Door locking and operating mechanism

Information

  • Patent Grant
  • 6585303
  • Patent Number
    6,585,303
  • Date Filed
    Tuesday, September 26, 2000
    23 years ago
  • Date Issued
    Tuesday, July 1, 2003
    21 years ago
Abstract
A door locking mechanism for deadlocking a door. The door locking mechanism includes a lockhead member which includes a door stopping portion. The lockhead member is moveable from a locked position, wherein the door is double deadlocked, and an unlocked position. A vertical locking mechanism is coupled to the lockhead member, and the vertical locking mechanism deadlocks the door when the lockhead member is in the locked position. The door stopping portion of the lockhead member also deadlocks door when the lockhead member is in the locked position. A carriage assembly is engaged with the door, and the carriage assembly is engageable with the door stopping portion and moves the lockhead member from the locked position to the unlocked position. The vertical locking mechanism disengages the door when the lockhead member is in the unlocked position and the door stopping portion of the lockhead member also disengages the door.
Description




BACKGROUND




The present invention generally relates to door locking and operating mechanisms, such as to door locking and operating mechanisms which are often employed in prisons. The invention more specifically relates to a door locking and operating mechanism which can readily be configured for use with a right or left-handed door.




Typically, door locking and operating mechanisms, such as those which are often employed in prisons, are “handed,” meaning that a given mechanism is configured to work either with a door which opens to the left (a “left-handed door”) or with a door which opens to the right (a “right-handed door”). Specifically, a typical door locking and operating mechanism consists of several individual components, some of which are “handed.” In other words, a “left-handed” mechanism (a door locking and operating mechanism which is designed for use with a left-handed door) has parts which generally cannot be readily used in a “right-handed” mechanism (a door locking and operating mechanism which is designed for use with a right-handed door). Hence, prison maintenance staff, for example, must keep in stock an inventory of “left-handed” parts (for use in a left-handed mechanism) as well as an inventory of “right-handed” parts (for use in a right-handed mechanism).




Such “handed” mechanisms also generally provide that the parts are generally widespread in the mechanism and that each part must be individually installed into a housing over a door frame. As a result, replacing an entire mechanism is generally tedious and time consuming.




Many of the mechanisms provide that a vertical lock bar locks the door in place. However, the mechanisms also provide that the vertical lock bar can be manually manipulated from the bottom of the vertical lock bar, such as by an object inserted under the door, to lift the vertical lock bar and unlock the door. Of course, in situations where it is important to have strict security, such as in prisons, this is not desirable.




OBJECTS AND SUMMARY




An object of an embodiment of the present invention is to provide a door locking and operating mechanism which is generally “non-handed” in that the mechanism can be employed with a left or right-handed door without having to substitute parts.




Another object of an embodiment of the present invention is to provide an easily attachable or detachable self-contained device mechanism plate with selectable handing for use with either left hand or right hand door housings.




Still another object of an embodiment of the present invention is to provide a door locking and operating mechanism which provides that a vertical lock mechanism cannot generally be manually manipulated from the bottom of the vertical lock bar, such as by an object inserted under the door, to lift the vertical lock bar and unlock the door.




Briefly, and in accordance with at least one of the foregoing objects, the present invention provides a door locking mechanism which includes a lockhead member which includes a door stopping portion. The lockhead member is moveable from a locked position, wherein the door is double deadlocked, and an unlocked position. A vertical locking mechanism is coupled to the lockhead member, and the vertical locking mechanism deadlocks the door when the lockhead member is in the locked position. The door stopping portion of the lockhead member also deadlocks the door when the lockhead member is in the locked position. A carriage assembly is engaged with the door, and the carriage assembly is engageable with the door stopping portion and moves the lockhead member from the locked position to the unlocked position. The vertical locking mechanism disengages the door when the lockhead member is in the unlocked position and the door stopping portion of the lockhead member also disengages the door. A motor is driveably engaged with the carriage assembly. Movement of the carriage assembly causes the carriage assembly to engage the door stopping portion of the lockhead member and move the lockhead member to the unlocked position.











BRIEF DESCRIPTION OF THE DRAWINGS




The organization and manner of the structure and function of the invention, together with further objects and advantages thereof, may be understood by reference to the following description taken in connection with the accompanying drawings, wherein like reference numerals identify like elements, and in which:





FIG. 1

is a front view of a door locking and operating mechanism, showing the mechanism mounted to a door frame and employed with a left-handed door, and showing the door in a closed position;





FIG. 2

is a right perspective view of the door locking and operating mechanism which is illustrated in

FIG. 1

, showing the mechanism employed with the door;





FIG. 3

is another right perspective view of the door locking and operating mechanism which is illustrated in

FIG. 1

, omitting a carriage assembly which has been removed from engagement with a motor of the mechanism and omitting a master bar of the mechanism;





FIG. 4

is a top perspective view of the door locking and operating mechanism which is illustrated in

FIG. 1

, omitting a carriage assembly which has been removed from engagement with a motor of the mechanism;





FIG. 5

is a view similar to that of

FIG. 4

, but omitting a panel and motor control circuit which have been removed from a motor bracket;





FIG. 6

is a left side perspective view of the door locking and operating mechanism which is illustrated in

FIG. 1

, showing a carriage assembly deadlocked behind a door stopping portion of a lockhead member of the device and showing the door stopping portion riding up an incline surface of the carriage assembly;





FIG. 7

is a right side perspective view of the door locking and operating mechanism which is illustrated in

FIG. 1

, showing the door stopping portion of the lockhead member before it rides down another incline surface of the carriage assembly;





FIG. 8

is a view similar to

FIG. 7

, showing the door stopping portion of the lockhead member of the device riding down the other incline surface of the carriage assembly to deadlock the door in an open position;





FIG. 9

is a bottom perspective view of a portion of the mechanism illustrated in

FIG. 1

, omitting the carriage assembly which has been removed from engagement with a motor of the mechanism;





FIG. 10

is a view similar to that of

FIG. 9

, but omitting a motor bracket which has been removed from engagement with a mechanism plate;





FIG. 11

is a front view of a portion of the mechanism illustrated in

FIG. 1

, showing the carriage assembly locked to the right of the door stopping portion of the lockhead member;





FIG. 12

is a view similar to that of

FIG. 11

, showing the carriage assembly being driven to the left thereby causing the door stopping portion of the lockhead member to ride up an incline surface of the carriage assembly;





FIG. 13

is a view similar to that of

FIG. 12

, showing the carriage assembly being further driven to the left after the door stopping portion of the lockhead member has ridden up the incline surface of the carriage assembly;





FIG. 14

is a view similar to that of

FIG. 13

, showing the mechanism after the door stopping portion of the lockhead member has ridden down the other incline surface of the carriage assembly, thereby deadlocking the door in the open position;





FIG. 15

is a view similar to that of

FIG. 11

, showing a master bar engaging the lockhead member causing the door stopping portion of the lockhead member to move out of the way of the carriage assembly and a deadlock at the bottom of the door to disengage; and





FIG. 16

is a block diagram of electronics of the mechanism shown in the previous FIGURES.











