HK1199798B - Heated insoles - Google Patents

Description

Heated insole

RELATED APPLICATIONS

This application is based on and claims priority from U.S. provisional patent application serial No. 61/581,782 filed on 30/12/2011 and U.S. provisional patent application No. 61/594,043 filed on 2/2012, the contents of which are incorporated herein.

Background

The present invention relates to improvements to heated insoles for footwear worn, particularly for hiking, cycling and skiing shoes, and even for ordinary shoes if the wearer's foot is cold.

Various systems have been designed and employed over the years to provide additional medial heating of the footwear when the footwear is used in an outdoor environment. One example of such a prior art system is shown in US patent publication US2009/0013554, which relates to a wireless system in which a signal is sent to control a heater in an insole.

Over time, fixed hard-wired systems (such as the one shown in U.S. patent #4,665,301) have emerged in which a heater is plugged into a wall socket to provide heat to an insole used during the day. Which can be charged by a suitable charging system to reheat the heated insole in order to provide adequate warmth to the user.

These systems typically result in the placement of an electric heater at the bottom of the insole and various non-conductive foam materials in the insole. A limitation of current conventional designs is that a good portion of the heat is not provided to the upper portion of the insole, which is in closer contact with the wearer's foot.

Flat lithium ion batteries have been integrated as the battery that provides power to the insole, as opposed to having battery power on the outside of the shoe as previously provided for heating the insole.

Lithium ion battery chargers are typically made of two parts:

a power supply that converts line AC to low voltage DC; and

an Integrated Circuit (IC) that receives the low voltage DC, monitors the battery state of charge, and delivers the appropriate current and voltage to fully and safely charge the battery for heating the heated pads and insoles.

Heretofore, insoles with built-in lithium ion batteries supplied charger power as wall-mounted devices and smart charging circuits located in the insoles. Such an arrangement exposes the charging components to the mechanical pressure and heat of use as the footwear is worn. Any failure of the charging means results in the entire product being unusable.

It is an object of the present invention to provide an improved heating system for an insole of a shoe.

It is another object of the present invention to provide heat to the wearer more efficiently during ordinary use.

It is another object of the present invention to provide an improved lithium battery system in which the smart circuit components are located on the outside of the shoe.

It is another object of the present invention to provide a more efficient and economical system for heating insoles.

It is another object of the present invention to more efficiently place the heater in the insole to provide heat more directly to the foot of the wearer.

It is another object of the present invention to provide a more efficient and economical battery charging system that is more easily and widely used.

Other objects, advantages and features of the present invention will become more apparent from the following description.

In accordance with the gist of the present invention, the above object is achieved by separating an Intelligent Circuit (IC) for charging a rechargeable lithium battery from the lithium ion battery itself. This may be achieved by placing the IC charging circuit in the AD/DC plug adapter assembly or by making the IC charging circuit assembly as a module located close together and connected to the AC/DC converter.

Since the IC is a relatively expensive component of the lithium battery pack, eliminating the IC from the physical wear and tear that is commonly encountered and integrated with the battery to be charged enables the expensive pack to extend its life, reduce the likelihood of failure and ensure that only the lithium battery is replaced when necessary without replacing the entire Integrated Circuit (IC) lithium battery pack.

Furthermore, this is achieved by additionally relocating the heater in the insole from a substantially bottommost position furthest from the user's insole to a position closer to the user's foot so as to provide more efficient heat directly to the user, thereby reducing energy consumption and heating the area more efficiently and quickly. The prior art insole has an EVA foam layer of approximately 5mm thickness located over the heater. The new structure compresses the EVA foam to no more than 2 or 3mm, then adds an additional conductive layer over the cells and an additional insulating layer between the foot and the bottom of the shoe to improve thermal conductivity to the wearer's foot.

These improvements are described in more detail below with reference to the drawings.

Drawings

Fig. 1 is a block diagram of Intelligent Circuit (IC) components located outside of a lithium battery located in an insole.

Fig. 2 is a schematic diagram of an IC component for charging a lithium battery as shown in fig. 1.

Fig. 3 is a sectional view through showing an insole of a prior art shoe.

