Title:
INFLATABLE ARTICLE OF FOOTWEAR
United States Patent 3685176


Abstract:
Footwear comprising an inflatable bladder to be disposed in a boot for embracing a person's foot, ankle and lower leg portion, and having a plurality of intercommunicating flexible tubes adapted to be inflated to a desired pressure, the material and hardness of the bladder and the cross-sections of the inflated tubes being selected to prevent relative lateral movement between the foot, ankle and lower leg portion, while permitting restrained fore and aft movement between such parts. A lower set of tubes bearing against the upper portion of the foot at the ankle joint and a rear set of tubes bearing against the Achilles' tendon region have an inflated cross-section that permits fore and aft movement of the leg with respect to the foot about the ankle joint to effect a decrease in volume of one set, thereby increasing the pressure in the tubes, and producing a corresponding increase in volume and inflation of the other set, to exert a greater downward force holding the bottom of the foot firmly against the heel and sole of the boot.



Inventors:
RUDY MARION F
Application Number:
05/051841
Publication Date:
08/22/1972
Filing Date:
07/02/1970
Assignee:
MARION F. RUDY
ROBERT C. BOGERT
Primary Class:
Other Classes:
36/93
International Classes:
A43B5/04; A43B23/07; (IPC1-7): A63F5/00
Field of Search:
36/2
View Patent Images:
US Patent References:
3410004Pneumatic ski bootNovember 1968Finn
2774152Article of footwearDecember 1956Alber
2638690Article of footwearMay 1953Bullard



Primary Examiner:
Lawson, Patrick D.
Claims:
I claim

1. An article of footwear comprising an inflatable bladder adapted to be disposed within a boot to bear against areas of a wearer's foot, said bladder including a multiplicity of adjacent chamber portions, including a plurality of chamber portions at each side of the foot, said multiplicity of chamber portions communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force on the foot.

2. An article of footwear as defined in claim 1; wherein said chamber portions extend lengthwise of the wearer's foot when disposed thereon.

3. An article of footwear comprising an inflatable bladder adapted to be disposed within a boot to bear against areas of a wearer's foot, said bladder including a plurality of adjacent chamber portions communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force on the foot; said bladder being shaped for disposition of said chamber portions upon the back, sides and top of the foot, whereby said inflated chamber portions substantially restrain the foot against movement relative to the boot.

4. An article of footwear as defined in claim 3; a major number of said chamber portions extending lengthwise of the wearer's foot when disposed thereon.

5. An article of footwear as defined in claim 1; a number of said chamber portions being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating unit pressure.

6. An article of footwear comprising an inflatable bladder adapted to be disposed within a boot to bear against areas of a wearer's foot, said bladder including a plurality of adjacent chamber portions communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force on the foot; a number of said chamber portions being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating unit pressure, other of said chamber portions being of such size and shape as to be deformable after being inflated by the fluid to normal operating unit pressure.

7. An article of footwear as defined in claim 3; said chamber portions disposed at the back of the foot along the Achilles' tendon and at the top of the foot at the ankle joint being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, said chamber portions at the sides of the foot and at the top of the foot forwardly of the ankle joint being substantially rigid after being inflated by the fluid to normal operating unit pressure.

8. An article of footwear as defined in claim 3; a major number of said chamber portions extending lengthwise of the wearer's foot when disposed thereon, said chamber portions disposed at the back of the foot along the Achilles' tendon and at the top of the foot at the ankle joint being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, said chamber portions at the sides of the foot and at the top of the foot forwardly of the ankle joint being substantially rigid after being inflated by the fluid to normal operating unit pressure.

9. An article of footwear as defined in claim 3; a major number of said chamber portions extending lengthwise of the wearer's foot when disposed thereon, said chamber portions at the malleoli of the foot being of toroidal shape.

10. An article of footwear as defined in claim 3; a major number of said chamber portions extending lengthwise of the wearer's foot when disposed thereon, said chamber portions at the malleoli of the foot being of toroidal shape, a chamber portion at the navicular bone of the foot being of toroidal shape.

11. An article of footwear comprising an inflatable bladder to be disposed within a boot and shaped to receive a wearer's foot, said bladder having an upper circumferential manifold tubular portion for embracing the leg above the ankle joint and other tubular portions communicating with and extending downwardly from said manifold portion along the lower end of the leg and along the back, sides and top of the foot, whereby inflation of said tubular portions by a fluid causes said bladder to restrain movement of the leg and foot relative to the boot.

