Patent Publication Number: US-2019191812-A1

Title: Hat with forced air cooling

Description:
FIELD 
     This disclosure relates generally to a head covering and, more particularly, a head covering with forced air cooling. 
     BACKGROUND 
     Hats with fans have been used to help cool people in hot climates. Such hats can benefit construction workers who often work outdoors. Construction work often requires long hours at a job site, so a high capacity battery could be used to allow cooling for an extended period of time, or multiple replacement batteries could be used throughout the day. However, high capacity batteries can be heavy, and replacement batteries can be cumbersome and inconvenient. Another issue is that cooling effectiveness is greatly reduced when ambient air temperature is extremely high. Although blowing air over the skin can have a cooling effect due to evaporation of sweat, continuously blowing air that is much greater than body temperature can have an overall effect of making the person warmer. Accordingly, what is needed is a system that addresses power management and/or cooling effectiveness in hot climates. 
     SUMMARY 
     Briefly and in general terms, the present invention is directed to a hat and method for cooling. 
     In aspects of the invention, a hat comprises a shell, a liner, a PCM container, and a fan. The shell comprises a concave interior surface. The liner is attached to the shell, the liner comprising a convex upper surface, there being an air passage formed by a gap between the convex upper surface of the liner and the concave interior surface of the shell. The PCM container contains a phase change material. The fan is arranged to draw air over portions of the PCM container to cool the air and force the cooled air into the air passage. 
     In aspects of the invention, a method for cooling uses a hat comprising a shell, a liner attached to the shell, a PCM container attached to the shell and containing a phase change material, and a fan attached to the shell. The method comprises activating the fan to draw air over portions of the PCM container to cool the air and force the cooled air into an air passage formed by a gap between a concave interior surface of the shell and a convex upper surface of the liner. 
     The features and advantages of the invention will be more readily understood from the following detailed description which should be read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded schematic view of an example hat having a shell and a liner. 
         FIG. 2  is an assembled schematic view of the hat. 
         FIG. 3  is a bottom-front perspective view of an example shell. 
         FIG. 4  is a top-rear perspective view of an example liner. 
         FIG. 5  is a top view of the liner. 
         FIG. 6  is a cross-section view of the liner taken along line  6 - 6  in  FIG. 5 . 
         FIG. 7  is a top-front perspective view of an example hat. 
         FIG. 8  is a schematic block diagram showing example electrical components of the hat. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now in more detail to the example drawings for purposes of illustrating aspects of the invention, wherein like reference numerals designate corresponding or like elements among the several views, there is shown in  FIGS. 1 and 2  an example hat  10  that comprises shell  12 , liner  14 , PCM container  16 , and fan  18 . 
     Shell  12  is in the shape of a hard hat suitable for use at construction sites. For example, shell  12  can be made of acrylonitrile butadiene styrene (ABS) material, other thermoplastic polymer, or other polymer plastic. Shell  12  can have a wall thickness in the range of 2 mm to 4 mm. The shell can have other shapes. 
     Air intake hole  20  is formed through shell  12 . Fan  18  is arranged to draw air through air intake hole  20  and into shell  12 . Shell  12  comprises concave interior surface  22 , and liner  14  is attached to concave interior surface  22  by securement  24 . Securement  24  is configured to secure liner  14  to shell  12  and to release liner  14  from shell  12 . Securement  24  can be a post on concave interior surface  22  of shell  12 . The post may be threaded or ribbed. The post may engage hole  26  formed into liner  14  to secure liner  14  to shell  12 . Engagement may be achieved by friction between the post and hole  26 , wherein the friction is at a level that allows for release of liner  14  from shell  12 . For example, a user may pull liner  14  apart from the shell  12  to overcome the frictional engagement between liner  14  and shell  12 . Removal of liner  14  can allow for cleaning and maintenance of hat  10 . Other types of securement can be implemented. For example, securement  24  can be a hook or latch. As a further example, securement  24  may be in the form of hook and loop tape, such as Velcro®. 
     Liner  14  comprises convex upper surface  28 . When liner  14  is secured to shell  12 , air passage  30  ( FIG. 2 ) is formed by a gap between convex upper surface  28  of liner  14  and concave interior surface  22  of shell  12 . 
     PCM is an acronym for phase change material. PCM container  16  contains phase change material  34 . Fan  18  comprises an electric motor and fan blades attached to the motor. Fan  18  is arranged to draw air over portions of the PCM container to cool the air and force the cooled air into air passage  30 . For example, fan  18  can be mounted inside shell  12  as illustrated. As a further example, fan  18  can be mounted outside of shell  12 . 
     Phase change material  34  absorbs energy when it undergoes a phase change, such as a solid/liquid phase transition or a solid/solid phase transition. The temperature of a phase change material can rise when it absorbs heat, but when the phase change material reaches its phase change temperature (e.g., melting temperature), the phase change material continues to absorb heat while its temperature remains almost constant at the phase change temperature. PCM container  16  should contain a phase change material having a phase change temperature below normal human body temperature of 37° C. (98° F.). For example, without limitation, phase change material  34  can be paraffin wax having a phase change temperature in the range of 24° C. to 32° C. Tests performed by Applicant using this material in a hat with forced air flow showed that skin temperature of the wearer was reduced by as much as 10° C. (18° F.). Other phase change materials known in the art can be used. 
