US 20040149797 A1
A battery pack retention system useful for releasably securing an external battery pack to a user includes a battery pack having a first surface feature that secured, but releasably, connects to a second surface feature on a securing device. The securing device has gripping means to secure the battery pack assembly to a ski boot or elsewhere on the user. The releasable connection between the battery pack and the securing device provides the system with flexibility to provide different types of securing devices for enhanced user comfort and convenience.
1. An external battery pack securing system that comprises, in combination:
(a) a battery pack within a rigid shell having front, back, top, bottom, and lateral surfaces, wherein a first surface feature is formed into at least one of said surfaces; and
(b) a securing device exhibiting (i) a second surface feature that can be secured to said first surface feature in a releasable connection and (ii) a gripping means that allows the securing device to be grip or be secured about the user's person or gear.
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 Battery pack securing systems according to the invention include one or more batteries enclosed within a rigid housing that exhibits a first shaped feature on at least one of the sides of the enclosure. A securing device exhibits a corresponding second surface feature for engaging and retaining the first surface feature on the battery pack in a secured, but releasable, connection and a gripping means that allows the securing device to be secured on or about the user or the user's gear. This combination provides for a variety of securing devices to be useful with a single battery pack for use in a variety of situations.
 As used herein, the term “external” connotes a battery or battery pack that is secured or attached near the user but at a location remote from the heating element. A pair of wires, preferably in a flat ribbon, connects the battery pack to the heating element with suitable connectors. Connection wires are available in different lengths to accommodate attachment of the battery pack to footwear when using a heated insole system, to the user's wrist or arm when using heated glove inserts, or for securing the battery pack on the user's waist or other location.
 It will be understood that all relative orientation terms used herein refer to the orientation of the printing and controls on the battery pack as made by the manufacturer. For example, temperature controls on a first side of the battery pack and lettering on the batter pack that can be read when the controls are above the lettering makes the controls on the “top” surface of the battery pack.
 Battery packs according to the invention preferably include control circuitry and externally accessible controls for regulating and adjusting the current flow from the batter to the heating element. Such circuitry could be physically located almost anywhere in the device although a control board in a sealed battery pack device is preferred. Suitable control circuits include a deep discharge control circuit that detects the battery voltage against a predetermined minimum battery voltage and open the circuit to terminate the flow of current from the battery and thereby limit the degree to which the battery is discharged. A recharge control circuit would also detect the battery voltage against a predetermined maximum battery voltage, battery temperature, or a combination thereof and limit current flow when predetermined maximum levels had been reached. If desired, a battery voltage control circuit and a recharge circuit can be associated with each battery used in the system of the invention.
 A particularly preferred invention includes a first battery and a second battery sealed within a battery pack case. Each battery is made with a commercially available battery.
 The battery pack case has an external connection for a recharger plug or induction charging base. Regardless of its external details, the recharging energy supply electrically communicates to each battery through one or more circuit boards, preferably only one circuit board for the battery pack with connections for each battery, for control over the battery recharging process.
 Deep discharge control circuits are also preferably associated with each battery for control over the outflowing current by comparing the present battery voltage against a predetermined minimum voltage. When the minimum voltage is exceeded, the circuit terminates electrical flow through that battery to prevent a level of discharge that exceeds safe margins for recharging of the battery. The deep discharge circuits also prevent an imbalance in the degree to which each battery in a battery pack becomes discharged, i.e., one battery does not become overly depleted while the other battery retains capacity.
 The deep discharge prevention and overcharging control circuits used in battery packs of the present invention are intended to provide safeguards against unbalanced discharge and recharging states. The deep discharge circuits will prevent one battery from becoming so deeply discharged that it has difficulties in recharging while the other battery or batteries in the battery pack have capacity. The recharge control circuits prevent the unused batteries from becoming overcharged as a deeply discharged battery has not been fully recharged. Suitable trickle charge circuits could be included to introduce low levels of charging current so as to maintain fully charged batteries.
 Additional control circuitry could also provide a temperature sensor at the heating element with appropriate controls to keep the output temperature within specified limits and shutoff circuits at the battery for minimum and/or maximum current flow. Multiple settings would provide flexibility in heating to accommodate users with differing sensitivities to cold in their extremities (e.g., hands and feet). The maximum temperature and current limiting circuitry will afford a measure of safety against accidental or unintended electrical situations that might lead to burns.