FIG. 4 is another cross-sectional view similar to FIG. 3 but showing the heater being more effectively positioned to heat the user's insole.

FIG. 5 is another cross-sectional view of an insole similar to FIG. 4 showing additional embodiments.

FIG. 6 is a perspective view of another embodiment of an insole construction similar to FIG. 5.

Detailed Description

Fig. 1 is a block diagram of the present invention of an AC to DC converter indicated only as DC in block 10. Such an AC to DC converter is plugged into a 120V wall outlet or any other suitable AC wall outlet to provide a DC output. The output of the DC converter 10 is supplied to charger Intelligent Circuits (ICs) 12 and 14, the intelligent circuits 12 and 14 including the capability to: receives the low DC voltage generated by the converter 10, monitors the battery state of charge and delivers the appropriate current and voltage to fully and safely charge the battery. A charging LED driver 16 is provided to illuminate the LED 18 as the battery is charged. The outputs of the charger intelligence circuits 12 and 14 are supplied to batteries 20 and 22, respectively, the batteries 20 and 22 being located in the insoles, respectively.

Batteries 20 and 22 are located in the insole and two batteries are provided for a pair of insoles for a pair of shoes. Cables or conductors 24 and 26, respectively, are provided as outputs of the IC circuit terminated in a standard plug of a socket included in the shoe to be heated. The IC circuits 12 and 14, the LED driver 16, and the LEDs 18 may each be included in a single housing that is directly connected to the AC-to-DC converter 10 or integrally formed in the AC-to-DC converter 10.

Fig. 2 is a more detailed schematic diagram showing the electronic components of the block circuit shown in fig. 1.

The DC input power is provided at the AC/DC converter and is shown in fig. 2 as the sign +, which is typically + 5V. The power delivered by capacitors 28 and 30 ensures that the power is flat and does not carry any short narrow pulses of voltage. Torex components 32 and 34 are integrated lithium ion battery charging ICs. One such IC is Torex XC6801A4 PR-G. The purpose of these devices is to monitor the status of the insole battery, which is located separately from the PCB, and the status of the insole battery in the heated insole itself. The ICs 32 and 34 are each intelligent devices that check the charging characteristics of each battery and adjust their output voltage to match the current profile (profile) that matches the capacity of the battery and the chemistry of the battery. This output is pin 36 of ICs 32 and 34, respectively.

The battery condition is displayed to the user via pin 38 of ICs 32 and 34, and this pin is an open collector (opencollector) type output and is pulled down during the charging state. Power is supplied to pin 38 through resistor 31. The low charge then turns on P-channel FET Q1-B, designated as number 40, which in turn turns on the next P-channel FET Q1-A, designated as 42. The low level on Q1-a 42 allows current to flow from the cathode of LED 44, which causes the LED to emit light, and receives its power through resistor 46.

Both ICs 32 and 34 share this connection to Q1-B40, as it is important that either of the charger devices 32 or 34 be able to activate the charge LED indicator when the battery needs to be charged, or that only one of the charger devices 32 or 34 do so. Once both devices determine that each battery is fully charged, they assume a high level on their output pins 36, which is then pulled to + Power via resistor 46.

The high on this node then deactivates Q1-B40, which in turn deactivates Q1-A, causing current from LED 44 to be interrupted and the LED to be extinguished. The extinguished LED indicates that charging of both insole batteries is complete.

The components 48, 50 and 52 form an RC time constant such that small pulses appearing at the outputs of the ICs 32 and 34 during charging are ignored and only the DC status indicates a change in LED status.

Capacitors 54 and 56 are DC storage capacitors such that when the charger is not connected to the battery, the capacitors are charged via ICs 32 and 34 to the point where both ICs 32 and 34 deem the battery present and fully charged, thus turning off the LEDs when no battery is connected to the system. This is achieved because it is desirable for the LED to be in an "off" state when the battery is not connected, an "on" state when the battery is connected and charged, and an "off" state again when the battery is fully charged.

