SKATE AND SKATE-BLADE

Abstract: A skate for ice-skaing has a skate-blade (2), consisting wholly of ceramic material which may be fibre-reinforced. The hardness and low thermal conductivity of ceramic material gives improved skating performance. Suitable materials are aluminium titanate, aluminium zirconate, zirconia silicon nitride, silicon carbide and sialon.

Description: The invention relates to a skate having a skate-blade and to a skate-blade. In this context a skate is an aid which can be affixed to a person's foot and by which he or she may propel himself or herself on natural or artificial ice as a sporting or leisure activity. Many types of skates are known such as racing skates (for competitive use), touring skates (for leisure trips), ice hockey skates, ice dancing skates etc. In The Netherlands the so-called wooden skate has been known from ancient times. This skate comprises a tempered steel slider or skate-iron (more generally skate-blade) and a support often of beechwood in which the skate-blade is held and on which the foot can be supported when skating. The support is detachably fastened with webbing or straps to the foot which is shod or unshod. Nowadays skates with fixed shoes are commonly used, that is to say a skate in which skate-blade and shoe remain fixed to one another. Racing and touring skates of this type often have tempered steel skate-blades held in a tubular support which is attached to the shoe by means of a pair of skate-­ cups and shoe-plates. In this skate the support, skate-cups and shoe-plates are made from aluminium, steel or titanium. A disadvantage of known skates is that the skate-blade is subject to wear and tear in skating. As a result of this skates become blunt quite quickly and then have to be ground to resharpen them. In US-A-4131288 it is proposed to form the ice-contacting portion of the skate-blade of tungsten carbide. A tungsten carbide component is brazed to a steel portion of the blade. The advantage of tungsten carbide is its hardness, which enables the blade to be used for longer without sharpening. A disadvantage of this skate-blade is the difficulty of achieving a strong and permanent bond between the tungsten carbide and the steel of the blade. This bond has poor resistance to mechanical shocks such as occur during skating. FR-A-2586430 suggests forming a coating of various metal oxides, carbides and nitrides on a skate-­ blade, to reduce wear and reduce the coefficient of friction. The object of the present invention is to provide a skate which becomes blunt less quickly, resulting in the achievement of better performance over a longer time and greater distance and which is durable and is simple to manufacture. The invention consists in that the skate-­ blade consists of a ceramic material pr a fibre-­ reinforced ceramic material. It has been found that it is in fact possible to use a skate blade wholly of such a material without fracture or other difficulty which might arise from the known qualities of ceramic materials. The ceramic material should be chosen from the high-quality dense industrial (engineering) ceramic materials now available. With such blades, it has also been found that, under otherwise equivalent conditions, the skate in accordance with the invention has a lower sliding resistance to skating. This can be explained as follows: when skating, a thin layer of water forms between the sliding surface of the skate-blade of the skate and the ice, as a result of the pressure of the skate on the ice and the dissipated skate-energy. Since ceramic materials have low thermal conductivity, with the skate-blade made from ceramic material in accordance with the invention, the heat-energy developed due to friction cannot be dissipated from the ice-contacting surface so well, which means that more water is formed resulting in lower sliding resistance. In the invention, the skate-blade may consist of a ceramic material, selected from aluminium titanate, aluminium zirconate, sialon, silicon nitride, silicon carbide, zirconia and partially stabilized zirconia. Appropriate combinations of these materials, if available, can also be used. Partially stabilized zirconia is zirconia, to which is added an additive to increase ductility selected from yttrium oxide, magnesium oxide, calcium oxide, oxides of rare earths and combinations of these in a maximum total quantity of up to 8 mol percent. This material is less brittle and is particularly recommended if the type of use and the conditions when skating make it desirable to have a greater ductility for the skate-blade. Skate-blades made from steel tend to distort plastically, thereby becoming permanently crooked. In the invention, the skate-blade may consist of fibre-reinforced industrial ceramic material. In this case the ceramic material, which may be one of those listed above, is reinforced preferably with inorganic fibres, e.g. SiC whiskers, carbon fibres and combinations of these. This material is also not brittle and at the same time light in weight. An advantage of the invention, is that, since the skate-blade consists of one piece of material, it can only distort elastically (according to Hooke's Law) and therefore returns to its original shape after bending. Preferably, in a cross-section perpendicular to the longitudinal direction of the skate-blade, the thickness of the skate-blade increases with the height i.e. as the distance from the ice-contacting surface increases. This embodiment of the skate-­ blade is not so vulnerable to fracture. The skate-­ blade may consist of a plurality of components arranged in the longitudinal direction of the blade one behind the other, either touching each other or not. This embodiment is inexpensive. The skate-blade may project out of an elongate support in the direction perpendicular to the longitudinal direction of the support (downward direction) by a distance not exceeding 10 mm and preferably not exceeding 6 mm. In this way good longitudinal support against bending is obtained for the skate-blade. The skate blade may be detachably held in the skate. The invention extends to a skate-blade consisting of a ceramic material or a fibre-­ reinforced ceramic material. An embodiment of the invention will be described by way of example with reference to the drawing, in which: Figure 1 is a side-view of a skate in accordance with the invention; and Figs. 2A and 2B show cross-sections of preferred embodiments of the skate-blade of a skate in accordance with the invention on the line II-II in Figure 1. The skate 1 in accordance with the invention illustrated in Figure 1 has a skate-blade 2 and is otherwise designed conventionally for racing and touring skating use. The skate-blade 2 is held in a tube-shaped support 3, which is attached to a shoe 6 by means of a pair of skate-cups 4 and shoe-plates 5. The skate-blade 2 is wholly made of industrial ceramic material and projects downwardly out of the support 3 by a distance not exceeding 6 mm. Thus the elongate support 3 is designed to hold a portion of the blade 2 extending over more than half the blade length, which gives the blade support against bending forces. The skate blade 3 may be planar, but figures 2A and 2B show that alternatively the skate-blade may have a thickness increasing in the height direction of the skate-blade, either with flat side surfaces (Figure 2A) or concave side surfaces (Figure 2B). Although the skate illustrated in Figure 1 is otherwise of conventional design, the expert now has the possibility of adding to the skate design many improvements in his choice of materials and shape of the new skate-blade.

