Ski pole

Abstract

The invention is directed to a ski pole comprising a longitudinal shaft. The shaft includes a cross-section that comprises: a first part including a curved first portion arranged symmetric about a cross-sectional centerline (CL) of the shaft, and a second part including a second portion arranged symmetric about the cross-sectional centerline.

Wherein the first part is connected to the second part by side parts including side portions, each side part comprises a first end connected to an end of the first part and a second end connected to an end of the second par, each connection between the side parts and the first and second parts forms a corner, such that there are total four corners in the cross-section of the shaft.

Claims

1. A ski pole comprising a longitudinal shaft, the shaft includes a cross-section that comprises: a first part including a curved first portion arranged symmetric about a cross-sectional centerline of the shaft, and a second part including a second portion arranged symmetric about the cross-sectional centerline, wherein the first part is connected to the second part by side parts including side portions, each side part comprises a first end connected to an end of the first part and a second end connected to an end of the second part (4), each connection between the side parts and the first and second parts forms a corner, such that there are total four corners in the cross-section of the shaft.

2. The ski pole according to claim 1, wherein the curved first portion is a circular arc defined by an angle θ and forms part of a circumference of a circle with radius.

3. The ski pole according to claim 2, wherein the angle θ is less than 180 degrees.

4. The ski pole according to claim 2, wherein a length of the second portion is equal to or less than the radius of the curved first portion.

5. The ski pole according to claim 2, wherein a length of the circular arc is 3 times the radius, and the length of the second portion is one time the radius.

6. The ski pole according to claim 2, wherein the curved first portion and each of the four corners are located on or at an outer circumference of the circle with the radius.

7. The ski pole according to claim 1, wherein the second part (4) and each of the side parts are slightly curved portions.

8. The ski pole according to claim 1, wherein the second part (4) and side parts are straight portions.

9. The ski pole according to claim 8, wherein the shaft comprises a top end and a bottom end, wherein the radius is gradually decreasing from the top end towards the bottom end.

10. The ski pole according to claim 9, wherein the top end of the shaft comprises a cross-section according to any one of claims 1-8, and the bottom end is provided with a circular cross section.

11. The ski pole according to claim 10, wherein the cross-sectional shape of the top end of the shaft gradually changes towards the cross-sectional shape of the bottom while moving towards the bottom end.

12. The ski pole according to claim 11, wherein at a distance from the bottom end of the shaft the shaft is provided with a section with a slightly distorted diameter compared to the section immediately preceding and following said distorted diameter section of the shaft.

Description

FIGURES

[0061] The description above, as well as further objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of the preferred embodiment which should be read in conjunction with the accompanying drawings in which:

[0062] FIG. 1 shows a cross-section of the shaft of a ski pole having four corners and where the outer perimeter is illustrated by a line.

[0063] FIG. 2 shows a cross-section of the shaft of a ski pole having four corners with an inner and outer perimeter.

[0064] FIG. 3 shows the cross-section of the shaft of a ski pole in relation to a circle with radius R.

[0065] FIG. 4 shows different views of the shaft for a ski pole and the cross-sectional views at different sections of the shaft.

[0066] FIG. 5 shows a table of stiffness (span) and breaking strength test results in relation to a version of the triangular shaped cross-section.

[0067] FIG. 6 shows a table of stiffness (span) and breaking strength test results in relation to another version of the triangular shaped cross-section.

[0068] FIG. 7 shows a table of stiffness (span) and breaking strength test results in relation to a cross-sectional shape of the present invention.

[0069] FIG. 8 shows a summarized table with the average test values for triangular shape versus the four corners shape of the present invention.

[0070] FIG. 9 shows test results from wind tunnel with different cross-sectional shapes at different speed.

[0071] FIGS. 10 a-d shows graphically the test results of FIG. 8.

DETAILED DESCRIPTION OF THE FIGURES

[0072] The FIG. 1 shows a cross-section of a longitudinal shaft for a ski pole. The cross-sectional shape is illustrated by four lines interconnected, where the lines defines the following: a first part 3, a second part 4 and two side parts 5. The side parts 5 are illustrated by dotted lines in FIG. 1 for illustration purposes.

