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| United States Patent | 5474342 |
| Link to this page | http://www.wikipatents.com/5474342.html |
| Inventor(s) | Smith; Jerry R. (5690 W. Rowland Ave., Littleton, CO 80123);
Hick; John N. (1093 Geneva St., Aurora, CO 80010) |
| Abstract | A door latch actuator is adapted for use in association with a bolt
receiver which is to be engaged by a latch bolt of latch bolt assembly on
a door mounted for movement between a first door position and a second
door position. The latch bolt assembly includes a latch bolt having a
distal end which slideably moves between an extended state and a retracted
state. In the extended state, the latch bolt assembly is operative to
engage a bolt receiver to retain the door at the first door position in a
secured condition. Broadly, the door latch actuator comprises an actuator
element and a driver. The actuator element is disposed in proximity to the
distal end of the latch bolt when the door is at the first door position
in the secured condition and moves between a first actuator position and a
second actuator position. In the first actuator position, the actuator
element allows the distal end of the spring latch bolt to engage a bolt
receiver in the extended state. When moved into the second actuator
position, the actuator element displaces the spring latch bolt from the
extended state to the retracted state causing the door to be in an
unsecured condition at the first door position so that the door can be
moved from the first door position to the second door position. |
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Title Information  |
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Drawing from US Patent 5474342 |
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Door latch actuator |
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| Publication Date |
December 12, 1995 |
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| Filing Date |
August 4, 1993 |
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Title Information  |
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Claims  |
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I claim:
1. A door latch actuator adapted for use in association with a bolt
receiver which is to be engaged by a latch bolt of a latch bolt assembly
on a door that is mounted for movement between a first door position and a
second door position, wherein said latch bolt has a distal end which
slideably moves between an extended state and a retracted state and is
operative in the extended state to engage the bolt receiver to retain the
door at the first door position in a secured condition, said door latch
actuator comprising:
(a) an actuator element disposed in proximity to the distal end of the
latch bolt when the door is at the first door position in the secured
condition, said actuator element including a cam having a first cam
surface and movable between a first actuator position wherein said first
cam surface operates to contact the distal end of the latch bolt and
allows the distal end of the latch bolt to engage the bolt receiver in the
extended state and a second actuator position wherein said actuator
element displaces said latch bolt from the extended state to the retracted
state causing the door to be in an unsecured condition at the first door
position so that the door can be moved from the first door position to the
second door position; and
(b) a driver associated with said actuator element and operative to provide
a reversible driving force which acts to reciprocally pivot said cam
between the first and second actuator positions.
2. A door latch actuator according to claim 1 wherein said driver includes
an electric motor and a gear assembly operably connected to and between
said electric motor and said cam.
3. A door latch actuator according to claim 1 including a controller device
operative to reversibly activate said driver whereby said cam is caused to
pivot between the first and second actuator positions.
4. A door latch actuator according to claim 3 wherein said controller
device includes timer circuitry operative after said cam moves from the
first actuator position to the second actuator position to cause said cam
to return to the first actuator position upon expiration of a selected
period of time.
5. A door latch actuator mounted in a latch bolt receiving cavity in a
doorjamb and operative with a latch bolt assembly on a door that is
pivotally mounted in a door frame for movement between a first door
position and a second door position wherein the latch bolt assembly
includes a spring latch bolt and a dead latch bolt which have distal ends
respectively being spring biased to extend into the latch bolt receiving
cavity when the door is in the first door position, said spring latch bolt
being slideably movable between an extended state and a retracted state
and said dead latch bolt being slideably movable between an enable state
which permits the spring latch bolt to move from the extended state to the
retracted state and a disable state which prohibits the spring latch bolt
from moving from the extended state to the retracted state, said door
latch actuator comprising:
(a) an actuator element disposed in proximity to the distal ends of both
said spring latch bolt and said dead latch bolt when the door is in the
first position and movable between a first and second actuator position,
said actuator element when in the first actuator position operative to
retain said dead latch bolt in the disable state while allowing said
spring latch bolt to extend into the latch bolt receiving cavity in the
extended state thereby to retain the door at the first door position in a
secured condition, said actuator element operative upon movement from the
first actuator position to the second actuator position to first allow
said dead latch bolt to move into the enable state and then attack the
distal end of said spring latch bolt to move said spring latch bolt from
the extended state to the retracted state thereby causing the door to be
in an unsecured condition at the first door position so that the door can
be moved from the first door position to the second door position; and
(b) a driver associated with said actuator element and operative to move
said actuator element between said first and second actuator positions.
