Ohio Tractor

Clutch and Transmission Assembly of Ohio Tractor

Fig 101 : Clutch and Transmission Assembly of Ohio Tractor.

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9915 Trent Avenue Spokane, WA 99206

The following write up and drawings of the old Ohio tractor are taken from the 1914 book, The Modern Gas Tractor, also from the March 1912 issue of Gas Power Magazine.

My uncle, August Harsch, owned one of these big Ohio tractors. He bought it used in about 1913 or 1914 when he was farming in Alberta.

I do not know what my uncle ever accomplished with it, but by 1920 it was sitting idle, all by itself in a sandy field surrounded by scrub trees, many miles from the nearest town.

We visited this old tractor many times during the 1930's but never took a picture of it. The last time we saw it was in 1936. It was complete then and looked like it could be run, with all fuel and water tanks intact and in place.

This was the only Ohio that I have ever seen and I have never heard of another one anywhere. If there was one left anywhere in the U. S. or Canada I would surely make a trip just to see one again.... anyone having such a tractor, please welcome a visitor from Washington State.

A study of the drawings of the Ohio show that the power plant along with the trucks were quite well engineered by 1912 standards, but the small spinning roller friction drive wheels must have been a musical dream when the tractor was in motion, and a nightmare when worn out of adjustment.

No power starting is shown nor mentioned. Most likely it was started by turning the flywheel forward and, if so, with a five shaft gearing layout. Final drive would probably be an internal bull gear and pinion arrangement.

The high narrow cooling tower suggest that this may have been a dry or partially dry water cooler, with reserve water stored in one or more tanks.

The tractor was equipped with roller friction power steering.

Hopefully someone out there in Engine land will come up with more information on this old time beauty, that was designed, built, sold and disappeared all in the space of a few years.

Any suggestions, news or corrections would be interesting to all tractor collectors, and to the folks at Poverty Flats, E. 9915 Trent Avenue, Spokane, Washington, 99206.

Another form of friction clutch in which a friction wheel is employed is shown at Figs. 101 and 102. The view of the mechanism at Fig. 101 shows clearly the mounting of the friction wheels for driving a movable cross shaft, which in this case is parallel with the engine crank shaft. This main driving shaft, which extends across the frame, is provided with a friction driving wheel at each end and carries a pair of sliding gears which may be engaged with either one or two gears on the transmission cross shaft placed immediately back of the main driving shaft that carries the friction wheels. The gears on the transmission cross shaft are of different diameters, one being smaller than the other, as is true of the sliding gears on the squared main shaft. Before discussing the method of obtaining speed changes or final drive it will be well to consider the action of the friction rollers.

The engine carries two large flywheel members, which are so arranged, one at each side of the frame, that the friction wheels employed for driving fit in an annular channel machined between the inner and outer fly-wheel members. This is clearly shown at Fig. 102-A. The flywheel hub is enlarged and forms one driving member while the fly-wheel rim, which has a smooth and true inner periphery, forms the other driving member. When the friction driving wheels carried by the transmission main shaft are in the neutral position they are in the space between the inner and outer fly-wheel driving members, and as the friction roller is not in contact with either the hub or the rim of the fly-wheel, one member may revolve independently of the other.

Also the combination tractor-roller, and our tractor hay baler on which we use our friction drive when baling hay or when running over the road. Leader steam engines and separators so favorably known for 25 years, are the goods we manufacture. Caption from an Ohio Tractor Mfg. ad in March, 1912 Gas Power

To obtain the forward drive, the main shaft is rocked so the friction wheels are brought in contact with the inside of the fly-wheel rim. If this is turning in the direction indicated by the arrow, it will turn the friction roller in the same direction, and the main shaft is revolving in the same direction as the motor crank shaft. To obtain a reverse motion of the main shaft the friction rollers are disengaged from the interior of the flywheel rim and are pushed against the exterior of the fly-wheel hub, as indicated at C. This will produce a motion of the main shaft opposite in direction to that of the crank shaft. The leverage is proportioned so that very little pressure is necessary at the operating lever to insure positive drive. The shaft on which the friction pulleys are keyed is hung on pivoted or eccentric bearings, which are located in such a way that when the friction surfaces are brought in contact with each other they will automatically produce pressure enough to move the load, and as the resistance augments the driving pressure becomes stronger and the rolls can transmit the full amount of power generated by the engine. The friction wheels are made of paper or straw-board fiber and may be very easily replaced when worn.

It is claimed that the friction drive methods cannot be compared to the friction clutch because it will give a much smoother and more flexible drive than is possible with any form of friction clutch. It is contended that the clutch is too positive a lock between the driving and driven parts, while the friction rollers are not so positive in their action. It is also advanced that in event of sudden shock the friction roller will slip to some extent, while with the friction clutch, which is positively locked, a sudden strain will result in breaking a gear or stressing of some of the transmission parts. With either of the friction drives described, a one-lever clutch control is obtained and one can start, stop, or reverse the tractor instantly by using but one control lever.

The methods of obtaining the changes of speed on the Ohio tractor may be easily understood by referring to illustration, Fig. 101. If the sliding gears are shifted along the main shaft, so that the smallest pinion on the main shaft is in mesh with the largest gear on the transmission cross shaft the slowest rear-wheel speed is obtained. If the largest pinion on the main shaft is slid into engagement with the smallest gear on the transmission cross shaft the highest rear-wheel speed will be obtained. If the sliding-gear member on the main shaft is placed at a neutral position so that it is not in mesh with either gear on the cross shaft, engaging the friction wheels and the fly-wheel will not produce motion of the tractor. The drive from the transmission cross shaft is by a pinion which engages a large gear attached to the differential spider. The differential gear is attached to a cross shaft to which the bull pinions, which drive the bull gears on the rear wheels, are attached. It will be apparent that with the friction roll clutch it will be possible to obtain the same number of speeds on the reverse drive as when the tractor is moving ahead.