Dual action latch retractor

Information

  • Patent Grant
  • 6565130
  • Patent Number
    6,565,130
  • Date Filed
    Wednesday, December 5, 2001
    22 years ago
  • Date Issued
    Tuesday, May 20, 2003
    21 years ago
Abstract
An exit bar employs a dual action latch retractor comprising a slotted link which connects manual and electrically actuated latch retraction means. The slot permits the latch to be retracted by a solenoid latch retractor regardless of the position of the push bar or other manual latch retraction means. A buffer spring transmits energy from the solenoid latch retractor to the push pad so that under normal circumstances actuation of the solenoid latch retractor retracts both the latch and push pad. However, if the push pad is jammed in the projected position, the buffer spring is compressed to permit relative movement between the solenoid latch retractor and the manual latch retraction mechanism. As soon as the force holding the push pad in an extended position is removed, the energy stored in the buffer spring is applied to the push pad through the mechanical linkage to retract the push pad.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention relates to the field of door security systems. More specifically, this invention relates to the use of a push or exit bar for securing a doorway.




2. Description of the Related Art




Exit bars, also known as push bars or panic bars, that allow egress through a doorway while limiting ingress are well-known components of door security and emergency systems. The conventional exit bar is mounted on the interior side of the door to be secured and is oriented generally horizontally across the face of the door. A housing or frame supports a push pad or bar for receiving a push force. The push force applied to the movable push pad operates a door latch through a linkage to permit opening of the door. Conventional exit bars typically employ a mechanical linkage between the movable push pad and the latch to actuate the latch mechanism for unlatching the door.




To avoid excessive wear to the exit bar components during periods of high traffic through a doorway, it is known to fix or “dog” the exit bar in an unlocked condition. Typically, the push pad is locked in its depressed or actuated position to avoid unnecessary wear to the associated linkage. It is also known to equip an exit bar with an electromagnetic latch retractor as described in U.S. Pat. No. 6,104,594, assigned to the assignee of the present invention. By integrating a building security system with exit bars including electromagnetic latch retractors, it is possible to effectuate the latching and unlatching of exit bars remotely and/or automatically.




U.S. Pat. No. 6,104,594 describes the use of an electric circuit to generate a high energy pulse through the electromagnet to generate a retraction force sufficient to retract the push pad and with it the mechanical linkage and latch to unlock the door. A possible deficiency of this approach is that, if the push pad is held or jammed in an extended position, the latch cannot be retracted by the electromagnet (even at high power). An alternative arrangement is to apply the electromagnetic retraction force only to the latch, without also retracting the push pad as described in U.S. patent application Ser. No. 09/414,202, filed Oct. 7, 1999 and also assigned to the assignee of the present invention. This permits latch retraction regardless of the position of the push pad. However, in high traffic situations, the push pad and its associated linkages are free to move as people push to open the door and are exposed to the resulting high rates of wear.




There is a need in the art for an exit bar equipped with remotely actuateable means for retracting the latch as well as the push pad which will reliably retract the latch even if the push pad is jammed in an extended position.




SUMMARY OF THE INVENTION




An object of the present invention is to provide a new and improved dual action latch retractor for retracting the push pad and latch of an exit bar that will reliably retract the latch regardless of the position of the push pad.




Another object of the present invention is to provide a new and improved dual action latch retractor for remotely retracting the push pad and latch of an exit bar.




These and other objects are achieved in an exit bar in which a slotted link is used to connect a solenoid latch retractor to the push pad and the associated manual latch retraction mechanism. The slot permits the latch to be retracted by the solenoid latch retractor regardless of the position of the push bar. A buffer spring transmits energy from the solenoid latch retractor to the push pad so that under normal circumstances actuation of the solenoid latch retractor retracts both the latch and push pad. However, if the push pad is jammed in the projected position, the buffer spring is compressed to permit relative movement between the solenoid latch retractor and the manual latch retraction mechanism. Compression of the buffer spring permits the latch to be retracted while the push pad remains in the extended position. As soon as the force holding the push pad in an extended position is removed, the energy stored in the buffer spring is applied to the push pad through the mechanical linkage to retract the push pad.











