IC Engine

Popular Science Magazine (August 1926)

"Amazing New Motor Runs without Crankshaft or Gears"

Possible revolutionizing of the production of gasoline motors is seen in the invention of an amazing type of engine that recently made a successful airplane test flight at Farmingdale, LI. Its inventor is Harold Caminez, formerly of the Engine Design Section, US Army Air Service.

Internally, the novel motor is constructed along radically different lines from other aircraft engines. There is no crankshaft. Nor are there timing gears.

In place of the usual crankshaft there a plain, straight shaft on which is mounted a large steel cam that is shaped like a figure 8. It is placed directly in line with the centers of the cylinders so that it engages with roller bearings mounted in each piston. These roller bearings are specially built with large diameter outer races. Four lightweight connecting rods or links are so arranged on bearings in each piston that when the cam pushes the pistons in two of the cylinders toward the cylinder head, the links pull the other two pistons down and keep the roller bearings in them in contact with the cam. These links are far lighter than the connecting rods in the ordinary engine, because their only function is to pull the piston down on the intake stroke and they consequently do not have to bear any of the strain of the power stroke.

Gasoline engines of the modern type develop the most power when they are run at high speed, higher in fact than is desirable for best efficiency with an airplane propeller. The new Caminez engine takes care of this difficulty in a most ingenious way. Because the cam is made like a figure 8 the pistons make two complete strokes up and down for each revolution of the shaft on which the cam is mounted. In an ordinary engine, the pistons make one stroke up and down for each revolution of the crankshaft. In other words, the shaft of the new engine revolves at half the usual speed. This means high and efficient speed for the pistons combined with the most desirable speed for the air propeller.

Incidentally, this doubling up of the piston strokes means that no gears are needed to run a camshaft to operate the overhead valves. The main shaft of the Caminez engine turns at the same speed in relation to the piston movements as does the camshaft in the ordinary motor. He new engine therefore gets along without camshaft or gears to drive it.

But of still more importance from the point of view of durability and smoothness of running is the fact that the new engine is the first four-cylinder motor that is inherently balanced mechanically so that there is no vibration caused by the moving parts.

Figure 1: Showing the Figure-8 Shaped cam, which is rotated by round bearings mounted in each piston, eliminating the crankshaft ~

US Patent 1,714,847

"Internal Combustion Engine"

Harold Caminez

(28 May 1929)