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BACKGROUND OF THE INVENTION  
         [0001]    This invention relates generally to window locks and, more particularly to a locking apparatus for slidable windows such as horizontally slidable rear truck windows.  
           [0002]    Keys are occasionally inadvertently locked in a vehicle, requiring the vehicle operator to retrieve another set of keys or obtain the services of a locksmith. On other occasions, however, an operator may desire to intentionally lock his keys in the vehicle so as not to have to carry them, e.g. while swimming at a beach or pool.  
           [0003]    Therefore, it would be desirable to have a lockable sliding window apparatus that would enable an operator to open the window upon entering a correct code. Further, it is desirable to have a lockable sliding window apparatus which does not require a user to carry any operating hardware.  
         SUMMARY OF THE INVENTION  
         [0004]    A lockable sliding window apparatus according to the present invention includes a window frame with a pair of window units mounted therein, at least one of the window units being slidable. Each window unit includes a vertical frame member having a configuration for mating engagement when the window units are in a closed configuration. A locking assembly is coupled to the vertical frame members and includes primary and secondary portions. The primary portion includes a combination dial lock mounted to an outer segment of one vertical frame member and includes dials which may be manipulated by a user to enter an appropriate unlock code. The combination dial lock includes a window pin which extends through the outer segment but is immovable when the combination dial lock is locked. The secondary portion of the locking assembly is mounted to an inner segment of the one vertical frame member and includes a window pin extending through corresponding through-holes of the vertical frame members of both window units. Therefore, the window pin holds/locks the pair of window units in the closed configuration. The window units may be selectively released when the combination dial lock is unlocked so that a user may depress the lock pin to urge the window pin out of its blocking position in the through-holes. Alternatively, the locking assembly may include a radio frequency identification (RFID) module capable of electromagnetically recognizing a properly coded tag and, correspondingly, actuating a solenoid to unlock the window units.  
           [0005]    Therefore, a general object of this invention is to provide a lockable sliding window apparatus for selectively locking horizontally slidable windows against unauthorized entry.  
           [0006]    Another object of this invention is to provide a lockable sliding window apparatus, as aforesaid, having a combination dial lock for enabling slidable window units to be opened from the outside upon entry of an appropriate combination code.  
           [0007]    Still another object of this invention is to provide a lockable sliding window apparatus, as aforesaid, having a release tab mounted to the interior of the window units for enabling the window units to be slidably opened from the inside without respect to the combination dial lock configuration.  
           [0008]    Yet another object of this invention is to provide a lockable sliding window apparatus, as aforesaid, which may be manufactured as an original equipment or after-market apparatus for use in vehicles.  
           [0009]    A further object of this invention is to provide a lockable sliding window apparatus, as aforesaid, which utilizes a radio frequency identification module as the window locking mechanism.  
           [0010]    Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a perspective view of a lockable sliding window apparatus according to one embodiment of the present invention with the window units in a closed configuration;  
         [0012]    [0012]FIG. 2A is a perspective view of the apparatus as in FIG. 1 with the window units in an open configuration;  
         [0013]    [0013]FIG. 2B is an isolated perspective view on an enlarged scale of the locking assembly shown in FIG. 2A;  
         [0014]    [0014]FIG. 3A is a perspective front view of the apparatus as in FIG. 1;  
         [0015]    [0015]FIG. 3B is a sectional view taken along line  3 B- 3 B of FIG. 3A;  
         [0016]    [0016]FIG. 4A is a side view of the locking assembly shown in FIG. 3B in a locked configuration;  
         [0017]    [0017]FIG. 4B is a side view of the locking assembly shown in FIG. 3B in an unlocked configuration;  
         [0018]    [0018]FIG. 4C is a side view of the locking assembly shown in FIG. 3B in an unlocked configuration and with the lock pin depressed;  
         [0019]    [0019]FIG. 5A is a front view of the apparatus as in FIG. 1;  
         [0020]    [0020]FIG. 5B is a sectional view taken along line  5 B- 5 B of FIG. 5A;  