BRIEF DESCRIPTION OF THE DRAWINGS




Other objects and advantages of the invention will be evident to one of ordinary skill in the art from the following detailed description, made with reference to the accompanying drawings, in which:





FIG. 1

is a schematic view of an exit bar equipped with a dual action latch retractor in accordance with the present invention mounted to a door and illustrating various auxiliary features thereof;





FIG. 1A

is a partial enlarged front view of the exit bar of

FIG. 1

, with the push pad removed;





FIG. 2

is a sectional view through the exit bar of

FIG. 1A

, taken along line


2





2


thereof and including the push pad;





FIG. 3

is the sectional view of

FIG. 2

with the solenoid energized and the push pad in an extended position;





FIG. 4

is the sectional view of

FIG. 2

with the solenoid energized and the push pad in a retracted position;





FIG. 5

is a perspective exterior view of the exit bar of

FIG. 1A

with portions of the push pad and housing removed; and





FIG. 6

is a perspective view of the latch mechanism, mechanical linkage and solenoid latch retractor of the exit bar shown in

FIGS. 1A through 5

with the push pad, latch mechanism cover and housing removed.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




With reference to the drawings, wherein like numerals represent like components or structures throughout the several Figures, a preferred embodiment of an exit bar equipped with a dual action latch retractor in accordance with the present invention is generally designated by the numeral


10


. The exit bar


10


is mounted in a horizontal position across the interior side of a door


12


to be secured (FIG.


1


). The exit bar


10


latches against a strike


14


mounted to the door frame from which the door


12


is supported. A push force applied at the front of the exit bar


10


retracts the latch bolt


42


from the strike


14


and releases the door


12


to open for egress. Power is supplied to the exit bar


10


from a remote power source


22


over lines


24


in a conventional manner.




Exit bars in accordance with the present invention are readily adaptable for communication with a remote control or security system


26


. The remote security system


26


can be used to issue commands to the exit bar


10


to remotely unlatch the door and also to maintain the door in an unlatched state.




With reference to

FIGS. 1A through 6

, the exit bar


10


has an elongated main housing


32


which mounts to the door face to support and surround the exit bar internal components. The length of the housing


32


is preferably sufficiently long to substantially span the width of the door


12


. The main housing


32


is mounted to the door by means of screws or other fasteners (not shown) which secure the back panel


34


of the housing


32


in surface to surface disposition to the interior (secured) face of the door


12


. The main housing


32


is preferably a channel shaped extrusion defining an elongated opening spaced away from the face of the door


12


. A transversely displaceable push pad


36


defines a push face for receiving a push force exerted toward the door


12


by a person attempting egress through the door. The push pad


36


preferably spans a substantial longitudinal portion of the housing


32


adjacent that end of the housing closest the latch assembly


18


.




Fixed inside the main housing


32


is a frame


40


. The generally channel shaped frame


40


is secured to the back panel


34


of the main housing


32


by screws or other fasteners (not shown). For purposes of describing the invention as viewed in

FIGS. 1A through 6

, the main housing


32


defines a central longitudinal axis which extends parallel to the back panel


34


and a transverse axis which extends perpendicularly from the back panel


34


.




The exit bar secures the door by use of a latch assembly


18


that may encompass a variety of forms. The latch assembly includes a retractable or releasable latch bolt


42


which is pivotally mounted to a latch frame


20


. The latch bolt


42


is biased toward an extended or latched position by a latch pre load spring


23


that acts on a latch link


21


. A latch cover


19


surrounds the latch housing


20


to keep contaminants from the latch assembly


18


. When push pad


36


is pushed into the housing


32


by a person attempting egress, a pair of parallel push pad rails


44


mounted to the push pad


36


are moved toward the rear panel


34


of the exit bar


10


.




With reference to

FIGS. 2 through 4

, the push pad


36


is mounted to longitudinally extending rails


44


which are pivotally linked to the frame


40


by a master main link


50


and a slave main link


52


. The master main link


50


and slave main link


52


are pivotally connected to the rails


44


by pins


54


,


56


respectively. As best seen in

FIG. 6

, a master main link pin


58


extends through the master main link


50


and slidably engages in master main link slots


60


defined by the frame


40


. In a similar construction, a slave main link pin


62


extends through the slave main link


52


and slidably engages in slave main link pin slots


64


defined by the frame


40


.




