Clark-Michigan is a name more commonly known to New Zealand contractors for its range of wheel loaders rather than motor scrapers.
However the Michigan range of conventional and elevating scrapers have been around since the early 1960s in various sizes although very few were imported into New Zealand.
Our subject, the Michigan 110-15, was first introduced in 1972 and was a derivative of the earlier model 110-11.
The 110-15 was also available as a twin engined machine and in this configuration it was known as the model 110-HT. This machine is beyond the scope of this month’s feature and will be the subject of an upcoming article.
Powered by a 225 horsepower General Motors Detroit Diesel 6V-71T turbocharged V6 diesel engine, this was connected to a Clark 9-speed powershift transmission which gave the 110-15 a useful range of travel speeds.
A special low first gear was provided for loading which distributed the most efficient mix of power to the drive wheels while at the same time ensuring that the elevator pump was providing maximum output.
In top gear the 110-15 could motor along at 35 mph.
The all Clark drivetrain included a limited slip differential, and a first for an elevating scraper of this size – a suspended front axle to improve the riding qualities of the machine at speed.
This consisted of two trailing arms, two suspension cylinders and an accumulator, all of which allowed the front axle to oscillate while at the same time absorbing haul road shocks.
The beauty of Michigan’s axle suspension was that it kept the extra weight the system incurred quite low, maintaining a low centre of gravity for the machine
Michigan called this system Hydra-Ride and it was subsequently fitted to other scrapers in the Michigan range.
Terex also thought the Hydra-Ride was a good idea and incorporated it into its “Loadrunner” series of scrapers.
In place of the usual S-cam shoe brakes, the Michigan 110-15 utilised disc brakes all round which gave the machine improved stopping capabilities over its contemporaries.
Steering was effected by two hydraulic rams mounted high on the gooseneck and gave the machine 90° turns to left or right.
The fitting of a ROPS did not interfere with the turning circle of the machine.
For the operator all the controls were handily positioned for ease of use and visibility was quite good. During loading the operator normally looked over his right shoulder and in this position visibility to the cutting edge was very good.
A range of optional elevator speeds could be selected to best cope with the material being loaded rather than the two speeds that were usually offered by other manufacturers.
In terms of creature comforts, the 110-15 could be fitted with a fully enclosed cab with heater or open ROPS structure depending on requirements.
All the vital instruments were grouped together on a panel to the operators right and an air suspension seat was standard equipment.
The bowl of the 110-15 was designed and manufactured by Hancock (by now a subsidiary of Clark-Michigan) and was rated at 15 cubic yards heaped capacity.
It featured the usual Hancock trademarks of a fixed cutting edge with sliding floor and doze out ejector.
The bowl was constructed of box section channels welded together and presented a very clean, modern appearance.
For tough loading materials four bolt-on teeth could be fitted to the centre cutting edge.
A variable displacement pump supplied hydraulic power to the hydraulic elevator motor which operated at a speed from 0 to 276 feet per minute depending on operator selection.
The elevator was of conventional construction and had 18 flights of 9’ 8” width.
Although not sold in great quantities the Michigan 110-15 was a very capable elevating scraper and popular with those who used it.
Clark-Michigan discontinued all scraper production in 1981 and have not ventured back into this area.
The New Zealand Connection.
The New Zealand Ministry of Works (as it was then) imported five Michigan 110-15 elevating scrapers in 1973 through the Michigan franchise holder of the day Andrews & Beavan.
These operated mainly in the North Island, their first job being on the expansion of Mangere Airport in Auckland and subsequently on to other jobs.
Disposal of these machines through Government Stores Board auction released them into the hands of private contractors in the early 1980s and most are still operational.
Brief Specifications – Michigan 110-15
Engine: GM 6V-71T, turbocharged V6 cylinder, 225 horsepower
Transmission: Clark 9-speed powershift
Brakes: Self-adjusting caliper discs on all wheels
Steering: Full hydraulic, 90° to either side
Top Speed: 35 mph
Capacity: 15 cubic yards
Elevator: Infinitely variable hydraulic motor
Width: 9’ 6”
Height: 10’ 1”
Operating Weight: 20.7 tons (empty), 36.8 tons (loaded)