# Patent

## Title
Utility cart with electronic lock cabinet

## Abstract

A utility cart includes a cabinet with a latch and strike lock, which is unlocked in the presence of a passive near field RFID key device and held open by a latch controller for sufficient time to allow the user to open the unlocked cabinet door. The latch is biased to its locking position, to which it returns when released by the controller. The latch includes a ramp surface which is engaged by the leading edge of the strike as the cabinet door is closed. In this way, the strike pushes the latch out of the way as it passes over the end of the latch, and the biased latch then returns to its locking position engaging a keeper in the strike as the keeper passes into position opposite the latch.

## Background
FIELD OF THE INVENTION
The present invention relates to the field of utility carts.
BACKGROUND OF THE INVENTION
Utility carts typically comprise a wheeled base, a handle, and a set of shelves and/or cabinet in which chemicals, cleaning supplies and other tools can be kept. The cabinets often include a lock which can be unlocked and relocked by means of a key carried by the user of the cart.
SUMMARY OF THE INVENTION
The utility cart of the present invention includes a cabinet with a latch and strike lock, which is unlocked in the presence of a passive near field RFID key device, and held open by a latch controller for sufficient time to allow the user to open the unlocked cabinet door. The latch is biased to its locking position, to which it returns when released by the controller. The latch includes a ramp surface which is engaged by the leading edge of the strike as the cabinet door is closed. In this way, the strike pushes the latch out of the way as it passes over the end of the latch, and the biased latch then returns to its locking position engaging a keeper in the strike as the keeper passes into position opposite the latch.
These and other objects, advantages and features of the invention will be more fully appreciated by reference to the written description of the preferred embodiments, the claims and the appended drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective view of the utility cart of the preferred embodiment;
FIG. 2 is a perspective view of the covered latch and lath controller housing;
FIG. 3 is a perspective view of the interior of the latch and controller housing and the housing cover, with the housing removed and with the door handle and strike shown in their locked position by engagement with said latch;
FIG. 4 is a view of the latch and controller housing and its contents, with the housing cover removed;
FIG. 5 is a perspective view of the side wall of the cart cabinet, showing the opening therein, which exposes the open interior of the latch and controller housing and its contents;
FIG. 6 is a plan view of the latch controller, door and strike mechanism, with the housing removed and without showing the cabinet;
FIG. 7 is a fragmentary plan view of the latch mechanism;
FIG. 8 is a fragmentary perspective view of the latch mechanism;
FIG. 9 is a control schematic:
FIG. 10 is a perspective view showing a near field RFID key card being positioned near the antenna of said latch controller; and
FIG. 11 is a perspective view of the cabinet door being opened.



DESCRIPTION OF THE PREFERRED EMBODIMENT
Table 1 below lists the components of the preferred embodiments. Utility cart 1 includes a wheeled platform 2 and a cabinet 3 having a hinged cabinet door 4 (FIG. 1). A handle and strike member 10 is secured to the edge of door 4 (FIGS. 1, 10). A housing 6 containing a latch 20, latch actuator 30, controller 40 and a battery 50 is secured to the inside of cabinet sidewall 3a, adjacent an opening 3b (FIGS. 3-5). A cover plate 5 is fitted to the sidewall of cabinet 3 to cover opening 3a, and to cover the open side of housing 6 (FIGS. 1, 2). Controller 40 comprises a micro controller board 41 operably attached to an antenna board 42 which is located adjacent opening 3b in sidewall 3a of cabinet 3 (FIGS. 4, 5), and is covered by cover plate 5 (FIGS. 1, 2). To open door 4 of cabinet 3, one places a near field RFID card 8 adjacent cover plate 5. This allows communication with antenna 42 which causes the micro controller board 41 to activate actuator 30, releasing latch 20 and holding it for sufficient time to allow a user to open door 4 using handle 10 as shown in FIGS. 10 and 11.







