Rear fork chain guide

Abstract

A chain guide according to the present invention includes: a guide seat, a support portion, and a connecting portion. The guide seat includes: a bottom; an inner sidewall standing on one side of the bottom; and an outer sidewall protruding from the other side of the bottom, the outer sidewall facing the inner sidewall. The guide seat has two communicating openings. The support portion is connected to the bottom, and the support portion and the outer sidewall are on the same side. The connecting portion is connected to the guide seat via the support portion, forming a recess on the back of the chain guide. A folding bicycle is equipped with a frame, a chain, and a chain hook. The frame has a rear fork on which the chain guide is mounted. The chain is connected end-to-end and can circulate within the frame. The chain hook is mounted on the frame without affecting the circulating movement of the chain. When folded, the chain hook catches the chain, the chain is inserted into the guide seat and crosses the rear fork, and the chain guide separates the chain from the rear fork to prevent collision.

Description

Rear fork chain guide This invention relates to a bicycle during folding, and more particularly to a chain guide that guides a chain across a frame to reduce the chance of collision between the two. Typically, this bicycle frame has a front fork and a rear fork. The front fork mounts a front wheel, and the rear fork mounts a rear wheel. The front and rear wheels roll in contact with a road surface, supporting the bicycle's movement. The bicycle has a chain connecting the beginning and end, which is looped around a chainring and a freewheel. The freewheel is mounted on one side of the rear wheel. The chainring is mounted on the frame, and a force from the chainring is transmitted to the freewheel via the chain, driving the rear wheel forward on the road. The frame has a fixed length, and the front and rear wheels are spaced a considerable distance apart, which is disadvantageous for transporting the bicycle. To reduce the length of the bicycle, the industry improved the frame structure to create a folding bike series. However, the distance from the chainring to the freewheel is shortened due to the folding of the frame, causing a slack in the chain tension and creating a new problem of the chain falling off. To address the problem of chain slippage, a chain hook has been developed to catch the chain, maintaining its tension and preventing it from detaching from the sprocket and freewheel. For details on the specific structure of this chain hook, interested parties can refer to Chinese Patent No. 217227808U and Taiwanese Patent Nos. I508895B and M396254U1. Inevitably, the chain hook will snag on the chain, which may then collide with the frame, causing friction and wear, and creating new problems. In view of this, the inventor of this case provides a chain guide, the main purpose of which is to: adopt a accommodating mechanical structure to receive and guide the chain to cross the frame in accordance with the hooking action of the chain guide, and use the chain guide to separate the chain from the frame, thereby effectively solving the drawback of friction-induced wear. To achieve the aforementioned objectives, the chain guide of the present invention includes: a guide seat, a support portion, and a connecting portion. The guide seat includes: a bottom; an inner sidewall standing on one side of the bottom; and an outer sidewall protruding from the other side of the bottom, the outer sidewall facing the inner sidewall. The guide seat has two communicating openings. The support portion is connected to the bottom, and the support portion and the outer sidewall are on the same side. The connecting portion is connected to the guide seat via the support portion, forming a recess on the back side of the chain guide. A folding bicycle is equipped with a frame, a chain, and a chain guide. The frame has a rear fork with the chain guide attached. The chain is connected end-to-end and can circulate within the frame. The chain guide is mounted on the frame without affecting the chain's circulation. When folded, the chain guide hooks onto the chain, which is then inserted into the guide and crosses over the rear fork. The chain guide separates the chain from the rear fork to prevent collision. To make the objectives, features and advantages of the present invention readily apparent, one or more preferred embodiments are described in detail below with reference to the accompanying drawings. Next, embodiments of this case will be described with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or similar structures or units. It is to be understood that the described embodiments are only some examples of this case, and not all embodiments. Other embodiments can be deduced based on the described examples, or constructions can be modified or varied as needed, all of which fall within the scope of protection of this case. In the following description, directional terms such as "up," "down," "left," "right," "front," "back," "inside," "outside," and "side" are used only for reference to the directions in the accompanying drawings. The use of directional terms is for the purpose of better and clearer description and understanding of this application, and does not imply that the described device or element must have a specific orientation, structure, or operation, and therefore should not be construed as a limitation on the technical content of this application. Unless specifically and explicitly stated otherwise, in the following description, "installed," "connected," "attached," or "on" should be interpreted broadly, including, for example, fixed connection, detachable connection, integral connection, mechanical connection, direct connection, indirect connection, or connection between two components. Those skilled in the art will understand the meaning of these terms in various embodiments, and even in the specific context, based on ordinary knowledge or experience. Unless otherwise stated, in the following description, "multiple" means two or more. Figure 1 shows a partial structure of a bicycle (unnumbered). The bicycle has a frame 10, which is foldable, hence it is also called a folding bicycle. The frame 10 has a bottom bracket (unnumbered), with a chainring 14 attached to its end. Multiple teeth (unnumbered) form the circumference of the chainring 14. The frame 10 also has a rear fork 11, the end of which is connected to a rear wheel (not shown). Multiple co-rotating freewheels 12 are mounted on one side of the rear wheel. Each freewheel 12 has a different diameter and therefore a different number of teeth. A chain 15, with its ends connected, is fitted over the freewheels 12 and the chainring 14, engaging the corresponding teeth. A rear derailleur 13 is mounted on the rear fork 11. The rear derailleur 13 changes the tension of the chain 15, allowing the chain 15 to adapt to the different diameter freewheels 12, thus changing the speed of the rear wheel. The bicycle is equipped with a chain hook 16, which is mounted on the rear derailleur 13. Normally, the chain hook 16 does not interfere with the chain 15's circulation around the freewheel 12 and the sprocket 14. When the frame 10 is folded, the chain hook 16 engages the chain 15 (see Figure 6) to prevent slack in tension, and the chain 15 still maintains its transmission relationship with the sprocket 14 and freewheel 12. Additionally, the