6. A door latch actuator according to claim 5 wherein said actuator element
includes a first actuator cam portion and a second actuator cam portion
connected to said first actuator cam portion, said first actuator cam
portion having a first cam surface operative to contact the distal end of
said dead latch bolt when said actuator element is in the first actuator
position and said second actuator cam portion having a second cam surface
operative to contact said distal end of said spring latch bolt when said
actuator element is in the second actuator position.
7. A door latch actuator according to claim 5 wherein said driver causes
said actuator element to pivot about an axis.
8. A door latch actuator according to claim 7 wherein said driver includes
an electric motor and a gear assembly operably connected to and between
said electric motor and said actuator element.
9. A door latch actuator according to claim 5 including a controller device
operative to reversibly activate said driver whereby said actuator element
reciprocately pivots between the first and second actuator positions.
10. A door latch actuator according to claim 9 wherein said controller
device includes timer circuitry operative after said actuator element
pivots from the first actuator position to the second actuator position to
cause said actuator element to return to the first actuator position upon
expiration of a selected period of time.
11. A door latch actuator according to claim 5 including a strike plate
adapted to connect to said driver and to releasably attach to the doorjamb
and over the latch bolt receiving cavity, said strike plate having a port
adapted for the spring latch bolt and the dead latch bolt to extend
therethrough and into the latch bolt receiving cavity in the doorjamb.
12. A door latch actuator according to claim 11 including a support element
adapted to attach to said strike plate and to pivotally receive said
actuator element.
13. A door latch actuator according to claim 12 wherein said support
element includes a stop portion adapted to restrict movement of said
actuator element between the first and second actuator positions.
14. A door latch actuator according to claim 11 including a support bracket
attached to said strike plate and adapted to secure said driver to said
strike plate.
15. A door latch actuator mounted within a latch bolt receiving cavity in a
doorjamb and operative with a latch bolt assembly on a door that is
pivotally mounted in a door frame for moving the door between a first door
position and a second door position wherein the latch bolt assembly
includes a spring latch bolt and a dead latch bolt, both the spring latch
bolt and dead latch bolt being spring biased to extend from the door and
into the latch bolt receiving cavity when the door is at the first
position, the spring latch bolt being slideably movable between an
extended state and a retracted state and said dead latch bolt being
slideably movable between an enable state which permits the spring latch
bolt to move from the extended state to the retracted state and a disable
state which prohibits the spring latch bolt from moving from the extended
state to the retracted state, said door latch actuator comprising:
(a) a strike plate being adapted to releasably attach to the doorjamb and
having a port adapted for the spring latch bolt and the dead latch bolt to
extend therethrough and into the latch bolt receiving cavity in the
doorjamb:
(b) an actuator element disposed in proximity to the distal ends of both
said spring latch bolt and said door latch bolt and movable between first
and second actuator positions, said actuator element when in the first
actuator position operative to retain said dead latch bolt in the disable
state while allowing said spring latch bolt to extend into the latch bolt
receiving cavity in the extended state thereby to retain the door at the
first door position in a secured condition, said actuator element
operative upon movement from the first actuator position to the second
actuator position to first allow said dead latch bolt to move into the
enable state and then attack the distal end of said spring latch bolt to
move said spring latch bolt from the extended state to the retracted state
thereby causing the door to be in an unsecured condition at the first door
position so that the door can be moved from the first door position to the
second door position; and
(c) a driver adapted to connect to said strike plate and operative to move
said actuator element between the first and second actuator positions.
16. A door latch actuator according to claim 15 wherein said strike plate
includes a pair of support prongs and a link plate, said support prongs
adapted to pivotally receive said actuator element, said link plate
adapted to provide a vertical surface.
17. A door latch actuator according to claim 16 wherein said actuator
element is adapted to pivot between said pair of support prongs and
includes an actuator cam portion pivotally connected to a sliding link
wherein, upon movement from the first actuator position to the second
actuator position, said sliding link operative to slide along said
vertical surface to first allow said dead latch bolt to move from the
disable state to the enable state so that said actuator cam portion can
attack the distal end of said spring latch bolt to move said spring latch
bolt from the extended state to the retracted state.
18. A door latch actuator according to claim 17 wherein said actuator
element includes a spring operative to bias said sliding link against said
vertical surface.
