JP3028252U - Front fork extension device for motorcycles - Google Patents

Abstract

(57) [PROBLEMS] To extend the length of a front fork of a motorcycle easily and at low cost, and to easily change the extension amount. SOLUTION: Inner tube 1 of front fork
A cylindrical insertion hole 13 into which the upper end of can be inserted,
An insertion amount limiting surface 14 for limiting the amount of insertion of the upper end of the inner tube 1 into the insertion hole 13 is formed in the insertion hole 13, and an extension extending from the insertion amount limiting surface 14 in the direction opposite to the insertion hole opening. It has an extension in which the part 15 is formed. When extending the front fork, extender 10
The upper end portion of the inner tube 1 is inserted into the insertion hole 13 of. Further, when the extension is desired, the extension amount adjusting tool 50 is put in the insertion hole 13.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a front fork extension device for extending a front fork of a motorcycle.

[0002]

[Prior art]

 As shown in FIG. 10, a front fork of a motorcycle generally includes an outer tube 2, an elastic material (not shown) such as a spring provided in the outer tube 2, and an outer tube 2. The inner tube 1 is mounted so as to be retractable. The lower end of the outer tube 2 is attached to the end of the front axle 4 that serves as the rotation axis of the front tire 3, and extends obliquely upward from the end of the front axle 4. The lower end of the inner tube 1 is inserted from the upper end of the outer tube 2. A triple tree 20 for connecting the inner tube 1 and the vehicle body frame is provided at the upper end of the inner tube 1.

By the way, the owner of a motorcycle, especially the owner of an American type motorcycle, often desires to extend the front fork. Therefore, in order to meet such a desire, conventionally, there is an extension device as shown in FIGS. 14 to 16.

Before explaining the extension device, the configuration of the triple tree 20 will be briefly described with reference to FIG. The triple tree 20 includes a neck shaft 40 that is inserted through an insertion hole of a head pipe of a vehicle body frame, a top bridge 30 that is attached to an upper end of the neck shaft 40, and a bottom bridge 21 that is attached to a lower end of the neck shaft 40. Have Both the bottom bridge 21 and the top bridge 30 are in the form of an isosceles triangular plate, and the neck shaft attachment portions 26 and 36 are formed near the portion corresponding to the apex thereof, and the bottom corners thereof are formed. Fork insertion holes 22 and 32 through which the upper end of the inner tube 1 can be inserted are formed in the vicinity of the corresponding portions.

The conventional extension device has an extension tool 5 having an outer diameter that is the same as the outer diameter of the hollow cylindrical inner tube 1. At the lower end of the extension tool 5, a female screw 1a formed along the inner peripheral surface of the upper end of the hollow cylindrical inner tube 1 is formed with a male screw 5a that can be screwed. At the upper end of the extension tool 5, a bolt head 5b for screwing the extension tool 5 into the female screw 1a of the inner tube 1 is formed.

When the front fork is extended by using the above extension device, first, the inner tube 1 is made movable relative to the bottom bridge 21 downward. Then, the inner tube 1 is pulled downward relative to the bottom bridge 21, and the male screw 5a of the extension 5 is screwed into the female screw 1a at the upper end of the inner tube 1. Next, the upper end of the extension tool 5 is passed through the fork insertion hole 32 of the top bridge 30, and the fork removal prevention screws 27 and 37 are screwed into the bridges 21 and 30, respectively, and the inner tube extended by the extension tool 5 is inserted. Fix 1 to triple tree 20. As a result, as shown in FIGS. 15 and 16, the front fork is extended by substantially the length of the extension tool 5.

[0007]

[Problems to be solved by the device]

 However, in such a conventional technique, when the female screw 1a is not formed on the upper end portion of the inner tube 1, the inner tube 1 having the female screw formed on the upper end portion must be prepared. It is very troublesome and costly. Furthermore, if the owner of the motorcycle extends the front fork with this extension tool 5 and then wants to extend it further, he / she must purchase an extension tool with a long length, which makes it flexible to change the extension amount. There is a problem that it does not exist.

The present invention has been made in view of such conventional problems, and the front hawk can be easily extended without increasing the cost, and the extension amount can be changed flexibly. It is intended to provide a front hawk extension device.

