[0002] The invention further relates to a ring for a pushing stick, the stick ring comprising: a fastening part for fastening the stick ring to the lower end of a shaft of the pushing stick, a ring frame attached to said fastening part and extending to the front of the fastening part as viewed in the direction of travel, and at least one spike provided on the side of the lower surface of the ring frame.

BACKGROUND OF THE INVENTION [0003] Typically, ski sticks and the like are equipped with a spike as an extension at the lower end of a shaft. A problem with the conventional ski sticks is that the shaft cannot be charged with a sufficient push force during a push, which makes the push less efficient. Since skiing has become a speedier sport as the tracks and skis have developed, the ski sticks are also expected to show some new characteristics.

[0004] FI publication 82194 discloses an oval ring for a ski stick, the central axis of the ring pointing in the direction of skiing. As viewed in the direc- tion of skiing, the ring extends to the front of the stick. Since the spike is ar- ranged as an extension of the shaft, this solution enables no push force to be stored in the shaft in order to provide an efficient push.

BRIEF DESCRIPTION OF THE INVENTION [0005] An object of the present invention is to provide a novel and improved pushing stick and a ring for the same.

[0006] The pushing stick of the invention is characterized in that as viewed in the longitudinal direction of the stick, the ring frame is a bar-like pro-

jection pointing in the direction of travel, whose first end is attached to the fas- tening part and whose second end is free; that one or more spikes are ar- ranged at least in the area of the second end of the ring frame at a distance from the central axis of the shaft; that the ring frame is arranged to serve as a lever arm between said spike and the shaft, whereby a bending moment is ar- ranged to be formed in the ring frame when the push force in the direction of the longitudinal axis of the shaft is directed to the stick; and that the ring frame is a substantially rigid object in terms of bending, arranged to transmit the bending moment being formed to the lower end of the shaft.

[0007] The ring for a pushing stick according to the invention is fur- ther characterized in that as viewed from above, the ring frame is a bar-like projection pointing in the direction of travel, whose first end is attached to the fastening part and whose second end is free; that one or more spikes are ar- ranged at least in the area of the second end of the ring frame at a distance from the fastening part, whereby the ring frame is arranged to form a lever arm between said spike and the fastening part; and that the ring frame is a substantially rigid object in terms of bending.

[0008] An essential idea underlying the invention is that the lower end of a pushing stick is provided with a stick ring comprising a projection-like ring frame. As viewed in the direction of travel, the ring frame is directed for- wards, and the area of its free end is provided with at least one spike which, as viewed in the longitudinal direction of the stick, constitutes the lowest section of the stick. The spike is then located at a distance from the central axis of the shaft and the ring frame thus serves as a lever arm; subsequently, a bending moment is formed when the stick is subjected to a push force. Being a rigid object in terms of bending, the ring frame is capable of transmitting the bend- ing moment being formed to the lower end of the shaft. Furthermore, since the spike is located at a distance from the central axis of the shaft, the stick makes a larger arc when being tilted than if the spike serving as the fulcrum for the tilt were arranged as an extension of the central axis of the shaft.

[0009] An advantage of the invention is that the forward-pointing ring frame enables the radius of the arc made by the stick when being tilted to be larger than the length of the stick, which means that tilting the stick results in a lengthening effect on the stick and a more efficient push. Furthermore, when the ring frame serves as a lever arm between the tip spike and the shaft, the push force generates a bending moment to be transmitted to the lower end

of the shaft which bends under the impact of said bending moment, thus con- verting some of the push force into a spring force. The spring force stored in the elastically bending shaft of the stick is released towards the end of a push, making it more efficient.

[0010] An essential idea underlying a first preferred embodiment of the invention is that as viewed in the longitudinal direction of the stick, the free end of the ring frame extends farther than the end of the ring frame facing the fastening part. This ensures that together with the spike, the tip of the ring frame always forms the outermost section of the lower end of the stick, thus being the first element to meet the surface when being pushed.

[0011] An essential idea underlying a second preferred embodiment of the invention is that the free end of the ring frame is provided with a projec- tion-like claw that extends a distance downwards from the lower surface of the stick frame. The claw may serve as a fastening part for a spike. On the other hand, the claw itself may serve as a spike.

[0012] An essential idea underlying a third preferred embodiment of the invention is that the fastening part is an elongated sleeve into which the shaft of the stick can be inserted. Furthermore, the fastening part is elastically flexible in its longitudinal direction, which means that no discontinuity, which is disadvantageous to the strength of the structure, will be formed between the fastening part and the shaft.

