Close speed regulation is maintained by a throttling type governor. The voluntary speed variation used to slow the engine down to meet certain conditions encountered in plowing is accomplished by a small lever located at the end of the cylinders. The cooling water is circulated through the cylinders by a gear driven centrifugal pump. From the cylinders the water enters a closed radiator of the automobile type located at the front of the traction where it is cooled without loss. A nine feed, forced type oiler is used which supplies oil to the cylinders and bearings, and also to the transmission gears. External bearings which are subjected to dust are equipped with grease cups. The fuel pump which takes its supply from an 80 gallon tank is in an accessible position near the operator and is provided with a handle by which it is operated when starting the engine.
The clutch which is located in the flywheel at the right of the engine is operated by a lever on the footboard. All of the friction faces and levers are arranged inside of the pulley so that they are not only protected from injury but are prevented from tearing the belt should it slip from the pulley face.
A powerful foot with a drum on the differential gear will hold the outfit on a grade independent of the engine.
The transmission is of the shifting gear type with hardened steel gears. The transmission gears are enclosed in a practically dust proof case, this being connected with enclosed crank case and better providing for air displacement of the pistons. Power is transmitted to the truck through the clutch on the left hand side of the engine, which is operated by combined clutch and shifting lever on the footboard. This lever has an interlocking device, arranged so that it is impossible for the operator to shift the gears before the clutch is disengaged, or to engage the clutch until the gears are completely in mesh. It is also impossible to get two sets of gearing in mesh at one time and prevents any possibility of stripping gears by applying the load on the corners of the teeth.
The drive wheels are 78″ diameter, 30″ face. These give a very large bearing on the ground which is particularly desirable when using the engine for cultivating or seeding on plowed ground. The front wheels are 48″ in diameter, 14″ face. The wheel base is long and engine is easy to guide. The drive wheels are covered by a metal housing which protects the operator and the working parts of the engine from dust and mud.
This engine gives a drawbar pull on low gear of 9,000 lbs., which will haul from 8 to 12–14″ plows, according to the character of the plowing. The hitch is placed about 18″ above the ground and consists of a heavy bar extending approximately to the middle of the bull wheels on each side, thus providing for hitching the load most satisfactorily.
(145) The Rumely “Oil Pull” Tractor.
The Rumely oil-pull tractor is driven by a two cylinder, four stroke cycle oil engine, having a bore and stroke of 10 × 12 inches giving 30 tractive horse-power and 60 horse-power at the pulley. The cylinders are cast single and are provided with independent heads. The pistons are easily removed by unbolting the cylinder heads and the crank end of the connecting rod, after which operation they may be pulled out upon the platform. The exhaust and inlet valves are in easily removable cages placed on either side of the cylinder. The stems of the valves are at right angles to the bore of the cylinder and open directly into the combustion chamber without pockets or extensions to the chamber.
A bell crank rocker arm acts on the valve stems which in turn is actuated through a push rod that extends from the cam-shaft in the crank chamber. The cam-shaft, rocker arms, valves, and half time gears are clearly shown by Fig. 128. The housings of the inlet valves connect directly with the special kerosene carburetor made by the Rumely Company. The Higgins carburetor used on these engines is very simple and effective in vaporizing the heavier fuels and has no springs nor internal mechanism to get out of order. The carburetor is controlled directly from the governor which regulates the air, water and kerosene required for the combustion, and has no manual adjustments that need attention from the operator. A constant flow of kerosene and water is maintained through the carburetor by means of force pumps, the level in the device being kept constant by overflow pipes through which the excess returns to the supply tanks.
