Electronic lock and key apparatus and method

Information

  • Patent Grant
  • 6483424
  • Patent Number
    6,483,424
  • Date Filed
    Monday, March 18, 1996
    28 years ago
  • Date Issued
    Tuesday, November 19, 2002
    21 years ago
  • Inventors
  • Examiners
    • Zimmerman; Brian
    Agents
    • Crozier; John H.
Abstract
In one preferred embodiment, an electronic key, including: a housing; unlocking apparatus extending from the housing, insertable in an electronic lock to unlock the electronic lock; and optical indicia reading apparatus disposed in the housing to read optical indicia. In another preferred embodiment, a lock system, including: at least two electronic cylinder locks; and a single electronic controller to which the at least two electronic cylinder locks are operatively attached, the electronic controller being adapted to monitor usage of the at least two electronic cylinder locks.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to lock systems generally and, more particularly, but not by way of limitation, to a novel, simplified, electronic lock system which is especially useful in monitoring use of the lock and eliminating unauthorized access to a locked device.




2. Background Art




Vendor enclosures (e.g., public telephones, vending machines, gaming machines, etc.) are generally divided into several compartments (e.g., a service compartment, a coin or money compartment, etc.) each with a separate lock. Access to each compartment is limited. For example, a service technician would not be allowed access to the coin area without special permission. In such situations, there are typically two keys provided, one for the money compartment and the other for the service area, for example. It is desirable to have a convenient method for auditing when the compartments have been accessed, what keys have been used, and in what sequence.




It is frequently necessary, in systems that employ locks, to collect location specific information in the field form media such as barcode labels affixed to the field device. Most collection system utilize a portable data collection device equipped with both an electronic key and a separate barcode wand. This arrangement results in the worker carrying a portable unit with two input devices connected to it, often making the unit difficult to carry and inefficient to use.




Accordingly, it is a principal object of the present invention to provide electronic key apparatus and method for multiple locked compartments that afford easy auditing of access to the compartments.




It is a further object of the invention to provide electronic key apparatus and method for collection systems that eliminates the need for having two input devices connected to a portable control unit.




Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures.




SUMMARY OF THE INVENTION




The present invention achieves the above objects, among others, by providing, in one preferred embodiment, an electronic key, comprising: a housing; unlocking means extending from said housing, insertable in an electronic lock to unlock said electronic lock; and optical indicia reading means disposed in said housing to read optical indicia. In another preferred embodiment, a lock system, comprising: at least two electronic cylinder locks; and a single electronic controller to which said at least two electronic cylinder locks are operatively attached, said electronic controller being adapted to monitor usage of said at least two electronic cylinder locks.











BRIEF DESCRIPTION OF THE DRAWING




Understanding of the present invention and the various aspects thereof will be facilitated by reference to the accompanying drawing figures, submitted for purposes of illustration only and not intended to define the scope of the invention, on which:





FIG. 1

is an exploded perspective view, partially cut-away, of an electronic lock constructed according to the the present invention.





FIG. 2

is a fragmentary rear elevational view showing the latching mechanism of the electronic lock.





FIGS. 3A-3D

are fragmentary rear elevational views showing the detection of unlocking of the lock.





FIG. 4

is a perspective view of a component of the electronic lock.





FIGS. 5A and 5B

comprise a block logic diagram showing operation of the lock.





FIG. 6

is an exploded isometric view of another embodiment of an electronic lock constructed useful in practicing the present invention.





FIG. 7

is a fragmentary isometric view of the lock of

FIG. 6

assembled and installed.





FIG. 8

is a schematic diagram illustrating the operation of the lock of FIG.


6


.





FIGS. 9A and 9B

are fragmentary top plan views, in cross-section, showing elements of the lock of

FIG. 6

in locked and unlock positions, respectively.





FIGS. 10A and 10B

are fragmentary front elevational views, in cross-section, showing elements of the lock of

FIG. 6

in locked and unlock positions, respectively.





FIG. 11

is a fragmentary, perspective view showing of a key constructed according to one embodiment of the present invention about to be inserted in a lock cylinder.





FIG. 12

is a perspective view showing the embodiment of

FIG. 11

being used to read a barcode label.





FIG. 13

is a perspective view showing a portion of a lock system constructed according to another embodiment of the present invention.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




Reference should now be made to the drawing figures, on which similar or identical elements are given consistent identifying numerals throughout the various figures thereof, and on which parenthetical references to figure numbers direct the reader to the view(s) on which the element(s) being described is (are) best seen, although the element(s) may be seen also on other views.