19. A door latch actuator according to claim 15 wherein said driver and
said actuator element are provided by a pair of solenoids.
20. A door latch actuator according to claim 15 wherein said driver and
said actuator element are provided by a motor operative to drive a cam and
a solenoid.
21. A door latch actuator according to claim 15 wherein said actuator
element is formed by a pair of separate actuator cam elements. |
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Claims  |
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Description  |
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FIELD OF THE INVENTION
This invention generally relates to security devices for doors to control
access by personnel into buildings or restricted areas therein. More
particularly, this invention relates to a door latch actuator which works
in cooperation with a standard latch bolt assembly of a door. This
invention is specifically suitable to retro-fit on existing doors and can
be used in conjunction with electronic door security systems which afford
access to those who employ a valid card key device or an authorized code.
BACKGROUND OF THE INVENTION
Providing security for a door has been a concern over centuries. The
earliest known mechanical lock for a door can be traced back to early
Egyptian times over 4,000 years ago. The early Egyptians employed a
sliding wooden bolt through a stationary staple. The staple contained
vertically positioned pin tumblers which extended into corresponding holes
in the bolt when locked. The key was a curved, flattened wooden stick with
pins projecting from one end. This end of the key was inserted into a
hollowed portion of the bolt and maneuvered upwardly to push the pins from
the bolt. The bolt then could be withdrawn to unlatch the door.
By the 13th Century, a metal warded lock which was first developed by the
Romans, became very popular throughout Europe. This type of lock required
that a key must be made to bypass the wards of the lock. Once bypassed,
the key could then be turned to operate the latch. During the 18th
Century, the tumbler lock was invented. Similar to the principal of the
early Egyptian lock, the tumbler could be raised an exact height to clear
its slot. This lock remains as the basis for modern locks today with the
only difference being the use of multiple tumblers. Although lock and keys
are still an effective way of controlling access to a building structure
or a restricted area therein, the issuance of a key or a set of keys to
numerous personnel has become impractical.
In general, modern door locks are used in conjunction with a conventional
latch bolt assembly which is installed on a standard door. The latch bolt
assembly includes a spring latch bolt and often includes a dead latch bolt
that enables and disables movement of the spring latch bolt. The spring
latch bolt is spring biased to extend from the door and into a latch bolt
receiving cavity in the doorjamb when the door is in a closed position.
The dead latch both is spring-biased outwardly from the latch assembly,
but, when the door is secured, the dead latch bolt is depressed to disable
retraction of the spring latch bolt. The spring latch bolt is slideably
movable between an extended state and a retracted state and the dead latch
bolt is slideably movable between an enable state and a disable state. In
the enable state, the dead latch bolt permits the spring latch bolt to
move from the extended state to the retracted state. In the disable state,
the dead latch bolt prohibits the spring latch bolt from moving from the
extended state to the retracted state. Typically, a strike plate is used
to retain the dead latch bolt in its disable state unless a computerized
security system is employed.
When security is required to control access through a door, especially one
that is provided with the standard latch assembly described above, it is
known to employ a computerized security system. Here, anyone with a valid
key card or an authorized access code can gain access through secured
doors. With the advent of computers, each person can have his/her own key
card or access code so that a person may be authorized to gain access
through one, all or a specified number of doors. If, for example, the key
card is lost or stolen, that particular key card could be canceled and a
new key card with a new access code could be issued.
In a computerized system, an electronic strike is activated when the
appropriate access code is detected so that the person having a valid key
card may enter through the door. In general, this electronic strike
includes a single-lobed cam that pivots between a door lock position and a
door release position. In its door lock position, the cam is positioned to
simultaneously capture the spring latch bolt and the dead latch bolt with
the spring latch bolt projecting into its extended state and and with the
dead latch bolt retained in its disable state. In the door lock position,
a pin from an electrically-powered solenoid extends into a recess in the
cam to prevent movement of the cam from pivoting out of its door lock
position. When the correct access code is detected, the pin from the
solenoid withdraws from the recess in the cam so that the cam is free to
pivot away from the latch as the door is pulled open. After the latch bolt
assembly clears the cam, it springs back into its original position and,
after a few seconds, the pin of the solenoid once again is extended into
the recess of the cam to retain the door in its closed position.
A problem associated with this solenoid-type electric strike is that, if a
user is pulling on the door at that time when the computer sends the
electric signal to release the strike, the strike might not release.
