Patent Application
20160348396
The present invention relates to a lock plate configured to functionally cooperate with a striker plate as a guard for a latch bolt of a spring lock.
In a conventional residential entry door with a spring lock, a vertical stop strip is fixed to the jamb toward the exterior side of the door structure for abutment stopping of the door in the frame. A striker plate is provided on the jamb at a location to be struck by the latch bolt on swinging closure of the door in the frame. For ease of action, the latch bolt has an oblique surface to provide for smooth retraction of the latch bolt as it slides over the striker plate and into a hole provided in the striker plate and door jamb. On an inwardly swinging door, this oblique surface if pushed on from the outside by a foreign object such as a credit card, screwdriver or the like may be used to retract the latch bolt and gain access through an otherwise locked door.
In order to be tamper proof, a conventional spring lock relies on tight installation of a door frame against the edge of a door to leave no room for inserting a foreign object into the gap between the vertical stop strip and the door. Over time, however, doors which are initially installed without excessive gaps between the door and the door frame can suffer from deterioration in their installation due to loose or improperly mounted hinges, shrinkage or warping of the wood, or even setting of the house. Incorrect sizing of doors further adds to the gaps created between doors and their respective door frames. There are repairs that can be made to correct warps and looseness of a door in a door frame but in general no action is taken immediately. The work usually requires taking the door down and is beyond the skills of many home owners and tenants are not motivated. Hence there is a need for a lock plate for guarding the latch bolt in imperfect door lock installations. More particularly, there is a need for a lock plate that is simple to install (e.g., with a screwdriver) without making any modification to existing door lock installations.
In view of the above, it is an object of the present invention to provide a guard for latch bolt of a spring lock. It is another object to provide a guard which is simple to install and which does not require modifiction of an existing door lock installation. It is also an object to provide a guard may be inexpensively made. Other objects and features of the invention will be in part apparent and in part pointed out hereinafter.
In accordance with the invention, a lock plate for a latch bolt of a spring lock is formed from a unitary member. The lock plate has a face portion with first and second ends and upper and lower edges defining a horizontal and vertical dimension respectively. The face portion includes a recess for receiving a latch bolt and spaced mounting holes with a tongue along a side of the recess towards the second end. The first end of face portion merges into an inwardly curved lip portion and the second end has an L-shaped end with an outwardly and forwardly curved arm. The lock plate is configured to nest on a striker plate of a spring lock with the tongue received in a recess provided in the striker plate for receiving a latch bolt and with the mounting holes in the face portion of the lock plate in registry with mounting holes in the striker plate. The same screws by which the striker plate is attached to a door jamb may be used to attach the nested combination.
in one embodiment, the L-shaped second end has a flat leg is configured to fit along an inside edge of a stop strip of the door jamb. In other embodiments, the recess for receiving a latch bolt and spaced mounting holes are towards the second end of the face portion. In some embodiments, the first and second ends of the lock plate are configured to extend beyond the striker plate.
Usually, the tongue extends from a side of the recess in the face portion proximate the second end and may be either generally perpendicular to the face portion or configured to bend around an underside of the striker plate.
The invention summarized above comprises the constructions hereinafter described, the scope of the invention being indicated by the subjoined claims.
In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated, corresponding reference characters refer to corresponding parts throughout the several views of the drawings in which:
The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. For purposes of description herein, the terms “upper,” “lower,” “left,” “rear,” “right,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in
Referring to the drawings more particularly by reference character,
With continuing reference to
As best seen in
In use, screws 56 for mounting striker plate 16 are removed. Lock plate 30 is configured to nest over striker plate 16 and be attached with the original screws 56 used to attach the striker plate to door jamb 14 with mounting holes 44 in lock plate 30 in registry with mounting holes 58 in striker plate 16. First and second ends 34, 36 of lock plate 30 extend beyond the ends of striker plate 16 and tongue 46 passes through hole 22 in the striker plate and is received in hole 24 in door jamb 14. The installation is easily done by a person with a screwdriver. No special skills are required and renters may add lock plate 30 without authorization as it does not require any modification of the existing door lock installation.
In place, lock plate 30 provides much of the security of a dead bolt without the disadvantages and expense of a dead bolt. As door 10 is closed against stop strip 18, curved arm 52 blocks entry of a foreign object into gap 28 to latch bolt 12. If the gap is smaller than illustrated in
In the above description, numerous specific details are set forth such as examples of some embodiments, specific components, devices, methods, in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to a person of ordinary skill in the art that these specific details need not be employed, and should not be construed to limit the scope of the disclosure. In the development of any actual implementation, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints. Such a development effort might be complex and time consuming, but is nevertheless a routine undertaking of design, fabrication, and manufacture for those of ordinary skill. Hence as various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
