Technical Field
[0001] The invention is related to a shoe sole comprising a heel area and a ball area, an
insole, an outsole configured to come into contact with the ground, a midsole between
the insole and the outsole, an elastic insert embedded into the midsole in the heel
area of the shoe sole and an anti-puncture sheet. The invention is further related
to a safety shoe comprising said shoe sole.
Background Art
[0002] Safety shoes, or anti-injury shoes, offer their users a high degree of protection
against puncture wounds and crushing injuries. All safety shoes, in order to respect
the current standards of the field, comprise an upper provided with a sufficiently
rigid protective toe cap to withstand impacts, protecting the user's toes from crushing.
Further, the safety shoes are provided with puncture resistant sheet, which prevents
sharp objects, such as nails, to penetrate through the shoe sole. Safety shoes are
usually used as working shoes, whereby they are intended to be worn by the user for
many hours per day in activities, in which the user is in continuous movement. Therefore,
the safety shoes must be to be able to ensure a satisfactory level of comfort for
the user. For this purpose, many safety shoes are equipped with a layered sole comprising
an insert made of elastic material. The elastic insert makes it more comfortable to
stand on the floor and it provides a soft and dynamic shock absorption during walking.
Although such anti-injury shoes have been successful with users and are currently
very common, they are not without drawbacks.
[0003] Document
EP 3648628 B1 discloses a safety shoe, comprising a layered sole having an upper layer, an intermediate
layer and a lower layer adapted to come into contact with the ground. In the intermediate
layer an elastic insert is embedded, which extends exclusively at the rear zone of
said sole. The upper layer comprises an anti-puncture sheet thoroughly covering the
sole and overlapping the elastic insert. The anti-puncture sheet is preferably made
of non-metallic, flexible material, apparently to preserve softness and comfort of
use offered by the elastic insert. However, soft and flexible anti-puncture sheets
do not provide maximum protection against punctures, whereby protection of the user's
feet is compromised.
[0004] Document
KR 20070117233 A discloses a shock absorbing safety shoe comprising an insole, an outsole, a midsole
between the insole and the outsole midsole, a protective plate installed in the midsole
and a shock-absorbing member. The shock absorbing member includes a coil spring acting
as an elastic body. In the heel area of the shoe the protective plate is above the
shock absorbing member, which reduces the cushioning effect of the shock-absorbing
member.
[0005] Document
WO 2021124068 A1 discloses a puncture resistant sole comprising a midsole, a shock absorbing insert
and a puncture resistant sheet interposed between the insert and midsole. The sole
can further comprise an inner insole above the puncture resistant sheet, which inner
insole can be equipped with small ventilation holes in the forefoot area of the sole.
[0006] An object of the invention is to provide shoe sole and a safety shoe, in which drawbacks
relating to the prior art are reduced.
[0007] The object of the invention is achieved with a shoe sole and a safety shoe, which
are characterized in what is disclosed in the independent patent claims. Some preferred
embodiments of the invention are disclosed in the dependent claims.
Summary of the invention
[0008] The shoe sole according to the invention comprises a heel area and a ball area, an
insole, an outsole configured to come into contact with the ground, a midsole between
the insole and the outsole, an elastic insert embedded into the midsole extending
in the heel area of the shoe sole and an anti-puncture sheet. The anti-puncture sheet
has a front portion locating between the insole and the midsole in the ball area of
the shoe sole and a rear portion locating between the outsole and the elastic insert
in the heel area of the shoe sole.
[0009] In some embodiments of the shoe sole according to the invention the anti-puncture
sheet further comprises a middle portion connecting the front portion and the rear
portion, which front portion, middle portion and rear portion are made of same material.
[0010] In some embodiments of the shoe sole according to the invention the anti-puncture
sheet is a shaped metal plate, preferably a shaped steel plate.