[0009]

[Means for Solving the Problems]

 A front fork extension device for achieving the above object is formed with a cylindrical insertion hole into which an upper end portion of a front fork can be inserted, and the upper end portion of the front fork is inserted into the insertion hole into the insertion hole. The present invention is characterized by having an extension tool in which an insertion amount limiting surface for limiting the insertion amount is formed, and an extension portion extending from the insertion amount limiting surface in a direction opposite to the insertion hole opening is formed.

Further, a front fork extension device for achieving the above-mentioned object has a lower end portion attached to both end portions of a front axle that serves as a rotation axis of a front tire of a motorcycle, and the front axle extends from the end portion of the front axle. A cylindrical front fork that extends diagonally upward, a neck shaft that is inserted through the insertion hole of the head pipe of the vehicle body frame, and a fork that is attached to the upper end of the neck shaft so that the upper end of the front fork can be inserted. Triple tree composed of a top bridge having an insertion hole and a bottom bridge attached to the lower end of the neck shaft and having a fork insertion hole through which the upper end of the front fork can be inserted A front fork extension device in which the A cylindrical insertion hole into which the portion can be inserted is formed, and an insertion amount limiting surface that limits the insertion amount of the upper end of the front fork into the insertion hole is formed in the insertion hole. An extended portion extending from the surface in the direction opposite to the insertion hole opening is formed, and a top bridge mounting portion extending from the extension portion in the direction opposite to the insertion hole opening and insertable into the fork insertion hole of the top bridge is formed. It is characterized by having an extended tool.

Further, still another front fork extension device for achieving the above-mentioned object, the lower end portions thereof are attached to both end portions of a front axle that serves as a rotation shaft of a front tire of a motorcycle, and A cylindrical front fork that extends diagonally upward from the end, and is attached to the neck shaft that is inserted into the insertion hole of the head pipe of the vehicle body frame and the upper end of the neck shaft so that the upper end of the front fork can be inserted. It has a top bridge having a fork insertion hole and a bottom bridge attached to the lower end of the neck shaft and having a fork insertion hole through which the upper end of the front fork can be inserted. A front fork extension device in which a triple tree is attached to the upper end of the front tree. A fork mounting portion having a cylindrical insertion hole into which the upper end of the fork can be inserted, and an extension extending from the fork mounting portion in a direction in which the insertion hole extends and in a direction opposite to the insertion hole opening. And a top bridge mounting portion that extends from the extension portion in a direction in which the insertion hole extends and in a direction opposite to the insertion hole opening and that can be inserted into the fork insertion hole of the top bridge. An insertion amount limiting surface that limits an insertion amount of the upper end portion of the front fork into the insertion hole is formed at an end portion of the fork mounting portion on the extension side of the insertion hole; The extension portion, the top bridge mounting portion, and the insertion hole each have a cylindrical shape about the same axis, and the fork mounting portion and the extension portion have the same outer diameter and the front portion. Top of fork The outer diameter of the top bridge mounting portion and the inner diameter of the insertion hole are substantially the same as the outer diameter of the upper portion of the front fork.

The front fork extension device described above may include the triple tree.

Further, the above front fork extension device may have front fork slip-out prevention means for suppressing the upper end portion of the front fork inserted into the insertion hole of the extension tool from slipping out of the insertion hole. desirable.

The front fork slip-off preventing means includes, for example, a front fork slip-out preventing screw that prevents the upper end of the front fork inserted into the insertion hole of the extension tool from slipping out of the insertion hole, and the extension. It is provided on both sides of the tightening notch, which is cut from the outer peripheral surface of the tool to the inner peripheral surface of the insertion hole and extends from the insertion hole opening toward the insertion amount limiting surface, and It may have a nut member and a front fork slip-off preventing screw that can be screwed into the female screw of each nut member.

Further, the front fork extension device described above includes an extension amount adjuster that can be inserted into the insertion hole of the extension tool and that can contact the upper end surface of the front fork and the insertion restriction surface of the insertion hole. May be.

It is preferable that the extension amount adjuster has a cylindrical shape and an outer diameter thereof is the same as an outer diameter of an upper end portion of the front fork.

[0017]

[Embodiment of device]

 A front hawk extension device for a motorcycle according to an embodiment of the present invention will be described below with reference to the drawings.