Claims: 1. Skate having a skate-blade (2), wherein the skate-blade (2) consists of a ceramic material or a fibre-reinforced ceramic material. 2. Skate in accordance with claim 1, wherein the ceramic material is one of aluminium titanate, aluminium zirconate, sialon, silicon nitride, silicon carbide, zirconia and partially stabilized zirconia or a combination of two or more of these. 3. Skate in accordance with claim 1 or claim 2, wherein the skate-blade (2) consists of fibre-­ reinforced ceramic material. 4. Skate in accordance with claim 3, wherein the ceramic material is reinforced with inorganic fibres which are SiC whiskers, carbon fibres or combination of these. 5. Skate in accordance with any one of the preceding claims, wherein in cross-section perpendicular to the longitudinal direction of the skate-blade, the thickness of the skate-blade (2) increases with increase in distance to the ice-­ contacting surface. 6. Skate in accordance with any one of the preceding claims, wherein the skate-blade consists of a plurality of components arranged in the longitudinal direction of the blade one behind the other. 7. Skate in accordance with any one of the preceding claims having at least one elongate support (3) for the skate-blade, the skate-blade (2) projecting out of the support (3) in the direction perpendicular to the longitudinal direction of the support not more than 10 mm. 8. Skate in accordance with claim 7 wherein the skate blade projects not more than 6 mm out of the support (3) in said direction. 9. A skate in accordance with any one of the preceding claims wherein the skate-blade (2) is detachably mounted on the skate. 10. A skate-blade which consists wholly of a ceramic material or a fibre-reinforced ceramic material.

Inventors: KONIJNENBURG, JAN TEUN VAN, NIERSTRASZ, EMILE FREDERIK, VAN KONIJNENBURG, JAN TEUN DR. IR.
Applicants: HOOGOVENS IND CERAMICS
Application year: 1988
Main classification: A63C1
IPC codes: C04B35, A63C1