Chain tensioner for bicycle with external chang gear
The utility model relates to the chain tensioning device of outer variable speed bicycle, and more clearly saying so is used to ride rides instead of walk, the chain tensioning device of the outer variable speed bicycle of the outer variable speed bicycle tension chain of the backpedalling brake of sport and body-building or light weight load transportation.
In the past, people are used to ride instead of walk, the outer variable speed bicycle of body-building, amusement or load-carrying, are lock types such as pincerlike lock, common front and rear brake mostly, do not realize the outer speed change of pedal brake bike.Tracing it to its cause, is that outer variable speed bicycle chain is comparatively loose because for speed change.And in backpedalling brake when brake, realize with pin back-pedalling pedal.This moment, top chain was just too loose owing to back-pedalling, and on loose like this chain, drag is very difficult, and easy chain-taking.Therefore, the pedal brake bike in past can not be realized outer speed change.
The purpose of this utility model is to provide a kind of and can eliminates above-mentioned shortcoming, can realize the chain tensioning device of the outer variable speed bicycle of the outer speed change of pedal brake bike.
In order to achieve the above object, the outer variable speed bicycle that the chain tensioning device of the outer variable speed bicycle of the utility model is installed is made of parts such as vehicle frame, front fork, handlebar, front and back wheel, brake, saddle, antero posterior axis, axis and outer variable ratio drive system.Outer variable ratio drive system by pedal, with pedal connect mutually And with pedal drive be installed in crank chain wheel on axis and the vehicle frame, the multistage flywheel that drives with chain wheel ingear chain, with chain engages, be installed in chain can be dialled at the rear derailleur on the flywheels at different levels on the rear axle, be installed in the front chain shifter that chain can be dialled on the vehicle frame on different chain wheels, be installed in the controller of rear derailleur before can controlling on the handlebar and be installed in chain and vehicle frame on chain tensioning device constituted.Above-mentioned crank chain wheel parts can have only a chain wheel, and the different a plurality of chain wheels of tooth number also can be arranged.Above-mentioned flywheel part can have only a flywheel, also can be the cone pulley that the multi-disc flywheel of different tooth numbers is arranged.Thereby can realize the outer speed change of multiple different speed ratios.
The chain tensioning device and the backpedalling brake of the outer variable speed bicycle of the utility model are supporting, are installed on chain and the vehicle frame.Chain tensioning device by with two minor sprockets of chain engages, install minor sprocket support, be installed in little spring on the chainlet wheel shaft of back-end support, the support alives that is assembled together with little spring, be fastened on fixed support on the vehicle frame, link live support and support bracket fastened, the big spring that is assemblied on the axle constituted.Chain tensioning device is used for the outer variable speed bicycle of backpedalling brake.If do not install chain tensioning device, when backpedalling brake brakes, the chain wheel reversing, just top chain can be too lax, backpedalling brake just can't move, and has lost brake function.After using chain tensioning device, because the big tension force of big spring makes support alive fall Xiang Hou Pour.Simultaneously, the tension force of little spring also makes the motion of support conter clockwise, so loose chain will be bent into serpentine, is tensioned again, just can make the backpedalling brake action again, has recovered brake function.Simultaneously, also speed change neatly of the chain of the flexibility of outer variable ratio drive system.Except that chain tensioning device, the remaining part of outer variable ratio drive system can be the structure of using always.The task of the chain tensioning device of the outer variable speed bicycle of the utility model comes to this and finishes.
The chain tensioning device of the outer variable speed bicycle of the utility model has been realized the outer speed change of pedal brake bike, and lower productive costs is arranged.The utility model simple structure, flexible and convenient to use.Can be widely used in moving, body-building, amusement, ride instead of walk, in the outer variable ratio drive system of the outer variable speed bicycle of backpedalling brake of aspect such as transportation.
Below in conjunction with accompanying drawing the utility model is done further explanation.Fig. 1 is the assembling scheme drawing of chain tensioning device of the present utility model.Fixed support 2 is fixed on the vehicle frame 1 among the figure, and the support 3 of living links by axle 4 and fixed support 2, and big spring 9 in tensioning on the axle.The support 3 of living is assembled together by axle 5 with support 7, and in the minor sprocket 6 one and little spring 10 are contained on the chainlet wheel shaft 5 altogether, and another minor sprocket 6 is contained on the support 7.Chain 8 passes two minor sprockets 6, is bent into serpentine to anticlockwise direction under the tension force effect of big spring 9 and little spring 10, promptly is tensioned.
The embodiment of the chain tensioning device of the outer variable speed bicycle of the utility model is as follows.A kind of pedal brake bike has 6 grades of speed changes.Its chain wheel has two kinds of 48 teeth, 36 teeth, and flywheel has 3 of 28 teeth, 20 teeth, 16 teeth.6 gear-stage velocity ratios are respectively 1:3,1:2.4,1:2.25,1:1.8,1:1.71,1:1.28.The utility model chain tensioning device of the outer variable speed bicycle installing of this backpedalling brake is simple in structure, easy to use, flexibility and reliability during the car load speed change, and glancing impact is also very safe.