DETAILED DESCRIPTION OF THE INVENTION




While the present invention may be susceptible to embodiment in different forms, there is shown in the drawings, and herein will be described in detail, embodiments with the understanding that the present description is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to that as illustrated and described herein.




Illustrated in the FIGURES is a door locking and operating mechanism


10


(some FIGURES only show one or more portions of the mechanism


10


) which is configured for engagement with a door


12


and a door housing


14


. Specifically, the mechanism


10


is configured to open and close a door


12


, and deadlock the door in place in either the open or closed position. The mechanism


10


can be utilized with a left-handed door (as shown in

FIGS. 1 and 2

) as well as a right-handed door, and can be easily and quickly installed or replaced. Still further, the mechanism


10


provides a vertical lock mechanism


16


which cannot generally be manually manipulated, such as by inserting an object under the door


12


, to unlock the door


12


and breach security. The mechanism


10


provides still other advantages which will be evident to one having ordinary skill in the art after reviewing the following description.




As shown, the door locking and operating mechanism


10


preferably includes a mechanism plate


18


which is configured for mounting to the door housing


14


above the door


12


. The mechanism plate may be a ¼″×10″×16″ steel plate which is mountable to the door housing


14


using four (4) {fraction (5/16)}-18 cap screws


20


. Preferably, the mechanism


10


is configured to be mounted generally over a center column


22


of the door housing


14


, and the mechanism plate


18


provides that the mechanism


10


is generally centralized and relatively compact. This is in contrast to many prior art mechanisms which are more spread out and are not generally centrally mounted on a single plate. Instead, many prior art mechanisms have the individual components mounted directly to the door frame such that the entire mechanism cannot be replaced or installed merely by installing a single mechanism plate which has several components mounted thereon.




As shown most clearly in

FIG. 10

, lockhead guides


24


are secured to the mechanism plate


18


, and the lockhead guides


24


define a channel


26


which receives a lockhead member


28


. The channel


26


defined by the lockhead guides


24


preferably provides that the lockhead member


28


can move generally up and down, but not side to side, relative to the mechanism plate


18


and the center column


22


of the door housing


14


(see FIG.


1


).




Preferably, when the lockhead member


28


moves in the channel


26


, it operates a vertical locking mechanism


16


for deadlocking the door


12


. As shown in

FIGS. 11-15

, the vertical locking mechanism


16


may consist of a vertical lock bar


30


which is pinned to the lockhead member


28


and which extends through and is generally contained in the center column


22


of the door housing


14


(see FIG.


1


), otherwise referred to as the vertical lock column. As shown in FIGS.


1


and


6


-


15


, a bracket


32


may be provided generally at the bottom of the lockhead member


28


, and a pin may be secured through the bracket


32


and through the top of the vertical lock bar


30


, thereby pinning the top of the vertical lock bar


30


to the lockhead member


28


. As shown in

FIGS. 11-15

, the bottom


34


of the vertical lock bar


30


is preferably beveled and engages a steel ball


36


which is received in a recess


38


,


40


in the bottom of the door


12


, thereby deadlocking the door


12


. Preferably, the vertical lock bar


30


and the steel ball


36


are contained within the vertical lock column


22


(see FIG.


1


), and when the vertical lock bar


30


pushes down on the steel ball


36


, the steel ball


36


moves out of an opening in the vertical lock column


22


into engagement with one of two recesses


38


,


40


in the bottom of the door


12


, thereby deadlocking the door


12


as shown in

FIGS. 11 and 14

. The vertical lock column


22


may be a column of 1.5″ square heavy wall steel tubing.




As shown in

FIGS. 11-14

, preferably the door includes two recesses


38


,


40


—one proximate each edge of the door


12


. Hence, the vertical lock bar


30


and steel ball


36


can be operated to deadlock the door


12


in both the open and closed positions. Ideally, the recesses


38


,


40


in the bottom of the door


12


are also beveled, thereby providing that the steel ball


36


is generally biased into the vertical lock column


22


so the door


12


does not have a tendency to become jammed when the vertical lock bar


30


is not actively engaging the steel ball


36


. While the vertical locking mechanism


16


has been described as consisting of a vertical lock bar


30


, a steel ball


36


and recesses


38


,


40


in the door


12


for receiving the steel ball


36


from the center column


22


, one having ordinary skill in the art would recognize that the vertical locking mechanism


16


may take other forms.




As shown most clearly in

FIG. 10

, the lockhead member


28


preferably consists of a plate


50


which has two rollers


52


,


54


pinned thereto. Preferably, an upper roller


52


is configured to be engaged by a master bar


56


as shown in

FIGS. 5 and 15

. As shown in

FIG. 15

, the master bar


56


may be manipulated to effect a gang release from a control panel


58


(see also

FIG. 16

) or by manually actuating a lock which is provided in a release column


60


in the door housing


14


, where the release column


60


is located proximate the far edge of the door


12


when the door


12


is in the closed position (see FIG.


1


). To this end, the lock (not shown) is preferably cabled up to a bell crank and to the master bar


56


. One having ordinary skill in the art would recognize such an arrangement.




As shown in

FIG. 15

, engaging the master bar


56


with the upper roller


52


of the lockhead member


28


causes the lockhead member


28


to rise in the channel


26


defined by the lockhead guides


24


, and causes the vertical locking mechanism


16


to disengage the bottom of the door


12


(e.g. causes the vertical lock bar


30


to disengage the steel ball


36


and the steel ball


36


to fall out of the respective recess


38


,


40


in the bottom of the door


12


and back into the center column


22


) thereby causing the door


12


to unlock at the bottom of the door


12


. As shown in

FIGS. 6

,


11


and


14


, a lower roller


54


of the lockhead member


28


is configured to engage a carriage assembly


66


which is connected to the door


12


to provide an additional deadlock near the top of the door


12


, hence the lower roller


54


may be termed a door stopping portion of the lockhead member


28


. This will be described in more detail later below.




