Improved bridge device

The invention discloses an improved bridge device which comprises an electric connection seat fixedly installed in the wall of a bridge and an electric connection head connected with an electrified maintenance device. The electric connection seat is provided therein with a hollow groove with a mouth facing to the right. The left end wall of the hollow groove is provided therein with left and rightelongated and longitudinally symmetric jacks and a first sliding groove located between the two jacks. The electric connection seat is provided therein with an intercommunication jack and a second sliding groove of the first sliding groove. A pushing groove is further arranged between the first sliding groove and the jacks. A sliding block is slidably mounted in the first sliding groove. The leftend of the sliding block is provided with a through groove that communicates in the up and down direction. The left end face of the sliding block is provided with longitudinally symmetric first oblique contact heads. A pushin