Locks – Special application – For closures
Reexamination Certificate
1999-08-23
2001-03-06
Boucher, Darnell (Department: 3627)
Locks
Special application
For closures
C292SDIG004
Reexamination Certificate
active
06196034
ABSTRACT:
FIELD OF THE INVENTION
The invention is generally related to latches and latch assemblies, and in particular to latches and latch assemblies for use with slidable partitions such as doors and gates.
BACKGROUND OF THE INVENTION
Latch assemblies, or latches, are commonly used to engage movable partitions such as doors or gates with other structural members, e.g., posts, walls, or panels, or other doors or gates. One use of a latch, for example, is in connection with a slidable partition such as a sliding gate.
A predominant use of a slidable partition is in selectively providing access to an enclosed or secured area To this extent, oftentimes a lock is used in connection with a latch on a slidable partition to prevent the slidable partition from being opened by an unauthorized party. However, many latch and lock designs are susceptible to tampering, which may enable an unauthorized party to defeat a latch and/or lock to gain entry through the slidable partition.
For example, a number of sliding gate designs engage with a structural member (e.g., a fixed post or other partition) using a locking mechanism that operates a latch member to engage with a cooperative keeper on the structural member. The latch member typically projects outwardly from an end surface of the sliding gate in the direction of movement of the sliding gate. The locking mechanism is capable of moving the latch member between an unlocked position, where the latch member does not engage with the keeper, and a locked position, where the latch member engages with the keeper to prevent the sliding gate from disengaging from the structural member. Moreover, oftentimes the latch member is spring-loaded such that, when the locking mechanism is locked, but the sliding gate has not yet been moved to its closed position, the latch member deflects from its locked position to its unlocked position as the sliding gate is closed, and then springs back to the locked position once the sliding gate is moved to the fully closed position. Opening of the sliding gate requires actuation of the locking mechanism to move the latch member from the locked to the unlocked position.
While a spring-loaded latch member simplifies the operation of a sliding gate, such a latch member also often facilitates tampering by unauthorized parties. Specifically, oftentimes it is possible to access the latch member even when the sliding gate is closed, possibly permitting the latch member to be manually deflected to its unlocked position independent of the locking mechanism. For this reason, a significant amount of effort has been expended in the area of protecting a spring-loaded latch member from unauthorized tampering.
Conventional designs typically incorporate various guards to prevent external access to a spring-loaded latch, typically including cooperative members having opposing recesses and projections that serve to restrict external access to one or more sides of a latch. A number of designs do not, however, restrict access to all sides of a latch, and thus present a relatively greater security risk. Other designs that do restrict access to all sides of a latch are typically constructed of somewhat complicated interlocking members, which are more difficult and costly to manufacture. Further, in some designs the interlocking members may still provide gaps that an enterprising party may be able to exploit to gain unauthorized access through the gate. Moreover, many conventional designs are difficult to install or retrofit on existing structures.
Therefore, a significant need continues to exist for an improved mechanism for restricting access to a latch for a slidable partition such as a sliding gate, particularly for a mechanism that is less expensive and complicated, and more secure, than conventional designs.
SUMMARY OF THE INVENTION
The invention addresses these and other problems associated with the prior art by providing a latch assembly that incorporates a pair of overlapping tubular guard projections respectively secured to a pair of opposing structural members, at least one of which is disposed on a slidable partition. As the projections are tubular, the projections isolate the enclosed area within the projections from all sides. Moreover, as one projection overlaps the other, no gaps are present that could otherwise permit access to the enclosed area within the projections. As such, whenever a latch member projects through the enclosed area within the overlapping projections, the latch member is substantially protected from unauthorized tampering.
Typically, one of the overlapping tubular guard projections is secured to the end surface of one of the structural members, while the other projection is secured to a base plate of a keeper secured to the other structural member. Each projection extends generally along an engagement axis along which the slidable partition slides, with the projection coupled to the end surface circumscribing a latch member receiving aperture in the end surface. Both the end surface and the base plate oppose one another and extend perpendicular to the engagement axis.
Furthermore, in some embodiments, the opposing projections have generally the same length along the engagement axis such that, when the structural members are secured to one another, the opposing projections overlap generally throughout an exposed region between the base plate and the end surface. As such, the enclosed area is protected on all sides by two layers substantially throughout the exposed region. In addition, in some embodiments, the overlapping tubular guard projections are suitable for retrofitting an existing latch assembly for use in securing a sliding gate to a fixed structural member, simply through mounting a first tubular guard projection to the end surface of the sliding gate, with the projection circumscribing a latch member receiving aperture, and mounting a keeper including a second tubular guard projection to the fixed structural member. In still other embodiments, a projection may be used to house a padlock adaptor that replaces a latch member and projects through the latch member receiving aperture to permit a padlock to be used to lock the slidable partition in lieu of a lock assembly.
In still other embodiments, the length of the base plate of the keeper is selected to provide a minimum separation of at least about 4⅜ inches between a lock release on a lock assembly to each of the longitudinally opposing edges of the keeper (such longitudinally opposing edges being defined in a direction generally transverse to the engagement axis). By doing so, the lock release is protected from unauthorized attempts to reach the lock release through any gap between the first and second structural members.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawings, and to the accompanying descriptive matter, in which there is described exemplary embodiments of the invention.
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Multilock Product Literature (1968), 9 pages.
Wireway Husky Product L
Diebold Stephen E.
Lukenbill H. Neil
Boucher Darnell
Wirecrafters, Inc.
Wood Herron & Evans L.L.P.
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