         [0021]    [0021]FIG. 6A is a front perspective view of a lockable sliding window apparatus according to another embodiment of the present invention;  
         [0022]    [0022]FIG. 6B is an isolated view of an electronic keypad of the apparatus as in FIG. 6A on an enlarged scale;  
         [0023]    [0023]FIG. 7A is a rear perspective view of the apparatus as in FIG. 6A;  
         [0024]    [0024]FIG. 7B is an isolated view of a solenoid and flanges of the apparatus as in FIG. 7A on an enlarged scale;  
         [0025]    [0025]FIG. 8A is a fragmentary view of the apparatus as in FIG. 7B;  
         [0026]    [0026]FIG. 8B is a sectional view taken along line  8 B- 8 B of FIG. 8A;  
         [0027]    [0027]FIG. 8C is a perspective view of a transponder according to the invention shown in FIG. 6A;  
         [0028]    [0028]FIG. 9A is a flowchart illustrating the logic performed by a logic circuit according to the invention of FIG. 6A; and  
         [0029]    [0029]FIG. 9B is a flowchart illustrating additional logic performed by the logic circuit according to the invention shown in FIG. 6A.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0030]    A lockable sliding window apparatus according to the present invention will now be described in detail with reference to FIGS. 1 through 9B of the accompanying drawings.  
         [0031]    A lockable sliding window apparatus  10  according to one embodiment of the present invention is shown in FIGS. 1 through 5B and includes a window frame  12  having a generally rectangular configuration suitable to be mounted in an opening for the rear window of a pickup truck. However, this apparatus  10  may be utilized in other window applications and therefore may have any other suitable configuration. First  14  and second  16  window units are mounted within the window frame  12  (FIG. 2A). The first  14  and second  16  window units include respective secondary frames in which respective window panels  18 ,  20  are mounted, each window panel being a pane of glass or transparent plastic. Longitudinally extending segments of the window frame  12  include a guide rail  13  on which at least the first window unit  14  is mounted on the guide rail  13  for horizontal slidable movement therealong although both the first  14  and second  16  window units are preferably slidably mounted for movement therealong (FIG. 2A). Of course, the window frame  12  may include other stationary window panes  22 .  
         [0032]    Respective secondary window frames include first  24  and second  26  vertical frame members. The vertical frame members are configured to be superimposed over one another when the window units are moved to a closed configuration. More particularly, the second vertical frame member  26  includes an outer segment  28  and an inner segment  32  joined together to form a channel having a female configuration capable of receiving the first vertical frame member  24  therein (FIG. 3B). Therefore, the first vertical frame member  24  is essentially captured by the second vertical frame member  26  at the closed configuration. It should be observed that the inner segment  32  is only necessary relative to the locking assembly, as to be described more fully below. Inner  32  and outer  28  segments of the second vertical frame member  26  define through-holes  34 ,  30 , respectively (FIG. 4A). In addition, the first vertical frame member  24  defines a through-hole  25  (FIG. 2B). When the first  14  and second  16  window units are at the closed (mated) configuration, all of the through-holes are in alignment for use as to be described below.  
         [0033]    The lockable sliding window apparatus  10  includes a locking assembly  36  for preventing unauthorized opening of the windows from the outside. More particularly, the locking assembly  36  includes a primary lock housing  38  fixedly attached to the outer segment  28  of the second vertical frame member  26  and a secondary lock housing  40  fixedly attached to the inner segment  32  thereof (FIG. 3B).  
         [0034]    The primary lock housing  38  includes a dial-type combination lock mechanism having a dial pin  42  positioned in an interior space of the primary lock housing  38  and being urged downward by a coil spring  46  (FIG. 3B). A lock pin  48  extends through the primary lock housing  38  generally perpendicular to the dial pin  42 , the lock pin  48  defining a recess  50  therein. A lock ball  54  is positioned intermediate the dial pin  42  and lock pin  48  and is normally urged to engage the lock pin recess  50 . The combination lock mechanism includes a plurality of dials  56  mounted for rotation about the dial pin  42 , each dial defining a dial pocket  58  (FIG. 4B). It is understood that each dial  56  includes an indicium and may be manipulated by a user when setting the dials  56  to an appropriate “unlock” code. It is further understood that each dial pocket  58  corresponds to a predetermined code indicium.  
