Abstract:
A vacuum actuated door latching assembly for use in combination with a door of a delivery vehicle. The latch assembly moves between locked and unlocked positions and includes a pneumatic actuator that drives the latch assembly between the locked and unlocked positions. Extending from the pneumatic actuator is a vacuum line that is adapted to be connected to a vacuum source such as the engine of the delivery vehicle. A control valve is disposed between the vacuum source and the pneumatic actuator for controlling the activation of the pneumatic actuator. A biasing device engages the door and biases the door towards and open position. Thus, when the latching assembly is actuated the door of the delivery vehicle is unlatched and the biasing device causes the door to assume the open position.

Description:
FIELD OF THE INVENTION 
     The present invention relates to delivery vehicles, and more particularly to an automatic door unlocking system for the vehicle. 
     BACKGROUND OF THE INVENTION 
     Delivery vehicles are widely used throughout the United States and the world. Typically these delivery vehicles have a small cab area and behind the cab area there is a load or cargo area. A bulkhead ordinarily separates the load or cargo area from the cab and typically a sliding door is placed in the bulkhead. When a driver of a delivery vehicle reaches a location where packages are to be delivered, the driver will bring the vehicle to a stop, open the sliding door with a key, retrieve the package, and upon leaving the vehicle, lock the door. This is a time consuming endeavor and it is repeated hundreds of times by the same driver over a relatively short period of time. 
     Therefore, there is and continues to be a need for an automatic door locking and unlocking system for a delivery vehicle that will enable the driver to quickly and easily retrieve and deliver packages without having to spend a great deal of time unlocking and locking the access door and which provides ample security for protecting the cargo within the vehicle. 
     SUMMARY OF THE INVENTION 
     The present invention entails a vacuum actuated automatic door latching assembly for use in a delivery vehicle. The latching assembly comprises a latch that is adapted to be associated with the access door of the delivery vehicle. The latch is movable between a locked position and an unlocked position. The system further comprises a pneumatic actuator operatively associated with the latch for causing the latch to move between the locked an unlocked position. A vacuum line is connected to the pneumatic actuator and extends therefrom and is adapted to connect to a vacuum source. A control valve is disposed between the vacuum source and the pneumatic actuator for controlling the actuation of the pneumatic actuator. Once actuated, the pneumatic actuator will operatively engage the latch and cause the latch to move from the locked position to the unlocked position. 
     In one embodiment, the latch assembly described above is provided with a biasing device for engaging the door and biasing the door towards an open position. Thus the biasing device will automatically push or urge the access door open. 
     The present invention also entails a method of unlocking an access door to a load or cargo department of a delivery vehicle. This method entails directing a vacuum from an engine of the delivery vehicle through a line to a pneumatic actuator that is operatively associated with a latch assembly that operates to lock and unlock the access door. The latch assembly includes a latch or locking lever that is movable between a locked position and an unlocked position. This method entails utilizing the vacuum to actuate the pneumatic actuator and when the pneumatic actuator is so actuated, the actuator engages the latch and moves the latch from the locked position to the unlocked position. This permits the access door to open. 
     In one particular embodiment, the method described above utilizes the vacuum of an engine that forms a part of the delivery vehicle. Here a vacuum line extends from the engine to the pneumatic actuator. A control valve is interposed in the vacuum line and simply by actuating the control valve, vacuum is directed through the line to the pneumatic actuator causing the same to be actuated. In the process the pneumatic actuator engages the latch and moves the latch to an unlocked position. 
     Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings, which are merely illustrative of such invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a perspective view of a delivery vehicle. 
         FIG. 2  is a fragmentary perspective view of a bulkhead and access door of a delivery vehicle shown with a door in a locked position. 
         FIG. 3  is a view similar to  FIG. 2 , but with the door being shown in an unlocked position. 
         FIG. 4  is an enlarged view of a latch assembly of the type shown in  FIGS. 2 and 3 . 
     
    
    
     DESCRIPTION OF THE INVENTION 
     With further reference to the drawings, a conventional delivery vehicle is shown therein and indicated generally by the numeral  10 . Vehicle  10  includes front and rear wheels  12 , a cab area  13 , and a load or cargo compartment  14 . The load or cargo compartment  14  is separated from the cab  13  by a transverse bulkhead  16 . As is appreciated, the area of the vehicle rearwardly of the bulkhead  16  comprises an area for receiving cargo such as packages, etc. A door  18  is formed in the bulkhead  16 . In this case, and in many typical cases, the door comprises a sliding door  18 . 
     Turning to  FIGS. 2-4 , there is provided a latch assembly indicated generally by the numeral  22 . Latch assembly  22  is mounted to the bulkhead  16  adjacent the sliding door  18 . As will be appreciated from subsequent portions of the disclosure, the latch assembly  22  is movable between locked and unlocked positions. In the locked position, the latch assembly  22  is operative to engage a receiver  20  mounted on the sliding door  18  so as to lock the sliding door and to close the access opening that is created when the sliding door  18  is open. Further, as will be appreciated, the latch assembly  22  may assume an unlocked position and in the unlocked position, the access door  18  can be opened in order to provide convenient access to the cargo compartment  14 . 
     The views illustrated in  FIGS. 2 and 3  show portions of the back of the bulkhead  16  and sliding door  18 . The opposite side of the bulkhead  16  and sliding door  18  faces the cab area of the vehicle. The latch assembly includes a lock  21  that is of a conventional design. Lock  21  includes a housing  24  having a back plate with an access opening  24 A formed therein. In  FIG. 2 , it is seen where the lock  21  and housing  24  are secured to the backside of the bulkhead  16 . On the front of the bulkhead, opposite the housing  24 , there is provided a key receiver for receiving a key that will lock and unlock the lock  21 . 
     Continuing to refer to the lock  21 , the same includes a pivotally mounted locking lever  26 . Locking lever  26  is pivotally mounted within the housing  24  and assumes a generally L-shape. Locking lever  26  includes a hook end portion  26 A and an actuating end portion  26 B. Locking lever  26 , as noted above, is pivotally mounted between these opposite end portions. 
     In  FIG. 4 , the locking lever  26  is shown in the locked position. Lock  21  is provided with a spring  23  that biases the locking lever to the locked position shown in  FIG. 4 . That is, the spring biases the locking lever counterclockwise to the position shown in  FIG. 4 . A stop is provided within the lock  21  to prevent the locking lever  26  from rotating further clockwise from the position that is shown in  FIG. 4 . As will be appreciated from subsequent portions of the disclosure, when the locking lever  26  assumes a position shown in  FIG. 4 , the hook end  26 A will extend into a receiver  20  that is fixed to the door  18  and projects therefrom. This will effectively lock door  18  to the bulkhead  16 . 
     Locking assembly  22  includes a pneumatic actuator indicated generally by the numeral  30 . Pneumatic actuator  30  is mounted adjacent the lock  21  and locking lever  26  thereof, as illustrated in  FIGS. 2 and 3 . The pneumatic actuator  30  includes a pneumatic cylinder  32  that is mounted on a bracket  34  that is in turn secured to the backside of bulkhead  16 . Pneumatic cylinder  32  is of a conventional design and includes a piston that reciprocates back and forth therein. Extending from the piston is a rod  36 . It is noted that the pneumatic actuator is mounted adjacent the lock  21  such that the rod  36  of the piston projects towards the housing  24  of the lock. Secured to the rod  36  of the piston projecting from the cylinder  32  is an arm  38 . Arm  38  is spaced such that it projects past the backside of the housing  26  and across a portion of the access opening  24 A formed in the housing  24 . Formed on the end portion of arm  38  is a projection or end portion  38 A that projects inwardly through the access opening  24 A. The projection  38 A extends into the plane of the actuating end portion  26 B of the locking lever  26 . This will enable the projection  38 A to engage the actuating end  26 B of the locking lever  26  during an unlocking operation. As will be appreciated from subsequent portions of this disclosure and as viewed in  FIG. 4 , when the latching assembly is actuated so as to unlock the door  18 , the arm  38  will move left to right and in the process the projection  38 A will engage the actuating end  26 B of the locking lever  26  and cause the locking lever to rotate clockwise as viewed in  FIG. 4 . This will cause the hook end  26 A of the locking lever  26  to disengage the receiver  20  secured to the door  18 , permitting the door  18  to open. 
     A vacuum line  40  extends from the pneumatic cylinder  32 . In the case of the present invention, the vacuum line  40  would extend to or be operatively connected to the engine of the vehicle  10 . Interconnected in the vacuum line  40  between the pneumatic cylinder  32  and the source of the vacuum is a control valve  42 . Control valve  42  is a conventional valve that in the case of the embodiment illustrated herein is normally closed. Valve  42  can be opened by simply pushing downwardly on the actuating button  42 A that forms a part of the valve. Once actuating button  42 A has been pushed down, the vacuum line  40  is open to the source of the vacuum and accordingly the vacuum can reach the pneumatic cylinder where it will effectively cause the piston to move from left to right within the cylinder  32  as viewed in  FIGS. 2 and 3 , thereby moving the locking lever  26  to the unlocked position. 
     The latching assembly  22  of the present invention further comprises a biasing member or assembly, indicated generally by the numeral  50 . Biasing member  50  is operative to bias the door  18  towards an open position while the door  18  is locked. Thus, as will be appreciated from the drawings and the disclosure to follow, once the latching assembly  22  assumes an unlocked position or mode, the biasing member  50  will cause the door  18  to be at least slightly opened. Viewing biasing member or assembly  50  in more detail, it is seen that the same comprises a mounting bracket  51  for mounting the biasing member  50  to the bulkhead  16  adjacent the door  18 . A sleeve  52  is mounted on the bracket  51 . A spring  54  is secured to a threaded bolt  56  that extends through the sleeve  52 . Threaded bolt  56  extends through a stop  58  mounted on the mounted bracket  51 . A pair of opposed threaded nuts  62  are secured on the threaded bolt  56  and can be tightened from each side against the stop  58  so as to retain the spring  54  in an appropriate position. 
     A stop  64  is secured to the door  18  and is generally aligned for engagement by the biasing assembly  50 . More particularly, by adjusting the nuts  62  the spring  54  can be appropriately adjusted such that when the door assumes a closed position, that the stop  64  is spaced with respect to the spring  54  such that the spring exerts a certain amount of opening force against the stop. As noted above, the degree of force exerted can be adjusted by selectively selecting the spring  54  and/or adjusting the position of the threaded bolt  56  with respect to the stop  58 . 
     In operation, the door  18  is normally locked. When locked, the locking lever  26  extends as shown in  FIG. 4  into engagement with the receiver  20 . It should be pointed out that at this time, the lock as viewed in  FIG. 4  can be unlocked through a conventional key that would be inserted into the lock  21  from the side of the bulkhead opposite of that shown in  FIGS. 2 and 3 . 
     In any event, once the driver of the vehicle  10  arrives at a stop where a package or other cargo is to be delivered, before the engine is shut down, the driver will actuate the control valve  42 . This will permit vacuum from the engine to be directed through the vacuum line  40  to the pneumatic cylinder  32 . This will cause the piston rod  36  to move left to right as viewed in  FIG. 4 . As the piston rod  36  moves left to right, the projection  38 A will engage the actuating end  26 B of the locking lever  26 . This will cause the locking lever  26  to rotate clockwise as viewed in  FIG. 4  to where the end  26 A of the locking lever will disengage the receiver  20 . Once locking lever  26  disengages the receiver  20 , then the biasing assembly  50  will push or urge the door  18  to at least a slightly open position. The driver will then shut the engine down. Because the locking lever  26  is biased to rotate downwardly to the locked position shown in  FIG. 4 , the actuating end  26 B will engage the projection  38 A of the arm  38  and cause the arm  38  and rod  36  to move right to left as viewed in  FIG. 4  until the locking lever is stopped at its normal locking position shown in  FIG. 4 . 
     Once the driver has removed the package from the cargo department  14 , the sliding door  18  can be moved towards the closed position. In this process, the receiver  20  will engage the locking end  26 A of the locking lever  26  and because of the angled shape of the hook end  26 A, the locking lever  26  will ride over the receiver  20  until the receiver has reached a certain point at which time the biasing action of the locking lever  26  will cause the same to rotate slightly counterclockwise into the locked position shown in  FIGS. 2 and 4 . 
     It is appreciated that the latch assembly  22  when locked, cannot be made to assume the unlocked position when the vehicle engine is shut down. This is because there is no source for the vacuum that is used to actuate the pneumatic actuator  30 . 
     From the foregoing discussion, it is appreciated that the present invention presents an efficient and cost effective way of automatically unlocking the access door for a deliver vehicle. By utilizing the system and method of the present invention, a great deal of time is saved at each delivery stop and security is maintained. 
     The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the scope and the essential characteristics of the invention. The present embodiments are therefore to be construed in all aspects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.