BRIEF DESCRIPTION OF THE DRAWINGS [0013] The invention will be described in closer detail in connection with the accompanying drawings, in which [0014] Figure 1 is a schematic side view showing a pushing stick of the invention, [0015] Figure 2 schematically shows a lengthening effect on a push produced by the pushing stick of the invention, [0016] Figure 3 is a schematic top view showing the pushing stick according to Figure 1, [0017] Figure 4 is a schematic side view showing a ring for a push- ing stick according to the invention, [0018] Figure 5 is a schematic view showing a cross section of the ring for a pushing stick according to Figure 4 taken along line G-G,

[0019] Figure 6 is a schematic bottom view showing the ring for a pushing stick according to Figure 4, [0020] Figure 7 is a schematic side view showing a second stick ring according to the invention, [0021] Figure 8 is a schematic top view showing an extension part that can be arranged in the stick ring of the invention, [0022] Figure 9 is a schematic side view showing the extension part of Figure 8, [0023] Figures 10 to 12 are schematic side views showing a push- ing stick according to the invention, equipped with an extension part, [0024] Figure 13 is a schematic top view showing an extension part, [0025] Figure 14 is a schematic side view showing a pushing stick of the invention and Figure 15 shows a corresponding pushing stick as seen in the direction of travel, and [0026] Figures 16 and 17 are schematic side views showing further possible stick ring structures according to the invention.

[0027] For the sake of clarity, the figures show the invention in a simplified manner. Like reference numbers identify like elements.

[0028] It is to be noted that in the present application, a pushing stick refers to an exercise means enabling a push force produced by a person with his or her hand to be conveyed to a surface in order to make the person's movement more efficient. The pushing stick of the invention is thus suited for use in cross-country skiing, Alpine skiing, roller skiing, roller skating, long dis- tance skating, Nordic walking, snowshoeing and other such forms of exercise.

DETAILED DESCRIPTION OF THE INVENTION [0029] The pushing stick 1 shown in Figure 1 comprises an elon- gated shaft 2, which is preferably a tube having a circular or an elliptical cross- section and made of a fibre-reinforced plastic material. The upper end of the shaft 2 is provided with a handle part 3 typically comprising a fastening ele- ment 4, such as a fastening strap, for attaching the stick 1 to a user's hand.

Alternatively, in place of a fastening strap, the handle part 3 may comprise a glove-like fastening element 4 shown in Figure 2, into which a hand is inserted and tightened. The handle part 3 determines the operating direction of the stick since the handle part 3 is typically shaped to be worn on the hand only in one predetermined position. In addition, the fastening elements 4 of the handle part

3 determine the way in which the stick is directed when in use. The direction of travel is designated by a reference A in the figure. Furthermore, the lower end of the stick 2 is provided with a stick ring 5 attached to the shaft 2 by a fasten- ing part 6. The fastening part 6 is preferably an elongated sleeve into which the lower end of the shaft 2 is inserted. The strength of the joint between the fas- tening part 6 and the shaft 2 can be secured by glue, for example. Further- more, the stick ring 5 comprises a ring frame 7 transverse to the longitudinal direction B of the shaft 2; as viewed in the longitudinal direction B of the shaft 2, the ring frame 7 is a bar-like projection. A first end 8 of the ring frame 7 is attached to the fastening part 6 while a second end 9 is free. As can be seen in Figure 1, the ring frame 7 points towards the direction of travel A, which means that the ring frame 7 resides substantially at the front of the stick 1 ex- clusively and the longitudinal axis of the ring frame 7 is substantially parallel with the direction of travel A. The side of the lower surface 10 of the second end 9 of the ring frame 7 is provided with at least one spike 11. The spike 11 thus constitutes the lowest section of the stick 1, which means that the spike is the first element to touch a surface 12 when a push F is carried out by the stick 1. Since the spike 11 is located at a distance C from the central axis of the shaft 2, a push force F causes a bending moment to be formed in the ring frame 7. The distance C is preferably 3 to 15 cm. Thanks to the structure and/or the manufacturing material of the ring frame 7, it is a rigid object in terms of bending, thus capable of transmitting the bending moment caused by the push force F to the fastening part 6 and further to the shaft 2. The lower end of the shaft 2 then bends according to the broken line 13 in Figure 1, which, for the sake of clarity, is shown in a highly exaggerated manner, caus- ing a spring force to be stored in the elastically flexible shaft 2. The spring force is released towards the end of the push, making it more efficient. The spring force and the utilization thereof are preferably taken into account when the shaft 2 is designed. Typically, the shaft 2 is manufactured by winding rein- forced fibres impregnated with a plastic material around a mandrel or a corre- sponding frame. The bending stiffness and other characteristics of the shaft 2 can then be adjusted in a relatively simple manner by modifying the winding angle of the reinforced fibres, the number of wound rounds and by using differ- ent reinforced fibre materials, such as carbon and aramid fibres. The stick ring 5 is preferably made of a plastic material by injection moulding. The spike 11 or spikes are preferably made of metal and they can be attached to fastening

