US20080127523A1

US20080127523A1 - Outsole for a Cross-Country Ski Boot or Telemark Boot and Cross-Country Ski Boot or Telemark Boot Having Such an Outsole

Info

Publication number: US20080127523A1
Application number: US11/816,099
Authority: US
Inventors: Bernt-Otto Hauglin
Original assignee: Rottefella AS
Current assignee: Rottefella AS
Priority date: 2005-02-11
Filing date: 2005-02-11
Publication date: 2008-06-05
Also published as: EP1845815A1; WO2006085131A1

Abstract

The invention relates to an outsole for a cross-country ski boot or telemark boot, consisting of a rear portion 11, which comprises a shoe heel 13, and a front portion 12, which is of slightly dish-shaped configuration, the outsole 10 being produced so as to be continuously of relatively hard material, especially plastics, and being provided on the tread side, in the region of the front portion 12 and/or in the region of the rear portion 11, with a tread layer 14 of relatively soft, especially rubber-like, material. An improvement of the bending flexibility is obtained in that the thickness d of the front portion 12 which is to be attached to the upper of the boot in a skin-like manner, at least in the region of the metatarsophalangeal zone M is significantly reduced relative to the remaining region of the outsole 10, especially relative to a region 30 adjacent to the metatarsophalangeal zone M which extends towards the rear of the outsole 10 such that the bending elasticity, about an axis substantially transverse to the longitudinal direction of the outsole 10 in the metatarsophalangeal zone M, is at a maximum.

