GB2551148A

GB2551148A - A coupled union for sliding over wet surfaces

Info

Publication number: GB2551148A
Application number: GB1609922.8A
Authority: GB
Inventors: Clifford Green Paul
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-06-07
Filing date: 2016-06-07
Publication date: 2017-12-13
Also published as: GB201609922D0

Abstract

A snow ski may comprise two halves 1, 2 which may be connected via a male projection 3 engaging with a female coupling 3a. When the two portions are assembled a vertical joint line (Fig 4b CL) is in line with the front of the binding 7. Thus allowing forces to be concentrated over the joint. The tongue 3 and groove 3a are disposed about the longitudinal centerline or lengthways neutral axis of the ski (Fig 3a and 3b, na). The location of the engagement portions 3, 3a about this axis is intended to reduce excessive flex of the assembled halves preventing gap (Fig 3a and 3b, 5) from opening up when in use. The gap causing drag due to snow build up. A further projection 6a may engage with recess 6b to reduce snow build up. An angled joint face may also be provided to reduce friction (Figs 5a and 5b).

Description

A COUPLED UNION FOR SUDING OVER WET SURFACES

Snow skis, snow boards, water skis and surf boards have similar long slender profiles which travel longitudinally over wet surfaces. The sliding surface is often referred to as the running surface. These sports equipment are too long to transit through automated luggage handling equipment, especially those used in airline passenger terminals, and therefore, classified as oversize luggage, they have to be loaded separately onto the aircraft which often incurs a surcharge When they are transported by road, the vehicle generally requires a roof rack to carry them which significantly increase the aerodynamic drag on the vehicle and fuel consumption.

To construct these sports equipment so they can transit through automated luggage handling equipment and carried inside a vehicle, the overall length must divided and dismantled into shorter sections to reduce the package size. The length that can transit safely through an automated luggage handling systems is about 700mm.

The sliding surfaces of all of these sports equipment are subjected to longitudinal bending moments because the pressure on the front section is much higher because it has to carve out a path for the other sections to follow. A bending moment results in tensile stresses acting along the sliding surface. In the case of a one piece sliding surface, the tensile stress and the corresponding strain increases the overall length of the sliding surface. However, when the sliding surface comprises of separate sections joined together, a gap opens up on the sliding surface where the connection interfaces of the separate runners are joined together by a coupled union and this gap can significantly increase the sliding resistance.

The width of the gap is determined by the position the neutral axis of the moment of inertia of the cross section of the coupled union relative to the sliding surface of the runners. The neutral axis is a plane in the cross section of the coupled union subjected to a bending moment where the compressive stress extending down from the top face of the runners reduces to zero and the tensile stresses increase towards the sliding surface. A bending moment causes the front runner to bend upwards relative to the rear runner and the bent profile of the neutral axis at any position along the longitudinal axis is called the radius of curvature.

To provide a better understanding of the relationship between the bending moments, the position of neutral axis and the radius of curvature, reference are made to the following diagrammatic drawings in which a front runner is connected to a rear runner to form a coupled union. In order to sustain the bending forces transferred from the front runner to the rear runner, the construction of the coupled union must include a bridge connection spanning between the runners. The location of the bridge connection along the longitudinal axis of the sliding surface has a significant influence on the width of the gap.

Fig la, shows a scrap view of a connection interfaces of a front runner 1 and a rear runner 2, connected together with a bridge connection 3 positioned on the top face of the runners forming a coupled union. When a bending moment Bm is applied to the coupled union, the neutral axis na, and radius of curvature Rt are formed about the centreline CL and in the middle cross section of the bridge connection. It can be observed that the radius of curvature at the sliding surface traces an arc between the edges of the connection interfaces on the sliding surface which is shown by the gap dimension gt.

Fig lb, shows a scrap view of a connection interfaces of a front runner 1 and rear runner 2, connected together with a bridge connection 3 positioned in the middle section of the body of the runners to form a coupled union. The longitudinal neutral axis na, and radius of curvature Rm are formed about the centreline CL and positioned about the middle section of the bridge connection. It can be observed that the arc traced between the edges of the gap dimension gm, is much smaller than the gap dimension gt shown in Fig la. Accordingly, the nearer that the neutral axis is positioned to the sliding surface, the smaller the gap that will open up when the runners are bent.