Pulling on a door results in pulling on the extended latch. The extended
latch, in turn, applies back pressure against the cam being held by the
solenoid pin in the door lock position. Now, the solenoid pin is unable to
be withdrawn from its recess due to this back pressure. Thus, the pin
cannot release thereby preventing the door from being opened.
Furthermore, installation of such a strike device for an existing,
unsecured door requires substantial modifications to the doorjamb. Not
only must the side portion of the doorjamb be modified but also the front
portion of the doorjamb must be modified. This results in the electric
strike being exposed so that now an intruder may use a lever against the
cam to break the solenoid pin of the door latch actuator for easy entry
because there is no face plate or other protective mechanism to encase the
electric strike.
A need exists in the marketplace to provide a door latch actuator that is
easy to install into existing doorjambs without making major modifications
thereto. It would be beneficial if the door latch actuator is simple and
inexpensive to manufacture. There is also a need to provide a door latch
actuator that can provide a higher measure of security to prevent easy
breaking and entering as compared to existing electric strike devices. It
would be advantageous to provide a door latch actuator that can employ
conventional components such as the strike plate that is presently being
used on the doorjamb. The major benefit of using prior art components is
that non-secured doors can now be easily retro-fitted as secured doors.
Also, reducing installation time of the door latch actuator would be
beneficial. It is from these considerations and others that the present
invention has evolved.
SUMMARY OF THE PRESENT INVENTION
It is an object of the present invention to provide a new and useful door
latch actuator that is simple to manufacture and easy to install.
It is yet another object of the present invention to provide a door latch
actuator that is generally insensitive to back pressure applied to the
door so that the door can be opened even if back pressure is being applied
to the door.
It is yet a further object of the present invention to provide a door latch
actuator that provides a higher degree of security, compared to those of
the prior art, by employing a strike plate which is commonly used on door
jambs.
A still further object of the present invention is to provide a door latch
actuator whereby its installation time is brief and its installation cost
is inexpensive.
Another object of the present invention is to provide a door latch actuator
that can be easily retrofitted onto existing non-secured door systems to
provide security therefor without making major modifications to the
doorjamb.
Yet another object of the present invention is to provide a door latch
actuator that interacts with the standard dead latch bolt to depress the
dead latch bolt until actuation so that the security feature afforded by
the dead latch bolt is retained.
In general, the door latch actuator of the present invention is adapted for
use in association with a conventional latch bolt assembly on a
conventional door which is pivotally mounted on a door frame for movement
between a first door position and a second door position. The latch bolt
assembly includes a latch bolt having a distal end which slideably moves
between an extended state and a retracted state and is operative in the
extended state to engage a bolt receiver to retain the door at the first
door position in a secured condition. In its broadest form, the door latch
actuator comprises an actuator element which is disposed in proximity to
the distal end of the latch bolt when the door is at the first door
position in the secured condition and a driver which is associated with
the actuator element. The actuator element moves between a first actuator
position and a second actuator position. In the first actuator position,
the actuator element allows the distal end of the latch bolt to engage the
bolt receiver in the extended state. In the second actuator position, the
actuator element mechanically displaces the latch bolt from the extended
state to retracted state causing the door to be in an unsecured condition
at the first door position so that the door can then be moved from the
first door position to the second door position. The driver operates to
move the actuator element between the first and second actuator positions.
The actuator member preferably is a cam, and the driver acts to move the
cam between the first and second actuator positions. The cam provides a
first cam surface operative to contact the distal end of the latch bolt in
order to move the latch bolt from the extended state to the retracted
state when the driver moves the cam between the first and second actuator
positions. The driver operates to provide a reversible driving force to
the cam and acts to reciprocally pivot the cam between the first and
second actuator positions. It is preferred that the driver includes an
electric motor and a gear assembly operably connected to and between the
electric motor and the cam. It is also preferred that the door latch
actuator include a controller device operative to reversibly activate the
driver so that the cam is caused to pivot between the first and second
actuator positions. Also, timer circuitry may be included with the
controller to operate after the cam pivots from the first actuator
position to the second actuator position to cause the cam to return the
first actuator position upon expiration of a selected period of time.