points provided in the second end 9 of the ring frame 7. Alternatively, the spike 11 can be a part integrated into the ring frame 7, made of the same material as the ring frame 7 or different material than the ring frame 7. The material, sizing and shape of the spike 11 are selected according to the purpose of use of the pushing stick 1. A skating stick and a ski stick, for example, utilize a sharp spike 11 to ensure a good grip on ice as well. On the other hand, a spike 11 in sticks for Nordic walking, for example, may be provided with a blunt tip and equipped with an appropriate friction surface in order to increase the friction between asphalt and the spike 11.

[0030] In Figure 2, the stick 1 is shown in a tilted position to enable the lengthening effect provided by the ring frame 7 pointing towards the direc- tion of travel A to be seen. When the upper end of the shaft 1 is tilted in direc- tion D with respect to the spike 11, the upper end of the stick 1 turns along the curve drawn by the radius designated by the broken line 14 in Figure 2. When the stick is being tilted, its effective length is the oblique distance from the spike 11 to the handle part 3 shown by the broken line 14, and in the stick ac- cording to the invention, this distance is always longer than distance E in the direction of the longitudinal axis of the stick 1. The magnitude of the lengthen- ing effect depends on the length of the ring frame 7 and, subsequently, on the distance at which the spike 11 resides from the central axis of the shaft 2. A user gets the feeling that tilting the stick makes the stick grow longer, in which case the user, utilizing this characteristic, is capable of lengthening the effec- tive time of a push, thus making his or her pushes more efficient.

[0031] At the outset of a push, the stick 1, as shown in Figure 1, is in an upright position and the force component pointing towards the direction of travel A is low. The shaft 2 is thus charged with a push force, the force then being released towards the end of the pushing motion, the stick 1 being tilted towards the direction of travel A, as shown in Figure 2. Thus, the force compo- nent effective towards the direction of travel A is at its highest towards the end of the push.

[0032] Figure 3 is a top view showing the pushing stick according to Figure 1. Figure 3 clearly shows the projection-like structure of the ring frame 7. Thanks to the projection-like structure of the ring frame 7, the shaft 2 bends towards a predetermined direction in a controlled manner, which means that the shaft 2 can be stiffened in the particular direction. This enables the danger of the shaft 2 being buckled, which is a common situation in connection with

the conventional sticks wherein the spike 11 resides in the extension of the shaft 2, to be avoided.

[0033] As seen from the side, the shape of the stick ring 5 shown in Figure 4 is substantially a triangle. The ring frame 7 is at its widest at the first end 8 facing the fastening part 6, tapering towards the second end 9. The cross-section of the ring frame 7 is thus arranged to increase towards the shaft. The ring frame 7 forms a lever arm, and the bending moment is at its highest at the end facing the fastening part 6. A downwards-pointing projec- tion-like claw 16 is arranged at the second end of the ring frame 7 for the spike 11. The ring frame 7 is arranged obliquely at the lower end of the shaft 2, in which case the second end 9 of the ring frame extends farther in the longitudi- nal direction of the stick 1 than the first end 8. This, together with the down- wards-pointing claw 16, ensures that the spike 11 or spikes at the front of the ring frame 7 is/are always the first element or elements to touch the surface 12. On the other hand, it is not necessary to equip the claw 16 with a separate spike 11 but the claw itself may also serve as a spike. It can be further seen in Figure 4 that as viewed in the direction of travel A, the lower surface 10 of the ring frame 7 is preferably downwardly convex, so its shape corresponds with the curvilinear tilting motion of the stick 1.