FIG. 1

illustrates an electronic lock useful in practicing the present invention, generally indicated by the reference numeral


10


, mounted, for example, to an existing cabinet door


12


.




Lock


10


includes a face cover


20


having an integral rearwardly extending hub


22


which hub fits into a complementarily shaped double-D opening


24


defined in cabinet door


12


to prevent the rotation of the face cover and hub relative to the cabinet door. A cylindrical drive hub


30


is inserted into and rotates within member


22


. Drive hub


30


has defined in the front portion thereof an opening (not shown) to accept therein a key or wrench (not shown) which may be the oval wrench described in the above-referenced application Ser. No. 08/395,417. Two drive pins


36


and


38


inserted into holes


40


and


42


defined in the rear face of drive hub


30


attach the drive hub to, in order, a first insulator


48


, a communication plate


50


, a second insulator


52


, and a lock hub


54


. Lock hub


54


is attached to a lock bar


60


by means of a screw


62


, the lock bar engaging a surface, such as surface


64


, for example, to prevent cabinet door


12


from being opened.




Lock


10


further includes a printed circuit board


70


having electronic circuitry, including a microprocessor and a non-volatile memory, mounted thereon and two contact wires


72


and


74


extending therefrom. An unlock solenoid


80


includes a lock plate


82


at the end thereof which engages a step


84


formed on lock hub


54


when lock


10


is in its locked position. A spring


86


biases lock plate


82


into the locked position when unlock solenoid


80


is unenergized.




All the components of lock


10


, except for lock bar


60


, are disposed in a housing


90


attached to the rear surface of cabinet door


12


and having a rear cover plate


92


, the components being secured together and attached to the rear surface of the cabinet door by means of two screws


94


and


96


extending through rear cover plate


92


holes


100


and


102


defined through the front of the housing and into the cabinet door. A spacer


106


extends between rear cover plate


92


and the front of housing


90


.




With reference also to

FIG. 2

, the action of unlock solenoid


80


is illustrated. Lock plate


82


is shown, in solid lines, engaging step


84


on lock hub


54


to prevent the rotation thereof. When unlock solenoid


80


is energized, lock plate


82


is withdrawn from engagement with step


84


, as shown in broken lines, and lock hub


54


is free to rotate counterclockwise as indicated by the arrow, thus disengaging lock bar


60


(

FIG. 1

) from surface


64


so that cabinet door


12


may be opened.




When lock


10


is subsequently locked by rotating lock hub


54


and the other rotating members clockwise, the lock hub is stopped at its home position by means of engagement of stop plate


82


with step


84


.




Lock


10


is arranged so that the same components may be employed for either 90-degree or 180-degree rotation of the rotating lock members. If 90-degree rotation is desired, lock bar


60


is used in the position shown, with a stop pin


120


extending forwardly of the lock bar and engaging an arcuate channel


122


defined in the rear surface of rear cover plate


92


. As lock bar


60


is rotated counterclockwise during unlocking of lock


10


, stop pin


120


will enter and move within channel


122


. When stop pin


120


engages the upper limit of channel


122


, further counterclockwise rotation of the lock bar and the other rotating components of lock


10


past 90 degrees will be prevented. If, on the other hand, 180-degree rotation is desired, lock bar


60


is removed from lock hub


54


, reversed, and reattached to the lock hub, with stop pin


120


facing rearwardly, thus permitting full rotation of the rotating members of lock


10


to the 180-degree position. The 180-degree position is determined by a rotation stop pin


110


, fixed in a opening


112


defined in rear cover plate


92


, engaging a channel


114


defined lock hub


54


, as is more clearly shown on FIG.


4


. As will be understood from

FIG. 4

, counterclockwise rotation of lock hub


54


will terminate when rotation stop pin


110


engages wall


116


of channel


114


. The selection of degree of rotation does not have to be made until lock


10


is being installed in the field.




Lock


10


is quite compact and can be easily retrofitted to installations where mechanical key locks were previously installed.




With continued reference to

FIG. 1

, two contact wires


72


and


74


are disposed so as to contact communication plate


50


for communication through a conductive post


130


on the communication plate, which conductive post electrically engages a contact pin on the key (not shown), as is described in the above-referenced application Ser. No. 08/395,417, for communication between the circuitry on board


70


and the key, as is also described in that application. The use of two contact wires


72


and


74


is used in the present invention to determine when lock


10


is in an unlocked position.