 One or more batteries and any circuit board are preferably disposed within a case having appropriate electrical contacts or connection for recharging the battery or batteries inside as well as for providing current flow out through the connector, such as to the heating element. Optional additional circuitry on the board is associated with a multiposition switch on the outside of the battery pack case that controls the current flow out of the battery for adjustable levels of heating output at the heating element.
 As noted above, the battery pack enclosure is preferably molded with a rigid plastic and is formed to exhibit a first surface feature that can be securely, but releasably, connected to a corresponding second surface feature on the securing device. The first surface feature can protrude away from the battery enclosure (a male surface feature) or be formed into the battery enclosure (a female surface feature). When the first surface feature extends from the battery case, the corresponding second surface feature is preferably a female opening, slot, groove or equivalent opening that extends into the body of the securing device, and vice versa.
 Preferred first surface features include cross sectional shapes and configurations with an undercut shape that provides a gripping surface. A preferred example is a dovetailed groove or ridge formed into at least one of the sides, bottom, front, or back of the battery pack. Alternative shapes as the first surface feature include a “T” shaped ridge or slot or threaded surface. In general, it is often preferable to form the corresponding surface features in such a manner that the battery pack lies as flush as possible to minimize unintended impact or deflection forces that might break the surface features used to secure the battery pack to the securing device.
 Suitable securing devices for use in the invention have a second surface feature that mate with the first surface feature on the battery pack in a secured, releasable connection and a gripping means. Such releasable connections can include a laterally deflectable arm that moves laterally to allow the securing device to mate with the battery pack surface feature and deflect back into original position within a suitably shaped opening or depression in the battery pack when the securing device is fully mated and engaged with the battery pack. Release of the connection would be available by deflecting the armature out of the opening and disengaging the respective parts.
 Suitable gripping means include a variety of designs that grip, restrain, or otherwise engage an article. Preferably, the gripping means is able to engage an article by friction and become secured thereto by the influence of springs, straps, hook-and-loop fabrics, deflectable armatures, and the like. Preferred gripping means include spring steel clips and strap fastening brackets.
 The enclosed drawings provide additional information of certain preferred embodiments. The same reference numeral will be used to refer to the same structural feature on the various embodiments depicted.
FIG. 1 shows a battery pack 1 having a top 2, lateral sides 3, 4, bottom 5, front 6, and back 7. Dovetailed slot 8 with outwardly sloping lateral walls 9, 10 and retention depression 11 are formed in the back of battery pack 1 as a first surface feature that can be used to engage a matingly shaped securing device. Slot 8 should extend at least partially along the length of battery pack 1 and is preferably long enough so that the weight of the battery pack is supported by the top 12 of slot 8 and the rotational center of mass of battery pack 1 encourages secure engagement.
FIG. 2 depicts battery pack 1 with a dovetailed ridge 13 having outwardly sloping sidewalls 14, 15.
FIG. 3 depicts a battery pack embodiment having a “T”-shaped slot 16 in the back of battery pack 1. The lateral arms 17, 18 of the “T” engage with correspondingly shaped arms on a securing device.
 FIGS. 4-6 illustrate views of a securing device 20 having a dovetailed male panel 21 with outwardly sloping panel sidewalls 22, 23 as a second surface feature that matingly engages dovetailed slot 8. Deflectable arm 24 and tapered abutment stop 25 will deflect while panel 21 is inserted into slot 8 and rotate back into position when stop 25 enters depression 11. Bearing surface 26 then prevents disengagement of securing device 20 from slot 8 until stop 25 is urged out of depression 11. Top opening 27 between arm 24 and panel 21 should be sufficient to allow a rigid tool to be inserted therebetween so as to lift arm 24 out of depression 11 without damage thereto.
 Spring clip 28 is made with bent spring steel 29 having two opposing spring arms 40, 41. Lever arm 30 is secured to arm 40 of spring steel 29. Arm 41 is inserted into an appropriate slot 42 in panel 21 and secured in place with stop 43 that will extend thru opening 44 in arm 41 when fully inserted into slot 42.
 Spring steel 29 should have sufficient strength to secure the weight of battery pack 1 in position. Preferably, lever arm 30 is molded around one arm of bent spring steel and may include ergonomic finger depression 31. If desired, gripping surface 32 of panel 21 may be formed with ridges or other protruding surface contours 33 to enhance the gripping effectiveness of gripping surface 32.
