JP3445803B2 - Sports shoes points - Google Patents

Description

Description: TECHNICAL FIELD The present invention includes a point body made of a plastic material and a ceramic insert, the ceramic insert forming a grounding surface of a point (gripping element), and the point body. The present invention relates to a point for sports shoes, which is embedded in the point body, and is also partially embedded in the point body by a metal sleeve embedded in the point body.

BACKGROUND OF THE INVENTION To take advantage of the extremely high wear resistance of ceramic materials to substantially extend the service life of the point, and also to create a risk of injury, wear-induced sharp edges and cuts. , And in order to avoid protrusions on the point, for example aluminum oxide,
Various proposals have already been made to use ceramic inserts made of silicon carbide, tungsten carbide, etc. for sports shoes. However, to date, on the one hand, it has been found difficult to firmly bond the ceramic insert to the point body so that it can reliably withstand the forces exerted during use of the sports shoe, On the other hand, it has been seen that it is difficult to keep manufacturing costs low because ceramic points are actually more expensive than conventional shaped points.

The known ceramic point (EP 231 797), as mentioned at the beginning of the description, already provides a comparatively favorable stability / production cost ratio. At this point, the outer surface of the ceramic insert, which is gripped by the metal sleeve, is provided with recesses and / or projections, preferably annular ribs and grooves, which inside the metal sleeve are filled with a plastic layer. The protrusions are contained in the plastic layer. In addition, these annular ribs / rings are used to lock the ceramic insert in place.
The annular groove is such that the thicker portion of the plastic layer between the outer peripheral surface of the ceramic insert and the inner surface of the metal sleeve allows the force acting on the ceramic insert during use of the point to be more evenly transmitted to the metal sleeve, and It is transmitted to the point body through the sleeve. However, this known point also did not completely eliminate the risk of local overloading of the connection between the ceramic insert and the point body in the region of the metal sleeve.

Therefore, it is an object of the present invention to configure a ceramic point, such as the one mentioned at the outset of this specification, to have increased stability and strength while having a simple and therefore inexpensive construction.

DISCLOSURE OF THE INVENTION According to the present invention, the above object is achieved in that at least the portion of the outer peripheral surface of the ceramic insert held by the metal sleeve is smooth and narrows toward the ground contact surface.

According to the invention, the ceramic insert does not have any recesses or protrusions on its outer peripheral surface, its outer peripheral surface is substantially very smooth and at least slightly thinner towards the ground plane, During the manufacturing stage, a plastic layer is formed between the outer peripheral surface of the ceramic insert and the inner surface of the metal sleeve, and the thickness of this plastic layer is
The thickness is uniformly thinned toward the end face on the side farther from the ground plane in a manner corresponding to the taper of the ceramic insert. If a lateral load is applied to the ceramic insert, even under high load, the bearing pressure generated in the critical area of the edge of the metal sleeve is the result of the local destruction of the plastic material causing the ceramic to break down. It is transferred to the metal sleeve at that point without wobbling of the insert. Furthermore, the ceramic insert has a very slight tapered shape, and the ceramic insert is
In particular, because it is held inside the metal sleeve in a firm locking relationship, the shape of the ceramic insert is close to a cylinder, and when a load is applied, an effective stress field is generated inside the ceramic insert itself, There is almost no risk of damage. According to a preferred embodiment, the taper angle does not exceed 6 °.
Finally, the costs involved in the production of the ceramic insert according to the invention are at the beginning of the description, especially if the ceramic insert has a continuously smooth and tapered shape up to its ground plane. It is significantly lower than the costs required for the production of the cited ceramic inserts with recesses and protrusions on their outer peripheral surface. Thus, due to its simple shape, this ceramic insert is available in its exact size after the ceramic firing operation. Even if a polishing operation is effective in obtaining a smooth outer peripheral surface, the shallow taper makes it easier to perform.

