JP3152166U - Chain drop prevention tool - Google Patents

Abstract

A chain drop prevention device for preventing a chain from falling off in a multi-stage exterior speed change bicycle. A main body plate (2), a chain drop-off prevention piece (3) fixed to the main body plate (2), and an attachment piece (4) disposed relative to the main body plate (2) are provided. It is attached to the bicycle with the rear axle mounting frame sandwiched between them. In the attached state, the chain drop prevention piece 3 comes into contact with the chain that is going to drop outward from the outermost sprocket of the multi-stage sprocket attached to the rear wheel shaft to prevent the drop off. [Selection] Figure 1

Description

  The present invention relates to a bicycle chain drop-off prevention device.

  Recently, multi-stage exterior-shifted bicycles have become widespread, and multi-stage exterior-change bicycles are equipped with multi-stage sprockets on the rear wheel axle, and the sprockets used are switched by operating the derailleur with a shift shifter, so that the speed changes according to the driving situation. Is possible.

  In the case of the multistage exterior speed change bicycle, the chain may fall off the outermost sprocket (minimum number of teeth) of the multistage sprocket during traveling. The reasons for this drop-off include loose chain, use of wire for operating the derailleur, and improper adjustment of the derailleur. On the other hand, bicycles are often sold at large stores such as supermarkets. Therefore, when the chain is dropped as described above, there is a problem that the dealer cannot perform immediate repair.

  The present invention has been made in view of the above circumstances, and an object thereof is to prevent a chain from dropping off in a multi-stage exterior speed change bicycle.

  The device includes a main body plate, a chain drop-off preventing piece fixed to the main body plate, and an attachment piece disposed relative to the main body plate, and a bicycle is disposed between the main body plate and the attachment piece. It is mounted with the rear wheel shaft mounting frame sandwiched, and in this mounting state, the chain drop prevention piece contacts the chain that is about to drop outward from the outermost sprocket of the multi-stage sprocket attached to the rear wheel shaft, and removes the chain. Provided is a chain drop prevention device characterized by preventing the chain drop.

  By using the chain drop prevention tool with the above configuration, the chain drop prevention piece comes into contact with the rotating chain on the outermost sprocket during travel, even when force is applied in the drop direction (outward direction). Is prevented from falling off. The position of contact with the chain may be an appropriate position as long as it is a position that prevents the chain from falling off, but the chain is prevented from coming off effectively by being the position where the chain is introduced from the derailleur to the outermost sprocket. Dropping often occurs when the chain is not smoothly placed on the outermost sprocket from the derailleur, and dropping is prevented by placing the chain on the outermost sprocket by contacting the chain dropping prevention piece at that position. The

  The chain fall-off prevention piece has an arc-shaped structure, and the chain drop-off prevention piece has a circular cross section, so that the shock at the time of contact of the chain drop-off prevention tool with the chain is weakened.

  The chain drop-off prevention device can be easily, firmly and stably attached by sandwiching the rear wheel shaft attachment portion of the frame between the main body plate and the attachment piece. In particular, the mounting piece is configured to be integrally provided with a fitting portion that fits into a rear wheel shaft engaging cutout portion that is formed on the rear wheel shaft mounting frame and opens rearward, and / or the body plate is provided with the rear wheel shaft. By being arranged on the outer surface of the attachment frame so as to be engaged with the attachment portion of the derailleur, positioning at the time of attachment to the bicycle is facilitated and firmly fixed at a predetermined position. Further, since the main body plate and the mounting portion of the derailleur are placed flush with each other, the main body plate does not get in the way, and various parts can be attached to the upper portion without any trouble.

  By using the chain drop prevention device of this device, it becomes possible to reliably prevent the chain from dropping off from the multi-stage sprocket, and it is possible to run with a multi-stage exterior speed change bicycle with peace of mind. In particular, the chain drop prevention device of the present invention has an advantage that it can be attached to a bicycle easily, firmly and stably.

  FIG. 1 is a front view of a chain drop prevention device of the present invention, and FIG. 2 is a side view thereof. The chain drop prevention tool 1 is entirely made of metal and includes a main body plate 2, a chain drop prevention piece 3, and an attachment piece 4.

  The main body plate 2 includes a screw mounting hole 5 on the upper end side, and a fixing hole 6 for the chain drop-off preventing piece 3 on the lower end side. The chain drop-off prevention piece 3 is entirely formed of a bar piece having a circular arc shape and a circular cross section, and the base portion 13 is attached to the main body plate 2 by being fitted into the fixing hole 6 and fixed by caulking. . The mounting piece 4 is integrally provided with a fitting projection 7 on the surface facing the body plate 2, and a screw hole 8 is provided at a position of the fitting projection 7 facing the screw mounting hole 5 of the body plate 2. Yes. The chain drop prevention tool 1 is used in a state where the mounting screw 9 inserted from the screw mounting hole 5 of the main body plate 2 is screwed into the screw hole 8 of the mounting piece 4 and integrated.

  3 and 4 show how the chain drop prevention device 1 is attached to a bicycle, and FIGS. 5 and 6 are explanatory views of attachment. Reference numeral 10 denotes a mounting portion for the rear wheel shaft 11 of the bicycle frame F, and the rear wheel shaft 11, the derailleur 12, the chain drop prevention device 1, the derailleur guard 14, and the stay 16 are mounted and fixed on the mounting portion 10, respectively. The mounting portion 10 is provided with a notch 40 that opens rearward. The rear wheel shaft 11 that is engaged with the notch 40 has a derailleur 12 mounting portion 12 a, a derailleur guard 14 mounting portion 14 a, and a stay 16. Each of the attachment portions 16a is sequentially attached, and then a fixing nut 18 is screwed onto the end of the wheel shaft 11 and tightened to fix all of them.