The present invention concerns the two most important features of a coupled union. Firstly, to ensure that when the runners bend, the longitudinal profile of the coupled union along the sliding surface provides a smooth sliding transition from the front runner to the rear runner, and secondly, to locate the coupled union at a position on the sliding surface to minimise the effect of the gap.

Ideally, the edges of the connection interfaces of the coupled union must not increase the sliding resistance when the runners travel over a wet surface. For example, if the front runner lifts off the sliding surface at the position of the gap higher than that of the rear runner, (as shown in Fig la and lb), than the rear runner will have to trace and plough a different path through and along the sliding surface to that of the front runner and this would increase the sliding resistance.

To prevent this situation occurring, it is necessary to ensure that connection interface of the front runner at the position of the gap remains level with, or move down just below the edge of the gap of the rear runner in order that it can travel freely along the same path already carved out by the front runner.

The location of the position of coupled union along the longitudinal axis of the sliding surface will determine the maximum bending stress that can be applied to it. The bending moment is a function of the resultant bending force acting on the front runner multiplied by the distance from the coupled union at which the resultant bending force is acting. Therefore, the bending stress and radius of curvature must be carefully considered when deciding where the coupled union should be located.

The present invention, by way of example only, can be best be understood by a detailed explanation of how the couple union can be constructed for one of the sports equipment previously mentioned. A snow ski has been selected as the loads acting on the ski runners can easily be understood and typify the construction requirements of a coupled union for all the other sports equipment.

The most arduous skiing manoeuvres occur when the skier makes a high speed turn across the fall line of the snow. To carry out a turn, the skier leans inwards into the turn and transfers the body weight onto the inside edges of the skis to press the edges into the surface of the snow to obtain the maximum grip. The more reaction force that can be sustain between the snow and the edges of ski, the more the skier can lean into the turn and the smaller the turning radius becomes. The faster the skier negotiates the turn, the higher the centrifugal force that will be generated between the ski edges and the snow. To maintain stability during making a turn, the skier also leans forwards towards the fall line of the snow and transfers the centre of the skier's body mass towards the front of the ski and the dynamic forces that are generated are transferred to the skis mainly through the front ski boot binding. Accordingly, the sliding surface directly under the front ski boot binding experiences the highest contact force with the snow, and this contact force will produce a localised flattening of the sliding surface and increase the radius of curvature along this section of the ski.

To ensure that the rear edge of the gap on the running surface of the front runner at the connection interface of the coupled union cannot lift up higher than the front edge of the gap of the rear runner, the connection interfaces of the coupled union on the sliding surface must be positioned set back towards the rear runner and offset from the centre line of the radius of curvature of the coupled union. Then, as the front runner is bent upwards, the rear edge of the gap of the front ski runner at the connection interface of the coupled union will have to move in a downwards direction following the radius of curvature, to a position just below the running surface of the rear ski runner.

To explain the geometry of this requirement, reference is made to Figure 2a, 2b, 3a and 3b.

In the partial section of a coupled union shown in Fig 2a, male flap 6 projects along the sliding surface of the connection interface of the front runner 1 to a position beyond the centreline CL of the coupled union and engage into a corresponding female recess formed in the front connection interface of the rear ski runner 2. The bottom leading edge 4 of the flap 6 is level with the bottom corner edge 5 of the recess.

In the partial section of a coupled union shown in Fig 2b, the connection interface between the front runner 1 and the rear runner2 are set on an angle so that the bottom edge 5 of the rear runner and the bottom edge 4 of the front runner are set back towards the rear runner and offset from the centreline CL of the coupled union.

The partial section shown in Fig 3a shows the coupled union in Fig 2a after the runners have been subjected to a bending moment similar to that shown in Fig lb. It can be observed that a gap has opened up on the sliding surface between the edges 4 and 5. However, as the front runner bends upwards, the edge 4 move down below edge 5 to follow the radius of curvature of the sliding surface formed about the centreline CL as shown by the arrowed dimension h.