As shown in

FIGS. 6-12

and


14


, the lower roller


54


of the lockhead member


28


is received in a slot


68


, such as in a slanted slot, which is provided in a deadlock lever


70


. The deadlock lever


70


preferably consists of a plate


72


which is configured to move relative to the lockhead member


28


. As shown most clearly in

FIGS. 9 and 10

, preferably the plate


72


includes other slots


74


, such as generally horizontal slots, which receive bolts


76


which are bolted to the mechanism plate


18


(and, as shown, which possibly also extend through the lockhead guides


24


). The horizontal slots


74


provide that the deadlock lever


70


can move side-to-side relative to the lockhead member


28


, but not up and down along with the lockhead member


28


when the lockhead member


28


moves up and down in the channel


26


defined by the lockhead guides


24


which are secured to the mechanism plate


18


. The horizontal slots


74


provide that the riding of the lower roller


54


of the lockhead member


28


in the slot


68


in the deadlock lever


70


when the lockhead member


28


moves up or down in the channel


26


causes the deadlock lever


70


to move sideways relative to the lockhead member


28


and the mechanism plate


18


.




As shown in

FIGS. 1

,


3


and


6


-


14


, preferably the deadlock lever


70


includes a vertical locking mechanism obstructing portion


80


, such as a finger bolted to the plate


72


, for obstructing substantial actuation of the vertical locking mechanism


16


unless the deadlock lever


70


is first shifted sideways. Specifically, as shown in

FIGS. 1

,


3


,


6


,


8


-


11


and


14


, the finger prevents the vertical lock bar


30


from being lifted from the bottom of the door


12


, such as by sticking an object under the door


12


, unless the lockhead member


28


is first lifted. As shown in

FIGS. 7

,


12


,


13


, and


15


, when the lockhead member


28


is lifted in the channel


26


defined by the lockhead guides


24


, such as by actuation of the master bar


56


(see

FIG. 15

) or by operation of a motor


82


, which will be described later herein, the deadlock lever


70


shifts sideways causing the vertical locking mechanism obstructing portion


80


to mis-align from the top of the vertical lock bar


30


and the vertical lock bar


30


to lift with the lockhead member


28


. As shown, the deadlock lever


70


may include a cut out


84


at the bottom thereof to provide clearance for the top of the vertical lock bar


30


when the vertical lock bar


30


is lifted along with the lifting of the lockhead member


28


and the shifting of the deadlock lever


70


.




As shown in

FIGS. 1-9

, preferably a motor bracket


86


is secured to the mechanism plate


18


, and a motor


82


is secured to the motor bracket


86


. The motor


82


is preferably a ⅛ HP, 90 Volt DC variable speed, permanent magnet, right angle gear motor with a current limiting DC driver. The motor


82


may be mounted to the bottom of the motor bracket


86


and drive a pinion


88


or sprocket which engages and drives the carriage assembly


66


. Specifically, as will be described more fully later below, the motor


82


drives the carriage assembly to open/close and lock/unlock the door


12


.




As shown in FIGS.


1


and


4


-


9


, preferably the bracket


86


includes slots


90


which receive the master bar


56


, and two rollers


92


are secured to the motor bracket


86


and the master bar


56


rides on the rollers


92


. The master bar


56


may extend to one or more other mechanisms much like the one being described and therefore operate in association with more than one door. In such a case, the master bar would be relatively long and would be carried by a plurality of sets of rollers extending across the series of mechanisms. The slots


90


allow the master bar


58


to slide and the rollers


92


function to support the master bar


58


and facilitate the shifting of the master bar


58


thereby engaging the upper roller


52


and lifting the lockhead member


28


.




As shown in

FIGS. 3 and 4

(see also FIGS.


11


and


14


), preferably a plurality of limit switches


100


,


102


,


104


are mounted to the motor bracket


86


, and the limit switches


100


,


102


,


104


are configured to sense the carriage assembly


66


. The limit switches


100


,


102


,


104


are connected to a motor control circuit


106


(see, for example,

FIGS. 4 and 16

) which, preferably is mounted to the motor bracket


86


, such as on the top of the motor bracket


86


, opposite the motor


82


. Specifically, the motor control circuit


106


may include a circuit board


108


as well as a relay connection board


110


which provides easy access to relays and wiring connections. The motor control circuit


106


is connected to and controls the operation of the motor


82


depending on what is sensed by the limit switches


100


,


102


,


104


and depending on commands which are received from an operator through a control panel


58


(see FIG.


16


). As will be described later herein, operation of the motor


82


drives the door


12


opened or closed.




As shown in

FIGS. 7-10

, still another limit switch


112


may be mounted to the mechanism plate


18


and may be connected to the motor control circuit


106


for sensing the deadlock lever


70


and indicating to the motor control circuit


106


when the door


12


is deadlocked. The motor control circuit


106


is preferably configured to operate on either a 120 VAC or 24 Volt DC control and a 120 VAC power source. As shown in

FIG. 16

, preferably the motor control circuit


106


is connected to an indication device, such as to a control panel


58


(see FIG.


16


), which indicates whether the door.


12


is opened or closed and whether the door


12


is deadlocked, depending on what is sensed by the limit switches


100


,


102


,


104


,


112


. The motor control circuit


106


may also be configured to indicate, using the indication device (e.g. the control panel


58


) when the door


12


is in neither the open or closed position. In the case where the motor control circuit


106


is connected to a control panel


58


, which is preferred, the control panel


58


is configured to accept commands from an operator and to control the motor control circuit


106


to open and close, and lock and unlock the door


12


. Additionally, the control panel


58


indicates the status of the door


12


, such as whether the door


12


is open or closed and whether the door


12


is deadlocked. Of course, the control panel


58


may be wired to control and indicate the status of many doors, such as all the doors in a prison block.




As shown in

FIGS. 2

,


4


,


7


, and


8


, preferably a selector switch


114


is mounted to the motor bracket


86


and is connected to the motor control circuit


106


, and can be used to set the speed at which the motor


82


drives the door


12


. In the case of a relatively small door, it may be desirable to set the speed relatively slow, whereas in the case of a relatively large door, it may be desirable to set the speed relatively fast. The motor control circuit


106


may also include a selector switch


116


(see

FIG. 4

) for setting the “blocking force” of the door


12


, where the blocking force is the force it takes to stop the door


12


while the door


12


is moving, such as while it is being driven closed by the motor


82


. While it may be desirable to set the blocking force low if the door


12


is located in a corridor of a prison, it may be desirable to set the blocking force high if the door


12


is a cell door in a prison. The mechanism


10


preferably provides that a blocking force does not cause damage to the mechanism


10


.