[0011] In some embodiments of the shoe sole according to the invention the anti-puncture
sheet has an upper surface facing the insole and a lower surface facing the outsole
and the front portion of the anti-puncture sheet is attached to the insole and the
rear portion of the anti-puncture is attached to the elastic insert. Preferably, the
upper surface of the front portion of the anti-puncture sheet is attached to the insole
by gluing and the upper surface of the rear portion of the anti-puncture sheet is
attached to the elastic insert by gluing.
[0012] In some embodiments of the shoe sole according to the invention the midsole is attached
to the lower surfaces of the front portion and the rear portion of the anti-puncture
sheet. Preferably, the midsole is made of and attached to the anti-puncture sheet
by moulded polyurethane material.
[0013] In some embodiments of the shoe sole according to the invention the upper surface
and the lower surface of the anti-puncture sheet are covered with a primer for enhancing
the attachment of the midsole to the anti-puncture sheet.
[0014] In some embodiments of the shoe sole according to the invention the insole has hole
in the heel area of the shoe sole, the hole exposing a major part of the surface of
the elastic insert facing the insole.
[0015] The safety shoe according to the invention comprises a shoe sole according to any
embodiment of the invention explained above and an upper attached to the shoe sole.
Preferably, the upper comprises a protective cap covering the tip of the ball area
of the shoe sole.
[0016] An advantage of the invention is, that the softness of the shoe sole and comfort
of use of the shoe is good without compromising the puncture resistance of the shoe
sole.
[0017] Another advantage of the invention is, that the elastic insert is protected against
penetrating of puncturing sharp objects, which ensures, that the integrity and elastic
properties of the insert are not weakened.
Brief Description of the Drawings
[0018] In the following the invention will be described in detail, by way of examples, with
reference to the accompanying drawings in which,
- Fig. 1
- depicts an example of an exploded safety shoe according to the invention as a side
elevation view and
- Fig. 2
- depicts the safety shoe of figure 1 as an overall side elevation view.
Detailed Description
[0019] In figure 1 an example of a safety shoe according to the invention is shown as an
exploded side elevation view. The safety shoe according to the invention comprises
an upper 50 and a layered shoe sole 10 attached to the upper. The upper is equipped
with a protective cap 52 satisfying the current safety standards for protecting the
user's toes from crushing, when an impact or a pressing force effects on the shoe
tip. The shoe sole has a heel area 11 for supporting the heel of the user and a ball
area 12 for supporting the forefoot, i.e. the ball and toes of the user when the shoe
is worn.
[0020] The layered shoe sole 10 comprises an insole 14, an outsole 16 configured to come
into contact with the ground and a midsole 15 between the insole and the outsole.
The insole, which is configured to face the user's feet, when the shoe is worn, is
a flexible sheet-like element, which is preferably made of heavy paper or thick nonwoven
fabric. In the heel area 11 of the insole there is hole 28 extending through the insole
exposing the elastic insert 18 below the insole as explained later.
[0021] The outsole 16 is preferably made of rubber or other similar material. The outer
surface of the outsole, which is configured to come into contact with the ground has
an uneven surface shaping for providing sufficient friction between the outsole and
the ground.
[0022] The midsole 15 is made of injection molded polyurethane. An elastic insert 18 is
embedded into the midsole in the heel area of the sole during manufacturing phase
of the midsole. The elastic insert is a flexible and compressible element which is
at least partly, preferably fully, made of foamed thermoplastic polyurethane. The
elastic insert extends only to the heel area of the shoe sole covering 30-50 %, preferably
35-40 % of the overall length of the shoe sole 10. The width of the elastic insert
is substantially equal to or slightly less than the width the midsole in the heel
area 11 of the shoe sole. The lateral dimensions of the elastic insert are slightly
larger than the lateral dimensions of the hole 28 in the insole above the elastic
insert. The thickness of the elastic insert is between 15-25 mm, preferably substantially
20 mm.
[0023] The midsole 15 comprises a window 20 on both side surfaces of the midsole in the
heel area of the shoe sole. The elastic insert is partly visible through these windows.
