U.S. patent number 3,798,804 [Application Number 05/218,729] was granted by the patent office on 1974-03-26 for safety shoe.
This patent grant is currently assigned to Dr.-Ing. Funck K.G.. Invention is credited to Herbert Funck.
United States Patent |
3,798,804 |
Funck |
March 26, 1974 |
SAFETY SHOE
Abstract
A safety shoe in accordance with the invention includes a steel
protective element in or on a tough plastics shell.
Inventors: |
Funck; Herbert
(Grafelfing-Lochham, DT) |
Assignee: |
Dr.-Ing. Funck K.G. (Munich,
DT)
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Family
ID: |
5796426 |
Appl.
No.: |
05/218,729 |
Filed: |
January 18, 1972 |
Foreign Application Priority Data
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Jan 20, 1971 [DT] |
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P 21 02 588.7 |
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Current U.S.
Class: |
36/72R;
36/45 |
Current CPC
Class: |
A43B
7/32 (20130101) |
Current International
Class: |
A43B
7/32 (20060101); A43b 013/22 () |
Field of
Search: |
;36/72R,45,50,77R,2.5AL,7.1R,7.3,2.5G,71 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1,006,261 |
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Jan 1952 |
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FR |
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1,083,787 |
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Jun 1954 |
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FR |
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1,304,583 |
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Aug 1962 |
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FR |
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722,803 |
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Feb 1955 |
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GB |
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1,176,881 |
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Jan 1970 |
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GB |
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621,091 |
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May 1961 |
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IT |
|
Primary Examiner: Guest; Alfred R.
Attorney, Agent or Firm: Finnegan, Henderson, Farabow &
Garret
Claims
I claim:
1. In a safety shoe having built-in protective elements, the
improvement comprising an outer shell terminating at an upper edge
in proximity of the wearer's ankle, said shell having an aperture
providing means for insertion of the wearer's foot into said shoe
and including a tongue opening, a tongue providing means for
closing said tongue opening, said shell including an outer sole and
an upper formed of an integrally molded, continuous, tough,
resilient plastic, which outer shell carries said protective
elements, said outer shell including means for permitting said shoe
to be bent along the bent line under the ball of the foot, which
means comprises slots in opposite sides of the upper of said outer
shell proximate to the sides of the ball of the foot, extending
from the top edge of said outer shell in the direction of said
outer sole.
2. The improved shoe of claim 1 wherein a light inner shoe is
disposed in said outer shell.
3. The improved shoe of claim 2 wherein means for retaining the
shoe on the foot are disposed on said outer shell.
4. The improved shoe of claim 2 wherein the light inner shoe is
made separately from the outer shell.
5. The improved shoe of claim 2 wherein the inner shoe has a light
walking sole.
6. The improved shoe of claim 2 wherein said tongue opening is
closed by a curved plate of hard resilient material which also acts
as metatarsal bone protection, the protective plate being extended
as far as the lateral sole edges to bear thereagainst.
7. The improved shoe of claim 6, wherein the metatarsal bone
protective plate is pivotably mounted on two stub axles extending
laterally from the front cap of the outer shell.
8. The improved shoe of claim 7 wherein the front cap of the outer
shell has a steel cap embedded therein and said steel cap has two
laterally attached stub axles via which the metatarsal bone
protective plate is borne and located.
9. The improved shoe of claim 8 wherein the stub axles each have a
base plate embedded in the outer shell.
10. The improved shoe of claim 1 wherein a suspension device for a
metatarsal bone protection is moulded on to the outer shell.
11. The improved shoe of claim 1, wherein said slots extend from
the top edge of the outer shell to the outer sole.
12. The improved shoe of claim 1 wherein said slots are closed by a
thin flexible skin against the entry of water or dirt.
13. The improved shoe of claim 12 wherein said thin skin closing
said slots is made of the same material as the outer shell, is
unitary therewith, and is curved bellows fashion to permit the
entry of air into said outer shell and to provide means for forcing
air into said shoe when said shoe is bent.
14. The improved shoe of claim 12, wherein the thin flexible skin
closing said slots is made of a resilient, watertight material and
is rigidly connected to the inner surfaces of the outer shell in
the overlapping zones.
15. The improved shoe of claim 1 wherein said tongue is moulded
unitarily on the rear top edge of the front cap of said outer
shell.