bicycle has a chain guide 20, which is mounted on the rear fork 11. The placement of this chain guide 20 is significant; it is adjacent to the freewheel 12 and falls precisely within the loop of the chain 15. Normally, the chain guide 20 does not interfere with the circular motion of the chain 15. When the frame 10 is folded down, the chain hook 16 engages the chain 15, causing the chain 15 to fall into the chain guide 20 and intersect with the rear fork 11 (see Figure 6). Therefore, the chain guide 20 separates the chain 15 from the rear fork 11, preventing unnecessary frictional wear caused by their collision. As shown in Figure 2, in a preferred embodiment of the present invention, the chain guide 20 is divided from top to bottom into: a guide seat 21, a baffle 27, a support portion 28, and a connecting portion 29. The support portion 28 connects the guide seat 21 and the connecting portion 29 together. The baffle 27 protrudes from one side of the chain guide 20. In this embodiment, the guide seat 21 is located on the upper part of the chain guide 20. The guide seat 21 includes a bottom 22, an inner sidewall 23, and an outer sidewall 24. The inner sidewall 23 stands on one side of the bottom 22. The outer sidewall 24 protrudes from the other side of the bottom 22 and faces the inner sidewall 23. The guide seat 21 forms an open slot with two communicating openings 25 and 26. The support portion 28 is connected to the bottom 22, and it is on the same side of the outer side wall 24 as the chain guide 20. The lower end of the support portion 28 is connected to a portion of the top surface of the connecting portion 29, forming a recess 31 on the back side of the chain guide 20 (see Figure 3). In this embodiment, the support portion 28 is a hollow frame. In other embodiments, the support portion 28 is a solid sheet. The baffle 27 is integral with the bottom 22. One end of the baffle 27 is connected to the root of the inner sidewall 23, and the other end of the baffle 27 is connected to the support 28, so that the baffle 27 is tilted and blocked to the lower right of the opening 25 of the guide seat 21. The connecting portion 29 is located at the lower part of the chain guide 20. Two fixing holes 30 form the connecting portion 29. One end of each fixing hole 30 extends to the outside of the connecting portion 29 and has a larger diameter. The other end of each fixing hole 30 extends to the inside of the connecting portion 29 (see Figure 3) and has a smaller diameter. Each fixing hole 30 is a fisheye hole. In Figure 4, when a user faces the end of the connector 29, it can be seen that the side of the support 28 closest to the user is tilted, while the side of the support 28 furthest from the user is twisted. Therefore, the support 28 is twisted, and the opening 26 supporting the guide seat 21 is farther away from the connector 29 than the other opening. As shown in Figure 5, a virtual straight line 32 is planned along one length direction of the guide seat 21, passing through the two openings 25 and 26. Since the opening 25 of the guide seat 21 is closer to the connecting portion 29 than the other opening 26, the straight line 32 is obliquely intersecting the length direction of the connecting portion 29. In addition, the baffle 27 extends outward from the inner wall 23 along the length direction of the chain guide 20, and the baffle 27 gradually slopes from the opening 25 towards the tip. As shown in Figures 2-4, in this embodiment, the chain guide 20 uses a screw-locking method to secure the connecting portion 29 to the outside of the rear fork 11. The screw-locking method, as used herein, generally refers to a fastener 18 passing through the fixing hole 30 and locking into a connecting portion 17 of the rear fork 11. Specifically, the fastener 18 is a headed bolt that tightens the connecting portion 17 until the head is fully inserted into the fixing hole 30, thus maintaining a flat surface on the outside of the connecting portion 29. Simultaneously, the recess 31 of the chain guide 20 receives the rear fork 11, and the support portion 28 supports the guide seat 21, partially shielding the rear fork 11 (see Figure 5). In other embodiments, the recess 31 of the chain guide 20 is attached to the outer side of the rear fork 11 using an adhesion method. For example, a double-sided adhesive is bonded between the connecting portion 29 and the joining portion 17, allowing the chain guide 20 to adhere to the outer side of the rear fork 11. Alternatively, the back of the support portion 28 can be adhered to the outer side of the rear fork 11 using the double-sided adhesive, which is also a good option. Even the bottom surface of the guide seat 21 can be adhered to the outer side of the rear fork 11 using the double-sided adhesive, achieving the function of attaching the chain guide 20 to the rear fork 11. As shown in Figure 5, the straight line 32 intersects the length direction of the rear fork 11 at an angle, causing the guide seat 21 to obliquely cover part of the rear fork 11. In addition, the baffle 27 contacts the outer surface of the rear fork 11, causing the chain guide 20 to remain stationary on the outside of the rear fork 11. As shown in Figures 5 and 6, the chain hook 16 engages the chain 15. The chain 15, still engaged with the sprocket 14 and the freewheel 12, maintains a transmission relationship, preventing chain slippage. Following the direction of straight line 32, the chain 15 enters the guide seat 21 through opening 26 and then passes through another opening 25 of the guide seat 21. The bottom 22 supports the chain 15, preventing it from contacting the rear fork 11. The outer side wall 24 prevents the chain 15 from jumping out of the guide seat 21. The inner side wall 23 prevents the chain 15 from displacing towards the rear fork 11. The chain 15 is placed into the guide seat 21, turning at opening 25 and extending to the chain hook 16. Simultaneously, the baffle 27 is between the chain 15 and the rear fork 11. Thus, the guide seat 21 receives the chain 15, and the chain guide 20 guides the chain 15 across the rear fork 11, preventing collisions and frictional wear. Without departing from the broad concept of this case, those skilled in the art can understand and modify the above-described embodiments. Therefore, this case is not limited to the specific embodiments disclosed in the specification, and all modifications made in accordance with the spirit and technical scope of this case should be covered and protected by the textual content defined in the patent application. 10: Frame 11: Rear Fork 12: Freewheel 13: Rear Derailleur 14: Chainring 15: Chain 16: Chain Hook 17: Joint 18: Fastener 20: Chain Guide 21: Guide Seat 22: Bottom 23: Inner Side Wall 24: Outer Side Wall 25, 26: Opening 27: Baffle 28: Support 29: Connecting Part 30: Fixing Hole 31: Recess 32: Straight Line Figure 1 illustrates a preferred embodiment of the chain guide of the present invention used in a bicycle. Figure 2 shows the specific structure of the chain guide. Figure 3 depicts the structure of the back of the chain guide. Figure 4 shows the functional shape of the chain guide from the side. Figure 5 shows an overhead view of the relationship between the chain guide and the rear fork. Figure 6 shows the chain guide guiding the chain to be hooked by the chain hook. 11: Rear fork 13: Rear transmission 15: Chain 16: Chain hook 18: Fasteners 20: Chain Guide 21: Guide seat 27: Baffle 28: Support section 29: Connecting Part

