WO2003028813A2

WO2003028813A2 - Improvements relating to conveyances and particularly to skates

Info

Publication number: WO2003028813A2
Application number: PCT/NZ2002/000203
Authority: WO
Inventors: Andrew John Picard
Original assignee: Andrew John Picard
Priority date: 2001-10-04
Filing date: 2002-10-03
Publication date: 2003-04-10
Also published as: WO2003028813A3

Abstract

A chassis for a clap-skate or a similar device has upper (1) and lower sub-chassis (2). The forward end of the upper sub-chassis (1) is pivotally attached to the lower sub-chassis (2). The upper sub-chassis (1) pivots upward against an adjustable restoring force provided by an easily replaceable leaf spring (15). A roller skate axle pin (40) for use with rollers on in-line roller skates has an axial through hole (41) providing a reduction in overall skate weight. The axle pin (40) may have a threaded end (43) and an axial through hole (41) of non-circular transverse cross-section, eg hexagonal, which allows a correspondingly shaped key to be used when fastening the pin (40) to a skate chassis.

Description

IMPROVEMENTS RELATING TO CONVEYANCES AND PARTICULARLY TO SKATES

FIELD OF THE INVENTION

This invention relates to personal stand-on conveyances to which a user's foot is attached, for example by a boot, shoe, strapping or binding. The invention is particularly related to conveyances, for example skates, skis, snow boards, surfboards, wave boards, wind surfing boards, etc, providing a foot tilting action whereby a user's heel may lift and the foot tilt forward while the conveyance generally remains in contact with the surface over which it is moving. One application is the so called "clap skate" which is used particularly for speed skating either on ice skates or on in-line roller skates, sometimes called "skeelers". The invention also relates to axles for skates incorporating wheels or rollers mounted to rotate about the axles.

BACKGROUND TO THE INVENTION

Clap skates have particular application to speed skating where performance is enhanced by the ability to pivot the foot while maintaining good ground contact allowing longer more powerful strides to be taken. Clap skates are used in both ice and roller skating. A clap skate has an upper chassis, to which a boot or shoe may be fixed, and a lower chassis bearing a blade or at least two rollers. The forward portion of the upper chassis is pivotally mounted to the lower chassis for rotation about a pivot axis which is transverse to the longitudinal axis of the skate. The boot and foot are able to pivot upward and tilt forward with .respect to the blade or rollers, allowing the heel of the skater using a clap skate to be raised and lowered while the length of the blade or the set of rollers remains in contact with the skating surface.

The tilting movement acts against a spring which returns the boot and upper chassis to a normal position relative to the lower chassis when the tilting force applied by the skater ceases, such as when the skate is lifted off the skating surface at the end of a stride. The clap skate is so called because the reinstatement of the normal skate configuration is accompanied by a 'clap' sound as the rearward portion of the upper chassis re-engages with the lower chassis.

European Patent Application 0 192 312 describes an ice skate for speed skating, the skate having a shoe which is forwardly tiltable about a transverse axis against the bias of a coil spring.

United States Patent No. 5, 135, 244 describes a roller skate with a shoe support mounted on a central transverse elastomeric bushing allowing limited forward and rearward tilting movement of the shoe support against spring action provided by the elastomeric bushing. An elongated leaf spring is mounted on the underside of the shoe support to engage front or rear wheels when the support tilts forwards or backwards.

United States Patent No. 5,979,916 describes an in-line roller skate with an upper chassis mounted with an adjustable mclination to a lower chassis. A coil, compression spring supports upper chassis.

United States Patent No. 6,007,075 discloses ice and roller speed skates of the clap skate type having coil and torsion return springs and particularly a coiled extension spring working via a cable routed around a pulley.

United States Patent Nos. 6,079,717 and 6,193,243 disclose both ice skates and in-line roller skates of the clap skate type having a boot support upwardly tiltable against a bias force provided by a coiled torsion spring.

United States Patent No. 6, 113, 111 discloses a frame for skis and roller or ice skates, the frame having an upper sub-frame to which a shoe may be coupled. The upper sub-frame is pivotably coupled to a lower sub-frame which is adapted to be provided with a runner or wheels. A resetting spring, of the helical torsion type, urges the sub-frames toward one another. United States patent No. 6,152, 458 discloses an ice skate for speed skating. A boot is carried on an upper half frame. A lower half frame is fitted with a blade. The upper and lower half-frames are articulated to provide upward and forward movement of the heel region of the boot while the toe region moves backward against a resisting force provided by a cylindrical helical elongation spring.

