The Allis-Chalmers 645 loader
Notable as Allis-Chambers’ most successful wheel loader, 1000 645s were purchased by the US Military in the mid-1960s and were their standard medium wheel loader for some considerable time. BY RICHARD CAMPBELL
WHILE ALLIS-CHALMERS was responsible for a lot of ‘firsts’ in the track type tractor industry, it tended to be somewhat of a follower when it came to wheel loaders.
However, when it introduced its first articulated wheel loader, the model TL- 645, it was a real beauty and fully justified all the research and development that Allis-Chalmers had put into it.
Introduced in 1965 after a five-year testing period, the model 645 was a medium-sized machine with a 2.5 cubic yard bucket, suited for all manner of applications, be it construction, aggregate handling, industrial or if equipped with log forks, forestry.
A little background
In the late 1940s, the Tractomotive Corporation of Deerfield, Illinois was manufacturing small rigid frame, rear wheel steer loaders using Allis-Chalmers agricultural tractors as a chassis.
These loaders were very efficient and second only to Hough’s wheel loaders in popularity.
Tractomotive also built hydraulic rippers, pipelayer attachments and complete loader packages that were fitted to Allis-Chalmers track type tractors.
Allis-Chalmers track type tractors with Tractomotive loaders fitted to them were identified by the suffix G in their model number designation eg, HD-6G, HD-9G, HD-11G etc.
This marriage of convenience was so successful that Allis-Chalmers decided to buy the Tractomotive Corporation outright in 1959.
By the 1960s several of Allis-Chalmers’ competitors were introducing articulated steer machines into their product ranges and these loaders were taking off in a big way, impinging on Allis-Chalmers’ wheel loader sales.
The decision was made to launch the 645 by Allis-Chalmers management after successful testing of prototypes on a number of job sites.
For several years after its introduction, the wheel loader was known as the TL-645 in homage to its designers, Tractomotive Corp.
This designation was quietly removed after 1967.
Power was provided by an Allis- Chalmers model 3500 six-cylinder, turbocharged diesel putting out 150 flywheel horsepower and connected to an Allison 2-speed powershift transmission with high and low ranges, effectively giving four speeds forward and reverse.
Nominal bucket size was 2.5 cubic yards but smaller or larger sizes (up to 3.5 cubic yards) could be fitted depending on material density.
A notable feature of the 645 was the steering angle, which exceeded that of all its competitors.
Allis-Chalmers’ main competitors (Michigan, Hough & Caterpillar) all had 40 degree steering to either side whereas the 645’s steering angle went to 45 degrees either side of centre.
In this form, the 645 was manufactured up to 1972 when an upgrade of the design was undertaken.
Principal changes included a new engine, the model 3500-II and the introduction of Allison’s new “soft-shift” modulated transmission.
Bucket capacities and tipping loads remained the same.
Throughout the upheaval of the Fiat buy up, the 645B continued in production (as the Fiat-Allis 645B) and was finally declared obsolete in 1981 after some 6200 had been produced.
The model 645/645B was the most successful and numerous wheel loader ever manufactured by Allis-Chalmers.
The United States Military purchased over 1000 Allis-Chalmers 645s during the mid-1960s and it was for some considerable time, their standard medium wheel loader.
From the useless information department
Allis-Chalmers 645s were only painted in the company’s original “Persian Orange” colour during the first six months of production, all subsequent machines leaving the factory in “Hiway Yellow”.
Addenda
Following the roll-out of the 645 in 1965, a slightly smaller machine, the 545 was added to the range later that same year, and in 1967 the larger model 745 was put into production (the model 545 was redesignated the 605 in 1971).
The last Allis-Chalmers articulated steer loader to appear was the huge model 945 in 1973.
The Model 645B loader described
As mentioned earlier, the original Allis-Chalmers 645 was powered by an Allis-Chalmers model 3500 6-cylinder diesel.
A change was made to the engine’s fuel system in 1972 with the discontinuance of the previously used Roosa-Master fuel injection system, replaced by a Simms system.
In this configuration the engine produced 158 flywheel horsepower, slightly up on the previous engine.
Allison provided the powershift transmission, a twin-turbine “soft-shift” TT series which gave the 645B a top speed of around 23mph (37kph).
Brakes were full air operated shoe type with a Cardon-shaft park brake.
Articulation point was in the dead centre of the machine.
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