Polyurethane injected boot assembly and associated manufacturing method
A footwear assembly having an upper that comprises a neoprene sock with a foot portion integrally connected to a leg portion. The foot portion has heel, vamp and under-foot portions. The leg portion has front shin, side wall, and rear calf-side portions. The upper has a unitary, outer, injection molded layer molded directly onto the foot and shin portions of the neoprene sock, while the sidewall and rear calf-side portions remain substantially uncovered by the injection molded layer. The injection molded layer encases the foot portion of the neoprene sock. The injection molded layer on the shin portion defines a shin guard portion having a necked down area integrally connected to the injection molded layer at the vamp portion, wherein the shin guard extends upwardly from the necked-down portion in an outwardly diverging shape away from the vamp.
1. A footwear assembly, comprising:
an outsole; and
an upper connected to the outsole, the upper comprising—
a sock layer having—
a leg portion having a front shin portion, side wall portions and a rear calf-side portion; and
a foot portion integrally connected to the leg portion and having a vamp portion and an underfoot portion;
a shank between the outsole and a bottom of the foot portion of the sock layer; and
a unitary outer injection molded layer molded directly onto at least a portion of the sock layer, wherein the unitary outer injection molded layer comprises—
a first injection molded region that encases the foot portion of the sock layer, wherein the first injection molded region fully covers the vamp portion and the under-foot portion, and wherein the first injection molded region covering the under-foot portion is between the sock layer and the outsole forming an integral, compressible midsole portion that encases the shank; and
a second injection molded region integrally connected to the first injection molded region and extending upwardly from the foot portion toward the leg portion of the sock layer, wherein the second injection molded portion is molded over at least a portion of the shin portion of the leg portion.
2. The footwear assembly of claim 1 wherein the upper further comprises at least one of a toe guard encapsulated by the first injection molded region, a metatarsal guard encapsulated in the first injection molded region, a puncture resistant insole disposed between a portion of the first injection molded region and the outsole, and a snake-guard layer coupled to the sock layer.
3. The footwear assembly of claim 1 wherein injection molded layer has a thickness of approximately 6.0 mm in the vamp portion.
4. The footwear assembly of claim 1 wherein the injection molded layer has a plurality of integral convertible channels of reduced thickness around the ankle portion, wherein the convertible channels define cut lines along which the upper may be cut during manufacture to define a selected height of the leg portion.
5. The footwear assembly of claim 1 wherein the second injection molded portion is attached to the front shin portion and defines a shin guard integrally connected to the first injection molded portion at the vamp portion.
6. The footwear assembly of claim 1 wherein the sock is a neoprene sock.
7. The footwear assembly of claim 1 wherein the sock layer has a thickness of about 3.5 mm and the injection molded layer has a thickness at the vamp portion of approximately 6.0 mm.
8. The footwear assembly of claim 1 wherein the injection molded layer is a polyurethane material or a Styrene Ethylbutylene Styrene material.
9. The footwear assembly of claim 1 , further comprising a toe guard encapsulated by the injection molded layer.
10. The footwear assembly of claim 1 wherein the leg portion of the upper comprises a gusset on the calf side-portion.
11. The footwear assembly of claim 1 , further comprising a puncture resistant layer positioned between the under-foot portion of the sock layer and at least a portion of the injection molded layer.
12. The footwear assembly of claim 11 wherein the puncture resistant layer comprises an encapsulated puncture resistant insole board.
13. The footwear assembly of claim 11 wherein the puncture resistant layer is stitched to the sock layer.