JPH076092U - Boom for sailboard - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a boom for a sailboard that has strength, operability, and workability. A cross-sectional shape of at least the gripping portion E of the boom pipe 10 is formed to be substantially flat with its long axis substantially matching the plane formed by the boom.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sailboard boom, and more particularly, to improving the strength and operability of a sailboard boom.

[0002]

[Prior art]

 Boom pipes used for board sailing (windsurfing) are required to have a certain strength for various reasons. That is, the outer shape of the boom 100 under no load shown by the solid line in FIG. 9 changes to the shape shown by the broken line by the force received by the sail 110. The length in the direction is shortened by the dimension A. In this case, since the sail 110 draws a slack curve 110 'that deviates from the ideal curve, the desired propulsive force cannot be obtained, which is extremely disadvantageous in races and the like. Further, when it is wound in a wave or the like, when a force is applied from the B direction, the largest bending moment is generated in the curved portion C, so that this portion C may be damaged.

On the other hand, with the recent spread of marine sports, the number of board sailing enthusiasts is rapidly increasing not only for men but also for women. Generally, beginners, especially women, have low grip strength, so holding the boom pipe for a long time causes fatigue. Conventionally, the outer diameter of the boom pipe has generally been 32 mm, but as shown in FIG. 10, since the angle D of the finger joint is relatively large with this outer diameter, a large grip force is required. Therefore, it is difficult to stably hold the boom pipe.

[0004]

[Problems to be solved by the device]

 Therefore, recently, booms with boom pipes having an outer diameter of 30 mm or 28 mm have been widely used. However, although it is improved in terms of operability (easiness of gripping), it has a problem in terms of strength.

In order to solve this problem, it is conceivable to reduce the outer diameter of the boom pipe and increase the wall thickness of the boom pipe, but since the weight of the boom pipe increases, the operation becomes difficult. There is. Further, as shown in FIG. 11, an attempt has been made to form the cross section of the boom pipe into a substantially octagonal shape. However, although it has been improved in terms of ease of gripping, it is still difficult to grip for a long time because the outer diameter is almost the same as the original pipe. There is also the problem that the process for obtaining this cross-sectional shape is complicated. Therefore, an object of the present invention is to provide a novel sailboard boom that has strength, operability, and workability.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the sailboard boom of the present invention has a boom pipe having a circular cross section in which at least the gripping portion has a substantially flat cross-section with its major axis substantially matching the plane formed by the boom. It is a feature. Here, “substantially flat” is understood to include all crushed shapes such as so-called oval, elliptical, and oval shapes obtained by applying forces from two directions facing a circular cross section.

[0007]

[Action]

 By making the cross section flat, it is possible to obtain strength that can withstand the bending moment. Moreover, since the radius of the tip of the long axis is smaller than the radius before machining, operability, that is, grasping for a long time is easy.

[0008]

【Example】

 Hereinafter, a preferred embodiment of a boom for a sailboard according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view showing an embodiment of a boom for a sailboard according to the present invention. FIG. 2 is an enlarged sectional view taken along the line II-II in FIG. FIG. 3 is an enlarged sectional view taken along line III-III in FIG. FIG. 4 is a view showing a state in which the grip portion of the boom of FIG. 1 is gripped.

In FIG. 1, a boom 2 includes a pair of boom pipes 10 and 10, a boom jaw 12 that fixes the boom pipe 10 on a mast (not shown) side, a boom end 14, and a boom as in the conventional art. An extension pipe 16 that connects the pipes 10 and 10 and the boom end 14 is formed. The difference from the conventional boom is the cross-sectional shape of the grip E. As shown in FIG. 2, the cross section of the boom pipe 10 in the grip portion E is formed into a so-called ellipse having a major axis that coincides with the plane formed by the boom 2. The processing for forming this shape is performed by pressing a boom pipe having a circular cross section with a die from a direction perpendicular to the paper surface in FIG. 1 and the opposite direction. Therefore, the processing of this cross section is very easy. The grip portion E of the boom pipe 10 thus formed has a smaller radius on the side facing the inside of the boom 2 than that of the boom pipe 10 before processing. Therefore, when a finger is put around the grip portion E, as shown in FIG. 4, the angle H of the finger joint becomes smaller than in the conventional case, so that the grip force is increased and the finger is less fatigued.

The portions other than the grip portion E, that is, the portions F and G may be formed in the same shape as the grip portion E, but the cross-sectional shape of these portions remains the circular pipe shape before processing. This has the following advantages. That is, first, the conventional boom jaws 12, boom ends 14, and extension pipes 16 can be used as they are, so that no additional cost is generated. Secondly, since sand easily enters the part where the extension pipe 16 is inserted, it is necessary to remove the sand by removing the extension pipe 16 by rotating the extension pipe 16 and the other parts in opposite directions. is there. Therefore, if the cross section is left circular, it can be easily removed.

The preferred embodiment of the boom of the present invention has been described above, but the present invention is not limited to the above-mentioned embodiment, and various modifications and changes can be made as necessary. For example, the cross-sectional shape of the grip portion E may be not only a so-called ellipse but also an ellipse shown in FIG. Further, it may have an oval shape shown in FIG. Further, it may have the shape shown in FIG. 7. In short, any shape can be used as long as the radius of the portion facing the inside of the boom is relatively small so that the grip can be maintained easily and the large bending moment generated in the boom pipe can be resisted. The major axis of the grip portion E does not necessarily have to be aligned with the plane formed by the boom. For example, the angle J formed by the plane L formed by the boom and the major axis may be set to 30 degrees or less in consideration of ease of gripping and strength. This range is called "substantially coincident".

[0012]

[Effect of device]

 According to the present invention, a sailboard boom having strength, operability, and workability can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a sailboard boom of the present invention.

FIG. 2 is an enlarged sectional view taken along the line II-II in FIG.

FIG. 3 is an enlarged cross-sectional view taken along the line III-III in FIG.

FIG. 4 is a diagram showing a state in which a grip portion of the boom shown in FIG. 1 is gripped.

5 to 8 are views showing another embodiment of the present invention.

9 to 11 are views showing a conventional example.

[Explanation of symbols]

 2 Sail board boom 10 Boom pipe E Grip

Claims (1)

[Scope of utility model registration request] 1. A boom for a sailboard, characterized in that at least a holding portion of a boom pipe having a circular cross section is formed to have a substantially flat cross-sectional shape whose major axis substantially matches a plane formed by the boom.