The metal sleeve and the ceramic insert are dimensionally matched to each other so that the ceramic insert fits within the metal sleeve up to its top plate. As a result of the tapering of the ceramic insert and the desirable inner cylindrical surface of the metal sleeve, there is always an annular gap formed in the edge region of the metal sleeve, which at the time of manufacture of this point is fluid A plastic material having a can pass through the annular gap and enter the interior of the sleeve, forming the plastic layer described above. It should be appreciated that the width of the annular gap depends on the clearance existing between the inner surface of the metal sleeve and the end of the ceramic insert remote from the ground plane. This clearance is only 1mm
It is preferable that the inner surface of the metal sleeve comes into contact with the end of the ceramic insert on the side far from the ground plane and is small enough. In this case, during the manufacturing stage, it is preferable to provide through holes evenly distributed in the wall around the metal sleeve in order to ensure that the ceramic insert is fully embedded in the plastic material of the point body. The plastic material penetrates the inside of the metal sleeve through the through hole, and a plastic layer can be formed to a satisfactory degree even in an area having a small thickness.

In a configuration in which the present invention is effectively developed, the ceramic insert is provided with a recess reaching the outer peripheral surface on the end surface of the ceramic insert remote from the ground contact surface. Since the recess communicates with the outer peripheral surface of the ceramic insert, the recess is filled with a plastic material at the manufacturing stage, and the plastic material securely locks the end face of the ceramic insert to the point body. In the simplest case, the recess may be a straight groove extending across the end face, the ends of which communicate with the outer peripheral surface of the ceramic insert. However, it is also possible for the recess to be cruciform or star-shaped with cruciform or star-shaped arms extending on the outer peripheral surface of the ceramic insert. This similar coupling structure also ensures that the ceramic insert is lock-coupled to the point body with respect to the torque force acting about its longitudinal axis. While the pliers often remove the point from the sole of a sports shoe if the wrench engaging surface of the point body is already worn, the above configuration allows the ceramic insert to withstand such attempts.

The point according to the invention can be removably coupled to the sole of a sports shoe in the usual manner,
Alternatively, it can be directly formed on the sole, and in the latter case, the point body and the sole are made of the same material. In order to carry the vertical load caused by the weight of the athlete in use and to transfer this load to the sole of the sports shoe, if the metal sleeve supports the end face of the ceramic insert remote from the ground plane, and It is advantageous if a top plate is provided for that purpose. In an embodiment of the point with a metal shank protruding out of the point body to releasably secure the point, a metal sleeve is bent over around the flange-like enlargement of the metal shank, And it is desirable that they are welded. In that case, the enlarged portion forms the top plate portion of the metal sleeve. If the point is integral with the sole, the metal sleeve engages its upper edge around the disc forming the top plate,
And preferably joined thereto by crimping or welding.

Ceramic inserts, especially of which a part is gripped by a metal sleeve, usually have a circular cross section, the metal sleeve having a shape adapted to the shape of the ceramic insert. However, the cross-sectional shape of the ceramic insert can basically adopt a cross-sectional shape different from a circular cross-section, such as an elliptical cross-section or an elongated cross-section, provided that a smooth outer peripheral surface is ensured. is there.

Further advantages and features of the invention will be apparent from the following description of embodiments and the appended claims with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross-sectional view of a stud-shaped point.

FIG. 2 is a similar longitudinal sectional view of a point permanently attached to the sole in a dog-like manner.

FIG. 3 is a further similar longitudinal section view of a removable point in the shape of a spike, for example for a golf shoe.

FIG. 4 is a further similar longitudinal cross-sectional view of an elongated form of point permanently attached to the sole in a dog fashion.

  FIG. 5 is a sectional view taken along the line VV of FIG.

  FIG. 6 is a sectional view taken along line VI-VI of FIG.

Preferred Embodiments of the Invention The points shown enlarged in FIGS. 1 to 3 are in their basic part and in their form:
It is not necessary to show the bottom view because it is all rotationally symmetric. However, as described above, the rotationally symmetric shape is not an essential condition of the present invention, and it is possible to change the shape to an elliptical shape or an elongated cross-sectional shape, for example.

The stud bolt type shown in FIG. 1, for example for a football boot, consists essentially of a point body 1, a ceramic insert 2 and a metal sleeve 3.
A metal shaft portion 4 having a thread groove projects from the upper end thereof.

The point body 1 is made of a relatively rigid plastic material, for example polyamide or polyurethane, which is flowable during the manufacturing process and which can be produced using injection moulding. Regarding the form of the point body 1, since it is a normal point, in particular, a type known as an implanting type, further detailed description is not required. This also applies to the fact that the outer shape of the point body 1 is also not important, it may be conical or cylindrical or the like. further,
An engaging surface 11 for a tool or a wrench for turning this point is provided, and the support surface 12 that abuts the ground contact surface of the shoe sole (not shown) has an unfixed point fixed to the shoe sole. A contoured form can be provided to prevent or prevent rotation in the.

