Abstract:
Battery corrosive electrolyte leak is reduced by using spacers (which can be made of a shock absorbing material) between each pair of three or more batteries held in a series configuration so that a resilient contact provides an electrical contact between the pair of batteries and the thickness of the spacer prevents a second end of a first battery from contacting the first end of the second battery.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part application of Ser. No. 15/171,392, filed Jun. 2, 2016, which is a continuation application of Ser. No. 14/869,628 and also Ser. No. 14/869,962, both of which were filed Sep. 29, 2015, now issued as U.S. Pat. Nos. 9,368,767 and 9,368,768, the disclosures of all of which are specifically incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is in the field of reducing minimizing battery corrosive electrolyte leakage from devices that use batteries, including alkaline and rechargeable batteries, and is especially concerned with minimizing battery corrosive electrolyte leakage in portable, hand-held devices, one example of which is a flashlight, which use batteries held in a battery compartment in an in series arrangement. 
       BACKGROUND OF THE INVENTION 
       [0003]    Batteries of all sizes and types, including chargeable and non-rechargeable, are used in a variety of devices to provide power to electrical circuits. 
         [0004]    Alkaline batteries have provided power to consumer and hand-held devices, one example of which is a flashlight, for decades. A general description of the construction of alkaline batteries is described in the prior art, an example of which is the article found at http://www.electrical4u.com/alkaline-batteries, as well as a technical bulletin about Duracell® batteries found at http://ww2.duracell.com/en-US/Global-Technical-Content-Library/Technical-Bulletins.jspx, both of which are incorporated by reference herein, from which  FIG. 1  and the following description of such construction is obtained. The body of a battery, generally designated as  100 , is made of a hollow steel can  102  comprised of an outer cylindrical wall  1020 C, a top surface  102 TC and a bottom surface  102 BC. Can  102  contains all materials of the battery. A positive cap with a nipple  103  of battery  100  is projected from the top of can  102 . A manganese dioxide cathode powder mix  104  is pressed against the inner steel wall of can  102  so that the steel case of the can becomes the cathode current collector and serves as the positive terminal of the cell. The inner surface of the thick layer of cathode mixture is covered with a porous separator  105  which isolates the electrodes of the battery. The central space, inside separator  105 , is filled by a zinc anode powder  106 . The porous nature of the anode, cathode, and separator materials allows them to be thoroughly saturated with the alkaline electrolyte solution. A metallic pin  107  is welded to the external anode cap  111  and extends through a plastic cap or grommet  109  into the center of the anode powder mix maintaining intimate contact. This pin is called a negative collector pin or an anode current collector. Plastic cap or grommet  109  is sealed to the steel can  102  by means of radial crimping pressure and a sealant. Anode cap  111  is electrically isolated from the positive cell case  102  with an insulator  110 . A vent mechanism  112  is incorporated into the plastic grommet  109  to protect against cell rupture. An outer insulative wrapping  102 W is also commonly applied to can  102  which is also used to contain printed material, such as trademarks and trade dress of the battery manufacturer. 
         [0005]    Batteries, including alkaline batteries, are often aligned in series, in which a positive terminal of one battery is in direct contact with a negative terminal of another battery. Using a flashlight as an example, it is well known in the prior art to include a battery compartment, such as a barrel, in which batteries (such as AAA, AA, C or D cell size) are aligned in series. While such an arrangement is the common and traditional arrangement, there have been prior suggestions that steps be taken to protect battery electrodes in a series arrangement where two batteries connect with each other, such as through the use of a battery spacer and resilient conductor as taught in U.S. Pat. Nos. 5,645,955 and 5,795,675. 
         [0006]    However, despite the fact that batteries, including alkaline batteries, have been used in a variety of devices for decades, there has been a well-known problem that batteries can leak battery corrosive electrolyte over time, causing problems related to cleaning such leaks and sometimes ruining a device in which the leak occurs. 
         [0007]    Accordingly, the present invention addresses a long-felt need for a way to minimize battery corrosive electrolyte leaks in devices that use batteries, including but not limited to, flashlights. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is generally directed to reducing battery corrosive electrolyte leak by using spacers (which can be made of a shock absorbing material) between each pair of batteries held in a series configuration of three or more batteries so that a resilient contact provides an electrical contact between the pair of batteries and the thickness of the spacer prevents a second end of a first battery from contacting the first end of the second battery. 
