Door strike having a dead latch release

Abstract

An actuator-controlled strike comprising a housing disposable within a doorframe and including a cavity for a spring latch and a dead latch of a mortise-type lockset. A keeper is pivotably mounted within the chamber to engage the spring latch. A pivotably mounted kicker cooperates with the keeper. A pivotably mounted dead latch release is supported by the keeper when the spring latch is within the strike. The keeper is released by the actuator and rotates into a position to ramp the spring latch out of the strike, also allowing the dead latch release to release the dead latch into the cavity, allowing the spring latch to be ramped out of the strike. Pivoting the keeper causes the kicker to urge the spring latch onto an exit ramp on a face of the keeper. The dead latch release can be installed in a plurality of different locations in the housing.

Claims

1. An electric strike assembly, comprising: a) a housing formed with a cavity therein; b) a keeper pivotably mounted in said cavity of said housing, wherein said keeper includes a first tooth and a second tooth; c) a dead latch release platform pivotably mounted in said cavity of said housing and configured to rotate independently of a rotation of said keeper; and d) an actuator including an inhibitor, wherein said inhibitor includes a first tooth, a second tooth, and a third tooth, wherein a first recess is defined between said first tooth and said second tooth, wherein a second recess is defined between said second tooth and said third tooth, and wherein said inhibitor is selectively positionable in a fail-secure mode and a fail-safe mode, e) wherein when said inhibitor is in said fail-secure mode: said actuator is configured to move said inhibitor between a first position and a second position, wherein only said first and second teeth of said inhibitor are configured to directly engage said first and second teeth of said keeper, respectively, when said inhibitor is in said first position and said actuator is de-energized, and wherein said first and second recesses are aligned with said first and second teeth of said keeper, respectively, when said actuator is energized and said inhibitor is moved to said second position, and f) wherein when said inhibitor is in said fail-safe mode: said actuator is configured to move said inhibitor between said second position and a third position, wherein said first and second recesses are aligned with said first and second teeth of said keeper, respectively, when said inhibitor is in said second position and said actuator is de-energized, and wherein only said second and third teeth of said inhibitor are configured to directly engage said first and second teeth of said keeper, respectively, when said actuator is energized and said inhibitor is moved to said third position.

2. An electric strike assembly in accordance with claim 1 further comprising a compression spring disposed between said actuator and said inhibitor.

3. An electric strike assembly in accordance with claim 1 wherein said actuator is a solenoid.

4. An electric strike assembly in accordance with claim 3 wherein said solenoid is a linearly-acting solenoid.

5. A method of releasing a spring latch from an electric strike assembly, the method comprising: a) mounting said electric strike assembly in an associated door jamb, said electric strike assembly comprising: a housing formed with a cavity therein; a keeper pivotably mounted in said cavity of said housing, wherein said keeper includes a first tooth and a second tooth; a dead latch release platform pivotably mounted in said cavity of said housing and configured to rotate independently of a rotation of said keeper; and an actuator including an inhibitor, wherein said inhibitor includes a first tooth, a second tooth, and a third tooth, wherein a first recess is defined between said first tooth and said second tooth, wherein a second recess is defined between said second tooth and said third tooth, and wherein said inhibitor is selectively positionable in a fail-secure mode and a fail-safe mode; and b) wherein when said inhibitor is in said fail-secure mode said inhibitor is in a first position and a second position, wherein said inhibitor is in said first position so that only said first and second teeth of said inhibitor are in interfering relationship with said first and second teeth of said keeper when said actuator is de-energized, and wherein when said actuator is energized said inhibitor is moved to said second position so that said first and second teeth of said keeper are aligned with said first and second recesses; and c) wherein when said inhibitor is in said fail-safe mode said inhibitor is in said second position and a third position, wherein said inhibitor is in said second position so that said first and second teeth of said keeper are aligned with said first and second recesses when said actuator is de-energized, wherein when said actuator is energized said inhibitor is moved to said third position so that only said second and third teeth of said inhibitor are in interfering relationship with said first and second teeth of said keeper.

6. A method in accordance with claim 5 wherein said electric strike assembly further comprises a compression spring disposed between said actuator and said inhibitor.