The windows allow the elastic insert to slightly protrude outward through the windows
assisting the deformation of the elastic insert material during compression. This
increased deforming capacity enhances the ability to elastically absorb the forces
deriving from the weight of the user during walking. The size and shape of the window
is smaller than the side surface of the elastic insert facing the window, whereby
only a part of the elastic insert is visible through the windows. Apart from the area
of the windows the midsole surrounds the sides of the elastic insert.
[0024] The shoe sole further comprises an anti-puncture sheet 22, which extends inside the
shoe sole near to the outer edges of the shoe sole for protecting the user's foot
sole against protruding sharp objects, such as nails, when the shoe is worn. The anti-puncture
sheet 22 has an upper surface facing the insole 14 and a lower surface facing the
outsole 16 and it is made of steel sheet having a thickness 0,6-1,0 mm, preferably
0,8 mm. The anti-puncture sheet is shaped from a single metal sheet and it has a front
portion 24 covering substantially the ball area 12 of the shoe sole, a rear portion
26 covering substantially the heel area 11 of the shoe sole and a middle portion 25
connecting the front and rear portions. The front and the rear portions are substantially
even areas, which lie in different planes and the middle portion is in inclined position
in relation to the front and rear portions. The height of the middle portion is substantially
equal to the thickness of the elastic insert 18. The upper surface and the lower surfaces
of the anti-puncture sheet are covered with a primer for enhancing the attachment
of the midsole to the anti-puncture sheet. Preferably the primer has conductive properties,
which help the shoe to satisfy the antistatic requirements stated in the safety shoe
standards.
[0025] In figure 2 the safety shoe of figure 1 is shown as a side elevation view. The front
portion 24 of the anti-puncture sheet 22 is attached directly to the insole by gluing
and the rear portion 26 of the anti-puncture sheet is attached to the lower surface
of the elastic 18 insert also by gluing. The midsole 15 is attached directly to all
surfaces of the anti-puncture sheet, which are not in direct contact with the elastic
insert or the insole, these surfaces including the lower surfaces of the front portion
and the rear portion of the anti-puncture sheet. The midsole attaches also to the
upper 50 with a protective cap 52, the outsole 16 and those parts of the lower surface
of the insole 14, which are not in direct contact with the elastic insert or the anti-puncture
sheet. The midsole also surrounds the sides of the elastic insert 18 apart from the
area of the windows. The midsole is made of polyurethane material by injection moulding,
whereby the midsole attaches to the elastic inset, insole, anti-puncture sheet and
to the outsole through the adhesive force of the polyurethane material.
[0026] When safety shoes are used, a major part of the weight of the user exerts to the
heel area of the shoe sole, especially during walking. In the safety shoe according
to the invention the front portion of the anti-puncture sheet is locating between
the insole and the midsole in the ball area of the sole. In in the heel area of the
shoe sole the rear portion of the anti-puncture sheet is locating between the outsole
and the elastic insert. Between the outsole and the rear portion of the anti-puncture
sheet there is a layer of midsole material, i,e. polyurethane. Thus, in the heel area
of the shoe sole 10 there is a cushioning elastic insert 18 between the anti-puncture
sheet 22 and the upper surface of the shoe sole facing the user's feet. Therefore,
in the heel area, the substantially rigid anti-puncture sheet does not deteriorate
the cushioning effect of the elastic insert. Further, in the insole there is a hole
28 in the heel area of the shoe sole, which hole exposes a major part of the upper
surface of the elastic insert facing the insole. Thus, in the area of the hole the
upper surface of the elastic insert constitutes the uppermost surface of the shoe
sole, whereby forces and impacts exerting through the heels of the user affect directly
to the elastic insert providing maximal cushioning effect.