As viewed in

FIGS. 2 through 4

, the master and slave main links


50


,


52


extend from the rails


44


to almost the bottom of the channel defined by the frame


40


. A second master main link pin


66


extends through the master main link


50


and slidably engages in master main link lower slots


68


(hidden by auxiliary rail


80


in

FIGS. 2-4

) defined by frame


40


. A second slave main link pin


70


extends through the slave main link


52


and slidably engages in slave main link lower slots


72


defined by frame


40


. The master and slave lower guide slots


68


,


72


are oriented generally parallel to the back panel


34


of the housing


32


in the longitudinal direction. A main spring guide


76


is engaged by the second slave link pin


70


. A main spring


78


is compressively engaged between the main spring guide


76


and a flange formed by the frame


40


to bias the push pad


36


and associated master and slave main links


50


,


52


toward a projected position (best seen in FIGS.


2


and


3


).




Opposed auxiliary rails


80


connect the master and slave main links


50


,


52


at their second master and slave main link pins


66


,


70


. The construction of the master and slave main links


50


,


52


and the associated pins and slots define a transverse path of motion, e.g., toward the door, for the push pad


36


and rails


44


. Upon application of a push force, the transverse motion of the rails


44


and push pad


36


toward the door is translated into a generally longitudinal motion away from the latch


42


at second master main link pin


66


and second slave main link pin


70


. The provision of auxiliary rails


80


linking second master and slave main link pins


66


,


70


ensures that a push force applied to either end of the push bar


36


will result in a substantially equivalent longitudinal motion at the bottom of the master main link


50


.




The master and slave main links


50


,


52


, master and slave link slots


60


,


64


, lower guide slots


68


,


72


, rails


44


, push pad


36


and auxiliary rails


80


act in concert to form a manual latch retraction mechanism which translates a push force applied to the push pad into a longitudinal latch retraction force at the second master main link pin


66


located at the bottom of the master main link


50


. As best seen in

FIGS. 2-4

, the second master main link pin


66


passes through a slot


67


defined by a solenoid link


90


. The solenoid link is operatively connected between a solenoid plunger


94


and latch link


21


for transmitting a retraction force generated by the solenoid


92


to the latch assembly


18


. An adjuster


96


(best seen in

FIG. 6

) fixes one end of the solenoid link to the solenoid plunger


94


. The adjuster permits fine tuning of the position of the solenoid link relative to the solenoid plunger


94


and solenoid


92


. The adjuster


96


has a shaft that penetrates an axial bore in the solenoid plunger


94


. The shaft is fixed in a selected position relative to the plunger


94


by set screws (not shown) in bores that intersect the axial bore.




As best seen in

FIGS. 1A

,


5


and


6


, the solenoid link defines a yoke comprising two transversely spaced arms which extend longitudinally toward the latch assembly before bending toward each other to define a parallel, closely spaced connection on either side of the latch link


21


. Solenoid link


90


and latch link


21


are connected by a pin


17


which is slidably engaged in longitudinal slots


15


defined by the frame


40


(see FIG.


6


).




A coiled buffer spring


100


surrounds a buffer spring guide


98


disposed between the arms of the solenoid link


90


. Pin


66


passes through one end of the buffer spring guide to fix the guide relative to the lower end of the master main link


50


. The closely spaced arms of the solenoid link


90


define a solenoid link slot


67


. Second master main link pin


66


extends transversely through the outer auxiliary rails


80


, lower guide slots


68


defined by the frame, master main link


50


, solenoid link slot


67


and the buffer spring guide


98


. Thus, the second master main link pin


66


is movable in a longitudinal direction relative to the frame


40


in longitudinal slots


68


and also in solenoid link slot


67


relative to the solenoid link.




The function of an exit bar


10


equipped with a dual-action latch retractor in accordance with the present invention will now be described with reference to

FIGS. 1A through 6

.