Description

The present invention relates to an outsole for a cross-country ski boot or telemark boot, consisting of a rear portion, which comprises a shoe heel, and a front portion, which is of slightly dish-shaped configuration, the outsole being produced so as to be continuously of relatively hard material, especially plastics, and being provided on the tread side, in the region of the front portion and/or in the region of the rear portion, with a tread layer of relatively soft, especially rubber-like, material. Moreover, the invention relates to a cross-country ski boot or a telemark boot having such an outsole.
Outsoles of such a kind are generally known. For example, they have been manufactured and sold by the Applicant under the Trade Mark “NNN” for years. Those outsoles have, on the tread side, two longitudinal guidance grooves and also transverse grooves which are connected thereto, the longitudinal guidance grooves extending over the entire length of the sole and co-operating with complementary longitudinal guidance ribs on an associated ski-binding plate. At the front end of the sole, on the tread side, there is provided within a recess provided on the tread side a transverse pin for articulated connection to a ski binding, the articulation being such that the shoe heel can be lifted up freely.
The aforementioned longitudinal guidance grooves are formed not only within the tread layer but also within the outsole itself. As a result, the bending elasticity is considerably impaired, especially in the metatarsophalangeal region of the outsole. In order to solve that problem, EP 0 787 440 B1 proposes that the outsole of a sports shoe be produced from two parts, the rear part being of rigid construction and the front part being made from a soft material. A disadvantage of such an arrangement, however, is that the sole cannot be produced so as to be continuously of one and the same material, for example by means of injection-moulding. The cost of sole manufacture is therefore disproportionately high.
To impart good longitudinal flexibility while maintaining sufficient transverse rigidity, EP 0 029 206 A1 proposes a reinforcing sole for footwear made of a base material wherein stiffening means are embedded in said material. To this end, the sole is provided with windows at the foot plantar and arched region each having so-called sleeve-like seats which are formed as ribs bridging the respective window in a transverse direction. Stiffening foils are embedded in said ribs to confer to the sole an improved transverse rigidity. It is evident that such a reinforcing sole is difficult and thus expensive to manufacture.
DE 42 29 039 C2 discloses a different approach to improve the torsional stiffness and the longitudinal elasticity of a cross country shoe. The concept described therein is based on the idea to modify the insole to affect the properties of the shoe. Specifically, the insole is made of two different materials employed for different parts of the insole. As the mechanical impact of the insole on the entire shoe is limited, said solution is dissatisfying.
CH-C-557 154 is mainly concerned with the heel of a cross country shoe which is designed to prevent snow from sticking to the heel.
The object underlying the present invention is to provide an outsole for a cross-country ski boot or telemark boot, which has a relatively high longitudinal bending elasticity while maintaining a good lateral stability (torsional stiffness) and which, moreover, is comparably easy to produce. Moreover, it is an object of the invention to provide a cross-country ski boot and a telemark boot having such an outsole.
Said object is achieved in accordance with the invention with regard to the outsole by the subject matter of claim 1, advantageous constructional details being described in the subordinate claims. With regard to the boots, said object is achieved by the subject matter of claim 19.
The core of the present invention accordingly lies in the fact that the thickness of the front portion, which is to be attached to the upper of the boot in a skin-like manner, at least in the region of the metatarsophalangeal zone is significantly reduced relative to the remaining region of the outsole, especially relative to a region adjacent to the metatarsophalangeal zone which extends towards the rear of the outsole such that the bending elasticity, about an axis substantially transverse to the longitudinal direction of the outsole in the metatarsophalangeal zone, is at a maximum.
This configuration has the advantage that the functions of the sole both in the longitudinal and in the transverse extension are chiefly determined by the properties of the material selected for both the front and rear portion of the sole. Thus, no additional means such as stiffening ribs or inserts are necessary to impart the desired longitudinal flexibility combined with a sufficient lateral stability to the shoe. By reducing the thickness of the front portion in the region of the metatarsophalangeal zone relative to the remaining region of the outsole, especially relative to a region adjacent to the metatarsophalangeal zone which extends towards the rear of the outsole such that the bending elasticity, about an axis substantially transverse to the longitudinal direction of the outsole in the metatarsophalangeal zone, is at a maximum, it is possible to obtain an outsole which, when attached to a shoe, affects to a very small extent the natural flex of the shoe and the foot, even if the material of the outsole is relatively hard. At the same time, the inventive outsole confers a high torsional stability and thus a good support which helps to prevent injuries and improves skiing performance. Moreover, the inventive outsole can be relatively simple produced by injection molding since the outsole can be made from a single material, in particular plastics.
