JP2006292059A - Chain adjusting bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve working efficiency in adjustment by increasing variation of a distance between a washer or the like and a shaft in comparison with a travel distance of a bolt obtained in prescribed rotation of the bolt, and to minimize the projection of the bolt to the external. <P>SOLUTION: This chain adjusting bolt is composed of: a bearing 1 mounted on a shaft of a gear, and having a shaft hole 5; a pedestal 2 kept into contact with a base frame such as a rear end of a bicycle on which the shaft of the gear is mounted; and a shoulder bolt 3 mounted between the bearing 1 and the pedestal 2. A peripheral wall of a large-diameter portion 12 and a peripheral wall of a small-diameter portion 11 of the shoulder bolt 3 are respectively provided with male screws of directions opposite to each other, and a locking portion for rotation 15 is formed on an end face of the large-diameter portion. The bearing 1 is provided with a female screw hole 7, the female screw hole 7 has a dimension to be engaged with the male screw of the small-diameter portion 11 of the shoulder bolt, the female screw hole 8 is penetrated through the pedestal, and the female screw hole has a dimension to be engaged with the male screw of the large-diameter portion 12 of the shoulder bolt 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chain pull used for adjusting the tension of a chain mounted on a bicycle, a motorcycle, or other drive device.

In chain pulling, a bolt is inserted into an adjuster mounted on a shaft of a gear around which the chain is wound, and the tension of the chain is adjusted by moving the adjuster back and forth with a nut member.
Japanese Utility Model Publication No. 5-26784

In the invention of the above patent document, a bolt hole is formed in a washer attached to the rear end portion of the chain stay, and a chain pulling bolt having a hole through which a gear shaft is inserted is attached to the bolt hole. The nut is screwed to the bolt, and the chain pulling bolt is moved in the axial direction by rotating the nut to adjust the position of the shaft of the gear.
Japanese Patent Laid-Open No. 7-187051

  In the invention of the above-mentioned patent document, an adjustment fitting is fitted into a swing arm through which a gear shaft is inserted, and a tip end side of an adjustment bolt through which the adjustment fitting is inserted is screwed into a screw hole formed in a rear end portion of the swing arm. In this configuration, the adjustment fitting is rotated in the axial direction by rotating the adjustment bolt, so that the position of the gear shaft can be adjusted.

  As described above, all the conventional chain pulls change the distance between the washer or the adjustment fitting and the shaft of the gear by rotation of a normal bolt. Therefore, the amount of movement of the bolt is the amount of change in the distance between the washer and the shaft as it is. Further, the base of the bolt inserted through the washer or the adjustment fitting protrudes to the outside.

  The present invention improves the adjustment work efficiency by increasing the amount of change in the distance between the washer and the shaft and the amount of movement of the bolt obtained when the bolt is rotated by a predetermined amount, and the bolt protrudes to the outside. The problem is to eliminate as much as possible.

The chain pull according to the present invention includes a bearing having a shaft hole mounted on a gear shaft, a pedestal that abuts a base frame on which the gear shaft is mounted, and a stepped bolt interposed between the bearing and the pedestal. Consists of.
The base frame is a chain stay in the case of a bicycle, and a bearing is attached to the rear end thereof. In the case of a motorcycle, the swing arm is the base frame.
The large-diameter portion peripheral wall and the small-diameter portion peripheral wall of the stepped bolt are formed with male threads opposite to each other, and a rotation locking portion is formed on the large-diameter end surface. The rotation locking portion is configured as a flat hexagonal hole for a hexagonal wrench, a cross or negative groove for a driver, and the like.
A female screw hole is formed in the bearing, and the female screw hole has a size to be engaged with a male screw of a small diameter portion of the stepped bolt. The pedestal is formed by penetrating a female screw hole, and the female screw hole is dimensioned to be screwed with a male screw of a large diameter portion of the stepped bolt.
The female screw hole of the pedestal needs to be a through hole in order to enable the rotation operation of the stepped bolt, but the female screw hole of the bearing need not be penetrated.
The bearing has a ring portion and a shaft portion having a female screw hole integrally formed as shown in the embodiment, and a shaft hole is formed on one side as a block of a flat rectangular parallelepiped, and a female screw hole is formed on the other side. It can also be set as the structure to form.
In the invention of claim 2, the bearing is configured by connecting a shaft portion having a female screw hole to a base portion having a shaft hole, and the outer diameter of the shaft portion is set to be a size that fits loosely in the female screw hole of the base. is there.

In the chain pulling of the present invention, the small diameter side of the stepped bolt is screwed into the female screw hole of the bearing, the large diameter side is screwed into the female screw hole of the pedestal, and the three members are integrated, and the shaft hole of the bearing is connected to the gear. The base is brought into contact with a base frame such as a rear end of a bicycle chain stay and held so as not to rotate.
Since the bearing and the pedestal have opposite screw directions, when the screw is rotated, the bearing and the pedestal move in a direction toward each other or in a direction away from each other. As a result, the rotation of the screw can be efficiently converted into movement of the distance between the bearing and the pedestal, and the work of adjusting the chain tension becomes efficient.
Further, according to the present invention, since the amount of change in the distance between the bearing and the pedestal becomes larger than the amount of movement of the screw as described above, the bolt is shorter than the conventional structure. As a result, the protrusion of the screw from the pedestal can be made as small as possible.
According to the invention of claim 2, since a part of the bearing is housed in the pedestal, the size is reduced.