12. An article of footwear as defined in claim 11; said tubular portions above the ankle joint and at the sides of the foot being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating pressure to prevent lateral movement of the leg and foot relative to the boot.

13. An article of footwear as defined in claim 11; said tubular portions above the ankle joint and at the sides of the foot being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating pressure to prevent lateral movement of the leg and foot relative to the boot, said portions disposed at the back of the foot along the Achilles' tendon and at the top of the foot at the ankle joint being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure.

14. An article of footwear as defined in claim 11; said tubular portions above the ankle joint, at the side of the foot, and at the top of the foot forwardly of the ankle joint being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating pressure to prevent lateral movement of the leg and foot relative to the boot.

15. An article of footwear as defined in claim 11; said tubular portions above the ankle joint, at the side of the foot, and at the top of the foot forwardly of the ankle joint being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating pressure to prevent lateral movement of the leg and foot relative to the boot, said tubular portions disposed at the back of the foot along the Achilles' tendon and at the top of the foot at the ankle joint being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, said tubular portions at the lower end of the leg, at the sides of the foot, and at the top of the foot forwardly of the ankle joint being substantially rigid after being inflated by the fluid to normal operating unit pressure.

16. An article of footwear as defined in claim 11; said tubular portions above the ankle joint, at the side of the foot, and at the top of the foot forwardly of the ankle joint being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating pressure to prevent lateral movement of the leg and foot relative to the boot, said tubular portions disposed at the back of the foot along the Achilles' tendon and at the top of the foot at the ankle joint being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, said tubular portions at the lower end of the leg, at the sides of the foot, and at the top of the foot forwardly of the ankle joint being substantially rigid after being inflated by the fluid to normal operating unit pressure, tubular portions at the malleoli of the foot being of toroidal shape.

17. An article of footwear as defined in claim 11; said tubular portions above the ankle joint, at the side of the foot, and at the top of the foot forwardly of the ankle joint being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating pressure to prevent lateral movement of the leg and foot relative to the boot, said tubular portions disposed at the back of the foot along the Achilles' tendon and at the top of the foot at the ankle joint being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, said tubular portions at the lower end of the leg, at the sides of the foot, and at the top of the foot forwardly of the ankle joint being substantially rigid after being inflated by the fluid to normal operating unit pressure, tubular portions at the malleoli of the foot being of toroidal shape, a tubular portion at the navicular bone of the foot being of toroidal shape.

18. An article of footwear comprising an inflatable bladder adapted to be disposed within a boot to bear against areas of a wearer's foot, said bladder including a plurality of adjacent chamber portions communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force on the foot; said bladder comprising a plurality of elastomeric sheets adhered together at spaced regions to provide said chamber portions between said regions.

19. An article of footwear comprising an inflatable bladder adapted to be disposed within a boot to bear against areas of a wearer's foot, said bladder including a plurality of adjacent chamber portions communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force on the foot; wherein said chamber portions extend lengthwise of the wearer's foot when disposed thereon, said bladder comprising elastomeric sheets overlying one another and adhered together along spaced longitudinal lines to provide said chamber portions.

20. An article of footwear as defined in claim 11; said bladder comprising opposed elastomeric sheets adhered together along spaced lines to provide all of said tubular portions.

21. An article of footwear as defined in claim 11; said tubular portions above the ankle joint, at the side of the foot, and at the top of the foot forwardly of the ankle joint being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating pressure to prevent lateral movement of the leg and foot relative to the boot, said tubular portions disposed at the back of the foot along the Achilles' tendon and at the top of the foot at the ankle joint being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, said tubular portions at the lower end of the leg, at the sides of the foot, and at the top of the foot forwardly of the ankle joint being substantially rigid after being inflated by the fluid to normal operating unit pressure, said bladder comprising opposed elastomeric sheets adhered together along spaced lines to provide all of said tubular portions.