Known clap skate spring arrangements have not been reliable and have not provided for easy replacement of the spring or springs. Nor have known arrangements provided for simple adjustment of the spring rate, for example to suit the level of skill or ability of the skater or different skating conditions. Furthermore, the location of some spring systems has exposed the springs to damage from contact with obstacles or other skaters. The spring systems in some sprung skates have required an excessive height in the skate to accommodate the spring system.

Excessive weight of skates can reduce the performance of skaters. A reduction of weight in the wheels or rollers or their mounting arrangements is particularly desirable because the reduction in overall weight of a skate is multiplied by the number of wheels or rollers used.

SUMMARY OF INVENTION

An object of one invention described is to provide a clap skate with an effective, reliable and easily replaceable spring arrangement, or at least to provide the public with a useful choice.

An object of another invention described is to reduce the weight of a roller skate.

In a first aspect the present invention may be said to consist in a chassis for a personal stand-on conveyance for supporting a person when traversing over a surface, the chassis having a longitudinal axis and comprising: an upper sub-chassis having first attachment means by which a boot or other foot- supporting means can be attached to the upper sub-chassis, and a lower sub-chassis having second attachment means by which a surface-engaging means for engaging the surface can be attached to the lower sub-chassis, • the upper sub-chassis being pivotably mounted at a forward portion thereof to the lower sub-chassis for relative rotation, about a transverse axis, against a biasing force provided by a spring means, the spring means comprising a length of resilient material which is attached to or bears against the upper sub-chassis at a first location and bears against the lower sub- chassis at a second location, the relative rotation of the upper and lower sub-chassis flexing the spring means between the first and second locations.

Preferably one side of the spring means bears against the upper sub-chassis at the first location and against the lower sub-chassis at the second location, and an opposite side of the spring means bears against the upper sub-chassis at a third location intermediate the first and second locations.

Preferably the side edges of the front end of the leaf spring lie between and engage respective side walls of the upper sub-chassis at the first and third locations and the side edges of the rear end of the leaf spring lie between and engage respective rear mounting flanges to restrain transverse movement of the upper sub-chassis relative to the lower sub- chassis when the upper sub-chassis is pivoted away from the lower sub-chassis.

Preferably the spring means is fixed to the upper sub-chassis at the first location.

Preferably the spring means is a leaf spring which when relaxed is substantially flat.

Preferably the surface is a ground or floor surface, the conveyance is a roller skate and the surface-engaging means is a set of at least two rollers.

Preferably the roller skate is an in-line roller skate. Alternatively the surface is an ice surface, the conveyance is an ice skate and the surface- engaging-means is a runner or blade.

Alternatively the surface is an ice or snow surface, the conveyance is a ski or snow board and the surface-engaging-means is a ski or board.

Alternatively the surface is a water surface, the conveyance is a ski, surfboard or wave board and the surface-engaging-means is a ski or board.

In a second aspect the present invention may be said to consist in a skate comprising: a chassis according to the first aspect, the boot or other foot-supporting means being attached by the first attachment means to the upper sub-chassis, and the surface-engaging means being attached by the second attachment means to the lower sub-chassis.

In a third aspect the present invention may be said to consist in a roller skate axle pin for rotatably supporting a roller in an in-line roller skate, the pin having an axial through hole.

Preferably the axial through hole has a non-circular transverse cross-section.

Preferably the through hole has a hexagonal transverse cross-section.

Preferably the pin is manufactured from a length of material extruded with the non-circular axial through hole, the outside diameter of the extruded material being reduced over a part of the length of the pin to leave a head at one end, and a screw thread.being provided at the other end.

The invention may further be said to consist in any alternative combination of parts or features or steps here mentioned, or shown in the accompanying drawings. Known equivalents of these parts or features or steps which are not expressly set out are nevertheless deemed to be included. BRIEF LIST OF FIGURES

Preferred embodiments of the invention will be described with reference to the drawings 5 of which:

Figure 1 is a side elevation (seen from the left side) of an in-line roller skate chassis, Figure 2 is a plan view of the in-line roller skate chassis of Figure 1, Figure 3 shows a side view (seen from the left side) of a cross-section of the roller skate chassis of Figures 1 and 2 taken at the longitudinal centreline A-A as shown in 10 Figure 2,

Figure 4 is a perspective view of a roller axle pin, and

Figure 5 shows a longitudinal cross-section of the roller axle pin of Figure 4.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS.