The so-called metatarsophalangeal zone comprises the so-called metatarsophalangeal bending axis. Strictly speaking, the metatarsophalangeal bending axis is not defined by a line but rather by a strip-shaped zone that extends in a direction transverse to the longitudinal direction of the sole and, more specifically, inclined at an angle to the longitudinal direction of the sole from the inside at the front to the outside at the rear.
Preferably, the thickness of the front portion in the region of the metatarsophalangeal zone is from 1 mm to 4 mm, in particular from 2 mm to 3 mm. This thickness range has turned out to be very efficient for most of the materials suitable for the outsole as regards the bending properties of the outsole.
The thickness of the rear portion between the shoe heel provided at the end of the rear portion and the metatarsophalangeal zone can be from 2 mm to 8 mm, in particular from 3 mm to 6 mm. Thereby, a sufficient torsional rigidity can be obtained for most of the materials suitable for the outsole.
According to a preferred embodiment, the thickness of the rear portion of the outsole, continuously increases, starting from the metatarsophalangeal zone, towards the rear of the outsole at least in the direction towards the rear, starting from the metatarsophalangeal bending zone.
The longitudinal extension of the region of the front portion having a significantly reduced thickness can be from 5 cm to 15 cm, in particular from 5 cm to 10 cm which ensures that a sufficient broad region of the front portion has the requisite flexible bending properties.
Preferably, the front portion in the region of the metatarsophalangeal zone forms a bending zone which is defined by at least one, especially 3 to 6 smooth transverse strips which are spaced apart in the longitudinal direction of the outsole and aligned with transverse grooves formed in the tread layer. Thereby, the bending flexibility is not reduced.
The bending zone of the front portion can comprise at least one, especially 2 smooth longitudinal strips which are spaced apart in the transverse direction of the outsole and aligned with longitudinal grooves, especially longitudinal guidance grooves, formed in the tread layer which likewise contributes to the good bending properties.
According to a further preferred embodiment the longitudinal and/or transverse grooves, at least in the front portion of the outsole, are formed substantially only within the tread layer which can be made of a softer material than the material of the front and rear portion. The material of front portion itself is therefore free of any grooves which could affect the elasticity. The grooves in the softer tread layer are not harmful in this respect.
The embodiments according to claims 9 and 10 also correspond to that concept.
The configuration according to claim 11, according to which the transverse grooves are, at least in the front portion, each curved in a backwards direction, increases the stability of the sole, especially the torsional stability, with the flexibility remaining unchanged.
Preferably, the said smooth longitudinal and/or transverse strips limit, at least partly, recesses formed in an upper side of the front portion, wherein the said recesses project on the tread side of the front portion and support cleats formed in the tread layer. Thereby, stable cleats can be formed by molding the tread layer using the recesses which form corresponding projections on the tread side as basis.
More preferably, the height of the cleats decreases in the running direction such that the cleats are adapted to an inclination of the front portion at least in the region of the metatarsophalangeal zone. This embodiment provides a plane lower contact surface of the shoe, even if the front portion is inclined which promotes a stable connection of the shoe, in particular of the cross country shoe, to a ski binding.
The outsole can consist of a plastics material having a modulus of elasticity of between 200 MPa and 250 GPa, especially between 350 MPa and 200 GPa, the modulus of elasticity governing the thickness in the front portion in such a manner that, in percentage terms, the thickness is greater in the case of relatively high elasticity than in the case of relatively low elasticity. This means that the more rigid the sole material, the thinner the basic sole has to be, at least in the metatarsophalangeal region.
The tread layer is either welded, injected or bonded to the outsole on the tread side.
Also worthy of mention is the detailed arrangement in accordance with claim 17, according to which there are integrated into the lateral boundary of the recess at the front end of the sole, for the purpose of accommodating a transverse pin, anchoring elements, especially of metal, which are connected thereto. Those anchoring elements are necessary especially when the transverse pin is to be anchored in the relatively soft tread layer. To accommodate the transverse pin it is, of course, also feasible, in conventional manner, for the recess at the front end of the sole to be bounded by two side cheeks of hard sole material which are integrally joined to the outsole.
The rear portion, especially the heel of the outsole, is preferably of conventional construction, that is to say is provided on the upper's side with material-reducing and weight-reducing recesses.

