Abstract:
A key fob for use in a remote keyless entry system of a vehicle includes a transmitter housing having at least one user operable button thereon indicative of remote keyless entry functions associated with the vehicle for transmitting function requests when the user operable buttons are depressed. A cover is retained on the transmitter housing and is slidably movable between an open position exposing the buttons and a closed position wherein the buttons are covered by the cover. Compression springs are coupled between the transmitter housing and the cover such that the springs urge the cover toward the open position, while a catch mechanism selectively and releasably secures the cover in the closed position against the bias of the springs.

Description:
BACKGROUND OF INVENTION  
       [0001]     The present invention relates to remote keyless entry systems for vehicles, and in particular to a key fob of a remote keyless entry system.  
         [0002]     Remote keyless entry (RKE) systems for vehicles enjoy wide use today, with RKE systems adding additional functions over and above the more conventional lock/unlock, trunk release and alarm functions. Such functions may include, for example, power door open/close and remote engine start. Typically, the conventional key fob transmits a vehicle function request whenever a button is pressed, whether inadvertent or not.  
         [0003]     In addition, some RKE systems employ a passive key fob where certain vehicle functions are performed based on, for example, the proximity and direction of movement of the key fob relative to the vehicle, rather than only reacting to the actuation of a button. While most functions are performed on these passive devices without the need to press a button, there may be buttons on them for the infrequent occasion when the user wishes to activate a vehicle function outside of the normal passive activation parameters. But again, inadvertent pressing of a button can cause a vehicle function to be performed even when the operator does not wish it to be.  
         [0004]     For some, a RKE function being performed when a button is inadvertently pressed is a significant annoyance. For example, when a key fob is in ones pocket or purse, an alarm or trunk release button may be inadvertently pressed, causing the key fob to transmit the requested vehicle function even if not desired by the one carrying the key fob. One may then have to pull out the key fob and press the button again or go over to the vehicle to counteract the inadvertent vehicle function performed.  
         [0005]     Thus, it is desirable to provide a way to limit the potential for inadvertently actuating the buttons on a key fob while still allowing for quick and easy access to the buttons when desired by the user.  
       SUMMARY OF THE INVENTION  
       [0006]     An embodiment of the present invention contemplates a key fob for use in a remote keyless entry system of a vehicle. The key fob may include a transmitter housing having one or more user operable buttons thereon indicative of a remote keyless entry function associated with the vehicle for transmitting a function request when the user operable button is depressed. The key fob may also include a cover retained on the transmitter housing and slidably movable between an open position exposing the one or more buttons and a closed position wherein the one or more buttons are covered by the cover. A biaser is coupled between the transmitter housing and the cover such that the biaser urges the cover toward the open position, and a catch mechanism selectively and releasably secures the cover in the closed position against the bias of the biaser.  
         [0007]     An advantage of an embodiment of the present invention is that the key fob includes a cover for protecting user operable buttons from inadvertent actuation, while also providing a simple, convenient, automatic cover release for quick and easy access to the buttons when desired.  
         [0008]     A further advantage of an embodiment of the present invention is that the quick and easy access to the user operable buttons on the key fob are provided while still retaining the cover to the transmitter housing at all times, thus avoiding the potential for the cover to become separated from the housing and lost. Moreover, once the user no longer needs access to the buttons, the cover is easily moved to and retained in its closed position until the next time the user wishes to access the buttons.  
         [0009]     An additional advantage of an embodiment of the present invention is that the catch mechanism, for holding the cover in its closed position, the automatic release, for biasing the cover to its open position, and the stop, for retaining the cover to the housing, are all relatively inexpensive to fabricate and assemble, thus minimizing the cost of the key fob.  
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0010]      FIG. 1  is a schematic front view of a key fob, with a cover shown in a closed position, in accordance with an embodiment of the present invention.  
         [0011]      FIG. 2  is a schematic front view similar to  FIG. 1 , but with the cover shown in its open position.  
         [0012]      FIG. 3  is a schematic, partial section, side view of the key fob of  FIG. 1 .  
         [0013]      FIG. 4  is a schematic front view similar to  FIG. 1 , but with the cover not shown.  
         [0014]      FIG. 5  is a cross section view of the cover, taken along line  5 - 5  in  FIG. 3 .  