Another selector switch


118


may be mounted on the motor bracket


86


and be connected to the motor control circuit


106


for setting a “soft stop” feature of the mechanism


10


. Specifically, the switch


118


may be set to select how much the door


12


slows down during the last portion of its range of movement in the closing direction. If the soft stop feature is provided, preferably a third limit switch


104


is mounted on the motor bracket, as shown in

FIG. 4

, and is connected to the motor control circuit


106


for sensing the carriage assembly


66


and indicating to the motor control circuit


106


when the door


12


is almost closed. The soft stop feature and other features of the opening and closing of the door


12


, including the function and operation of all of the limit switches


100


,


102


,


104


,


112


mentioned hereinabove, will be described more fully later herein.




As shown in

FIGS. 1

,


2


,


6


-


8


and


11


-


15


, the carriage assembly


66


preferably consists of two portions which are moveable relative to each other—a driven portion


130


and a following portion


132


. The driven portion


130


is configured to be driven by the motor


82


, such as by a pinion


88


or sprocket which is driven by the motor


82


. To this end, the driven portion


130


of the carriage assembly


66


preferably includes a geared rack


134


which is configured for engagement with the pinion


88


driven by the motor


82


. Alternatively, the driven portion


130


of the carriage assembly


66


may include a chain and a pair of positioning sprockets which engage the chain. In such a case, the chain would engage a sprocket which is driven by the motor


82


, and the sprocket which is driven by the motor


82


would engage the chain between the two positioning sprockets.




Regardless of whether the driven portion


130


of the carriage assembly


66


includes a geared rack


134


or a chain, preferably the carriage assembly


66


is configured to trip limit switches


100


,


102


,


104


mentioned hereinabove. Specifically, the carriage assembly


66


may include a plurality of extensions, or trippers, which are configured to trip the limit switches. Even more specifically, the carriage may include three trippers


136


,


138


,


140


for tripping each of the three different limit switches


100


,


102


,


104


which are mounted on the motor bracket


86


, wherein a first tripper


136


is generally at one end of the carriage assembly


66


and is configured to trip limit switch


100


to indicate to the motor control circuit


106


that the door


12


is in the open position, and wherein tripping the limit switch


100


causes the motor control circuit


106


to stop the motor


82


and indicate on the control panel


58


that the door


12


is open. A second tripper


102


is generally at the opposite end of the carriage assembly


66


and is configured to trip limit switch


102


on the motor bracket


86


to indicate to the motor control circuit


106


that the door


12


is in the closed position, wherein tripping the limit switch


102


causes the motor control circuit


106


to stop the motor


82


and indicate on the control panel


58


that the door


12


is closed. An additional, third tripper


140


, somewhat longer than the second tripper


138


, may be generally at the same end of the carriage assembly


66


as the second tripper


138


(on a right-handed door, the third tripper


140


would be provided generally at the same end of the carriage assembly


66


as the first tripper


136


) and be configured to trip the third limit switch


104


on the motor bracket


86


to indicate to the motor control circuit


106


that the door


12


is almost in the closed position, wherein tripping the limit switch


104


causes the motor control circuit


106


to slow the motor


82


down and effect a soft stop of the door


12


. Of course, the third limit switch


104


on the motor bracket


86


and the third tripper


140


on the carriage assembly


66


may or may not be included depending on whether a soft stop feature is desired.




In addition to the geared rack


134


(or the chain) and the trippers, the driven portion


130


of the carriage assembly


66


also preferably includes two incline surfaces


150


,


152


for engaging the door stopping portion


54


of the lockhead member


28


as well as a generally level surface


154


which generally spans between the incline surfaces


150


,


152


. Engagement of either incline surface


150


or


152


with the door stopping portion


54


of the lockhead member


28


causes the door stopping portion


54


to ride up the incline surface


150


,


152


to the generally level surface


154


, thereby causing the lockhead member


28


to rise in the channel


26


defined by the lockhead guides


24


, and cause the deadlock lever


70


to shift sideways. As shown in

FIGS. 7 and 13

, this causes the door stopping portion


54


to no longer block movement of the following portion


132


of the door


12


, and causes the vertical locking mechanism


16


to disengage the door


12


. Hence, the door


12


is unlocked from the top and bottom of the door


12


, and the door can be driven open or closed by the motor


82


.




As shown in

FIGS. 1

,


2


and


11


-


15


, the driven portion


130


of the carriage assembly


66


is keyed to the following portion


132


of the carriage assembly


66


, such as by bolts


156


on the driven portion


130


which are received in horizontal slots


158


on the following portion


132


. Such a configuration provides that when the driven portion


130


is initially driven by the motor


82


, the driven portion


130


can move even though the door stopping portion


54


of the lockhead member


28


initially prevents substantial movement of the following portion


132


of the carriage assembly


66


. As the driven portion


130


is moving, the bolts


156


ride in the slots


158


and after the door stopping portion


54


of the lockhead member


28


rides up the respective incline surface


150


,


152


of the driven portion


130


to the generally level surface


154


which generally spans the incline surfaces


150


,


152


the driven portion


130


pulls the following portion


132


. The following portion


132


is engaged with, such as bolted to, the door


12


, therefore, as the following portion


132


moves, the door


12


also moves.




As shown in

FIGS. 6 and 12

, as the door


12


is driven open, the door stopping portion


54


rides up one incline surface (thereby unlocking the door)


150


, rides across the generally level surface


154


(see

FIG. 13

) which spans the incline surfaces


150


,


152


and rides down the other incline surface


154


to again deadlock the door


12


as shown in FIG.


14


. Of course, as the door stopping portion


54


rides up the one incline surface


150


, the lockhead member


28


rises and the deadlock lever


70


shifts thereby causing the vertical locking mechanism


16


to release the door


12


(see FIGS.


7


and


12


), and as the door stopping portion


54


of the lockhead member


28


rides down the other incline surface


152


, the lockhead member


28


lowers and the deadlock lever


70


shifts back thereby causing the vertical locking mechanism


16


to again engage the door


12


(see FIG.


14


). Hence, as the lockhead member


28


rises, the door


12


is double unlocked and as the lockhead member


28


lowers back into place in the channel


26


, the door


12


is again double deadlocked.




