Shoe With Internal Foot Warmer

1. The Field of the Invention

This invention relates to electrically heated clothing and, in particular, to a shoe with an internal warming mechanism.

2. Brief Statement of the Prior Art

Electrically heated clothing such as gloves, mittens, etc., have been suggested by prior investigators. Usually, these suggestions have contemplated using a battery pack as the electrical power source which is connected through thermostats and/or switches to an electric resistance heating coil located in a glove or mitten.

These suggestions in the prior art have not been successfully commercialized since the electrical power requirements for the applications are substantial, exceeding that which can be supplied from a battery pack of acceptable size and portability. Additionally, batteries are very inefficient at low temperatures.

Although the feet and toes are the most sensitive to chilling and frostbite, these applications are not readily adaptable for warming of feet since the battery packs required are too cumbersome to be carried on the feet or lower limbs of the wearer with the result that lengthy power supply conductors must be used between the battery pack and the electrical resistance wiring.

The bulk, and low efficiency of batteries in cold weather are significant detractants to the use of electrically heated clothing in active outdoor activities such as skiing, skating, hiking, etc.

This invention is a shoe with an internal warming mechanism. The warming mechanism includes an electrical resistance wiring or coil for converting electrical energy to thermal energy and this wiring is preferably encased in the subassembly of the sole and upper portion of the shoe.

The source of electrical energy for the mechanism includes an electrical power generator which is coupled to a mechanical transducer to convert movements of the wearer's foot into electrical energy. To this end, the heel of the shoe has a hollow cavity in which are positioned: an electrical generator, and lever means for translating the vertical movements of the wearer's heel into a mechanical force that drives the armature of the electrical generator. In a specific embodiment, the electric generator comprises an armature that is mounted for rotary movement within a magnetic field stator. The armature is mechanically coupled to a flywheel that is rotatably mounted in the heel cavity. The sole of the shoe has an internal heel plate which is coupled, on its undersurface, to a post that is received in a cylindrical sleeve. The cylindrical sleeve is rotatably mounted in the cavity of the heel and coupled by an escapement to the flywheel to translate up-and-down movements of the post to unidirectional rotary movement. The flywheel has peripheral gear teeth which engage driven gears on the input shafts of the armatures.

The invention provides significant advantages over the prior art. The electrical power required for the resistance wiring in the shoe is developed from electrical generation means carried within the heel of the shoe, thus eliminating lengthy wiring conductors and bulky and cumbersome battery packs. Since the electrical heating mechanism is entirely self-contained within the shoe, its use and application is simple and direct without requiring installation or attachment of external wires and the like. Instead, the user simply puts the shoe on, switches the warming mechanism and then performs normal activities, such as skiing.

The invention will be described with reference to the figures of which:

FIG. 1 is an elevational view, partially in cross section, of the shoe of the invention;

FIG. 2 is a view along line 2--2' of FIG. 1;

FIG. 3 is a view along line 3--3' of FIG. 1;

FIG. 4 is a view along line 4--4' of FIGS. 2 and 6;

FIG. 5 is a view along line 5--5' of FIG. 2;

FIG. 6 is a view along line 6--6' of FIG. 4;

FIG. 7 is a view along line 7--7' of FIG. 6;

FIG. 8 is a view along line 8--8' of FIG. 4;

FIG. 9 is a view along line 9--9' of FIG. 4;

FIG. 10 is an exploded perspective view of the working elements of the invention;

FIG. 11 is an elevational sectional view of another embodiment of the invention;

FIG. 12 is a view along line 12--12' of FIG. 11; and

FIG. 13 is a view along line 13--13' of FIG. 11.

The invention will be described with reference to FIG. 1, which illustrates the shoe of the invention in partial cross section. Externally, the shoe of the invention appears to be insignificantly different than a conventional shoe. The shoe 10 has a conventional sole 12, which is formed in a subassembly with an upper portion 13, with conventional assembly techniques, e.g., sewing, gluing, etc. The upper portion 13 includes a toe cover 14, side panels such as 16 and, preferably, an anklet portion 18, all of which are laced together with conventional lacing 20. The specific application illustrated is with reference to a ski boot, however the invention is equally applicable to any other foot apparel. Internally, the shoe has a sole plate 22 which is pivotally mounted in the toe by hinge 25 having a spring clip 27 (see FIG. 10) which serves as a hinge pin. At the heel end, sole plate 22 has a pin 21 which is received in a short vertical, centrally located channel 23, which limits lateral movement and serves as a vertical limit for travel of the pin 21.