[0073] The first part 3 may be a front part and the second part 4 may be a back part of the cross-section of the ski pole viewed in the moving direction of the skier. The side part 5 connects the front part to the back part.

[0074] The front part 3 may be a curved portion arranged symmetric about the centerline (CL) of the cross-section. The curved portion may be a curved line having two ends distal from each other and connected to respective ends of the side parts 5′, 5″ defining a corner 6 at the intersection between the lines 3,5.

[0075] The side parts 5 connect the front part 3 to the back part 4 and may be a straight line with one end connected to the one end of the curved line of the front part 3 and opposite end connected to the one end of the back part 4.

[0076] The back part 4 may be a horizontal straight line arranged symmetric about the centerline (CL) of the cross section of the ski pole. The length of the back part 4 may be shorter than a distal length between the ends of the front part 3 such that the side parts 5 has an outward rise (incline outwards) when moving from the pack part 4 to the front part 3. The outward rise meaning the rise is directed out from the center of the cross-sectional shape.

[0077] FIG. 2 shows a cross-section 2 of a longitudinal shaft 1 for a ski pole with a wall thickness defining an inner and outer perimeter, the inner and outer perimeters having the same shape or substantially same shape.

[0078] The shaft 1 includes a cross-section 2 that comprises a first part 3 with a curved first portion arranged symmetric about a cross-sectional centerline (CL) of the shaft 1, and a second part 4 with a second portion 4 arranged symmetric about the cross-sectional centerline (CL).

[0079] The first part 3 is connected to the second part 4 by side parts 5 with side portions, each side part 5 comprises a first end 5′ connected to an end of the first part 3 and a second end 5″ connected to an end of the second part 4, each connection between the side parts 5 and the first and second parts 3, 4 forms a corner 6, such that there are total four corners 6 in the cross-section 2 of the shaft 1.

[0080] As shown in FIG. 2 the four corners 6 may be rounded such that there are no sharp edges for better aerodynamic properties. Rounded edges may also be easier to manufacture using layers of carbon fibers.

[0081] In terms of strength and aerodynamics, the optimum solution for a ski pole is achieved according to the invention in a manner such that the cross-section of the shaft comprises four corners 6.

[0082] The curved first portion and/or the second portion may be symmetric about the centerline (CL). The first portion, the second portion and the side portions may all be symmetric about the centerline (CL).

[0083] The curved first portion may be a circular arc having length L and defined by an angle θ and forms part of a circumference of a circle with radius (R). Thus, this means that all points of an outer perimeter of the cross-sectional shape lies at or within a circumference of circle with radius (R).

[0084] FIG. 2 shows that the curved first portion is a circular arc with radius (R). The circle is illustrated by dotted lines and enclosing the entire cross-sectional shape 2 of the shaft 1.

[0085] The curved first portion may be the arc of a semi-circle. FIG. 3 shows that the curved first portion may be circular arc which constitutes less than a semi-circle. Thus, the angle θ is less than 80 degrees.

[0086] The length of the second part 4 may be equal or less than the radius (R) of the curved first portion. This means that the cross-sectional shape gradually narrows in from the curved first portion to the second part 4.

[0087] Furthermore, the two times radius (R) of the curved first portion may be equal to the greatest width of the cross-section of the shaft. This means the curved front portion defines an of a circle with radius (R), and that the greatest width of the cross-section of the shaft does not exceed the 2x radius (diameter) of the circle.

[0088] FIG. 3 also shows that the curved first portion and each of the four corners may all be located on or at an outer circumference of the circle with the radius (R). Hence, each of the four corners 6 are points located on or at a circumference of a circle.

[0089] The side parts and the second part may be straight, curved portions or a combination thereof. In an embodiment, the back and side portions are slightly curved portions as shown in FIGS. 2 and 3.

[0090] The curved first portion (first part 3) may be the front part of the ski pole, meaning that it is headed forward in the skiing direction. Thus, the second part 4 is the back part of the ski pole.

[0091] The second part 4 may be the front part of the ski pole, meaning that it is headed forward in the skiing direction. Thus, the curved first part is the back part 4 of the ski pole.

[0092] FIG. 4 shows different views of a shaft 1 for a ski pole and the cross-sectional 2 views at different sections of the shaft 1.