         [0015]      FIG. 6  is a schematic front view similar to  FIG. 2 , but illustrating a second embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0016]      FIGS. 1-5  illustrate a portion of a remote keyless entry (RKE) system, indicated generally at  20 , employed with a vehicle (not shown). A base or vehicle mounted portion (not shown) of the RKE system  20  may include a receiver or transceiver (not shown) and a controller (not shown) that may be comprised of various combinations of hardware and software, as is known to those skilled in the art. The controller may be in communication with systems that carry out the desired RKE functions, such as a door lock/unlock actuator (not shown), a vehicle horn and headlights (not shown), an engine ignition system (not shown), a door actuator (not shown) and/or a trunk release mechanism (not shown). These systems will not be described in any detail since they are known to those skilled in the art.  
         [0017]     The RKE system  20  also includes a key fob  22 . The term “key fob” as used herein includes both a conventional key fob—where a signal is only transmitted to the vehicle when a button is pressed—as well as a passive remote keyless entry, remote start, keyless ignition, etc. type transmitter (also called passive remote function actuator)—where certain functions may be performed without any user input based on, for example, the proximity and motion of the device relative to the vehicle. For the latter type of key fob this invention may be particularly advantageous since the user buttons on the key fob may be rarely used.  
         [0018]     The key fob  22  has a transmitter housing  24 . Within the transmitter housing  24 , the key fob  22  may include a fob controller (not shown), powered by a battery (not shown), and a transmitter (not shown), capable of transmitting a radio frequency (RF) signal that can be received by the receiver in the vehicle. The transmitter of course may be a transceiver if the RKE system  20  includes two-way communication, and may transmit the signal by wireless means other than by RF transmission, if so desired. The details of the fob controller, transmitter and other electronic circuitry of the key fob  22  will not be discussed in detail herein since they are known to those skilled in the art.  
         [0019]     The transmitter housing  24  has a front side  26  and a back side  28 , and also has a recessed portion  30  that has smaller dimensions than a main portion  31 . On the front side  26  of the main portion  31  is a first user release location  46 , with the general size and position shown in phantom in  FIGS. 1-4 . On the back side  28  of the main portion  31  is a second user release location  48 , with the general size and position shown in phantom in  FIG. 3 . The user release locations  46 ,  48  are located generally in the middle of the front and back sides  26 ,  28 , respectively, and adjacent to the recessed portion  30 .  
         [0020]     On the front side  26 , in the recessed portion  30  of the housing  24 , first  32 , second  34 , and third  36  user operable buttons are located. The vehicle functions associated with these buttons  32 ,  34 ,  36 , may include, for example, door lock, door unlock, trunk release, engine start, door open, door close, alarm, etc. as is desired for the particular vehicle and RKE system  20 . The operation of these vehicle functions will not be discussed as they are known to those skilled in the art. This recessed portion  30  may also have a light emitting diode (LED)  37  located therein that may be activated, for example, to indicate a particular function is being performed, to indicate a low battery condition, etc.  
         [0021]     Also located in and extending outward from the recessed portion  30  of the housing  24  are a lock rib  38  and a stop pin  40 . The lock rib  38  extends widthwise across the recessed portion  30  adjacent to the main portion  31  of the housing  24 . The stop pin  40  is positioned so that it will be located under and in contact with a cover  50 , whether the cover  50  is in its closed or open position. The recessed portion  30  of the housing  24  also includes a pair of spring retention recesses  42 , within which are mounted a pair of compression springs  44 . While two springs  44  are illustrated, the key fob  22  may incorporate only one spring  44  and one spring retention recess  42  instead, if so desired. Also, other means of providing a biasing force similar to the springs may be employed instead of the springs, if so desired.  
         [0022]     The cover  50  of the key fob  22  fits over and is slidable relative to the transmitter housing  24 . The cover  50  has a front wall  52 , which extends across the front side  26  of the recessed portion  30 , a pair of side walls  54  and a back wall  58 , which help to maintain the orientation of the cover  50  when sliding between the open and closed position, and an end wall  56 , which is in surface contact with the springs  44 .  
         [0023]     The front wall  52  of the cover  50  includes a lock catch  60  and a stop slot  62 , and may include a LED viewing window  64 . The lock catch  60  is a recess in the front wall  52  that is sized slightly longer and slightly wider than the lock rib  38 , and is located so that it aligns with the lock rib  38  when the cover  50  is in its closed position. The lock rib  38  extends outward sufficiently from the front side  26  of the recessed portion  30  that it will extend into the lock catch  60  when the two are aligned. Accordingly, with the lock rib  38  engaged in the lock catch  60 , the cover  50  can be held closed against the bias of the springs  44 .  