As shown in FIG. 2 the sole plate 22 of shoe 10 also has a conventional appearance, with a smooth cloth or leather cover lining the inside bottom of the shoe. The sole plate 22 extends over the heel. As shown in FIGS. 1 and 2, the heel 32 has a front cavity 33 and a central cavity 34. Cavity 34 receives a sealed housing 37 (not shown in cross-section) in which is mounted the electrical generation mechanism of the invention.

Referring now to FIG. 3, the sole plate 22 has, encased within it and beneath its outer cover, an electrical resistance heater 24 formed of serpentine windings of a small diameter electrical conductor 30. The various portions of the upper of the shoe 10 could, besides, or alternatively, contain such electrical resistance element. Electrical conductors 31 and 35 extend from heel 32, along sole 12 from the electrical generation cavity 34 to the terminals of heater 24.

As shown in FIG. 4, which is an elevational cross sectional view along line 4--4' of FIGS. 2 and 6, the heel 32 has an interior cavity 34 which receives an enclosed housing 37 which contains the electrical power generator means. The cavity 34 lies beneath the heel portion of sole plate 22. As shown in FIG. 5, sole plate 22 has a slot 41 and supports, on its under surface, a longitudinal rib 44. The longitudinal rib 44 is received in an arcuate recess on the upper end of post 48 and this post is coupled to the bar by a suitable spring clip 50 which is received in bore 45 of post 48, thereby permitting rocking of the sole plate 22 on post 48.

The post 48 is received in sleeve 52 that is rotatably mounted in an interior cylindrical recess 51 of the housing 37. To this end, an annular bearing 54 (either a roller or ball bearing) is provided near the upper end of sleeve and the lower end of the sleeve has a arcuately rounded bearing end 56 which is received against the bottom surface 58 of the housing 37 which is received in the heel cavity 34. The post 48 is retained in recess 51 by spring clip 53 (see FIG. 10) which expands into annular chamber 55 of housing 37.

The housing 37 also rotatably receives flywheel 60 which is mounted on the upper end of the sleeve 52. The flywheel 60 has a central aperture 62 (see FIG. 6) which receives a radial cam ring 64 which is fixedly secured to the upper end of the sleeve 52. As shown in FIG. 6, the cam ring 64 has a plurality of inset notches 66 which serve as receptacles in which are mounted a like plurality of cam rollers 68. The radial cam ring 64 and its assembly in the flywheel 60 as thus described provides an escape mechanism for the translation of rotary movement shown by the double arrowhead line from sleeve 52 to the flywheel 60. In the illustrated embodiment, clockwise rotation of the sleve 52 will not be translated to the surrounding flywheel 60 as the rollers 68 simply rotate in their receptacles, notches 66. Counter clockwise rotation of the cam ring 64, however, will move the inclined cam surfaces of notches 66 toward the rollers 68, wedging the rollers 68 firmly between the cam ring 64 and the surrounding flywheel 60, causing movement of the flywheel (in the direction shown by the single arrowhead line) with movement of the sleeve.

Up-and-down, reciprocal movement of the post 48 is translated to rotary movement of the sleeve by the helical groove 47 which is milled in the interior wall of the sleeve and which receives a pin 57 that is fixedly secured in the post 48. If desired, suitable bearings (not shown) can be placed on pin 57.

The post 48 is driven downwardly by the downward movement of the heel of the wearer, which is transferred through the sole plate 22, rotating sleeve 52 and its interlocked flywheel 60. Upward movement of the post and sole plate, however, reverses the rotation of the sleeve 52 but does not effect relative rotation of the flywheel 60.

Positive lift means for the internal sole plate 22 is provided by the resilient torsion spring subassembly located in heel cavity 33. The spring subassembly includes a pair of torsion coils 72 and 74, of a resilient spring wire and having dependent arms 78, 80 and 82 extending from opposite ends of each coil. Arm 78 rests against the bottom plate 35 in the cavity 33 within the heel which receives the resilient spring subassembly. The upper arms 80 and 82 of the spring subassembly are received in slots 84 of brackets 86 that are fixedly secured to the under surface of the interior sole plate 22. In this fashion, the sole plate 22 can move downwardly under applied pressure from the weight of the wearer, tensioning the torsion springs so that when the wearer's weight is released, the torsion springs lift the sole plate upwardly, restoring it for the succeeding downward flexing under the weight of the wearer. Although the resilient torsion springs could be mounted in cavity 34 of the heel, which receives the electrical generation mechanism, it is preferred to locate this spring subassembly 70 in a forwardly located, second interior cavity 33.