FIG. 3A

illustrates the position of communication plate


50


when lock


10


is in the locked position. Here, contact wires


72


and


74


complete and electrical path between board


70


and communication plate


50


. When unlocking begins and the rotating components of lock


10


have been rotated about 30 degrees counterclockwise, as is shown on

FIG. 3B

, the electrical path is broken, since contact wire


74


no longer contacts communication plate


50


, thus indicating an unlocked, or unlocking, condition.

FIGS. 3C and 3D

illustrate that no communication signal is received on contact wire


74


in either the 90-degree or 180 -degree unlock positions. At all times, the communication signal is transmitted on contact wire


72


.




Reference should now be made to

FIGS. 5A and 5B

for an understanding of a method of monitoring use of lock


10


.




Three keys are provided: a master key, an audit key, and a service key.




The master key is used to write a password too the memory of lock


10


or to change a previously written password. At step


200


, the master key is inserted in lock


10


, power is applied to the lock at step


202


, the lock responds with a request for key status at step


204


and, at step


206


, information is exchanged and an unlock command given by the key to the lock, all similar to the description in detail in application Ser. No. 08/395,417.




At step


208


, lock


10


determines if the key is a valid master key. If yes, the new password is written to the non-volatile memory in lock


10


, at step


210


, and, at step


212


, time-stamped positive acknowledgment is transmitted to the key.




If step


208


determines that the key is not a valid master key, that is, it is an audit key, a service key, or an unauthorized key, step


214


determines if the password given by the key is valid. If the password is not valid, step


216


records the number of password attempts in the memory of lock


10


and step


218


determines if the number of attempts has exceeded five. If the number of attempts has exceeded


5


, step


220


terminates lock responses. If the number of attempts has not exceeded five, then the procedure returns to step


204


. Permitting five attempts at access filters out errors due to noise, incorrect inputting of the user's PIN, and like events.




If step


214


determines that the password is valid, step


230


clears from memory the number of prior attempts with this key. Step


232


then determines if data is requested. If data is requested, that signifies that this key is an audit key and step


234


records the fact in memory. Then the data in memory as to who unlocked lock


10


, when the lock was unlocked, and for how long the lock was unlocked is transmitted to the key at step


236


and step


238


transmits a transaction completion status.




If step


232


determines that data is not requested, that signifies that the key is a service key and step


250


records in memory the key number, the date, the time, and the PIN of the user. Step


252


transmits a ready to unlock signal, solenoid


80


(

FIG. 1

) is activated at step


254


, and an unlock timer is started at step


256


. Step


258


continuously senses whether there is an unlocked condition and if it is not and step


260


determines that the unlock timer has not yet reached timeout, step


258


continues to look for unlock. If timeout is reached before unlock, the unlocking procedure is aborted and step


262


requires that the unlocking procedure restart.




When step


258


senses that lock


10


is unlocked (FIG.


3


B), the transaction is noted in memory at step


270


and an unlocked timer is started at


272


. Step


274


continuously detects if lock


10


is locked and, if not, the unlocked timer is periodically decremented at step


276


. If unlocked timer timeout is not found at step


278


, the unlocked timer continues to be decremented until timeout. Then, memory is updated at step


270


and the procedure reiterated until lock


10


is locked. This particular procedure is employed to minimize the amount of memory used. A clock signal may be received from the key f or use by the unlock and unlocked timers. When step


274


determines that lock


10


is locked, step


280


advises the microprocessor to expect loss of power.




When the electronic lock is applied to vending machines, for example, it is desirable that the locking/unlocking portion of the lock have a housing which is a ¾-inch diameter DD cylinder lock barrel, the de facto standard in the vending machine industry. This is accomplished by separating the control portion of the lock from the mechanical/electromechanical elements of the lock and reconfiguring the latter elements, as is described in detail below. Consequently, the latter elements can be inserted directly into an existing ¾-inch diameter, 1.9-inch long, DD cylinder lock barrel, with only minor modifications to the cylinder lock barrel.