TABLE 1





Component Listing


















Cart
 1



Wheeled base
 2



Cabinet
 3



Cabinet door
 4



Cover plate
 5



Pin hole
 5a



Controller/latch housing
 6



Inside wall
 6a



Detent aperture
 6b



Slot opening
 6c



Antenna mounts
 6d



Cover plate mounts
 6e



Pivot mount peg
 6f



Fasteners
 7



RFID key card
 8



Handle/Strike
10



Handle flange
11



Handle mount
11



Spacer flange
13



Strike
14



Keeper
15



Latch
20



Pivot pin
21



Latch arm
22



Detent
23



Detent ramp
23a



Detent locking ramp
23b



Tail
24



Bias spring
25



Actuator
30



Actuator arm
31



Controller
40



microcontroller board
41



Antennae board
42



Led indicator
43



Battery
50










Handle and strike 10 is preferably bent from a piece of metal and comprises a handle flange 11 which a person engages to open door 4 (FIGS. 1, 3 & 11). Flange 11 extends at right angles from a flange 12 which is secured to the edge of cabinet door 4 (FIGS. 1, 6). Flange 13 extends from mounting flange 12 at right angles and is also secured to cabinet door 4 on the inside surface thereof (FIG. 6). Finally, strike flange 14 extends perpendicularly from flange 13 and includes a keeper opening 15 therein (FIGS. 3, 6).
Housing 6 is an open sided tray like housing, comprising a perimeter edge wall and an inside wall 6a. The various components contained in housing 6 are directly or indirectly mounted to inside wall 6a of housing 6 (FIG. 4). Corner bosses 6e facilitate the mounting of housing 6 to the sidewall 3a of cabinet 3, using fasteners 7 (FIGS. 4, 5). Housing 6 is secured to the inside of cabinet side wall 3a, such that the open side of housing 6 faces the opening 3b in cabinet side wall 3a (FIG. 4).
Latch 20 is pivotally mounted on pivot pin 21 which is fixedly mounted within housing 6, on peg 6f which projects from housing inside wall 6a (FIGS. 3, 8). Latch 20 includes a horizontal arm 22 which pivots about pivot pin 21, and includes a detent member 23 projecting from one end thereof for engagement with keeper aperture 15 (FIGS. 3, 6). Arm 22 extends from detent 23 past pivot pin 21 to a downwardly depending tail 24 (FIGS. 3, 6, 7 & 8).
Latch 20 is normally biased into its locking position by bias spring 26. Bias spring 25 coils around pivot pin 21 and includes an extending leg 25a, the end of which is seated in a groove 24a in the downwardly extending tail 24 of pivot arm 12 (FIGS. 3, 7 & 8). After wrapping around pivot pin 21, another extending leg 25b rests against the inside of inside wall 6a of housing 6, thereby biasing latch 20 such that its detent end 23 projects through an aperture 6b in inside wall 6a of housing 6 (FIG. 7). Referring to FIG. 8, it can be seen that during assembly, projecting leg 25b actually extends through a slot opening 6c in inside wall 6a of housing 6. During assembly, leg 25b is tucked down through slot opening 6c and is pushed to the side of slot 6c so that it engages the inside of inside wall 6a. When strike 14 is in its locking position, detent end 23 is also biased to extend into keeper opening 15, thereby locking cabinet door 4 (FIGS. 3, 6).
Latch actuator 30 is a servo motor which includes a pivotally moving arm 31. Arm 31 engages tail 24 of latch 20 pivots latch 20, such that detent 23 is pivoted out of keeper aperture 15 in strike plate 14, unlocking door 4. Controller 40 holds arm 31 in its unlocking position long enough for a user to open door 4, as shown in FIG. 11. Actuator 30 is then released, arm 31 retracts, and latch 20 is biased back into its locking position by bias spring 25.
However, door 4 will typically be open when latch 20 returns. To facilitate re-locking of door 4, detent 23 on latch 20 includes an outwardly facing ramp surface 23a, which when latch 22 is positioned in its locked position as shown in FIGS. 3 and 6, allows strike plate 14 to slide over ramp surface 23a as one is closing door 4, thereby pushing detent 23 away from strike plate 14 and allowing it to pass over the end of detent 23 and be biased back into position within keeper aperture 15 as shown in FIGS. 1 and 6. The inside surface 23b of detent 21 is also sloped so as to make an acute angle with respect to arm 22, thereby providing a secure catch of strike plate 14 and making, it very difficult for one to accidentally cause strike plate 14 to be slid over detent 23 when latch 20 is in its locking position.
