JPH0315439Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to a front derailleur for a bicycle, and more particularly, to one configured so that the angle of a chain guide with respect to a sprocket and the vertical position with respect to a bicycle frame can be adjusted separately.

[Conventional technology]

The structure of a conventional bicycle front derailleur is basically as follows. That is, a base member is fixed to a bicycle frame, for example, near a hanger hook at the bottom of a seat pipe, with a clamp band, and a movable member is attached to this base member via a control mechanism such as a parallelogram pantograph link mechanism. be done. In the parallelogram pantograph link mechanism, the upper ends of the outer link member and the inner link member are swingably connected to the base member by pin connection, and the movable member is connected to the lower ends of these inner and outer link members by pin connection. It is constructed by being connected. The pantograph link mechanism is constructed by inserting a torsion spring into a pin that connects the inner link member and the movable member, and hooking both ends of the spring to a fixed member and a movable member on the base member side, respectively. It has a tendency to deform in this direction, and is deformed by swinging the inner and outer link members against the torsion spring using an operating cable. A pair of inner and outer chain guides each having an arcuate lower edge corresponding to the outer periphery of the sprocket are attached to the movable member. This chain guide is arranged to sandwich the chain in front of the front gear sprocket from the inside and outside, and by moving it in parallel in the inside and outside directions, it forcibly presses the chain in the outside and outside directions, allowing it to be replaced. It is designed to hang on the sprocket you are trying to use. On the other hand, the front sprockets of bicycles have different diameters depending on the model, so if the front derailleur described above is applied to each bicycle equipped with sprockets of different diameters, the chain guide will fit around the outer circumferential surface of the sprocket. If the sprocket does not line up properly, or if there are differences in the vertical position relative to the sprocket or the angle relative to the bottom bracket, the chain change operation between the sprockets via the chain guide may not be performed properly, which may impede gear shifting operation. Become. Therefore, in the past, there have been some devices in which the position of the chain guide relative to the sprocket can be adjusted by, for example, making the position of the base member that supports the movable member adjustable. This type of front derailleur is disclosed, for example, in Japanese Patent Publication No. 54-41775. In this conventional front derailleur, a mounting plate fixed to the frame has a mounting surface with a cylindrical inner surface extending vertically, and a long elongated hole is bored in the vertical direction, while a chain guide is connected via a pantograph link mechanism. A cylindrical outer joint surface corresponding to the mounting surface is provided on the base member to be supported, and with the joint surface on the base member side joined to the mounting surface on the mounting plate side, these mounting surfaces and joint surfaces are connected to each other. It is fixed with a bolt passed through the elongated hole mentioned above. When the bolts are loosened, the base member can move vertically relative to the mounting plate within the range allowed by the elongated hole, and can also move relative to the mounting plate around the center axis of the inner or outer surface of the cylinder. Can be rotated laterally. Therefore, by loosening the bolt and setting the rotational position and vertical position of the base member as desired, and then tightening the bolt, the angle of the chain guide with respect to the sprocket and the vertical position can be adjusted at the same time.

[Problem that the invention attempts to solve]

However, in the conventional derailleur disclosed in the above-mentioned publication, a single bolt is used to fix the chain guide after it has been adjusted in the rotating direction and to fix it after it has been adjusted in the vertical direction. However, there is a problem in that adjustment is difficult. That is, it is extremely difficult to simultaneously select appropriate angles and vertical positions of the chain guide with respect to the sprocket, and to hold these positions by hand until the bolts are tightened. Furthermore, if you only want to readjust the vertical position, for example, loosening the bolts will cause the angle to the sprocket, which does not need to be adjusted, to be incorrect, and if you do so, you will have to perform the difficult and delicate adjustment work described above from the beginning. . This idea was devised under the above circumstances, and allows the angle and vertical position of the chain guide relative to the sprocket to be adjusted separately, dramatically improving the ease of adjusting the chain guide. The object of the present invention is to provide a front derailleur for a bicycle that has the following characteristics.

[Means to solve the problem]

In order to solve the above problems, this invention adopts the following technical means. In other words, the bicycle front derailleur according to this invention has a pedestal that is movable and adjustable only in the vertical direction with respect to the bicycle frame, and a pedestal that rotates only at an angle about the vertical axis with respect to the pedestal. a base member that is adjustable;
It includes a movable member connected to the base member via a control mechanism so as to be able to move in parallel in the inner and outer directions, and a pair of inner and outer chain guides supported by the movable member.