The partial section shown in Fig 3b, is an enlarged scrap section Fig 2b after the runners have been connected together to form a coupled union and then subjected to the said bending moment, it can be observed, in a similar manner to that described above for Fig 3a, the edge 4 has moved by the arrowed dimension h below the edge 5.

The constructions described above ensures that when the coupled union is subjected to a bending moment the connection interface the front runner cannot lift up higher of the sliding surface than the connection interface of the rear runner, and therefore the rear runner is able to freely travel in the same path carved out by the front runner.

In one embodiment, a male flap extends from the rear end of the sliding surface of the front runner to a position beyond the connection interface of the coupled union and engages into a corresponding female recess formed in the sliding face of the rear runner. When the coupled union is subject to a bending moment, the flap will try to move down below the face of the gap on the centre runner. However, as previously mentioned the dynamic loads acting on the front ski binding will prevent the flap from moving downwards and pressed against the sliding surface and retained into the said recess. Although a small gap may still be present on the sliding surface, the edges of the gap will remain level with each other.

In one embodiment of the present invention, the distal end of the centre ski runner has a male projection extending from the connection interface, which on assembly engages into a corresponding female recess formed in the distal end of the connection interface of the front ski runner. This construction provides an additional strength to the bridge connection across the runners and increases the bending load capacity of the coupled union.

In one embodiment of the present invention, the coupled union is constructed with the connection interfaces set on an angle to the longitudinal axis such that they intersect the sliding surface of the runners set back towards the rear runner and offset from the centre line of the radius of curvature when the runners bend.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:

Figure 4a, is a partial cross section of a front and rear runner in alignments ready to be connected together to form a coupled union. A male flap extends from the rear end of the sliding surface of the connection interface of the front runner and the rear runner has a corresponding female recess form in the sliding surface to receive the flap.

Figure 4b is a partial cross section of the front and centre ski runner ski shown in Fig 4a after the connection interfaces ski runners have been connected together to form a coupled union.

Figure 5a is a partial cross section of a rear runner having a male projection extending from the distal end of the connection interface which on assemble engages into a corresponding female recess formed in the distal end of the front runner. The runners are shown in alignment with each other before being connected together to form a coupled union. The connection interfeces of the coupled union of the runners are set on an angle such that they intersect the sliding surface of the ski runner set back towards the centre ski runner and offset from the centre line of the radius of curvature when the ski is bent.

Figure 5b is a partial cross section of the rear and front runners shown in Fig 5a after they have been connected together to form a coupled union.

Figure 6a is a partial cross section of the runners in alignment ready to be connected together to form a coupled union. The front runner has a male flap extending from the distal end of the connection interface for connection with a corresponding female recess formed in the front distal end of the connection interface of the rear runner.

Figure 6b is a partial cross section of the rear and front runner shown in Fig 6a after they have been connected together to form a coupled union.

In the embodiment shown in Fig 4a, the rear runner 2 and the front runner 1 are positioned in alignment with each other ready to be connected together to form a coupled union. A bridge connection 3 is permanently fixed within the central section of the front runner 1. A male flap 6a with a leading edge 4 projects long the sliding surface of the front runner 1 to a position beyond the connection interface of the rear runner 2. A female recess 6b is formed in the sliding surface of the rear runner 2 to receive the flap 6a. The front ski boot binder 7 is positioned on the top face of the rear runner and immediately above the recess 6b. An internal passageway 3a is formed in the central section of the connection interface of the rear ski runner to receive the bridge connection 3.

Fig 4b, shows the runners 1 and 2 shown in Fig 4a connected together to form a coupled union and clamped together by a linkage mechanism (not shown) which connects to the bridge connection 3 through the internal passageway 8 formed in the rear runner and pulls the bridge connection 3 along the internal passageway 8 and passing underneath the front boot ski binder 7 until the coupled union is firmly clamped together. The male flap 6a is now located in a corresponding female recess 6b formed in the front end of the rear runner2. The arrow F represents the resultant vertical force component generated by the skier as previously explained. The vertical force F will be reacted on the sliding surface about the position of the flap 6a and will force the flap back into the recess 6b and keep the edges 4 and 5 level with each other.

