the principles of the invention will be understood by reference to the examples of embodiments thereof shown in fig1 - 8 . a first embodiment of the invention , shown in fig1 - 3 , takes the form of a device 10 comprising a main body 12 of flexible fabric material having a length ( left to right horizontal extent in fig3 ) and width ( top to bottom vertical extent in fig3 ), and a pocket 14 into which a heat transfer element 15 ( fig4 ) can be received in lengthwise central location relative thereto . the pocket 14 is dimensioned , configured and adapted so that the received element 15 will extend sufficiently lengthwise to circumferentially envelop the back and sides of the neck of a user , but leave left and right free ends 16 , 17 of sufficient length to permit loose tying of the main body at the free ends in front of the neck , as illustrated in fig1 . the main body 12 , in the embodiment shown in fig1 - 3 , comprises a generally rectangular strip of material having a length generally six times greater than its width . the material is hemmed along upper and lower longitudinal edges 18 , 19 and left and right lateral edges 20 , 21 by folding border portions thereof over toward the front face of the portion 12 and sewing them down along stitch lines 23 . the pocket 14 is formed by applying a second generally rectangular piece 24 of the same material onto the front face of the material 12 , aligned centrally along the lower edge 19 . the pocket 14 is formed by joining the piece 24 to the main body 12 along border stitching lines 26 . for the shown embodiment , the piece 24 ( and , thus , the resulting pocket 14 ) has a length just under one - half the length of the main body 12 , and a width about two - fifths to one - third the width of the portion 12 . suitable dimensions for the main body 12 and pocket 14 are 32 &# 34 ;× 6 &# 34 ; and 15 &# 34 ;× 2 &# 34 ;, respectively . an opening 27 , provided in or along the edge of the material 24 to give access to the interior of the pocket 14 , is fitted with a conventional releasible closure mechanism , such as the zipper 28 shown . the pocket 14 and opening 27 are dimensioned , configured and adapted to accommodate the receipt of a heat transfer element 15 . the element 15 may take the form of a multi - cellular segmented pouch 29 , as shown in fig4 . the pouch 29 comprises a series of joined plastic film cells 30 filled with a known heat exchange substance , such as a repeatably refrigerable conventional coolant compound 31 . the pouch 29 is configured to substantially match the length and width of the pocket 14 , so that placement of the heat transfer element 15 will be determined by placement of the pocket 14 . the pouch 29 could also be constituted by a single elongate member or a plurality of separate cells . similarly , single - use chemical reactants could be employed in place of the reusable formulation 31 . with the device 10 utilized as a cooling neckband , the pouch 29 ( fig4 ) is placed within the pocket 14 after refrigeration , and the opening 27 closed ( fig3 ). the main body fabric 12 is then folded widthwise in half along its length ( fig2 ), bringing the upper edge 18 over and across the material 24 ( as viewed in fig3 ), and placed with the pouch 29 circumferentially positioned about the neck back and sides . the folded device 10 can be located with one layer of fabric material between element 15 and the neck , as shown in fig2 to bring the left free end 16 proximate the left shoulder and the right free end 17 proximate the right shoulder . alternatively , the device 10 may be reversed ( not shown ) to have two layers of material ( one layer of piece 24 and one layer of piece 12 ) intermediate the element 15 and the neck , with the left free end 16 proximate the right shoulder and the right free end 17 proximate the left shoulder . in either orientation , the unobstructed free ends 16 , 17 may be tied together in front of the neck , as shown in fig1 . the stylishness of the device 10 can be enhanced by choosing bold colors and decorative prints for the fabric making up the main body 12 and pocket 14 . choice of a rayon or similar synthetic woven or knitted material provides a readily washable , comfortable device . the heat transfer element 15 can be permanently embedded in the main body 12 , if desired ; however , making element 15 removable for cooling or heating apart from the remainder of the device , if reusable , reduces wear and tear on the device . fig5 shows a modified embodiment of device 10 in the form of a device 110 having a length bounded by left and right pointed corners 120 , 121 , and a width bounded by an upper longitudinal edge 118 and a central apex 119 of an inverted triangular portion of a main body 112 . a pocket 114 is formed by applying border stitching 126 along