PERSONAL HEAT CONTROL

Abstract: A personal heat control has a housing (4) accommodating a Peltier-effect unit (1), one or more batteries (15) and a timing switch (9) for selective energisation of the unit (1). The housing (4) is releasably attached to a part of a person's body, e.g. the wrist, by a strap (5) with a cooling surface cooled by the unit (1) in contact with the body part to enhance heat transfer between the person's body and the surrounding air for comfort and refreshment purposes when the unit (1) is energised.

Description: PERSONAL HEAT CONTROL This invention relates to personal heat control, and in this respect is concerned especially with devices to be worn on the person for effecting cooling, or warming, of the body. According to one aspect of the present invention there is provided a personal heat control device for a person ' s body, comprising a cooling surface and a heating surface thermally insulated from the cooling surface, a Peltier-effect unit for cooling the cooling surface and heating the heating surface, the Peltier-effect unit being accommodated in or on housing means connected to attachment means for attachment ofthe device to a part ofthe person's body with one of said surfaces in contact with the skin at said body part, and switch means for selective connection of the Peltier-effect unit to electrical- powering means for actuation of the Peltier-effect unit, the housing means being arranged to accommodate the switch means and the electrical-powering means whereby the device is a self-contained portable heat control device. The device enables heat transfer to be made from or to the body for comfort or refreshment purposes, and in this respect the device may be adapted to be worn on the body, for example in the nature of a wπst- or head-band, with the heating surface or the cooling surface held, for example, against the inside of the wrist or agamst the forehead, where blood vessels are close to the skin surface. In this way rapid and effective transfer of heat for cooling or warming the body can be achieved. More particularly, the cooling or warming can be achieved with economical expenditure of electrical energy and under close control. In the latter respect, the electrical-powering means may involve one or more batteries, for example re-chargeable lithium ion batteries or primary thin cell batteries, one or more solar panels, or an electrical generator (for example driven by a clockwork motor, or by kinetic energy using a motion-sensitive mechanism) that is carried by the housing means for providing current to energise the Peltier-effect unit. Conveniently the Peltier-effect unit, the switch means and the electrical-powering means are accommodated in a single housing, although the electrical-powering means and may be the switch means could be disposed in a separate housing to that of the Peltier effect unit. The switch means may be, for example, a toggle or other mechanical switch that is operated manually for on-off control of current flow, but may involve an electronic timing or pulsing circuit to regulate the flow. Personal heat-control devices in accordance with the present invention, will now be described. by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a device according to the invention in side elevation; Figures 2 and 3 are plan views of the device of Figure 1 from opposite sides, with an attachment strap of the device broken away; Figure 4 shows an illustrative sectional view of a preferred embodiment of a personal heat-control device for use as a headband, viewed from the right and above; Figure 5 shows a cross-section through the housing of the device illustrated in Figure 4; Figure 6 is an enlarged cross-section ofthe centre ofthe housing shown in Figure 5; and Figure 7 is an illustration of an alternative configuration ofthe preferred embodiment and to be used as a wrist band. Referring to Figures 1 to 3, a heat-control device, for use in cooling the body and adapted to be worn on the wrist, includes a Peltier-effect or thermoelectric-cooling unit 1 having ceramic heat- conductive cooling and heating surfaces, 2 and 3 respectively, on opposite sides. The unit 1 is set within a stainless-steel or other elongate housing 4 that is carried by a leather, metal or fabric strap 5 for attaching the device around the wrist. The strap 5 includes in the latter respect a buckle 6 for fastening the housmg 4 tightly to the wrist with the surface 2 inside and located agamst the skin on the inside of the wrist. The housinc 4 is bowed outwardlv sliεhtlv so as to conform to the wrist and ensure good heat conduction between the surface 2 and the blood vessels just beneath the skin. Two compartments 7 and 8 for electric primary-cell or rechargeable batteries (not shown) are provided on the inside of the housing 4, the batteries being connected within the housing 4 to energise the Peltier-effect unit 1 via a toggle on-off switch 9 that is mounted on the outside of the housing 4. Energisation of the unit 1 causes heat to be absorbed