includes a pair of slide plates 51 and a shaft 52 each of the slide plates 51 is defined with a slot 511 the slides plates 51 are oppositely arranged in corresponding way and then a pair of bolts 53 are used to make the movable arm 30 slidably connect to the front cantilever 40 and thus the bolts 52 are able to slide within the slot 511 the shaft 52 is slidably disposed between the two bolts 52 based on the above mentioned structure the wheelchair in accordance with the present invention is able to roll over barriers 60 easily and smoothly when running on level road the front jockey wheel 41 and the driving wheel 31 keep contacting the ground however as shown in fig5 and 6 initially the front jockey wheel 41 will contact the sloping surface 61 of the barrier 60 upon encountering a barrier 60 and is stopped by the surface 61 as shown fig5 at this moment the driving wheel 31 keeps driving the wheelchair to move forward with the pushing force generated by the driving wheel 31 the front jockey wheel 41 and the front cantilever 40 will rise upward smoothly and then via the sliding assembly 50 the front cantilever 40.