     PCM container  16  can effectively enlarge the ambient air temperature range at which hat  10  can provide effective cooling. As previously mentioned, using forced air at temperatures that are much greater than body temperature can have an overall effect of making the person warmer. PCM container  16  can allow a cooling effect to be achieved even in extremely hot climates by reducing the temperature of the forced air to a temperature below body temperature. 
     PCM container  16  is configured to be removed from shell  12  without damage to PCM container  16  and shell  12 . Removability of PCM container  16  allows it to be reconditioned in a refrigeration unit, such as a freezer, without shell  12 . This saves space in the refrigeration unit and allows many PCM containers to be reconditioned together. 
     For example, PCM container  16  can be configured to slide on and off of shell  12  by means of posts  32  ( FIG. 1 ), as illustrated, or by means of a pocket located on or within shell  12 . Post  32  may be threaded or ribbed. Each post  32  may engage holes formed in PCM container  16 . Engagement may be achieved by friction between posts  32  and PCM container  16 , wherein the friction is at a level that allows for release of PCM container  16  from shell  12 . For example, user may pull PCM container  16  apart from the shell  12  to overcome the frictional engagement between PCM container  16  and shell  12 . Other types of securement can be implemented. For example, the posts can be hooks or latches. As a further example, posts  32  may be configured to engage screws that retain between PCM container  16 . 
     As shown in  FIG. 3 , shell  12  comprises outer edge  36 . Outer edge  36  forms the bottom of hat  10 . Outer edge  36  comprises front edge  38 , left edge  40 , right edge  42 , and rear edge  44 . From the perspective of the wearer, left edge  40  extends leftward from front edge  38 . Right edge  42  extends rightward from front edge  38 . Rear edge  44  is located opposite front edge  38  and extends from left edge  40  to right edge  42 . Outer edge  36  defines head opening  37  sized to accept a person&#39;s head such that the person&#39;s face is disposed below front edge  38 . 
     As shown in  FIGS. 4 and 5 , grooves  46  are formed into convex upper surface  28  of liner  14 . Each grooves  46  extends linearly, as shown in  FIG. 5 , from rear edge  44  ( FIG. 3 ) of shell  12  to front edge  38  of shell  12 . Five grooves are illustrated, although a lesser or greater number of grooves may be implemented. For example, only a single groove could be formed in the liner. 
     Grooves  46  define, at least in part, air passage  30  ( FIG. 2 ). Air passage  30  may be located exclusively in grooves  46 . Alternatively, air passage  30  may be located in grooves  46  and above other areas of convex upper surface  28  of liner  14 . 
     Grooves  46  help to direct cooled air from the rear of hat  10  to the front. Each groove  46  forms exhaust vent  48  ( FIG. 2 ) at forward end  50  ( FIG. 5 ) of groove  46 . Exhaust vent  48  ( FIG. 2 ) directs the cooled air toward front edge  38  ( FIG. 3 ) of shell  12  to cool the person&#39;s face. 
     As shown in  FIG. 6 , liner  14  can be double-walled. There is convex upper surface  28  with grooves  48  and dome surface  52  below convex upper surface  28 . Dome surface  52  is shaped to support the persons head comfortably. Dome surface  52  is attached to and spaced part from convex upper surface  28  so as to form liner air gap  54  between dome surface  52  and convex upper surface  28 . Dome surface  52  may be attached to convex upper surface  28  by ultrasonic welding, adhesives, molding dome surface  52  and convex upper surface  28  as a unitary structure, or by other means. Liner air gap  54  may be hermetically sealed by dome surface  52  and convex upper surface  28  to prevent entry of dirt, facilitate cleaning of liner  14 , and enhance thermal insulation properties. 
     The double-walled configuration of liner  14  may provide multiple advantages. The double-walled configuration creates distance between the top of the person&#39;s head (which contacts dome surface  52 ) and air passage  30  (which is located above convex upper surface  28 ). The distance and liner air gap  54  insulates the cooled air that travels above convex upper surface  28 , which can help ensure that the air remains cool when it reaches exhaust vents  48  ( FIG. 2 ) of at the forward ends of grooves  46 . In addition, the double-walled configuration can provide the wearer with additional protection by serving as a collapsible structure that can absorb shock in case an object or construction material falls and hits shell  12 . Dome surface  52  and convex upper surface  28  can be made of silicon rubber that has a thickness in the range of 2 mm to 3 mm. 