16. The improved shoe of claim 1 wherein a metatarsal bone
protective plate is attached to a hinge on the top rear edge of the
front cap of the outer shell, one part of the hinge being unitary
with the outer shell.
17. The improved shoe of claim 1 wherein a steel toe cap and a
steel protective sole are disposed within said molded plastic.
18. The improved shoe of claim 17 wherein a steel cap and a steel
sole are connected to form a unit.
19. The improved shoe of claim 1 wherein said plastic is a
polyurethane foam.
Description
The invention relates to a safety shoe having built-in protective
elements, such as a steel cap, steel plate sole, metatarsal bone
protection and/or heel protective cap.
In the prior art safety shoes of the kind specified the built-in
protective elements have been built into different parts of the
shoe, for instance, the leather uppers, the shoe bottom or the
sole, and connected only when the parts were put together in the
finished shoe. Building the protective elements in this way into as
a rule a number of different parts of the shoe calls for relatively
complicated operations and therefore involves heavy costs.
It is an object of the invention to obviate the complicated
operations of incorporating various safety or protective elements,
thereby reducing the manufacturing costs of the safety shoe.
The basic idea of the invention is to provide all the safety
devices, such as steel cap, steel plate sole and metatarsal bone
protection, in or on a toughly resilient plastics, for instance,
polyurethane foam outer shell, separately form actual shoe
production. At the same time however, the shell carries the means
of attaching the shoe to the foot in the form of conventional laces
or buckles. This basic idea of a novel safety shoe has the
following important advantages for safety shoe manufacture:
Firstly, the complicated incorporation of the steel elements in the
leather shoe is eliminated, and secondly the inner shoe is still
required can be very light, since it no longer has to perform a
supporting function. The use of the very expensive and heavy upper
is therefore completely eliminated. Since also the plastics foam,
for instance the ployurethane foam used for the outer shell, is
very light, having a specific weight of 0.5-0.7 g/cm.sup.3, the
result is a novel shoe which can be made substantially more simply
and cheaply and has unusual novel supporting properties.
A safety shoe according to the invention is therefore mainly
characterised in that the shoe comprises a toughly resilient
plastics outer shell, which is formed by the uppers and outer sole
with heel and can be bent down along the bent line under the ball
of the foot, and a light inner shoe disposed in the outer shell,
the means for retaining the shoe on the foot being disposed on the
outer shell, and the protective elements being disposed in or on
the outer shell.
It is known for ski boots to have usually upwardly hingeable outer
shells of toughly resilient foamed plastics which can receive a
lightweight inner shoe. Auxiliary means for attaching the ski
bindings are disposed on the rigid outer shells, which have very
little flexibility, if any, and which after folding together and
the closure of lever-type buckles firmly enclose the inner shoe and
therefore also are attached tightly to the foot.
Due to their rigidity in the longitudinal direction, which is
advisable for ski-ing, prior art outer shells of the kind specified
are however completely unsuitable as an envelope for safety shoes
whose wearer must be able to walk comfortably and safely in them.
Both the purpose of the outer shell and its technical design are
very different in the safety shoe according to the invention from a
ski boot.
British Pat. Specification No. 1,176,881 discloses a method of
making a working boot of plastomeric material in an injection
operation in which a lining fabric is first fastened to a last and
then a toe-protecting cap and a steel plate sole are attached above
the fabric before the last is inserted into the injection mould.
During the injection operation the plastomeric material encloses
the last with the lining and the protective elements, which remain
in the finished boot after the opening of the mould and removal of
the last from the boot.
Quite apart from the fact that safety shoes must sit firmly on the
foot and "fit" and complete boots made of plastomeric material are
unhealthy, since if they fit tightly the wearer's skin cannot
breathe easily and his foot is inadequately aerated, the usually
steel protective elements bear against the inside of the boot,
often separated from the foot only by a thin lining fabric. As a
result the boots are not only rapidly corroded by sweat but may
also break after corrosion and cause foot injuries.
Working boots of that kind do not suggest the construction of the
safety shoe according to the invention.
As with ski boots, the inner shoe is advantageously given a double
wall. In that case known protective cushionings can be interposed
at all places where it is considered necessary.
Also conveniently the inner shoe, as disclosed in German Pat.
Specification No. 919,088 can have a lightweight walking sole, so
that the inner shoe can be taken out and worn as a house or office
shoe. In that case the inner shoe must have its own tongue and
laces.