Controller 40 comprises microcontroller 41 connected to antenna board 42. Antenna board 42 is mounted by suitable fasteners on bosses 6d extending from inside wall 6a (FIG. 4). When so mounted, antenna board 42 is positioned in front of opening 3b in cabinet side wall 3a (FIG. 4). This improves the ability of antenna board 42 to communicate with near field RFID card 8.
Battery 50 is mounted in housing 6, and can be serviced through a removable covered opening in inside wail 6a of housing 6, or by removing cover plate 5, creating access to battery 50 though opening 3b in cabinet side wall 3a (FIG. 4). Battery 50 is electrically connected to and provides power to microcontroller 41 (FIG. 9). Micro controller 41 provides power to an RFID controller subunit 41a, which provides power and instructions to antenna 42, and in turn receives information from antenna 42 which antenna 42 receives from an activated near field RFID key card (FIG. 9). Microcontroller 41 is also electrically connected to and provides instructions to a red/green bi-colored indicator led 43 (FIG. 9), which is visible through a clear lens in cover 5 (FIG. 2). Micro controller is electrically connected to and sends instructions to actuator 30 (FIG. 9).
RFID controller 41a instructs antenna 42 to emit a continuous or intermittent signal which will be picked up by a near field RFID card 8 placed in close proximity to antenna 42. If the signal is transmitted intermittently, it must stay “on” sufficiently long to be picked up by a near field RAID card 8 placed in proximity to antenna 42 (FIGS. 9, 10), and to power through induction to coil in card 8 a return coated signal from card 8. RFID card 8 is then powered through induction by the antenna signal, and responds to the antenna signal by sending a coded signal to RFID controller 41a through antenna 42. If the coded signal matches the coded information recorded in RFID controller 41a, microcontroller 41 causes the bi-colored LED light 43 to glow green (43a in FIG. 9), indicating that latch 22 will be unlocked and door 4 can be opened. If the signal from RFID card 8 does not match the code information in RFID controller 41a, microcontroller 41 causes bi-colored LED light 43 to glow red (43b in FIG. 9), indicating that latch 22 is not in its unlocked position and door 4 cannot be opened. When the RFID controller 41a senses a match with the RFID key card, micro controller 41 sends power to servo actuator 30, which rotates servo arm 31 and causes latch 22 to pivot into its unlocking position.
Microcomputer board 42 includes a delay function which holds servo arm 31 and latch 22 in its unlocked position long enough for the user to grasp handle flange 11 and open door 4 (FIG. 11). Preferably, the delay is from about 2 to 10 seconds, more preferably about 2-5 seconds, and most preferably about 3 seconds. The timer circuit then times out and bias spring 25 biases latch 22 back into its locked position, though with door 4 open so that detent 23a is not engaging the keeper in strike 14.
After completing his work, the user simply closes door 4 such that strike flange 14 slides over ramp 23a, pushing latch 22 out of the way, until keeper aperture 15 is located over the end of detent 23, at which point biasing spring 25 forces latch 22 back into its locking position with detent 23 extending through keeper aperture 15.
To accommodate loss of power caused by a dying or faulty battery, cover plate 5 is provided with a pin hole 5a (FIG. 2), which is aligned with the tail end 24 of latch arm 22. This allows a user to insert a slender rod and engage and push tail end 24 away, pivoting latch 22 into its opening position.
Of course, it is understood that the foregoing discloses preferred embodiments of the invention, and that various changes and alterations can be made without departing from the breadth and spirit thereof as set forth in the appended claims.