7. A method in accordance with claim 5 wherein said actuator is a solenoid.

8. A method in accordance with claim 7 wherein said solenoid is a linearly-acting solenoid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

(2) FIG. 1 is a side elevational view of a door in a secure condition at a first door position within a door frame and having a portion of the door frame broken away to show an electrically-controlled strike in accordance with the present invention and operable with a mortise-type dead latch assembly of the door;

(3) FIG. 2 is an isometric view of a prior art mortise lockset for use with an electrically-controlled strike in accordance with the present invention;

(4) FIG. 3 is a perspective view of a strike plate according to the prior art for use with a mortise-type dead latch assembly such as that shown in FIG. 2 which would be replaced by an electrically-controlled strike in accordance with the present invention;

(5) FIG. 4A is an exploded perspective view of a complete electrically-controlled strike in accordance with the present invention;

(6) FIG. 4B is a perspective view of an electrically-controlled strike in accordance with the present invention;

(7) FIG. 5 is a cross-sectional view showing a door having a mortise lockset latched in a frame having an electrically-controlled strike in accordance with the present invention, the strike being in secured mode;

(8) FIG. 6 is a cross-sectional view sequential to the view shown in FIG. 5, showing the strike in an early stage of unlocking the spring latch and dead latch of the mortise lockset;

(9) FIG. 7 is a cross-sectional view sequential to the view shown in FIG. 6, showing the strike in a later stage of unlocking the spring latch and dead latch of the mortise lockset;

(10) FIG. 8 is a cross-sectional view sequential to the view shown in FIG. 7, showing the strike in a late stage of unlocking the spring latch and dead latch of the mortise lockset;

(11) FIG. 9A is a perspective view of a first embodiment of dead latch release subassembly for use in an electrically-controlled strike in accordance with the present invention;

(12) FIG. 9B is a perspective view of a second embodiment of dead latch release subassembly for use in an electrically-controlled strike in accordance with the present invention;

(13) FIG. 10 is a plan view showing five different configurations for installation of the dead latch release subassembly, corresponding to five different mortise lockset arrangements of dead latch and spring latch;

(14) FIG. 11A is a perspective view of a solenoid actuation mechanism in accordance with the present invention, showing the strike in locked mode with a keeper engaged with first and second teeth of an inhibitor;

(15) FIG. 11B is a perspective view of a solenoid actuation mechanism in accordance with the present invention, showing the strike in unlocked mode; and

(16) FIG. 11C is a perspective view of a solenoid actuation mechanism in accordance with the present invention, showing the strike in locked mode with the keeper engaged with second and third teeth of the inhibitor.

(17) Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrates currently preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(18) The present invention is broadly directed to an automated door latch release system that is adapted to be installed in a door jam or frame so that it can operate with a mortise-type lock with dead latch assembly such as those found in typical commercial and industrial applications. The present invention also encompasses a method for automated door release. The present invention is particularly adapted for use with security doors in industrial and commercial applications wherein the security system can be electronically activated to release the door so that it may be moved from a secured first door position wherein it is secured within the door jam to an open position. The automated door lock release, also referred to herein as an electrically-controlled strike, is primarily adapted for use with a mortise-type dead latch assembly mounted in the door. Here, the mortise-type dead latch assembly includes a spring latch and a dead latch that are spaced-apart from one another along the edge of the door. Moreover, the present invention is specifically adapted to be mounted in the dimensions of a typical door jam, requiring no further modifications, other than the location of the dead latch platform, to interface with a variety of different styles of mortise-type dead locks.

(19) An automated door lock release or strike in accordance with the present invention is an improvement over the prior art automated door latch release disclosed in U.S. Pat. No. 6,581,991 B2 and is intended to function as a direct replacement thereof. Referring to FIG. 1, an embodiment of the invention disclosed in U.S. Pat. No. 6,581,991 B2 is in the form of a prior art automated door latch actuator 10 that is received in a cavity 12 in a typical door jam 14. Actuator 10 includes an outer housing 16 which mounts its electrical and mechanical components. The electrical components in turn are electrically in communication by means of wiring 20. Actuator 10, for example, may be electrically in communication with a source 17 of electrical power such as for example, a 12 or 24 volt circuit, and with a trigger device 22. Activation of the trigger device will cause the door latch actuator to activate. The trigger device 22 may typically be a switch whose contacts selectively actuate the door latch actuator. The trigger device 22, however, is often incorporated into a control entry device such as a card reader or digital entry keypad. Here, an authorized card is presented or an authorized code is entered into trigger device 22.

(20) A typical door 24 is shown in FIG. 1 in a first or closed position. Again, for example purposes, door 24 may be pivotally mounted so that it can move between a closed position and an open position.

