JPS6225991Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bicycle gear shift lever, and more specifically, the present invention is designed to prevent the frictional resistance that should be applied to the rotation of the lever from decreasing as the period of use increases. This article relates to an improved bicycle gear shift lever.

Bicycle transmissions are constructed so that they can be operated by rotating an operating lever attached to the frame tube of the bicycle, etc., and the connection between this operating lever and the transmission is generally an outer wire that is inserted through this. They are connected by a double wire consisting of a double inner wire. When you turn the lever,
Relative motion in the axial direction is applied between the inner wire and the outer wire, and the transmission is operated by this relative motion. In the case of a rear transmission, the transmission includes a base member attached to the rear end plate of the bicycle, a pair of link members that extend parallel to each other from the base member and are swingable with respect to the base member, and these link members. It has a so-called parallelogram pantograph mechanism consisting of a movable member pivotally attached to the tip and positioned opposite to the base member. The ends of the double wires are connected so that the length of the diagonal of the parallelogram of the pantograph mechanism can be changed. When the pantograph mechanism is deformed by rotating the operating lever,
A tensioner attached to the movable member moves in the axial direction of the multi-stage freewheel while maintaining a parallel relationship to each sprocket of the multi-stage freewheel. This allows the chain to be replaced with the desired sprocket.

By the way, when using a so-called pull-type inner wire that is highly flexible and cannot transmit pushing force as the inner wire constituting the double wire, the transmission deforms and biases the pantograph mechanism in one direction. Use one with a built-in return spring. Therefore, the inner wire is always pulled toward the transmission by the return spring. When the operating lever is rotated in a direction that pulls the inner wire toward the lever, the pantograph mechanism overcomes the elasticity of the return spring and deforms, while when the operating lever is rotated in the opposite direction,
The pantograph mechanism is deformed back within a range allowed by the return rotation of the operating lever by the elasticity of a return spring built into the pantograph mechanism itself.

As mentioned above, when operating a transmission incorporating a return spring via a double wire using a pull-type inner wire, the operation lever must be rotated in order to stop it at a fixed rotation position. It is necessary to provide sufficient resistance to the movement of the return spring to counteract the elasticity of the return spring. Conventionally, as a frictional resistance imparting means for this purpose, a friction imparting member is unrotatably fitted into the lever shaft into which the base of the lever body is rotatably inserted.
Further, a structure is known in which the friction imparting member is brought into pressure contact with the base of the lever body by a presser screw screwed into the shaft end of the lever shaft. Since the friction-applying member, which cannot rotate with respect to the lever shaft, is brought into pressure contact with the base of the lever body, sliding frictional resistance is generated on the contact surface between the base of the lever body and the friction-applying member.

In order to make the friction imparting member non-rotatable with respect to the lever shaft, generally an irregularly shaped portion having an oval cross section, for example, is formed at the end of the lever shaft, and a through hole of the same shape is also bored in the friction imparting member. , these are generally constructed by fitting them together. However, since there is inevitably a slight gap between the irregularly shaped part of the lever shaft and the hole in the friction imparting member, if the lever is repeatedly rotated, the lever will not rotate relative to the lever shaft in principle. The friction-applying member also rotates with the lever body slightly by the amount of play allowed by the slight clearance mentioned above, and as a result, the presser screw for pressing the friction-applying member gradually loosens, and eventually the lever body of the friction-applying member A problem exists in that the pressing force against the base is insufficient.
To solve this problem, by forcibly pressing the friction-applying member in a direction perpendicular to the lever shaft, the slight gap between the irregularly shaped end of the lever shaft and the hole in the friction-applying member is eliminated, and the lever Japanese Utility Model Application No. 57-128589 discloses a structure of a speed change operating lever in which a friction imparting member fitted onto the shaft is prevented from rotating even slightly. However, with this device, the pressure to press the friction imparting member in the direction orthogonal to the lever shaft must be supported by a retainer screw screwed into the shaft end of the lever shaft, which imposes an unreasonable bending load on the retainer screw. In addition, the friction imparting member is not effectively pressed in the direction perpendicular to the axis, and the rotational frictional resistance of the lever body is completely prevented from decreasing over time. I couldn't do it.

This idea was devised in view of the above circumstances.
It is an object of the present invention to provide a bicycle speed change operation lever having a structure capable of keeping rotational frictional resistance to be applied to a lever body constant for a long period of time.

In order to achieve this purpose, the present invention takes the following technical measures. That is, a split groove is provided in the distal end spiral portion of the lever shaft that rotatably supports the lever body, and a friction imparting member having a pinched portion that can fit into the split groove is provided. The friction imparting member is fitted to the lever shaft while being fitted into the split groove, and the friction imparting member is pressed against the lever body by screwing a nut to the helical shaft portion of the lever shaft. .