A preferred embodiment of an outsole according to the invention will be explained hereinbelow in greater detail with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view from below of an outsole formed in accordance with the invention;

FIG. 2 is a plan view of the outsole according to FIG. 1 to an enlarged scale;

FIG. 3 is a longitudinal section through the outsole according to FIGS. 1 and 2, along line III-III in FIG. 2, to a reduced scale; and

FIG. 4 is a perspective view from above of the outsole according to FIG. 1.

FIGS. 1 and 2 each show from below an outsole 10 or running sole for a cross-country ski boot. This outsole 10 consists of a rear portion 11, which comprises a shoe heel 13, and a front portion 12, which is of slightly dish-shaped configuration, that is to say shallow dish-shaped configuration, the outsole 10 being produced so as to be continuously of a relatively hard material, especially plastics, and being provided on the tread side, both in the region of the front portion 12 and in the region of the rear portion 11, with a tread layer 14 of relatively soft, especially rubber-like, material. The tread layer 14 is provided with cleats 14 a to facilitate the walking on snow. Together with the associated outsole portions 11 and 12, the tread layer 14, specifically its cleats 14 a define a predetermined overall sole thickness or sole height “h”, as shown in FIG. 3 in the region of a so-called metatarsophalangeal bending zone “M”. The thickness h can vary for each cleat 14 a.
As can be taken from FIG. 3, the thickness d of the front portion 12 in the region of the metatarsophalangeal zone M is significantly reduced compared to the thickness of the remaining region of the outsole, namely to such an extent that the maximum bending elasticity of the outsole 10 occurs in the region of the metatarsophalangeal zone M, about an axis substantially transverse to the longitudinal direction of the outsole 10 in the metatarsophalangeal zone M. Specifically, the reduction of the thickness d of the front portion 12 in the region of the metatarsophalangeal zone M relative to the region 30 adjacent to the metatarsophalangeal zone M which extends towards the rear of the outsole 10 leads to a configuration of the outsole 10 having a very flexible front portion 12 in the region of the metatarsophalangeal zone M and a rigid or stiff rear portion 11 which confers to the outsole 10 a high lateral stability. The high bending flexibility in the metatarsophalangeal zone M ensures a superior performance of a cross country boot provided with said outsole 10 which, moreover, gives good support to the foot.
An optimum relation between the thicknesses d, d′ varies and depends on the specific material selected for the hard layer (integral front and rear portion 11, 12). Good results can be obtained if the thickness d of the front portion 12 in the region of the metatarsophalangeal zone M is from 1 mm to 4 mm, in particular from 2 mm to 3 mm. The thickness d′ of the rear portion 11 between a heel 13 provided at the end of the rear portion 11 and the metatarsophalangeal zone M can be from 2 mm to 8 mm, in particular from 3 mm to 6 mm. The thickness d of the front portion 12 of the outsole 10 corresponds to at most about 50%, especially—as also shown here—25-30%, of the overall thickness h of the hard and soft material. The thickness of the soft material and hence of the tread layer 14 in the area of the cleats 14 a can be from 3 mm to 7 mm, in particular 4 mm to 6 mm.
The longitudinal extension of the region of the front portion 12 having a reduced thickness d is from 5 cm to 15 cm, in particular from 5 cm to 10 cm which ensures that a sufficient broad strip of the front portion 12 has the requisite flexible bending properties.
It is to be understood, that any other value of thickness d, d′ or longitudinal extension can be selected as new upper or lower boundary of a more restricted range which yields the best results depending for example on geometric factors such as the contour of the sole 10 or on material factors such as the density of the selected material.
As can be best seen in FIG. 4, the front portion 12 in the region of the metatarsophalangeal zone M forms a bending zone 25 which is defined by four smooth transverse strips 22 spaced apart in the longitudinal direction of the outsole 10. Moreover, the said transverse strips 22 are aligned with transverse grooves 16 formed in the tread layer 14, as illustrated in FIGS. 1-3. It is to be understood that the transverse strips 22 form part of the front portion 12 and, thus, have the same thickness d as the front portion 12. The bending zone 25 of the front portion 12 further comprises two smooth longitudinal strips 23 which are spaced apart in the transverse direction of the outsole 10 and are aligned with two longitudinal guidance grooves 15 formed in the tread layer 14 (FIGS. 1-3). Said guidance grooves 15 match with a correspondingly profiled ski binding to guide the cross country boot. It is likewise to be understood that the longitudinal strips 23 form part of the front portion 12 and, thus, have the same thickness d as the front portion 12.