FIG. 6

illustrates an embodiment of the electronic lock described immediately above, also useful in practicing the present invention, and generally indicated by the reference numeral


300


. Lock


300


has elements similar in function to a number of those of lock


10


(

FIG. 1

) and includes a housing


302


which may be the barrel of a conventional ¾-inch diameter, 1.9-inch long, DD cylinder lock. Elements of lock


300


which are inserted into housing


302


through the proximal end thereof are, in order: a tamper ring


304


, a retainer


306


, a front shaft


308


, a front insulator


310


, a communication commutator


312


, a middle insulator


314


, a solenoid commutator


316


, a rear insulator


318


having a channel


319


defined therein into which channel the solenoid commutator fits, a solenoid housing


320


, a solenoid


322


, a solenoid return spring


324


, a solenoid washer


326


, a solenoid plunger assembly having a rearwardly facing bar


330


disposed orthogonally to the major axis of housing


302


, and a rear shaft


332


having defined therein a slot


334


disposed orthogonally to the major axis of housing


302


and dimensioned to accept therein bar


330


.




Screws


340


secure solenoid


322


to solenoid housing


320


and pins


342


extending rearwardly from from shaft


308


secure elements


310


,


312


,


314


,


316


, and


318


to solenoid housing


320


for common rotation of elements


304


-


328


. All elements


308


-


328


, generally indicated by the reference numeral


340


, fit within retainer


306


, with the rear face of the front shaft engaging the front face of rear shaft


332


, but with bar


332


extending from the rear of retainer


306


as is described in detail below. An assembly pin


350


is insertable through housing


302


into retainer


306


to secure the retainer against rotation within the housing.




A key or wrench (not shown) is insertable through tamper ring


304


, into retainer


306


, and into a recess in front shaft


308


. In this embodiment, if unlocking of lock


300


is not authorized, the key or wrench will simply rotate elements


308


-


328


, without the breaking of any element(s) within the lock. A set screw


352


, a detent spring


354


, and a detent ball


356


are inserted into a threaded opening


358


defined through the wall of housing


302


such that the detent ball releasably engages a recess


360


defined in the outer periphery of front shaft


308


to provide a palpable “home” position for rotating elements


340


of lock


300


.




Rear shaft


332


has a threaded DD portion


370


extending rearwardly thereof, which DD portion extends through a suitably dimensioned opening


371


in the rear wall of housing


302


for attachment of a lock bar


372


to the DD portion by means of a nut


374


and a lock washer


376


. A rotating washer


378


disposed on DD portion


370


has flanges


390


and


392


extending from the periphery thereof, which flanges engage a stop


394


to terminate locking and unlocking rotation as lock


300


is locked or unlocked. Rotating washer


378


is reversible so that either 90-degree or 180-degree rotation of rotating elements


340


may be selected. A vertical slot


396


is defined in the rear wall of housing


302


extending across opening


371


.




A printed circuit board


400


is attached to a flat side of housing


302


by means of a screw


402


or other suitable attachment means, with wipers


404


,


406


, and


408


extending through an opening (not shown) defined through the wall of housing


302


. Wiper


404


slidingly engages communication commutator


312


, wiper


406


slidingly engages solenoid commutator


316


, and wiper


408


is a ground lead which slidingly engages solenoid housing


320


. Leads


420


connect printed circuit board


400


through connector


422


to a controller


424


, which controller is located remotely from housing


302


.





FIG. 7

illustrates housing


302


mounted in a panel


430


by means of a nut


432


. Panel


430


may be assumed to be part of a vending machine or a similar device. It can be seen that the electromechanical elements of lock


300


consume no more volume than a conventional key-operated cylinder lock and, were it not for printed circuit board


400


and leads


420


, the lock shown on

FIG. 7

would appear to be a conventional key-operated cylinder lock.




In use, and with reference also to

FIG. 8

, the end of a key or wrench, generally indicated by the reference numeral


440


, is inserted into front shaft


308


and a contact


442


in the key engages communication commutator


312


. Communication protocol similar to that shown on

FIGS. 5A and 5B

is now followed and, if unlocking is authorized, step


254


(

FIG. 5B

) causes solenoid


322


to be energized which causes bar


330


extending from the rear end of retainer


306


to engage both slot


334


in rear shaft


332


and vertically aligned cutouts


398


(only the upper cutout visible on

FIG. 6

) defined in the rear face of solenoid housing


320


. Then, any rotation of the key or wrench will rotate lock bar


372


(

FIG. 6

) from a locked position to an unlocked position.





FIGS. 9A

,


9


B,


10


A, and


10


B illustrate in more detail the operation of lock


300


. The elements shown on these figures have been separated slightly from their normal relative positions for greater clarity.