Where the conventional latch bolt assembly in the door includes a spring
latch bolt and dead latch bolt, an alternative door latch actuator can be
employed according to the present invention. Here, the latch bolt assembly
is mounted on a door that is pivotally mounted in a door frame for
movement between a first door position and a second door position. The
alternative door latch actuator is then mounted a latch bolt receiving
cavity in a doorjamb. Generally, the door latch actuator comprises an
actuator element disposed in proximity to distal ends of the spring latch
bolt and the dead latch bolt and a driver which is associated with the
actuator element. The actuator element moves between a first actuator
position and a second actuator position. In the first actuator position,
the actuator element is operative to retain the dead latch bolt in the
disable state while allowing the spring latch bolt to extend into the
latch bolt receiving cavity in the extended state to retain the door at
the first door position in a secured condition. The actuator element,
operative upon movement from the first actuator position to the second
actuator position, first releases the dead latch bolt so that it moves
into the enable state, the actuator element next attacks the distal end of
the spring latch bolt to move the spring latch bolt from the extended
state to the retracted state. Now, the door can be moved from the first
door position to the second door position. The driver operates to move the
actuator element between the first and second actuator positions by
causing the actuator element to pivot about an axis.
The actuator element includes a first actuator cam portion and a second
actuator cam portion connected to the first actuator cam portion. The
first actuator cam portion has a first cam surface which operates to
contact the distal end of the dead latch bolt when the actuator is in the
first actuator position. The second actuator cam portion has a second cam
surface which operates to contact the distal end of the spring latch bolt
when the actuator is in the second actuator position.
The driver includes an electric motor and a gear assembly. The gear
assembly is operatively connected to and between the electric motor and
the actuator element. It is preferable that the door latch actuator
include a controller device which operates to reversibly activate the
driver so that the actuator element reciprocates between the first and
second actuator positions. Furthermore, the controller device preferably
includes timer circuitry which would operate after the actuator element
pivots from the first actuator position to the second actuator position to
cause the actuator element to return to the first actuator position upon
expiration of selected period of time. The door latch actuator also
includes a strike plate which is adapted to connect to the driver and to
releasably attach to the doorjamb and over the latch bolt receiving
cavity. The strike plate has a port adapted for the spring latch bolt and
the dead latch bolt to extend therethrough and into the latch bolt
receiving cavity in the doorjamb. Also, the door latch actuator includes a
support bracket which is attached to the strike plate and adapted to
secure the driver to the strike plate. A support element also attaches to
the strike plate and is adapted to pivotally receive the actuator element.
The support element preferably includes a stop portion which is adapted to
restrict movement of the actuator element between the first and second
actuator positions.
Another alternative embodiment of the present invention can be fabricated
by modifying the strike plate and the actuator element. The strike plate
would include a pair of support prongs and a link plate. The support
prongs are adapted to pivotally receive the actuator element. The actuator
element would include an actuator cam portion pivotally connected to a
sliding link. Upon movement from the first actuator position to the second
actuator position, the sliding link, being operative to slide along the
vertical surface, first allows the dead latch bolt to move from the
disable state to the enable state so that the actuator cam portion can
then attack the distal end of the spring latch bolt to move it from the
extended state to the retracted state. A spring connected to the actuator
cam and the sliding link operates to bias the sliding link against the
vertical surface.
Other embodiments of the present invention include a pair of solenoids, a
pair of actuator pieces or a combination of a solenoid and an actuator
piece.