22. An article of footwear as defined in claim 11; said tubular portions above the ankle joint, at the side of the foot, and at the top of the foot forwardly of the ankle joint being of such size and shape as to be substantially rigid after being inflated by a fluid to normal operating pressure to prevent lateral movement of the leg and foot relative to the boot, said tubular portions disposed at the back of the foot along the Achilles' tendon and at the top of the foot at the ankle joint being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, said tubular portions at the lower end of the leg, at the sides of the foot, and at the top of the foot forwardly of the ankle joint being substantially rigid after being inflated by the fluid to normal operating unit pressure, tubular portions at the malleoli of the foot being of toroidal shape, a tubular portion at the navicular bone of the foot being of toroidal shape, said bladder comprising opposed elastomeric sheets adhered together along spaced lines to provide all of said tubular portions.

23. An article comprising an inflatable bladder adapted to bear simultaneously against areas of a wearer's body and against a restraining member, said bladder including a plurality of adjacent chamber portions communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force against such areas, one or more of said chamber portions being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, one or more other chamber portions being substantially rigid after being inflated by the fluid to said normal operating unit pressure.

24. An article of footwear comprising an inflatable bladder adapted to be disposed within a boot to bear against areas of a wearer's foot, said bladder including a multiplicity of adjacent chamber portions communicating with each other and comprising a plurality of adjacent chamber portions disposed at the back of the foot, a plurality of said adjacent chamber portions being located on each side of the Achilles' tendon rearwardly of the ankle joint to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force on the foot.

25. An article of footwear as defined in claim 24; wherein said adjacent chamber portions on each side of the Achilles' tendon extend lengthwise of the wearer's foot when disposed thereon.

26. An article of footwear comprising an inflatable bladder adapted to be disposed within a boot to bear against areas of a wearer's foot, said bladder including a multiplicity of adjacent chamber portions communicating with each other and comprising a plurality of chamber portions disposed at the back of the foot on each side of the Achilles' tendon to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force on the foot; said bladder comprising a plurality of elastomeric sheets adhered together at spaced regions to provide said chamber portions between said regions.

27. An article of footwear comprising an inflatable bladder adapted to be disposed within the lower leg portion of a boot, said bladder including a multiplicity of adjacent chamber portions adapted to be disposed within the lower leg portion of the boot and communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated, said multiplicity of chamber portions including a plurality of chamber portions on each side of said lower leg portion of the boot.

28. An article of footwear as defined in claim 27; wherein said multiplicity of chamber portions extend lengthwise of the wearer's lower leg portion when disposed thereon.

29. An article of footwear as defined in claim 27; said bladder comprising a plurality of elastomeric sheets adhered together at spaced regions to provide said chamber portions between said regions.

30. An article of footwear as defined in claim 27; said multiplicity of chamber portions being constructed and arranged to encompass a major portion of the lower leg portion.

31. An article comprising an inflatable bladder adapted to bear simultaneously against areas of a wearer's body and against a restraining member, said bladder including a multiplicity of adjacent chamber portions communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated to exert an inward force against such areas, a first plurality of said adjacent chamber portions being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure, a second plurality of said adjacent chamber portions being substantially rigid after being inflated by the fluid to said normal operating unit pressure.

32. In combination: a restraining member adapted to encompass an area of the wearer's body; an inflatable bladder within said restraining member and including a multiplicity of adjacent chamber portions communicating with each other to provide uniform unit pressure in said portions when the bladder is inflated to exert an outward force against the restraining member and an inward force upon the area of the wearer's body, said multiplicity of chamber portions including a first plurality of said adjacent chamber portions at one side of said restraining member, and a second plurality of said adjacent chamber portions at another side of said restraining member.

33. In a combination as defined in claim 32; said first plurality of chamber portions being of such size and shape as to be deformable after being inflated by a fluid to normal operating unit pressure; said second plurality of chamber portions being of such size and shape as to be substantially rigid after being inflated by the fluid to said normal operating unit pressure.

Description:
The present invention relates to footwear, and more particularly to inflatable bladders insertable in boots, such as those used in sport activities, including skiing, hiking, skating, etc., and in the orthopedic and military fields.

Inflatable devices have been proposed for use in boots, such as in ski boots, to insure substantial rigidity between the boot and the foot of the wearer. Some of these inflatable boot designs employ a number of separate, relatively large cavities inflatable to different pressures through different valves. Such designs are relatively complex, the inflation of a plurality of different cavities being inconvenient. In addition, they tend to leak and do not maintain a preset pressure level. The relatively large cavities produce a soft spongy pressure, but do not give the desired feel and control between the foot and the boot, the foot being able to move laterally relative to the boot, which is a serious disadvantage in a boot designed for skiing.