Conveniently the outer shell is made in a mould by the injection
moulding process, the safety devices, such as, for instance, the
steel cap and steel sole, being so inserted in the empty mould that
the shell material flows around such parts when the mould is
completely injected; a suspension device can also be used for any
metatarsal bone protection to be moulded on to the outer shell.
There is no difficulty in inserting the steel parts in the outer
shell, since precisely polyurethane foam adheres very
satisfactorily thereto, so that there is no risk that the steel
parts will become detached or move out of place.
A special embodiment of the safety shoe according to the invention
is characterised in that the outer shell, at least in the zone of
the bent line below the ball of the foot, is formed, to increase
its downward bending capacity, with slots extending from the top
end in the direction of the walking sole. This construction ensures
that the shoe, which is of course a working shoe, can bend
downwards satisfactorily in its portion of the ball of the foot,
this being further encouraged by the fact that in the zone of the
bent line below the ball of the foot the bending slots extend from
the edge of the outer shell to the walking sole.
Another particular advantage of the slots is that they aerate the
foot satisfactorily, a feature which is also very important for the
comfortable wearing of the safety shoe according to the invention.
Care must be taken that no water or dirt can get into the shoe
through the bending slots; to this end they are closed by a thin
flexible skin.
An advantageous embodiment of the closure of the bending slots is
characterised in that the thin closure skins of the bending slots
are made of the same material as the outer shell, are manufactured
unitary therewith and are curved after the fashion of bellows.
This feature keeps the foot aerated very satisfactorily, since when
the foot bends downwards the bellows blow like bellows, and suck in
fresh air when released.
In a special embodiment of bending slot closure, selecting closure
materials advantageous to the aeration of the foot, the thin
flexible closure skins are made of a resilient, watertight, but
air-permeable material, such as leather or sail cloth, and the
parts made of such materials, which are inserted in the injection
mould a suitable places before the outer shell is made, are rigidly
connected to the inner surfaces of the outer shells in the
overlapping zones.
A safety shoe according to the invention having a firmly worked-in
inner shoe can very elegantly be made by the outer layer or skin of
the inner shoe forming the flexible closure skins of the bending
slots, the whole inner shoe being pulled over the last of the
injection mould for the outer shell and inserted in the empty
mould, whereafter the inner shoe is rigidly connected to the shell
material during injection.
As a result the bending slots are closed in ideal manner and the
aeration of the foot is very greatly improved by the bellows effect
of the outer skin of the inner shoe. However, the advantages of a
loosely inserted inner shoe must be sacrificed.
Another embodiment of the shoe according to the invention is
characterised in that a tongue-like member is moulded unitary on
the rear top edge of the front cap in the instep zone above the
aperture for slipping in the outer shell.
In some circumstances a separate tongue in the inner shoe can be
dispensed with.
The closure of the slipping-in aperture in the outer shell can also
be combined with the formation of a metatarsal bone protection in a
manner known from U.S. Pat. Specification No. 3,175,292, which
discloses a one-part safety shoe; the closure of the outer shell is
a curved plate of a hard resilient material which also acts as a
metatarsal bone protection. The protective plate, as known from
U.S. Pat. Specification No. 3,068,593, is pulled down to the
lateral sole edge and therefore bears thereagainst.
The metatarsal bone protective plate is connected to the outer
shell, in the manner known from U.S. Pat. Specification No.
3,175,292, in a kind of hinge on the top rear edge of the front cap
of the outer shell, part of the hinge being unitary with the outer
shell.
Another preferred method of connecting the metatarsal bone
protective plate to the outer shell, basically known from U.S. Pat.
Specification No. 3,068,593 is to mount the protective plate
pivotably on two stub axles extending laterally from the front cap
of the outer shell; the stub axles can be inserted in the empty
mould before the outer shell is made.
This kind of connection is suitably made by a very novel form of
the protective steel cap embedded in the front cap of the outer
shell, such novel form being characterised in that it has two
laterally welded or riveted on stub axles which can first be used
for suspending the steel cap in the empty injection mould and then
used for bearing and locating the metatarsal bone protective
plate.
Shoes having a metatarsal bone protection mounted in this way give
very adequate protection against injury to the metatarsus, since
the protective plate is retained against moving out laterally.
In another embodiment, however, the stub axles for retaining the
metatarsal bone protection can each have a base plate embedded by
injection around the material of the outer shell.