FIG. 9A

shows lock


300


in locked position. In the locked position, with solenoid


322


(

FIG. 6

) de-energized, solenoid spring


324


(

FIG. 6

) has driven bar


330


(

FIGS. 9A and 10A

) rearwardly, so that the bar engages both slot


334


in rear shaft


332


and channel


396


in the inside face of the rear wall of housing


302


, thus preventing lock bar


372


from being rotated. On the other hand, rotating elements


340


(

FIG. 9A

) are free to rotate, as described above, without breaking any internal components of lock


300


.




When solenoid


322


(

FIG. 6

) is energized, bar


330


is drawn forewardly, as shown on

FIG. 9B

, so that the bar engages slot


334


in rear shaft


332


and cutouts


398


in the rear face of solenoid housing


320


. Now, rotation of rotating elements


340


by means of a key or wrench (not shown) inserted in front shaft


308


(

FIG. 10B

) and turned will permit rotation of lock bar


372


(

FIG. 6

) to an unlocked position.




As will be understood from

FIG. 6

, once rotating elements


340


have been rotated about 20 degrees, wiper


406


will lose contact with solenoid commutator


316


which causes the de-energization of solenoid


322


and solenoid spring


324


will attempt to drive bar


330


rearwardly in housing


306


. Such is prevented, however, as will be understood with reference to

FIGS. 10A and 10B

.

FIG. 10A

shows bar engaging channel


396


, as is seen also on FIG.


9


A. When, however, bar


330


is withdrawn from channel


396


(

FIG. 9A

) and rotated (FIG.


10


B), it can no longer engage slot


396


and de-energization of solenoid


322


will simply only permit the end face of the bar to slide around the inner surface of the end wall of housing


306


. The opposite ends of bar


330


and channel


396


are asymmetrical with respect to the central axis of housing


306


, so that the bar cannot re-engage the channel if the bar is rotated 180 degrees.




De-energization of solenoid


322


, as described above, conserves power while lock


300


is in the unlocked position and the absence of current flow to the solenoid provides an indication to controller


424


that the lock is in an unlocked position.





FIG. 11

illustrates an electronic key constructed according to one embodiment of the present invention, generally indicated by the reference numeral


500


. Electronic key


500


includes a body


502


having a cable


504


extending from a first end thereof, the cable being attached, for example, to a portable control unit (not shown). Key


500


also includes an unlocking portion


506


extending from the side of the key and insertable in a lock cylinder


508


which may be part of the lock mechanism described above with reference to

FIGS. 6-8

, although the lock cylinder may, instead, be part of another type of lock mechanism. Disposed at a second end of key


500


is the optical sensing portion


520


of a barcode reading head (not shown) disposed in the key.





FIG. 12

illustrates electronic key


500


being used to read a barcode


530


disposed on a container


532


, which may be assumed to be the cash box of a public telephone, for example, by moving optical sensing portion


520


across the barcode. Barcode


530


is read in the conventional manner and electrical signals representative of the information in the barcode are transmitted to the portable unit (not shown) for later use.




This arrangement eliminates the necessity of having two input devices connected to the portable unit and is easy to carry and efficient to use.





FIG. 13

illustrates a system for a lock mechanism constructed according to another embodiment of the present invention, generally indicated by the reference numeral


550


. System


550


includes two electronic cylinder locks


552


and


554


attached, respectively, by cables


556


and


558


to a controller


560


. Elements


552


,


554


, and


560


may be part of an electronic lock system similar to that described above with reference to FIG.


6


.




According to the present invention one of electronic cylinder locks


552


and


554


is installed in a service compartment, while the other of the locks is installed in a money compartment, for example. Each of electronic cylinder locks


552


and


554


is associated with a unique identification number stored within the controller


560


. When an electronic key, such as key


500


(FIG.


11


), for example, is inserted in an electronic cylinder lock, controller


560


will, after the necessary security/identification measures are taken, report the identification number associated with the cylinder. Since controller


560


is common to both electronic cylinder locks


552


and


554


, it is possible to maintain an audit trail of which keys have been used to access the compartments, at what times, and in what sequence.




If a collector has successfully opened the coin compartment and needs to gain access to the service areas, it is possible for controller


560


to allow access to the service area by the same electronic key within a predetermined length of time. After that length of time, controller


560


would not allow access to the service compartment.