15

Referring to the drawings it will be appreciated that the invention, and embodiments incorporating the invention, may be implemented in various forms. Many details will be understood by a skilled reader and have been omitted. The following embodiments are given by way of example only.

20

The following description of skates, and spring biasing arrangements for clap skates, are directed to a preferred embodiment of an in-line roller skate but apply correspondingly to other forms of roller skates, to ice skates and to other personal stand-on conveyances as indicated herein.

25.

Figures 1, 2 and 3 show a chassis for an in-line roller clap skate chassis in side elevation, plan and cross-sectional views. The chassis has two major parts: an upper sub-chassis 1 and a lower sub-chassis 2.

30 The lower sub-chassis is elongate and is equipped with five in-line rollers 3, shown in Figures 1 and 2 by broken lines. The lower sub-chassis has two side walls 4 joined at their upper edges by a transverse wall 5. In one preferred embodiment shown in Figures 1, 2 and 3, the three walls are rounded in transverse cross-section to form a continuously curved U- shaped transverse cross-section as may be best appreciated in the exposed bevelled front and rear ends of the lower sub-chassis as seen in Figure 2. Transverse axle pins 6 for supporting the rollers 3 are mounted between enlargements 7 on respective side skirts 8 at the lower edges of the side walls 4.

The lower sub-chassis carries front and rear pairs of longitudinally-aligned upwardly- extending flanges 10, 11 for supporting the upper sub-chassis as will be explained in more detail below.

The lower sub-chassis 2 may be manufactured from an extrusion, for example of aluminium or an aluminium or duraluminium alloy, the extrusion incorporating the rounded upper and side walls 4, 5, the lower side skirts 8 and the flanges 10, 11. Material is removed from the bare extrusion to form the required shapes, for example, the mounting enlargements 7 for the roller axle pins 6, the front and rear flanges 10, 11, and clearance apertures (not shown) in the upper wall 5 of the lower sub-chassis as may be necessary to accommodate the topsides of the rollers 3. Material may also be removed to lower the weight of the lower sub-chassis, eg by forming thin-wall areas or apertures in the lower sub-chassis.

The front flanges 10 each have three holes 12, seen in Figure 3 and shown by broken lines in Figure 1, which provide three pairs of transversely aligned holes for carrying a pair of co-aligned pivot pins 13 on which the upper sub-chassis 1 pivots. The three pairs of holes

12 are spaced apart in the longitudinal direction to allow the fore and aft position of the pivot axis to be selected. The pivot axis is behind the axis of the front roller and, in the five roller skate, generally over the second roller.

,The rear flanges 11 each have three holes 14 to provide three pairs of transversely aligned holes for carrying a transverse pin 18, shown in Figure 3, which engages the tail end of a . biasing spring 15 as will be explained in more detail below. The three pairs of holes 14 are spaced apart in the longitudinal direction to allow the fore and aft position of the spring- engaging pin 18 to be selected. The outer ends of the holes 14 in the rear flanges 11 are countersunk. The spring-engaging pin 18 has threaded bores at each end and is fixed between the rear flanges by a pair of countersunk head screws 16, one of which is seen in Figure 1. The screws 16 are screwed through the countersunk holes and into the threaded bores of the spring-engaging pin 18. Because they are countersunk, the heads of the pin mounting screws 16 do not impede movement of the side walls of the rear end of the upper sub-chassis, or an associated plastics insert 17 (described below), over the rear flanges 11 when the upper sub-chassis returns to its rest position (best seen in Figures 1 and 3).

The upper sub-chassis 1 is elongate and has two side walls 20 with respective transversely- aligned pivot holes at their front ends. The side walls are joined by a front web 21, just behind the pivot holes, and by a rear web 22, at the rear end of the side walls. The front and rear webs each have a set of three apertures 23, 24 to which the toe and heel of a boot or shoe (not shown) may be attached, either directly or using interposed mounting blocks (not shown). The three apertures of each set are spaced apart in the longitudinal direction of the chassis to allow a range of boot or shoe sizes to be accommodated and/or to allow selection of the fore and aft mounting position of the boot or shoe on the upper skate sub-chassis.

When the upper sub-chassis 1 is in the lowered position (shown by solid lines in Figure 1 and in Figure 3), the upper surfaces of the front and rear webs 21, 22 are substantially horizontal but vertically offset, with the rear web 22 somewhat higher than the front web 21, as may be best seen in Figures 1 and 3. This offset accommodates a usual boot or shoe configuration in which the heel portion is positioned higher than the toe portion.