The following portion


132


may be a travel bar assembly consisting of a pair of panels


160


,


162


which are generally parallel to each other and have a pair of rollers


164


pinned therebetween. As shown in

FIGS. 1

,


2


and


6


-


8


, the pair of rollers


164


are configured to ride on a guide member


170


or track on the door housing


14


and may be 3¾″ outside diameter turned steel with a double-shielded ball bearing attached to the carriage with a high tensile steel bolt and lock nut. Specifically, the guide member


170


may be a cylindrical metal bar which is welded to the door housing


14


. Preferably, as shown in FIGS.


2


and


6


-


8


, the rear panel


162


of the travel bar assembly extends further upward than the front panel


160


of the assembly. The front panel


160


of the assembly is preferably what has the horizontal slots


158


formed therein for receiving the bolts


156


of the driven portion


130


of the carriage assembly


66


. As shown, preferably it is also the front panel


160


of the travel bar assembly which is secured to the door


12


. Preferably, the door


12


is attached via eccentric bushings to allow vertical door adjustment.




As mentioned above, the door stopping portion


54


, when the lockhead member


28


is down in the channel


26


, aligns adjacent the carriage assembly


66


to deadlock the door


12


(see

FIGS. 8

,


11


and


14


). Specifically, it is the sides of the rear panel


162


of the travel bar assembly with which the door stopping portion


54


of the lockhead member


28


engages to deadlock the door


12


.




Operation of the mechanism


10


to open and close the door will now be described in detail. Initially, when the door


12


is closed as shown in

FIGS. 1

,


2


and


11


, the vertical locking mechanism


16


deadlocks the door


12


at the bottom of the door


12


(see FIG.


11


). Specifically, if the vertical locking mechanism


16


is provided as being the vertical lock bar


30


and steel ball


36


configuration which was discussed above, the vertical lock bar


30


engages the steel ball


36


into engagement with one of the recesses


38


,


40


in the bottom of the door


12


. Additionally, when the door


12


is in the closed position, the lockhead member


28


is in its lower position as shown in

FIGS. 9-11

. Hence, the deadlock lever


70


is not shifted and the vertical locking mechanism obstructing portion


80


is generally vertically aligned over the top of the vertical lock bar


30


. Hence, the vertical lock bar


30


cannot be lifted by sticking something under the door


12


.




Still further, when the door


12


is in the closed position and the lockhead member


28


is in its lower position, the door stopping portion


54


is generally aligned with the carriage assembly


66


(see

FIG. 11

) prohibiting the door


12


from being manually pushed open even if the vertical locking mechanism


16


were not engaged. Hence, when the door


12


is in the closed position, the door


12


is double deadlocked with the first deadlock resulting from the vertical locking mechanism


16


engaging the bottom of the door


12


and the second deadlock resulting from the door stopping portion


54


of the lockhead member


28


being aligned next to the carriage assembly


66


.




Also, when the door


12


is in the closed position, the carriage assembly


66


trips one of the limit switches


100


(the “closed limit switch”) as shown in

FIG. 11

, thereby indicating to the motor control circuit


106


that the door


12


is closed. As a result, this status is also indicated on the control panel


58


(see FIG.


16


). Additionally, the limit switch


112


which is on the mechanism plate


18


(the “lock status switch”) is tripped by the deadlock lever


70


as shown in

FIGS. 3 and 9

. Hence, the limit switch


112


indicates to the motor control circuit


106


that the door


12


is deadlocked, and this is also indicated on the control panel


58


(see FIG.


16


).




Preferably, if the door


12


is a three foot wide door, the control panel


58


can be commanded to have the mechanism


110


open the door


12


in six seconds or less. Also, while the door


12


is being opened or closed, the direction of movement of the door


12


preferably can be reversed electrically in mid-travel from the control panel


58


.




Upon actuating the control panel


58


to open the door


12


, the motor


82


drives the carriage assembly


66


, and more specifically, drives the driven portion


130


of the carriage assembly


66


. When the driven portion


130


is initially driven by the motor


82


, the driven portion


130


moves relative to the following portion


132


of the carriage assembly


66


. As the driven portion


130


is driven, the leading incline surface


150


on the carriage assembly


66


engages the door stopping portion


54


of the lockhead member


28


as shown in

FIGS. 6 and 12

, and the door stopping portion


54


rides up the incline surface


150


, causing the lockhead member


28


to rise in the channel


26


(see also

FIG. 7

) which is defined by the lockhead guides


24


. When the lockhead member


28


rises, the deadlock lever


70


shifts sideways (as a result of the door stopping portion


54


riding in the slanted slot


68


in the deadlock lever


70


) and the vertical lock bar


30


which is pinned thereto also rises, causing the steel ball


36


to disengage from the bottom of the door


12


(see FIG.


12


). As the motor


82


further drives the driven portion


130


, the door stopping portion


54


rides along the generally level surface


154


(see

FIGS. 7 and 13

) which spans the inclined surfaces


150


,


152


, and the following portion


132


, e.g. the travel bar assembly, follows the driven portion


130


. Hence, the door


12


begins to open. As the door


12


begins to open, the one limit switch (the “closed limit switch”)


100


which had been tripped by the carriage assembly


66


is no longer tripped, and this indicates to the motor control circuit


106


that the door


12


is not in the closed position. This status is also reported on the control panel


58


(see FIG.


16


). Additionally, as the door


12


begins to open, the deadlock lever


70


shifts. Therefore, the limit switch


112


which is provided on the mechanism plate


18


(the “lock status switch”) is no longer tripped by the deadlock lever


70


. This indicates to the motor control circuit


106


that the door


12


is not deadlocked, and the control panel


58


also reports this status.




As the door


12


is driven further open, the door stopping portion


54


rides along the generally level surface


154


to the other, trailing incline surface


152


. When the door stopping portion


54


rides down this incline surface


152


, the lockhead member


28


drops back down in the channel


26


and the deadlock lever


70


re-shifts back to its original position, as shown in

FIGS. 8-11

and


14


. As a result, the vertical locking mechanism


16


re-engages the door


12


as shown in

FIG. 14

(e.g. the steel ball


36


engages the other recess


40


provided in the bottom of the door


12


) and the door stopping portion


54


drops in place next to the carriage assembly


66


. Hence, the door


12


becomes double deadlocked in the open position. As the door


12


moves to the open position, the carriage assembly trips the other limit switch


102


(the “open limit switch”) as shown in

FIG. 14

, causing the motor control circuit


106


to stop the motor


82


. Additionally, the fact that the door


12


is in the open position is indicated on the control panel


58


. When the door


12


is in the open position and the lockhead member


28


is down in the channel


26


, the limit switch


112


on the mechanism plate


18


(the “lock status switch”) is again tripped by the deadlock lever


70


as shown in

FIGS. 8

,


9


,


11


and


14


. Hence, the control panel


58


also indicates that the door


12


is deadlocked.




