Abstract:
A flashlight battery charger has upper and lower receptacles for holding respective ends of a battery assembly therein securing against lateral forces. The battery charger structure is configured to be combined with a flashlight charger assembly and to form a common back plate therewith for securing mounting the combined assembly.

Description:
BACKGROUND 
     Rechargeable flashlight systems are essential accessories for emergency personnel and others needing a portable and readily-available source of illumination. One such flashlight system is that described in U.S. Pat. No. RE 37,092, the entire disclosure of which is incorporated by reference herein. Such flashlights are manufactured by Streamlight Inc. of Norristown, Pa., and sold under the “STINGER” brand family of rechargeable flashlight systems. Briefly, the &#39;092 patent describes a flashlight, battery assembly, and charging system in which the battery assembly is charged when the flashlight is stored in the charger unit. The charging unit securely holds the flashlight during charging, so that the charger unit may be mounted in a vehicle. 
     Due to the essential utility and effectiveness of these flashlights, the battery assembly therein may become discharged upon extended or repeated use, if sufficient recharging time is not provided. It would therefore be desirable to provide, as a further accessory to such a flashlight system, an auxiliary battery charger in which an auxiliary battery may be simultaneously charged and maintained in a charged condition, so that an exhausted battery may be rapidly replaced in the field. It would further be desirable to provide such an auxiliary battery charger as an integrated unit with the main flashlight charging unit. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, there is provided an auxiliary battery charger for a rechargeable flashlight system in which an auxiliary battery assembly is simultaneously charged and maintained in a charged condition for replacement of an exhausted battery assembly of a rechargeable flashlight. The auxiliary battery charger is configured to have an upper and lower receptacle for securely holding respective ends of a cylindrical battery assembly, in order to maintain the battery within the auxiliary charger during shocks and strong vibrations such as may be encountered in vehicular use. 
     According to another aspect of the present invention, an auxiliary battery charger is integrated with a charging unit of a rechargeable flashlight system, in order to charge and maintain an auxiliary battery assembly in a charged condition, while providing storage of the auxiliary battery assembly at the same location, and as a single unit with, the flashlight charging unit. 
     Other inventive aspects and advantages of the present invention shall be made apparent in the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES 
     The foregoing summary, and the following detailed description will be best understood in connection with the attached drawings, in which: 
     FIG. 1 is a front elevational view of a rechargeable flashlight system of the present invention; 
     FIG. 2 is a perspective view of the main and auxiliary charging units of the system of FIG. 1; 
     FIG. 3 is another perspective view of the main and auxiliary charging units of the system of FIG. 1; and 
     FIG. 4 is an exploded view of the system of FIG.  1 . 
    
    
     DETAILED DESCRIPTION 
     Referring now to FIG. 1, there is shown an elevational view of an integrated flashlight charging unit  40  and auxiliary battery charger  41 , and in which a rechargeable flashlight  20  and an auxiliary battery assembly  100  are shown installed in respective charging positions. The charging unit  40  includes a pair of jaws  46 , which snugly grip the head  28  of the flashlight  20 . The gripping action of the jaws  46  is adapted to securely hold the flashlight  20  and to allow the charging unit  40  be mounted in any desired orientation without the flashlight separating from the charging unit. The gripping action of the jaws  46  further allows the charging unit  40  to be mounted upon surfaces subject to vibration such as occurs within an automobile or other vehicle. 
     The auxiliary battery charger  41  includes an upper contact portion  43 , a longitudinal rib portion  45 , and a lower stop portion  47 . The longitudinal rib portion  45  extends along the longitudinal axis of the auxiliary battery charger  41  in parallel with the longitudinal axis of the battery assembly  100 , and joins with the upper contact portion  43  and the lower stop portion  47  at respective ends thereof. 
     In FIG. 2, the flashlight charging unit  40  and the auxiliary battery charger  41  are shown with the flashlight  20  and the auxiliary battery  100  removed. Within the upper contact portion  43  of the auxiliary battery charger  41 , there is provided a compressive member, such as a spring  51 . The spring  51  exerts a compressive force against the upper end of the battery in the charging configuration, thus urging the lower end of the battery against the lower stop portion  47 . In a preferred embodiment, the auxiliary battery assembly is of the type described in U.S. Pat. No. RE 37,092, which has both positive and negative contacts located at one end (herein designated the “upper” end for purpose of reference). The spring  51  also provides one of the electrical charging contacts to the battery. The other electrical charging contact to the battery is provided by spring  53 , which is also housed in the upper contact portion  43  in a concentric relationship with spring  51 . 
     In alternative embodiments, the functions of providing charging contacts and longitudinal compressive engagement of the battery within the auxiliary battery charger may be provided by separate structures located at either or both of the upper and lower ends portions of the auxiliary charger. For example, substantially stationary contacts may be provided at one end portion of the auxiliary battery charger, while a spring located at the lower stop portion may provide a compressive force to urge a contact end of the battery into engagement with such stationary contacts. Alternatively, an auxiliary battery charger for batteries of the type having positive and negative contacts at respective opposite ends thereof, may be provided with a spring contact at one end and a stationary contact at the other end. In yet another alternative embodiment, respective positive and negative charging contacts may be positioned upon a single spring-loaded member positioned in one end portion of the charger  41 . The preferred configuration shown in FIG. 2 is particularly advantageous in that longitudinal vibration of the charging unit  41  will not tend to disengage either of the battery contacts from the spring charging contacts. Because battery charging circuitry typically follows a predetermined sequence of charging current, the relative immunity from disengagement provided in the preferred configuration avoids potential resetting of the charging circuitry upon inadvertent contact disengagement from vibration, as may occur in less preferred configurations. 