The ceramic insert 2 is a shock-resistant ceramic part, and for example, the main component (96%) is aluminum oxide (Al).
₂ O ₃ ), silicon carbide (SiC), silicon nitride, zirconium oxide, steatite or other oxide or non-oxide high performance ceramics. The ceramic insert 2 comprises a ground plane 21 which may be flat or slightly lenticularly curved, the ground plane 21 being
It is connected to the outer peripheral surface 23 via a boundary portion 22 which is rounded in an arc shape. The outer peripheral surface 23 is slightly conical, that is, it tapers toward the contact surface 21, and the taper angle α (or half of the cone angle) is about 1.5 ° in the illustrated embodiment and should not exceed 2 °. Is desirable. A linear groove 25 having a substantially rectangular cross-sectional shape is formed on the upper end surface 24 of the ceramic insert 2 which is located on the side far from the ground contact surface 21 and which also has a rounded edge. Extends across the upper end surface 24 and communicates with the outer peripheral surfaces 23 on both sides. In the illustrated embodiment, the diameter of the ceramic insert 2 is approximately 10 mm at the upper end surface, the length is approximately 11 mm, and the depth of the groove 25 is approximately 1.5 mm.

The metal sleeve 3 is made of steel and covers the upper part of the ceramic insert 2, which corresponds to about 40% of the total length, and engages with the ceramic insert 2. The lower end portion of the metal shaft portion 4 has a shape that forms a flange-shaped enlarged portion 41,
The upper part of the metal sleeve 3 is bent and welded over its edge. This configuration means that the enlarged portion 41 forms a flat top plate portion, and the flat end surface 24 of the ceramic insert 2 is in contact with and directly supported by the top plate portion. The inner surface 31 of the metal sleeve 3 has a substantially cylindrical shape, and its inner diameter is the outer peripheral surface of the ceramic insert 2.
The boundary area with 23 is the inner surface 31 of the upper portion of the metal sleeve 3.
To be abutted almost or completely against. Further, the metal sleeve 3 is provided with six circular through holes 32 which are evenly distributed around the outer circumference thereof, and these holes are
In the space defined by the circular end face 24, and thus in the groove
It has a size that allows plastic material to enter both ends of 25. The lower part 33 of the metal sleeve 3 is stepped by increasing the wall thickness and is thereby strengthened.

As is apparent from FIG. 1, most of the entire length of the ceramic insert 2 together with the metal sleeve 3 is the point body 1.
Embedded in the plastic material, which secures them in a positive locking relationship. In this arrangement, the plastic material of the point body extends into the space existing between the inner surface of the metal sleeve 3 and the outer peripheral surface 23 of the ceramic insert, forming a plastic layer 14 there, which layer: The ceramic insert 2 is supported by the metal sleeve 3 when a load is applied at this point in the radial direction, ie transverse to the longitudinal axis. The thickness of the plastic layer 14 is uniformly thin toward the end face 24 in a manner corresponding to the shape of the space, apart from the connecting portion to the point body 1 through the through hole 32, but the circumference is In terms of direction, the thickness of the plastic layer 14 in the region of increased thickness of the metal sleeve 3 is in each case substantially constant. The edges of the through holes 32 are rounded in a manner not shown in order to minimize shearing effects at the joints of plastic material extending through the through holes 32.

The fact that the upper end surface 24 of the ceramic insert 2 is in direct contact with the top plate portion 41 of the metal shaft portion 4 is due to the fact that no plastic material layer is formed at the portion out of the groove 25 at the manufacturing stage at this point. , Which means that a ceramic-metal contact is formed at that location, so that the vertical load is transferred directly to the metal sleeve 3 or the threaded shank 4. However, it is possible that the end face 24 does not abut the top plate portion 41 uniformly within the inevitable manufacturing tolerances of both the ceramic insert 2 and the metal sleeve 3. Therefore, the plastic material may also enter a portion between the top plate portion 41 and the portion of the end surface 24 that is not in contact with the groove 25. However, as a result, it is desirable that the associated "dead space" be filled with plastic material, which results in uniform force transmission. Furthermore, the impact that occurs is mitigated by the elasticity of the plastic material. If it is desired to emphasize this effect, the end face 24 may be formed in a convex lens shape.

