FR2673362A1 - INTERCHANGEABLE CERAMIC CLAMP. - Google Patents

Abstract

A removable crampon for a team sport shoe, comprising a ceramic support portion intended to come to rest on the ground, a body carrying this ceramic support portion, a provisional attachment part intended for the removable attachment of this body on such a shoe and a maneuvering portion, characterized in that the body and the bearing portion are part of one and the same part made of an entirely ceramic material, based on alumina, which constitutes the main part of the outer surface of the stud.

Description

The invention relates to a crampon for a sports shoe, more

  specifically intended for the exercise of

  mainly team sports such as football or rugby.

  Generally, the crampons are intended to ensure a good grip on the ground during the various movements

that involves the practice of a sport.

  As we know, the manufacturers of sports shoes have been led to develop different ranges of shoes taking into account respectively

  the specifics of various sports.

  These manufacturers have followed a similar diversification approach for the studs with which they equip their various types of shoes. This is how the shape of these studs, their structure, their dimensions, their number and their distribution under the sole of a shoe, depend on the sport in which this shoe, and therefore these

crampons, are dedicated.

  When practicing a sport, the crampons are subjected to significant aggressions which lead to

  wear of these, with possible risks of deformation

  mation especially in case of shock In the case of team sports, such risks of deformation should be minimized as best as possible, to avoid the appearance of sharp edges that could

  lead to injury to other players.

  Taking into account the significant wear phenomenon has led, rather than having to replace the entire shoe, to design interchangeable crampons and, in combination with the concern of minimizing the risks of appearance of sharp edges , led to choosing to make these studs in impact resistant materials while being sufficiently

hard not to wear out too quickly.

  In fact, to minimize the risk of accidents, players should agree to renew their crampons often enough, without waiting for their complete wear or the appearance of sharp edges But for this it would be necessary that these frequent replacements be financially bearable, and therefore that

  interchangeable studs are moderately priced.

  In addition, especially in sports where speed is an asset, crampons, interchangeable or

no, are of low weight.

  Many solutions, adapted more or less specifically to the sports concerned, have already been proposed with a view to achieving one or the other of the abovementioned objectives, but these solutions are not entirely satisfactory.

  because they leave major drawbacks.

  Thus, with regard to the interchangeable crampons at low cost currently known, it should be noted that they are reserved for certain sports (football, rugby) since the concept of interchangeability is only possible for certain forms of crampons, namely cylindrical or cylindrical-conical Their low cost was obtained thanks to the choice of materials suitable for shaping by highly productive means (injection, cold stamping) But the light alloys or plastics used for this reason have the major drawbacks of low resistance mechanical which reduces their longevity The deterioration of the surface condition of the crampons thus manufactured can even be instantaneous when in contact with the ground, thus reducing the safety of these crampons The fixing system which ensures the rigidity of the assembly and the maintenance under the sole is generally made of a resistant material

  (steel) or is oversized (hence problem of standardi-

  These known studs thus have the drawback that the lowering of costs is fictitious because their longevity is very short and their safety is very insufficient. As regards crampons using hard materials, they can be divided into two categories according to whether these hard materials constitute the essential of these crampons (that is to say the essential of the external surface of the protrusions of the sole) or only a part of them In the first case we sometimes speak of massive spikes and in the second case

we are talking about reinforced crampons.

  Massive spikes are described for example in document US-3,522,669 (SIMONS) or in the

  documents FR-2 532 825 and DE-3 233 900 (from SPORTARTIKEL-

  FABRIK KARL UHL Gmb H) These massive crampons are essential-

  actually made of alumina In fact, the document US-

  3,522,669, which dates from 1970, mainly targets golf spikes; these contain at least 85% alumina, the remainder (possibly zero) being formed of components adapted to form a glassy phase intended for the good cohesion of the alumina particles Documents FR-2,532,825 and DE-3,233 900 describe, among other embodiments, studs made entirely of alumina and teach, taking into account the great fragility of this material, to embed these studs of alumina in a frame adapted to absorb the bending forces undergone during

of the practice of a sport.

  It will be noted that the aforementioned massive studs are all permanently anchored in the sole and are not

  therefore not interchangeable removable.

  Reinforced crampons are described in the documents FR-2 532 825 and DE-3 233 900 cited above and in the documents GB-1 277 684 (MUREX), US-3 766 670 (NAKAJIMA), DE-3 915 157 (MORITO) and EP-210-362 (ADIDAS), EP-231 797 (ADIDAS) and DE-3 541 897 (ADIDAS) These studs comprise a body of soft material forming the essential of the lateral external surface of the protuberances of the sole, in which is anchored an insert made of hard material which opens out to the outside of this body only in the end zone of these protuberances intended to form a support zone on the ground: this insert is therefore mainly stressed in compression The constituent material of these inserts are in particular alumina, carbides or cemented metal oxides, tungsten carbide,

  zirconia We also know cermet inserts, that is

  say in a ceramic powder in a metal matrix-

  lique. These inserts sometimes extend deeply

inside the body.