[0027] The shoe sole must be flexible enough in the longer direction sole to facilitate
comfort walking with the shoe. The metallic anti-puncture sheet 22 inevitably makes
the shoe sole stiffer. The stiffening effect of the anti-puncture sheet enhances,
if the anti-puncture sheet bends in the transverse direction of the shoe sole because
of uneven working surface for example. In the shoe sole according to the invention
there is a clear angle or fold between the rear portion 26 and the middle portion
25 and between the middle portion and the front portion 24 of the anti-puncture sheet.
These angles or folds extend straight from one side of the anti-puncture sheet to
the opposing side of the anti-puncture sheet. These straight deformation lines act
as integral elastic hinges, which enhance bending of the anti-puncture in the longer
direction of the shoe sole.
[0028] Some preferred embodiments of shoe sole and the safety shoe has been disclosed above.
The invention is not limited to the solutions explained above, but the invention can
be applied in different ways within the limits set by the patent claims.
Reference Signs:
[0029]
- 10
- shoe sole
- 11
- heel area
- 12
- ball area
- 14
- insole
- 15
- midsole
- 16
- outsole
- 18
- elastic insert
- 20
- window
- 22
- anti-puncture sheet
- 24
- front portion
- 25
- middle portion
- 26
- rear portion
- 28
- hole
- 50
- upper
- 52
- protective cap
1. A shoe sole (10) comprising a heel area (11) and a ball area (12), an insole (14),
an outsole (16) configured to come into contact with the ground, a midsole (15) between
the insole (14) and the outsole (16), an elastic insert (18) embedded into the midsole
(15) in the heel area (11) of the shoe sole (10) and an anti-puncture sheet (22),
characterised in that said anti-puncture sheet (22) has a front portion (24) locating between the insole
(14) and the midsole (15) in the ball area (12) of the shoe sole (10) and a rear portion
(26) locating between the outsole (16) and the elastic insert (18) in the heel area
(11) of the shoe sole (10).
2. The shoe sole according to claim 1, characterised in that, said anti-puncture sheet (22) further comprises a middle portion (25) connecting
the front portion (24) and the rear portion (26), which front portion (24), middle
portion (25) and rear portion (26) are made of same material.
3. The shoe sole according to claim 1 or 2, characterised in that, said anti-puncture sheet (22) is a shaped metal plate, preferably a shaped steel
plate.
4. The shoe sole according to any of the claims 1 to 3, characterised in that, the anti-puncture sheet (22) has an upper surface facing the insole (14) and a lower
surface facing the outsole (16) and the front portion (24) of the anti-puncture sheet
(22) is attached to the insole (14) and the rear portion (26) of the anti-puncture
sheet (22) is attached to the elastic insert (18).
5. The shoe sole according to claim 4, characterised in that, the upper surface of the front portion (24) of the anti-puncture sheet (22) is attached
to the insole (14) by gluing and the upper surface of the rear portion (26) of the
anti-puncture sheet (22) is attached to the elastic insert (18) by gluing.
6. The shoe sole according to any of the claims 1 to 5, characterised in that the midsole (15) is attached to the lower surfaces of the front portion (24) and
the rear portion (26) of the anti-puncture sheet (22).
7. The shoe sole according to any of the claims 1 to 5, characterised in that, the midsole (15) is made of and attached to the anti-puncture sheet (22) by moulded
polyurethane material.
8. The shoe sole according to claim 7, characterised in that, the upper surface and the lower surface of the anti-puncture sheet (22) are covered
with a primer for enhancing the attachment of the midsole to the anti-puncture sheet.
9. The shoe sole according to any of the claims 1 to 8, characterised in that, the insole (14) has hole (28) in the heel area (11) of the shoe sole (10), the hole
(28) exposing a major part of the surface of the elastic insert (18) facing the insole
(14).
10. A safety shoe comprising a shoe sole (10) according to any of the claims 1 to 9 and
an upper (50) attached to the shoe sole (10).
11. A safety shoe according to claim 10, characterised in that the upper (50) comprises a protective cap (52) covering the tip of the ball area
(12) of the shoe sole (10).