by the inside suiface 2 and given off by the outside surfece 3. The heat absorbed by the surface 2 in contact with the inside of the wrist cools the body, and the heat given out by the surface 3 is dissipated into the atmosphere. The wearer ofthe device operates the switch 9 to energise the unit 1 for a short while whenever the benefit of personal cooling is required. The period of time for which it remains energised may be at his/her choice, but such choice will normally take account of the desirability to conserve battery-power. A digital indicator 10, mounted on the outside of the housing 4, gives an indication of battery performance/life to assist in this regard. Although the device of Figures 1 to 3 has been described above as including the strap 5 fastened by a buckle, other means of fastening may be use; for example, a partial-release tensioner as used with metal watch straps may be used. or. especially where the strap is fabric, the fastening may be by means of fabπc hook-and-loop engagement such as involved in fastenmirs sold under the Registered Trade Mark VELCRO. Alternatively, the strap 5 may simply be an elastic loop. Moreover, a watch (or other item of personal wear) may be incorporated in the device, this being located, for example, in place of the buckle 6 as illustrated in Figure 1. The device described with reference to Figures 1 to 3 may be worn as an anklet, or when provided with a larger strap, elsewhere on the leg, or may be worn on the foot (perhaps within a shoe). Furthermore, when provided, for example, with an elastic strap that incoφorates towelling, it may be worn as a head-band as described below. The degree of bowing ofthe housing ofthe device is arranged to conform to, or may be made to be adaptable to, what is appropriate for the location on the body where the device is to be worn. Referring to Figures 4 to 6, in a preferred embodiment of the device the thermoelectric-cooling unit 1 is disposed within a central opening in a metal, e.g. aluminium or stainless steel, lower casing 10 of the subarcuate elongate housing 4, and the underside of the unit 1 lies flush with the inside surface 2 of the housing. The lower casing has side walls bordering an outwardly open channel or trough for receipt of a good heat conductive material, e.g. aluminium or copper, upper casing member 1 1 having a circumjacent layer of insulating material to thermally isolate the casings 10.1 1 from each other. The upper casing member 1 1 is affixed flush with the upper surfaces ofthe lower casing side walls, such as by suitable fasteners, e.g. countersunk screws. (Alternatively, the lower casing member may be fitted within a side wall carried by the upper casing member.) Two lithium-ion rechargeable batteries with solid state electrolyte or lithium thin cell primary batteries 15 are housed on either side of the unit 1 within compartments 7,8 defined by casings 10,11 and the batteries 15 are electrically connected, e.g. by wires or conductive strips, to energise the unit 1 on activation by the wearer of the device of a solid state electronic timing switch 9 mounted on the outside ofthe casing 11. It has been found that a pleasant cooling effect is achieved when the unit is energised for not more than 1 minute, e.g. about 30 seconds or less, and preferably around 15 seconds. Reactivation of the unit may be prevented for a short period, not less than the energisation time, immediately after the operation of the device, by the timing switch circuitry to allow heat generated in the unit to disperse through the outer casing 1 1, which serves as a heat sink. The surface area ofthe heat sink may be several times the size ofthe cooling surface, e.g. five times larger, to promote rapid heat dissipation. The cooling unit 1 is fixed within the housing 4 and to the inside of the upper casing 1 1 by suitable adhesive 12. Adjacent the cooling unit on the inside surface 2 of the housing are cooperating fabric hoop-and-loop fasteners, e.g. fasteners sold under the Registered Trade Mark VELCRO. to releasably secure the housing to towelling portions 13 of a strap 5 for retaining the housing on the wearers ' temple, the towelling portions 13 being joined at their bases by an elastic stπp 14. Of course, an appropriately scaled down version ofthe device depicted in Figures 4 to 6 could be fitted onto a persons ' wrist or ankle. Figure 7 shows an alternative configuration of the preferred embodiment of the device having a generally C-shaped or semi¬ circular housing shaped to fit the wrist and containing a single lithium- ion rechargeable battery with solid state electrolyte or a lithium thin cell primary battery. The timing switch 9 and unit 1 are situated at opposed ends and on opposite sides of the housing with the device located to the side ofthe wrist and the switch 9 preferably disposed upwardly ofthe wrist to facilitate its activation. The device is shown in Figure 7 with a strap 5 made from stainless steel with a clasp or buckle to hold it firmly in place on the wearer ' s