         [0009]    Accordingly, it is a primary object of the present invention to reduce battery corrosive electrolyte leakage in devices in which three or more batteries are held in a series configuration. 
         [0010]    This and further objects and advantages will be apparent to those skilled in the art in connection with the drawings and the detailed description of the invention set forth below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  illustrates a cutaway view of a Duracell® cylindrical alkaline battery which constitutes prior art. 
           [0012]      FIG. 2  is a top view illustrating a first design of a shock absorbing spacer assembly in accordance with the present invention,  FIG. 3  is a cross sectional view of  FIG. 2 ,  FIG. 5  is a side view of  FIG. 2  and  FIG. 4  illustrates a resilient contact used in the assembly of  FIG. 2 . 
           [0013]      FIG. 6  is a top view illustrating a second design of a shock absorbing spacer assembly in accordance with the present invention,  FIG. 7  is a cross sectional view of  FIG. 6 ,  FIG. 9  is a side view of  FIG. 6  and  FIG. 8  illustrates a resilient contact used in the assembly of  FIG. 6 . 
           [0014]      FIG. 10  is a top view illustrating a third design of a shock absorbing spacer assembly in accordance with the present invention,  FIG. 11  is a cross sectional view of  FIG. 10 ,  FIG. 13  is a side view of  FIG. 10  and  FIG. 12  illustrates a resilient contact used in the assembly of  FIG. 10 . 
           [0015]      FIG. 14  is a top view illustrating a fourth design of a shock absorbing spacer assembly in accordance with the present invention,  FIG. 15  is a cross sectional view of  FIG. 14 ,  FIG. 17  is a side view of  FIG. 14  and  FIG. 16  illustrates a resilient contact used in the assembly of  FIG. 14 . 
           [0016]      FIGS. 18, 20 and 22  each illustrate a spring design that can be used in a shock absorbing spacer assembly in accordance with the present invention as illustrated in  FIGS. 19, 21 and 23 , respectively. 
           [0017]      FIG. 24  illustrates a flashlight the shock absorbing spacer of  FIG. 2  being used in a flashlight while  FIG. 25  is a close up view of a portion of  FIG. 24 . 
           [0018]      FIG. 26  illustrates an outer member of a tail cap that receives an inner member of a tail cap illustrated in  FIG. 29  in accordance with the present invention.  FIG. 27  is an end view of the outer member of  FIG. 26  while  FIG. 28  is a cross sectional view of  FIG. 27 .  FIG. 30  is an end view of the inner member of  FIG. 29  while  FIG. 31  is a cross sectional view of  FIG. 30  and  FIG. 32  is an end view looking at the back side of  FIG. 31 . 
           [0019]      FIG. 33  illustrates the inner member of  FIG. 29  screwed into the threads of a flashlight barrel with the male and female splines of inner and outer tail cap members of  FIGS. 26 and 29  engaged while  FIG. 34  shows the outer tail cap member of  FIG. 33  screwed into the inner tail cap member. 
           [0020]      FIG. 35  is an assembled two piece tail cap, illustrated in  FIGS. 26 and 29 , except that a shock absorbing material  202  has been added to the inner member while  FIG. 36  is an exploded view of the assembly of  FIG. 35  and  FIGS. 37 and 38  are identical to  FIGS. 33 and 34  except for the addition of shock absorbing material  202 . 
           [0021]      FIG. 39  illustrates a replacement tail cap with a terminal end shock absorber in accordance with the present invention while  FIG. 40  is an exploded view of  FIG. 39 . 
           [0022]      FIG. 41  illustrates a second replacement tail cap with a terminal end shock absorber in accordance with the present invention while  FIG. 42  is an exploded view of  FIG. 41 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    In the Figures and the following detailed description, numerals indicate various physical components, elements or assemblies, with like numerals referring to like features throughout both the drawings and the description. Although the Figures are described in greater detail below, the following is a glossary of elements identified in the Figures.
