Patent Publication Number: US-9905068-B2

Title: Key fob with foam lock status indicator

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a lock status indicator for a key fob used for remotely locking and unlocking a vehicle door that informs the user for a limited period of time after having left the vicinity of the vehicle whether the door lock button had been depressed to actuate the door lock. 
     The use of key fobs for remotely locking and unlocking vehicle doors has become almost universal. In its simplest form the key fob is a hand held device having a depressable button labeled “lock” or some similar label, and another depressable button labeled “unlock” or some similar label. Located within the key fob are the electronics and power source required to transmit a signal via a modulated radio frequency or via infrared to a receiver communicating with the lock/unlock mechanism of a door or doors of a vehicle upon depression of the “lock” or “unlock” button. Additional buttons, such as a “panic” button for activating the vehicle&#39;s horn as an alarm, may also be present. 
     After parking a vehicle and walking away to perform an errand, or for other reasons, a user may not remember whether the vehicle&#39;s door was locked at the time of departure by having depressed the “lock” button of the key fob. Rather than having to walk back towards the vehicle into a proximity where the lock button can be depressed to insure activation of the door lock, it would be desirable to have some indicator means associated with the fob itself to inform the user as to whether the lock button had indeed been depressed upon departing the vehicle. 
     There have been several suggestions in the prior art for ways for a key fob to indicate the status of a door lock. Most are complex and expensive, involving electronic communication between a sensor in the door and a receiver in the fob. See, for example, U.S. Pat. No. 8,362,898. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a simple and inexpensive lock button status indicator member for use with a key fob having a depressable lock button for remotely activating a locking mechanism communicating with a door, such as a vehicle door. 
     The lock button status indicator member is formed of a viscoelastic polyurethane foam having a slow recovery time. 
     The lock button status indicator member has a base configured to abut the upper surface of the lock button, but is of a size that does not interfere with depression of the lock button into the key fob case. 
     An adherent, such as a pressure sensitive adhesive, is located on the lower surface of the base of the lock button status indicator member, and is adapted to adhere the lower surface of the base to the upper surface of the lock button. 
     The lock button status indicator member can inform the user for a limited period of time after having left a vehicle whether the lock button on the key fob had been depressed to actuate the door lock. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a prior art key fob; 
         FIG. 2  is a front view of the key fob of the present invention with a status indicator member attached to the upper surface of the “lock” button 
         FIG. 3  is a side view of the lock button and attached status indicator member of the key fob of the present invention; 
         FIG. 4  is an end view of the lock button and attached status indicator member of the key fob of the present invention; and 
         FIG. 5  is a side view of the lock button with attached status indicator member of the key fob of the present invention with the status indicator shown in a depressed mode. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     A generic prior art vehicle key fob  10  is illustrated in  FIG. 1 . 
     Key fob  10  has a case  20  which contains the electronics and power source (not shown) required to transmit a signal via a modulated radio frequency or via infrared to a receiver communicating with the lock/unlock mechanism of a door or doors of a vehicle upon depression of the “lock” or “unlock” button to lock or unlock a door or doors of a vehicle. Such elements are well known in the vehicle key fob art. 
     Key fob  10  has a “lock” function button  30  and an “unlock” function button  40 . Prior art key fobs typically have a “panic” button and other buttons, not shown. A vehicle ignition key  50  is attached to fob  10 , although with some vehicles, such as Mercedes Benz, a portion of the fob itself forms an electronic key for insertion into the ignition. 
     In  FIG. 1  the generally rectangular shape of fob  10 , and the arrangement and shape of the various buttons on fob  10 , is for discussion purposes only as prior art fobs come in many different shapes and the various buttons located thereon take other arrangements or forms. Additional buttons for other functions may also be located thereon, as known in the prior art. Some prior art fobs use symbols to identify the function of the various buttons rather than the words such as “lock”, “unlock”, etc. 
     The lock status indicator member  130  of the present invention, described in detail below, can be used as an after-market add-on to any existing prior art key fob which, as discussed above, can take many different shapes, button arrangements, and button identifiers. For purpose of describing the invention, the generic key fob  10  illustrated in  FIG. 1  is used as the key fob with which the lock status indicator member  130  of the present invention is employed. 