[Action and effect]

The position adjustment of the chain guide relative to the sprocket in the front derailleur according to this invention is performed as follows. First, when adjusting the vertical position of the chain guide, the pedestal is moved in the vertical direction of the bicycle frame and fixed at a predetermined position. Further, when adjusting the swing angle of the chain guide with respect to the sprocket, the base member is rotated about the vertical axis of the pedestal and fixed at a predetermined angular position. At this time, the pedestal is provided so as to be movable and adjustable only in the vertical direction with respect to the bicycle frame, and on the other hand, the base member is provided so that only the rotation angle around its vertical axis can be adjusted with respect to the pedestal. This makes it possible to carry out each adjustment operation separately and independently. Therefore, there is a problem with conventional examples in which the base member is fixed to the mounting member with a single bolt, that is, once the bolt is loosened, the height position of the chain guide and the rotational position relative to the sprocket will change. This solves the problem of both of the chain guide being out of alignment, making it possible to accurately and reliably adjust the chain guide's vertical position and its angle with respect to the sprocket. Readjustment is also possible.

[Explanation of Examples]

Hereinafter, embodiments of this invention will be described in detail with reference to FIGS. 1 to 4. A mounting member 2 having an oval-shaped cross section is fixed by welding or the like near the hanger hook of the vertical pipe. A pedestal 3 is attached to the mounting member 2 so that its position can be adjusted only in the vertical direction, and a base member 4 is further attached to the pedestal 3 so that its rotational position can be adjusted about an axis in the vertical direction. A movable member 6 is supported on the base member 4 and is movable in parallel in the width direction of the bicycle via a control mechanism including a parallelogram pantograph link mechanism 5 and the like. This movable member 6 has a pair of guide plates 20 and 21 positioned to sandwich the chain that is about to hang on the front sprocket from the inside and outside.
A chain guide 22 consisting of the following is attached. The mounting member 2 has a rear surface 2 on its base end side 2a.
b, a first holding surface 2c having a substantially cylindrical inner surface capable of holding the outer surface of the vertical pipe 1;
e has a second holding surface 2f having a cylindrical inner surface shape,
The first holding surface 2c is fixed to the vertical pipe 1 by abutting it against the right outer surface of the vertical pipe 1 and welding it. The second holding surface 2f extends linearly in the vertical direction and has an elongated through hole 2g that is long in the vertical direction. The pedestal 3 is formed into a substantially inverted E-shape in side view, as if the rear surface of a rod member having a substantially elliptical cross section is cut into rectangular grooves at two vertically apart locations. Second holding surface 2 of mounting member 2
A support section 3c having a front sliding surface 3b having a cylindrical outer surface shape that fits and slides into contact with the support section f, and an upper support section 3d that is connected in the horizontal direction from the upper and lower ends of the support section 3c, respectively. , a lower support part 3e, and a central support part 3f that is connected in the horizontal direction from the center of the support column 3c. Support holes 3g, 3h, and 3i having the same vertical axis are formed in the upper support portion 3d, lower support portion 3e, and center support portion 3f, respectively. Further, a screw hole 3j penetrating from the support portion 3c of the pedestal 3 to the holding hole 3h of the central support portion 3f is opened in a direction perpendicular to the axis from the sliding surface 3b side. A bolt 8 passed through the elongated through hole 2g of the mounting member 2 is screwed into the screw hole 3j, whereby the pedestal 3 is fixed to the mounting member 2. In this way, the pedestal 3 can be configured such that the through hole 2g of the mounting member 2 is aligned with the bolt 8 by loosening the bolt 8 and sliding its sliding surface 3b against the second holding surface 2f of the mounting member 2. It is movable up and down a permissible distance. However, as shown in Figure 3,
A shoulder portion 3m, 3n formed on both the left and right edges of the sliding surface 3b of the pedestal 3 is a stepped portion 2h formed on the mounting member 2,
2h, the base 3 is prevented from rotating relative to the mounting member 2. Note that the other end 2d of the mounting member 2 is located between the seat surface 8a of the bolt 8 and the mounting member 2.
A washer 9 is interposed which has a holding surface 9a capable of holding on the back surface 2b side. Further, the base member 4 is capable of exhibiting a hinge function in cooperation with the pedestal 3,
Upper and lower notched recesses 3 formed by the upper support portion 3d, center support portion 3f, and lower support portion 3e of the pedestal 3
