JPS586792Y2 - bicycle gear crank - Google Patents

Description

[Detailed description of the invention] This invention is a gear crank for a bicycle, more specifically, a gear crank that is provided with at least one gear on a fixed member protruding toward the outer circumference of the crank body, and a protector provided on the outside of the gear. Regarding the crank.

Conventionally, to fix the bicycle gear to a fixed member,
A step is formed in the fixing member, and a through hole is formed in the member and the gear respectively, and a bolt is inserted between the two through holes with the gear locked in the step, and the bolt is inserted. By screwing a nut into the insertion end of the gear, the gear is fixed to the fixing member.

Furthermore, a protector is generally provided on the outer side of the gear to prevent clothing from coming into contact with the gear, but the protector protects the outermost gear from bolts and nuts. It is intended to be installed through the

Therefore, according to the above gear crank, the number of parts for fixing the gear and the protector is extremely large, which not only makes it troublesome to attach both, but also increases the assembly cost.

The present invention has been devised in view of the above points, and is characterized in that both the protector and the gear are simultaneously fixed to a fixing member using the protector, and the number of parts required to fix both is reduced. This reduces the assembly and processing costs.

Next, details of the present invention will be explained based on embodiments of the drawings.

In the figure, 1 is a gear crank body of a gear crank that is attached to the side of a front bicycle hub A. A crank arm 2 with a pedal (not shown) at the tip is integrally formed on the outer periphery, and the crank body 1 Five fixing members 3 are integrally formed radially at equal intervals in the inner and outer circumferential direction of the arm 2.

4.5 are gears with different outer diameters, which are to be fixed to the fixing member 3, and 6 is a protector provided on the outer side of the gears 4 and 5 with a diameter larger than that of the large-diameter gear 4. .

According to the present invention, in the gear crank described above, the gears 4, 5 and the protector 6 are fixed in the following manner.

That is, five cylindrical bodies 7 are integrally formed inside the protector 6 in the radial direction at equal intervals so as to face inward in the axial direction, and screw holes 8 are provided inside the cylindrical bodies 7.

This cylindrical body 7 is formed integrally with the protector 6 by forging or casting.

Further, the outer circumferential portion of the fixing member 3 is made thin so that the thin wall portion 3a
At the same time, through holes 9, 10, 11 for inserting the cylinder 6 into the thin part 3a of the fixing member 3 and the gears 4, 5 are formed.
are formed respectively.

Then, the gears 4 and 5 are applied to both sides of the fixing member 3, and in this state, each cylinder 7 of the protector 6 is inserted into the through holes 9, 10, 11 of the protector 6 from the outside of the gear 4. At the same time, a bolt 12 having a head 12a is screwed into the screw hole 8 of the cylindrical body 7 from the inside thereof, and this bolt head 1
2a and the inner wall surface of the protector 6, both the gears 4
,5.

Both gears 4.5 and the protector 6 are fixed to the fixing member 3 by applying pressure to the thin portion 3a of the fixing member 3.

In addition, in the above, the screw hole 8 is formed inside the cylindrical body 7, and the extraction hole 8 is
The gears 4, 5 and the protector 6 were supposed to be fixed to the fixing member 3 by screwing the bolts 12 into the protector 6, but the present invention has a method of fixing the protector 6 to the outer periphery of the cylindrical body 7 of the protector 6, as shown in FIG. The gears 4 and 5 and the protector 6 may be fixed to the fixing member 3 by forming a threaded portion 13 and screwing a nut 14 into the tip of the cylindrical body 7.

Furthermore, although the outer side of the protector of the cylindrical body 7 is shown open in each drawing, the outer side may be closed, and in this case, the aforementioned bolts 12 and the like are not visible from the outside, and the appearance of the gear crank is improved. becomes.

Furthermore, the present invention can also be used when attaching one gear to the fixing member 3, or when attaching three or more gears.

Further, the fixing member 3 is not limited to the above-mentioned shape, but may also have a disk shape, for example.

As explained above, in the present invention, a plurality of cylindrical bodies are provided protruding from a protector provided on the outside of a gear, each of these cylindrical bodies is inserted between the gear and a fixed member, and a screw thread is attached to the insertion end of each cylindrical body. Since both the protector and the gear are configured to be fixed to the fixing member at the same time by screwing them together, the number of parts required to fix both can be significantly reduced compared to the conventional method, and therefore the installation operation for both can be reduced. This makes it possible to reduce assembly processing costs and provide gear cranks at low cost.

[Brief explanation of the drawing]

FIG. 1 is a front view of a gear crank according to the present invention, FIG. 2 is a partially cutaway enlarged side view thereof, and FIG. 3 is a drawing showing another embodiment. 1...Crank body, 3...Fixing member, 4, 5...Gear, 6...Protector, 7...Cylinder body, 8゜13...Threaded part, 9,10,11...Through hole, 12゜14...
...Screw body.

Claims (1)

[Scope of utility model registration request] In a bicycle gear crank, in which at least one gear is provided on a fixing member protruding toward the outer circumference of a crank body, and a protector is provided on the outside of the gear, the protector includes a plurality of cylindrical bodies each having a threaded portion. In addition to protruding inward in the axial direction, a through hole is formed in each of the cylindrical bodies in the gear and the fixing member, and when the gear and the fixing member are overlapped, a hole is formed between the through holes. A gear crank for a bicycle, characterized in that the gear is fixed to a fixing member together with a protector by inserting each of the cylindrical bodies and screwing a screw body to an end of the winding cylindrical body.