The inflatable bladder of the present invention consists of a plurality of inflatable chambers, tubular portions or tubes of various sizes and geometry interconnected by a manifold, so that the unit gaseous pressure in all tubular portions or cavities will be the same. When inflated, some of the tubular portions are rigid; that is to say, substantially non-yielding; although others may be made of such cross-sectional dimensions as to be changed in volume as a result of movement of the foot, causing a reduction in cross-sectional area of some of the tubes and an inflation of other of the tubes, for the purpose of insuring the retention of the foot in the desired firm position within the boot, with a restraining force applied to the foot against movement within the boot in desired directions, as in lateral directions. The inflatable bladder not only provides extremely firm support and a desirable restraining force against the foot, but further provides firm and comfortable conformity to the irregular contour of the foot without imposing localized pressure on the bones, foot irregularities, and the like. The inflated bladder constantly forces the heel of the foot into the heel of the boot, and, at the same time, grasps the Achilles' tendon area of the foot to hold the heel of the foot in firm comfortable conformance to the boot, producing sensitive feel and control between the foot and, in the case of a ski boot, to the ski secured to the boot.

The inflated bladder also pushes essentially uniformly downwardly against the top of the foot, holding it in firm intimate contact with the sole of the boot at all times. When produced for skiing, the inflated bladder within the boot prevents relative lateral movement of the foot within the boot, permitting the foot and ankle muscles to move and flex to control forward and aft movement of the body and of the leg, thereby providing edge control of the skis without discomfort to the wearer.

A second collar portion of the inflatable bladder may also be provided, including a plurality of tubes and cavities interconnected by a manifold, or the like. Such portion, when inflated, rigidly supports the lower portion of the leg of the wearer. The collar portion can be provided in a ski boot to permit its pivoting in fore and aft directions relative to the lower foot portion, allowing the lower leg to pivot in the same directions. This inflatable collar portion firmly and comfortable grasps the lower leg above the ankle joint to hold the collar portion securely around the lower leg and aligned therewith. Accordingly, portions of the boot are free to rock back and forth, but restrained from rocking laterally, having the effect of significantly strengthening the ankle muscle control of the ski edgings. In a relaxed or neutral condition, the skis are held perpendicular to the lower legs and feet, relative lateral movement being prevented, retention of the bottom surfaces of both skis parallel to each other being enhanced. By enabling the skis to be held parallel, the exerting of small and uniform degrees of edge control permits the skier to control and guide the forward path of the skis and keep them from crossing or moving apart, which could cause the skier to fall.

The collar portion of the inflatable bladder also strengthens the leg muscles for fore and aft movement, requiring less muscular strain for the skier to hold the forward leaning or "running" position.

The inflatable bladder can be permanently affixed to the inside surface of the boot or shoe, be attached to the insole portion, or can be provided as a separate sock to be placed on the foot and in a conventional boot or shoe, which would be laced or buckled in a loose condition, the inflatable bladder then being inflated to the desired pressure.

A further aspect of the inflatable bladder embodying the present invention is to achieve any desired degree of rigidity between the inner and outer surfaces of the bladder, and to provide comfortable uniform force transfer capability between the foot and boot, without providing high pressure points or sponginess. Heavy loads, such as those sustained by an individual at the time of a fall, are distributed and transferred into the boot, ankle joint and leg in a smooth and uniform manner, eliminating severe concentrated stresses at the top of the boot, thereby reducing the probability of injury when the skier falls.

Another aspect of the inflatable bladder embodying the present invention is to eliminate the need for adjustable buckle or lacing devices in the shoe or boot, also eliminating the need for half sizes of shoes and boots to obtain a perfect fit.

The inflatable bladder further has the advantage of eliminating the need for massive boots in securing a perfect fit and controlled rigidity, permitting the boot to be manufactured in more graceful, form-fitting styles.

This invention possesses many other advantages, and has other purposes which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense.