     1  flashlight     2  shock absorbing spacer     11  barrel of flashlight  1       11 T thread of barrel  11       12  head of flashlight  1       13  light source of flashlight  1       14  tail cap of flashlight  1       20  shock absorbing spacer assembly     22  resilient contact     22 H hole in resilient contact  22       22 GH guide hole in resilient contact  22       31  curling arm of resilient contact  22       32  ear of resilient contact  22       40  spring     41  lock ring     42  lip seal     51  outer member of tail cap     52  thread of member  51       53  knurl     54 F female spline     55  spring contact     57  central bore     61  inner member of tail cap     62  thread of member  61       64 M male spline     65  battery can engaging surface     100  battery     100 ( 1 ) first of two batteries in a series configuration     100 ( 2 ) second of two batteries in a series configuration     102  can     102 BC bottom surface of can  102       1020 C outer cylindrical wall of can  102       102 TC top surface of can  102       102 W battery wrap     103  positive cap with nipple     104  cathode powder     105  porous separator     106  anode powder     107  negative collector pin or anode current collector     109  plastic cap or grommet     110  electrical insulator     111  anode cap     112  vent mechanism     202  shock absorbing material     301  modified shock absorbing spacer     302  spring     303  tail cap   
 
         [0071]    Generally speaking, when two or more cylindrical batteries are held in a series configuration in a battery compartment, a top surface of each of the batteries has a nipple contact while the bottom surface of each of the batteries has a generally flat surface, and the top nipple contact is traditionally a positive or cathode contact while the bottom flat contact is traditionally a negative or anode contact. The battery compartment which holds the batteries in a series configuration traditionally has a top contact against which a first battery in the series is loaded and a compression spring that serves both as an electrical contact for the last battery in the series (hereinafter the terminal battery) and as a biasing means so as to keep the batteries in series held in electrical contact by biasing the bottom flat contact of the terminal battery toward the top contact. 
         [0072]    While the present invention is not limited to use with flashlights, and is applicable to any device with a battery compartment in which two or more batteries are held in a series configuration, the present invention will hereinafter be described and illustrated, for ease of understanding, by reference to only one specific device—a flashlight, examples of which are described in U.S. Pat. Nos. 6,361,183 and 8,366,290, the disclosures of which are specifically incorporated by reference herein. 
         [0073]    In a flashlight  1  the terminal battery is the last battery which is inserted into barrel  11  of the flashlight and the terminal battery is biased toward head  12  of the flashlight, which contains light source  12 , by a compression spring included in a tail cap  14  which seals off the barrel after the batteries have been inserted and the tail cap is screwed on and into place. 
         [0074]    While it is traditionally the case that the bottom flat contact of a first battery in a series configuration (which is inserted into a flashlight barrel before the next or second battery in a series configuration) is in both physical and electrical contact with a top nipple contact of the second battery in the series configuration, in accordance with one aspect of the present invention, such physical contact is prevented by a shock absorbing spacer inserted between the first and the second batteries in the series configuration. 
         [0075]    In an especially preferred embodiment of the present invention, a shock absorbing spacer  2  is configured as a disc which has a circular outer cross section which is of substantially the same diameter as the diameter of the two cylindrical batteries it is inserted between and an inner cross section which is of substantially the same diameter as that of the bottom surface  102 BC of the first battery and/or the top surface  102 TC of the second battery. It is especially preferred that shock absorbing spacer  2  have a thickness sufficient so as to keep the top nipple contact of the second battery in the series configuration from coming into contact with the bottom flat contact of the first battery in the series configuration, even when the flashlight is subjected to extreme shock, such as, for example, being dropped from a distance of several meters, or more. Accordingly, the thickness of the shock absorbing spacer should be greater than the height of the nipple of the top nipple contact, and take into account variations in such height in various batteries, as well as any compression of the shock absorbing spacer when it is performing its shock absorbing function under anticipated or desired performance criteria. The shock absorbing spacer can be made of any material that absorbs shock, such as energy-absorbing plastic or rubber, and it is especially preferred that the material be a cushioning material that absorbs a proportion of the kinetic energy arising when the flashlight suffers impact or is dropped, while still having sufficient recovery that the shock absorbing spacer will continue to function over time. 
         [0076]    Because shock absorbing spacer  2  keeps the top nipple contact of the second battery in the series configuration  100 ( 2 ) from coming into contact with the bottom flat contact of the first battery in the series configuration  100 ( 1 ), the two terminals must be electrically connected, and, in an especially preferred embodiment of the present invention, this is done by at least one resilient contact held by the shock absorbing spacer in a shock absorbing spacer assembly  20 , and the electrical contact with the top nipple contact is made with the base below the nipple, or outer diameter of the nipple (less preferably), but not the top surface of the nipple, as illustrated in  FIG. 25  in which shock absorbing spacer  2  has a thickness of Y whereas the distance between the top nipple contact of the second battery  100 ( 2 ) and the bottom flat contact of the first battery  100 ( 1 ) is X. The reason it is especially preferred that the at least one resilient contact not contact the top of the nipple is that reliance on such contact would mean that shock absorbing spacer  2  would need to be thicker so that a shock would not allow energy to be passed from the nipple through the resilient contact to the bottom flat contact. 