  Except in the case of alumina, the inserts are often heavy (density greater than 6 which can reach 20 in the case of tungsten carbide) which limits them to specific uses such as expensive golf, and crampons in their assembly is complicated and expensive to manufacture The surrounding body is often made of a plastic material, whose properties

  moderate mechanical risks of deterioration

  tion with risks of formation of sharp edges, and which may be unstable when the studs are subjected to severe conditions of use (humidity, shocks, abrasion, temperature), which can endanger

the integrity of the stud.

  It can be noted that the interchangeable removable studs described in these documents are always reinforced studs comprising a hard insert in a

softer body.

  The object of the invention is to overcome the aforementioned drawbacks by proposing an interchangeable removable crampon combining good wear resistance and good shape stability over time (even in the event of impacts), therefore a long service life, while being light and simple to manufacture (therefore capable of being manufactured in

  automated series and therefore of moderate cost).

  The invention thus proposes, a removable crampon for collective sports shoe, comprising a ceramic support portion intended to come to rest on the ground, a body carrying this ceramic support portion, a temporary fixing piece intended for the removable attachment of this body to such a shoe and a maneuvering portion, characterized in that the body and the support portion are part of a single piece made of an entirely ceramic material, based on alumina, which

  constitutes the essential of the external surface of the crampon.

  According to preferred characteristics, the ceramic is an aluminezircone, this alumina-zirconia ceramic contains by volume from 60 to 80% of alumina and from 40 to 20% of zirconia, preferably% to 33% of zirconia, more preferably around 25 % zirconia, the fixing part is fixed by gluing in a housing of the ceramic body,

  the glue is an epoxy glue, preferably monocom-

posing,

  alternatively, the fixing part is fixed by crimping

  wise in a housing of the ceramic body, the cleat being intended for a football boot and generally having the shape of a cylinder, the ceramic body forms the external surface of this cylinder over at least two thirds of its height, the walls of this body have at least 3 mm, the fixing part is a threaded rod, the operating portion is part of this ceramic part, alternatively, the operating portion is independent of the body, the operating portion is integral with the workpiece fixing, the body constitutes the external surface of the crampon on

at least 2/3 of its height.

  Thus, a crampon according to the invention consists of: a ceramic body ensuring most or all of the contact with the ground (support and periphery of the crampon), a fixing piece which can be a threaded rod intended for rapid mounting / dismounting of the crampon on the sole, the fixing piece is made integral with the ceramic body by bonding, soldering, crimping. Such a crampon according to the invention has in particular the advantages: simplification of the shape of the parts and of the manufacturing process , use of ceramic as a structural part, which makes it possible to take advantage of all of its mechanical properties, increase in the ceramic / ground contact area, including around the perimeter of the crampon, therefore reduction of the areas at risk of s '' wear, improvement of the corrosion resistance of the studs, removal or upward displacement of the stud (towards

  the base) of the visible ceramic connection area / -

  rest of the crampon or increased safety.

  Objects, characteristics and advantages of

  the invention will emerge from the description which follows, given

  by way of nonlimiting example, with reference to the appended drawings in which: FIG. 1 is a side view, with partial cutaway, of a crampon according to the invention, and FIG. 2 is a side view, with partial tearing, of another crampon according to the invention. The crampons of FIGS. 1 and 2 respectively marked 1 and 1 ′, comprise a support portion 2 or 2 ′ intended to come to bear on the ground, a portion 3 or 3 ′ forming a body and constituting the essential of the lateral surface of the crampon, and a temporary fixing piece 4 or 4 ', here a threaded rod, intended for the removable fixing of this body to the sole of a shoe (not

shown).

  According to the invention, the portions 2 and 3 (or 2 'and 3') are one and the same ceramic part or in one

ceramic / ceramic composite.

  Opposite the support portion 2 or 2 ', the crampon has an operating portion 5 or 5', here in cross section in the form of a hexagon nut intended to facilitate the assembly / disassembly of the whole of the crampon in a sole Other geometrical shapes are possible (notches) In the example of figure 1, this portion of operation is part of the ceramic body while in the example of figure 2 this portion of operation is a part 6 distinct from this body, from

  preferably secured to the threaded fastening rod 4 '.

  The ceramic having to ensure a rattle of structure, we choose a material with a good

  compromise between hardness / wear resistance / mechanical resistance.

  Preferably, a ceramic / ceramic composite material, alumina zirconia, is chosen, which has the advantage of combining low density, good mechanical strength, good resistance to wear and to

shocks and moderate cost.