Referring to the drawings:

FIG. 1 is an isometric view of a ski boot with an inflatable bladder therein, the ski boot and bladder being in an open condition;

FIG. 2 is an enlarged section taken along the line 2--2 on FIG. 1;

FIG. 3 is a section through a bladder inflatable gun and bladder valve mechanism, as disclosed in FIG. 2;

FIG. 4 is an isometric view of the bladder in an inflated condition around the foot and lower leg of a wearer disposed within a ski boot;

FIG. 5 is an enlarged fragmentary section taken along the line 5--5 on FIG. 4;

FIG. 6 is a cross-section taken along the line 6--6 on FIG. 1;

FIG. 7 is a view similar to FIG. 6 disclosing the ski boot secured in its closed condition;

FIG. 8 is an isometric view corresponding to FIG. 4, with the leg portion tilted forwardly of the foot portion around the ankle joint;

FIG. 9 is a view, in a single plane, of the inflatable bladder;

FIG. 10 is an enlarged section taken along the line 10--10 on FIG. 9;

FIG. 11 is an enlarged section taken along the line 11--11 on FIG. 9; and

FIG. 12 is a graph disclosing a plurality of curves showing the relationship between inflation pressures and diameters of the tubular portions of the inflatable bladder.

The specific boot or shoe illustrated in the drawings to exemplify the invention has been particularly designed for use in skiing. Essentially, it includes a main boot or foot portion 10 having an upper 11 and an outsole 12 that may be integral therewith. An upper collar portion 13 of the boot is pivotally secured to the main foot portion 10 by suitable pivot pins 14 on opposite sides thereof extending transversely of the collar and foot portion to permit fore and aft rocking of the collar portion relative to the main foot portion. The front portions of the collar and foot portion are split, with external longitudinal ribs 15 provided on opposite sides of the split, to permit separation or opening of the foot and collar portions, suitable clamps 16 being secured to the collar and foot portions at one side of the split for cooperation with the rib 15 on the opposite side of the split, for the purpose of drawing the opposed edges 17 defining the split together when the boot upper and the boot lower are to be closed.

Each clamp (FIGS. 6, 7) includes a body 200 pin connected to one end of a link 201, the other end of which is connected by a hinge pin 202 to a boot rib 15 at one side of the split. The body includes an end retainer portion 203 adapted to fit over the rib 15 at the other side of the split and engage its outer side. The clamp further includes an actuating arm 204 to which a bell crank lever 205 is pin connected, the intermediate heel 206 of this lever being adapted to engage the outer surface of the boot. A release lever arm 207 extends laterally outwardly for engagement by a person's finger when the clamp is to be released.

The clamp device is disclosed in an open condition in FIG. 6 and in a closed condition in FIG. 7. When the boot is to be closed, its edges 17 are pushed toward each other and the clamp shifted about its hinge pin 202 toward the rib 15 on the opposite side of the split, to place the retainer portion 203 over and beyond such rib. The actuating arm 204 is then pushed inwardly toward the shoe, which will cause the retainer portion 203 to draw the ribs 15 and the opposed edges 17 toward one another, until they are in the closed relation disclosed in FIG. 7, at which time the outer pin connecting the link 201 to the body 200 will have passed over center, in the nature of a toggle joint, to retain the clamp in its locked position, holding the boot closed about the foot and leg.

Each clamp is readily released by merely pressing inwardly on the release arm 207 of the bell crank lever, the heel 206 of which will pivot on the shoe as a fulcrum, and push the actuating arm 204 in an outward direction, the link 201 pivoting about the hinge pin to shift the retainer portion 203 away from the rib 15 which it engages. The clamp is released when the link 201 swings about the hinge pin 202 and passes over center, in the manner of a toggle joint.

The ribs 15 and clamps 16, by themselves, form no part of the invention claimed in the present case. It will be appreciated that other fastening devices can be used, such as adjustable buckles or laces.

The foot portion of the boot has the usual insole 18, that may be suitably affixed to the outsole 12, or which may be constituted as a separate member, as illustrated.

An inflatable bladder 20, made of a suitable elastomeric material, is adapted to be disposed around the foot, ankle and lower leg portions of the wearer, for supporting such portions by exerting a holding force thereon and against the confining foot and collar portions 10, 13 of the shoe. A developed view of the inflatable bladder is illustrated in FIG. 9. It comprises two plies 100, 101 of elastomeric sheet material, such as a non-porous, ether base, polyurethane sheeting, that is highly resistant to moisture degradation, extremely tough, and puncture resisting. Essentially, the inflatable bladder 20 is a sock-like member having a plurality of inflatable chambers, cavities or tubular portions formed between the two sheets of material interconnected by a manifold 21 to provide uniform fluid pressure in all regions of the bladder when inflated. As disclosed, the two sheets of material are adhered to one another along weld lines 22 and points 23 spaced from one another, to provide a plurality of tubular chambers 24, 25, 26, 27, 28, 29, 30, extending along, or disposed at, different portions of the foot, ankle joint and lower portion of the leg.