FIGS. 1A

,


2


,


5


and


6


illustrate the relative positions of the components of the exit bar


10


in a stable, latched condition. Latch


42


is biased toward its extended latched position by latch preload spring


23


, which is compressively engaged between a flange of the frame


40


and connecting pin


17


which joins the arms of the solenoid link


90


to the latch link


21


. Push pad


36


and the associated parts of the manual latch retraction mechanism are biased toward an outwardly projected position by main spring


78


. Main spring


78


is compressively engaged between the main spring guide


76


and a flange projecting from the frame


40


. It should be noted that latch preload spring


23


biases the latch


42


toward its projected latched position and also biases the solenoid link


90


and attached solenoid plunger


94


toward the position illustrated in FIG.


2


.




A push force applied to the push pad is coupled by rails


44


to the upper end of the master and slave main links


50


,


52


through pins


54


,


56


. The master and slave main links


50


,


52


move inwardly relative to the exit bar housing


32


and frame


40


with master main link pin


58


and slave main link pin


62


guided in master and slave main link pin slots


60


,


64


. It should be noted that the master and slave main link slots


60


,


64


are angled such that movement of the push pad


36


relative to the exit bar housing


32


and latch cover


19


is substantially perpendicular, e.g., toward the face of the door


12


. The inward and pivoting movement of master and slave main links


50


,


52


in response to a push force causes master and slave second main link pins


66


,


70


to move longitudinally away from the latch assembly


18


in slots


68


,


72


. When the push bar has been fully compressed into the exit bar housing


32


by a push force, second main link pin


66


has reached the end of solenoid link slot


67


and exerted a retraction force on the latch


42


via the latch link


21


(see FIG.


4


). In this position, the main spring


78


is compressed between the main spring guide and the frame


40


. Buffer spring


100


is not compressed because the relative positions of the solenoid link


90


and the master main link


50


lower end have not changed. In other words, second main link pin


66


is still at the right hand end of solenoid link slot


67


. Release of the push force against the push pad


36


will permit the main spring


78


and latch pre load spring


23


to return the components of the exit bar to their extended latched positions as illustrated in FIG.


2


.




An exit bar


10


equipped with a dual-action latch retractor in accordance with the present invention may also be unlocked, e.g., latch


42


retracted, by actuation of solenoid


92


. The exit bar


10


is equipped with control electronics


110


for generating current in solenoid


92


to produce a magnetic field which in turn creates a retraction force on solenoid plunger


94


. Solenoid, link


90


and connected latch link


21


apply the retraction force generated by the solenoid to the latch


42


. The dual-action latch retractor in accordance with the present invention is configured to retract both the latch


42


and the push bar


36


with its associated linkages. Retracting the latch


42


releases the door


12


for egress while retracting the push pad


36


and its associated manual latch retraction mechanism avoids excessive wear on the mechanism during periods of high traffic through the door.




Since the latch retraction force generated by the solenoid must also retract the push pad


36


and its associated manual latch-retraction mechanism, the initial force generated by the solenoid


92


must be substantial. Therefore, the control electronics


110


are capable of generating an initial high-current pulse to overcome the inertia of the push pad


36


and its associated manual latch retraction mechanism as well as overcoming the force exerted on the latch by the latch preload spring


23


. Maintaining the components of the exit bar in the positions illustrated in

FIG. 4

requires less current than the initial movement thereto, so the control electronics also provide a lower current retaining power to the solenoid


92


following the initial retraction pulse.




In accordance with a particular aspect of the present invention, the dual-action latch retractor is provided with means for permitting relative movement between the solenoid link


90


and the lower end of the master main link


50


(second master main link pin


66


). This allows the retraction force generated by the solenoid


92


to retract the latch


42


regardless of the position of the push pad


36


and its associated manual latch-retraction mechanism. It is advantageous for the door to be capable of remote automated release even when the push pad


36


and/or the manual latch retraction mechanism are jammed in their extended latched positions. Further, it is advantageous that when the jamming force is released, the dual-action latch retractor then retract the push pad


36


and its associated manual latch-retraction mechanism to avoid wear commonly associated with high traffic situations.




These objects are achieved in the illustrated preferred embodiment by applying the retraction force generated by the solenoid


92


to the master main link


50


through a buffer spring


100


. When the push bar is free to move and the solenoid is actuated, the buffer spring


100


efficiently transmits the retraction force to the lower end of the master main link


50


to retract the push pad and the manual latch-retraction mechanism. If the push pad is jammed, as illustrated in

FIG. 3

, the solenoid


92


is still capable of retracting the latch


42


via the solenoid link


90


and the latch link


21


. The buffer spring


100


is compressed by the altered relative positions of the master main link second pin


66


and the solenoid link


90


. As can be seen in

FIG. 3

, pin


66


has moved to the left end of solenoid link slot


66


thereby compressing the buffer spring


100


which is engaged between the buffer spring guide


98


and the solenoid link


90


. When the jamming force is removed, energy stored in the compressed buffer spring


100


is sufficient to retract the push pad and the associated manual latch-retraction mechanism.




Thus, the dual-action latch retractor in accordance with the present invention is capable of retracting both the latch and the manual latch-retraction mechanism of an exit bar regardless of the position of the push pad relative to the exit bar housing


32


. The exit bar


10


is fully integratable with building security and alarm systems, permitting remote automatic release and dogging of the latch and manual latch-retraction mechanisms, respectively.




While a preferred embodiment of the foregoing invention has been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the present invention.