The base at least of the longitudinal guidance grooves 15 in the region of the front sole portion 12 is defined by the relatively hard material of the outsole 10 and, hence, by the longitudinal strips 23 while the base of the transverse grooves 16 is formed of a thin layer of the flexible or relatively soft material of the tread layer 14 which does not affect the flexibility of the hard front portion 12, specifically the flexibility of the transverse strips 22 of the front portion 12. It follows that those grooves 15, 16 are formed substantially only within the tread layer 14 of softer material. This configuration together with the alignment of the transverse strips 22 with the transverse grooves 12 further improves the bending flexibility of the front portion 12 in the region of the metatarsophalangeal zone M and thus of the bending zone 25 insofar as the tread layer 14 does not impair the bending flexibility which is mainly determined by the reduced thickness d and the material properties of the front portion 12.
The longitudinal and transverse grooves 15, 16 are preferably so formed that their depths are approximately the same. The transverse grooves 16, both in the front portion 12 and in the rear portion 11, are each curved in a backwards direction.
As illustrated in FIG. 4, the smooth longitudinal and transverse strips 22, 23 cross each other and thereby limit a plurality of recesses 21 formed in an upper side of the front portion 12. The recesses 21 arranged closer to the edge of the sole 10 are partly limited by the strips 22, 23 and the surrounding material of the front portion 12 which has the substantially the same thickness d as the strips 22, 23. The said recesses 21 form corresponding projections on the tread side of the front portion 12 which serve as basis and support for the cleats 14 a formed in the tread layer 14 (s. FIGS. 1, 2). The cleats 14 a can be of any suitable material having almost any hardness. Preferably, the cleats 14 a (and thus the tread layer 14) are made of a material which is softer than the hard material of the front and rear portion 11, 12 of the outsole 10.
As can be seen very well in FIGS. 1 and 2, the cleats 14 a are arranged in three longitudinal rows and six lateral rows in the front portion 12 as well as three lateral rows in the rear portion 11, thereby limiting and defining the two longitudinal guidance grooves 15 and the plurality of transverse grooves 16 on the bottom of the outsole 10.
FIG. 1 further illustrates that the height of the cleats 14 a of the front portion 12 increases in the running direction such that the cleats 14 a are adapted to an inclination of the front portion 12 at least in the region of the metatarsophalangeal zone M. The bottoms of the cleats 14 a both in the front and rear portions 11, 12 are coplanar and form a plane support surface.
The transition from the front portion 12 in the region of the metatarsophalangeal zone M to the adjacent rear portion 11, and thus from the area of reduced thickness d to the area of increased thickness d′ is continuously formed as shown in FIG. 3. This means that the thickness continuously increases starting from the reduced thickness d of the front portion 12 until the maximum thickness d′ of the rear portion 11, specifically before the heel 13, is reached. From FIG. 3, it can also be taken that the thickness “d” of the front portion 12 of the sole consisting of harder material continuously increases, starting from the metatarsophalangeal zone “M”, both towards the rear and towards the front. As a result, the metaphalangeal bending zone “M” is defined by accordingly dimensioning the thickness d, d′ of the sole 10.
At the front end of the outsole 10 there is formed a further recess 17 which is open towards the tread side, within which recess 17 there is arranged a transverse pin 18 for articulated connection to a ski binding (not shown). The recess 17 is laterally bounded by two lands 19 of hard sole material. Alternatively, it may be bounded by the tread layer 14. In the latter case, it is advantageous for anchoring elements of metal connected to the transverse pin 18 to be integrated into the lateral boundaries of the recess 17.
The outsole consists of a plastics material having a modulus of elasticity as mentioned above. It can be manufactured in simple manner by injection-moulding. The tread layer 14 of soft material is welded, bonded or injected to the harder material on the tread side.
The shoe heel 13 can be of conventional construction, especially as shown in FIG. 3; that is, the heel has material-reducing and weight-reducing recesses 20 on the side of the upper.
It should also be mentioned at this point that the slightly dish-shaped configuration of the front portion 12 of the outsole 10 contributes to an improved rigidity, especially torsional rigidity of the outsole 10. It is possible for the depth of the transverse grooves 16 to be dimensioned so as to correspond to the depth of the longitudinal guidance grooves 15.
All features disclosed in the application documents are claimed as being important to the invention insofar as they are novel on their own or in combination compared with the prior art.