## Claims

1. A utility cart comprising: a wheeled base and a cabinet, said cabinet including a door which opens and closes to permit or prevent access to the interior of said cabinet; said cabinet including a latch moveable between a locking and unlocking position, said latch being biased to said locking position; said door including a strike having a keeper for receiving a portion of said latch to lock said door against opening; said cabinet including a controller for controlling said latch and causing said latch to move from said locking position to said unlocking position; said controller comprising an RFID controller and an antenna for transmitting an RFID signal; a passive RFID key device which responds to said RFID transmission; said controller causing said latch to move from said locking position to said unlocking position in response to receiving the correct information from said RFID key device, and said controller holding said latch in said unlocking position for sufficient time to allow a user to open the unlocked cabinet door; said controller releasing said latch after said sufficient time, whereby said latch is biased into the locking position of said latch; said latch including a ramp surface which is engaged by said strike as said cabinet door is closed, whereby said strike pushes said latch against the bias of said latch and out of the way as said strike passes over the engaged portion of said latch, and whereby said biased latch then returns to the locking position of said latch engaging said keeper in said strike as said keeper passes into position opposite said latch.

2. The utility cart of claim 1 in which said RFID controller and said RFID key device are near field RFID controllers and devices respectively.

3. The utility cart of claim 1 in which said sufficient time is from about 2 to 10 seconds.

4. The utility cart of claim 1 comprising said latch being pivotally mounted on a pivot and including a detent member projecting therefrom on one side of said pivot for engagement to said keeper, and a tail on the opposite side of said pivot; a latch actuator including a pivot arm for engaging said tail of said latch; said controller causing said latch to move from said locking position of said latch to said unlocking position by causing said actuator to rotate said pivot arm, to thereby rotate said latch from said locking position into said unlocking position.

5. The utility cart of claim 4 in which said latch is normally biased into said locking position of said latch by a bias spring coiled around said pivot and including one end of said spring engaging said latch and another end of said spring being fixed at a point other than on said latch.

6. The utility cart of claim 4 in which said latch, said latch actuator and said controller are housed in a housing secured to an inside wall of said cabinet, wherein said latch is in alignment with said strike as said door is closed.

7. The utility cart of claim 6 in which said housing includes an inside wall joined to a perimeter wall, and an open side; said inside wall including a detent aperture through which said detent projects when said latch is in said locking position; said hosing being positioned such that said keeper in said strike aligns with said detent aperture when said door of said cabinet is closed; said antenna of said controller being located at said open side of said housing; said cabinet inside wall to which said housing is secured having an aperture therein, which is aligned with said antenna when said housing is secured to said inside wall.

8. The utility cart of claim 7 which also includes a battery mounted in said housing and connected so as to provide power to said controller and said latch actuator.

9. The utility cart of claim 7 in which said cabinet wall aperture and said antenna are covered by a cover on the exterior side of said cabinet wall.

10. The utility cart of claim 9 which includes a bi-functional indicator which shows one condition when said RFID key device communicates the correct information to said controller, thus indicating that said door is unlocked, and shows another condition when said RFID key device communicates the incorrect information to said controller, thus indicating that said door remains locked; said bi-functional indicator being positioned to be visible through an indicator opening in said cover.

11. The utility cart of claim 4 in which said RFID controller and said RFID key device are near field RFID controllers and devices respectively.

12. The utility cart of claim 4 in which said sufficient time is from about 2 to 10 seconds.

13. The utility cart of claim 1 in which said latch, said latch actuator and said controller are housed in a housing secured to an inside wall of said cabinet, wherein said latch is in alignment with said strike as said door is closed.

14. The utility cart of claim 13 in which said housing includes an inside wall joined to a perimeter wall, and an open side; said antenna of said controller being located at said open side of said housing; said cabinet inside wall to which said housing is secured having an aperture therein, which is aligned with said antenna when said housing is secured to said inside wall.

15. The utility cart of claim 14 in which said cabinet wall aperture and said antenna are covered by a cover on the exterior side of said cabinet wall.

16. The utility cart of claim 15 which includes a bi-functional indicator which shows one condition when said RFID key device communicates the correct information to said controller, thus indicating that said door is unlocked, and -a shows another condition when said RFID key device communicates the incorrect information to said controller, thus indicating that said door remains locked; said bi-functional indicator being positioned to be visible through an indicator opening in said cover.

17. The utility cart of claim 1 which includes a bi-functional indicator which shows one condition when said RFID key device communicates the correct information to said controller, thus indicating that said door is unlocked, and -a shows another condition when said RFID key device communicates the incorrect information to said controller, thus indicating that said door remains locked.

18. The utility cart of claim 17 in which said latch, said latch actuator and said controller are housed in a housing secured to an inside wall of said cabinet, wherein said latch is in alignment with said strike as said door is closed.

19. The utility cart of claim 1 in which said strike is a component of a handle and strike member comprising: a handle flange which a person engages to open said cabinet door; said handle flange being joined to a mounting flange which is secured to the edge of said cabinet door; a second mounting flange extends from said mounting flange at right angles and is also secured to said cabinet door on the inside surface thereof; said strike comprising a strike flange extending perpendicularly from said second mounting flange, said keeper comprising a keeper opening in said strike flange.

20. The utility cart of claim 19 comprising said latch being pivotally mounted on a pivot and including a detent member projecting therefrom on one side of said pivot for engagement with said keeper, and a tail on the opposite side of said pivot; a latch actuator including a pivot arm for engaging said tail of said latch; said controller causing said latch to move from its said locking position to said unlocking position by causing said actuator to rotate said pivot arm, to thereby rotate said latch from said locking position into said unlocking position.