In an alternative arrangement, not shown, the upper sub-chassis is manufactured from a substantially straight length of material, for example an extrusion made from aluminium or an aluminium or duraluminium alloy, and the front and rear webs are co-planar. The offset in heel and toe height can be provided by sloping the upper sub-chassis or by the use of mounting blocks interposed between the upper sub-chassis and the boot or shoe. The interposed blocks are given different heights or, if mounted on a normally sloping upper sub-chassis, non-parallel upper and lower surfaces. The bare extrusion provides the basic shape of the sidewalls and joining webs. Material is removed from the bare extrusion to form the required shape including the web apertures and to lower the weight of the upper sub-chassis.

In the embodiment shown in Figures 1 and 2, the upper sub-chassis 1 is pivotably mounted at its forward end to the lower sub-chassis 2. The pivot holes at the front ends of the side walls of the upper sub-chassis are carried by bushes, not shown, mounted on respective pivot pins 13 screwed into one of the pairs of transversely-aligned holes 12 in the front pair of flanges 10 of the lower sub-chassis 2.

In the vicinity of the front and rear webs, the upper sub-chassis has an inverted shallow U- shaped transverse cross-section provided by the side walls 20 in conjunction with the front and rear webs 21, 22. The U-shaped cross-section of the rear end of the upper sub-chassis fits over the rear flanges 11 of the lower sub-chassis 2.

An insert 17, preferably made from a plastics material, is fitted on the underside of the rear web and has an inverted shallow U-shaped transverse cross-section. The insert is retained in place by a fastener or fasteners (not shown) fitted through one or more of the apertures 24 to secure the heel of the boot or shoe, or the interposing heel mounting block, to the rear end of the upper sub-chassis. The insert 17 has three apertures which are dimensioned and located to match the apertures 24 in the rear web 22.

The inside lower edges 25 of the insert 17, shown in Figure 3, are radiused or chamfered to facilitate the transverse alignment of the upper and lower sub-chassis when their rear ends close together, for example at the end of a skater's stride. The insert, being made from a softer material than that of the lower sub-chassis, reduces wear of the upper and lower sub-chassis that would, without the insert, otherwise occur at their points of re-engagement. The insert is easily replaced if it becomes damaged or worn.

A flat leaf spring 15 is attached to the upper sub-chassis 1 at the underside of the rear end of the front web 21. In the embodiment shown in Figures 1 to 3, the leaf spring is provided with a central aperture at its front end to accommodate a screw fastener 27 (seen in Figures 2 and 3) which is screwed into a threaded aperture at the rear end of the front web.

In an alternative spring attachment arrangement, not shown in the Figures, a clamping block is fastened to the underside of the rear end of the front web of the upper sub-chassis by a threaded screw fastener. The forward end of the leaf spring is clamped between the clamping block and the underside of the front web to retain the leaf spring in the position shown in Figures 1 to 3. In this alternative mounting arrangement, the leaf spring is not required to have an aperture.

The leaf spring extends rearwardly and is fitted under the transverse pin 18, shown in Figure 3, which is carried by one of the pairs of transversely-aligned holes 14 in the rear pair of flanges 11 on the lower sub-chassis. The leaf spring is slightly flexed to bear upwardly against the transverse pin 18 when the upper sub-chassis is in its lower-most rest position as shown in Figure 3 and in full lines in Figure 1.

The leaf spring 15 may be easily replaced, for example if worn or broken or by a spring having a different spring rate and chosen to enhance skating performance given prevailing or expected race conditions. To replace the spring, the transverse pin 18 is removed from between the rear flanges 11. Although the rear end of the upper sub-chassis may need to lifted slightly to clear the countersunk head screw 16 securing the pin, this requires only a small force. Once the pin has been removed, the upper sub-chassis 1 may be freely pivoted about the pivot pins 13 and tilted up and away from the lower sub-chassis 2. When the upper sub-chassis is tilted up at about 90° to the lower sub-chassis, or beyond, the head of the screw fastener 27 at the front end of the leaf spring (or the threaded screw fastener holding the clamping block in the alternative arrangement discussed above) is accessible and the screw fastener may be unscrewed to release the spring 15. A replacement spring can be fitted by a reversal of the procedure. In the case of the alternative spring attachment arrangement discussed above, the screw fastener need not be totally removed. It need only be unscrewed sufficiently to release the clamping pressure on the forward end of the leaf spring so that the leaf spring can be removed and a replacement spring inserted. The leaf spring 15 is preferably manufactured from a resin, for example a polyester resin, reinforced with glass or carbon fibres. A particularly suitable leaf spring material is a resin, reinforced by longitudinally arranged glass or carbon fibres, and produced by the so-called pultrusion process. Suitable leaf spring materials include spring steels, or resins such as polyester, vinylester, epoxy or polyurethane, the resins preferably being reinforced by glass or carbon fibres.

