JPH0236795Y2 - - Google Patents

Description

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

With regard to bicycle chains, this invention improves the ease of changing to one of the multi-speed gears, that is, the gear shifting performance, and also improves the ease of shifting to a selected gear among multiple gears. This relates to an improved gear that is difficult to disengage from the currently engaged gear even if the gear is reversed.

[Conventional technology]

A bicycle transmission forcibly displaces the part of the moving chain on the side that enters the multi-stage gear in the lateral direction, disengaging the chain from the gear it is currently engaged in, and pulling it against the tip of the gear to be replaced. It is configured to change gears by engaging the gear. In the rear transmission, the means for moving a part of the chain laterally is a guide pulley that moves the chain toward the freewheel.
It is constructed with an interchangeable frame that supports a tension pulley to apply tension to the chain, and this interchangeable frame is moved laterally using a pantograph ring mechanism, etc., to cause the above-mentioned displacement of the chain. . When changing gears with such a transmission, it is generally easier to change the chain from a large diameter gear to a small gear, or to change the chain from a small gear to a large gear. Bad sex. In the former case, as long as the chain can be disengaged from the large-diameter gear, the chain will automatically fall into the small-diameter gear and engage with it, but in the latter case, the chain should first be disengaged from the small-diameter gear and then ,
Furthermore, in addition to the difference in outer diameter between the large and small gears and the need to lift the chain,
In order to finally replace the chain with a larger diameter gear,
This is because the link plate on the large diameter gear side has to go over the teeth of the gear. An example of a technology that attempts to solve the problem of poor shifting performance when changing a chain from a small-diameter gear to a large-diameter gear from the viewpoint of the chain shape is shown in Japanese Utility Model Publication No. 55-53806, for example. There is something. In the chain shown in this publication, the intermediate lower edge of the link plate is cut out in a large concave shape. In this way, when using a freewheel, when moving the transmission changing frame to the left to change the chain attached to the small-diameter gear to the large-diameter chain, the above-mentioned cutout of the right link plate can be used. passes over the teeth of the small-diameter gear, making it easier for the chain to separate from the small-diameter gear, and the cut portion of the left link plate becomes easier to get over the teeth of the large-diameter gear. Improves the ease of changing chains to gears.

[Problem that the invention attempts to solve]

However, as mentioned above, the fact that the chain is easier to change between gears means that the chain is more likely to come off the gear it is currently engaged in even if the direction of its running line is slightly inclined relative to each gear. It also means becoming. This type of chain dislodgement occurs in the following cases. In other words, the chain C running lines CLa, CLb run between the rear gear, that is, the freewheel, and the front gear.
However, as shown by the imaginary line in FIG. 8, this is a case where the chain C is inclined to the gear and the pedal is rotated in the opposite direction to cause the chain C to run in the opposite direction. Modern bicycles have a rear gear with five or more different diameter gears installed in parallel for the rear transmission, and a front gear with about three different diameter gears installed in parallel for the front transmission. , for example, if chain C meshes with the innermost gear of the rear gear and the outermost gear of the front gear (CLb), and if chain C meshes with the outermost gear of the rear gear. , and is meshing with the innermost front gear (CLa), the chain line will be considerably inclined with respect to the gear. In such a case, if the middle part of the link plate is largely removed like the chain introduced earlier, the gear teeth will easily come off from this removed part when the chain is run in reverse. This idea was devised under the above circumstances, and while it is possible to maintain a high level of shifting performance when operating the transmission, it is also possible to maintain a high level of shifting performance when operating the transmission. The objective is to improve the shape of the link plate of the chain to reduce the chance of the chain coming off the gear it is currently engaged in even if the chain is run in the opposite direction when the line is inclined. do.

[Means to solve the problem]

In order to solve the above problem, this invention takes the following technical measures. That is, in a bicycle chain in which both ends of the left and right inner link plates and both ends of the left and right outer link plates are connected by a pin fitted with a roller, one or both of the inner link plate and the outer link plate are connected. It has a first end portion with a pin insertion hole, a second end portion with a pin insertion hole, and an intermediate portion connecting these two ends, and at least the lower edge of the intermediate portion. To,
A link plate is used that has a concave cutout that is offset toward the front in the chain's running direction.