These and other objects of the present invention will become more readily
appreciated and understood from a consideration of the following detailed
description of the preferred exemplary embodiments when taken together
with the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of a door in a secured condition at a
first door position within a doorjamb and having a portion of the doorjamb
broken away to show a door latch actuator according to a first preferred
exemplary embodiment of the present invention and operable with a
conventional latch bolt assembly of a door and a conventional electronic
trigger element;
FIG. 2 is an exploded perspective view of the door latch actuator shown in
FIG. 1;
FIG. 3 is a perspective view of the distal ends of a spring latch bolt and
a dead latch bolt which extend from a conventional latch bolt assembly
installed in a conventional door;
FIG. 4 is an enlarged side elevational view of the door latch actuator of
FIGS. 1 and 2 and operable with the conventional latch bolt assembly shown
in FIG. 3;
FIG. 5(a) is a top plan view taken along lines 5--5 in FIG. 4 of an
actuator element of the present invention disposed in proximity to the
conventional latch bolt assembly wherein a spring latch bolt extends into
a latch bolt receiving cavity in the extended state and a dead latch bolt
is retained in the disable state within the latch bolt receiving cavity;
FIG. 5(b) is a top plan view taken along line 5--5 in FIG. 4 of the
actuator element of the present invention disposed in proximity to the
conventional latch bolt assembly wherein the spring latch bolt extends
into the latch bolt receiving cavity in the extended state and the dead
latch bolt is released to the enable state;
FIG. 5(c) is a top plan view taken along line 5--5 in FIG. 4 of the
actuator element of the present invention disposed in proximity to the
conventional latch bolt assembly wherein the spring latch bolt is retained
in the retracted state;
FIG. 6 is a perspective view of the distal end of a spring latch bolt
extending from a conventional latch bolt assembly but where no dead latch
bolt is employed;
FIG. 7(a) is a top plan view of the actuator element disposed in proximity
to the conventional latch bolt assembly of FIG. 6 wherein a spring latch
bolt extends into a latch bolt receiving cavity in the extended state;
FIG. 7(b) is a top plan view of the actuator element disposed in proximity
to the conventional latch bolt assembly of FIG. 6 wherein the spring latch
bolt is retained within the latch bolt receiving cavity in the retracted
state;
FIG. 8 is a perspective view of a second alternative exemplary embodiment
of a door latch actuator shown in FIG. 2;
FIG. 9(a) is a top plan view of an actuator element of FIG. 8 disposed in
proximity to the conventional latch bolt assembly wherein the spring latch
bolt extends into the latch bolt receiving cavity in the extended state
and the dead latch bolt is retained in the retained state within the latch
bolt receiving cavity by a sliding link;
FIG. 9(b) is a top planar view of the actuator element of FIG. 8 disposed
in proximity to the conventional latch bolt assembly wherein the sliding
link slides along a vertical surface to first allow the dead latch bolt to
move to the enable state and an actuator cam portion attacks the spring
latch bolt extending into the latch bolt receiving cavity;
FIG. 9(c) is a top plan view of the actuator element of FIG. 8 disposed in
proximity to the conventional latch bolt assembly wherein the actuator cam
portion retains the spring latch bolt in the retracted state within the
latch bolt receiving cavity;
FIG. 10 is a top plan view of a third alternative exemplary embodiment of
the door latch actuator of FIG. 2 which includes a pair of solenoids;
FIG. 11 is a top plan view of a fourth alternative exemplary embodiment of
the door latch actuator of FIG. 2 which includes an actuator cam portion
and a solenoid; and
FIG. 12 is a top plan view of a fifth alternative exemplary embodiment of
the door latch actuator of FIG. 2 which includes a pair of actuator cam
elements.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
A door latch actuator of the present invention is adapted to be installed
into a latch bolt receiving cavity formed in a doorjamb so that it can
operate with a conventional door latch assembly of a common door.
Typically, the door latch assembly includes a spring latch bolt and a dead
latch bolt. Generally, for interior doors, the door latch assembly might
include only the spring latch bolt. The door latch actuator of the present
invention operates with either type of door latch assembly and, in its
broadest form, includes an actuator element and a driver.
With reference to FIGS. 1 through 5, a first preferred exemplary embodiment
of a door latch actuator 10 of the present invention and its operation are
shown. In FIG. 1, a door latch actuator 10 is shown mounted in a latch
bolt receiving cavity 12 in a doorjamb 14. As best shown in FIG. 2, the
door latch actuator 10 comprises an actuator element 16 and a driver 18.
Here, actuator element 16 includes a first actuator cam portion 20 and a
second actuator cam portion 22 which is integrally formed with one another
in an L-shaped configuration. The driver 18 includes an electric motor 24
and a gear assembly 26 which is operably connected to and between the
electric motor 24 and the actuator element by a shaft (not shown) of the
electric motor 24 and acts to drive the actuator element 16. It is
preferable that the door latch actuator 10 be operatively mounted to and
supported by a strike plate 30. Accordingly, a support bracket 32 and a
support element 34 are attached to the strike plate 30. A support bracket
fastener 36 cooperates with the support bracket 32 in order to secure the
driver 18 onto the strike plate 30. A suitable electronic controller 28 is
provided to control operation of motor 24.