Claims

1. A rear fork chain guide, attached to a frame (10) and a chain guide (20) mounted on the rear fork (11); the chain guide (20) includes: A guide seat (21) having a bottom (22) with an inner wall (23) on one side of the bottom (22) and an outer wall (24) protruding from the opposite side of the bottom (22) and facing the inner wall (23), so that the guide seat (21) has two communicating openings (25, 26); a support (28) connected to the bottom (22) and located on one side of the chain guide (20) along with the outer wall (24); and a connecting part (29) connected to the support (28) for mounting the chain guide (20) to the outside of the rear fork (11). The rear fork chain guide as described in claim 1, wherein... The chain guide (20) also includes a baffle (27) integrally formed with the bottom (22) and extending from the inner sidewall (23) to the support (28), obliquely covering one of the openings (25). The rear fork chain guide as described in claim 1, wherein... The support (28) is a twisting member that causes one of the openings (26) to deviate from the position of the connecting part (29) relative to the other openings (25), thereby forming an inclined guide channel. The rear fork chain guide as described in claim 1, wherein... The chain guide (20) has a recess (31) which is surrounded by the guide seat (21), the support (28) and the connecting part (29) and is located on the back of the chain guide (20) to accommodate the rear fork (11). The rear fork chain guide as described in claim 4, wherein... The connecting part (29) has at least one fixing hole (30), through which a fastener (18) passes and locks to a joint (17) of the rear fork (11) to fix the chain guide (20) to the rear fork (11). The rear fork chain guide as described in claim 4, wherein... At least a portion of the recess (31) can be fixed to the outside of the rear fork (11) via an adhesive structure. A chain guide for a rear fork is provided, wherein a chain guide (20) as described in any one of claims 1 to 6 is mounted on the rear fork (11) of a folding frame (10). When the frame (10) is equipped with a chain (15) and a chain hook (16), during the folding process of the frame (10), the chain hook (16) hooks the chain (15), so that the chain (15) is introduced through one of the two openings (26), passes through the guide seat (21), and is exited through the remaining opening (25), intersecting on the outside of the rear fork (11) and supported and positioned by the guide seat (21) to avoid frictional wear caused by collision between the chain (15) and the rear fork (11).

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