         [0077]    The at least one resilient contact can take on many different forms, some preferred embodiments of which are illustrated in  FIGS. 4, 8, 12, 16, 18, 20 and 22 . 
         [0078]    In  FIG. 4 , resilient contact  22  is formed from stamped metal with a plurality of holes  22 H, two guide holes  22 GH, and a curling arm  31 . Two mirror imaged contacts  22  are mounted opposite of each other (see  FIG. 3 ), with their holes  22 H and guide holes  22 GH aligned, and then shock absorbing spacer  2  is molded so that its material fills holes  22 H but leaves guide holes  22 GH unfilled, for later use in assembly, to form shock absorbing spacer assembly  20 . 
         [0079]    In  FIGS. 8, 12 and 16 , a single resilient contact  22  is formed from stamped metal, but multiple ears  32  are bent in opposing directions as illustrated in  FIGS. 7, 11 and 15 , respectively, and the ears of the different embodiments have different configurations. A shock absorbing spacer  2  is molded around the single resilient contacts  22  to form the different embodiments of shock absorbing spacer assembly  20  illustrated in  FIGS. 6, 10 and 14 . 
         [0080]    In additional embodiments, resilient contact  22  can be a spring, examples of shapes of which are illustrated in  FIGS. 18, 20 and 22 , and such springs can be secured within shock absorbing spacer  2  by molding to form shock absorbing spacer assemblies as illustrated in  FIGS. 19, 21 and 23 , respectively. 
         [0081]    Shock absorbing spacer assemblies  20  can easily be dropped in between batteries as batteries are being loaded into a barrel  11  of a flashlight  1 ; one shock absorbing spacer assembly should be inserted between every two batteries; accordingly, a flashlight having two batteries in series will use one shock absorbing spacer assembly between the two batteries; a flashlight having three batteries in series will use two shock absorbing spacer assemblies between the first and second, and the second and third batteries; a flashlight having four batteries in series will use three shock absorbing spacer assemblies between the first and second, the second and third, and the third and fourth batteries, and so on, so that the number of shock absorbing spacer assemblies used in a barrel will equal one less than the number of batteries arranged in a series configuration. In view of the ease of such assembly, it is easy to see why it is especially preferred that shock absorbing spacer  2  and resilient contact  22  form a single assembly; however, resilient contact  22  could also be detached from shock absorbing spacer to accomplish the same functional purpose, albeit with the need for a more difficult assembly process. 
         [0082]    Use of shock absorbing spacer assemblies  20  between two batteries in a series arrangement allows energy imparted during a shock to be absorbed by the shock absorbing spacer assemblies and also imparts substantially all of the shock between bottom surface  102 BC of can  102  of the first battery and top surface  102 TC of can  102  of the second battery in a series arrangement, rather than imparting shock to either bottom flat contact  111  of the first battery or top nipple contact  103  of the second battery. 
         [0083]    In another aspect of the present invention, a terminal end shock absorber is positioned so that the terminal end of a terminal battery in a series configuration will be cushioned by the terminal end shock absorber when a force is applied to the series configuration causing the two or more cylindrical batteries to move toward a terminal retaining member (which is a tail cap  15  in flashlight  1 ). 
         [0084]    In some situations, it may be possible to use a shock absorbing spacer  20  as a terminal shock absorber, depending upon how electrical contact is made with a tail cap, how the tail cap fits into a closed electrical circuit, and how much space there is between bottom flat contact  111  of the terminal battery and its contact point within the tail cap. In an especially preferred embodiment of the present invention, a specially designed tail cap assembly is used to provide a terminal end shock absorber. 
         [0085]    Because many different devices make contact with the terminal end of a terminal battery in different ways, even in one device category, such as a flashlight, it is worth noting that sometimes a strong spring is used to make such contact; however, if one is designing a particular device, especially where cylindrical batteries are inserted into a cylindrical tube, one way to minimize the amount of stress that might be applied to the terminal end of the terminal battery is to insure a snug fit so there is less room for the batteries to move in the event of extreme shock. 