The door latch actuator 10 is mounted in a latch bolt receiving cavity in a
doorjamb and works in conjunction with a conventional latch bolt assembly
38 installed on a standard door 40 as shown in FIGS. 1, 3 and 4. The door
40 is pivotally mounted in a door frame 42 (FIG. 1) so that the door can
move between a first door position and a second door position. As best
shown in FIG. 3, the latch bolt assembly 38 includes a spring latch bolt
44 and a dead latch bolt 46. Both the spring latch bolt 44 and the dead
latch bolt 46 have distal ends respectively which are spring biased to
extend into the latch bolt receiving cavity 12 in the doorjamb 14 when the
door 40 is in the first door position as shown in FIGS. 1 and 4. As one of
ordinary skill in the art would appreciate, the spring latch bolt 44 is
slideably movable between an extended state and a retracted state and the
dead latch bolt 46 is slideably movable between an enable state and a
disable state. In the enable state, the dead latch bolt 46 permits the
spring latch bolt 44 to move from the extended state to the retracted
state. In the disable state, the dead latch bolt 46 prohibits the spring
latch bolt 44 from moving from the extended state to the retracted state.
As shown in FIG. 3, the spring latch bolt 44 is depicted in the extended
state while the dead latch bolt 46 is depicted in its disable state. The
dead latch bolt 46, shown in phantom in FIG. 3, is depicted in its enable
state.
To comprehend the assembly of the door latch actuator 10, reference is made
to FIGS. 2 and 4. The strike plate 30 is adapted to connect to the driver
18. An elliptical-shaped structure 48 is rigidly attached between the
electric motor 24 and the gear assembly 26. The structure 48 is received
by a U-shaped slot 50 formed in the support bracket 32 attached to the
strike plate 30 for a nestled fit. The support bracket fastener 36
captures the remaining portion of the elliptically-shaped structure 48
while receiving a pair of prong portions 52 and 54 of the support bracket
32 to secure the driver 18 to the strike plate 30. Although one of
ordinary skill in the art would appreciate that there are many mechanical
methods to fasten the driver 18 to the strike plate 30, this particular
mechanical method not only secures the driver 18 to the strike plate 30
but also it prevents the driver from counter-rotating within the support
bracket 32 and the support bracket fastener 36 when the driver 18 is
actuated.
Shown in FIG. 2, the actuator element 16 is disposed to pivot about an axis
"A". A first trunnion pin 54 is concentrically positioned along axis "A"
and is operably connected to the actuator element 16. Trunnion pin 54 has
gear teeth and is received and driven by gear assembly 26 so that the
driver 18 causes the actuator element 16 to pivot about axis "A". A second
trunnion pin 56 is coaxially aligned along axis "A" and projects from the
other end of actuator element 16. One of ordinary skill in the art would
understand other commonly-known methods to operably connect the actuator
element 16 to the driver 18.
The support element 34 is adapted to attach to the strike plate 30 by
either applying an adhesive thereto or using a mechanical means such as by
employing screws, rivets or other commonly known fastener means. The
support element 34 is also adapted to pivotally receive the actuator
element 16. The second trunnion pin 56 projecting from actuator element 16
is received by a pin-receiving hole 58 in the support element 34. The
support element 34 not only helps to secure the driver 18 and the actuator
member 16 to the strike plate 30 but also acts as a guide when the
actuator element 16 pivots between the first and second actuator
positions. For purposes of the preferred exemplary embodiment only, the
support element 34 includes a stop portion 60 which is adapted to restrict
movement of the actuator element 16 between the first and second actuator
positions while the actuator element 16 pivots therebetween.
The strike plate 30 has a port 62 which is adapted so that the spring latch
bolt bolt 44 and the dead latch bolt 46 may extend therethrough and into
the latch bolt receiving cavity 12 in the doorjamb 14. Holes 64 and 66 are
formed into the strike plate 30. As shown in FIG. 4, wood screws 68 are
driven through holes 64 and 66 to releasably attach the strike plate 30 to
the doorjamb 14 and over the latch bolt receiving cavity 12. Strike plate
30 with its port 62 acts with latch bolt receiving cavity 12 to provide a
bolt receiver that receives the spring latch bolt 44. Alternatively, the
bolt receiver could be provided solely by the actuator element 16.
When the door latch actuator 10 is mounted in the latch bolt receiving
cavity 12 in the doorjamb 14, the actuator element 16 is disposed in
proximity to a distal end 69 of the spring latch bolt 44 and a distal end
70 of the dead latch bolt 46 as depicted in FIG. 5(a). The actuator
element 16 is movable between a first actuator position as shown in | | |