In use of a skate fitted with the chassis, the upper sub-chassis 1 pivots upward about pivot pins 13 and tilts forward, for example when the skater is . lifting the heel while still maintaining downward pressure on the toe such as when the skate is extended rearwardly from the skater at the end of a stride. This tilted orientation of the upper sub-chassis 1' is shown by broken lines in Figure 1. In this configuration, the front end of the spring 15, being attached to the upper sub-chassis, also tilts upward. However, upward movement of the tail end of the spring is resisted by the pin 18 carried by the rear pair of flanges 11 on the lower sub-chassis. The pin 18 exerts a downward force on the tail end of the spring to flex the spring, shown by broken lines as flexed spring 15' in Figure 1, and thus apply a downward force to the upper sub-chassis which tends to return the two sub-chassis to their normal rest configuration as shown in Figure 3 and by full lines in Figure 1.

To reheve stresses on the screw fastener 27 and on the forward end of the spring 15, ie in the vicinity of the aperture through the spring, (or correspondingly on the clamping block and fastener in the alternative arrangement, not shown), the upper sub-chassis of the preferable embodiment shown is provided with an intermediate transverse web 30, as shown in Figure 3. The intermediate web 30 extends between the side walls 20 of the upper sub-chassis 1 a short distance behind the front web 21. The intermediate web 30 takes the downward force exerted by the leaf spring 15. The screw 27 (or the clamping block and fastener in the alternative arrangement) is thus relieved of the downward force and primarily acts to maintain the spring in position. As a result of the incorporation of the intermediate web, the spring exerts a generally upward force against the underside of the front web in the vicinity of the spring attachment screw or clamping block. However, the combined moment of forces exerted by the spring on the front and intermediate webs acts as a returning force to restore the upper sub-chassis to the rest position. The intermediate web 30 may be integral with the upper sub-chassis as shown in Figures 1 to 3, eg formed by machining away material from a rough extrusion of the sub-chassis to leave the web, or it may be provided as a separate part (not shown) and attached to the side walls 20 of the upper sub-chassis, eg by a pair of threaded screw fasteners at respective ends of the web 30.

As best seen in the plan view of Figure 2, the side walls 20 of the upper sub-chassis are thicker in the vicinity 28 of the front end of the leaf spring 15 so that the distance between the side walls 20 closely matches the width of the leaf spring. The side edges of the forward end of the leaf spring closely engage the inside surfaces of the thickened side walls of the upper sub-chassis.

Similarly, the distance between the rear flanges 1 lclosely matches the width of the tail end of the leaf spring 15 so that the side edges of the tail end of the leaf spring closely engage the inside surfaces of the rear flanges.

These close engagements between the side edges of the front and tail ends of the spring and the upper and lower sub-chassis combine with the rigidity of the leaf spring in its transverse direction to help maintain the transverse alignment of the rearward ends of the upper and lower sub-chassis when they are pivoted apart. The transverse rigidity of the leaf spring thus helps resist transverse twisting forces between the upper and lower sub-chassis which otherwise could only be constrained through the pivot pins 13.

The force biasing the upper sub-chassis to its normal rest position as provided by the leaf spring 15 can be adjusted by selecting the material or dimensions of the spring itself, or by selection of the pair of holes 14 in which the transverse pin 18 is carried. The effect of the latter adjustment is of course also affected by the position of the pivot axis provided by pivot pins 13.

The leaf spring arrangement has been discussed in relation to one preferred application, an in-line roller clap skate. However, it is contemplated that it will be similarly applicable for use on other skates, such as ice skates, or on other similar devices attached to the feet of a user. Examples of such other devices include snow skis, water skis, snowboards, wave boards, surfboards, windsurfing boards, and any other device where a foot of a user may ' be attached to the device but flexing or tilting of the foot relative to the device, and particularly by raising the heel and tilting the foot forward, is desirable.