[0093] The longitudinal shaft 1 may comprise a top end and a bottom end, wherein the radius (R) or cross-sectional width of the shaft 1 is gradually decreasing from the top end towards the bottom end.

[0094] Section B-B shows a cross-section 2 of the top end of the shaft viewed downwards towards the bottom end.

[0095] Section C-C shows a section closer towards the bottom end of the shaft where the cross-section of the shaft still has a significant four corners shape.

[0096] Wherein in the section D-D the cross-section of the shaft is gradually adopting a circular cross-section.

[0097] Thus, the top end of the shaft of the present invention, may comprise a cross-section having four corners 6, and wherein the bottom end is provided with a circular cross-section. The cross-sectional shape of the top end of the shaft may gradually change towards the cross-sectional shape of the bottom end.

[0098] At a distance from the bottom end of the pole shaft, the pole shaft may be provided with a section with a slightly distorted diameter compared to the section immediately preceding and following said distorted diameter section 9 of the pole shaft. The section is shown in detail A, in FIG. 4.

[0099] This diameter distorted section 9 may function as a friction increasing feature to enhance fixation of a replaceable means for limiting the sinking of the ski pole into ground surfaces, such as a disc structure or a snow guard, when the ski pole is used for skiing or walking.

[0100] The ski pole may further be configured with features for securing attachment and correct positioning of an unsymmetrical replaceable means for limiting the sinking of the ski pole into ground surfaces, such as a disc structure or a snow guard, in a desired direction relative to the shape of the ski pole.

[0101] In one embodiment, the diameter distorted section 9 may have a length along the ski pole of about 5-40 mm, more preferably about 10-30 mm, and most preferably about 15-25 mm. The diameter distorted section 9 may be placed about 10-40 mm from one end of the ski pole of the invention, more preferably about 20-30 mm from one end, and most preferably about 22-28 mm from one end of the ski pole of the invention.

[0102] A snow ring and a pole grip may be attached to the pole shaft such that the front part of the cross-section is directed forward in skiing direction.

[0103] The diameter distorted section of the above embodiments is primarily a feature which is designed to enhance friction when a stopper means is used to firmly fix a replaceable means for limiting the sinking of the ski pole into ground surfaces, such as a disc structure or a snow guard. The stopper, which is designed to be compatible with the replaceable means for limiting the sinking of the ski pole into ground surfaces, is aided in its stopper function by the enhanced friction of the diameter distorted section. Preferably, the diameter distorted section 9 may have a cross-sectional diameter less than the cross-sectional diameters of the sections immediately preceding and following said diameter distorted section. However, the diameter distorted section 9 may have a cross-sectional diameter which is greater than the cross-sectional diameters of the sections immediately preceding and following said diameter distorted section.

[0104] The feature for securing attachment may in a desired direction of such unsymmetrical means may be a slot placed diametrically across the circular cross-sectional end of the ski pole as shown in detail A, in FIG. 4

[0105] This slot may also be place slightly off center, or it may be placed off center to such a degree that the slot is a recess. The slot may preferably be about 1-10 mm deep, more preferably 2-8 mm deep, and most preferably 3-6 mm deep. However, it is contemplated that the slot of this embodiment may be replaced with other features for achieving the same result, such as one or more lips on the ski pole in the same area as the slot, or along the side of the ski pole in this area. It is also possible to achieve the same result with two or more slots.

[0106] In another embodiment of the ski pole of the invention, the ski pole may have incorporated means for enhancing the grip of the pole onto ground surfaces. This may be achieved by fitting the ski pole with a spike structure (not shown) in the end of the ski pole facing the ground when it is used for skiing or walking. The spike structure may be formed from any material which provides the material strength necessary for providing a grip on the desired surface.

[0107] FIG. 5 shows a table of the deformation test with a version of the triangular cross-sectional shaped shaft. Previous tests have shown that the triangular cross-sectional shape shaft has less span (less deformation) and higher breaking strength than a circular cross-section shape shaft.

[0108] Therefore, the test results shown in FIGS. 5 and 6 was performed on triangular cross-sectional shapes to compare it with the new four corners 6 cross-sectional shape (FIG. 6) according to the present invention.

[0109] In the following tests, the four corners cross-sectional shape of the present invention is also referred to as “Aero” or “Triac Aero” as a working title.

