The Bates "Steel Mule. '
Page 7
Page 8
If you've noticed an error in this article please click here to report it so we can fix it.
By Henry Sturmey.
A couple of years since I described in these pages an American tractor which was designed to hitch on to any agricultural machine, or vehicle, taking the place of the horse and being steered by reins from the seat of the towed vehicle. That inventor had certainly got the germs of an idea which appeals to the imagination as the desirable thing, but his price£525—was too high. The Joliet Oil Tractor Co., one of the oldest and largest firms in America in the oilengine-propelled tractor business, has now, however, developed a machine embodying the same basic idea, but possessing several entirely novel features of merit, and listing, over there, at the not unreasonable price of 2180, which is worth con sideration. •
It is called the Bates "Steel Mule," and is designed to take the place Of horses for pulling the implementsused in tilling the land and for farm work generally. In principle, a heavy-duty four-cylinder tractor motor is mounted on a frame, and gives traction to a caterpillar device—which the makers terra an " apron " or "crawler "on the ground, which allows the tractor to be used on ploughed ground when the soil is being harrowed and disced. It further provided that the ground pressure or this crawler is automatically increased with the pull of the load, whilst the driver, instead of sitting on the tractor, sits on the wagon or implement and controls the tractor as well as the implement, thus enabling the work to be done by one man.
The engine is a four-cylinder one, 41 in. bore by ei in. stroke, and
every precaution has been taken to protect it from dust. It is governed by a centrifugal ball governor, fired by high-tension magneto ignition and cooled by a centrifugal pump circulating the water through a large tubular radiator mounted in the front of the machine. Transmission is by large chrome-vanadium cut gears running in an oil bath, and two speeds and reverse are provided for, giving travelling speeds of ak and 2-1m.p.h., with 2 m.p.h. reverse. A belt pulley is provided with 8 in. by 81 in. face, arranged to run at 830 r.p.m. and a belt h.p., for driving fixed machinery, is claimed exceeding 30 h.p.
Power, is conveyed to the " crawler " by a large nickel-steel roller chain having sprockets -with large bearing surface, both sprockets and chain running in an oil-bath, with dust-proof casing. A draw-bar pull of over 13 h.p., is claimed, and a particular feature of the machine is the spring-mounted oscillating arrangement of the crawler mounting and the "compound lever hitch," by means of which, not only is the crawler, through which the drive is taken, enabled to -negotiate the most uneven grtund-1 and to crawl over obstacles of all kinds without difficulty, but the tractive, pressure of the crawler upon the ground is, over and above that exerted by direct weight, increased by the pull of the load, so that the machine does not depend on its weight to get its traction, thus avoiding excessive weight and consequent " packing " of the ground. As the implement drawn encounters increased resiktance, the tractive pressure on the ground of the apron
is increased to a corresponding and compensatory degree.
The crawler, or travelling 'chainbelt, is mounted in a frame which is hinged at its rearmost end and controlled centrally by heavy coil springs encased in steel shells. These springs absorb all road vibration and jar, and thus protect the more delicite machinery. Of the power plant and render the machine suitable for road as well as fixed work and prolong its life generally. The one gearwheel and three idlers which control and operate the crawler are each keyed to large revolving shafts, and the ends of these shafts run in large adjustable dust-proof bearings located in the steel side frames and each being independently lubricated. The entire mechanism of the crawler is so assembled that the shafts cannot get out of alignment, and it is claimed that, whilst an ordinary wheel cannot get traction on rough ground and an ordinary " caterpillar" type of drive, if rigidly connected with the main frame, will rear up in front, even to the extent of upsetting, this flexible apron drive with its oscillating support accommodates itself to the uneven ground independently of the main frame and that the rise and fail of the front wheels does not aftect the contact of the crawler with the ground, whilst uneven travel on the part of the latter has no effect on the steering, giving the machine, as a whole, perfect flexi bility under all conditions. The apron is stated to be made of a very high quality of material so as to enable it to withstand the wearing action of dust, whilst all the bearings of it are dust-protected.
The great feature of novelty and value about this unique driving mechanism is what is termed the "Compound Lever Hitch." Instead of the draw-bar being attached to a portion of the solid rigid frame of the tractor, it is fastened to the oscillating steel side frames of the crawler, with the result that the pull exerted by the load, being forward of and below the hinge-joint attaching the crawler to the main frame; tends to pull down the front of the apron and press it into the ground, The weight of the rear of the tractor resting on the rear portion of the crawler frame prevents its digging its nose into the ground and keeps it, level. It will thus be seen that the weight of the tractor is not a necessary factor in securing tractive effect. Under ordinary conditions of light loads, the springs give the necessary downward push to give traction to the " Steel Mule," even when pulling no load at all, and the traction increases as the necessity for it increases. The power on the draw-bar is claimed to he equal to that exerted by a team of six good horses, yet the weight of the machine complete is less than 43 cwt., and the ground pressure on the driving apron is about 4 lb, per sq. in., or less than that exerted by the average man standing on one foot. This seems to me an extremely valuable feature.
The "Mule" is supported for ward on two steering wheels, 30 in. diameter and 7 in. face. These wheels are mounted in forks which are adjustable as regards tread, or distance apart, from 3 ft. 91 ins, to 6 ft. 91 ins., an arrangement which allows for cultivating rows varying in width from 36 ins. to 48 ins. The general dimensions of the machine are 11 ft. long, 8 ft. 8 ins, wide, and 6 ft. high, and the shortest turning radius is 8 ft. 9 inh. Thirty-eight inches ground clearance is given, and the machine is steered and controlled by means of a long horizontal steering post and wheel carrying the controls, which is mounted at the hack and projects rearwards, so that when the farm cart or implement is hitched up, the steering and control wheels are conveniently placed in front of the driver sitting in the seat of the implement, or vehicle drawn, and two sets of steering gear are provided of different lengths, so that the machine may be in this respect adapted to the implement it is drawing and to the position of the seat carried upon it. .Whilst the oscillating lever-hitch device is a recent addition, this " Steel Mule " has been a commercial article for several seasons, about 1000 users in America having them, and the company tell me they are now turning them out at the rate of about 100 per month, so that it would appear to be, as it looks, a thoroughly " practical machine.