  The chain drop prevention tool 1 is such that the main body plate 2 is attached to the outer surface of the attachment portion 10 of the bicycle frame F, the attachment piece 4 is along the inner surface, and the engagement convex portion 41 of the main body plate 2 is engaged with the attachment portion 12a of the derailleur. It is attached by engaging the fitting recess 43 and tightening the attachment screw 9 in a state where the fitting convex portion 7 of the attachment piece 4 is fitted to the end portion of the notch portion 40 of the attachment portion 10.

  The chain drop prevention tool 1 can be easily, firmly, and stably attached by sandwiching the attachment portion 10 of the frame F between the main body plate 2 and the attachment piece 4 as described above. In particular, the engaging convex portion 41 of the main body plate 2 engages with the engaging concave portion 43 of the derailleur mounting portion 12 a, and the fitting convex portion 41 of the mounting piece 4 is at the end of the notch portion 40 of the mounting portion 10. By being attached in the fitted state, positioning at the time of attachment is facilitated and firmly fixed to a predetermined position. Thus, even when the bicycle is subjected to vibrations or an impact caused by the chain coming into contact with the chain drop-off preventing piece 3, it is possible to avoid displacement. Further, since the body plate 2 and the mounting portion 12a of the derailleur 12 are flush with each other, the mounting portion 14a of the derailleur guard 14 and the mounting portion 16a of the stay 16 can be mounted without hindrance without the body plate 2 being in the way. can do.

  In the attached state, the chain drop prevention piece 3 of the chain drop prevention tool 1 is positioned so as to wrap around the lateral lower portion of the outer side surface of the outermost sprocket 20a of the multistage sprocket 20 attached to the rear wheel shaft 11. By attaching the hub axle fixing nut 19 to the rear wheel shaft 11, a space S is formed between the attachment portion 10 of the bicycle frame F and the outermost sprocket 20a, and the chain C that has fallen from the outermost sprocket 20a in the space S is conventionally provided. I got stuck.

  The chain drop prevention tool 1 is used, and the chain drop prevention piece 3 wraps around and is positioned at the lower side of the outer side surface of the outermost sprocket 20a, so that the chain C on the outermost sprocket 20a from the derailleur 12 side is assumed during traveling. Even when a pulling force is applied to the dropout direction (outward direction), the side face of the chain drop prevention piece 3 supports the side face of the chain C at the introduction position X from the derailleur 12 of the chain C to the outermost sprocket 20a. As a result, the chain C is forcibly fed onto the outermost sprocket 20a and the fitting of the chain C into the space S is prevented, thereby preventing the chain C from falling off. Although the derailleur 12 is slightly displaced in the front-rear direction (on the bicycle) by the operation of the shift shifter, the chain drop-off prevention piece 3 is present with a predetermined length in that direction, so that the derailleur 12 is at an appropriate position corresponding to the displacement. It comes into contact with the chain C and exhibits a drop-off prevention function. The drop-off prevention piece 3 is curved and has a strong structure, and its cross-section is circular and the contact surface is curved, so that the shock associated with the contact with the side surface of the chain C is weakened and the chain is damaged. Is to reduce.

  Front view of an embodiment of the chain drop prevention device of this device   Side view of an embodiment of the chain drop prevention device of the present invention   Installation use state diagram of the embodiment of the chain drop prevention device of this device   Installation use state diagram of the embodiment of the chain drop prevention device of this device   Installation explanatory diagram of the embodiment of the chain drop prevention device of this device   Installation explanatory diagram of the embodiment of the chain drop prevention device of this device

DESCRIPTION OF SYMBOLS 1 Chain drop prevention tool 2 Main body plate 3 Chain drop prevention piece 4 Mounting piece 11 Bicycle rear wheel shaft 12 Derailleur 20 Multistage sprocket 20a Outermost sprocket C Chain F Rear wheel shaft mounting frame

Claims (6)

A main body plate, a chain drop-off preventing piece fixed to the main body plate, and an attachment piece disposed relative to the main body plate,
The bicycle is mounted with a bicycle rear wheel shaft mounting frame sandwiched between the main body plate and the mounting piece, and in this mounting state, the chain drop prevention piece is removed from the outermost sprocket of the multistage sprocket mounted on the rear wheel shaft. A chain drop prevention tool characterized in that it comes into contact with a chain that is about to fall off and prevents the chain from falling off.   The chain drop prevention tool according to claim 1, wherein the contact is made at an introduction position from the derailleur of the chain to the outermost sprocket.   The chain drop prevention tool according to claim 1, wherein the chain drop prevention piece has an arc shape.   The chain drop prevention tool according to claim 1, wherein a cross-section of the chain drop prevention piece is circular.   The chain drop prevention device according to claim 1, 2, 3, or 4, wherein the mounting piece integrally includes a fitting portion that fits into a rear wheel shaft engagement cutout portion that is formed in the rear wheel shaft mounting frame and opens rearward. .   6. The chain drop prevention device according to claim 5, wherein the main body plate is disposed on the outer surface of the rear wheel shaft mounting frame so as to be flush with and engage with a derailleur mounting portion.

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