three edges of a rectangular piece of material 124 . a left edge is left unstitched to form an opening 127 within which complementary parts of a velcro ™ hook - and - eye fastener are arranged to provide a releasible closure . the length of the pocket 114 and main body 112 of device 110 have the same relative dimensions as the corresponding lengths of the pocket 14 and main body 12 of device 10 , discussed above . the width of the main body 112 is , however , much greater relative to the width of pocket 114 , than the width of the main body 12 is to pocket 14 . the scarf - like configuration of device 110 enables the inverted triangular portion to be repeatedly overlapped about the pocket 114 , if desired , to adjust the number of layers of material to be located between the heat transfer element 15 and the neck . ( the position of the first overlap is suggested by the dot - dashed lines in fig5 with the point 119 being brought up and over the pocket 114 to a position 119 &# 39 ;.) left and right free ends 116 , 117 , not obstructed by the coolant - filled pocket 114 , can be tied at the front of the neck as with the corresponding free ends 16 , 17 of device 10 . fig6 shows another embodiment 10 &# 39 ; of the device 10 , wherein the width of the pocket 14 &# 39 ; is generally coincident with the width of the body 12 &# 39 ;, but the lengths of the free ends 16 &# 39 ;, 17 &# 39 ; have been extended . the edges 18 &# 39 ;, 19 &# 39 ;, 20 &# 39 ; and 21 &# 39 ; are depicted as straight ; however , it will be appreciated that the lengths of the ends 16 &# 39 ;, 17 &# 39 ; can be sufficiently extended and the edges 18 &# 39 ;, 19 &# 39 ;, 20 &# 39 ; and 21 &# 39 ; appropriately configured , so that the free ends 16 &# 39 ;, 17 &# 39 ; can be tied in a knot having depending front and rear flaps in the manner of a scarf or necktie . the piece 24 &# 39 ; can be constituted by a layer of material having a different thermal conductivity than that of the material of the rest of the body 12 &# 39 ;, so that the degree of heat transferred between the element 15 and the skin can be controlled by selecting which side of the device 10 &# 39 ; is placed facing the neck ( i . e ., piece 24 &# 39 ; side or body 12 &# 39 ; side ). alternatively , the same effect can be achieved by utilizing multiple layers of the same material for either the piece 24 &# 39 ; or the remainder of the main body 12 &# 39 ;. fig7 shows another means of controlling the degree of heat transfer , wherein a difference of thermal conductivity is provided on the heat transfer element , rather than on the pocket itself . an element 15 &# 39 ; includes a pouch 29 &# 39 ; having one or more plastic film cells 30 &# 39 ; filled with coolant compound 31 . the cells 30 &# 39 ; differ from the previously described cells 30 in that one side of the pouch 29 &# 39 ; is covered with an insulating material 32 which has a lower thermal conductivity than the film material 33 of the other side . the degree of heat transfer between the device 10 &# 39 ; and the skin can , thus , be chosen by selecting which side of the pouch 29 &# 39 ;, received within the pocket 14 &# 39 ;, will face the neck . this provides heat transfer control without the need for varying the types of material or number of layers that comprise the respective sides of the pocket 14 &# 39 ;. fig8 shows a variation 10 &# 34 ; of the device 10 of fig2 wherein complementary parts 41 , 42 of a velcro ™ hook - and - eye fastener are arranged respectively on the free ends 16 , 17 , to provide means for joining the free ends 16 , 17 , without tying . this fastening arrangement enables the device 10 &# 34 ; to provide a loosely wrapped , sporty look , without the risk that the device 10 &# 34 ; will fall off . those skilled in the art to which the invention relates will appreciate that the preferred embodiments of the invention described in detail above are just examples of how the invention can be implemented , and that various substitutions and modifications can be made to the same without departing from the spirit and scope of the invention as described by the claims below .
a heat transfer device in the form of a bandanna - like neckband has a main body of flexible fabric material and a pocket lengthwise centrally located for receiving an elongated heat transfer element in the form of a multi - cellular reusable coolant pouch therein . the lengths of the main body and pocket are chosen to place the heat transfer element about the back and sides of the neck , while leaving the main body unobstructed at free ends to permit loose tying to join the ends in front of the neck . the widths of the main body and pocket are chosen to enable single or multiple layers of fabric material to be optionally interposed between the heat transfer element and the neck .