The front fork is, as described in “Prior Art” with reference to FIG. 10, the outer tube 2, the elastic material (not shown) such as a spring provided in the outer tube 2, and the outer tube 2. The inner tube 1 is attached to the outer tube 2 so as to be retractable. The lower end of the outer tube 2 is attached to the end of the front axle 4 that serves as the rotation axis of the front tire 3, and extends obliquely upward from the end of the front axle 4. The lower end of the inner tube 1 is inserted from the upper end of the outer tube 2. A triple tree 20 for connecting the inner tube 1 and the vehicle body frame is provided at the upper end of the inner tube 1. Here, for convenience of the following description, the outer diameter of the cylindrical inner tube 1 is set to 40 mm.

As shown in FIG. 1, the triple tree 20 provided on the upper end of the inner tube 1 is attached to the neck shaft 40 which is inserted into the insertion hole of the head pipe of the vehicle body frame and the upper end of the neck shaft 40. It has a top bridge 30 and a bottom bridge 21 attached to the lower end of the neck shaft 40. As shown in FIGS. 4 and 5, the bottom bridge 21 and the top bridge 30 each have an isosceles triangular plate shape, and the upper end of the inner tube 1 is near the portion corresponding to each bottom angle. Fork insertion holes 22 and 32 through which the parts can be inserted are formed. The inner diameter of each fork insertion hole 22, 32 is 41 mm, which is slightly larger than the outer diameter of the inner tube 1. Each of the bridges 21 and 30 is formed with notches 23 and 33 extending from the fork insertion holes 22 and 32 toward the hypotenuse of the bridge in the vicinity of the fork insertion holes 22 and 32, and cuts 23 from the hypotenuse of the bridge. , 33 are formed to form screw holes 24, 34. By screwing fork removal prevention screws 27 and 37 into the screw holes 24 and 34, the inner diameters of the fork insertion holes 22 and 32 are reduced, and the fork insertion holes 22 and 32 are inserted into the fork insertion holes 22 and 32. The inner tube 1 is tightened in the fork insertion holes 22 and 32 and cannot be pulled out from the holes 22 and 32. A neck shaft 40 is protrusively provided in the vicinity of the portion 26 corresponding to the apex of the bottom bridge 21. Further, near the portion corresponding to the bottom of the bottom bridge 21, headlight mounting screw holes 25, 25 for mounting the headlight are formed. A neck shaft mounting hole 36 into which the upper end portion of the neck shaft 40 can be inserted is formed near a portion corresponding to the apex of the top bridge 30. In addition, handle attaching screw holes 35, 35 for attaching a handle are formed in the vicinity of a portion corresponding to the bottom of the top bridge 30. As shown in FIGS. 1 and 5, a female screw 41 is formed on the upper end of the neck shaft 40. The neck shaft 40 is connected to the top bridge 30 by screwing a bolt 38 into the female screw 41 through the neck shaft mounting screw hole 36 of the top bridge 30.

As shown in FIG. 1, a front fork extension device according to an embodiment of the present invention includes an extension tool 10 for extending an inner tube 1 of a front fork, and an inner tube 1 from the extension tool 10. A fork removal prevention screw 19 is provided to prevent it from coming off.

