Closure fasteners – Bolts – Sliding
Reexamination Certificate
1999-07-02
2001-03-06
Dayoan, B. (Department: 3627)
Closure fasteners
Bolts
Sliding
C292S336300
Reexamination Certificate
active
06196599
ABSTRACT:
The present invention relates to door latches which are opened by pushing a lever on one side of a door, or pulling a lever on the opposing side of a door whereby movement of one of the levers causes a locking bolt to be withdrawn into its housing, and in particular the invention relates to the handles therefor.
BACKGROUND OF THE INVENTION
Push/pull door latches have been found particularly suitable for use on doors to hospital rooms and the like which typically open into the room. A hospital door provided with a push/pull type latch is opened from the outside by applying pressure to the push side of the latch, and opened from the inside by pulling on the pull side of the latch. A hospital technician may enter a patient's room while carrying an armload of medical equipment by merely applying pressure to the push side of the latch, thereby unlatching the door and pushing it open. Conversely, a patient who may have limited use of his or her arms because of the presence of a cast or the like, can unlatch a door and open it from the inside by pulling on the inside handle, an effort requiring a minimum of dexterity.
A number of push/pull type latches are available, and two typical examples can be found in Toledo, U.S. Pat. No. 5,085,474, and Walls, U.S. Pat. No. 5,403,047.
Push/pull door latches include a slide bolt which is movable from an extended/latched position to a retracted/release position, and a cam which is rotatable between a first position and a second position. When the cam is in the first position, a slide bolt in the door latch is in the extended/latched position. When the cam is rotated to the second position, the slide bolt is moved to the retracted/release position. The latch further includes a lever having a central fulcrum, one end of which serves as the handle, and the opposing end of which has a threaded foot added thereto by drilling and tapping that end. The foot is positioned against the cam. The handle is movable from a first position in which the cam is in its first position, and the slide bolt is extended, to a second position thereby rotating the cam to its second position, and retracting the slide bolt.
The handles for such push/pull type door latches are typically cast metal and require stops to prevent the rotation of the handle through a greater arc than that bounded by the first and second positions. Existing castings for handles must be drilled and machined to receive the stops. Such stops are in the form of pins and are identified by indicia number
38
in the patent to Walls, and are not shown in the patent to Toledo. A study of the specification and
FIG. 1
of Toledo, however, reveals that the left handle
18
is free to rotate clockwise, and the right handle
18
is free to rotate counterclockwise unless such movement is prevented by a stop. Handles constructed in accordance with Toledo must also be drilled and machined to receive the stops.
To simplify the construction of such a push/pull type door latch, it would be desirable to provide a handle and a handle mounting assembly for a push/pull handle which would not require that the cast metal handle be machined to receive such stops. Specifically, it would be most desirable to provide a handle for a push/pull door latch which would not require the insertion of stops in the handle as a step towards the assembly of a door latch.
SUMMARY OF THE INVENTION
Briefly, the present invention is embodied in a push/pull latch for use on a door having a planar surface. The latch has a slide bolt which is movable from a first extended/latched position to a second retracted/release position, and a cam which is rotatable about an axis perpendicular to the surface of the door. The cam is rotatable from a first position in which the slide is in the extended/latched position to a second position in which the slide bolt is in the retracted/release position. The latch further has a first spring for urging the bolt from the second position to the first position such that the bolt is in the first position unless it is retracted by a force, such as is applied by the cam, to the second position.
In accordance with the present invention, a unitary base plate has a mounting portion and opposing side panels, with the mounting portion positioned against the surface of the door. The cam is mounted on a shaft perpendicular to the surface of the door and the shaft extends through the mounting portion of the base plate. To rotate the cam to the second position, a second cam is mounted on the end of the shaft which extends through the base plate, and the second cam is engaged by one end, or foot, of a lever arm. The lever arm has a central fulcrum which is pivotally mounted between the opposing panels of the unitary base plate, and the opposite end of the lever arm is a handle which is pushed or pulled to force the foot against the second cat to retract the bolt. The lever arm is movable from a first position to a second position thereby causing the foot to move the cam from its first position to its second position, and a second spring urges the lever arm from its second position, wherein the bolt is retracted, to its first position, wherein the bolt is extended. In accordance with the present invention, the lever arm is made of a unitary piece of material and includes a first stop for contacting the base plate when the lever arm is in its first position to prevent movement of the foot away from the cam when the cam is in its first position.
The lever arm also includes a second stop cast therein which will contact the base plate when the lever arm is in the second position to prevent further rotation of the lever after the cam has reached its second position.
REFERENCES:
patent: 2108359 (1938-02-01), Accardi
patent: 2228979 (1941-01-01), Schrader
patent: 2287446 (1942-06-01), Parsons
patent: 3698215 (1972-10-01), Truhon
patent: 4003593 (1977-01-01), Wilzig
patent: 4007954 (1977-02-01), Erickson
patent: 4629228 (1986-12-01), Marko
patent: 4986583 (1991-01-01), Campbell
patent: 5609372 (1997-03-01), Ponelle
Architectural Builders Hardware Manufacturing Inc.
Dayoan B.
Estremsky Gary
Patnaude & Videbeck
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