[0034] Figure 4 further shows a preferred structure of the fastening part 6. The fastening part 6 is an elongated sleeve into which the lower end of the shaft 2 can be inserted. The joint between the fastening part 6 and the shaft 2 may be either a fixed one or it can be arranged such that different stick rings 5 can be attached to the shaft 2 as required. A so-called bayonet fixing can be applied to the joint. The backside surface of the fastening part 6 shown in Figure 4 is equipped with transverse indentations 30, which enables the fas- tening part 6 to bend a distance in the direction of its longitudinal axis. Conse- quently, no sharp discontinuity is formed between the shaft 2 and the fastening part 6 but the fastening part 6 at least to some extent balances the forces, which is why the structure of the shaft 2 becomes more durable against loads.

Instead of using indentations 30, the fastening part 6 can be made flexible in the longitudinal direction by using appropriate dimensions and materials for the fastening part. Furthermore, the fastening part 6 preferably extends higher than the joint between the ring frame 7 and the fastening part 6, which in part also reduces the strain the shaft 2 is subjected to. The cross-section of the shaft 2 may also be elliptical, which makes it more tolerant against bending in

the direction of travel A. The indentations 30 also lighten the stick ring structure and further alleviate the fastening of the shaft 2.

[0035] Figure 5 shows a cross-section of the ring frame 7 taken along line G-G. At the bottom of the cross-section lies a triangular bottom part 7a above which, in turn, is provided a plate-like upper part 7b whose cross-section resembles a rectangle arranged in an upright position. The lower surface 10 of the bottom part 7a then forms a supporting surface large enough more often than not to prevent the stick ring 5 from submerging into at least a relatively hard surface, such as tamped track surface. A stick ring 5 intended for a hard surface, such as a road, does not have to take the size of the sup- porting surface into account but a most important aspect in the sizing of the bottom part 7a is to make the ring frame 7 sideways stiff enough. The maxi- mum width of the bottom part 7a preferably ranges between 7 and 10 mm. Fur- thermore, the upper part 7b can be a relatively narrow structure horizontally, even as narrow as 2 to 5 mm, which means that it is light but at the same time extremely stiff in terms of vertical bending. The air resistance of the cross- section as described above is low.

[0036] Figure 6 is a bottom view of the stick ring 5. The lower sur- face 10 of the ring frame 7 may be provided with projections 15 to improve the grip between the stick ring 5 and the surface 12. Although the ring frame 7 is a relatively narrow projection-like bar, thanks to the length of the ring frame 7 the surface area of the lower surface 10 of the ring frame is large enough to bear the stick on most surfaces 12.

[0037] Figure 7 shows still another stick ring 5 equipped with an extension part 17. As can be seen in Figures 8 and 9, the extension part 17 is a plate-like part arranged on the side of the lower surface 10 of the ring frame 7. The surface area of the extension part 17 is larger than that of the lower sur- face 10 of the ring frame, which means that the stick can be prevented from submerging into a soft surface on account of the push force F. Such an exten- sion part 17 can be used when moving in soft snow, a wood or on a bog, for example. The extension part 17 may be arranged fixedly in the stick ring 5 or it can be an easily detachable and mountable accessory. The extension part 17 is arranged in the area of the second end 9 of the ring frame 7 by means of a hinge 18, in which case the extension part 17 is able to turn a distance indi- cated by angle H in Figure 7 between the lower surface 10 of the ring frame 7 and the broken line 19 in Figure 7. When the stick 1 is lifted, the hinge 18 en-

ables the extension part 17 to turn such that it readily ascends with the front edge first also when submerged in soft snow, for example. Furthermore, since the hinge 18 enables the extension part 17 to move with its front edge first be- tween the pushes, the air resistance caused by the extension part 17 is low even if the extension part may be quite large.

[0038] Figure 8 shows that the extension part 17 may comprise openings 20, which means that despite being large it can be light. The front 17a of the extension part 17 is provided with two upwards-pointing lugs 21 at a distance from each other that are equipped with a transverse opening 22. Fur- thermore, the second end 9 of the ring frame 7 is provided with a transverse opening 23 on the backside of the claw 16, as can be seen in Figure 7. A hinge pin 24 is arranged through the openings 22 and 23 to pivotally connect the stick ring 5 and the extension part 17 with one another. During a push, the extension part 17 is supported against the lower surface 10 of the ring frame 7.