LIST OF REFERENCE NUMERALS

10 outsole
11 rear portion of sole
12 front portion of sole
13 heel
14 tread layer
14 a cleats
15 longitudinal groove
16 transverse groove
17 accommodating recess for the transverse pin
18 transverse pin
19 land for the transverse pin
20 recess in the rear portion
21 recess in the front portion
22 transverse strip
23 longitudinal strip
24 region extending towards the rear of the outsole
25 bending zone

Claims

1. Outsole for a cross-country ski boot or telemark boot, comprising a rear portion, which comprises a heel, and a front portion, which is of slightly dish-shaped configuration, the outsole being produced so as to be formed of relatively hard material and having a tread side, there being provided on the tread side, in the region of the front portion and/or in the region of the rear portion, a tread layer of relatively soft material, the thickness of the front portion, which is to be attached to the upper of the boot in a skin-like manner, at least in the region of the metatarsophalangeal zone is significantly reduced relative to the remaining region of the outsole, especially relative to a region adjacent to the metatarsophalangeal zone which extends towards the rear of the outsole such that the bending elasticity, about an axis substantially transverse to the longitudinal direction of the outsole in the metatarsophalangeal zone, is at a maximum.

2. Outsole according to claim 1, wherein the thickness of the front portion in the region of the metatarsophalangeal zone is from 1 mm to 4 mm.

3. Outsole according to claim 1, wherein a thickness of the rear portion between the heel and the metatarsophalangeal zone is from 2 mm to 8 mm.

4. Outsole according to claim 3, wherein the thickness of the rear portion continuously increases, starting from the metatarsophalangeal zone, towards the rear of the outsole.

5. Outsole according to claim 1, wherein the longitudinal extension of the region of the front portion having a significantly reduced thickness his from 3 cm to 15 cm.

6. Outsole according to claim 1, wherein the front portion in the region of the metatarsophalangeal zone forms a bending zone which is defined by at least one, generally smooth transverse strips which is aligned with transverse grooves formed in the tread layer.

7. Outsole according to claim 6, wherein the bending zone of the front portion comprises at least one generally smooth longitudinal strips which is spaced apart in the transverse direction of the outsole and aligned with longitudinal grooves formed in the tread layer.

8. Outsole according to claim 7, wherein the said longitudinal and/or transverse grooves, at least in the front portion of the outsole, are formed substantially only within the tread layer of softer or more flexible material.

9. Outsole according to claim 8, wherein the base at least of a portion of the longitudinal and/or transverse grooves is limited by the front portion and, if applicable, also the rear portion of the outsole consisting of relatively hard material.

10. Outsole according to claim 7, wherein the longitudinal groove(s) is/are of a depth that corresponds approximately to that of the transverse grooves.

11. Outsole according to claim 6, wherein the transverse grooves, at least in the front portion, are, seen from the running side, each curved in a backwards direction.

12. Outsole according to any of claim 7, wherein the said longitudinal and/or transverse strips limit, at least partly, recesses formed in an upper side of the front portion, wherein the said recesses project on the tread side of the front portion and support cleats formed in the tread layer.

13. Outsole according to claim 12, wherein the height of the cleats decreases in the running direction such that the cleats are adapted to an inclination of the front portion at least in the region of the metatarsophalangeal zoned.

14. Outsole according to claim 1, wherein the outsole is made from a plastics material having a Young's modulus from 200 MPa-250 GPa, the Young's modulus governing the thickness in the front portion in such a manner that, in percentage terms, the thickness is greater in the case of relatively high elasticity than in the case of relatively low elasticity.

15. Outsole according to claim 1, wherein the tread layer is welded, injected or bonded to the outsole on the tread side.

16. Outsole according to claim 1, wherein at the front end of the outsole there is formed an accommodating recess which is open towards the tread side, within which accommodating recess there is arranged at least one transverse pin for articulated connection to a ski binding.

17. Outsole according to claim 16, wherein the accommodating recess is laterally limited by two wall portions in the outsole or by the tread layer of softer material.

18. Outsole according to claim 16, wherein anchoring elements, connected to the transverse pin are integrated into the lateral boundaries of the accommodating recess.

19. Outsole according to any of claim 1, wherein in the rear portion, is provided with material-reducing and weight-reducing recesses on the upper's side.

20. Cross-country ski boot or telemark boot with an outsole, according to claim 1 directly attached to the upper in a skin-like manner.

21. Outsole according to claim 6, comprising a plurality of the transverse strips which are spaced apart in the longitudinal direction of the outsole.

22. Outsole according to claim 7, comprising a plurality of the longitudinal strips which are spaced apart in the transverse direction of the outsole.