wrist, but it could equally be provided with a towelling and/or elastic strap as previously described. A highly thermally conductive strip or sheet of material, e.g. aluminium or stainless steel foil, can be spring mounted adjacent the cooling surface 2 to press against the skin and thereby ensure a good contact is achieved between the skin of the wearer and the unit. Additionally the sheet of material may have a larger surface area than the cooling surface of the unit to increase the cooling area ofthe unit. The cooling effect of the device has been found to be most effective when the unit is positioned adjacent the blood vessels in the middle ofthe underside ofthe wearer ' s wrist or at the temple, as these blood vessels are close to the skin in this region and the blood cooled by the unit 1 is carried to other parts of the wearer ' s body. By concentratmg the coo ng effect ofthe device in this region ofthe wπst the size ofthe umt 1 can be minimised without reducing its efficiency, and the number of times the batteπes 15 can be energised before they require recharging or replacement can be maximised. The utilisation of hthium-ion batteries with sohd state electrolyte is advantageous as the batteπes weigh less than known rechargeable batteries, e.g. nickel-cadmium batteries, of comparable power output and the batteπes 15 can be moulded to fit within the arcuate housmg. Equally advantageously, lithium thin cell pnmary batteries could be used. As well as being of advantage for comfort and refreshment during general, everyday activities, the device may find specific applications in the medical, surgical and sports contexts. It will be appreciated that the device may be used to provide warming ofthe body by reversing the mounting ofthe umt 1 within the housmg 4 so that the surface 3 contacts the skm. Alternatively, current flow to the unit may be reversed to achieve the same effect. Whether the device is used for heatmg or coolmg, it is important to ensure that the temperature of the surface in contact with the skm remains withm reasonable limits to avoid the possibility of injury to the wearer.

Claims: CLAIMS: 1. A personal heat control device for a person's body, comprising a cooling surface and a heating surface thermally insulated from the cooling suiface, a Peltier-effect unit for cooling the cooling surface and heating the heating surface, the Peltier-effect unit being accommodated in or on housing means connected to attachment means for attachment ofthe device to a part ofthe person's body with one of said surfaces in contact with the skin at said body part, and switch means for selective connection of the Peltier-effect unit to electrical-powering means for actuation ofthe Peltier-effect unit, the housing means being arranged to accommodate the switch means and the electrical- powering means whereby the device is a self-contained portable heat control device. 2. A personal heat control device according to claim 1, wherein the Peltier-effect unit, the switch means and the electrical-powering means are accommodated in a single housing. 3. A personal heat control device according to claim 1 or 2, wherein the switch means comprises a timing switch to energise the unit for a set period of time when actuated. 4. A personal heat control device according to claim 3, wherein the timing switch energises the unit for not more than one minute. 5. A personal heat control device according to claim 3 or 4 wherein the timing switch prevents the reactivation of the unit for a period of time not less than the energisation time. 6. A personal heat control device according to any one of the preceding claims, wherein the electrical powering means comprises one or more batteries. 7. A personal heat control device according to claim 6, wherein the or each battery is a lithium-ion rechargeable battery or a lithium thin cell primary battery. 8. A personal heat control device according to any one of claims 1 to 4, wherein the electrical powering means comprise one or more solar panels. 9. A personal heat control device according to any one of the preceding claims wherein the cooling surface is arranged for contact with the body part. 10. A personal heat control device according to claim 9, wherein the cooling surface is defined bv a laver of highly thermallv conductive material disposed interjacent the Peltier-effect unit and the body part when the device is worn. 11. A personal heat control device according to any one of the preceding claims, wherein the housing is substantially rigid and arcuate to conform to the body part to which the device is fitted. 12. A personal heat control device according to any one of the preceding claims wherein the attachment means comprises a strap which is elastic or can be tightened to hold the cooling surface in close contact with the skin of the body part.

Inventors: ARNOLD ANTHONY PETER, ARNOLD, ANTHONY, PETER
Applicants: ARNOLD ANTHONY PETER, KOOL LIMITED, ARNOLD, ANTHONY, PETER
Application year: 1996
Main classification: A61F7
IPC codes: A61B17, A61F7