The mechanism is provided with suitable lock means to disengage the electrical generation mechanism. This comprises latch pins 92 and 94 which are located in the forward heel cavity 33 and which project through the forward face 96 of the heel. A small wheel or button 91 is fixedly mounted on each pin 92 and 94. Although not shown, a suitable seal such as an O-ring, surrounds each pin, sealing it in the forward face 96 of the heel. The latch pins include dependent prongs 93 and 95 which can be seated in latch pin apertures 97 and 99, in brackets 86 and 87, respectively when the heel plate is depressed. Brackets 87 are secured to the bottom plate 35 so that the entire mechanism can be locked together with the spring subassembly 70 in its compressed condition. The latch pins 92 and 94 each have tension springs 89 to biase the pins outwardly from cavity 33.

The embodiment shown in FIGS. 11-13 increases the rotational speed of the armatures in response to up-and-down movements of the wearer's heel over that obtained in the embodiment of FIGS. 1-10. High gear ratios from 15 to about 250, preferably from about 20 to 150, can be used as there is ample force or rotational torque which is applied to the flywheel 60 by post 48 which is responsive to the weight of the wearer. These high gear ratios provide very favorable multiplication of the rotational speed of the armatures, e.g., for every rotation of flywheel 60, the spur gears 112 rotate from 15 to 250, preferably 20 to 150 times, as determined by the gear ratio in the drive train.

The invention includes suitable electrical conductors, generally shown as wires 31 and 35 which extend from each of the terminals of the electrical generators to the electrical resistance heater 24 shown in FIG. 3. These conductors place the electrical generators 102 and 104 in series connection with the electrical resistance heating element 24.

If desired, a suitable connector receptacle 111 (see FIGURE 1) can be positioned along the top edge of the upper of the boot and can be connected in circuit with the electrical generation mechanism of the invention. This permits the user to connect with a simple two-pronged connector and cable for tapping of electrical power which can be directed to other wearing apparel, e.g., electrically heated gloves, mittens, jacket, earmuffs and the like.

The bottom of housing 37 is shown in FIG. 8 with a trapezoidal shape. The entire housing can be sealed with a cover plate 39 (see FIG. 4) which has a single aperture that receives post 48. A seal ring 49 is placed about post 48 to maintain the interior of housing 37 sealed against dirt and moisture.. The housing can be reinforced with a stiffening rib 43 which extends along its rear wall, externally of the housing; see also FIG. 9.

As previously mentioned, the invention includes suitable electrical generators. The illustrated embodiment has two small electrical generators 102 and 104, each located in opposite, forward corners of the interior cavity 34 of the heel. Each of the electrical generators 102 and 104 includes a permanent magnet 108 and a rotatably mounted armature 110 having an internal coil. The armature is rotatably mounted within the surrounding magnets 108. The armatures 110 have a conventional shaft on which is fixedly secured a spur gear 112. The spur gear of each of the generators is connected to the flywheel by the gear teeth 61 disposed on the periphery of the flywheel 60. Alternatively a belt of sprocket chain linkage could also be used.

Referring now to FIGS. 11-13, another embodiment of the invention is shown in which additional gears are provided in the gear train between the flywheel and the spur gears 112. As shown in FIG. 13, the housing 37' is modified slightly from that shouwn in FIGS. 1-10 to provide a forward compartment 70 which receives a multiplication gear 63 that is mounted on shaft 67 which also supports spur gear 65. The shaft 67 is rotatably received in a bearing (not shown) at its upper end and its lower end resting in a bearing 71 on the bottom 58 of housing 37'. The two electrical generators 102 and 104 are mounted on opposite sides of gear 63 with their spur gears 112 engaged with the peripheral teeth of gear 63. The small spur gear 65 is engaged with the peripheral teeth of gear 60.

The invention provides significant advantage over the prior art. Bulky and cumbersome battery packs are eliminated, together with marginal performance under freezing weather conditions. The very repetitive and forceful weight applications of the wearer on the heel of each shoe is effectively transformed into electrical energy which warms the toes and feet of the wearer. Additionally, the spring resistance and the resistance of the electrical generators provides a resilient, shock-absorbing action, avoiding heel bruises and fatigue to the wearer. The shoes or boots of the invention can be used without any particular instruction or changes in the habits or performance of the wearer. The mechanism does not add significantly to the overall weight of the shoe and, since it is entirely self-contained within the shoe and heel, no compromise in structure is required. Although the electrical generators are relatively small, they are highly effective in generating sufficient electrical power to maintain the toes and feet of the wearer comfortable even in sub-zero climates. This effectiveness increases significantly with increasing physical activity by the wearer.

The invention has been described with reference to the illustrated and presently preferred embodiment. It is not intended that the invention be unduly limited by this disclosure of the presently preferred embodiment. Instead, it is intended that the invention be defined, by the means, and their obvious equivalents, set forth in the following claims: