The invention relates to an anti-slip device for a shoe and to a method for providing a shoe with an anti-slip device.

Various anti-slip devices for shoes are known. For instance, there are anti-slip devices made of rubber and provided with studs on the market, as well as anti-slip devices made of twisted wire, which can be pulled over a shoe sole. In addition, it is known to arrange fixed studs to the shoe heel, for example.

Patent publication Fl 113005 B describes an anti-slip device for a shoe comprising a frame part that has been fitted to the shoe heel in a fixed manner, a wing part fitted in connection with the frame part, a spike part fitted to the wings and a spring part fitted in connection with the frame part. According to the invention, the spike part has been adapted substantially immovably in relation to the wings.

Patent publication DE 742627 describes an anti-slip device attachable to a shoe heel, which device comprises a two-piece front element to be arranged on the front side of the heel, the parts of which front element have been attached to each other by a screw, as well as two curved metal parts attached in a tumable manner to the front element with pins, which metal parts have been attached to each other on the back side of the heel with a lever clamp which can be opened and closed. The curved metal parts are provided with ice spikes.

Problems of the known anti-slip devices are snow and ice accumulating on the anti-slip devices, for example, and the fact that the anti-slip devices are extremely slippery when walking on a paved surface or on an even concrete surface, for example. Furthermore, anti-slip devices to be arranged under the shoe heel lift up the heel in relation to the rest of the shoe, changing thereby the position of the foot during walking.

An advantage of the detachable anti-slip devices is that they can be removed from shoes when going indoors. However, hands get easily dirty when removing the anti-slip devices. Further, a suitable place, such as a

plastic bag, should be available for storing the anti-slip devices while going to a shop, for example. The problem related to fixed anti-slip devices is especially the above-mentioned slipperiness on paved surfaces.

It is an object of the present invention to solve at least some of the above- mentioned problems. In particular, an object of the invention is to provide an anti-slip device for a shoe, which can easily and cleanly be arranged to be to say in use and out of use, that is to a position where it operates as an anti-slip device, and to a position where it does not operate as an anti- slip device. Furthermore, an object of the invention is to provide an anti- slip device, which yields when stepping on a hard surface, such as stone, so that the anti-slip device is not totally in use nor totally out of use in that situation.

The invention relates to an anti-slip device for a shoe comprising

- a first part which can be attached to a shoe heel,

- a second part, to which at least one protruding part has been arranged, which part can be arranged to a shoe heel, and which part can be arranged by its first end to the first part in an articulated manner with a joint, and by its second end to a third part in an articulated manner with a joint, and

- a third part which can be attached to a shoe heel.

The advantage of the anti-slip device according to the invention is, among other things, that the anti-slip device does not extend underneath the shoe heel, whereby the position of the foot does not change. A further advantage is that the anti-slip device has been arranged so that when stepping on a surface, where the anti-slip device is not to be in use, such as on a stone surface, the protruding parts are lifted to the level of the lower edge of the shoe heel. In this way risk of slipping is avoided. Such stone or the like surfaces may also exist outdoors, and it is possible that also outdoors some surfaces have melted, while others are icy. With the anti-slip device according to the invention, risk of slipping is thus avoided both outdoors and indoors, in case one does not remember to take the anti-slip device out of use. Scratching of these surfaces is further avoided. The anti-slip device according to the invention acts thus like the cat's

claws by going out of use when not needed. On the other hand, when moving away from said surfaces, the protruding parts of the anti-slip device take their actual operating position, due to the tension between the parts.

The first position of the anti-slip device according to the invention means thus the position where the device is in use, that is where the tips of the protruding parts are below the lower surface of the shoe heel. This can also be called as the lower position of the anti-slip device. The second position of the anti-slip device means the position where the device is not in use, that is the tips of the protruding parts are clearly above the lower surface of the shoe heel. Thus, this can also be called as the upper position of the anti-slip device. Whereas, the third position of the anti-slip device means a temporary position between these two positions, where the tips of the protruding parts are substantially at the level of the lower surface of the shoe heel. This can also be called as the middle position.

The first part and the second part and, respectively, the second part and the third part, can be attached to each other in an articulated manner with a mobile rivet or a spring, for example.

According to an embodiment of the invention, the first and/or the third part can each also be provided with at least one protruding part. This way preventing slipping is improved, because protruding parts can be arranged on three sides of the shoe heel.

According to an embodiment of the invention, when the anti-slip device is in its first position preventing slipping, an angle α between the first part and the second part, and respectively, between the second part and the third part, is 120—160°, preferably 125—155°, more preferably 135— 145°. When the angle between the parts is chosen to be like this, the tension between the parts of the anti-slip device is sufficient for the anti- slip device to return to its first position, that is to be in use, when walking on a stone surface, for example, is terminated, and the anti-slip device is again needed.

According to another embodiment of the invention, when the anti-slip device is in its second position where the anti-slip device is out of use, an angle α between the first part and the second part, and respectively,

between the second part and the third part, is over 180°, preferably 185 — 210°.

According to yet another embodiment of the invention, the second part can be attached to a shoe heel by its first and second end with one attachment element arranged through the heel. According to yet another embodiment of the invention, the first part and the third part can be attached to the shoe heel with one attachment element arranged through the heel. The attachment element can be a helical pin, for example, to the ends of which nuts have been arranged. On the other hand, the attachment element can also be a hollow pin, on the interior surface of which threads have been arranged, whereby its ends can be provided with screws, which hold the parts attached to the shoe heel. It is obvious to a person skilled in the art, that the parts can be attached to the shoe heel also by other means, such as with screws, especially in case of a closed heel. Accordingly, a combination of a screw and a nut can be used, for example.

According to an embodiment of the invention means have been arranged to the second part for arranging the anti-slip device to its first and second position. The means can be a design integrated to the second part. For example, a protruding part, which can be bent in a desired form, can be arranged to the upper side of the second part. Preferably, the means is in such an angle, that stepping into a small pothole is not sufficient to change the position of the anti-slip device to go out of use. An advantage of the means is that the anti-slip device can be arranged to be in use and out of use also without using hands, for example by pressing against stairs or by helping with the other foot. This way hands do not get dirty and the anti-slip device can be taken out of use without removing it and separately storing it while going to a shop, for example.

According to an embodiment of the invention the first and the third parts are each provided with one protruding part, and the second part is provided with three protruding parts. Naturally, it is possible to use any number of protruding parts in the second part, for example four or five protruding parts. However, it has been found that a preferable total number of protruding parts is about five, because said number is sufficient to achieve anti-slip effect, but still low enough to avoid slipping on stone surfaces, for example.

The protruding parts may be molded directly into parts forming sharp spike-formed protruding parts or they can be rectangular in their side- view. Accordingly, the protruding parts may be separate hard metal studs, which have been attaced to the first, second and third part.

The anti-slip device according to the invention can be fitted either on new or old shoes, that is they can be fitted at a shoe factory when manufacturing the shoe, or retrofitted by a shoemaker. Typically, the parts for the anti-slip device according to the invention are delivered to the shoemaker in a straight form, whereby upon fitting the anti-slip device the shoemaker bends the second part into the shape of the back end of the shoe heel, that is into a curve, for example.

The anti-slip device according to the invention can be manufactured so that the first and the third parts are standardized, and the second part is manufactured in different lengths for shoes of different sizes. Alternatively, the second part can be provided with several openings and with one longitudinal opening, whereby one part suits shoes of all sizes. When fitting the anti-slip device, the shoemaker or the like bends the second part into the proper form and attaches it to the shoe heel by suitable openings, and to the first and the third part in an articulated manner. After this (or the measurement) the second part can be shortened by cutting off the excess length.

The parts of the anti-slip device according to the invention can be manufactured of any suitable material, typically of metal, such as copper or steel.

The first and the third part of the anti-slip device according to the invention are about 3 cm long, for example, and the second part is 6-10 cm long, for example. The protruding parts of the anti-slip device can be 3 mm high, for example, and the parts can be made of a steel plate having a thickness of 1 mm, for example. The parts can be attached to the shoe heel with a helical pin of 5 mm and screws or nuts of 4 mm. When using a pin provided with an inner thread, screws having a length of 20 mm, for example, can be used for attaching parts thereto.

The invention also relates to a method for providing a shoe with an anti- slip device according to the invention, the method comprising steps of:

- measuring the circumference of a heel,

- bending the second part of the anti-slip device into the shape of the back end of the heel,

- forming openings to the shoe heel for attaching the parts, - attaching the first and the third part to the first end, and respectively, to the second end of the second part in an articulated manner with a joint, and

- attaching the first, second and third part to the shoe heel with attachment elements.

The above-described special characteristics and embodiments of the anti- slip device also relate, when appropriate, to the method according to the invention.

The invention is further described with reference to trie enclosed drawing, in which

Figure 1a shows an anti-slip device for a shoe according to the first embodiment of the invention in its second position in a side view,

Figure 1 b shows an anti-slip device for a shoe according to the first embodiment of the invention in its third position in a side view,

Figure 1c shows an anti-slip device for a shoe according to the first embodiment of the invention in its first position in a side view,

Figure 2 shows an anti-slip device for a shoe according to the first embodiment of the invention in a perspective view,

Figure 3 shows an anti-slip device for a shoe according to the first embodiment of the invention illustrated from above,

Figure 4 shows an anti-slip device for a shoe according to the second embodiment of the invention in a perspective view, and

Figures 5a — 5c show the attachment of the parts of the anti-slip device to a shoe heel according to one preferred embodiment of the invention.

Figure 1a shows an anti-slip device for a shoe according to the first embodiment of the invention in its second position in a side view. The

Figure shows the shoe heel 1 as well as the first part 2 and the second

part 3 of the anti-slip device. The first part 2 has one protruding part 4, and two protruding parts 4 can be seen in the second part 3, the third protruding part is left behind the shoe heel, wherefore it is not shown in the Figure.