It will thus be seen that the objects set forth above, among those elucidated in, or made apparent from, the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown on the accompanying drawing figures shall be interpreted as illustrative only and not in a limiting sense.




It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.



Claims
  • 1. An electronic key, comprising:(a) a housing; (b) unlocking means extending from said housing, said unlocking means being insertable in an electronic lock to unlock said electronic lock; and (c) optical indicia reading means disposed in said housing to read optical indicia associated with said electronic lock for storage of electrical signals representative of information in said optical indicia for later use.
  • 2. A method of unlocking an electronic lock and reading optical indicia, comprising:(a) providing integrated electronic key means and optical indicia reading means; (b) unlocking an electronic lock with said electronic key means; and (c) reading optical indicia with said optical indicia reading means and storing electrical electrical signals representative of information in said optical indicia for later use.
  • 3. A lock system, comprising:(a) at least two electronic cylinder locks unlockable by key means; and (b) an electronic controller to which said at least two electronic cylinder locks are operatively attached, said electronic controller being adapted to monitor usage of said at least two electronic cylinder locks and to make a record of at least which said key means have been used to unlock said at least two locks electronic cylinder locks and at what times and in what sequence said at least two electronic cylinder locks have been unlocked.
  • 4. A lock system, as defined in claim 3, wherein: said electronic controller is further adapted to permit a second one of said at least two electronic cylinder locks to be unlocked within a predetermined period of time after a first one of said at least two electronic cylinder locks has been unlocked and to prevent said second one of said at least two electronic cylinder locks from being unlocked after said predetermined period of time has expired.
  • 5. A lock system, as defined in claim 3, wherein: a first one of said electronic cylinder locks is installed in a money compartment of a device and a second one of said electronic cylinder locks is installed in a service compartment of said device.
  • 6. A method of using a lock system, comprising:(a) providing at least two electronic cylinder locks unlockable by key means; (b) providing an electronic controller to which said at least two electronic cylinder locks are operatively attached, said electronic controller being adapted to monitor usage of said at least two electronic cylinder locks; and (c) using said electronic controller to make a record of at least which said key means have been used to unlock said at least two electronic cylinder locks and at what times and in what sequence said at least two electronic cylinder locks have been unlocked.
  • 7. A method of using a lock system, as defined in claim 6, further comprising: using said electronic controller to permit a second one of said at least two electronic cylinder locks to be unlocked within a predetermined period of time after a first one of said at least two electronic cylinder locks has been unlocked and preventing said second one of said at least two electronic cylinder locks from being unlocked after said predetermined period of time has expired.
  • 8. A method of using a lock system, as defined in claim 6, further comprising: installing a first one of said electronic cylinder locks in a money compartment of a device and installing a second one of said electronic cylinder locks in a service compartment of said device.
CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of application Ser. No. 08/574,276, filed Dec. 18, 1995 now U.S. Pat. No. 5,791,177, which is a continuation-in-part of application Ser. No. 08/510,486, filed Aug. 2, 1995 now U.S. Pat. No. 5,816,083, which is a continuation-in-part of application Ser. No. 08/395,417, filed Feb. 27, 1995 now abandoned, which is a continuation-in-part of application Ser. No. 07/985,840, filed Dec. 3, 1992, abandoned, which is a continuation-in-part of application Ser. No. 07/921,418, filed Jul. 27, 1992, abandoned, which is a continuation-in-part of application Ser. No. 07/780,155, filed Oct. 21, 1991, abandoned, the disclosures of which applications are incorporated by reference hereinto.

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Number Name Date Kind
3812403 Gartner May 1974 A
4509093 Stellberger Apr 1985 A
4789859 Clarkson Dec 1988 A
4829296 Clark May 1989 A
4833465 Abend May 1989 A
4932228 Eisermann Jun 1990 A
4967305 Murrer Oct 1990 A
5140317 Hyatt Aug 1992 A
5233658 Bianco Aug 1993 A
5298725 Fischer Mar 1994 A
5628216 Qureshi May 1997 A
Continuation in Parts (6)
Number Date Country
Parent 08/574276 Dec 1995 US
Child 08/617344 US
Parent 08/510486 Aug 1995 US
Child 08/574276 US
Parent 08/395417 Feb 1995 US
Child 08/510486 US
Parent 07/985840 Dec 1992 US
Child 08/395417 US
Parent 07/921418 Jul 1992 US
Child 07/985840 US
Parent 07/780155 Oct 1991 US
Child 07/921418 US