in order to help people achieving the effect of exercise indoors , the present invention proposes an auxiliary supporting device of a bicycle . as shown in fig4 , 5 and 6 , an auxiliary supporting device 50 comprises a base 502 with a main rotating shaft 503 . the main rotating shaft 503 has a protruding part 504 , and a rear wheel 602 of a bicycle 60 is engaged on the protruding part 504 . two rolling elements 506 are disposed on the base 60 and located below the protruding part 504 such that rear wheel 602 of the bicycle 60 is located on the rolling elements 506 . the main rotating shaft 503 has also a supporting element 508 . the supporting element 508 includes a rotating element connected with a rolling element 510 for engaging a front wheel 604 of the bicycle 60 such that front wheel 604 is located on the rolling element 510 . the main rotating shaft 503 can be either free rotated to let bicycle 60 sway ( as shown in fig7 ( a ) and 7 ( b ), the bicycle 60 can swing along the axle of the main rotating shaft 503 .) or fixed by a fixing element 512 like a tenon joint such that it cannot rotate . the fix element 512 can be applied in the cases : ( 1 ). when the bicycle 60 is not in use , the main rotating shaft 503 is fixed to prevent the bicycle 60 from falling down . ( 2 ). it also can be used to train a user who cannot ride bicycle to move the pedals of the bicycle 60 without worrying bicycle 60 falls down . in addition to the function of bicycle 60 swing along the axle of main rotating shaft 503 , the supporting element 508 can also be engaged with the main rotating shaft 503 via a bearing 516 so as to rotate along the direction perpendicular to the main rotating shaft 503 , thereby making the handlebars of the bicycle 60 be able to turn left and right . besides , the rolling element 510 is connected to the rolling elements 506 via a rotating guide wire 514 . the rolling elements 506 and 510 are rollers . when a user moves the pedals of the bicycle 60 , the rear wheel 602 leads the rolling elements 506 to roll and further drives the rotating element 510 to rotate through a rotating guide wire 514 so as to let the front wheel rotate therewith , thereby accomplishing synchronous rotation of the front and rear wheels . as shown in fig8 , the rear wheel 602 of the bicycle 60 is supported by the two rolling elements 506 , and the engagement between the rear wheel of the bicycle 60 and the protruding part 504 is accomplished by means of piston and bushing ( the engagement between the front wheel axle of the bicycle 60 and the supporting element 508 is also accomplished by means of piston 518 and bushing 520 , as shown in fig9 ) such that the weight of a rider and the bicycle 60 can be directly transmitted to the rolling elements 506 . the rear wheel 602 of the bicycle 60 rotates to lead the rolling elements 506 to roll . the roughness degree of the surface of the rolling elements 506 makes the rider feel as though he is rides on the road . to sum up , when a rider uses this auxiliary supporting device of a bicycle ( with not fixed by a fixing element 512 ), the principle of the bicycle 60 won &# 39 ; t fall down is the same as that of riding a bicycle on the road . they both exploit the moment of inertia generated through rotation of the front and rear wheels . the present invention utilizes the rotation of the rear wheel of the bicycle to lead the rolling elements to roll and further drives the front wheel to rotate via the rotating guide wire and front wheel rolling element . by this auxiliary supporting device of a bicycle , the bicycle can swing and the handlebars of the bicycle can turn left and right . therefore , the user can simulate the exercise of riding bicycle at a fixed location . although the present invention has been described with reference to the preferred embodiment thereof , it will be understood that the invention is not limited to the details thereof . various substitutions and modifications have been suggested in the foregoing description , and other will occur to those of ordinary skill in the art . therefore , all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims .
an auxiliary supporting device is designed for supporting and fixing a bicycle . when a user rides a bicycle which is set up on this supporting device , the bicycle will neither move forward nor fall down if the user applies the skill of riding bicycle . this device can be used to train a rider for better bicycle controllability or to let user exercise at a fixed location .