FIG. 3 is a cross-sectional view of prior art footbed 60 having a black, non-woven bottom layer 62 and an insulating foam layer 72 with PCB 63 disposed thereon. The PCB board controls the heater 68. The prior art IC64 circuit controls the rechargeable battery 20, which in combination with the PCB board circuit 63 controls the heater 68 through conductor 70 to heat the insole. The use of PCB circuitry to control the heater 68 is described in U.S. patent 8,074,373 to Macher et al, the contents of which are incorporated herein.

Although prior art fig. 3 is a single unit 66(20 and 64) of combined lithium and Intelligent Circuit (IC) integration, it should be understood that the battery 20 included in the insole may be separate from the IC circuit 64. The electrical conductors 24 and 26 between the IC circuits and the socket in the footwear will carry a signal to charge the battery 66 to control the heater 68 in conjunction with the PCB board 63.

The combination of components in the improved location for the heater mat in the insole also enhances the overall heating capacity and overall efficiency of the invention when utilized with the separate IC circuits on the outside of the shoe shown in fig. 1 and 2 described above.

The prior art construction in FIG. 3 has an EVA foam footbed member 72 that is located on top of the footbed structure previously described, such that heat is generally dissipated from heater 68 through foam 72 up to the bottom of the ball of the foot (not shown) located on top of EVA foam member 72. The foam material of the prior art structure has a thickness of about 5mm that is compressed only slightly, so that the thickness of layer 72 is about 5mm when the shoe is worn.

A first embodiment of a modification of the prior art is shown in fig. 4, which positions the heater 68 closer to the ball of the foot on top of the foam 72. In this embodiment, the recess 74 is EVA foam 72 formed over the heater 68 to minimize foam just under the ball of the foot in the area of the heater 68. The foam 72 is compressed to 2-3mm and preferably 2 mm. Compressing the EVA foam to no more than 3mm makes it denser and more thermally conductive than the prior art, thereby transferring heat from the heater 68 to the foot. Additionally, a separate insulating member 76, approximately the size of the heater 68, is added between the surface 62 and the heater 68 to ensure that heat is directed upward. The reason this additional insulating member can be added is the space saved by compressing the foam layer 72 to 2-3 mm. Thus, the thickness of the foam 72 between the heater 68 and the ball of the foot is materially reduced, while the insulation 76 beneath the foam 72 reduces the amount of heat lost downwardly from the heater 68.

FIG. 5 is another embodiment of a heater pad insole construction that may be provided separately or in combination with the embodiment of FIG. 4. An additional layer of insulation 78 is provided on top of the bottom black non-woven layer 62 and below the heater 68 to further prevent heat from the heater 68 from escaping down to the bottom of the insole. Because of the reduced thickness of the foam layer 72, space is provided for the layer 78 to substantially extend the length of the footwear. In this regard, a more efficient insole heating system is provided by further preventing heat from escaping, allowing more heat to reach the foot upward.

FIG. 6 is a perspective view of another embodiment of a system for delivering more heat to the foot in a heated insole. The prior art single EVA foam pad 72 is modified to be formed in two sections, a front section 80 and a rear section 82. The portions 80 and 82 are unitary and have a hole or recess 83 between the front and rear portions. The conductive pad 86 fits in the hole 83. Pad 86 is a thermally conductive rubber or rubber-like material. It is 1 or 2mm thick. Heater 68 is located in hole 83 and below pad 86. The bottom insulation base layer 78 (as shown in fig. 5) has a heater 68 placed on top of the base layer 78 in a recess 83. Conductive pad material 86 is located on top of heater 68 so that heat from the heater is carried directly to the ball of the foot and dissipation of heat escaping downwardly from heater 68 is prevented by insulating layer 78. This configuration allows more heat to reach up to the bottom of the ball of the foot in a more efficient manner, thereby reducing the power drain of the battery 66. The foam 72 includes a small portion labeled 72a in fig. 6.

The preferred embodiment of the present invention places the heater 68 within 2mm of the foot side of the insole.

A more consumer friendly product can be provided by having a turbine mode (turbo) that provides an initial burst of high heat when the heater 68 is initially turned on. Furthermore, the turbine mode may be repeatedly activated manually by a user or automatically in the system. When a remote system is employed to control the heater 68, the remote transmitter when activated may initiate turbine mode for the system.