As shown in FIGS. 1, 6 and 7, the extension tool 10 has a cylindrical main body 11 and nut members 18, 18 that can be said to be provided on the lower side circumference of the main body 11. . As shown in FIGS. 6 and 7, the main body 11 includes an inner tube mounting portion 12 having a cylindrical insertion hole 13 into which the upper end portion of the inner tube 1 can be inserted, and an inner tube mounting portion 12 It has an extension portion 15 extending upward and a top bridge mounting portion 16 which is provided at an upper end portion of the extension portion 15 and can be inserted into a fork insertion hole 32 of the top bridge 30. The vertical relationship described here is based on the positional relationship when the extension 10 is attached to the inner tube 1. The inner tube mounting portion 12, the insertion hole 13, the extension portion 15 and the top bridge mounting portion 16 formed in the inner tube mounting portion 12 are all cylindrical with the same axis as the center. The outer diameters of the inner tube mounting portion 12 and the extension portion 15 are the same, and are 50 mm, which is larger than the outer diameter of the inner tube 1. The outer diameter of the top bridge mounting portion 16 is 41 mm that can be inserted into the fork insertion hole 32 of the top bridge 30 and is slightly larger than the outer diameter of the inner tube 1. The inner diameter of the insertion hole 13 formed in the inner tube mounting portion 12 is 41 mm, which is slightly larger than the outer diameter of the inner tube 1. The length of the inner tube mounting portion 12 and the extension portion 15 is slightly smaller than the distance between the lower surface of the top bridge 30 and the upper surface of the bottom bridge 21 so that these portions can be accommodated between the top bridge 30 and the bottom bridge 21. short. Further, the length of the top bridge mounting portion 16 is slightly longer than the length of the fork insertion hole 32 of the top bridge 30. The extension portion 15 is formed with a hole 13a which is continuous with the insertion hole 13 of the inner tube mounting portion 12 and has an inner diameter smaller than that of the insertion hole 13. The step surface at the boundary between the hole 13a and the insertion hole 13 forms an insertion amount limiting surface 14. In the vicinity of the insertion hole opening of the main body 11, a tightening notch 17 is formed that is cut from the outer peripheral surface of the main body to the inner peripheral surface of the insertion hole 13 and extends from the insertion hole opening toward the insertion amount limiting surface 14. Nut members 18, 18 are provided on the side circumference of the main body 11 and on both sides of the fastening notch 17 as the center. The center axes of the two nut members 18 and 18 are located on the same straight line so that one fork removal preventing screw 19 can be screwed into these female screws.

Next, the procedure for extending the front fork using the above extension device will be described. First, the fork removal preventing screws 27, 37 screwed into the screw holes 24 of the bottom bridge 21 and the screw holes 34 of the top bridge 30 are removed, and the inner tubes 1, 1 are relatively attached to the triple tree 20. Try to pull it down. Next, the inner tubes 1 and 1 are pulled downward relative to the triple tree 20 until the upper end surface of the inner tube 1 is located below the upper end surface of the bottom bridge 21. Next, the top bridge mounting portions 16 and 16 of the two extension tools 10 and 10 are respectively inserted into the two fork insertion holes 32 and 32 of the top bridge 30 to extend between the top bridge 30 and the bottom bridge 21. Position the tools 10, 10. Subsequently, the inner tubes 1, 1 are pulled upward relative to the triple tree 20, and the upper end portions of the inner tubes 1, 1 are inserted into the insertion holes 13, 1 of the extension tools 10, 10. Then, when the upper end surface of the inner tube 1 comes into contact with the insertion amount limiting surface 14 of the extension tool 10, the fork removal prevention screw 19 is screwed into the nut member 18 of the extension tool 10 to insert the insertion hole 13 of the extension tool 10. The inner diameter is made small to prevent the inner tube 1 from coming off from the insertion hole 13 of the extension tool 10. Finally, the fork removal preventing screws 27 and 37 are screwed into the screw holes 24 and 34 of the bridges 21 and 30, respectively, to reduce the inner diameters of the fork insertion holes 22 and 32 of the bridges 21 and 30 to reduce the fork. It prevents the inner tube 1 extended by the extension 10 from the insertion holes 22 and 32 from coming off. As a result, as shown in FIGS. 2, 3 and 11, the front fork is extended by the length of the extension portion 15 of the extension tool 10 and the top bridge mounting portion 16.

As described above, in the front fork extension device of this embodiment, the extension tool 10 is attached to the inner tube 1 by inserting the upper end portion of the inner tube 1 into the insertion hole 13 of the extension tool 10. Therefore, unlike the prior art, when there is no female screw at the upper end of the inner tube 1, there is no need to bother to form the female screw.

Further, in this embodiment, after extending the front fork with the extension tool 10, if it is desired to further extend the front fork, as shown in FIG. 12, it can be inserted into the insertion hole 13 of the extension tool 10. If the cylindrical extension amount adjuster 50 is prepared, the length of the front fork can be easily extended without preparing the extender longer than the original extender 10. The cylindrical extension amount adjusting tool 50 can be inserted into the insertion hole 13 of the extension tool 10 and has an outer diameter that can be contacted with the upper end surface of the inner tube 1 and the insertion amount limiting surface 14 of the insertion hole 13. It is 40 mm, which is the same as the outer diameter of the tube 1.