In the embodiment shown in Fig 5a, the rear runner 2 and the front ski runner 1 are positioned in alignment with each other ready to be connected together. The bridge connection 3 is permanently fixed within the central section of the front runner 1. A corresponding internal passageway 3a is formed in the connection interface of the central section of the rear runner 2 ready to receive the bridge connection 3a. A male projection 9a extends from the distal front face of the connection interface of the rear runner 2. A corresponding female recess 9b is formed in the distal end face of the connection interface of the front runner 1. The connection interface of the runners 1 and 2 are set on an angle relative to the sliding surface as shown by edges 10a and 10b.

Fig 5b, shows the runners 1 and 2 shown in Fig 5a, connected together to form a coupled union and clamped together by a linkage mechanism (not shown) which connects to the bridge connection 3 through the internal passageway 8 formed in the rear runner which pulls the bridge connection 3 along the internal passageway 3b until the coupled union is firmly clamped together. The resultant vertical force F generated by the skier is reacted on the sliding surface at the position of the coupled union and will force the edge 10b back level with the edge 10a as explained in the description for Fig 3b.

In the embodiment shown in Fig 6a, the rear runner 2 and the front ski runner 1 are positioned in alignment with each other ready to be connected together. The bridge connection 3 is permanently fixed within the central section of the front runner 1. A corresponding internal passageway 3a is formed in the central section of the connection interface rear runner 2. A male projection 9a extends from the distal front face of the connection interface of the rear runner 2 and corresponding female recess 9b is formed in the distal end face of the connection interface of the front runner 1. A flap 6a extends along the sliding surface of the front ski runner 1.

Fig 6b shows the runners 1 and 2 connected together to form a coupled union and clamped together by a linkage mechanism (not shown) which connects to the bridge connection 3 through the internal corridor 8 formed in the rear runner which pulls the bridge connection 3 along the internal passageway 3b until the coupled union is firmly clamped together. When the runners are subjected to a bending moment, the flap 6a will tend to move down as shown in Fig 3a, however, the resultant force F generated by the skier is reacted on the sliding surface at the position of the coupled union and will force the male flap back into the female recess 6b and keep the edge 10b level with the edge 10a.

Claims

1. A coupled union to assemble together the connection interfaces of a front runner (1) and a rear runner (2), secured together by a clamping mechanism to form a longitudinal sliding surface, characterised by that when the runners are subjected to a bending moment, the bottom edges of connection interfaces of the runners intersect the sliding surface at a position (4,5) offset from the centre line of the radius of curvature (CL) so that the bottom edge of the connection interface of the front runner (4) remains level with, or moves just below, the bottom edge of the connection interface of the sliding surface of the rear runner (5) enabling the rear runner to freely travel in the same path carved out by the front runner.

2. A coupled union according to claim 1, wherein a male flap (6a) having a leading edge (4) which projects along the sliding surface of the front runner (1) to a position beyond the connection interface of the front runner and engages into a corresponding female recess (6b) having rear edge (5) formed in the sliding surface of the rear runner (2) so that when the runners are subjected to a bending moment, the leading edge (4) will try to move down relative to rear edge (5) but is constrained from doing so by the force (F) exerted by the rider on the coupled union keeping it pressed against the sliding surface and level with the rear edge (5).

3. A coupled union according to claim 1, wherein the connection interface (10b) of the front runner (1) and connection interface (10a) of the rear runner (2) are set on an angle relative to the longitudinal axis of the runners such that they make contact on the sliding surface set back from the front runner (1) beyond the centreline (CL) of the coupled union so that when the runners are subjected to a bending moment the connection interface (10b) moves in a downwards direction relative to the connection interface (10a) enabling the rear runner (2) to freely travel in the same path as the front runner(l).

4. A coupled union according to claim 1, wherein the coupled union is positioned on the longitudinal axis of the rear runner immediately adjacent to the bind ing (7) securing the rider to the runners.

5. A coupled union according to claim 1, wherein a bridge connection (3) positioned within the central body of the runners (1,2) spans across the longitudinal axis of the connection interface of the runners (1,2) and sustains the bending moments acting on the runners.