Utility cart with electronic lock cabinet

The present invention relates to the field of utility carts.

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.

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.

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.

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 3 a , adjacent an opening 3 b ( FIGS. 3-5 ). A cover plate 5 is fitted to the sidewall of cabinet 3 to cover opening 3 a , 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 3 b in sidewall 3 a 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 .

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 6 a . The various components contained in housing 6 are directly or indirectly mounted to inside wall 6 a of housing 6 ( FIG. 4 ). Corner bosses 6 e facilitate the mounting of housing 6 to the sidewall 3 a of cabinet 3 , using fasteners 7 ( FIGS. 4, 5 ). Housing 6 is secured to the inside of cabinet side wall 3 a , such that the open side of housing 6 faces the opening 3 b in cabinet side wall 3 a ( FIG. 4 ).

Latch 20 is pivotally mounted on pivot pin 21 which is fixedly mounted within housing 6 , on peg 6 f which projects from housing inside wall 6 a ( 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 25 a , the end of which is seated in a groove 24 a in the downwardly extending tail 24 of pivot arm 12 ( FIGS. 3, 7 & 8 ). After wrapping around pivot pin 21 , another extending leg 25 b rests against the inside of inside wall 6 a of housing 6 , thereby biasing latch 20 such that its detent end 23 projects through an aperture 6 b in inside wall 6 a of housing 6 ( FIG. 7 ). Referring to FIG. 8 , it can be seen that during assembly, projecting leg 25 b actually extends through a slot opening 6 c in inside wall 6 a of housing 6 . During assembly, leg 25 b is tucked down through slot opening 6 c and is pushed to the side of slot 6 c so that it engages the inside of inside wall 6 a . 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 23 a , 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 23 a 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 23 b 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 6 d extending from inside wall 6 a ( FIG. 4 ). When so mounted, antenna board 42 is positioned in front of opening 3 b in cabinet side wall 3 a ( 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 6 a of housing 6 , or by removing cover plate 5 , creating access to battery 50 though opening 3 b in cabinet side wall 3 a ( 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 41 a , 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 41 a 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 41 a through antenna 42 . If the coded signal matches the coded information recorded in RFID controller 41 a , microcontroller 41 causes the bi-colored LED light 43 to glow green ( 43 a 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 41 a , microcontroller 41 causes bi-colored LED light 43 to glow red ( 43 b in FIG. 9 ), indicating that latch 22 is not in its unlocked position and door 4 cannot be opened. When the RFID controller 41 a 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 23 a 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 23 a , 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 5 a ( 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.