[0110] The test was performed by mounting a shaft between to supports with a distance of 800 mm between each other. The deformation test was performed using a pressure of 10-300 N at a center location on the shaft between the two supports. The deflection or span was measured for the tip and butt and entered into the table. Tests was performed on a front side, back side and side portions. One additional side test was performed to the Aero shape since it has four corners 6.

[0111] A summarized comparison table is shown in FIG. 7 where the triangular shape is named as: 2.5 v2 and 2.5 v4.

[0112] From the summarized table in FIG. 8, it is clear that the Aero shape has surprisingly less span both for the tip and for the butt for all sides. A column for the average measurement (for 3 sides) is also shown in the table, stating that the Aero shape has increased stiffness (i.e. less pan) than the comparable triangular cross-sectional shapes.

[0113] In the last columns in FIG. 8, the shafts where tested with a maximum load N for testing the braking strength in the transverse axis (perpendicular to the longitudinal direction) of the shafts. The test is also referred to as the “pull to limit” test. Side 1 is here referred to the front side (part) and side 3 referring to the back side (part). The results show that all sides of the four corner 6 shape (Aero) of the present invention, has increased breaking strength compared to the triangular cross-sectional shape.

[0114] It may therefore, with great probability, be concluded that the Aero shape cross-sectional shaft has less span and increased breaking strength compared to both the triangular cross-sectional shape and the circular (round) cross-sectional shape. In addition, as shown in the table of FIG. 8, the Aero shaped shaft has slightly lower weight than the triangular shape (we already know that the triangular shaped shaft is lighter in weight than the circular shaped). The weight is 55.39 g per meter, which is slightly lower than the weight of the triangular shape of: 55.99 g per meter and 56.66 per meter.

[0115] A test of Aerodynamics where also performed in a wind tunnel. Aerodynamics is a study of motion of air, particularly as interaction with the cross-sectional shape of the shaft. To measure the aerodynamics, a drag coefficient is often used. The drag coefficient is a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment, such as air or water. It is used in the drag equation in which a lower drag coefficient indicates the object will have less aerodynamic or hydrodynamic drag. The drag coefficient is always associated with a particular surface area.

[0116] FIG. 9 shows the test results by measuring the “coefficient of drag” x area (Dd * A). The test was performed to different shafts having different cross-sectional shapes such as: rounded, triangular, Aero new straight, Aero new curved.

[0117] Aero new straight shape was tested with the curved first portion in the forward direction (into the wind) and where both the second part and side parts are straight portions (“new straight”).

[0118] Aero new curved shape was tested with the curved first portion in the forward direction (into the wind) and where both the second part and side parts are slightly curved portions (“new curved”).

[0119] The shaft was tested at 30, 45, 75, 90 and 105 km/h. Relevant speed during skiing are up to 50 km/h, since higher speed is mostly during downhill skiing where the poles are held in a backward direction and are therefore not very relevant.

[0120] In addition, different angles of the shaft (angle of the wind in relation to the shaft) have been measured such as 0, 45, 90 and 180 degrees. Where the angles 0 and 45 are the most relevant angles since it is in the main moving direction of the skier (the 45 is directly from the side and 180 are directly from back).

[0121] The test results show that the curved first portion (circular arc) with a slightly rounded geometry of the second part and side portions, has better aerodynamic properties than the triangular shape at relevant speed and angles. The four corners 6 cross-section shape has consistently better aerodynamically properties compared to the circular cross-sectional shape.

[0122] The graphs in FIG. 10 a) show that for a wind of 0 degrees (wind directly from in front), and at speed of 30 km/h - 50 km/h, the “new curved” cross-sectional shape (dotted lines) has the lowest drag.

[0123] The same result is shown in the graphs in FIG. 10 b ), at wind angle of 45 degrees, where the “new curved” cross-sectional shape (dotted lines) has the lowest drag at the lower windspeed around 30 km/h.

[0124] Thus, one may conclude that the improved aerodynamics of the ski pole of the present invention, may most probably provide better pendulum characteristics for a skier during skiing.

[0125] To summarize, the shaft 1 for a ski pole of the present invention shows a remarkable and surprisingly combination of increased stiffness, rigidity and improved aerodynamics without increasing the weight of the shaft 1.