       FIG. 2  shows the key fob  10  of  FIG. 1  to which a lock button status indicator member  130  has been added. The lower surface of the base of status indicator member  130  is attached to the upper surface of lock button  30  by means of a pressure sensitive adhesive  132 , or other adherent or attachment means, as best seen in  FIGS. 3 and 4 . 
     Status indicator member  130  is shown as having a substantially semi-circular cross-section in  FIG. 4 ; however, other cross-sections may be employed. 
     Status indicator member  130  is shown as having a substantially rectangular base in  FIGS. 2-4 , which mirrors the substantially rectangular shape of lock button  30 . However, other base shapes may be employed, particularly those that mirror the shape of a particular commercially used lock button such as, for example, substantially circular. 
     Whatever shape is chosen for the base of the status indicator member  130 , its edge (if circular) or edges (if rectangular or other polygon) should not extend beyond the adjacent edge or edges of the upper surface of lock button  30 , and preferably is located inwardly therefrom as seen in  FIGS. 2-5 , so as not to interfere with the depression of lock button  30  into case  20  when it is actuated. 
     Since status indicator member  130  will substantially or entirely cover the word “lock” or other indicia on the upper surface of lock button  30 , the word “lock”, the letter “L”, or other indicia can be printed on the upper surface of status indicator member  130  to indicate that the lock button  30  resides below. 
     Status indicator member  130  is formed of a viscoelastic polyurethane foam, commonly called “memory foam”. Memory foam has an open-cell solid structure that forms an indentation when subjected to a force acting against its surface and slowly returns to its original shape once the force is released. The time required to return to its original shape is referred to as its “recovery time”. Commercially available memory foam can have recovery times that range from very slow to extremely fast. 
     For purposes of the present invention, a memory foam is selected having a slow recovery time rather than a fast recovery time in order to maximize the time available for it to act as a status indicator, as discussed below. The selection of a memory foam having a slow recovery time from among those commercially available is well within the scope of one skilled in the memory foam art. The thickness or height of status indicator member  130  should be such as to, in conjunction with the properties of the memory foam selected, provide a reasonable recovery time for the status indicator purposes described herein. 
     Status indicator member  130  formed of memory foam is attached to lock button  30  of a key fob, as discussed above. Upon exiting a vehicle, the user depresses the lock button  30  by depressing status indicator member  130  attached to the upper surface thereof with a finger or thumb. As seen in  FIG. 5 , the downward force  140  of the user&#39;s finger or thumb acting upon the upper surface of status indicator member  130  forms an indentation  134  which only slowly returns to its original shape because the memory foam from which it has been made has been selected to have a slow recovery time. Recovery times of about 2-3 minutes are readily achievable. Involving a finger or thumb nail in depressing status indicator member  130  would form a crease  136  in the bottom of the finger or thumb indentation  134 , providing a somewhat lengthier recovery time of up to about 5 minutes. 
     Instructions provided with status indicator member  130  could specify a recovery time beyond which status indicator member  130  would no longer provide the user with information as to whether the lock button  30  had been depressed after departure from the vehicle. Alternatively, the user could determine the recovery time for his/her specific fob and finger pressure by depressing status indicator member  130  and measuring the time it takes for the indentation  134  or  136  to fully disappear. 
     The user, after having walked away from his/her vehicle, but while still within the recovery time of status indicator member  130 , can glance at key fob  10  and see if status indicator member  130  remains somewhat indented, i.e., has not fully recovered its original shape, thereby confirming activation of lock button  30 . Lack of any remaining portion of indentation  134  or  136  within the recovery time of status indicator member  130  indicates that lock button  30  was not depressed and that the vehicle&#39;s door(s) remain unlocked. 
     While the invention has been described relative to a key fob  10  for remotely locking and unlocking a vehicle door having a lock button status indicator member  130  attached to the lock button  30 , it is clear that the lock button status indicator member  130  of the present invention can be used with a key fob having a lock button for locking doors other than vehicle doors, such as entry and exit doors to buildings, garage doors, internally located security doors, etc. 
     It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments of this invention without departing from the underlying principles thereof. The scope of the present invention should, therefore, be determined only by the following claims.