By doing so, the following effects can be obtained. In other words, when screwing a nut onto the threaded part of the lever shaft, the width of the split groove is forcibly narrowed due to the slope effect of the thread, and the part to be clamped that is fitted into this split groove is It is strongly clamped inside. Therefore, there is no gap between the split groove and the clamped part, and there is no room for co-rotation due to the reciprocating rotation of the lever of the friction imparting member that induces loosening of the nut. It disappears.
Further, if an elastic material such as resin is used as the friction imparting member, the above effect is further enhanced.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

The drawing shows an example in which the present invention is applied to a bicycle gear shift operation lever that is equipped with a so-called click mechanism and configured to lock the lever at a predetermined rotational position so that accurate gear shifting operations can be performed quickly. . Since the lever of this embodiment is equipped with a click mechanism, it seems unnecessary to provide a separate means for applying friction to stop the lever at a predetermined rotational position against the elasticity of the return spring of the transmission. However, the click mechanism in this embodiment is a special click mechanism that is configured to further reciprocate by a slight angle at each locking position of the lever body to finely adjust the transmission. It becomes necessary to stop the lever main body at an arbitrary position within the range of a certain angle in which it can move using the above-mentioned friction applying means.

Reference numeral 1 denotes a lever mounting base, which is fixed to the bicycle frame 2 using a band 3 or the like. Reference numeral 4 denotes a cover fixed to an appropriate part of the lever mount 1, and the number of gears is displayed on the top surface of the cover in conjunction with the rotational movement of the lever. The structure for displaying the number of gears is not an important part of the present invention, so its explanation will be omitted.

A vertical flat part 1a is formed on the side surface of the lever stand 1, and a lever shaft 5 projects laterally from this flat part. As shown in the illustrated example, this lever shaft 5 is constructed by protruding a bolt-shaped lever shaft from the back side of a shaft support hole 6 drilled in the flat portion 1a, or is fixed to the flat portion 1a by direct welding or the like. It can also be configured.

Reference numeral 7 denotes a click plate, which, as clearly shown in Fig. 3, has a substantially sector-like shape with click holes 7a, 7b, etc. arranged in an arc shape, the number of which corresponds to the number of variable stages of the transmission. 8 to the lever shaft 5, and by engaging the notch 9 provided at the appropriate part with the protrusion 10 provided on the flat part of the lever base 1, the lever shaft 5 is assembled. It is designed not to rotate relative to the

The lever main body 11 has a base portion 11a having a support hole 12 in the center, and a rod portion 11b extending outward in the radial direction of the lever shaft from the base portion 11a, and a grip at the tip of the rod portion 11b. 13 is installed. Further, a holding hole 15 for holding a steel ball 14 is formed at a predetermined position in the base. This holding hole 15 is in the form of an elongated hole that is elongated in the circumferential direction with the lever shaft 5 as the center. This means that the steel ball 14 that is loosely fitted into the holding hole 15 is inserted into any one of the click holes 7 of the click plate 7.
This is to allow for slight angular reciprocation within the range allowed by the elongated holes even if they are inserted into the holes a, 7b, . . . . Note that the steel ball 1 loosely fitted into the holding hole 15
4 is constantly pressed against the click plate 7 by a leaf spring 16.

The leaf spring 16 is integrally formed with a lower reel portion 16a having a lower outer peripheral portion 17 biased outward, and a spring portion 16b extending upward from the lower reel portion 16a. The lever main body 11 and the leaf spring 16 are assembled by fitting the respective support holes 12 and 18 onto the lever shaft 5. Note that the leaf spring 16 and the lever main body 11 are prevented from rotating relative to each other by fitting the locking hole 19 and the projection 20 into each other. This leaf spring 1
6, when assembled, the lower outer periphery 17 which is biased outward as described above and the base outer periphery of the lever main body 11 cooperate to form a reel for winding up the inner wire _W1 .

As mentioned before, although the bicycle gear shift lever according to this embodiment has a click mechanism, the lever body is made to reciprocate by a slight angle at each locking position, and the click mechanism With the help of , the rough rotational angle position of the lever can be determined, and further fine adjustments or overshift operations can be performed, so the lever body can be shifted at any position within the above-mentioned range of slight reciprocating movement. A means for applying frictional resistance is required to counter the return spring of the machine and stop it. The friction applying means according to the present invention is basically the same as the conventional one, and has a structure in which a friction applying member, which is made of, for example, resin and does not rotate relative to the lever shaft, is brought into pressure contact with the lever body. The gist of the present invention is a completely new structure for preventing the friction imparting member from rotating relative to the lever shaft. This structure is configured in the illustrated example as described below.

As shown in FIGS. 4 and 5, the lever shaft 5 has a helical shaft portion 21 formed at its distal end, and this portion has a constant width in the shaft diameter direction and a threaded portion 21 in the axial direction. A groove 22 having a constant depth is formed. On the other hand, a friction imparting member 23 is fitted into the lever shaft 5 at a portion located outside of the click plate 7, lever body 11 and leaf spring 16 when assembled.

As shown in FIGS. 6 to 8, the friction imparting member 23 has an approximately donut shape as a whole, and has a clamped portion 24 having a constant width extending across its diameter. The inner diameter of the donut is approximately equal to the outer diameter of the lever shaft 5, and the width of the clamped portion 24 is determined to be approximately equal to the width of the groove 22 formed in the lever shaft 5. In addition, in the illustrated example, as clearly shown in Figure 8,
The sandwiched portion 24 is made to protrude further outward by a certain length from the outer surface of the donut portion.