The bladder includes the upper, circumferential manifold 21 communicating with the upper ends of a plurality of longitudinal tubes 24 extending downwardly from the manifold along the lower portion of the leg toward the toes T of the foot. The bladder 20, when placed around the wearer's foot, ankle portion and lower leg, has a forward edge 31 at the lower end of the tubes 27, 28 terminating immediately behind the toes, the sole of the foot bearing against the insole 18, the bottom of the heel of the foot also bearing against the insole.

The type of thickness of the sheet material used, and the cross-sectional sizes of the tubes and cavities 24 to 28 (excluding two portions 29, 30 above the ankle and at the Achilles' tendon) are such that when the bladder is inflated to the desired pressure, such tubes and cavities will assume a substantially circular cross-sectional shape and will be rigid, resisting deformation even under comparatively high loads placed upon them by the wearer. However, the cross-sections of the tubes 29 above the ankle joint and of the Achilles' tendon tubes 30 are such that they can deform; that is, inflate and deflate so as to change the pressure area acting on the upper foot portion of the ankle joint, or the pressure area acting against the Achilles' tendon portion of the foot, as explained hereinbelow. Some of the tubes 24 at the sides of the lower portion of the leg open into intercommunicating concentric toroidal tubes or cavities 25 adapted to embrace the medial malleolus and lateral malleolus of the foot. Longitudinal tube portions below the inner or medial malleolus communicate with a toroidal tube 26 adapted to embrace the navicular region of the foot.

If desired, the side portions 32 of the bladder may be disposed under the side margins 33 of the insole and suitably glued or otherwise adhered thereto. However, a forward portion 31 of the bladder and the heel portion 34 below the Achilles' tendon area 30 are open, allowing the toes to bear, through the sock of the wearer, against the insole 18, and the heel to bear, through the sock of the wearer, against the underlying portion of the insole.

It is to be noted that all of the tubes and cavities communicate with one another, the upper ends of the tubes 24 opening into the manifold 21. Inflation of the bladder can be accomplished through a valve 40 opening into the manifold 21, or, as specifically illustrated, into any one of the tubes 24, such as a rear tube adjacent to the manifold. A valve body 41 is secured to an elastomer support plate 42 suitably attached to and sealed with the inner surface of the outer layer 100 of one of the tubes, the inner part of the valve body having a circumferential groove 43 in which the plate is received. The valve body has a central outer passage 44 and a pierced inner passage portion 45 communicating with the interior of the tube, the elastomeric material of the valve inherently constricting and normally retaining the pierced passage portion 45 closed. The valve body 41 extends through an enlarged rear opening 46 in the boot collar 13 for reception of a suitable inflating and deflating gun 47a.

Inflation and deflation of the bladder can be accomplished in a known manner through use of a suitable needle 47 having a central passage 48 therein closed at its inner end 49, where a side port 50 communicates with the needle passage. The needle also has a deflating port 51 spaced substantially from the other port 50. The outer end of the needle is threaded into a gun case or housing 52 which has an outlet 53 opening into a transverse passage 54 surrounded by a valve seat 55. A transversely located valve stem 56 is slidable laterally in the transverse passage 54, an outer enlarged portion 57 of the valve stem engaging a suitable side seal 58 mounted in the housing to prevent fluid leakage along the valve stem. A reduced diameter portion 59 of the valve stem is suitably secured to a valve head 60 carrying a gasket seal 61 adapted to engage the valve seat 55 when the passage 53, 54 is to be closed. A helical compression spring 62 bears against the housing and a button 63 at the outer end of the valve stem to normally retain the valve head engaged with its seat. Depression of the button against the force of the spring shifts the valve head from its seat, allowing gas under pressure to flow into the transverse passage 54 and the outlet passage 53.