         [0024]     The stop slot  62  is a recess in the front wall  52  that has a width about the diameter of the stop pin  40  and a length that is at least as long as the diameter of the stop pin  40  plus the distance traveled by the cover  50  between its closed and open positions. The stop slot  62  includes a stop end  66  that is located to engage with the stop pin  40  when the cover  50  is in its open position. Thus, the engagement of the stop pin  40  with the stop end  66  of the stop slot  62  acts as a travel limiter  67 , preventing the cover  50  from being pushed all of the way off the end of the housing  24  by the springs  44 . As an alternative, the stop pin may be located on and extending from the cover while the stop slot is located on the housing.  
         [0025]     The LED viewing window  64  is located to align with the LED when the cover  50  is in the closed position and may be just a hole through the front wall  52  or may also include a transparent material covering the hole. Thus, even though the buttons  32 ,  34 ,  36  are covered when the cover  50  is in its closed position, the user of the key fob  22  can still see when the LED is lit.  
         [0026]     While the lock catch  60  and stop slot  62  are illustrated as slots recessed in the cover front wall  52 , either or both may instead be formed from flanges extending outwardly from the cover front wall  52  that partially or fully surround the lock rib  38  and stop pin  40 , respectively. Also, while the cover  50  is shown completely wrapping around the front and back sides  26 ,  28  of the housing  24 , it may also wrap only partially around the back  28 , if so desired. And, while the cover  50  is shown sliding over the recessed portion  30  of the housing  24  in order to provide a smooth surface when closed, the housing  24  may be the same size along its length (i.e., no recess) with the cover  50  being larger and sticking out somewhat from the housing  24 .  
         [0027]     The operation of the key fob  22  will now be described. In operation, when the user desires to access the user operable buttons  32 ,  34 ,  36 , the user merely squeezes on the front and back sides  26 ,  28  of the transmitter housing  24  in proximity to the edge of the cover  50  near the center of each side  26 ,  28 . That is, the transmitter housing  24  is squeezed at about the first and second user release locations  46 ,  48 . There is a gap (not shown) between the front side  26  and back side  28  so, when squeezed, the front side  26  will flex. This flexing will cause the lock rib  38  to release from the lock catch  60 , thus allowing the compression springs  44  to automatically slide the cover  50  from its closed to its open position. The stop pin  40  will hit the stop end  66  of the stop slot  62 , thus preventing the springs  44  from shooting the cover  50  all of the way off the end of the housing  24 . With the cover  50  in its open position, the user has full access to all of the user operable buttons  32 ,  34 ,  36 .  
         [0028]     After the user is done using the buttons  32 ,  34 ,  36 , he merely slides the cover  50  against the bias of the springs  44  back into its closed position where the lock catch  60  will automatically engage the lock rib  38  and hold the cover  50  in its closed position against the bias of the springs  44 . Preferably, the lock rib  38  is sized and located relative to the lock catch  60  so that it will snap into the lock catch  60  sufficient to cause audible and tactile feedback for the user to confirm that the cover  50  is locked in its closed position. With the cover  50  now in its closed position, the buttons  32 ,  34 ,  36  cannot be inadvertently actuated by the user.  
         [0029]      FIG. 6  illustrates a second embodiment of the present invention. Since this embodiment is similar to the first, elements in this embodiment that are the same as elements in the first embodiment will be identified with the same element numbers, while elements that have changed and new elements will be identified with unique element numbers. The key fob  122  may include additional user operable buttons  70 ,  72  that are exposed at all times on front side  126  of the transmitter housing  124 , while only buttons  32 ,  34 ,  36  having certain features that are particularly undesirable to inadvertently actuate or buttons having features that are seldom used would be hidden by the cover  50 . In this way, the most used buttons  70 ,  72  are readily available to the operator, while the other buttons  32 ,  34 ,  36  can quickly and easily become accessible by releasing the automatically opening cover  20 . This embodiment also illustrates that the key fob  122  may include other common features associated with conventional key fobs without interfering with the automatically opening cover  50 . For example, the key fob  122  may have an attachment flange  74  to which a key ring  76  is mounted. These additional features are also applicable to the key fob of the first embodiment. In other respects, including the opening and closing of the cover  50 , the key fob  122  of this embodiment can be the same as the key fob  22  of the first embodiment, and so will not be described in any more detail.  
         [0030]     While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.