When the front fork is further extended by using the extension amount adjuster 50, the extension amount adjuster 50 is previously placed in the insertion hole 13 of the extender 10, and the front part described above is then used. The work may be performed in the same procedure as the fork extension work. As a result, as shown in FIG. 13, the front fork is further extended by the length of the extension amount adjuster 50.

By the way, a person who desires to extend the front fork desires to reduce the caster angle α ₂ from the initial angle α ₁ along with the extension of the front fork, as shown in FIGS. 8 and 9. Often. The caster angle α can be changed by changing the angle β formed by the head pipe 61 of the vehicle body frame 60 and the front fork. Therefore, the angle of the neck shaft 40 inserted into the head pipe 61 of the vehicle body frame 60 is set with respect to the line segment connecting the fork insertion hole 32 of the top bridge 30 and the hawk insertion hole 22 of the bottom bridge 21. It is sufficient to prepare the changed triple tree 20a.

Therefore, for those who desire to reduce the caster angle α with the extension of the front fork, in addition to the extension tool 10 described above, a triple tree in which the angle of the neck shaft 40 is changed. The device including 20a may be sold as an extension device.

In the above embodiment, the outer diameter of the inner tube 1 is described as 40 mm, but this is only for explaining the dimensional relationship with the inner diameter of the insertion hole 13 of the extension tool 10, It goes without saying that the present invention is not limited to this size.

[0029]

[Effect of device]

 According to the present invention, the front fork is extended by inserting the upper end of the front fork into the insertion hole of the extension, so that it is necessary to form a screw on the upper end of the front fork to attach the extension. The front fork can be extended easily and at low cost.

Further, by inserting the extension amount adjusting member into the insertion hole of the extension tool, the front fork can be further extended, so that the extension amount can be easily changed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a front fork extension device and a triple tree according to an embodiment of the present invention.

FIG. 2 is a perspective view of an upper end portion of the front fork in which the front fork extension device according to the embodiment of the present invention is incorporated.

FIG. 3 is a front view of the upper end of the front fork in a state in which the front fork extension device according to the embodiment of the present invention is incorporated.

FIG. 4 is a top view of a top bridge.

FIG. 5 is a top view of a bottom bridge.

FIG. 6 is a vertical cross-sectional view of an extension tool according to an embodiment of the present invention.

FIG. 7 is a sectional view taken along line VII-VII in FIG. 6;

FIG. 8 is a side view around the front fork before the extension device is incorporated.

FIG. 9 is a side view around the front fork after the front fork extension device according to the embodiment of the present invention is assembled.

FIG. 10 is a perspective view around the front fork before the extension device is incorporated.

FIG. 11 is a perspective view around the front fork after the front fork extension device as one embodiment according to the present invention is assembled.

FIG. 12 is an exploded perspective view of a front fork extension device and a triple tree according to another embodiment of the present invention.

FIG. 13 is a perspective view of an upper end portion of a front fork in which a front fork extension device according to another embodiment of the present invention is incorporated.

FIG. 14 is a developed perspective view of a conventional front fork extension device and a triple tree.

FIG. 15 is a perspective view of an upper end portion of a front fork in a state where a conventional front fork extension device is incorporated.

FIG. 16 is a perspective view around the front fork after the installation of the conventional front fork extension device.

[Explanation of symbols]

1 ... Inner tube, 2 ... Outer tube, 3 ... Front tire, 4 ... Front axle, 10 ... Extender,
11 ... Main body, 12 ... Inner tube mounting part (fork mounting part), 13 ... Insertion hole, 14 ... Insertion amount limiting surface, 15 ...
Extension part, 16 ... Top bridge mounting part, 17 ... Tightening notch, 18 ... Nut member, 19 ... Fork removal prevention screw, 20 ... Triple tree, 21 ... Bottom bridge, 2
2, 32 ... Fork insertion hole, 30 ... Top bridge, 4
0 ... Neck shaft, 50 ... Extension adjustment tool, 60 ... Body frame, 61 ... Head pipe.