Figures 4 and 5 show detail of a roller axle pin 40 for supporting the rollers of an in-line roller skate. The pin 40 has an axial through hole 41, preferably of non-circular cross- section, an enlarged head 42 at one end and a threaded portion 43 at the other end. The cross-section of the axial through hole is preferably shaped to accommodate a key of complementary shape by which the pin can be firmly screwed, for example into a threaded aperture on the side skirt 8 of the lower sub-chassis 2, as best seen in Figures 1 and 3.

In one embodiment the through hole 41 has a hexagonal cross-section, as shown in Figures 4 and 5, to match a standard hexagonal wrench or key. Through holes of other non-circular cross-sectional shapes, and corresponding keys, are also contemplated.

The pin 40 can be machined from a length of extruded material, eg aluminium, or an aluminium or duraluminium alloy, with the through hole 41 being formed as part of the extrusion process. After extrusion, the diameter of an intermediate part 44 of the length of the pin is machined down to a reduced diameter to leave an enlarged head at one end. The head preferably has a tapered underside 45 so that it can be countersunk, for example into a side skirt 8 of the lower skate sub-chassis 2. A screw thread 43 is machined at the other end of the pin. The through hole 41 allows a reduction in the weight of the skate which can provide an improvement in performance for skaters and in particular competitive racing or speed skaters, or other sports skaters.

Claims

CLAIMS:

1. A chassis for a personal stand-on conveyance for supporting a person when traversing over a surface, the chassis having a longitudinal axis and comprising: an upper sub-chassis having first attachment means by which a boot or other foot- supporting means can be attached to the upper sub-chassis, and a lower sub-chassis having second attachment means by which a surface-engaging means for engaging the surface can be attached to the lower sub-chassis, the upper sub-chassis being pivotably mounted at a forward portion thereof to the lower sub-chassis for relative rotation, about a transverse axis, against a biasing force provided by a spring means, the spring means comprising a length of resilient material which is attached to or bears against the upper sub-chassis at a first location and bears against the lower sub- chassis at a second location, the relative rotation of the upper and lower sub-chassis flexing the spring means between the first and second locations.

2. A chassis as claimed in claim 1 wherein one side of the spring means bears against the upper sub-chassis at the first location and against the lower sub-chassis at the second location, and an opposite side of the spring means bears against the upper sub-chassis at a third location intermediate the first and second locations.

3. A chassis as claimed in claim 2 wherein the side edges of the front end of the leaf spring lie between and engage respective side walls of the upper sub-chassis at the first and third locations and the side edges of the rear end of the leaf spring lie between and engage respective rear mounting flanges to restrain transverse movement of the upper sub-chassis relative to the lower sub-chassis when the upper sub-chassis is pivoted away from the lower sub-chassis.

4. A chassis as claimed in any one of claim 1 , 2 or 3 wherein the spring means is fixed to the upper sub-chassis at the first location.

5. A chassis as claimed in any one of the preceding claims wherein the spring means is a leaf spring which when relaxed is substantially flat.

6. A chassis as claimed in any one of the preceding claims wherein the surface is a ground or floor surface, the conveyance is a roller skate and the surface-engaging means is a set of at least two rollers.

7. A chassis as claimed in claim 6 wherein the roller skate is an in-line roller skate.

8. A chassis as claimed in any one of claims 1 to 5 wherein the surface is an ice surface, the conveyance is an ice skate and the surface-engaging-means is a runner or blade.

9. A chassis as claimed in any one of claims 1 to 5 wherein the surface is an ice or snow surface, the conveyance is a ski or snow board and the surface-engaging-means is a ski or board.

10. A chassis as claimed in any one of claims 1 to 5 wherein the surface is a water surface, the conveyance is a ski, surfboard or wave board and the surface-engaging-means is a ski or board.

11. A skate comprising: a chassis according to any one of claims 1 to 8, the boot or other foot-supporting means being attached by the first attachment means to the upper sub-chassis, and the surface-engaging means being attached by the second attachment means to the lower sub-chassis.

12. An roller skate axle pin for rotatably supporting a roller in an in-line roller skate, the pin having an axial through hole.

13. The axle pin as claimed in claim 12 wherein the axial through hole has a non- circular transverse cross-section.

14. The axle pin as claimed in claim 13 wherein the through hole has a hexagonal transverse cross-section.

15. The axle pin as claimed in claim 12, 13 or 14 wherein the pin is manufactured from a length of material extruded with the non-circular axial through hole, the outside diameter of the extruded material being reduced over a part of the length of the pin to leave a head at one end, and a screw thread being provided at the other end.