  The volume composition of this alumina ceramic is 60 to 80% of alumina and 40 to 20% of zirconia in practice itself stabilized at 2.5 mol% of Yttrium oxide. According to a preferred range, the ceramic contains between 25% and 33% of zirconia and 75% and 67% of alumina Preferably, a composition of 75% of alumina and% of ythriated zirconia is used. The high proportion of alumina allows a moderate cost, while the presence zirconia

  promotes good toughness.

  For a crampon to respond to the invention, it is necessary and sufficient that the ceramic (alumina-based) be the predominant part of the assembly, including its visible external surface, and ensure its structure and rigidity. We can define the ceramic part as the

crampon body.

  In the case considered here for soccer cleats, the ceramic part generally consists of a cylinder of height h and diameter d comprising at one of its ends a flat or slightly curved face forming the bearing surface 2, 2 '' connected to the cylinder generators by radii of curvature r The other end has a housing 8 or 8 'allowing the anchoring of the

fastener head.

  If H is the total height of the crampon visible after fixing under the soleplate, the h / H ratio is at least equal to about 2/3 (Figure 2 o the height of the ceramic piece is noted h) and preferably as close as possible of 1 (Figure 1) In fact it appeared in practice that the risks of damage in the third of the crampon which is close to the sole are acceptable from the safety point of view The difference between h (or h ') and H corresponds in

  practical at the height of the operating part.

  The ceramic volume / fixing part ratio depends on the nature of the ceramic and the

  height of the fastener entering the sole.

  The thickness of the walls is advantageously at least equal to

  3 mm for a 1 or 1 'stud as shown.

  The ratio of ceramic surface to stud surface visible after installation under the base preferably exceeds 0.70 (this is linked to the condition on the

h / h ratio).

  For the connection between fixing piece and ceramic body, all the classic fixing methods can be envisaged but in the spirit of the product two solutions are preferred: bonding with preferential arrangement of longitudinal ribs on the head 7 of the fixing piece entering the housing 8 of the room

  ceramic (see Figure 1), or crimping (see Figure 2).

  For example, the fixing part is made of steel and the assembly with the ceramic body is obtained using a one-component epoxy adhesive sold under the name "PERMABOND ESP 108" When the operating part is separate from the fixing part, it can also be made of steel, or be of a light alloy (aluminum) Many other materials can of course

  be considered, especially plastics.

  It goes without saying that the foregoing description has

  has been proposed as a nonlimiting example and that many variants can be proposed by the man of

  art without departing from the scope of the invention.

Claims (10)

  1 A removable crampon for a collective sports shoe, comprising a ceramic support portion intended to come to rest on the ground, a body carrying this ceramic support portion, a temporary fixing piece intended for the removable fixing of this body sure   such a shoe and a maneuvering portion, charac-   characterized in that the body and the support portion are part of a single piece made of an entirely ceramic material, based on alumina, which constitutes the essential of the outer surface of the stud.   2 Cleat according to claim 1, charac-   terized in that the ceramic is an alumina-zirconia.   3 Cleat according to claim 2, charac-   terized in that this alumina-zirconia ceramic contains, by volume, from 60 to 80% of alumina and from 40 to 20% of zirconia.   4 Cleat according to claim 3, charac-   terized in what it contains, by volume 67% to 75%   alumina and 33% to 25% zirconia.   Crampon according to claim 3, characterized in that it contains, by volume 75% of alumina and % zirconia.   6 Crampon according to any one of the res-   dications 1 to 5, characterized in that the fixing piece   is fixed by gluing in a housing of the ceramic body.   7 Cleat according to claim 6, charac-   terized in that the glue is an epoxy glue.   8 Crampon according to any one of the res-   dications I to 5, characterized in that the fixing part is fixed by crimping in a housing of the ceramic body.   9 Cleat according to any one of the res-   dications 1 to 8, characterized in that, being intended for a football boot and having the shape of a cylinder, the ceramic body forms the outer surface of this cylinder 1 1   over at least two-thirds of its height.   Cleat according to claim 9, charac-   terized in that the walls of this body are at least 3 mm.   11 Crampon according to any one of the res-   dications 1 to 10, characterized in that the piece of fixing is a threaded rod.   12 Cleat according to any one of claims 1 to 11, characterized in that the portion of   operation is part of this ceramic piece. 10 13 Cleat according to any one of claims 1 to 11, characterized in that the portion of   maneuver is independent of the body. 14 Cleat according to claim 13, characterized in that the operating portion is integral of the fixing part.   Crampon according to any one of claims 1 to 14, characterized in that the body   constitutes the external surface of the crampon over at least 2/3 of its height.