  Examples will be described below.

A chain pull is constituted by a bearing 1, a base 2, and a stepped bolt 3 interposed between the bearing 1 and the base 2.
The bearing 1 has a shaft hole 5 to be attached to a rear wheel axle of a bicycle to which a gear around which a chain is wound is attached to a base portion 4, and a shaft portion 6 is integrally formed on one side of the base portion 4. The shaft portion 6 has a female screw hole 7 formed therein.
The pedestal 2 has a female screw hole 8 penetrating in the center thereof, and recesses 9 that are engaged with the rear end A of the chain stay of the bicycle are formed on both side back surfaces of the female screw hole 8. An annular wall 10 is formed on the surface as an extension of the female screw hole 8.
In the stepped bolt 3, the small diameter portion 11 is about five times as long as the large diameter portion 12, and a left screw (reverse screw) is provided on the peripheral wall of the large diameter portion, and a right screw (normal screw) is provided on the peripheral wall of the small diameter portion. It is formed. The female screw hole 7 of the bearing 1 is dimensioned to be screwed with the right-hand screw of the small-diameter portion, and the female screw hole 8 of the base 2 is screwed with the left-hand screw of the large-diameter portion. Further, the end face of the large diameter portion 12 is provided with a locking hole 15 with which a hexagon wrench is engaged.
In the above description, the outer diameter of the shaft portion 6 of the bearing 1 is dimensioned to fit loosely into the female screw hole 8 of the pedestal 2, and the total length of the stepped bolt 3 is the female screw hole 7 of the bearing 1 and the female screw hole 8 of the pedestal 2. It is shorter than the sum of the lengths (including the annular wall 10 portion).

As shown in FIG. 3, in this embodiment, the small diameter portion 11 of the stepped bolt 3 is screwed to the end of the female screw hole 7 of the bearing 1, and the large diameter portion 12 is the end of the female screw hole 8 of the base 2. Screw it to the extent that it protrudes slightly (about 1 mm) and attach it to the bicycle.
In the state where the bicycle 1 is mounted on the bicycle, the rotation of the bearing 1 is restricted by the rear wheel axle, and the rotation of the base 2 is restricted by the rear end A. Therefore, when the hexagon wrench is locked in the locking hole 15 of the stepped bolt 3 and the stepped bolt 3 is rotated in the left direction (counterclockwise), the bearing 1 and the pedestal 2 are moved away from each other. Therefore, the bearing 1 moves forward.
At this time, the small-diameter portion 11 of the stepped bolt 3 moves in the direction of coming out of the female screw hole 7 of the bearing 1, and the large-diameter portion 12 moves in the direction of coming out of the female screw hole 8 of the pedestal 2. It does not protrude to the front side. Moreover, since the bearing 1 and the base 2 each move away from each other, the amount of movement obtained by the rotation of the bolt is doubled.

  According to this invention, since the bearing and the pedestal are moved in the opposite directions by the rotation of the bolt, the amount of movement obtained by the rotation of the bolt is large, and the work efficiency of the chain tension adjustment work is improved. It has the availability of.

Exploded perspective view of the embodiment of the present invention Same perspective view Similarly, the front view of the initial state The front view of the forward state Same right side view Similarly front view of usage

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bearing 2 Base 3 Stepped bolt 4 Base part 5 Shaft hole 6 Shaft part 7 Female screw hole 8 Female screw hole 9 Recessed part 10 Annular wall 11 Small diameter part 12 Large diameter part 15 Locking hole

Claims (2)

A chain pull for adjusting the tension of the chain by moving the position of the shaft of the gear around which the chain is wound,
A bearing having a shaft hole to be mounted on the shaft of the gear, a pedestal that contacts a base frame to which the shaft of the gear is mounted, and a stepped bolt interposed between the bearing and the pedestal;
The large-diameter peripheral wall and the small-diameter peripheral wall of the stepped bolt are formed with mutually opposite male threads, and the large-diameter end face is formed with a locking part for rotation.
A female screw hole is formed in the bearing, and the female screw hole has a size to be screwed with a male screw of a small diameter portion of the stepped bolt,
A female screw hole is formed through the base, and the female screw hole is dimensioned to be screwed with a male screw of a large diameter portion of the stepped bolt.
Chain pull 2. The chain pulling according to claim 1, wherein the bearing is configured by connecting a shaft portion having a female screw hole to a base portion having a shaft hole, and an outer diameter of the shaft portion is set to be loosely fitted in the female screw hole of the base.

Images