The first part 2 has been attached by its first end to the second part 3 in an articulated manner with a joint 5, and the first part 2 and the second part 3 have been attached to the shoe heel 1 by the points 6. The Figure further shows the means 7 for arranging the anti-slip device to its first and second position. In this embodiment, the means 7 is a curved part arranged to the upper edge of the second part 3. For taking the anti-slip device out of use, the part 7 can be arranged at the edge of a stairstep, for example, after which by pressing the foot down, the anti-slip device moves to its second position where it is not in use. In a corresponding manner, for taking the anti-slip device into use, the part 7 can be pressed with the other foot, for example, whereby the anti-slip device is shifted to its first position.

In this Figure, the anti-slip device is in its second position, that is out of use. The angle α between the first and the second part (and, respectively, that between the second and the third part) is about 200°.

Figure 1 b shows the anti-slip device according to the first embodiment of the invention in its third position in a side view. In this Figure, the anti-slip device is in its third position, where the anti-slip device shifts by itself when one moves to walk, for example, on a hard stone surface while having the anti-slip device in use. Thus, the anti-slip device yields somewhat so that the lower edges of the protruding parts 4 rise substantially to the level of the lower edge of the shoe heel. The anti-slip device does not, however, totally go out of use, and when one moves back to walk on snow, for example, the tension in the anti-slip device disappears, and the anti-slip device returns back to its first position.

Figure 1c shows the anti-slip device according to the first embodiment of the invention in its first position in a side view. In the Figure, the anti-slip device is illustrated in its first position, that is in the position, where the anti-slip device is so to say in use. In this position, the angle α between the first part 2 and the second part 3, (and, respectively, that between the second part and the third part) is about 120°.

Figure 2 shows the anti-slip device for a shoe according to the first embodiment of the invention in a perspective view. This Figure shows the second part 3 and the third part 8 of the anti-slip device, and the anti-slip device is in its first position. The Figure also shows a joint 5 with which the second part has been arranged by its second end to the third part in an articulated manner.

Figure 3 shows, in a cross-section, the anti-slip device for a shoe according to the first embodiment of the invention illustrated from above. The Figure shows the first part 2, second part 3, third part 8 as well as the means 7, which, in this embodiment, is an integral part of the second part 3. Furthermore, the Figure shows attachement elements 9, with which, on one hand, the first part 2 and the third part 8 have been attached to each other and to the shoe heel 1 , and, on the other hand, the first and the second end of the second part 3 have been attached to each other and to the shoe heel 1. In this embodiment, the attachement elements 9 are hollow pins provided with an inner thread, and having screws 10 fitted to their ends. The Figure shows that according to a preferred embodiment of the invention, the parts of the anti-slip device have been arranged symmetrically in relation to the longitudinal central line of the shoe sole.

Figure 4 shows the anti-slip device for a shoe according to the second embodiment of the invention in a perspective view. In this embodiment, the protruding parts are hard metal studs 11 , the third part 18 (and, respectively, the first part) having one of them, and the second part 13 having five of them, three of which are shown in the Figure. In addition, the second part 13 has several openings 14, at the location of which the parts can be articulated to each other and attached to the shoe heel.

Figures 5a — 5c show the attachment of the anti-slip device parts to the shoe heel according to one preferred embodiment of the invention. The first part 2 and the second part 3 (as well as the third part, which is not shown in the Figure) of the anti-slip device have been attached to the shoe heel 1 so that when the anti-slip device is in its first position according to Figure 5b, that is in use, or in its second position according to Figure 5a, that is it not in use, the direct distance between the attachment points 6a and 6b is smaller than the distance from the attachment point 6b of the first part 2 to the attachment point 6a of the second part 3 via the joint 5. This also relates to the attachment points

that are on the other side of the shoe, where the third part has been articulated to the second part 3.

In a method according to an embodiment the standard-sized first, second and third parts are used. The size or the width of a shoe heel is measured to find out at what distance from each other the attachment points 6a, 6b are to be arranged.

When chancing the position of the anti-slip device from the first position to the second position, or vice versa, the angle α is changed from less than 180 degrees to over 180 degrees, or vice versa. Thus, the joint 5 has to travel over the line between the attachment points 6a, 6b passing through a position where the angle is 180°.

The joint 5 is not thus typically attached to the shoe heel 1 , but it connects the first and the second part to each other. On the other side of the shoe, respectively, the third and the second part have been connected with the joint.

In this preferred embodiment, some structural part of either the anti-slip device or the shoe heel has to yield. According to one embodiment, the anti-slip device, or, for example, the attachment elements 9 shown in Figure 3, can be formed of a sufficiently flexible material. According to another embodiment, the material of the shoe heel 1 yields in the situation so that the attachment elements 9 in the attachment points 6 can move away from each other so that the joint 5 can be clicked over the line between the attachment points 6a, 6b.

The mechanical tension between the parts is at its greatest in the situation according to Figure 5c, the joint 5 being on the line between the attachment points 6, whereby the angle α is 180° In this situation, some part must have yielded for enabling the attachment points 6a, 6b to move away from each other. The tension is reduced when the angle increases or decreases from 180 degrees.