamber and biased to close said closable passage, and a regulatable passage formed through said piston body and communicated with said tapered bore and said first chamber, said piston rod having a shoulder which is movable axially within said tapered bore of said piston body by rotating said cylinder relative to said piston rod for regulating air flow between said first and second chambers through said regulatable passage, said spring-biased seal being movable to open said closable passage when said piston means moves from said second end portion of said cylinder to said first end portion of said cylinder in response to opening of said door;

whereby, when said piston means moves from said second end portion of said cylinder to said first end portion of said cylinder in response to opening of said door, increased air pressure in said first chamber urges said spring-biased seal to separate from said closable passage so that compressed air can flow from said first chamber to said second chamber through said regulatable passage and said closable passage;

when said opened door is released, air pressure accumulated in said first chamber urges said piston means to return from said first end portion of said cylinder to said second end portion of said cylinder in such a manner that compressed air flows from said second chamber to said first chamber through said regulatable passage.

2. A door-closer as claimed in claim 1, wherein said piston rod includes a C-shaped retaining element fastened to an end thereof for retaining said piston body on said piston rod.

3. A door-closer as claimed in claim 1, wherein said piston rod includes a rubber sleeve which is sleeved snugly on said shoulder of said piston rod, whereby, said sleeve may be moved to seal said tapered bore of said piston body so as to stop air flow between said first and second chambers through said regulatable passage.

4. A door-closer as claimed in claim 1, wherein said piston rod has an externally threaded portion, and wherein said piston body has an internally threaded portion engaged with said externally threaded portion of said piston rod, whereby, when said cylinder is rotated relative to said piston rod, said piston body moves slowly on said piston rod.