Claims (8)

[Scope of utility model registration request] 1. A device for extending a cylindrical front fork, the lower end of which is attached to both ends of a front axle that serves as a rotation axis of a front tire of a motorcycle, and which extends obliquely upward from the end of the front axle. In, a cylindrical insertion hole into which the upper end of the front fork can be inserted is formed, and an insertion amount limiting surface that limits the amount of insertion of the upper end of the front fork into the insertion hole is formed in the insertion hole. And a front fork extension device having an extension formed with an extension extending from the insertion amount limiting surface in a direction opposite to the insertion hole opening. 2. A cylindrical front fork having a lower end attached to both ends of a front axle, which serves as a rotary shaft of a front tire of a motorcycle, and extending obliquely upward from the end of the front axle. A neck shaft that is inserted through the insertion hole of the head pipe of the frame, a top bridge that is attached to the upper end of the neck shaft and has a fork insertion hole through which the upper end of the front fork can be inserted, and the lower end of the neck shaft. And a bottom bridge having a fork insertion hole through which the upper end of the front fork can be inserted, the triple fork being attached to the upper end of the front fork extension device. A cylindrical insertion hole is formed into which the upper end of the insert hole can be inserted. An insertion amount limiting surface that limits the amount of insertion of the upper end of the tok fork into the insertion hole is formed, and an extension portion extending from the insertion amount limiting surface in a direction opposite to the insertion hole opening is formed, and from the extension portion, A front fork extension device having an extension tool that extends in a direction opposite to an insertion hole and has a top bridge mounting portion that can be inserted into a fork insertion hole of the top bridge. 3. A cylindrical front fork having a lower end portion attached to both ends of a front axle, which serves as a rotation axis of a front tire of a motorcycle, and extending obliquely upward from the end portion of the front axle. A neck shaft that is inserted through the insertion hole of the head pipe of the frame, a top bridge that is attached to the upper end of the neck shaft and has a fork insertion hole through which the upper end of the front fork can be inserted, and the lower end of the neck shaft. And a bottom bridge having a fork insertion hole through which the upper end of the front fork can be inserted, the triple fork being attached to the upper end of the front fork extension device. A fork mounting portion having a cylindrical insertion hole into which the upper end portion of can be inserted, An extension portion extending from the fork mounting portion in a direction in which the insertion hole extends and in a direction opposite to the insertion hole opening, and an extension portion in the direction in which the insertion hole extends and in a direction opposite to the insertion hole opening. An extension tool having a top bridge mounting portion that can be inserted into the fork insertion hole of the top bridge, and an end portion of the insertion hole of the fork mounting portion on the extension portion side is provided with a front fork of the front fork. An insertion amount limiting surface for limiting the insertion amount of the upper end portion into the insertion hole is formed, and the fork mounting portion, the extension portion, the top bridge mounting portion, and the insertion hole are all cylinders about the same axis. The fork mounting portion and the extension portion have the same outer diameter and are larger than the outer diameter of the upper end portion of the front fork, the outer diameter of the top bridge mounting portion and the inner diameter of the insertion hole. Is substantially Front fork extension and wherein the that is the same as the outer diameter of the upper end portion of the front fork. 4. The front fork extension device according to claim 2, further comprising the triple tree. 5. The front fork extension device according to claim 1, 2, 3 or 4, wherein an upper end portion of the front fork inserted into the insertion hole of the extension tool is prevented from coming out of the insertion hole. A front fork extension device having a front fork removal preventing means. 6. The front fork extension device according to claim 1, 2, 3 or 4, wherein an upper end portion of the front fork inserted into the insertion hole of the extension tool is prevented from coming out of the insertion hole. A front fork removal prevention screw is provided, and the extension tool has a notch for tightening that is cut from the outer circumferential surface of the extension tool to the inner circumferential surface of the insertion hole and extends from the insertion hole opening toward the insertion amount limiting surface. Is formed,
A front fork extension device, characterized in that a nut member is formed on each of both sides of the tightening notch, each of which has a female screw to which one front fork removal preventing screw can be screwed. 7. The front fork extension device according to claim 1, 2, 3, 4, 5 or 6, wherein the front fork extension device is insertable into an insertion hole of the extension tool, and an insertion amount of the upper end surface of the front fork and the insertion hole. A front fork extension device comprising an extension amount adjuster capable of contacting a limiting surface. 8. The front fork extension device according to claim 7, wherein the extension amount adjusting tool has a cylindrical shape, and an outer diameter thereof is the same as an outer diameter of an upper end portion of the front fork. Front fork extension device.