Patent ID: 8904776

Claim:
A cylinder driving apparatus using air pressure including a plurality of flexible tubes 2 installed in the interior of a casing 1 and being flexible with the aid of high pressure air, a connecting rod 3 which is fixed to each flexible tube 2 and passes through the upper side of the casing 1 , a crank shaft which is sequentially engaged to the connecting rod 3 and rotates with the aid of an elevation operation of the connecting rod 3 , and a high pressure tank 6 supplying high pressure air to the flexible tube 2 via an air line 5 , comprising: a valve 8 which is installed partitioning the interior of the flexible tube 2 into upper and lower spaces, thus opening and shutting the flow of air into the upper and lower spaces, said valve 8 remaining blocked so as to block the upper and lower spaces when the flexible tube 2 is filled with high pressure air and being opened when the flexible tube 2 reaches the top dead point; and an assistant tube 7 which has a tensile spring 9 a in its interior, thus having a spring force serving to maintain a compressed state and a connection to the valve 8 , so the compressed air of the flexible tube 2 is moved to the assistant tube 7 when the valve 8 is opened.