Patent Application
20100096864
The present invention relates to electrically-releasable door latch mechanisms, also known in the art as “electric strikes”; more particularly, to electric strike door keepers including a solenoid release element; and most particularly, to an improved electric strike door keeper assembly wherein activation of a solenoid directly unblocks rotation of a latch mechanism, and wherein an improved faceplate for mounting the electric strike sub-assembly eliminates a torque-related shortcoming of prior art electric strike door keeper assemblies.
Electric strikes for permitting the release of an otherwise latched door are well known in the art. See, for example, Model 4 K 61, available from Fritz Fuss GmbH & Co., Albstadt, Germany; and Model 3234W-26D, available from Trine Access Technology, Bronx, N.Y. 10461 USA.
In a typical prior art electric strike, a keeper protrudes from a housing and is mechanically maintained in position during closing and consequent locking of a door. A body housing the keeper may be mounted to a faceplate on either the door or the frame to equal effect, although frame mounting is commonly preferred for ease in wiring of the assembly into an entry control system. A manual override may or may not be provided. In use, a complementary latch bolt is provided in either the door or the frame, which engages and interferes with the keeper during opening and closing of the door. Typically, the complementary latch bolt is spring-biased and slidable axially, such that progressive contact with the keeper causes axial depression of the latch bolt to permit passage of the latch bolt past the keeper, whereupon the latch bolt is urged into an opening in the strike or faceplate by the bias spring.
Typically, the keeper is pivotably disposed on a first axis transverse to the direction of door closing and opening and is held in latching mode by a spring-biased arm pivotably disposed on a second axis. The arm engages the keeper, blocking rotation thereof. A solenoid is operable to rotate the arm, either directly or via one or more intermediate levers, pivots, and/or springs.
Prior art electric strikes are complex, having numerous moving parts, and are relatively difficult and time-consuming to assemble. Typically, at least one component requires precision milling and further machining, which adds expense.
What is needed in the art is a simple electric strike door keeper assembly having relatively few components that is inexpensive to manufacture and easy to assemble.
It is a principal object of the present invention to reduce the manufacturing cost of an electric strike door keeper assembly.
Briefly described, an electric strike door keeper assembly in accordance with the present invention comprises a body formed of first and second body parts that interlock to hold the assembly together. The first body part houses an actuating member such as a linear-acting solenoid having an armature terminating in a blocker. The first and second body parts retain a keeper subassembly comprising a flanged keeper, an axle, and a bias spring. The keeper protrudes through an opening in the second body part, and the axle is captured in journals preferably formed between the first and second body parts by assembly thereof. The spring is biased by assembly of the first and second body parts to cause the keeper to be returned to a locked position. The keeper includes a tang extending into the first body part and engaged by the blocker when the actuating member is in a first position, thus preventing rotation of the keeper in locked mode. When the actuating member is in a second position, as in unlocked mode, the blocker is withdrawn from such engagement, permitting rotation of the keeper. The body parts and keeper may be net formed by casting or other similar inexpensive manufacturing process and thus require no or little finish machining.
In a presently preferred further embodiment, the strike door keeper assembly includes an improved faceplate having a flange extending orthogonally from the plane of the faceplate to eliminate a torque-related shortcoming of prior art strike door keeper assemblies.
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate presently preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring to
In assembly of the electric strike door keeper, solenoid 18 is placed into cradle 24 and secured by clip 26. keeper subassembly 16 is then positioned adjacent solenoid 18 with axle 32 resting in lower half-journals 42,44 formed in the upper edge of lower body 12. First spring tang 36 is received in a channel 46 formed in lower body 12, and second spring tang 38 is received in a channel 48 formed within hub 28 such that rotation of keeper subassembly 16 during unlocking acts to store a restoring torque in spring 34. Upper body 14 is placed over keeper subassembly 16, with keeper flange 40 extending through a suitably shaped opening 50 and axle 32 is captured by upper body half-journals 43 (only one is visible in
Note that each of lower body 12 and upper body 14 has a plurality of mating surfaces facing in mutually orthogonal (x,y,z) directions; for example, lower body 12 includes mating faces 52,54,56, and upper body 14 includes mating faces 58,62.
Further, lower body 12 is provided with a channel 53 defining an ear 55 (
Note further that at completion of assembly, blocker 22 within cradle 24 is longitudinally adjacent a locking tang 66 extending from hub region 28, thus preventing rotation of keeper subassembly 16. In this configuration, with solenoid 18 de-energized, electric strike door keeper assembly 10 is in locked mode. When solenoid 18 is energized, armature 20 and blocker 22 are withdrawn axially from rotational interference with locking tang 66, permitting rotation of keeper subassembly 16 in unlocked mode. Thus, keeper subassembly 16 is unlatched and latched directly via the action of solenoid 18 and its integral blocker 22.
Unlike prior art electric strikes, no other components such as additional springs, pivots, levers, and the like are required, and the lower body 12, upper body 14, keeper subassembly 16, and blocker 22 may all be net formed without further or with little finishing such as precision grinding, thus greatly simplifying the assembly of an electric strike, reducing its cost, and improving its reliability.
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In operation, beginning with door 406 open, as door 406 closes in direction 410, the tapered or curved face 412 of latch bolt 414 passes through striker lip 209 and engages the outer end 416 of keeper flange 40. Continued closing force on door 406 causes latch bolt 414 to be forced into door 406 in direction 418 until the tip of latch bolt 414 clears end 416 of keeper flange 40. A spring (not shown) in assembly 404 causes latch bolt 414 to return in reciprocal direction 420 until latch bolt 414 is resident behind keeper flange 140. In this locked position, releasable security latch assembly 400 cannot be opened without either electrical release of electric strike door keeper assembly 10 or destruction of one or more components of assembly 400 or the door or frame.
To release security latch assembly 400, solenoid 18 is energized, causing armature 20 and blocker 22 to be withdrawn from rotational interference with locking tang 66 (FIGS. 1,2) as described above. In response to a door-opening force 320 (
While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.