[Effect]

The center line of the chain entering the multi-stage gear travels tangentially toward the point of contact with the pitch circle of the gear. Therefore, the distance between the center line of the chain and the pitch circle of the gear becomes smaller as it approaches the contact point. When observing the movement of the gear tooth tip relative to the chain in a normal chain, the top of the tooth tip is inclined with respect to the center line of the chain, and is surrounded by the left and right link plates from the front end of the top of the tooth tip. We are entering a space where we can Looking at the above movement from the side, the top of the tooth tip first overlaps the front end of the lower edge of the link plate, and then the entire tooth is accommodated between the left and right link plates. Ru. In the chain of the present invention, at least the lower edge of the link plate, that is, the edge on the side into which the tooth tip of the gear enters, is provided with a concave cutout that is offset toward the front in the running direction of the chain. In other words, when a normal chain attempts to mesh with a gear, the cutout is provided at the location where the gear tooth tips first overlap. This is because, in the chain of the present invention, the tip of the tooth of the gear that is about to engage begins to enter the space surrounded by the link plate later than in a normal chain.In other words, the timing between the centerline of the chain and the pitch of the gear is delayed. This means that the average distance from the point of contact with the circle to the start point of the tooth tip plunge is shorter in the chain of the present invention than in a normal chain. As a result, in the chain of the present invention, the part that enters the gear can be deflected in the lateral direction more easily and to a greater extent than in ordinary chains, and the chain can be smoothly removed from the gear on which it is currently engaged. It becomes like this. Further, since the lower edge of the link plate is initially removed, the lower edge of the link plate easily rides over the tooth tips of the large diameter gear and meshes smoothly with the large diameter gear. For this reason, if the chain of the present invention is used, shifting performance will be maintained at a high level. On the other hand, when the chain travel line between the front gear and the rear gear is inclined, and the chain is made to run in the opposite direction, the situation is opposite to the above-mentioned normal speed change. That is, the tips of the teeth of the gear that rotates in reverse first overlap the lower edge of the link plate at a rearward position.
If the lower edge of the link plate is simply cut out, as in the conventional example introduced earlier, the tooth tips will not overlap until the link plate comes very close to the point of contact with the pitch circle of the gear. The lower edge of the plate becomes easier to separate from the tip of the tooth. However, in the present invention, since the cutout portion provided on the lower edge of the link plate is provided closer to the front in the direction of movement of the chain, a non-cutout portion is left behind the lower edge. Therefore, this uncut portion overlaps the gear tooth tip at a point quite far from the contact point, and this tooth tip suppresses the chain from coming off. Therefore, even if the chain is run in the opposite direction when the chain running line is inclined, it is possible to prevent the chain from being inadvertently disengaged from the gear with which it is currently engaged.

【effect】

As mentioned above, the bicycle chain of the present invention breaks the conventional wisdom of chain link plates that are symmetrical from front to back, and makes the lower edge shape of the chain link plate asymmetrical from front to back, resulting in a difference in the running direction. This system makes good use of the difference in gear shifting efficiency due to the difference in shifting efficiency, and simultaneously improves normal gear shifting efficiency and suppresses chain dislodgement when the chain runs in reverse. Also, if it is acceptable for the chain to come off when running in reverse, reverse the way the chain is attached, i.e.
By reversing the direction of movement of the chain, there is also the effect that the chain speed change efficiency can be selected from two levels, high and low, according to preference.