It has fitting portions 4a and 4b that fit into the holes 4a and 3k, respectively. The upper and lower notched recesses 3k, 3k and the fitting parts 4a, 4b are set to have a certain amount of play in their fitted state, and the upper fitting part 4a has each support hole 3g, 3i of the pedestal, A bolt through hole 4c having the same diameter as 3h is formed in the lower fitting portion 4b, and a screw hole 4d concentric with the bolt through hole 4c is formed in the lower fitting portion 4b. Then, with the fitting parts 4a, 4b of the base member 4 fitted into the notch recesses 3k, 3k of the base, the bolts 7 are inserted through the support hole 3g, bolt through hole 4c, and support hole 3h. , screw into the screw hole 4d. As a result, the base member 4
is connected to the pedestal 3 so as to be rotatable in the left-right direction about a bolt 7 as a pivot. When the bolt is tightened, the pedestal side supports 3g, 3h and the base member side fitting part 4a are pinched between the head 7a of the bolt 7 and the lower fitting part 4b, and the base member 4 is held in a predetermined position. Fixed in rotation angle position. The pantograph link mechanism 5 connects the inner link member 10 and the outer link member 11 to the base member 4 with pins 1 at their upper ends.
The movable member 6 is connected to the lower ends of these inner and outer link members 10 and 11 via pins 14 and 15. In addition, the base member 4
pins 12 and 13 for joining the inner and outer link members 10 and 11, and the inner and outer link members 1
Pins 14 and 15 for joining 0 and 11 to the movable member 6 are located so as to form each vertex of a parallelogram. That is, when the inner and outer link members 10 and 11 are swung relative to the base member 4, the movable member 6 moves in parallel in the inner and outer directions while keeping its directionality constant. This parallelogram pantograph link mechanism 5 is always biased so that the movable member 6 moves inward by a torsion spring 16 inserted into a pin 14 that connects the inner link member 10 and the movable member 6. An operating arm 17 extending above the outer link member 11
The deformation operation is performed by pulling the operation cable W fixed to the. moreover,
The range of deformation of the parallelogram pantograph link mechanism 5 is such that the ends of the inner stopper bolts 18 and outer stopper bolts 19 screwed into appropriate portions of the base member 4 are connected to the inner link member 10, respectively.
It is regulated by coming into contact with a stopper surface 10a formed at the upper end of. That is, by adjusting the screwing of the inner stopper bolt 18 and the outer stopper bolt 19, the range of movement of the movable member 6 is changed. A chain guide 22 is attached to the movable member 6, and includes an inner guide plate 20 and an outer guide plate 21, which are located substantially parallel to the sprocket S and face each other at a predetermined distance. The outer guide plate 21 and the inner guide plate 20 are each connected to the movable member 6 at their upper portions. Further, the rear end portions of these inner and outer guide plates 20, 21 are connected to pins 23.
connected by. The position adjustment of the chain guide 22 in the front derailleur having the above configuration is performed as follows. When adjusting the vertical position of the chain guide 22, first loosen the bolt 8, and then move the sliding surface 3b of the pedestal a desired distance vertically relative to the second holding surface 2f of the mounting member 2. After that, the pedestal 3 is fixed by tightening the bolt 8. When adjusting the angle of the chain guide 22 with respect to the sprocket S, first loosen the bolt 7, rotate the base member 4 by the desired angle around the bolt 7, and then tighten the bolt 7. The base member 4 is fixed to the pedestal 3. In this way, the vertical position adjustment of the chain guide 22 with respect to the bicycle frame 1 and the angle adjustment with respect to the sprocket S can be performed separately, making the work easier than in the conventional example. Of course, the scope of this invention is not limited to the above embodiments. Although the vertical movement direction of the pedestal with respect to the mounting member is parallel to the vertical pipe in the embodiment, it is not particularly necessary to be parallel to the vertical pipe. In short, the direction of the chain guide may be set so that it approaches or moves away from the outer periphery of the sprocket in the radial direction. Further, in the embodiment, the rotation axis of the base member relative to the pedestal is determined by a bolt arranged parallel to the vertical pipe, but the direction of the bolt does not need to be strictly parallel to the vertical pipe.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the present invention, Fig. 2 is an enlarged vertical sectional view thereof, Fig. 3 is an enlarged view in the direction of the arrow in Fig. 1, and Fig. 4 is an enlarged view in the direction of the arrow in Fig. 1. It is a diagram. 1... Bicycle frame (standing pipe), 3... Pedestal,
4... Base member, 6... Movable member, 22... Chain guide.

Claims (1)

[Scope of utility model registration request] a pedestal provided to be adjustable in movement only in the vertical direction with respect to the bicycle frame; a base member provided in relation to the pedestal so as to be adjustable only in its rotation angle about its vertical axis; and the base. A front derailleur for a bicycle, comprising: a movable member connected to the movable member via a control mechanism so as to be movable in parallel in the inward and outward directions; and a pair of inner and outer chain guides supported by the movable member.