[0001] This invention relates to footwear and more particularly to sole units for boots
and shoes.
[0002] According to this invention there is provided a sole unit for an article of footwear
which sole unit has a sole portion and a heel portion and is moulded from a resilient
material, a plurality of cavities formed in the upper surface of the sole portion
and heel portion of the unit, a system of channels formed in the unit, which channels
interconnect the cavities, and a bulge formed on the bottom surface of the sole unit
at the location of each of said cavities.
[0003] According to a preferred feature of the invention the mouth of each of the cavities
has a reduced cross-sectional area where it opens to the associated channel or channels.
The said reduced cross-sectional area may for example be approximately one-quarter
of the maximum cross-sectional area of the cavity.
[0004] The invention also provides an article of footwear comprising an upper, a sole unit
to which the upper is connected, and a porous insole or sock overlying and bonded
to the top surface of the sole unit, which sole unit has a sole portion and a heel
portion and is -moulded from a resilient material, a plurality of cavities formed
in the upper surface of the sole portion and heel portion of the unit, a system of
channels formed in the unit, which channels interconnect the cavities, and a bulge
formed on the bottom surface of the sole unit at the location of each of said cavities.
[0005] One embodiment of the invention will now be described by way of example with reference
to the accompanying diagrammatic drawings in which:
Figure 1 is a sectional view of a shoe having a sole unit according to the invention,
Figure 2 shows a plan view of the sole unit of the shoe of Figure 1, and
Figure 3 shows an enlarged view of one of the cavities.
[0006] Referring to the drawings there is shown a shoe 10 the upper 11 of which is lasted
to an insole 12 made from leather, or a permeable plastics material or other suitable
permeable material. A moulded sole unit 13 is bonded to the insole and lasting margin
14 of the upper.
[0007] The sole unit is moulded from a resilient plastics material such as foamed polyurethane
and has a multiplicity of cavities 15 opening to the top surface of the unit and interconnected
by a series of channels 16 which are also open to the top surface of the unit. The
cavities are grouped chiefly in the middle of the sole area and the middle of the
heel area of the unit, and at least two channels communicate with each cavity. The
cavities are somewhat egg-shaped and there is a bulge 17 on the bottom surface of
the sole unit at the location of each cavity, so that the pressure exerted by the
foot on any bulge expels air from the associated cavity, and the action of walking
pumps air from one cavity to another along the channels and in this way absorbs the
shocks of impact of the foot with the ground. At the same time perspiration from the
foot of the wearer can pass through the pores of the insole and be evaporated by the
air flow along the channels, so that improved dispersion of the perspiration is achieved.
[0008] Each cavity has a reduced cross-section where it joins the channels so that a neck
18 is formed which tends to restrict the rate of flow of air into and out of the cavities.
In the illustrated construction the diameter of the cavity at the neck is approximately
half of the maximum diameter of the cavity. The maximum diameter is typically in the
range 8 to 12 mm.
[0009] The bulges on the underside of the sole unit may have a height of 6 to 8.mm.
1. A sole unit for an article of footwear which sole unit has a sole portion and a
heel portion and is moulded from a resilient material, a plurality of cavities formed
in the upper surface of the sole portion and heel portion of the unit, a system of
channels formed in the unit, which channels interconnect the cavities, and a bulge
formed on the bottom surface of the sole unit at the location of each of said cavities.
2. A sole unit as claimed in claim 1, wherein each of the cavities communicates with
the channel system through a restricted opening.
3. A sole unit as claimed in claim 2, wherein the cross-sectional area of said restricted
opening --is substantially one-quarter of the maximum cross-sectional area of the
cavity.
4. An article of footwear comprising an upper, a sole unit to which the upper is connected,
and a porous insole or sock overlying and bonded to the top surface of the sole unit,
which sole unit has a sole portion and a heel portion and is moulded from a resilient
material, a plurality of cavities formed in the upper surface of the sole portion
and heel portion of the unit, a system of channels formed in the unit, which channels
interconnect the cavities, and a bulge formed on the bottom surface of the sole unit
at the location of each of said cavities.
5. An article as claimed in claim 4, wherein each of the cavities communicates with
the channel system through a restricted opening.
6. An article as claimed in claim 5, wherein the cross-sectional area of said restricted
opening is substantially one-quarter of the maximum cross-sectional area of the cavity.
7. An article as claimed in any one of claims 4 to 6, wherein a multiplicity of said
cavities are provided and include concentrations in the fore part and in the heel
portion of the sole unit.
8. An article as claimed in any one of claims 4 to 7, wherein each of said cavities
has at least two channels of the channel system connected thereto.
9. An article as claimed in any one of claims 4 to 8, wherein the maximum diameter
of the cavities is in the range 8 to 12 mm.
10. An article as claimed in any one of claims 4 to 9, wherein the bulges on the bottom
surface of the sole unit have a height in the range 6 to 8 mm.