         [0035]    The lock mechanism further includes a plurality of dial balls  60  situated intermediate respective dials  56  and the dial pin  42  (FIGS.  4 A- 4 C). The dial balls  60  are captured within depressions  44  formed in the dial pin  42  such that the dial pin  42  is immovable (FIG. 4A). In other words, the combination lock mechanism is locked while the dial balls  60  are captured by the dial pin depressions  44 . However, when a dial  56  is rotated to its respective code position, its dial pocket  58  becomes aligned with a corresponding dial ball  60  (FIG. 4B). Thereafter, a depression of the lock pin  48  pushes the lock ball  50  upwardly in a camming action, urging the dial pin  42  upwardly and compressing the spring  46 . The dial balls  60  are shifted into respective dial pockets  58  by this action (FIG. 4C).  
         [0036]    The lock pin  48  extends through the primary lock housing  38  generally perpendicularly to the dial pin  42  and adjacent to the lock ball  54 . A spring  52  is coupled to an inner end of the lock pin  48  and biases it to extend outwardly through an outer surface of the primary lock housing  38  (FIG. 4A). The lock pin  448  extends through the outer segment through-hole  30 . In its normal configuration, the lock pin recess  50  is aligned with the lock ball  54 , the lock ball being urged to nest therein by the dial pin spring  46 . Therefore, the lock pin  48  is immovable so long as the dial balls  60  are captured in the dial pin depressions  44  (FIG. 4A). However, when the combination lock mechanism is in its unlocked state (FIG. 4C), a user may depress the end of the lock pin  48  that extends from the primary lock housing  38  so as to extend the lock pin  48  through the through-holes  30 ,  25  of both the outer segment  28  of the second vertical frame member  26  and first vertical frame member  24 , respectively. This action enables the first vertical frame member  24  to be released from the mating relationship with the second vertical frame member  26 , as yet to be described more fully below. It should be appreciated that the inner end of the lock pin  48  presents a rounded configuration such that the first vertical frame member  24  can gently push past it with minimal resistance.  
         [0037]    The secondary lock housing  40  is mounted to the inner segment  32  of the second vertical frame member  26  at a point covering the through-hole  34  defined thereby (FIG. 4A). A window pin  62  is positioned within the secondary lock housing  40  and urged inwardly toward the inner segment through-hole  34  by a compression spring  64 . The inner end of the window pin  62  includes a tapered or draft angle such that the pin is moved outwardly (compressing the spring  64 ) when the first window unit  14  is moved from an open configuration to a closed configuration. In other words, open window units may be freely closed, the window pin  62  automatically springing through the inner segment and first vertical frame member through-holes when the window units arrive at the closed configuration. As all of the through-holes are in alignment, the window pin  62  and lock pin  48  have a common imaginary vertical axis. Once in this configuration, the window units may not be opened from the outside until the lock pin  48  is depressed to push the window pin  62  out of the first vertical frame member through-hole  25  (FIG. 4C).  
         [0038]    The window pin  62  includes an outer end extending through an outer surface of the secondary lock housing  40  (FIG. 3B). A pull tab  66  is pivotally coupled to the outer end although a fixed attachment would also be suitable. The pull tab  66  enables a user to manually pull the window pin  62  out of the first vertical frame member through-hole  25 , i.e. out of its locking configuration. This enables a user to essentially unlock the window units from the inside and freely slidably move the window units. The window pin spring  64  is compressed when the pull tab  66  is pulled and again urges the window pin  62  in the direction of the inner segment  32  when released.  