(21) Door latch actuator 10 is constructed to interface with a mortise-type lockset assembly 30 according to the prior art, exemplarily shown in FIG. 2. A prior art mortise-type lockset assembly 30 includes a spring latch 32 and a dead latch 34. Spring latch 32 and dead latch 34, when mounted in a door, are linearly spaced-apart from one another along the edge portion of the door. Both spring latch 32 and dead latch 34 are spring-biased to extend outwardly from lockset assembly 30. Thus, as one of ordinary skill in the art can appreciate, spring latch 32 is slideably moveable between an advanced or engaged position, wherein the spring latch 32 is fully extended from the edge portion of the door such that it can engage the latch bolt receiving cavity 46 (FIG. 3), and a retracted or release position wherein spring latch 32 is retracted into the door and becomes disengaged from the latch bolt receiving cavity 46, allowing the door to open.

(22) Dead latch 34 similarly is reciprocally moveable between an extended or enabling position and a depressed or disabling position. As is known in the prior art, when the dead latch is held in its disabling position, it prevents (disables) movement of the spring latch bolt from moving from the engaged position to the release position. However, when the dead latch extends into the enabling position, the spring latch bolt may reciprocate between the engaged position and the release position. In FIG. 2, dead latch 34 is shown in the extended or enabling position and spring latch 32 is shown in the engaged position. Spring latch 32 is free to be urged into lockset assembly 30 in response to an opening force on door 24 as by a user rotating the door handle 29.

(23) With reference now to FIG. 3, a prior art strike plate 36 for use with mortise-type locksets of the prior art, such as lockset assembly 30, includes a rectangular central body portion 38 having oppositely projecting mounting tabs 40 provided with holes 42 adapted to receive screws for mounting on door jam 14. A lateral flange 44 projects away from central body portion 38 in a slightly curved configuration so as to interact with the curved edges of spring latch 32 and dead latch 34 when the door swings shut. A latch bolt receiving cavity 46, in the form of an opening, is provided in central body 38 of strike plate 36 so that, when the door closes, spring latch 32 extends into receiving cavity 46 to hold the door in the closed position. Dead latch 34, on the other hand, bears against the surface of strike plate 36 in the region designated 48 and is held in the depressed or disabling position thereby to lock the door. However, and with reference to FIG. 2, mortise-type lockset assembly 30 typically includes a key lock 35 that includes a mechanism to selectively retain spring latch 32 in the engaged position or to release spring latch 32 so that it may move between the engaged position and the release position. This construction is believed to be well-known to those skilled in the art and is not part of the present invention.

(24) Referring now to FIGS. 4A through 11, an improved electrically-controlled strike 110 in accordance with the present invention comprises a housing 116 including a rectangular central body portion 138 having oppositely projecting mounting tabs 140 provided with holes 142 for receiving screws 143. As best seen in FIG. 4A, housing 116 includes a longitudinal length (LL), a width (W), and a depth (D). An improved strike plate 136 having a central cutout portion 150 is adapted to fit over housing 116 to secure housing 116 via screws 143 into a cavity in a door jamb 14 as described above for prior art door latch actuator 10 (FIG. 1). Housing 116 is provided along an edge with a lateral flange 144 preferably running substantially the full longitudinal length LL of housing 116 that serves as an entry and exit ramp for a spring latch and dead latch as described below.

(25) A dead latch release subassembly 152 (best shown in FIG. 9A) comprises a dead latch release platform 154 pivotably disposed in a platform mount 156. A compression spring 158 is disposed between platform 154 and mount 156 to resiliently urge subassembly 152 into the configuration shown in FIGS. 5 and 8. Platform mount 156 is provided with a pair of hooks 160 and a gib 162. Hooks 160 engage notches 163 (FIG. 4A) in a wall of housing 116 and gib 162 engages a supportive bench 161 (FIG. 5).

(26) A first embodiment of the dead latch release subassembly 152 (FIG. 9A) includes a nose tang 164. A second embodiment of the dead latch release subassembly 152 (FIG. 9B) includes a roller 164 disposed in a fork 165, replacing tang 164.