The dog-shaped points shown in FIG. 2 are:
It comprises a point body 1'which is integrally formed with the sole 5 of the same plastic material as the sole 5 of which only a part is shown. This plastic material differs from the plastic material forming the point body shown in FIG. 1 in order to obtain suitable softness and flexibility to satisfy the set requirements regarding the function of the sole. The ceramic insert 2'is identical to the ceramic insert 2 shown in Fig. 1 and therefore does not require a more detailed description. This also applies to the metal sleeve 3 ', which engages on the ceramic insert 2', but
The difference from the embodiment described with reference to FIG. 1 is that the top plate portion 41 'is formed by a flat disc welded or pressure welded to the upper edge of the metal sleeve 3'with the flange. is there.

The embodiment of FIG. 3 has a basic configuration substantially corresponding to that shown in FIG. The present embodiment comprises a point body 1 "made of a relatively hard plastic material, for example polyamide, and having a conical shape. The point body is rotated by a suitable rotating tool or wrench. And an enlarged edge 12 "intended to abut a sole (not shown) at the upper end.

In the present embodiment, the ceramic insert 2 ″ is relatively thin because its intended use is a golf shoe spike, and the diameter is about 3 mm at the upper end and the ground contact surface 21 ″.
The length is 0.6 mm and the length is about 12.5 mm. The conical taper angle α (or half of the cone angle) of the ceramic insert 2 ″ is about 6 °. In the present embodiment, as shown in FIG. As a result, the ground plane 21 ″ is relatively small and acts as a pointed tip.

At its upper end, the metal sleeve 3 ″ is press-fitted into a groove 42 ″ formed in the lower end surface of the metal shaft portion 4 ″ so as to be coupled to the metal shaft portion 4 ″. Therefore, the top plate portion is directly formed by the end surface 41 ″ of the metal shaft portion 4 ″. In the usual manner, the metal shank 4 "is provided with external threads so that it can be screwed into the sole of the golf shoe in a suitable manner. The metal sleeve 3" is circumferentially evenly distributed on its wall. Provided with four through holes 32 ", which are provided at the above-mentioned positions on the end face of the ceramic insert, by which the plastic material that enters the hole during the manufacturing process flows around the upper end of the ceramic insert 2". It extends upward enough to pass through a groove (not shown).

As in the previous embodiments, the metal sleeve 3 "has a cylindrical inner surface 31" and the ceramic insert 2 "has a larger taper, resulting in a plastic layer whose thickness decreases sharply upwards. A 14 "is formed during the manufacturing process between said inner surface 31" and the ceramic insert. Therefore, in the region of the lower edge of the metal sleeve 3 ", the ceramic insert 2" is of a relatively thick plastic layer 14 ". It is supported on the metal sleeve 3 "via the annular part. Due to the slender form and the length of the ceramic insert 2", a relatively high lateral load is exerted on this area, which is Metal sleeve 3 "well dispersed through a thick plastic layer 14"
Transmitted to.

The points shown in FIGS. 4 to 6 are formed as one piece with the sole 105 only partially shown,
It comprises a point body 101 made of the same plastic material as shown in FIG. However, the ceramic insert 102 covered by the point body 101 is
It has an elongated cross-sectional shape with longitudinal side faces that are parallel to each other and are joined together at both ends by an arc. The end surface and the side surface of the ceramic insert 102 are tapered downward, and the taper angle α is about 2 °. contact area
Although 121 is slightly convex, the flat upper end surface 124 is provided with three grooves 125 extending in a direction transverse to the longitudinal axis of the ceramic insert 102 and extending to both side surfaces. As is clear from FIG. 6, these grooves 125 are rounded at the boundary between both side surfaces. In the illustrated embodiment, the ceramic insert 102 has a length at the upper end of about 17 mm, a width of about 4 mm, and a height (corresponding to the length of the embodiment of FIGS. 1-3) of about 8.5 mm. .