Likewise, upon actuating the control panel


58


to close the door


12


, the motor


82


drives the carriage assembly


66


, and more specifically, drives the driven portion


130


of the carriage assembly. When the driven portion


130


is initially driven by the motor


82


, the driven portion


130


moves relative to the following portion


132


of the carriage assembly


66


. As the driven portion


130


is driven, the incline surface


152


on the carriage assembly


66


engages the door stopping portion


54


of the lockhead member


28


as shown in

FIG. 8

, and the door stopping portion


54


rides up the incline surface


152


, causing the lockhead member


28


to rise in the channel


26


which is defined by the lockhead guides


24


. When the lockhead member


28


rises, the deadlock lever


70


shifts sideways (as a result of the door stopping portion


54


riding in the slanted slot


68


in the deadlock lever


70


, see

FIG. 7

for example) and the vertical lock bar


30


which is pinned thereto also rises causing the steel bar


36


to disengage from the bottom of the door


12


(similar to

FIG. 12

, but at the other edge of the door). As the motor


82


further drives the driven portion


130


, the door stopping portion


54


rides along the generally level surface


154


which spans the inclined surfaces


150


,


152


, and the following portion


132


, e.g. the travel bar assembly, follows the driven portion


130


. Hence, the door


12


begins to close. As the door


12


begins to close, the one limit switch


102


(the “open limit switch”) which had been tripped by the carriage assembly


66


as shown in

FIG. 14

when the door


12


was in the open position is no longer tripped, indicating to the motor control circuit


106


that the door


12


is not in the open position. This is indicated on the control panel


58


(see FIG.


16


). Additionally, as the door


12


begins to close, the deadlock lever


70


shifts. Therefore, the limit switch


112


which is provided on the mechanism plate


18


(the “lock status switch”) is no longer tripped by the deadlock lever


70


. This indicates to the motor control circuit


106


that the door


12


is not deadlocked, and this is also reported on the control panel


58


.




As the door


12


is driven further closed, the carriage assembly


66


trips limit switch


104


(the “soft stop limit switch”), if provided, which indicates to the motor control circuit


106


that the door


12


is almost closed. In response, the motor control circuit


106


slows down the motor


82


to effect a soft stop of the door


12


. As the door


12


is even further closed, the door stopping portion


54


rides down the other incline surface


150


as shown in

FIGS. 6 and 12

, the lockhead member


28


drops back down in the channel


26


and the deadlock lever


70


re-shifts. As a result, the vertical locking mechanism


16


re-engages the door


12


(see

FIG. 11

) (e.g. the steel ball


36


re-engages the first recess


38


provided in the bottom of the door


12


) and the door stopping portion


54


drops in place next to the carriage assembly


66


. Hence, the door


12


becomes double deadlocked in the closed position. As the door


12


moves to the completely closed position, the carriage assembly


66


trips limit switch


100


(the “closed limit switch”) (see

FIG. 11

) causing the motor control circuit


106


to stop the motor


82


. Additionally, the fact that the door


12


is in the closed position is indicated on the control panel


58


. When the door


12


is in the closed position and the lockhead member


28


is down in the channel


26


, the limit switch


112


on the mechanism plate


18


(the “lock status switch”) is tripped by the deadlock lever


70


. Hence, the control panel


58


also indicates that the door


12


is deadlocked.




In addition to using the control panel


58


to direct the motor control circuit


106


to drive the carriage assembly


66


to open or close the door


12


, the control panel


58


and motor control circuit


106


may also be configured to actuate the master bar


56


. In such a case, the master bar


56


shifts and lifts the lockhead member


28


as shown in FIG.


15


. Hence, the door


12


becomes double unlocked, and the door


12


can be manually opened or closed. However, the motor


82


does remain engaged with the carriage assembly


66


, therefore the door


12


is not freewheeling. As mentioned above, the master bar


56


also may be, configured to be actuated by a key in a release column


60


(see FIG.


1


), such as during routine use or in case of emergency or a power failure.




As shown, it is preferred that the lockhead member


28


, the deadlock lever


70


and the motor bracket


86


be secured to the mechanism plate


18


. Hence, the arrangement of components is generally centralized on the mechanism plate


18


above the central column


22


of the door


12


as shown in FIG.


1


. This renders the overall mechanism


10


particularly quick and easy to install or replace.




The mechanism


10


is also easy to configure for either a right-handed or left-handed door, and this will now be described in more detail. As discussed above, the motor drive assembly


106


operates the motor


82


based on what is sensed by the limit switches


100


,


102


,


104


and what commands are received by the control panel


58


. Particularly, tripping of the limit switches


100


,


102


causes the motor control circuit


106


to stop the motor


82


, or slow the motor


82


down (in case the soft stop limiting switch


104


is tripped), and causes the correct status of the door


12


to be indicated on the control panel


58


. While many prior art door locking systems provide a limit switch at each edge of a door and that the limit switches are connected to a motor control circuit, the one limit switch is configured to indicate to the circuit that the door is closed and the other is configured to cause the circuit to stop the motor. In contrast, motor control circuit


106


provides that the limit switches


100


,


102


can be reconfigured upon switching one or more switches


172


,


174


(“door type selection switches”) on the motor control circuit as shown in

FIGS. 4 and 16

.




Specifically, a first door type selection switch


172


defines the functioning of the limit switch


100


which is proximate the one end of the door


12


when the door


12


is closed, and the second door type selection switch


174


defines the functioning of the limit switch


102


which is proximate the other end of the door


12


when the door


12


is closed. Regardless of the setting of the two switches


172


,


174


, both limit switches


100


,


102


dictate when the motor control circuit


106


stops the motor


82


. However, upon both door type selection switches


172


,


174


being in one position (for example, for a “left-handed door”), the one limit switch


100


dictates when the door


12


is indicated as being closed, and upon both door type selection switches


172


,


174


being in the other, opposite position (for example, for a “right-handed door”), the other limit switch


102


dictates when the door


12


is indicated as being closed. In other words, when the door type selection switches


172


,


174


are placed in one setting, the one limit switch


100


is defined as the “closed limit switch” and the other


102


is defined as the “open limit switch.” When the door type selection switches


172


,


174


are placed in the other setting, the roles of the limit switches


100


and


102


are swapped. In other words, the “closed limit switch” becomes the “open limit switch” and the “closed limit switch” becomes the “open limit switch.”




