JP3033646U - Bicycle crank - Google Patents

Abstract

(57) Abstract: To provide a bicycle crank which can easily assemble and disassemble a bicycle crank and a main shaft. SOLUTION: A bottom of a crank 1 is provided with a bedal, and a claw-shaped ream 2 at an upper end is connected to a gear disc group 3. A rectangular tapered hole 4 is installed in the center of the tapered hole 4, and a screw hole 8 having a predetermined depth and diameter is provided on one side of the tapered hole 4 for screwing the cover. In addition, a mouth opening 10 is prepared in order to insert a tool such as a wrench into the center of the cover 9 to operate it.
A recessed groove 11 of a predetermined size is also placed therein for receiving a part such as a screw 12. Further, the screw 12 tightens the crank 2 and the main shaft 5. On the other hand, when the screw 12 is loosened, the head 13 of the screw 12 separates the cover 9 from the cover 9 by the opposite acting force, which is useful for quick and easy disassembly.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a bicycle crank structure.

[0002]

[Prior art]

 As is well known, a conventional bicycle crank structure has a pedal (not shown) at the bottom of the crank, and a claw-shaped ream B at the upper end is connected to a gear disc group C, as shown in FIG. A rectangular hole D is installed in the center, and a groove E is provided outside the rectangular hole. The rectangular hole D and the concave groove E match the main shaft F and are tightened with the screw G. Currently, internal hexagon socket screws with washers are often used. Then, the crank A and the main shaft F are firmly joined.

[0003]

[Problems to be solved by the invention]

 However, since the rectangular hole D of the crank A and the joining portion H of the main shaft F are connected by a taper method, they are joined like a close contact. If the gear disc group C or the main shaft F is damaged, or disassembled or changed, it can be disassembled only with the special tool of the crank A. Not only are the costs of the tool high for the user or the bicycle dealer, but when the tool is scarce or lost, it can be completely out of work. It can be said that it is an inconvenience and a drawback of the conventional method.

In view of this, the inventor has been actively engaged in the development and improvement of the crank and related parts of a bicycle for many years and has been engaged in R & D. Solved. The main purpose of the present invention is to improve the conventional method of assembling and disassembling the crank and main shaft of a bicycle. To provide a general structure.

[0005]

[MEANS FOR SOLVING THE PROBLEMS] The present invention relates to a bicycle crank structure, and mainly has a structure in which a crank and a main shaft can be assembled and easily disassembled. The bottom of the crank has a bedal, and the claw-shaped ream at the top connects with the gear disc group. A rectangular taper hole is installed in the center, and a screw hole having a predetermined depth and diameter is provided on one side of the taper hole for screwing the cover.

[0006] Furthermore, an opening is intended to operate by inserting a tool such as a wrench in the center of the cover, and a recessed groove having a predetermined size is also arranged therein for inserting a part such as a screw. In addition, screws tighten the crank and main shaft. On the other hand, when the screw is loosened, the opposite action force of the screw head and the cover pulls the two apart, which is useful for quick and easy disassembly.

[0007]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The structure of the bicycle crank of the present invention is as shown in FIGS. As shown in FIG. 1, a claw-shaped ream 2 for connecting to a gear disc group 3 is provided at the upper end of a crank 1, and a rectangular tapered hole 4 is provided in the center thereof. The purpose of the tapered hole 4 is to join the joint 6 at one end of the main shaft 5, as shown in FIGS. That is, since the joint portion of the main shaft 5 is also processed into a corresponding rectangular taper shape, the main shaft 5 is inserted into the tapered hole 4 of the crank 1 so that the main shaft 5 can be closely attached.

On the other hand, on one side of the rectangular taper hole 4 in the center of the crank 1, there is a screw hole 8 having a predetermined depth and diameter for screwing the cover 9. Further, in order to insert and operate a tool such as a spanner in the center of the cover 9, a mouth opening 10 having a predetermined size is prepared, and the mouth opening 10 preferably matches the size of the hexagonal spanner. A recessed groove 11 having a predetermined size is also disposed therein for inserting a head 13 of a part such as a screw 12. The screw 12 ideally has an internal hexagonal hole with a washer as shown in FIG. 1, but other shapes may be used.

Of course, it is necessary that the size of the internal hexagonal hole of the screw 12 is smaller than the size of the opening 10 of the cover 9, and a hexagonal spanner can turn the screw 12 through the opening 10. For example, if the size of the opening 10 is 8 mm, the inner hexagonal hole size of the screw is 6 mm, and then the main shaft 5 is tightened. After all, the above-mentioned structural design of the crank 1 not only makes the hexagon spanner easy to buy at a general hardware store, but also has advantages such as easy carrying and a low price. On the other hand, in the conventional structure, disassembling tools were not sold at general hardware stores, so it was necessary to order from a specialized manufacturer, and the volume was large, inconvenient to carry, expensive, difficult to buy, etc. May have the disadvantages of. That is the economic benefit of tools.

When it is desired to disassemble the crank 1 and the main shaft 5, just insert a hexagon wrench from the opening 10, turn the screw 12, and loosen the screw 12 as shown in FIG. The opposite acting force that stretches the cover of the head 13 separates the crank 1 and the main shaft 5 from each other, which is useful for quick and easy disassembly.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention.

FIG. 2 is a sectional view after the embodiment of the present invention is combined with a main shaft.

FIG. 3 is an explanatory view for performing an operation of disassembling the embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conventional bicycle crank.

[Explanation of symbols]

 1 Crank 2 Claw Ream 3 Gearbox Group 4 Tapered Hole 5 Main Shaft 6 Joint 8 Thread Groove 9 Cover 10 Opening 11 Recessed Groove 12 Screw 13 Head

Claims (1)

[Utility model registration claims] 1. A claw-shaped ream for connecting to a gear disk group is arranged at the upper end of the crank, and has a rectangular tapered hole in the center thereof, and is joined to a joint portion at one end of the main shaft by the tapered hole, That is, since the joint portion of the main shaft is also processed into a corresponding rectangular taper shape, it is inserted into the tapered hole of the crank so as to be in close contact with it, and on the other hand, one side of the rectangular tapered hole in the center has a predetermined size for screwing the cover. There is a screw hole with a depth and diameter, and there is an opening for inserting a tool such as a wrench in the middle of the cover to operate.In order to insert parts such as screws, a recess of a predetermined size is inserted inside the opening. There is also an elliptical groove.Furthermore, the screw tightens the crank and the main shaft, and when the screw is loosened, the head of the screw protrudes from the cover and Bicycle crank, characterized in that it is possible to decompose both the adverse forces stretch.