Inflatable member for compression foot cuff
View Patent ↗A foot cuff that is inflatable to apply compression to the foot to promote blood flow has a bladder formed of two layers of material secured together. An outer layer includes a foot-underlying portion that has a greater thickness and rigidity that an opposing inner layer. The outer layer directs expansion of the bladder upon inflation in the direction of the inner layer and toward the foot for increasing compressive force applied to the foot.
1. An inflatable bladder for use in a compression foot cuff configured to be secured to a foot of a wearer, the inflatable bladder comprising:
a fluid-impermeable inner bladder layer for being positioned adjacent to a foot of a wearer;
a fluid-impermeable, integrally formed outer bladder layer secured in opposing relation to the inner bladder layer to define an inflatable chamber;
wherein the inner and outer bladder layers define a foot-underlying portion of the bladder that underlies the wearer's foot when the compression foot cuff is secured to the foot of the wearer, and a wing portion extending laterally outwardly from the foot-underlying portion;
wherein a thickness of the outer bladder layer at the foot-underlying portion is greater than a thickness of the inner bladder layer to provide rigidity to the outer bladder layer so that the inflatable chamber expands more toward the wearer's foot than away from wearer's foot when the foot cuff is secured to the wearer's foot, and the thickness of the outer bladder layer at the foot-underlying portion is greater than a thickness of the outer bladder layer at the wing portion so that the wing portion of the inflatable bladder is more flexible than the foot-underlying portion of the outer bladder layer to wrap around a superior portion of the wearer's foot, wherein the outer bladder layer has a rib formed on an inner surface of the outer bladder layer to resist bending of the outer bladder layer and wherein the rib forms a groove in an outer surface of the outer bladder layer;
wherein the inner bladder layer and outer bladder layer are secured to each other along a line extending generally adjacent to perimeter of the inflatable bladder, the groove and rib being formed on the outer bladder layer separately from the line connecting the inner bladder layer to the outer bladder layer, the rib and groove extending only partially along the perimeter of the inflatable bladder such that the rib and groove extend a lesser distance along the perimeter than the line and extend only along the foot-underlying portion of the inflatable bladder.
2. An inflatable bladder as set forth in claim 1 wherein the thickness of the outer bladder layer at the foot-underlying portion is at least three times greater than the thickness of the inner bladder layer.
3. An inflatable bladder as set forth in claim 2 wherein the thickness of the outer bladder layer at the foot-underlying portion is at least about ten times greater than the thickness of the inner bladder layer.
4. An inflatable bladder as set forth in claim 1 wherein the thickness of the outer bladder layer at the foot-underlying portion is at least about 1.5 times greater than the thickness of the outer bladder layer at the wing portion.
5. An inflatable bladder as set forth in claim 4 wherein the thickness of the outer bladder layer at the foot-underlying portion is at least about five times greater than thickness of the outer bladder layer at the wing portion.
6. An inflatable bladder as set forth in claim 1 further comprising a fluid inlet port extending outward from the outer bladder layer for connection to a source of pressurized fluid, the inlet port defining a conduit in fluid communication with the inflatable chamber for delivering pressurized fluid to the inflatable chamber.
7. An inflatable bladder as set forth in claim 6 wherein the outer bladder layer and the inlet port are molded as a one-piece, integral unit.
8. An inflatable bladder as set forth in claim 7 wherein the inlet port has a longitudinal axis and defines a connecting opening on an exterior of the inflatable bladder, the longitudinal axis extending through the connecting opening and generally parallel to the outer bladder layer, the connecting opening having an oblong cross-sectional shape taken transverse to the longitudinal axis so that the inlet port has a low profile with respect to the outer bladder layer.
9. An inflatable bladder as set forth in claim 8 wherein the outer bladder layer and the inner bladder layer define a wing portion of the inflatable bladder extending laterally outward from the foot-underlying portion and wrapping around a superior portion of the wearer's foot when the compression foot cuff is secured to the foot of the wearer, wherein the thickness of the outer bladder layer at the foot-underlying portion is greater than the thickness of the outer bladder layer at the wing portion.
10. An inflatable bladder as set forth in claim 1 further comprising a securement opening extending through the inner and outer bladder layers adjacent to a perimeter edge of the foot-underlying portion of the bladder.
11. An inflatable bladder as set forth in claim 10 in combination with an envelope including an outer cover and an inner liner, the inflatable bladder being disposed between the outer cover and inner liner in the envelope, wherein at least one of the outer cover and the inner liner extends into the securement opening and is secured to the other of the outer cover and inner liner to fix a position of the inflatable bladder with respect to the envelope.
12. An inflatable bladder as set forth in claim 11 wherein the securement opening comprises a plurality of securement openings.