This ceramic insert 102 is about 2/3 of its height
Is held by a metal sleeve 103 having an internal space formed in a shape corresponding to the sectional shape of the ceramic insert. The inner surface 131 of the metal sleeve 103 is formed by generatrix lines extending in the vertical direction in parallel with each other. The metal sleeve 103 is integrally formed from steel by, for example, extrusion molding or deep drawing, and has a top plate portion 141 having four circular through holes 142 evenly distributed in the longitudinal direction.
Is equipped with. Further, the metal sleeve 103 is provided with circular through holes 132a on both end faces forming a cylindrical shape, and is provided with three circular through holes 132b evenly distributed on both side faces parallel to each other at the same height. There is. The through hole 142 formed in the top plate portion 141 is a groove of the ceramic insert 102 through which the plastic material passes through the hole 142 during the molding operation of the plastic material.
It is arranged to at least partially overlap the groove 125 so as to enter the inside of the groove 125.

The ceramic insert 102 has its upper end surface 124, which is disengaged from the groove 125, brought into contact with the top plate portion 141 or the hole 142, and is also embedded in the plastic material of the point body 101. Since the plastic material of the point body 101 also enters the inside of the metal sleeve 103, a plastic layer 114 is formed between the inner surface of the metal sleeve 103 and the side surface or the outer peripheral surface of the ceramic insert 102. The thickness of the plastic layer 114 is the same as the through holes 132a,
Apart from the connecting part to the point body 101 through 132b,
The end surface 12 is formed in a manner corresponding to the shape of the internal space of the sleeve.
The thickness in the lower edge region of the metal sleeve 103 is substantially constant in any case in the circumferential direction, though the thickness becomes uniform as it goes to 4.

It is possible to deviate from the embodiments described above in various ways without departing from the object of the invention. That is, the tapered shape of the ceramic insert creates an annular void in the lower edge of the metal sleeve through which the plastic material passes to form the desired plastic layer if the inner surface of the metal sleeve is cylindrical. Therefore, the through hole of the metal sleeve described above is not always necessary. However, it is also not necessary for the inner surface of the metal sleeve to be cylindrical, in other words the metal sleeve may taper upwards or downwards. In that case, the desired plastic layer is formed by appropriate sizing of the metal sleeve and / or by using through holes such that the plastic material can sufficiently fill the ceramic insert during the manufacturing process.

The present invention exclusively uses inserts made of ceramic because it has the property of not forming sharp edges when worn, but the use of inserts made of hard metals or alloys or metal carbides is also relevant. Considered equivalent.

As used herein, the concept of smoothness of the outer peripheral surface of the ceramic insert is independent of the inherent roughness of the ceramic surface, and the outer peripheral surface has protrusions or depressions that significantly determine its size and shape. It means the fact not to. However, since it is preferable that the ceramic insert is inserted without being post-processed on the outer peripheral surface of the ceramic insert as it is at the time of firing, some roughness of the ceramic surface under that condition may not be applied to the outer peripheral surface of the ceramic insert. Adhesion of plastic materials can be promoted.

  The embodiments of the present invention will be described below item by item.

1. Point body made of plastic material (1,1 ′, 1 ″;
101) and a ceramic insert (2,2 ', 2 "; 102), the ceramic insert comprising a ground plane (21,21', 2).
1 ″; 121) and is embedded in the point body, and is also embedded in the point body by a metal sleeve (3,3 ′, 3 ″; 103) Partially gripped, forming a plastic layer (14,14 ', 14 "; 114) between the outer peripheral surface (23,123) of the ceramic insert and the inner surface (31,31"; 131) of the metal sleeve. A point for sports shoes, characterized in that at least a portion of the outer peripheral surface of the ceramic insert held by the metal sleeve is smooth and narrows toward the ground contact surface. .

2. The point for sports shoes according to the first embodiment, wherein the ceramic insert is smooth and continuously tapered toward the ground contact surface.

3. The ceramic insert has a circular cross-sectional shape,
A point for sports shoes according to claim 1 or 2, characterized in that it is conically tapered to have a taper angle (α) of at most 6 °, preferably at most 2 °. .

4. The point for sports shoes according to any one of the first to third embodiments, wherein the inner surface of the metal sleeve is cylindrical, particularly cylindrical.

5. The metal sleeve has an edge facing the ground plane (33)
The point for sports shoes according to any one of the first to fourth aspects, wherein the wall thickness is increased in the above.

6. A point for sports shoes according to embodiment 5, characterized in that the metal sleeve comprises a thickened wall portion starting from the edge of the metal sleeve facing the ground plane.