Claims
  • 1. A dual action latch retractor comprising:an actuator electrically actuatable to generate a first latch retraction force; a solenoid link extending from a first end fixed to said actuator to a second end operatively connected to retract a latch and comprising means for permitting relative movement between said solenoid link and a manual latch retraction mechanism operatively connected to said solenoid link; said manual latch retraction mechanism configured to translate a manual force applied to an operator into a second latch retraction force and apply said second latch retraction force to said solenoid link to retract said latch, said manual latch retraction mechanism biased toward a first position and movable to a second position to retract said latch in response to application of said manual force to said operator; and bias means for biasing, said manual latch retraction mechanism relative to said solenoid link so that said first retraction force is applied through said bias means and said manual latch retraction mechanism to move said operator from said first position to said second position, wherein said means for permitting relative movement permits retraction of said latch by said first latch retraction force regardless of the position of said manual latch retraction mechanism.
  • 2. The dual action latch retractor of claim 1, wherein said actuator comprises a solenoid including an electromagnet and a plunger attracted by a magnetic field generated by said electromagnet to generate said first latch retraction force, said solenoid link first end being fixed to said plunger.
  • 3. The dual action latch retractor of claim 1, wherein said bias means comprises a buffer spring and when said first latch retraction force is applied to said solenoid link with said manual latch retraction mechanism held in said first position, said buffer spring compresses to store a portion of said first latch retraction force and when said manual latch retraction mechanism is released, said buffer spring applies said stored force through said manual latch retraction mechanism to move said operator from said first position to said second position.
  • 4. The dual action latch retractor of claim 1, wherein said means for permitting relative movement comprises a slot in said solenoid link and said manual latch retraction mechanism is operatively connected to said solenoid link by a pin movable in said slot.
  • 5. The dual action latch retractor of claim 1, wherein said means for permitting relative movement comprises a slot in said solenoid link and said manual latch retraction mechanism is operatively connected to said solenoid link by a pin movable in said slot, said dual action latch retractor further comprising a buffer spring guide connected to said manual latch retraction mechanism by said pin and including protrusions,wherein said buffer spring surrounds said buffer spring guide and is compressibly engaged between said solenoid link and said protrusions such that movement of said pin in said slot caused by said manual latch retraction mechanism being held in said first position during application of said first latch retraction force to said solenoid link compresses said buffer spring and when said manual latch retraction mechanism is released, said buffer spring expands to move said manual latch retraction mechanism from said first position to said second position.
  • 6. The dual action latch retractor of claim 3, wherein said operator and manual latch retraction mechanism are biased toward said first position by a main spring having an axis, said buffer spring having an axis parallel to said main spring axis.
  • 7. The dual action latch retractor of claim 2, wherein said solenoid plunger includes an adjuster for fixing said solenoid link first end in a selected position relative to said plunger and electromagnet.
  • 8. An exit bar comprising:a retractable latch biased toward a projected latched position; a manual latch operator operatively connected to a manual latch retraction mechanism, a force applied to said operator being translated by said manual latch retraction mechanism into a first latch retraction force, said operator and manual latch retraction mechanism movable between a first latched position and a second latch retraction position; a solenoid comprising a coil and a plunger, an electrical current applied to said coil generating a second latch retraction force; a mechanical connection between said latch, said manual latch retraction mechanism and said solenoid plunger comprising a solenoid link; and means for selectively permitting relative movement between said manual latch retraction mechanism and said solenoid link, said means for selectively permitting relative movement including a slot in said solenoid link, a pin slidable in said slot and engaged with said manual latch retraction mechanism, a buffer spring operatively connected so that said second latch retraction force is transmitted to said manual latch retraction mechanism through said buffer spring, wherein if said operator is held in said first latched position during application of said second latch retraction force, said buffer spring is compressed and when said operator is released, said compressed buffer spring releases energy to move said operator and manual latch retraction mechanism to said second retraction position, said relative movement occurring when said manual latch operator fails to move in response to said second latch retraction force, wherein said first latch retraction force moves said solenoid link to retract said latch and said second latch retraction force moves said solenoid link to retract said latch regardless of the position of said operator and manual latch retraction mechanism.
  • 9. An exit bar comprising:a retractable latch biased toward a projected latched position; a solenoid comprising a coil and a plunger, an electrical current applied to said coil generating a first retraction force; a mechanical connection between said latch and said solenoid plunger comprising a solenoid link, said solenoid link defining a slot; a manual latch retraction mechanism including an operator for receiving a manual latch retraction force which, when applied to said operator is translated by said manual latch retraction mechanism into a second retraction force, said operator and manual latch retraction mechanism movable between a first latched position and a second latch retraction position; a buffer spring arranged such that said first retraction force is applied to said manual latch retraction mechanism through said buffer spring; and a buffer spring guide fixed relative to said pin, wherein said buffer spring surrounds said buffer spring guide and is compressively engaged between said buffer spring guide and said solenoid link, and wherein said manual latch retraction mechanism is operatively connected to said solenoid link by a pin slidably engaged in said slot such that said second retraction force moves said solenoid link to retract said latch and said first retraction force moves said solenoid link to retract said latch regardless of the position of said operator and manual latch retraction mechanism.
  • 10. The exit bar of claim 9, further comprising a main spring having an axis and operatively connected to bias said manual latch retraction mechanism and operator toward said first latched position, said buffer spring having an axis parallel to said main spring axis.
  • 11. The exit bar of claim 10, wherein said latch is biased toward said projected latched position by a latch preload spring having an axis parallel to said main spring axis and buffer spring axis.
  • 12. An exit bar comprising:a retractable latch biased toward a projected latched position; a solenoid comprising a coil and a plunger, an electrical current applied to said coil generating a first retraction force; a mechanical connection between said latch and said solenoid plunger comprising a solenoid link, said solenoid link defining a slot; a manual latch retraction mechanism including an operator for receiving a manual latch retraction force which, when applied to said operator is translated by said manual latch retraction mechanism into a second retraction force, said operator and manual latch retraction mechanism movable between a first latched position and a second latch retraction position; and a buffer spring arranged such that said first retraction force is applied to said manual latch retraction mechanism through said buffer spring; wherein said solenoid link comprises two spaced apart arms defining a yoke and said buffer spring is disposed between said arms, and wherein said manual latch retraction mechanism is operatively connected to said solenoid link by a pin slidably engaged in said slot such that said second retraction force moves said solenoid link to retract said latch and said first retraction force moves said solenoid link to retract said latch regardless of the position of said operator and manual latch retraction mechanism.
  • 13. The exit bar of claim 12, comprising a main spring having an axis and operatively connected to bias said manual latch retraction mechanism and operator toward said first latched position, said buffer spring having an axis parallel to said main spring axis.
  • 14. The exit bar of claim 13, wherein said latch is biased toward said projected latched position by a latch preload spring having an axis parallel to said main spring axis and buffer spring axis.
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Number Name Date Kind
3854763 Zawadzki Dec 1974 A
4801163 Miller Jan 1989 A
4976476 Cross Dec 1990 A
5018375 Tully May 1991 A
5340171 Slaybaugh Aug 1994 A
5421178 Hamel Jun 1995 A