     Referring again to  FIG. 2 , shell  12  comprises apex  56  and forward-facing quadrant  58 . Apex  56  is the highest part of shell  12 . That is, apex  56  is higher in elevation than all other parts of shell  12 . Forward-facing quadrant  58  extends from front edge  38  ( FIG. 3 ) of shell  12  to apex  56 . Forward-facing quadrant  58  is defined as the region of shell  12  bounded by two vertical planes, which are perpendicular as viewed from above shell  12  and which intersect at the center of shell  12 . The two planes can be imagined as cutting shell  12  into four regions, one of which is forward-facing quadrant  58 . Portions of forward-facing quadrant  58  are located directly above air passage  30 . There is no through-hole formed in any portion of forward-facing quadrant  58  directly above air passage  30 . A through-hole formed in forward-facing quadrant  58  may allow cooled air to escape from air passage  30 . The absence of any such through-hole can increase the amount of cooled air that reaches exhaust vents  48  ( FIG. 2 ) to cool the person&#39;s face. 
     Still referring to  FIG. 2 , shell  12  includes rear-facing quadrant  60  that extends from rear edge  44  ( FIG. 3 ) of shell  12  to apex  56 . Air intake hole  20  is formed through rear -facing quadrant  60 . PCM container  16  is located at rear-facing quadrant  60 . Having PCM container  16  located at the rear of shell  12  allows cooled air to be produced at the rear of shell  12  and then conveyed above the person&#39;s head before the cooled air is discharged from exhaust vents  48  ( FIG. 2 ). Forcing the cooled air circulated over the person&#39;s head could provide the wearer with additional cooling. 
     In addition, having PCM container  16  located on rear-facing quadrant  60  could reduce the possibility that PCM container  16  may obstruct movement of the person&#39;s head in confined working environments. For example, when the person bends to lower his or her head to avoid a low beam, it would be advantageous to have nothing protruding from forward-facing quadrant  58  that might hit the low beam. Having PCM container  16  located on rear-facing quadrant  60  addresses this potential problem and could also allow for placement of a forward-facing lantern or insignia on forward-facing quadrant  58 . 
     As shown in  FIGS. 7 and 8 , hat  10  comprises battery  62  and solar cell  64 . Battery  62  is attached to shell  12 . Solar cell  64  is attached to an exterior surface at apex  56  of shell  12 . Battery  62  is configured to power fan  18 . Solar cell  64  comprises semiconducting materials that exhibit a photovoltaic effect that converts light from the sun to electricity. Solar cell  64  is electrically connected to battery  62  and is configured to charge battery  62 . 
     Use of solar cell  64  allows fan  18  to operate for longer periods of time with a smaller size battery. This can reduce the weight of battery  62  and thus reduce the overall weight of hat  10 . Use of solar cell  64  can also reduce the need to replace a depleted battery while the person is working. 
     Hat  10  comprises power regulator  66  to regulate power from battery  62  to fan  18  and to regulate charging of battery  62  by solar cell  64 . Power regulator  66  comprises electronic temperature controller  68  and temperature sensor  70  coupled to electronic temperature controller  68 . Electronic temperature controller  68  comprises circuits configured to activate and deactivate fan  18  according to signals from temperature sensor  70 . For example, electronic temperature controller  68  may include a microcontroller or microprocessor that receives signals from temperature sensor  70  and determines ambient air temperature based on the received signals. Temperature sensor  70  can be an infrared temperature sensor configured to detect infrared energy which is proportional to ambient temperature. 
     Electronic temperature controller  68  can be programmed to turn on and turn off fan  18  according to the ambient temperature that was determined. Additionally or alternatively, electronic temperature controller  68  can be programmed to adjust the rotation rate of fan  18  (for example, from a first non-zero rotation rate to a second non-zero rotation rate) according to the ambient temperature that was determined. Temperature controller  68  can have memory for storing temperature control parameters. 
     Temperature controller  68  may also take into account the phase change temperature (T) of phase change material  34 . Electronic temperature controller  68  can be programmed to turn on and turn off fan  18  according to the ambient temperature and the phase change temperature (T). Additionally or alternatively, electronic temperature controller  68  can be programmed to adjust the rotation rate of fan  18  according to the ambient temperature and the phase change temperature (T). 
     For example, electronic temperature controller  68  may use a first threshold value stored in its memory. If ambient air temperature rises above the first threshold value, fan  18  will be turned on, and when ambient temperature falls below the first threshold value, fan  18  will be turned off. The first threshold value may be based, at least in part, on the phase change temperature (T) of phase change material  34 . For instance, without limitation, the first threshold value may be equal to the sum of a number (X) and the phase change temperature (T), where X is greater than or equal to 0. This method of power management can conserve battery power by generating forced air only at times when it is needed. Electronic temperature controller  68  may use a second threshold stored in its memory. The second threshold value can be greater than the first threshold value so that when ambient air temperature rises above the second threshold value, the rate of rotation of fan  18  will be increased to allow greater cooling of the air by phase change material  34 . When ambient air temperature falls below the second threshold value, the rate of rotation of fan  18  will be decreased. The availability of a slower rotation can also conserve battery power and it may also allow phase change material  34  to last longer. 
     While several particular forms of the invention have been illustrated and described, it will also be apparent that various modifications can be made without departing from the scope of the invention. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.