The steel cap and steel sole can be very advantageously inserted in
the outer shell if these two members are connected to form one unit
before insertion, as known from British Pat. Specification No.
1,176,881.
An embodiment of the invention is illustrated in the drawings,
wherein:
FIG. 1 is a vertical longitudinal section through the safety shoe
according to the invention;
FIG. 2 is a side elevation of a slightly differently constructed
shoe;
FIG. 3 is a partial plan view of the front zone of the outer shell
of the shoe shown in FIG. 2;
FIG. 4 is a side elevation of a special construction of the shoe
with a metatarsal bone protective plate; and
FIG. 5 is a vertical section, taken along the line V--V in FIG. 4,
the inner shoe being omitted.
The longitudinal section through the safety shoe according to the
invention (FIG. 1) shows a toughly resilient plastics outer shell
1, taking the form of a unitary outer shoe with uppers and sole, a
lightweight inner shoe 2; a steel cap 3 and a steel sole 4 embedded
in the outer shells; insole 5 of the lightweight inner shoe and
walking sole 6 thereof. In this embodiment the inner shoe is
loosely inserted in the outer shell. A piece of material is placed
in the ankle portion of the inner shoe at a place 7 to protect the
ankle. A cushion 7' is worked in between the two layers 2 and 7.
Chain line 8 indicates the course of the outer shell behind the
inner shoe, the lace holes in the outer shell being shown at places
9. The shoe is firmly attached to the foot by a strap (not shown).
The lacing passes over tongue 10 moulded unitary on to the outer
shell. If the inner shoe, having a walking sole, is to be worn
separately from the shell at home or at the office, the inner shoe
must have its own tongue and lacing.
The inner shoe is shown thus constructed in FIG. 2 (lateral
elevation).
FIG. 2 shows eyelets 11 and the inner shoe tongue 12. Unlike the
shoe illustrated in FIG. 1, the safety shoe shown in FIG. 2 has
above its tongue a metatarsal bone protective plate 13 connected to
the outer shell 1 via a tag-shaped attachment 14 moulded unitary on
to the outer shell 1. The metatarsal bone protective plate 13 is
shown in section, to make clear the connection to the outer shell.
The outer shell 1 is formed with bending slots 15 which are
disposed in the zone of the bent line under the ball of the foot
and extend from the top edge of the outer shell to the walking
sole. A non-slip walking section 16 is moulded on to the underside
of the walking sole of the outer shell 1. The bending slots are
closed by a resilient material 17, for instance sail cloth, to seal
off the inside of the shoe from water and dirt. This material
overlaps the slotted apertures as far as the chain line shown in
FIG. 2, so that the material can be connected to the edges of the
bending slots 15.
A plan view of the tip of the outer shell (FIG. 3) shows an
attachment 14 for attaching the metatarsal bone protective plate.
In this embodiment bellows 18 are moulded unitary onto the outer
shell at the edges of the bending slots 15; the highly resilient
bellows substantially seal off the bending slots 15 in the outer
shell 1.
FIG. 4 is a side elevation of the safety shoe according to the
invention with a modifying metatarsal bone protective plate 13'
bearing via its bottom edges against the topside of the laterally
projecting edge of the walking sole of the outer shell 1. The plate
13' therefore completely covers the bending slots 15. In this case
the protective plate is pivotably mounted on two stub axles 19
extending laterally from the steel cap 3 of the outer shell and is
retained by screws 19'. Before the outer shell is made, the inner
shoe 2 is pulled over the last of the injection mould and inserted
together with the last into the empty mould. When the plastics is
injected, the inner shoe becomes intimately connected to the inside
of the outer shell at all places which the plastics touch. In this
case no separate closure is required for the bending slots 15.
In FIG. 5 the inner shoe has been omitted to make the section
clearer. The right hand half of FIG. 5 shows how the stub axle 19
can be welded or connected in any other suitable manner to the
steel cap 3. The metatarsal bone protective plate 13' is pivotably
mounted on free end of the stub axle. This free end was previously
used for suspending the steel cap in the empty mould. The left hand
half of FIG. 5 shows how the stub axle 19 is attached to a base
plate 20 produced in the material of the outer shell 1 by injecting
around when the shell was made. The free end of the stub axle is
again used for the adjustment thereof in the empty mould. In this
case the steel plate sole 4 and the steel cap 3 were welded to form
a unit in known manner.
* * * * *