[Explanation of Examples]

Hereinafter, embodiments of the bicycle chain of the present invention will be described in detail with reference to the drawings. 1 and 2 show a first embodiment of the bicycle chain of the present invention. The structure of the connecting portion of each link plate is similar to that of a conventional bicycle chain. That is, the ends 11a, 11 of the left and right inner link plates (roller link plates) 11, 12
The pin 15, on which the bush 13 and roller 14 are fitted, is inserted in communication between the pin insertion holes provided in the inner link plates 11, 12.
Left and right outer link plates (pin link plates) 1 are attached to both ends of the pin 15 that protrudes outward.
Ends 16a, 16b, 17a, 17b of 6, 17
The inner link plates 11, 12 and the outer link plates 16, 17 are alternately and continuously connected by being press-fitted into the pin insertion holes 18. As each link plate, one having the front shape shown in FIG. 2 is used. In FIG. 2, the right direction is the front in the running direction, and the gear teeth protrude between the left and right link plates from the bottom. In the present invention, the upper edge 1 of the intermediate portion 19 of the link plate
9a and the lower edge 19b, at least the lower edge 1
9b is provided with a concave deletion portion 20 that is offset forward in the running direction of the chain. In the illustrated example, the upper edge 19a of the intermediate portion 19 is also provided with a deleted portion 21 that is offset rearward in the running direction of the chain to make the entire plate 180° symmetrical with respect to its center point, and the chain C is assembled into an automatic machine. When assembling the plates, the step of aligning the plate direction can be omitted. The characteristics of the shape of the link plate according to the present invention are easier to understand when compared with the shape of a general link plate shown in FIG. As a form of the deletion unit 20,
In the example shown in FIG. 2, a gentle oblique side 20a that gradually slopes toward the plate center from the left to the right of the lower edge 19b, and a plate that gradually slopes from the right to the left of the lower edge 19b. It consists of a steep oblique side 20b that slopes relatively steeply toward the center, and the deepest part 20c where the gentle oblique side 20a and the steep oblique side 20b connect is to the right from the left-right center of the plate,
In other words, the chain C is deviated forward in the running direction. However, the shape of the deleted portion 20 may be various other than that, for example, as shown in FIG. 3, it may be a substantially trapezoidal shape that is offset to the right of the plate. Next, the operation of this invention will be specifically explained. FIG. 5 shows a rear gear G consisting of a plurality of gears g1, g2, etc. of different diameters, a guide pulley GP and a tension pulley TP of the rear transmission, and a chain C of the present invention that meshes with these and runs. While the bicycle is running, the rear gear G rotates clockwise and the chain C runs continuously in the direction of arrow F. And the transmission is
By the speed change operation, the guide pulley GP and tension pulley TP are moved in the axial direction of the rear gear G, that is, in the hub axial direction. The chain C of the present invention can be smoothly disengaged from the currently engaged gear when the guide pulley GP is moved in the direction of the hub axis at the entry point to the rear gear G indicated by the symbol A in the figure. Moreover, it can be smoothly meshed with the gear that is about to be engaged. Furthermore, when the running line of the chain C between the front gear and the rear gear G is inclined as shown in FIG.
At the reverse entry portion to the rear gear G, which is indicated by reference numeral B in the figure, the chain C will not be inadvertently disengaged from the gear to which it is currently engaged. FIG. 6 shows details of the entrance portion of the chain C to the gear G, indicated by the symbol A in FIG. 5 above. The chain C runs tangentially with its center line CL heading toward the point of contact with the bit circle D of the gear g. Therefore, since the distance between the center line CL and the bit circle D becomes smaller as it approaches the contact point E, the top of the gear tooth T
is inclined so that its front end Ta is closer to the center line CL than its rear end Tb. Therefore,
As the chain C advances and the gear g rotates, the teeth protrude between the link plates 11 and 12 from the front end Ta of the top thereof. To describe this in more detail, when the top part T of the tooth protrudes between the link plates 11 and 12, the front end thereof
Ta is the lower end 19 of the link plates 11, 12
It first overlaps with the part b closer to the front in the direction of chain travel. However, the chain C of the present invention
In this case, since the concave removed portion 20 is provided at the front side of the lower edge portion 19b, the top portions T of the teeth are located between the link plates 11 and 12 until the link plates 11 and 12 come fairly close to the contact point E. There will be no rush. This means that when the link plates 11 and 12 in FIG. 6 are replaced with the general link plates shown in FIG. 4, the tops of the teeth already overlap the lower edges of the link plates. It will be clearly understood from the fact that it is imagined to be deaf. Furthermore, the above means that even if the link plates 11 and 12 come quite close to the contact point E, they can still deflect laterally without being restricted by the gear teeth, and this also means that the guide pulley GP
This means that when the chain C moves in the hub axis direction, the chain C can be smoothly disengaged from the gear in which it is currently engaged. Then, in substantially the same manner as described above, the removed portion of the link plate passes over the teeth of the gear that is about to engage, thereby completing the replacement of the chain C smoothly. FIG. 7 shows details of the reverse entry portion of the chain C into the gear G, which is indicated by the symbol B in FIG. In this case, a non-cut portion 22 is provided at the rear of the lower edge portion 19b of the link plates 11, 12 in the chain running direction.
remains, so even if the distance from the contact point E' between the pitch circle of gear g and the center line of the chain is the same as the entry point shown in FIG. 6, the rear end of the top T of the gear tooth Tb has already entered the inside of the uncut portion 22. Therefore, chain C becomes difficult to inadvertently disengage from the gear in which it is currently engaged. This effect will be even more pronounced if the tooth side of the gear is chamfered on the outside, or the lower edge of the middle of the link plate is chamfered on the inside. As mentioned above, the bicycle chain of the present invention has
By making a simple change to the shape of the lower edge of the link plate, it is possible to improve the efficiency of gear shifting operations by the transmission, and to prevent the chain from accidentally shifting when the chain is running backwards when the chain running line is inclined. It is possible to simultaneously satisfy two contradictory demands of preventing detachment. In the illustrated example, the characteristic shape of the present invention is adopted for both the inner link plate and the outer link plate, but this shape may be adopted for either the inner link plate or the outer link plate. However, in these cases, it may be adopted for only some of the inner link plates and outer link plates instead of all of them. Regarding the chain, the following cases can be considered as usage modes of the unique shape of the present invention. As shown in the example, the inner link plates 11,1
2 and outer link plates 16 and 17. Parts of the inner link plates 11 and 12, for example every other link plate, are used, and parts of the outer link plates 16 and 17, for example every other link plate, are used. Adopted only for inner link plates 11 and 12. Adopted only in part of the inner link plates 11 and 12. Adopted for all outer link plates 16 and 17 only. It is adopted only in part of the outer link plates 16 and 17. In each of the above cases, this is applied to both the left and right link plates. In each of the above cases, this is applied to the link plates 11 and 16 only on the left side. In each of the above cases, this is applied only to the link plates 12 and 17 on the right side. Furthermore, in the illustrated example, a predetermined cutout is also provided at the rear part of the upper edge of the link plate to make the link plate 180° symmetrical with respect to the center point for convenience in automatic assembly of the chain. The deletion of the upper edge is not particularly necessary for operation, and a flat edge may be used, for example.