Next, the lever shaft 5 and the friction imparting member 23
The assembly structure and its effects will be explained based on FIGS. 9 to 12.

After fitting the click plate 7, the lever body 11, and the leaf spring into the lever shaft 5 in this order, and preferably further fitting the washer 26, the friction imparting member 2
3 is inserted into the lever shaft 5 so that its clamped portion 24 is engaged with the slot 22 of the lever shaft 5, as shown in FIGS. 9 and 10. Next, the nut 25 is screwed onto the helical shaft portion 21 of the lever shaft 5 to complete the assembly as shown in FIGS. 11 and 12.

As the nut 25 is screwed onto the screw shaft 21,
A slope effect acts on the pressure contact surface between the thread of the nut 25 and the thread of the helical shaft portion 21, and the helical shaft portion 21 deforms as the width of the groove 22 decreases, as shown by the arrow in FIG. However, the inner wall surface of this groove 22 tightens the clamped portion 24 of the friction imparting member 23, and thereby,
There is no possibility that a gap will occur between the clamped portion 24 and the groove 22, and therefore, there is no possibility that the friction imparting member 23 will rotate slightly due to the reciprocating rotation of the lever body 11. It disappears. At the same time, the friction imparting member 23 is pressed by the nut 25 via the washer 26 against the lever body 11, that is, the plate spring 16 in the illustrated example, so that this provides a predetermined sliding friction resistance against the rotation of the lever body 11. is granted.

In the illustrated example, the sandwiched portion 24 is formed to protrude further outward from the outer surface of the donut portion of the friction imparting member 23. In this case, the amount of deformation of the grooves that sandwich this portion is large, so the above-mentioned effect is further enhanced. Moreover, by forming it in this way, as shown in FIG. 12, when assembled, both longitudinal end surfaces 24b, 24b of the protrusion 24a are threaded by the nut 25, which prevents the nut 25 from loosening. Therefore, this also contributes to achieving the objective of the present invention.

The invention is not limited to the embodiments shown in the drawings. In the illustrated example, the clamped portion 24 of the friction imparting member 23 is made to protrude from the outer surface of the friction imparting member 23 by a certain height, but the effects of the present invention can be fully expected even if this protrusion is not formed.

Further, the groove 22 to be provided in the lever shaft 5 is formed to extend in the diametrical direction of the lever shaft, and the clamped portion of the friction imparting member 23 is also configured to have a shape corresponding to this. However, the present invention is not limited to this, and, for example, the grooves 23 and the sandwiched portions sandwiched therebetween may be formed in a cross shape. In short, when the nut 25 is screwed onto the helical shaft 21 of the lever shaft 5, the diameter of the helical shaft 21 is slightly reduced due to the presence of the split groove, and this causes the clamped part formed integrally with the friction imparting member 23 to be slightly reduced in diameter. All the shapes of the split grooves 22 and the clamped parts 24 that can be expected to have the effect that the friction applying member 23 does not rotate together with the reciprocating rotation of the lever main body are as follows: It is within the scope of the present invention.

Further, since the gist of the present invention lies in the structure for imparting a certain amount of frictional resistance to the lever body rotatably supported by the lever shaft, the shape of the bicycle gear shift lever as a whole does not matter. That is, in the illustrated example, the present invention is applied to a bicycle gear shift lever of a type with a built-in so-called click mechanism, but the present invention is not limited to this, and may be applied, for example, to the lever described in Japanese Utility Model Application Publication No. 128589/1989. , it can also be applied to small levers that do not have a click mechanism.

As explained above, the present invention is an excellent invention that can maintain a constant frictional resistance to be applied to the lever body with an extremely simple structure.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the whole of an example of a bicycle gear shift lever to which the present invention is applied, FIG. 4 and 5 show an example of a lever shaft, FIG. 4 is a side view, FIG. 5 is a plan view, and FIGS. 6 to 8 are perspective views showing main parts in an exploded state. An example of the friction imparting member is shown; FIG. 6 is a side view, FIG. 7 is a plan view, FIG. 8 is a cross-sectional view taken along the line -- in FIG. 7, and FIG. 9 shows the friction imparting member assembled to the lever shaft. The cross-sectional view shown in FIG.
11 is a sectional view showing an assembled state in which the nut is further screwed in from the state shown in FIG. 9, and FIG. 12 is a sectional view taken along the line XII--XII in FIG. 11. 5... Lever shaft, 11... Lever body, 21...
... Spiral shaft portion, 22 ... Division groove, 23 ... Friction imparting member, 24 ... Clamped portion, 25 ... Nut.

Claims (1)

[Scope of utility model registration request] A split groove is provided in the distal end spiral portion of the lever shaft that rotatably supports the lever body, and a friction imparting member having a pinched portion that can fit into the split groove is inserted into the split groove. A bicycle gear shift operating lever, characterized in that the friction imparting member is pressed toward the lever body by a nut screwed onto the threaded portion of the lever shaft while being fitted onto the lever shaft.