Oscillating piston engine

An oscillating piston engine comprising:

• a gas-exhaust end cover having an oil injection hole, an exhaust disc valve mounted atop on an upper cylinder cover with gas tightness and driven by an exhaust gear formed atop on a gas in-and-out control shaft which is lowerly engaged with an intersecting power transmission shaft, and said upper cylinder cover formed with four gas exhaust holes;
• each separated in equal radians;
• a cylinder body having two kidney-like cylinders formed diagonally inside said cylinder body, each kidney-like cylinder having two combustion chambers provided with spark plugs and gas passages from a carburetor, and having two symmetrical internal extensions each formed with several expansion-plate grooves for inserting expansion plates and springs therein for gas tightness;
• a wing-shaped piston symmetrically formed with two extensions on both sides each inserted with expansion plates and springs into grooves formed thereon;
• a lower cylinder cover formed with four gas-inlet holes thereon;
• a gas-inlet disc valve mounted under said lower cylinder cover and engaged with an inlet gear driven by said gas in-and-out control shaft;
• an inlet end cover formed under said inlet disc valve and formed with a gas inlet to connect to a carburetor;
• a wing-shaped spring plate engaged with a spline shaft formed under said piston and oscillatingly impacting on both sides of an arcuated rebound block formed on a casing;
• a bevel gear formed on the spline shaft of said piston and alternatively engaged with a pair of sector bevel gears separately formed on a power transmission shaft;
• a fly wheel connected to said power transmission shaft and engaged with a starting motor;
• and
• a casing covering the rotary engine, each of said pair of sector bevel gears formed as a semi-circle and formed with two open cutting ends of which one cutting end of one sector gear is separated from another cutting end of another sector gear with an acute angle when projectively viewed along said transmission shaft, whereby the rotation of said piston in one direction will drive said transmission shaft for rotary motion as said bevel gear under said piston engages with one sector bevel gear on said transmission shaft, and counter rotation of said piston will still drive said transmission shaft in the same rotary motion as said bevel gear under said piston engages with another sector bevel gear on said transmission shaft so as to convert the oscillating motion of said piston into a continuous rotary motion of said transmission shaft.