The gas under pressure may be provided from a suitable source. As shown, a carbon dioxide cartridge 64 is contained within a suitable chamber 65 in the housing 52, which is closed by an end cap 66 threadedly secured to the housing, the end cap bearing against the cartridge for the purpose of pressing its forward end wall 67 against the tapered or pointed end 68 of a needle 69 disposed within a socket 70 in the housing. A suitable side seal 71 carried by the housing makes a slidable seal with the cylindrical neck portion 72 of the cartridge, such that partial unthreading of the cap 66, after the end wall 67 of the cartridge has been pierced by the needle point 68, will retract such end wall from the tapered point and permit the gas under pressure in the cartridge to flow through a housing inlet passage 73 into a housing cavity 74 communicating with the transverse passage 54 when the valve is open. When a cartridge is to be replaced, further unthreading of the cap 66, but prior to its complete unthreading from the housing 52, will allow the neck 72 of the cartridge to move off the side seal ring 71, permitting any gas under pressure in the cartridge to exhaust through vent ports 75 in the housing to atmosphere. After this occurs, the cap 66 can be completely unthreaded from the housing in a safe manner for replacement of the cartridge 64.

The hollow needle 47 is inserted in the valve passage 44, 45, a reduced diameter forward housing portion 76 moving over the valve 41 and within the boot opening 46. The tapered end 49 of the needle will engage the pierced passage portion 45 and spread it apart to locate the inner port 50 against a reinforcing pad 77 secured to the opposed wall 101 of a tube 24. When the needle is fully inserted within the valve, the inner port 50 is in open communication with the tube, but the deflating port 51 is confined within the elastomer valve body 41, which closes it. Accordingly, when the button 63 is depressed to open the housing valve, the gaseous medium will flow through the hollow needle into the tube 24, which is in communication with all other tubes and cavities of the bladder, to inflate the bladder to the desired pressure, after which the needle 47 is withdrawn completely from the valve, the pierced portion 45 of the latter inherently constricting to its closed condition.

It is apparent that the bladder 20 will first be placed around the foot, ankle and lower leg portion of the wearer and located in the boot, after which the boot will be closed through use of the clamps 16, preferably before inflation of the bladder to the desired pressure occurs.

With the tubes and cavities of the bladder inflated to the desired pressure, they achieve an operationally rigid state, unless the unit pressure within certain of the tubes is increased beyond a predetermined point to effect their deformation. As described above, the cross-sections of all tubes and the manifold, with the exception of the Achilles' tendon tubes 30 and the tube portions 29 above the ankle joint, are such that the predetermined maximum internal pressure is not exceeded. During skiing operations, however, fore and aft movements of the leg about the ankle joint as a pivot can produce sufficient deformation of the tubes 29 above the ankle, or the Achilles' tendon tubes 30, as to change their volume, thereby effecting increase in the unit gas pressure within the bladder. The inflation and deflation of the tubes 29 above the ankle and of the Achilles' tendon tubes 30 are taken advantage of, since it will increase the area of such tubes bearing upon the foot, holding the foot firmly downwardly against the sole of the boot. Such fore and aft movement is permitted by the pivoting of the collar portion 13 of the boot with respect to the foot portion 10. However, the other tubes and cavities 24 to 28 remain undeformed and rigid, holding the foot in laterally rigid relation within the boot, preventing relative lateral movement of the foot therewithin.

The graph in FIG. 12 discloses the relationship between the unit pressure within an elastomeric tube and the diameters of the tube, the tube wall thickness being the same. As shown in curves 200 and 201, each elastomer tube or cavity will change from its deflated condition to an inflated condition under relatively low pressure 300, but will then retain substantially the same diameter as the pressure increases up to a certain value, as indicated by the points P1 and P2 in the chart. Further increase in pressure will effect inflation and expansion of the tubular diameter (see curve 201), the wall thickness becoming thinner and thereby causing the pressure to drop as the diameter increases.