For example, as shown in

FIG. 4

, when both switches


172


,


174


are set to the left, both the right and left limit switches


100


,


102


as shown in

FIG. 3

(and

FIGS. 11 and 14

) direct the motor control circuit


106


to stop the motor


82


(when either is tripped), and the left limit switch


100


directs (when tripped) the control panel


58


to indicate that the door


12


is closed. In contrast, when both switches


172


,


174


are set to the right, both the right and left limit switches


100


,


102


direct the motor control circuit


106


to stop the motor


82


(when either is tripped), and the right limit switch


102


directs (when tripped) the control panel


58


to indicate that the door


12


is closed. Hence, overall, the mechanism


10


is not generally “handed” in the sense that other door locking mechanisms are. While other door locking mechanisms provide that several parts must be replaced to use a right-handed mechanism with a left-handed door, and vice versa, a mechanism which is in accordance with an embodiment of the present invention provides that the mechanism


10


can be re-configured for the other type of door merely by switching one or more switches


172


,


174


. Of course, it is possible to combine the two door type selection switches


172


,


174


into a single switch. Regardless, any door type selection switch which is provided may be provided, for example, on the relay connection board


110


which was referred to above.




While both a rack and pinion mechanism (


134


,


88


) and a chain drive mechanism have been mentioned hereinabove, another embodiment of the present invention may provide that the motor


82


directly drives the lockhead member


28


. In such a case, the motor


82


may drive a cam surface which is engaged with an edge of the lockhead member


28


. While the rack and pinion and the chain drive embodiments provide that mechanism can both lock/unlock and open and close a door, this third embodiment would provide that the mechanism only locks or unlocks the door. Of course, in such an embodiment, it is preferred that the mechanism still provide a double deadlocking feature and still indicate on the control panel


58


when the door is deadlocked.




Regardless of which embodiment is employed, it is preferred that each be housed in a durable housing, such as a horizontal housing which is generally mounted on L-brackets. The housing may be formed from 7 gauge steel, and may include a hinged cover which is formed from 10 gauge steel. Preferably, all housing openings are baffled to deflect the insertion of any foreign objects. Preferably, the cover is attached to the housing with pinned, Torx® head machine screws. The release column


60


may include hard rubber bumpers which cushion the impact of the door


12


when it closes. The release column


60


may also house an intercom speaker. Still other features and alternatives would be recognized by one having ordinary skill in the art.




While embodiments of the present invention are shown and described, it is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the spirit and scope of the invention as defined by the appended claims. The invention is not intended to be limited by the foregoing disclosure.