     In order to prevent the upper end of the battery from lateral dislodgement from the charging configuration, such as due to vehicular vibration, the upper contact portion  43  has a rim portion  61  formed at a lower end thereof. In the preferred embodiment, the rim portion  61  encircles the lower end of the upper contact portion  43  from one side of the upper end of the rib portion  45  to the other, so that the upper contact portion forms a receptacle for receiving the upper end of the battery therein. Thus, the battery is held in place by compression and displacement of the compression member in the receptacle. Vents  50  are found in the receptacle, in order to vent gas from the battery during charging. In alternative embodiments, one or more rim segments may be provided in order to extend along an upper longitudinal portion of the battery, to resist dislodgement of the battery as would otherwise occur due to lateral vibrational force. The continuous rim portion  61 , as joined to the rib portion  45 , of the preferred embodiment shown provides a continuous side wall about the entire upper end of the battery, to resist forces along any lateral axis. 
     The lower stop portion  47  is more clearly seen in FIG.  3 . The lower stop portion provides a counteracting mechanical stop to the compressive force applied by the spring or springs in the upper contact portion  43 , to hold the battery stationary within the charger  41  along its longitudinal axis in the charging configuration. In the preferred embodiment, the lower stop portion  47  comprises a wall  71  projecting orthogonally from the lower end of the longitudinal rib portion. Along the wall  71  there are formed upward projections or ribs  73  which separate the lower end of the battery from the wall  71 , and provide gaps therebetween for venting of gas from the lower end of the battery assembly. The lower stop portion  47  preferably comprises a rim portion  74  about the upper end thereof thus forming a receptacle for receiving the lower end of the battery into the lower stop portion. The rim portion  74  counteracts lateral forces, such as vibrational forces, which would otherwise tend to surge the lower end of the battery assembly out of engagement with the lower stop portion  47 . In the preferred embodiment, the rim portion  74  is formed to continuously encircle the lower end of the battery from one side of the longitudinal rib portion  45  to the other side thereof. In alternative embodiments, such a means to counteract lateral force may be segmented or discontinuous. 
     It will be appreciated that formation of respective upper and lower receptacle portions at opposing ends of the longitudinal rib  45  results in a longitudinal open space along the longitudinal rib portion which is shorter than the overall length of the battery assembly. In order to insert the battery into the auxiliary charger  41 , the battery is first held at an acute angle to the longitudinal rib portion  45 , such that the upper end of the battery may be inserted into the upper receptacle to compress the springs  51 ,  53  therein. Then, when the springs are sufficiently compressed such that the lower end of the battery may clear the lower rim portion  74 , the battery is pivoted to a parallel orientation relative to the longitudinal rib portion  45  locking the battery in place. The battery may then be released, so that the springs will drive the lower end of the battery into abutment with the lower stop portion  47 . The longitudinal rib portion  41  preferably has a groove  62  formed along at least a portion thereof to accommodate alignment of the battery with the upper receptacle upon insertion of the upper end of the battery therein. 
     After charging, the battery may be removed from the auxiliary charger  41  by following the reverse order of insertion. First, the battery is moved upward against the springs  51 ,  53  in a direction parallel with the longitudinal rib  45 . When the battery has been moved sufficiently upward for the lower end of the battery to clear the lower rim portion  74 , the lower end of the battery is pivoted out of alignment with the lower stop portion  47 . Finally, by relaxing the upward pressure upon the battery  51 ,  53 , the springs in the upper contact portion  43  will drive the upper end of the battery out of the upper contact portion  43 , and the battery may be pulled away from the auxiliary charger  41  for placement into the flashlight. 
     Further construction details of the rechargeable flashlight system and auxiliary battery charger  41  are made apparent in the exploded view of FIG.  4 . The body of the auxiliary charger  41  is integrally formed with a laterally extending back plate portion  80 , which mates to the rear of the housing of charging unit  40  to provide the rear wall thereof. The springs  53  and  51  are mounted to a circuit board  83 , upon which may be mounted other electrical components such as a charge indicator LED  85  which extends through the forward wall of the upper contact portion  43  in the assembled condition. The circuit board  83  is held in the upper contact portion by respective slots (not shown) formed in interior surfaces thereof for holding the edges of the circuit board in a fixed position therein. A back plate  86  is positioned to form the rear wall of the upper contact portion, and the back plate  86 , the back plate portion  80  of the auxiliary charger body, and the charging unit  40  are held together by screws  90 . 
     Because the battery  100  has respective positive and negative contacts exposed in close proximity at the upper end  102  thereof, it is desirable to provide an insulating cap  91  to cover the upper end  102  of the battery  100  when it is transported or stored separately from the charging system. Inadvertent conduction between the battery contacts would otherwise pose a risk of fire or explosion. In order to store the insulating cap  91  when the battery  100  is positioned in the auxiliary charger, a cap holding structure, such as a circular arrangement of raised fins  95 , is provided on the auxiliary charger upon which the cap  91  is placed for storage. 
     The terms and expressions which have been employed are used as terms of description and not of limitation and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described, or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.