[Brief explanation of the drawing]

Fig. 1 is a plan view of one embodiment of the bicycle chain of the present invention, Fig. 2 is a front view thereof, Fig. 3 is a front view showing another embodiment of the link plate, and Fig. 4 is a general link. A front view of the plate, FIGS. 5, 6, and 7 are action explanatory views, and FIG. 8 is an explanatory view of conventional problems. 11, 12... Inner link plate, 11a, 1
2a...first end of inner link plate, 11b,
12b... second end of inner link plate, 14...
...Roller, 15...Pin, 16, 17...Outer link plate, 16a, 17a...First end of outer link plate, 16b, 17b...Second end of outer link plate, 18...Pin insertion Hole, 19...
Middle part, 19a... Upper edge of middle part, 19b...
Lower edge of intermediate portion, 20...deleted part, 22...non-deleted part.

Claims (1)

[Scope of Claim for Utility Model Registration] In a bicycle chain in which both ends of left and right inner link plates and both ends of left and right outer link plates are connected by a pin fitted with a roller, the above-mentioned inner link plate and outer link A part or all of one or both of the plates has a first end portion provided with a pin insertion hole, a second end portion provided with a pin insertion hole, and an intermediate portion connecting these both ends, and this intermediate portion at least the lower edge of the
A bicycle chain characterized by using a link plate having a concave cutout portion offset toward the front in the running direction of the chain.