Claims
  • 1. A door locking mechanism for double deadlocking a door, said door locking mechanism comprising: a lockhead member including a door stopping portion, said lockhead member moveable from a locked position wherein the door is double deadlocked and an unlocked position; a vertical locking mechanism coupled to the lockhead member, said vertical locking mechanism deadlocking said door when said lockhead member is in the locked position, said door stopping portion of said lockhead member also deadlocking said door when said lockhead member is in the locked position; a carriage assembly engaged with the door, said carriage assembly including at least one surface for engaging said door stopping portion and moving said lockhead member from the locked position to the unlocked position, wherein said vertical locking mechanism disengages said door when said lockhead member is in the unlocked position and said door stopping portion of said lockhead member also disengages said door when said lockhead member is in the unlocked position; and a motor driveably engaged with said carriage assembly, wherein movement of said carriage assembly causes the carriage assembly to engage the door stopping portion of the lockhead member and move the lockhead member to the unlocked position, further comprising a motor control circuit including a first limit switch for sensing said carriage assembly, a second limit switch for sensing said carriage assembly, and at least one indicating device for indicating a position of the door, wherein the first and second limit switches are in communication with the indicating device, wherein said motor control circuit further includes at least one switch which is operable to select which one of the first and second limit switches dictates what status is indicated by the indicating device when the door is in a given position.
  • 2. A door locking mechanism as recited in claim 1, further comprising a deadlock lever operatively associated with said lockhead member such that movement of said lockhead member causes movement of said deadlock lever, said deadlock lever including a vertical locking mechanism obstructing portion, said vertical locking mechanism obstructing portion generally aligning with said vertical locking mechanism when said lockhead member is in the locked position whereby said vertical locking mechanism is prevented from being manually disengaged from the door, said vertical locking mechanism obstructing portion generally dis-aligning with said vertical locking mechanism when said lockhead member is moved to the unlocked position thereby providing that said vertical locking mechanism disengages from the door upon the lockhead member moving to the unlocked position.
  • 3. A door locking mechanism as recited in claim 2, wherein said lockhead member comprises a first plate and said deadlock lever comprises a second plate, said lockhead member being generally keyed to said deadlock lever, said door stopping portion of said lockhead member being received in a slot in said second plate.
  • 4. A door locking mechanism as recited in claim 3, said door stopping portion of said lockhead member comprising a roller which is pinned to said first plate.
  • 5. A door locking mechanism as recited in claim 1, further comprising a mechanism plate having a channel defined thereon, wherein said lockhead member is slidable in said channel from the locked position to the unlocked position.
  • 6. A door locking mechanism as recited in claim 5, wherein said lockhead member comprises a first plate and said deadlock lever comprises a second plate, said lockhead member being generally keyed to said deadlock lever, said first plate having a first roller pinned thereto, said door stopping portion of said lockhead member comprising a second roller which is received in a slot in said second plate, said door locking mechanism further comprising a bar which is engageable with said first roller to move said lockhead member from the locked position to the unlocked position.
  • 7. A door locking mechanism as recited in claim 1, wherein said carriage assembly includes at least one of a geared rack and a chain section and said motor drives at least one of a pinion and a sprocket which is engaged with at least one of the geared rack and chain section of the carriage assembly.
  • 8. A door locking mechanism as recited in claim 1, wherein said carriage assembly includes a travel bar assembly which includes a plurality of rollers which are engaged with a guide member.
  • 9. A door locking mechanism as recited in claim 1, wherein said carriage assembly includes a driven portion which is engaged and is driveable by said motor, said driven portion engageable with said door stopping portion, wherein said carriage assembly includes a following portion comprising a travel bar assembly which includes a plurality of rollers which are engaged with a guide member, wherein said driven portion and said following portion are operatively engaged with each other to provide that said driven portion is moveable relative to said following portion for a length of travel of said driven portion wherein said driven portion engages said door stopping portion thereby causing said door stopping portion to move out of a direction of subsequent travel of said following portion which results upon further movement of said driven portion.
  • 10. A door locking mechanism as recited in claim 1, wherein both the first and second limit switches dictate the length of door travel, said motor control circuit including at least one switch which is operable to select the direction to which the door travels.
  • 11. A door locking mechanism as recited in claim 1, further comprising a deadlock lever operatively associated with said lockhead member such that movement of said lockhead member causes movement of said deadlock lever, said deadlock lever including a vertical locking mechanism obstructing portion, said vertical locking mechanism obstructing portion generally aligning with said vertical locking mechanism when said lockhead member is in the locked position whereby said vertical locking mechanism is prevented from being manually disengaged from the door, said vertical locking mechanism obstructing portion generally dis-aligning with said vertical locking mechanism when said lockhead member is moved to the unlocked position thereby providing that said vertical locking mechanism disengages from the door upon the lockhead member moving to the unlocked position; and a mechanism plate having a channel defined thereon, wherein said lockhead member is slidable in said channel from the locked position to the unlocked position.
  • 12. A door locking mechanism for deadlocking a door, said door locking mechanism comprising: a lockhead member including a door stopping portion; a carriage assembly engaged with the door, said carriage assembly including a driven portion and a following portion; a motor driveably engaged with the driven portion of the carriage assembly, said driven portion engaged with said following portion such that said driven portion is movable relative to the following portion for a first portion of a range of movement of the driven portion and said following portion is pulled by said driven portion for a second portion of the range of movement of the driven portion, said driven portion including a surface which engages said door stopping portion of said lockhead member during the first portion of the range of movement of the driven portion thereby moving said door stopping portion such that said following portion of said carriage assembly is pullable by said driven portion during the second portion of the range of movement of the driven portion, thereby moving the door, wherein said lockhead member comprises a plate and said door stopping portion comprises a roller pinned to said plate, further comprising a deadlock lever operatively associated with said lockhead member such that movement of said lockhead member causes movement of said deadlock lever, said deadlock lever including a vertical locking mechanism obstructing portion, said vertical locking mechanism obstructing portion generally aligning with said vertical locking mechanism when said lockhead member is in the locked position whereby said vertical locking mechanism is prevented from being manually disengaged from the door, said vertical locking mechanism obstructing portion generally dis-aligning with said vertical locking mechanism when said lockhead member is moved to the unlocked position thereby providing that said vertical locking mechanism disengages from the door upon the lockhead member moving to the unlocked position; and a mechanism plate having a channel defined thereon, wherein said lockhead member is slidable in said channel from the locked position to the unlocked position, wherein said deadlock lever is keyed to said mechanism plate, further comprising a motor control circuit including a first limit switch for sensing said carriage assembly, a second limit switch for sensing said carriage assembly, and at least one indicating device for indicating the position of the door, wherein the first and second limit switches are in communication with the indicating device, wherein said motor control circuit further includes at least one switch which is operable to select which one of the first and second limit switches dictates what status is indicated by the indicating device when the door is in a given position.
  • 13. A door locking mechanism for locking a door, said door locking mechanism comprising: a lockhead member including a door stopping portion, said lockhead member moveable from a locked position wherein the door is locked and an unlocked position; a vertical locking mechanism coupled to the lockhead member, said vertical locking mechanism locking said door when said lockhead member is in the locked position, said door stopping portion of said lockhead member also locking said door when said lockhead member is in the locked position; a carriage assembly engaged with the door, said carriage assembly including at least one surface for engaging said door stopping portion and moving said lockhead member from the locked position to the unlocked position, wherein said vertical locking mechanism disengages said door when said lockhead member is in the unlocked position and said door stopping portion of said lockhead member also disengages said door when said lockhead member is in the unlocked position; and a motor driveably engaged with said carriage assembly but not carried thereby, wherein movement of said carriage assembly causes the carriage assembly to engage the door stopping portion of the lockhead member and move the lockhead member to the unlocked position, further comprising a deadlock lever operatively associated with said door stopping portion of said lockhead member such that movement of said lockhead member causes movement of said deadlock lever, said deadlock lever including a vertical locking mechanism obstructing portion, said vertical locking mechanism obstructing portion generally aligning with said vertical locking mechanism when said lockhead member is in the locked position whereby said vertical locking mechanism is prevented from being manually disengaged from the door, said vertical locking mechanism obstructing portion generally dis-aligning with said vertical locking mechanism when said lockhead member is moved to the unlocked position thereby providing that said vertical locking mechanism disengages from the door upon the lockhead member moving to the unlocked position.
  • 14. A door locking mechanism as recited in claim 13, wherein said deadlock lever is separate from and not carried by said carriage member.
  • 15. A door locking mechanism as recited in claim 13, wherein said deadlock lever is at all times in contact with said lockhead member.
  • 16. A door locking mechanism as recited in claim 13, further comprising a mounting plate which is mountable at a height which is above a height of the door, wherein the lockhead member is carried by the mounting plate, further comprising a motor ultimately mounted to the mounting plate and driveably engaged with said carriage assembly.
  • 17. A door locking mechanism as recited in claim 16, wherein the deadlock lever is carried by the mounting plate.
  • 18. A door locking mechanism as recited in claim 13, wherein the door stopping portion of the lockhead member comprises a roller.
  • 19. A door locking mechanism as recited in claim 18, wherein said roller extends through a slot in said deadlock lever.
Parent Case Info

This patent claims benefit of a provisional Application No. 60/156,212, filed Sep. 27, 1999.

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Number Name Date Kind
4190985 Richards et al. Mar 1980 A
4621451 Bruehler Nov 1986 A
4641458 Pilcher et al. Feb 1987 A
4723373 Jump Feb 1988 A
4872284 Bentley Oct 1989 A
4897959 Worden Feb 1990 A
4982528 Michel Jan 1991 A
5241787 Norman Sep 1993 A
5299385 McConnell Apr 1994 A
5866999 Schmelzer et al. Feb 1999 A
Provisional Applications (1)
Number Date Country
60/156212 Sep 1999 US