7. The embodiment according to any one of claims 1 to 6, wherein the metal sleeve is provided with through holes (32, 32 ″; 132a, 132b) in a wall portion of the metal sleeve. Points for sports shoes.

8. The point for sports shoes according to the seventh embodiment, wherein the through holes are evenly distributed around the circumference of the metal sleeve.

9. The sport according to any one of claims 1 to 8, wherein the inner surface of the metal sleeve is in contact with an end of the ceramic insert on a side far from the ground plane. Points for shoes.

10. The embodiment wherein the ceramic insert is provided with at least one recess (25; 125) communicating with the outer peripheral surface on an end face (24; 124) of the ceramic insert remote from the ground plane. The point for sports shoes according to any one of items 1 to 9.

11. The point for sports shoes according to the tenth embodiment, wherein the recess is a linear groove whose both ends communicate with the outer peripheral surface of the ceramic insert.

12. The point for sports shoes according to embodiment 10, wherein the recess has a cruciform shape or a star shape, and the arm thereof communicates with the outer peripheral surface of the ceramic insert.

13. The end face of the ceramic insert on the side far from the ground plane is the top plate portion (41, 41 ′, 4) of the metal sleeve.
Embodiment 1 characterized in that it is in contact with 1 ″; 141)
The point for sports shoes according to any one of items 0 to 12.

14. The point for sports shoes according to embodiment 13, wherein the end surface has a shape that is slightly convexly curved.

15. Metal shafts (4, 4 ') for detachably fixing the point to the sole of the shoe protrude from the point body, and the metal sleeve is fixed to the metal shaft. A point for sports shoes according to any one of aspects 1 to 14.

16. The metal sleeve is bent around the flange-shaped enlarged portion (41, 41 ″) of the metal shaft portion, and the enlarged portion forms a top plate portion of the metal sleeve. A point for sports shoes according to Embodiment 15.

17. The point body is formed of the same material as the sole and is integral with the sole, and the metal sleeve is bent around the edge of the disc forming the top plate of the metal sleeve. The point for sports shoes according to any one of the first to 14th embodiments.

18. The point body is made of the same material as the shoe sole and integrally formed with the shoe sole, and the top plate portion (1) of the metal sleeve (103) is formed.
41) Embodiments characterized in that 41) comprises at least one through hole (142).
Points for sports shoes described in paragraph.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) A43B 1/00-23/30 A43C 1/00-17/06

Claims (8)

(57) [Claims] 1. A point body (1,1 ′, 1 ″; 101) made of a plastic material, and a ceramic insert (2,2 ′, 101).
2 ″; 102), the ceramic insert forming a ground plane (21,21 ′, 21 ″; 121) of the point and embedded in the point body, and also embedded in the point body. Metal sleeves (3,3 ′, 3 ″; 103)
A part of the entire length is gripped inside the point body by the outer peripheral surface (23,123) of the ceramic insert and the inner surface (31,31 ″; 1) of the metal sleeve.
31) In a point for sports shoes having a plastic layer (14, 14 ', 14 "; 114) formed between the same and the outer surface of the ceramic insert, at least a portion held by the metal sleeve is smooth. A point for sports shoes, which is narrower toward the ground contact surface. 2. The point for sports shoes according to claim 1, wherein the ceramic insert is smooth and continuously tapered toward the ground contact surface. 3. A ceramic insert having a circular cross-section and being conically tapered so as to have a taper angle (α) of at most 6 °. Item for sports shoes according to item 2 or item 2. 4. The sport according to claim 1, wherein the inner surface of the metal sleeve is formed by bus bars extending in the vertical direction in parallel with each other. Points for shoes. 5. The sport according to claim 1, wherein the metal sleeve has an increased wall thickness at an edge (33) facing the ground contact surface. Points for shoes. 6. The metal sleeve according to claim 1, wherein a through hole (32, 32 ″; 132a, 132b) is provided in a wall portion of the metal sleeve. Points for sports shoes according to item 1. 7. The invention according to claim 1, wherein the inner surface of the metal sleeve is in contact with an end portion of the ceramic insert on a side far from the ground plane.
The point for sports shoes according to any one of the items. 8. The ceramic insert is provided with at least one recess (25; 125) communicating with the outer peripheral surface on an end face (24; 124) of the ceramic insert remote from the ground plane. The point for sports shoes according to any one of claims 1 to 7.