The Froelich tractor is considered to be the first gasoline-powered tractor, although that’s not entirely true. It also wasn’t a commercial success, so it’s interesting that it’s achieved such a reputation. Here’s the dimensions, specifications, and operation of the Froelich design as near as I can tell.
The tractor was steered from a forward platform, without any seat for the operator. It seems to have been rather wide for just one person, given that there were important levers on either side of the platform. Steering was through a worm gear driving a spur gear on a long shaft. On the end of that shaft was another spur gear which meshed with a chain that attached to the front axle near each wheel. Rotating the wheel thus caused the chain to pull on one side or another of the axle: this axle and the steering mechanism came from the “Robinson & Co” and so is nearly identical to what you’d find on any contemporary steam traction engine.
On the left-hand side of the platform was a long-handled lever which engaged/disengaged the belt pulley. The Waterloo Gasoline Traction Engine Company advertised this point strongly as the belt pulley on a steam traction engine was always engaged when the engine was running. The clutch was probably based on a band brake (to understand my assumption, see this post on John Froelich’s later patented “Reversing Gear and Clutch.”)
On the right-hand side of the platform was a second long-handled lever which was the shifter. Based on the lack of other controls and John Froelich’s 1917 patent for a “Reversing Gear and Clutch,” this lever had to operate as a clutch and gear selector. If we assume the mechanism was similar to his later patent, then it also provided braking. The Froelich tractor had at least a forward and reverse gear. There may have been two forward gears, one that allowed the tractor to reach approximately 2.5mph and the second that allowed it to reach approximately 3.5mph. The Waterloo Gasoline Traction Engine Company advertised the two gears + reverse combination and it appears in some sources for the Froelich design but it could just be confusing the Froelich design with the later production version.
Behind the operator was the main fuel tank. On top of it was a pump handle. As fuel injection wasn’t yet invented and gravity-feed the norm, the solution seemed to be that the pump handle would cause the gasoline to climb up to a reserve tank. As suction from the engine pulled fuel through the line, the suction/siphon effect between the tanks and the engine would keep the engine supplied. The Van Duzen engine did use an early carburetor and ignition was via a hot-tube.
Exhaust was probably routed through an early muffler, the squat horizontal cylinder seen behind the engine in some pictures resembles the one seen in this Van Duzen patent. Engine cooling was through a water jacket. The water tank was located at the rear of the tractor with a pump on top of it. The pump was driven by a belt with the driving pulley attached to a geartrain taken off of the left side of the crankshaft with the axle crossing over to the right side of the engine housing. Some sources describe, and a single replica shows, an open channel returning water to the tank, cooling the used water by evaporation. Most replicas show a closed pipe return.
The one-cylinder, 16hp, vertical engine was located amidships. It was manufactured as a horizontal stationary engine but supposedly shook apart two prototypes when it was mounted horizontally. The engine had a 14in bore and 14in stroke (for 2155ci displacement). The crankshaft and flyarms were partially exposed with a clutch on the crankshaft dis/engaging the belt pulley on the leftside. There were flywheels on each side of the tractor. A large driving pulley transferred power to a smaller driven pulley; the size of those two was different between the original Froelich and the later Waterloo production versions. The driven pulley transferred power into the transmission.
The transmission is something of a mystery. I am convinced there were gears both between the chasis’ main beams and on the outside left side between the left wheel and the main beam. Given the controls, the emphasis on the engine’s ability to reverse, the otherwise lack of brakes, and Froelich’s later patent on a combined reversing clutch and gear, I suspect an early version of his design was somewhere in the transmission.
The final drive was a long axle meshing with the sprockets in the wheels about at the widest horizontal point of the wheel. The final drive axle was either through the main beams or just below, and the main axle sat below those beams. It was another product of Robinson & Co. Both sets of wheels came from the same company.
Froelich Tractor Specifications:
Height: ~129inches (to top of air filter)
Front Wheel: ~32.75inches
Rear Wheel: ~53.125inches