         [0086]    One of the reasons why batteries may not enjoy a snug fit is variations in tolerance and production specifications/actual manufactured dimensions of batteries. As more batteries are aligned in a series configuration, there is a greater possibility of cumulative variations. In accordance with one aspect of the present invention, a snug fit is created by the combination of eliminating variations between pairs of batteries with a spacer (which can either be a shock absorbing spacer, as already disclosed, or a non-shock absorbing spacer having the same construction except for the use of a non-shock absorbing material) and then insuring a snug fit by creating a snug mechanical fit at the bottom surface of the can of the terminal battery. Use of spacers between adjoining battery terminals helps cancel variations in dimensions of the batteries because variations in positive cap  103  or anode cap  111  are no longer important since the spacer is held between bottom surface  102  BS of the first battery and top surface  102 TC of the second battery, and the width of the spacer is greater than the nipple of positive cap  103 . Accordingly, when a snug fit is created at bottom surface  102 B of the terminal battery, that snug fit will ensure that the cans of the batteries in the series configuration, with spacers between each pair of batteries, create a solid continuous length of material in which no meaningful force is applied to the battery terminals between two adjoining batteries while the terminal end of the terminal battery is retained at its can, rather than at its anode cap. 
         [0087]    One especially preferred embodiment of a device which creates a snug fit for the terminal end of a terminal battery is a mechanical contact that can be tightened against the bottom surface  102  of the terminal battery until a snug fit is obtained, and one example of such a device is disclosed in  FIGS. 26-32 , which is especially useful for the device category of a flashlight, in which a two piece tail cap is provided in which an inner member  61  of the tail cap  50  can be driven by an outer member  51  of tail cap  50  to screw into flashlight barrel threads  11 T so that bottom surface  102 BC of the terminal battery is held snugly by battery can engaging surface  65  of inner member  61  as illustrated in  FIG. 33 . In this especially preferred embodiment, mating splines are used to illustrate one mechanical driving mechanism; however, this embodiment is meant to be illustrative, rather than limiting, and any other suitable driving mechanism could also be used in alternative embodiments within the scope of the present invention. Returning to  FIG. 33 , inner member  61  is driven by engaging female splines  54 F in outer member  51  of tail cap  50  with male splines  64 M of inner member  61  and then using outer member  51  to screw inner member  61  into position; once inner member  61  is fully screwed into position, female splines  54 F and  64 M are disengaged and threads  52  of outer member  51  are then screwed into flashlight barrel threads  11 T to secure outer member  51  to barrel  11  as illustrated in  FIG. 34 . It is especially useful if a lock ring  41  is used to secure outer member  51  (which has a lip seal  42 ) to inner member  61  (see  FIGS. 33 and 34 ); inner member  61  and lock ring  41  can be designed so that lock ring  41  will not be removable once it is in place or so that it can be removable with a certain amount of force. Because the two piece construction of tail cap  50  allows battery can engaging surface  65  to snugly hold bottom surface  102 BC of the terminal battery (and it is especially preferred that battery can engaging surface  65  engage all or substantially all of bottom surface  102 BC, but not anode cap  111 ), an electrically conductive spring  40  may or may not be required, depending upon whether bottom surface  102 BC is insulated, such as by a battery wrap  102 W; but, even if it is required, conductive spring  40  need not be a strongly compressed spring and can have a minimum contact force (of around 200 grams or 0.44 lbs.)—just enough to ensure electrical contact, but not so much that it will provide a mechanism for imparting a damaging force to the terminal end of the terminal battery in the event of extreme shock. (Springs used in tail caps of prior art flashlights to create a biasing means forcing the batteries toward the top contact could have a much higher contact force, on the order of 10 lbs. or more.) Spring  40 , as illustrated in  FIG. 33 , can be secured by spring contact  55 . 
         [0088]    One way of minimizing any potential damaging force that spring  40  might impart to the terminal end of the terminal battery in the event of extreme shock is to minimize its length and strength.  FIGS. 35-41  illustrate an alternative embodiment of a two piece tail cap in which a central bore  57  in which spring  40  is held is minimized so that a shorter spring can be used for ensuring electrical contact between the terminal end of the terminal battery and the tail cap. 