FIGS. 7 and 8 illustrate a strap bracket 70 that uses screw hole 71 and strap 72 to secure the bracket to a ski boot (not shown). The design and details of such a bracket are generally similar to that shown in copending U.S. patent application Ser. No. 09/942,841, the disclosure of which is herein incorporated by reference. Briefly, strap bracket 70 generally includes a main plate 73, a mounting plate 74 having a dovetailed shape with inwardly sloping sidewalls 75, 76 dimensioned to fit within dovetailed slot 8 and support battery pack 1, and first and second support legs 77 and 78 for engaging strap 72. Main plate 73 includes front and back surfaces 79, 80. Front surface 79 is substantially planar and defines the plane of main plate 73 and bracket 70. Back surface 80 is generally curved with respect to the longitudinal axis of plate 73 as best seen in FIG. 8.
 Extending from main plate 73 are first and second co-axial, offset support legs 77 and 78. First and second slots 81 and 82 are defined between each of support legs 77 and 78, respectively, and first and second sidewalls 83 and so that slots 81 and 82 and support legs 77 and 78 are preferably generally parallel to the longitudinal axis of main plate 73. Strap 72 passes behind each of support legs 77 and 78 and in front of main plate 73.
FIG. 1 is an illustration of a battery pack having a dovetailed slot in the back surface.
FIG. 2 is a drawing of a battery pack having a dovetailed ridge extending from the back surface.
FIG. 3 is a sketch of a battery pack having a “T” shaped slot in the back surface.
FIGS. 4 and 5 depict a securing device having a male dovetailed ridge for engagingly mating with a dovetailed slot in a battery pack, such as shown in FIG. 1, and a gripping means that includes a spring-loaded clip. FIG. 5 also shows a deflectable arm retention mechanism for releasably mating the securing device and the battery pack.
FIGS. 7 and 8 show a strap bracket with a dovetailed ridge for connecting with a dovetailed slot in a battery pack, such as is shown in FIG. 1.
 The invention relates to systems for securing an external battery pack and associated electronics of an electrically heated insert sole to the a user.
 Many sports and activities are conducted outdoors under cold and possibly harsh conditions. Examples include snow skiing, hunting, ice skating, ice fishing, etc. Many occupations also involve exposure to similar conditions. In each circumstance, the body will respond to cold temperatures by directing blood flow to maintain core body temperature even though the extremities, hands and feet, may suffer discomfort.
 A variety of products have been sold as sources of warmth for the extremities that may be used in boots, mittens, and gloves. Some of the products rely on slow chemical reactions that produce a range of heat output based on exposure to oxygen. Such products can be made inexpensively but are bulky and require a certain minimum rate of air flow or volume of air for proper operation. Chemical heat sources are not well suited for use in form fitting ski boots and typically are not designed to be reusable once depleted.
 Another type of product relies on a battery current flowing through a resistive heat element to produce heat in the vicinity of the resistive element. Some products have a fixed current flow. Others have a variable rate of current flow. Both types of units, however, use batteries connected to the resistive element by a flat wire so that the battery pack is located outside the article of clothing. Battery packs for ski boots are often clipped on the back or outside of the boot by a spring clip or similar suitable attachment means. Copending U.S. patent application Ser. No. 09/942,841 filed on Aug. 31, 2001 entitled “Strap Bracket” is hereby incorporated by reference in its entirety. The battery packs for mittens and gloves are usually on the outside top of the hand.
 The wide variety of different uses for electrically heated warming systems are not well-served by a single, restrictive system for securing the required battery pack and associated electronics to the user. For example, products designed for rigorous use on ski boots require attachment systems that may not necessarily be optimal for use in fishing waders or with ice skates.
 It would be desirable to have a system for securing an external battery pack, with or without its associated electronics, to a user that allows the user to select from among a variety of alternative means for optimal comfort and convenience.
 It is an objective of the invention to provide a battery pack design and securing system that allows the user to select from among a variety of securing means for optimal comfort and convenience.
 In accordance with this and other objectives of the invention that will become apparent from the description here, external battery pack securing systems according to the invention comprise:
 (a) a battery pack within a rigid shell having front, back, top, bottom, and lateral surfaces wherein a first shaped feature (for example, a dovetailed slot) is formed into at least one of said surfaces; and
 (b) a securing device exhibiting (i) a second surface feature that can be secured to said first shaped feature (for example, a dovetailed ridge) in a releasable connection and (ii) a gripping means (such as spring-loaded clips, plates, and strap brackets) that allows the securing device to be grip or be secured about the user's person or gear.
 Securing systems according to the invention allow users to select from a variety of different ways to secure an external battery pack on or about their person, footwear, clothing, or gear in a manner that is most comfortable and convenient for the user. A releasable connection allows the user greater flexibility in using the same battery pack with one or more different heated devices.