         [0039]    In use as a rear window of a truck, a user may freely open and close the first  14  and second  16  window units from inside the vehicle. It is understood, of course, that once the window units are in the closed configuration, the pull tab  66  must be used to partially withdraw the window pin  62  to allow the first vertical frame member  24  to be released from the second vertical frame member  26 . Thus, the window units  14 ,  16  are automatically locked when at the closed configuration. To unlock the window units from the outside, a user may rotate the dials  56  to a predetermined combination code. When properly rotated, the lock ball  54  and dial pin  42  are free to be shifted upwardly upon a user depression of the lock pin  48 . A depression of the lock pin  48  causes the lock pin  48  to bear against the window pin  62  and push the window pin  62  out of the first vertical frame member through-hole  25 . This releases the first vertical frame member  24  and allows the first window unit  14  to be opened. In this way, an authorized user may gain access to a vehicle without having to carry keys or other operational hardware.  
         [0040]    A lockable sliding window apparatus  70  according to another embodiment of the present invention is shown in FIGS. 6 through 9B. This apparatus  70  includes a window frame  72  and first  74  and second  76  window units having a construction substantially similar to that of the embodiment first described above (FIG. 7A). The first  74  and second  76  window units include respective first  82  and second  84  vertically disposed frame members having corresponding configurations that bear against one another when the windows are slidably moved to a closed configuration. In fact, the vertical frame members may include a configuration and hardware to provide a seal therebetween at the closed configuration.  
         [0041]    The apparatus  70  according to this embodiment also includes a locking assembly. The locking assembly includes an electronic numeric keypad  86  mounted to a front surface of the first vertical frame member  82  for receiving a security code input by a user (FIG. 7B). Further, the locking assembly includes a solenoid module  88  mounted to a rear surface of the first vertical frame member  82 , the solenoid module providing a housing in which a lock pin  90  is mounted for reciprocative movement between retracted and extended configurations (FIG. 8B). A battery  92  is also mounted within the solenoid module  88  that is electrically connected to the keypad  86  and lock pin  90 .  
         [0042]    A main flange  94  defining a through-hole is mounted to a rear surface of the second vertical frame member  84  and is positioned such that the through-hole is in vertical alignment with the lock pin  90  when the window units are at the closed configuration. More particularly, the main flange  94  is positioned adjacent an open bottom of the solenoid module housing when the window units are closed (FIGS. 8A and 8B). For added stability, auxiliary flanges  96 ,  98  may be positioned above and below the main flange  94  (FIG. 7B). The solenoid module is capable of moving the lock pin  90  between an extended configuration extending through the main flange through-hole and a retracted configuration not extending through the flange.  
         [0043]    Comparator circuitry (not shown) is positioned within the solenoid module  88  and electrically connected to the battery  92 , the comparator circuitry allowing current from the battery to energize the lock pin  90  to move from the extended/locked configuration to the retracted configuration when the input security code matches a predetermined security code. Therefore, when the window units  74 ,  76  are in the closed configuration and the predetermined security code is input, the lock pin  90  retracts through the flange through-hole so as to unlock the window units.  
         [0044]    Further, a lock button  100  is coupled to a top of the solenoid module  88  and may be manually depressed or retracted. The lock button  100  is electrically connected to the battery  92  such that button depression enables current to flow from the battery  92  to the lock pin  90  so as to energize the lock pin  90  to move from the retracted configuration to the extended configuration. Similarly, retraction of the lock button  100  energizes the lock pin  90  to return to the retracted configuration. Therefore, the lock button  100  allows the window units  74 ,  76  to be locked or unlocked by a user from the inside of the window frame  72 .  
         [0045]    Further, the solenoid module  88  may include a logic circuit  102  positioned within the solenoid housing and electrically connected to the battery  92 . It is understood that the logic circuit  102  may include the comparator circuitry described previously although the comparator circuitry may be included separately and electrically connected to the logic circuit  102 .  