As a further improvement, the electronic system on the PCB board may also include cycling heat control between high and low heat to more efficiently utilize energy and maximize user comfort.

For improving the thermal conductivity of the foam EVA layer, the foam may be compressed such that it is denser to improve thermal conductivity or a rigid plastic may be used instead of foam to provide both insulation and thermal conductivity, thereby allowing heat to reach the bottom of the wearer's foot more efficiently.

The present invention has been described in relation to improving the overall efficiency, safety and economy of providing heated insoles for footwear intended primarily for outdoor use. One aspect of the present invention is to improve the transfer of heat to the foot of the wearer so as to reduce wasted heat and more efficiently utilize the output of the heated pad. This reduces power consumption and improves the life of the heating unit and battery operation times as a whole.

Furthermore, an important aspect of the present invention is to minimize waste by separating the smart circuit from the lithium battery (which is different from the prior art structure in which such elements are combined into a single unit in the insole). By separating the IC circuit and the battery, significant improvements are achieved in the system.

An IC charging function different from merely making an electrical connection to the battery is performed on the outside of the insole. Electronic components are placed in the power supply plugged into a socket of a wall or in the cable between the power supply and the battery, with intelligence to determine the state of charge of the battery and to fully and quickly charge the battery in response to the correct voltage and current.

The advantages of such a system are:

remove the charging component from the insole, where the charging component is subject to heat build-up, and the repeated mechanical stress of walking means that the charger will last longer.

Charger circuit failure can be repaired by replacing the charger alone, rather than the entire product.

Fewer electronic components in the insole structure means that the insole will last longer.

Easy upgrade, faster, longer lasting charge, etc., which can be achieved by changing the charger. Previously, the entire product including both insoles and the charger power supply needed to be upgraded.

Improved energy efficiency: an LED indicates the charging status, and the LED is turned off when the insole is not being charged.

Larger charger PCB area allows better ESD (electrostatic discharge) protection and insulation.

The external charger can be modified for a wide variety of AC and DC input voltages for more widespread global use.

It should be noted that the preferred embodiments are described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly and legally equivalent.

Claims (11)

1. A system for charging an internal battery disposed in an insole for heating an insole of a shoe, the system comprising:

an internal battery located within the insole;

a socket connected with the internal battery; and

an external smart circuit located on an outside of the insole for controlling charging of the internal battery by monitoring a state of charge of the internal battery and adjusting a voltage delivered to the internal battery based on the state of charge of the internal battery,

wherein the external smart circuit has an input for receiving a DC input voltage;

wherein the external smart circuit comprises an output electrical conductor for conveying a charging voltage and current to the internal battery; and is

Wherein the receptacle is connected to the output electrical conductor and the internal battery to communicate the charging voltage and current to the internal battery.

2. The system of claim 1, wherein the output electrical conductor communicates monitoring information from the internal battery to the external smart circuit.

3. The system of claim 1, wherein the DC input voltage is generated by an AC-to-DC converter and the external smart circuit is formed as an integrated component with the AC-to-DC converter.

4. The system of claim 1, wherein the output electrical conductor comprises two electrical conductors, one of the two electrical conductors for one of a pair of shoes and the other of the two electrical conductors for the other of the pair of shoes.

5. The system of claim 1, wherein the system for charging further comprises an LED to indicate when the internal battery needs to be charged.

6. The system of claim 1, wherein the internal battery is connected to a heater to provide heat, wherein the insole comprises a foam layer located between the internal battery and a foot of a wearer of the footwear.

7. The system of claim 6, wherein the thickness of the foam layer between the heater and the ball of the foot is approximately two millimeters when the foam in the foam layer is compressed.

8. The system of claim 6, wherein the thickness of the foam layer between the heater and the ball of the foot is approximately three millimeters when the foam in the foam layer is compressed.

9. The system of claim 6, wherein the insole comprises an insulating layer located below the foam layer.

10. The system of claim 6, wherein the foam layer has a front portion and a rear portion with an aperture or recess therebetween, and a thermally conductive layer is located in the aperture or recess, the heater being located below the thermally conductive layer.

11. The system of claim 10, further comprising an insulating layer located below the heater.