The extension part 17 is preferably made of a plastic material by injection moulding.

[0039] Figure 10 shows a pushing stick equipped with an extension part 17. The front of the stick ring 5 comprises a spike 11 arranged through an opening in the extension part 17 such that the spike 11 is supported against the ground. At the outset of a push, the ring frame 7 supports the extension part 17 into a correct position such that the extension part 17 is substantially at right angles to the axis of the stick tube. The extension part 17 then prevents the stick 1 from submerging into a soft surface in the most advantageous man- ner. Furthermore, a hinge or a joint 30 around which the stick is allowed to turn during the push is provided between the pushing stick 1 and the extension part 17. Despite the turning, the spike 11 or spikes at the front of the ring frame 7 retain their contact with the surface while the extension part 17 lies substan- tially parallel with the surface.

[0040] In Figure 11, the stick 1 is shown towards the end of a push when the stick tube 2 is tilted with respect to the extension part 17. During the push, the stick tube 2 becomes charged with spring force, which is illustrated by a bend 13 in the stick tube 2 in Figure 11. Figure 12 shows a situation wherein the push is completed and the stick 1 is being lifted in direction J in order to move the stick 1 into a new position for a next push. The joint 30 al- lows the rear end of the extension part 17 to drag against the surface while the stick is being moved, in which case part of the mass of the extension part is

directed to the surface during the movement. Then, even if the extension part 17 is large, or even if snow or dirt is stuck to the extension part 17, the stick 1 is still light to handle. If the extension part 17 sinks into a soft surface, such as deep snow, it can easily be lifted up because, thanks to the joint 30 at the front of the extension part 17, the extension part 17 ascends from the snow with the tip first, in which case the surface area resisting the lifting in direction J is small. The solution shown in Figures 10 to 12 is preferably applied to long dis- tance and Telemark skiing.

[0041] Figure 13 is a top view showing the extension part of the stick 1 shown in Figures 10 to 12. The extension part 17 is an elongated, sub- stantially plate-like object whose front is upwardly oblique. The extension part 17 may, for example, be 25 cm long and 12 cm wide, or it may be 35 cm long and 15 cm wide, for example. The extension part 17 comprises openings 20 to lighten the structure. The extension part 17 is preferably made of a plastic ma- terial by injection moulding, for example. The front of the extension part 17 comprises an opening 31 through which a spike 11 is arranged. If the lower surface of the ring frame 7 comprises several spikes 11, each spike is provided with an opening 31. Furthermore, the joint 30 and the opening 31 can be di- mensioned to allow the front of the ring frame 7 to turn to the side of the lower surface of the extension part 17 during a push. The joint 30 may comprise two lugs, for example, and an axis pivotally arranged therebetween. Preferably, the joint between the extension part 17 and the ring frame 7 enables the extension part 17 to be easily detached for replacement or a downhill run. The extension part 17 is preferably an accessory to be attached to the basic stick 1 when necessary.

[0042] Figures 14 and 15 show a stick ring 5 for Nordic walking in particular. The ring frame 7 is preferably about 4-5 cm long. Furthermore, the front of the ring frame 7 comprises two spikes 11 located side by side trans- versely to the longitudinal axis of the ring frame 7. The two spikes 11 make the stick 1 steady to handle sideways also when moving on a relatively hard sur- face.

[0043] Figures 16 and 17 show a stick ring 5 comprising a tip spike 11 a at the front of the ring frame 7 and a heel spike 11 b in the extension of the stick tube 2. In Figure 16, the spikes 11 a and 11 b extend equally far in the lon- gitudinal direction of the stick 1 whereas in Figure 17, the heel spike 11b ex- tends farther than the tip spike 11 a. The stick ring 5 equipped with the tip spike

and the heel spike 17 is suited to Alpine skiing in particular because the tip spike 11 a and the spring force charged into the stick tube 2 therethrough can be utilized at the outset of a downhill run when the sticks are used for a more powerful take-off. The heel spike 11b, in turn, is utilized in controlling the run, for example in slalom turns. Furthermore, the ring frame 7 may be shaped as the ring frame shown in Figure 15, i. e. it can be an upwards tapering structure, in which case it is aerodynamically advantageous. Such a ring frame 7 can serve as a wing at high speeds to reduce whirls of air and to stabilize the skier.

[0044] The drawings and the related description are only intended to illustrate the idea of the invention. In its details, the invention may vary within the scope of the claims.