Thus, in the chart, it is evident that over a substantial pressure range (1 to 24 psi in curve 200; 1 to 11 psi in curve 201) a tube remains essentially constant in diameter, each tube depicted in the curves being essentially rigid in its particular range. Bladders made in accordance with the present invention have had sheet or wall thicknesses of from 0.010 to 0.020 inches, the pressure at which the bladder has been inflated being from about 8 to 16 psi, depending upon the desires of the wearer to secure a firm and comfortable retention of the foot and lower leg in the boot. With such pressure, all tubes and cavities will be rigid. The diameters of the Achilles' tendon tubes 30 and the tubes 29 above the ankle have been made greater than the other tubes, so that a change in pressure, as a result of fore and aft movement, can effect expansion and contraction of the tubes 29 and 30 to exert the desired increased downward restraining force on portions of the foot at the heel and forwardly of the ankle. By having the chambers or cavities 29, 30 above the ankle and in the Achilles' tendon region operating at near their elastic deformation limit P2, localized forces in one of these areas can cause control pressure migration of the other area. When the skier bends severely forwardly in the avante position, the forward high stress tubes or cavities 29 are partially collapsed, which increases the internal pressure of the bladder. This has no effect on the rigid tubes and cavities 21, 24 to 28 (curve 200), but such higher internal pressure in the Achilles' tendon area tubes 30 at the heel causes them to elastically expand and create an increased downward and inward force to more firmly hold the heel of the foot down into the heel of the boot. At the same time, the heel would be attempting to lift out of the boot, increasing the pressure in the Achilles' tendon tubes, such increased pressure feeding back to the forward ankle tubes 29 to keep such tubes from collapsing.

In the event that a reverse skiing technique is employed, as by a skiing champion, of leaning backwards, the tubes 29 above the ankle and the Achilles' tendon tubes 30 would operate in the opposite manner to that described above to press the sole and heel of the foot more firmly against the sole of the boot.

One manner of producing the inflatable bladder 20 is to provide two sheets of transparent material of the required thickness and hardness. Heat absorbent opaque material is then placed on one sheet of material along the desired lines 22 and points 23 of fusion or adherence of the sheets of material to one another to form the intervening tubes and cavities 21, 24 to 30, after which the other sheet of material would be placed thereover, the valve 40 and plates 42, 77 having previously been located and mounted in place. This sandwich is then subjected to visible and infra-red radiation energy, such radiation passing through the transparent portions of the sheets without effecting their heating substantially but being absorbed and converted to thermal energy along the locations of the opaque material, heating the sheets of material along such opaque regions 22 to the degree at which they fuse or weld securely and in leakproof fashion to one another. The bladder structure thus formed can then be trimmed to the desired shape, such as illustrated in FIG. 9.

As described above, the inflated bladder 20 can then be formed into a sock-like member, with the forward edges 17a, 17a separated and the lower margins 32 underlying and adhered to the insole 18 of the boot. The bladder and insole are then placed within the boot, the side edges 17a being in substantial alignment with the side edges 17 of the boot. The wearer then inserts his foot into the liner and boot, locking the boot through aid of the clamps 16. The bladder 20 is then inflated to the appropriate pressure to form the rigid tubes and cavities 24 to 28 and the normally rigid Achilles' tendon tube portions 30 and forward ankle tubes 29, which, however, as described above, can contract and inflate in a controlled fashion under the fore and aft movement of the wearer's leg.

If desired, the inner layer 101 of sheet material can be covered with a layer of suitable resilient material 110, such as a cellular polyurethane, readily yieldable and comformable foam, which, in turn, is covered by an inner liner 111 of lamb's wool, or the like. With such intervening layers of material between the inflatable bladder 20 and the sock on the person's foot, comfort and conformance to the foot, ankle and lower leg portion are achieved.

It is thus apparent that an inflatable bladder has been provided for use within a boot that gives controlled support to the leg, ankle and foot of the wearer. More specifically, relative lateral motion between such parts and the encompassing boot and the ski attached thereto in a lateral direction may be prevented, while controlled fore and aft movement of the leg is secured without permitting the sole and heel of the foot to lift from the sole of the boot.

It is to be noted that the major number of tubes run lengthwise of the leg and foot. Accordingly, when inflated, the pressure applied by the tubes to the foot cannot arrest or materially restrict the arteries, veins and blood vessels feeding various regions of the leg, ankle and foot.

Deflation of the bladder, to permit removal of the foot from the boot, can occur readily by inserting the hollow needle 47 through the valve passages 44, 45 with the inner port 50 extending into a tube 24 and with the deflating port 51 located externally of the valve body 41, such that the gas in the bladder can exhaust through the hollow tube 47 to the exterior of the valve body 41, and, if the cartridge gun 52 is used, exhausting through housing ports 76a to the atmosphere.

With the bladder in its substantially flat condition, as disclosed in FIG. 9, its inflation causes it to inherently assume a compound curved shape conforming generally to the shape of the foot and lower leg of the wearer. This result is believed to be due to the longitudinal and lateral arrangement of the tubes that result in different extents of cross-wise contraction of the bladder from top to bottom as it is inflated.