Miscellaneous hardware (e.g. – bushing – carpet fastener – caster – Checks and closers – Liquid
Reexamination Certificate
1998-10-30
2001-07-17
Knight, Anthony (Department: 3626)
Miscellaneous hardware (e.g., bushing, carpet fastener, caster,
Checks and closers
Liquid
C016S058000, C016S289000, C016SDIG002, C251S048000, C251S333000, C137S904000
Reexamination Certificate
active
06260236
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to back checking arrangements, and more particularly, to a hydraulic back checking arrangement for an automatic door closer.
There are currently available several types of door closing mechanisms which provide a means for regulating the opening movement of a door and to prevent an over extension of the door opening commonly referred to as back checking.
In U.S. Pat. No. 5,050,268 issued to the inventor of the present application, a back checking arrangement is provided in a door closer which includes a loosely held resilient cushion bar which is engaged by a metallic shield abutting sliding cam plates during a final few degrees of opening of a door to provide an increasing resistance against further opening of the door. The shield engages a solid, but resilient cushion bar approximately 4° prior to a normal full open position of the door. Selective thickness of the cushion bar provide either a 90° full open position of the door or a 105° full open position of the door without additional adjustment.
U.S. Pat. No. 4,064,589 to Bejarano, et al discloses a door closer in which an adjustable valve
132
is provided to regulate the back checking of the door which provides an adjustable shock absorber for the door which provides an adjustable shock absorber for the door as it reaches the fully opened position. This patent also discloses the use of a cushioning pad
157
to cushion a rearward movement of the carrier plate against the rear wall of the cam housing upon abrupt opening of the door past a normal/full open position. However, no means of attachment for the cushioning pad are disclosed.
U.S. Pat. No. 3,675,220 to Jentsch discloses a hydraulic cushioning device screwed through the door closer housing at a rear wall of the door closer housing, wherein a door closer cam forces plate-like members against the hydraulic cushioning device to slow the final stages of opening of the door. Mechanical energy of the door is dissipated to slow the door opening by throttling hydraulic fluid passing from the hydraulic cushioning device into the door closer housing, during compression of the hydraulic cushioning device.
U.S. Pat. No. 3,701,180 to Jentsch, et al discloses a door closer wherein a stud assembly comprising a compressible material replaces the hydraulic cushioning device disclosed in U.S. Pat. No. 3,675,220. Similar to U.S. Pat. No. 3,675,220, the study assembly is screwed through the housing.
U.S. Pat. No. 3,246,362 to A. Jackson discloses a door closer which relies on a compression of springs
31
as a back checking restraint and also relies on engagement between a cam
51
and cam follower rollers
43
,
44
and
45
to provide a stop at a full open position of the door.
A back checking device which comprises a loosely captured cushion bar which provides an increasing resistance to the opening of a door during the last few degrees of travel until reaching a normal full open position, is new to the art.
SUMMARY OF THE INVENTION
The present invention provides an improved back checking arrangement for the closing of the door in a door closer of a type described above in which there is a cam plate which slides longitudinally within the body of the door closer as the door is open and closed. The present invention also has utility in other environments and is not limited to use in a door closer. In many different types of constructions one member moves towards another and that movement must be slowed down and stopped. The present invention may find utility in many such constructions, particularly where it is possible to use a relatively non-compressible fluid in association with the back checking arrangement.
In a preferred embodiment disclosed in detail herein, a cushion bar fabricated of a shaped and ported resilient material is easily, loosely captured at a rear wall of the housing. A metallic shield, which is engaged to two cam follower rollers and abuts the cam plates facing the cushion bar, compresses the cushion bar when the door is opened to within a few degrees of a normal full open position. Such a normal full open position generally is selected as either 90° or 105° relative to the plane of the door jam, or the door in a closed position. The term compression, with respect to the cushion bar includes a movement in which the bar changes shape, as by flowing, but even if the solid material of the bar does not change volume.
When the door is opened to within the last few degrees of its permitted arc of travel, preferably approximately 4°, the shield will engage the cushion bar and further opening of the door will begin compression of the cushion bar. The resilient cushion bar is positioned in a chamber filled with a liquid, such as hydraulic fluid. The cushion bar has internal chambers which fill with liquid and which chambers are ported to the exterior of the bar through relatively small passages. As the door is continued to be opened through its last few degrees of travel, resistance to such travel is provided by the cushion bar, which resistance increases as the cushion bar is compressed, thus restricting the flow of hydraulic fluid out of the chambers, making the cushion bar itself less compressible.
This cushion bar arrangement provides the function of a back check valve without requiring expensive machining of the door closer body for the acceptance of a fluid-type valve and the necessary porting of hydraulic fluid as is required by the use of a reverse check valve such as that disclosed in U.S. Pat. No. 4,064,589, discussed above.
Also, the cushion bar arrangement of the present invention does not require expensive machining of the door closer body for the acceptance of screwed-in cushioning devices, such as disclosed in U.S. Pat. No. 3,675,220 and U.S. Pat. No. 3,701,180, discussed above. The deletion of devices which must be screwed into the door closure housing further provides the advantage of avoiding leakage problems, since the interior of the door closer housing is filled with a hydraulic fluid under pressure. Threaded connections into the door closer housing invite leakage problems.
As mentioned above, the cushion bar is loosely captured within the door closer housing at the rear wall of the housing as opposed to adhesively or mechanically fixing the cushion bar to the rear wall of the housing. This arrangement provides an efficient and economical approach to assembly or to replacement of the cushion bar. Differently sized dimension bars, or bars having different hardness and compressibility values can be provided in accordance with the present invention to allow for full open door angles at different positions, such as 90° or 105° and to provide different resistance responses to the opening of the door.
The present invention can be utilized in any door closer in which the cam plates slide within the door closer body and have a position close to a wall of the closer body.
REFERENCES:
patent: 1095370 (1914-05-01), Bardsley
patent: 1177642 (1916-04-01), Lonbom et al.
patent: 1833121 (1931-11-01), Norton
patent: 1986744 (1935-01-01), Muxworthy
patent: 2114455 (1938-04-01), Pipia
patent: 2158417 (1939-06-01), Garrison
patent: 2230661 (1941-02-01), Wennmann
patent: 2615708 (1952-10-01), Rouverol
patent: 2650386 (1953-09-01), Edwards
patent: 3135991 (1964-06-01), Ellis
patent: 3246362 (1966-04-01), Jackson
patent: 3675270 (1972-07-01), Jentsch
patent: 3701180 (1972-10-01), Jentsch et al.
patent: 3979790 (1976-09-01), Chiarappa
patent: 4003102 (1977-01-01), Hawks
patent: 4064589 (1977-12-01), Bejarano et al.
patent: 4333270 (1982-06-01), Catlett
patent: 4462437 (1984-07-01), Prada
patent: 4483044 (1984-11-01), Johnston et al.
patent: 4486917 (1984-12-01), Johnston et al.
patent: 4502180 (1985-03-01), Harrison et al.
patent: 4762149 (1988-08-01), Pickl
patent: 4773125 (1988-09-01), Watabe
patent: 4979261 (1990-12-01), Lasier et al.
patent: 5050268 (1991-09-01), Toledo
patent: 5272787 (1993-12-01), Salena et al.
patent: 5375813 (1994-12-01), Rozinsky
patent: 5601275 (1997-02-01), Hironaka
patent: 5802670 (1998
Jackson Corp.
Knight Anthony
Sonnenschein Nath & Rosenthal
Williams Mark
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