         [0089]    The two piece tail cap construction described so far can also be used in devices that utilize rechargeable battery packs, an example of which is a NiMH battery for the Mag Charger® LED flashlight. In such a device, multiple rechargeable batteries are wrapped together in a snug casing, which is electrically insulating, so the terminal end of the terminal battery extends out of the casing, and a button end of a first battery also extends out of the casing, but the other ends of the batteries held in series are held tightly together inside of the battery wrap. In such a device, while shock absorbing spacers  2  might be used inside of the casing when the battery pack is manufactured, it is not possible to use shock absorbing spacers  2  with existing battery packs without destroying the battery wrap, which is not desirable; however, the two piece tail cap construction already described will still prove useful with such battery packs. 
         [0090]    The two piece tail cap construction already described can also be modified to provide a shock absorbing spacer  202  that makes contact with bottom surface  102 BC of the terminal battery, and  FIGS. 35-38  illustrate one example of how such a shock absorbing spacer can be provided. In this especially preferred embodiment, shock absorbing spacer  202  is held or mounted to inner member  61  of tail cap  50 , shock absorbing spacer  202  is configured to absorb a primary impact force imparted between it and bottom surface  102 BC of can  102 , and shock absorbing material  202  may be similar or identical to that used in shock absorbing spacer  2 . Such construction is also especially preferred for use with rechargeable battery packs that do not utilize shock absorbing spacers between batteries contained with the battery packs. 
         [0091]    Because there are millions of flashlights already in use, it is also desirable to provide a kit and method by which such existing flashlights can benefit from the teachings of the present invention. 
         [0092]    As already noted, flashlights in use today typically have a compression spring that serves both as an electrical contact for the terminal battery and as a biasing means so as to keep the batteries in series held in electrical contact by biasing the bottom flat contact of the terminal battery toward the top contact. This means that the compression spring is usually fairly strong, and it exerts a strong compressive force against bottom flat contact  111  of the terminal battery (not just to maintain electrical contact, but also to keep the batteries biased toward the top contact); however, when the battery receives a shock, movement of the batteries against the strong compression spring causes the spring to further compress, applying even greater compression force against bottom flat contact  111 . By contrast, the present invention seeks to minimize the compressive force applied against bottom flat contact  111  of the terminal battery and to rely upon a terminal end shock absorber to both absorb some shock as well as transfer energy through bottom surface  102 BC of can  102  of the terminal battery, rather than through bottom flat contact  111 . 
         [0093]    One way a flashlight can be retrofitted with a terminal end shock absorber in accordance with the present invention is to replace an existing tail cap assembly with its compression spring with a new tail cap assembly  200  such as is illustrated in  FIGS. 39 and 40 . Replacement tail cap assembly  200  utilizes a shock absorbing material  202 , a tail cap resilient contact  201  and a tail cap  203 . Shock absorbing material  202  is configured to absorb a primary impact force imparted between it and bottom surface  102 BC of can  102  of the terminal battery while the tail cap resilient contact is configured to absorb a secondary impact force imparted between it and the flat contact of the terminal battery, wherein the secondary impact force is substantially less than the primary impact force. While tail cap resilient contact  201  might be configured similarly to resilient contact  22 , it may also be configured as a small compression spring, which may be more suitable for use in a replacement kit in which all of the components of the flashlight have not been designed so as to take advantage of use of one or more shock absorbing spacer assemblies and a terminal end shock absorber. Shock absorbing material  202  may be similar or identical to that used in shock absorbing spacer  2 . 
         [0094]    An alternative embodiment to that shown in  FIGS. 39 and 40  is to utilize a shock absorbing spacer  2 , as already disclosed, which is modified as illustrated in  FIGS. 41 and 42 . In this embodiment, the contacts with the terminal end of the terminal battery (or the terminal end of a rechargeable battery pack) of modified spacer  301  remain the same as already described, but the other contacts are replaced with a spring  302  which makes electrical contact with tail cap  303 . 
         [0095]    While the invention has been described herein with reference to certain preferred embodiments, those embodiments have been presented by way of example only, and not to limit the scope of the invention. Additional embodiments will be obvious to those skilled in the art having the benefit of this detailed description. For example, because the terminal end shock absorber does not need to separate two terminals of batteries in series, but a terminal end of a terminal battery from a tail cap, the terminal end shock absorber might be constructed to provide shock absorption through mechanical means, or means other than using a shock absorbing material similar to that of shock absorbing spacer  2 ; thus, for example, a tail cap might be designed to include one or more mechanical pistons that compress air within one or more enclosed spaces with appropriate pressure relief. 
         [0096]    Accordingly, still further changes and modifications in the actual concepts descried herein can readily be made without departing from the spirit and scope of the disclosed inventions as defined by the following claims.