         [0046]    A pair of sensors may be mounted to a bottom of the upper auxiliary flange  96  although it is understood that they may be mounted to a bottom of the solenoid module housing if the auxiliary flanges  96 ,  98  are not included (FIG. 8B). Each sensor is a touch sensor for detecting contact with the main flange  94  although a proximity sensor would also work. More particularly, a first sensor  104  is positioned on the bottom of the upper auxiliary flange  96  to the distal/far side of an upper auxiliary flange aperture relative to the second vertical frame member  84 . In other words, the first sensor  104  is not contacted by the main flange  94  until the main flange  94  is substantially aligned to receive the lock pin  90  (FIG. 8B). When contact is sensed, the first sensor  104  generates a first output signal and conveys it to the logic circuit  102 . Thereafter, the logic circuit  102  may energize the lock pin  90  to move to the extended configuration. Thus, the windows are automatically locked when closed.  
         [0047]    A second sensor  106  is positioned on the bottom of the upper auxiliary flange  96  to the proximal/near side of the upper auxiliary flange aperture. In other words, the second sensor  106  may be contacted as the main flange  94  is moving toward alignment with the lock pin  90  but the vertical frame members are not yet in a closed configuration. When contact is sensed, the second sensor  106  generates a second output signal and conveys it to the logic circuit  102  which, in turn, energizes the lock pin  90  to move to the retracted configuration. Therefore, the second sensor  106  ensures that the lock pin  90  is out of the way to allow closure of the window units. The logic of the operation of the proximal/second  98  and distal/first  96  touch sensors is illustrated in FIG. 9B.  
         [0048]    Further, the solenoid module  88  may include radio frequency identification (RFID) components. More particularly, a transceiver  110  and an antenna  112  are positioned within the solenoid module housing and are electrically connected to the logic circuit  102  and battery  92  (FIG. 8B). Preferably, the transceiver  110  is packaged with its own decoder circuitry although the decoder may be included in the logic circuit  102 . Together, the transceiver  110  with decoder and antenna  112  may be referred to as an interrogator. The RFID components also include a transponder  114  separate from the solenoid module  88  (FIG. 8C) that may be conveniently carried by a user. The transponder  114  may take the form of a smart card, sticker, token, etc.  
         [0049]    In function, the transceiver  110  transmits an electromagnetic field at a predetermined radio frequency. The range of this field depends upon the power output and radio frequency used. When the transponder  114  is within range, it receives the transmitted waves and returns an identification signal. Preferably, the transponder  114  is a passive tag which obtains sufficient operating power from the transmitted wave itself and needs no additional power source. However, an active-type transponder would also work but would require its own power source, such as a battery. The return signal is received by the antenna  112  and decoded so as to determine if the transponder  114  corresponds to an authorized user. If so, then the logic circuit  102  is adapted to energize the solenoid module  88  to unlock the window units, as previously described.  
         [0050]    The solenoid module  88  includes a mode switch  116  electrically connected to the logic circuit  102  for toggling between two modes/levels of security. In one mode, the logic circuit  102  energizes the solenoid module  88  to unlock the lock pin  90  solely upon entry of the predetermined security code, as indicated by reference numerals  120 ,  122 , respectively, in FIG. 9A. In another mode, entry of the correct security code  124  is first required. Then, the transceiver  110  sends out a radio frequency (RF) signal and receives a return signal from the transponder  114  as indicated at  126  and  128 , respectively. If the return signal is recognized as being authorized  130 , then the solenoid module  88  is energized to unlock  120 .  
         [0051]    It is understood that while certain forms of this invention have been illustrated and described, it is not limited thereto except insofar as such limitations are included in the following claims and allowable functional equivalents thereof.

Summary:
A lockable sliding window apparatus includes sliding window units having respective vertical frame members that are coupled at a closed configuration. Inner and outer segments of one frame member receive the other frame member therebetween. A combination dial lock is mounted to the outer segment and includes a lock pin extending through therethrough. The lock pin is immovable when the combination lock is locked and vice versa. A window pin extends through the outer segment of the one frame member and through the other frame member for locking the other frame member in place. When the combination lock is unlocked, the lock pin may be user actuated to release the window pin for opening the window units. Another embodiment includes an electronic keypad by which a user may enter a security code. Proper entry actuates a solenoid to retract a lack pin that may otherwise lock the window units together.