(27) A keeper 166 is pivotably mounted longitudinally of housing 116 and in the locked position (FIG. 5) engages nose tang 164 (or roller 164, not shown in FIG. 5) to support dead latch release platform 154 or 154. Thus, when door lockset assembly 30 (FIG. 2) is in the locked mode, dead latch 34 is held in a depressed position in assembly 30 by release platform 154. Surface 169 of keeper 166 further engages lockset spring latch 32 along surface 168 and door opening force 178 is directed substantially perpendicular to surface 169, thus preventing door 24 from being opened. A return spring 167 disposed between keeper 166 and housing 116 urges keeper 166 toward the locked position shown in FIG. 5.

(28) A kicker 170 is also pivotably mounted longitudinally of housing 116 and rests against a leg 172 of keeper 166. A return spring 173 is mounted on kicker 170 and constrained by body 116. Return spring 173 may be but is not limited to, a leaf, compression or torsion spring. As described in detail below, a solenoid is linearly operative against keeper 166 to selectively permit rotation of the keeper as described below when an unlocked mode for mechanism 110 is desired.

(29) Referring to FIGS. 6 through 8, in operation of strike 110 the unlocking sequence is shown.

(30) In FIG. 6, as keeper 166 begins to rotate counterclockwise in response to opening force 178 on door 24, nose tang 164 or roller 164 is no longer supported by keeper 166. Because spring 158 in subassembly 152 is deliberately provided to be weaker than the dead latch spring in mortise lockset 30, dead latch release platform 154 is caused by dead latch 34 to pivot in platform mount 156, allowing the dead latch to extend from door 24 into its extended, enabling position. Spring latch 32 is now free to be urged into lockset 30.

(31) In FIG. 7, as keeper 166 continues to rotate counterclockwise, leg 172 urges kicker 170 to rotate correspondingly in a clockwise direction. Kicker 170 is so named because it literally kicks spring latch 32 out of locked engagement with keeper 166. When the nose 174 of spring latch 32 reaches the inclined surface 176 of keeper 166 (FIG. 7) by the action of kicker 170, opening force 178 on door 24 serves to cause nose 174 to slide along inclined surface 176 as spring latch 32 is further forced into lockset 30 until nose 174 reaches lateral flange 144 (FIG. 8) and door 24 is freed from engagement with strike 110.

(32) Referring to FIG. 10, dead latch release subassembly 152 may be positioned in notch 163 (FIG. 4A) at any one of a plurality of positions, allowing strike 110 to be used with any of a plurality of mortise locksets having differing position arrangements of their dead latches and spring latches. In the example shown herein, strike 110 may accommodate five positions 110A through 110E of subassembly 152 corresponding to five sets of notches 163 in housing 116 (FIG. 4A). Moreover, because of the flexibility of strike 110 to accommodate various positions of the dead latch relative to the spring latch, strike 110 in accordance with the invention may be used, of equal utility, in either a right-hand-hinge or left-hand-hinge door frame.

(33) Referring to FIG. 11A, actuator 180, in the form of a linear-acting solenoid, is disposed in a cavity 181 in housing 116 and includes a plunger formed as an inhibitor 182. Inhibitor 182 includes a first tooth 190, a second tooth 192, and a third tooth 194, wherein a first recess 196 is defined between first and second teeth 190, 192, and wherein a second recess 198 is defined between second and third teeth 192, 194. A compression spring 184 disposed between actuator 180 and inhibitor 182 urges first and second teeth 190, 192 of inhibitor 182 into an interfering relationship with first and second mating teeth 186a, 186b on keeper 166 to prevent rotation of keeper 166, thereby locking spring latch 32 into strike 110 (FIG. 5) when actuator 180 is de-energized. Referring to FIG. 11B, when actuator 180 is energized, inhibitor 182 is moved in direction 188 to move first and second teeth 190, 192 of inhibitor 182 into a non-interfering relationship with first and second mating teeth 186a, 186b of keeper 166 to permit rotation of keeper 166 to release spring latch 32 from strike 110. Thus, the strike is in a fail secure mode meaning that, when solenoid 180 is not energized, the door is prevented from disengaging strike 110.

(34) It should be noted that, by re-aligning inhibitor 182 relative to first and second mating teeth 186a, 186b on keeper 166 as shown in FIG. 11B, when actuator 180 is not energized, second and third teeth 192, 194 of inhibitor 182 can be moved into an interfering relationship with first and second mating teeth 186a, 186b of keeper 166 when actuator 180 is energized. By re-aligning inhibitor 182 in this manner, the strike can be transformed to operate in a fail safe mode (that is, when the solenoid is not energized, the door is permitted to disengage the strike).

(35) 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.