US 3798804 A
A safety shoe in accordance with the invention includes a steel protective element in or on a tough plastics shell.
Description (OCR text may contain errors)
United States Patent 1191 Funck Mar. 26, 1974 [5 SAFETY SHOE 3,101,559 8/1963 Smith 36/72 R 3,175,310 3/1965 MacOuaid 36/72 R  Inventor: Herbert Fund, 3,407,518 10/1968 MacQuaid et al. 36/72 R Grafelfing-Lochham, Germany 3.410.007 11/1968 Peterson 36 77 R Assignee:z g Funck Klcq Munich 3,591,532 7/1971 Abercromble et al. 36/2.5 R X Germany FOREIGN PATENTS OR APPLICATIONS  Filed: Jan. 18, 1972 1,006,261 1/1952 France 36 2.5 AL 1,083,787 6/1954 36/2.5 AL 1 PP 218,729 1,304,583 8 1962 France 36/71 722,803 2/1955 Great Britain 36/72 R 1,176,881 1/1970 Great Britain 36 77 R  Apphcat'on Pmmy Data 621,091 5/1961 Italy 36/2.5 AL
Jan. 20, 1971 Germany P 21 02 588.7
52 us. 01. 36/72 R, 36/45 j j jf g' Guest H d F 51 Int. Cl A43b 13/22 gf arson  Field Of Search 36/72 R, 45, 50, 77 R, N we 36/2.5 AL, 7.1 R, 7.3, 2.5 G, 71
 ABSTRACT 56 R f 't 1 e erences Cl ed A safety shoe in accordance with the invention in- UNITED STATES PATENTS cludes a steel protective element in or on a tough plas- 2.229,387 l/l941 Parker 36/72 R X ti h lL 3,067,531 12/1962 Scott et a]. 36/2.5 AL 3,068,593 12/1962 ODonnell 36/72 R 19 Claims, 5 Drawing Figures PATENTEDmzs m4 SHEET 2 (if 3 PATENTED NARZB i974 SHEET 3 OF 3 SAFETY SHOE 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.
1n 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, 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 wearers 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 VV 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 shoe2; 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 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.
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 wearers 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.