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High performance power trains used in current off-highway rubber tire haulage equipment are important to the increased work capability of these machines. Successive innovations and refinements accomplished during the past 50 years to reach the present state of development are reviewed. Advantages obtained during this evolution are noted, and some evaluation is made of contemporary drive means. From this background of achievement, attention is focused on opportunities for further advancements in power trains for such wheeled transport vehicles.

The work tool machines that are discussed are those that have been used to shape the face of the earth and can broadly be described as earthmoving machines. The paper then traces the evolution of drive systems for track-type tractors, motor graders, and loaders (track and wheel), with particular emphasis placed on matching drive systems to the vehicle so that the final result is a useful work tool machine that can be used efficiently in its intended work cycle. Finally, a survey is made of the various drive systems offered by industry today, together with predictions of future drive systems.

One of the basic principles in tire compounding, is to base all compounds on 100 parts (by weight) of rubber hydrocarbon, and relate the addition of all other compounding ingredients to this base of 100-RHC. Regarding tread compounds for agricultural tires, major requirements of a rear tractor tire tread are that it have resistance to abrasion (wear), cleat-tearing, and weathering. With the trend towards larger and higher horsepower tractors, the service-performance demands on tractor tires have increased, necessitating certain design, construction, and compound changes. If this trend continues, further changes will be required, and it is possible that some of the larger tractor tires of the future will more closely approach the present off-the-road type tire.

This paper discusses steels and heat treatments that have and are being used in John Deere tractors. Some of the development test work is described which led to a given selection in three specific cases. Stress levels and other tractor gear design factors are mentioned.

The noise properties of the agricultural farm tractor are discussed. The major noise sources are identified, along with a review of why, how, and to what degree these sources should be controlled. Because of their similarity, the information is also applicable to construction machinery equipment. The control of intake and exhaust noise is dealt with from an overall tractor noise standpoint -- tractor noise being more than just exhaust noise. The conventional air cleaner is treated as a silencing device. Experimental data and analytical methods are presented to substantiate that one must be concerned with the entire exhaust or induction system -- not just the muffler or air cleaner -- to get the optimum benefit from the materials and space used while retaining maximum engine and vehicle performance.

Customer market surveys indicated a need for a larger rubber-tired loader than that which was currently available. They also showed that a dozer was required of the same tractor size which would perform tasks between the heavy bulldozing done by the tracked bulldozer and light grading done by the motor grader. Discussed are the features required of the 988, 5-1/2 yd articulated loader and the 824B articulated bulldozer, the similarities between both machines, and the loader design considerations and the components used. Loader prototypes were built and tested at Caterpillar Proving Grounds and in the field to determine vehicle performance and reliability. Results indicated that two similar machines can be concepted, designed, and built for different applications.

The features, specifications and some of the major design requirements for the new John Deere Industrial Loader-Backhoe units are presented in this paper. The units covered are the JD 300 and JD 400 Tractors with Loaders and 92, 94 and 95 Backhoes.

The story of Power Farming is the great saga of our times. It is a story of free enterprise, perseverance and endurance of the individual, of vision, idealism and cooperation among men, of the lightening of human toil and the release of millions of workers from farms to feed the ever hungry industrial revolution. By no means least, it is the story of producing food necessary to win two global wars, keep our allies alive and millions of the defeated enemy from starvation. FOREWARD By 1915, the Steam Traction Engine had attained its highest development. It was the forerunner, rather than the predecessor, of the farm tractor. The former was the instrument of expansion; the latter, the instrument of progress. The invention of the tractor, following by only sixteen years Otto's practical embodiment application of the Beau de Rochas power cycle to a heat engine, marked the advent of a new order - - the age of Power Farming.

A brief history of the human factors field is given. Methods of obtaining design information in such basic human factors areas as operator size, ride, and control are discussed. The psychological aspects of the interaction between the operator and the earthmover during testing are discussed. The effects of level of motivation, learning, and transfer of training on operator performance are described in terms of laboratory test results.

A deluxe estate tractor is made possible by the installation of a simple hydrostatic drive coupled with precise transmission controls. Simplicity in design provides a compact, high performance and servicable transmission. A single control lever places full control of the vehicle at the operator's finger tips. Ground speed and direction may be varied without varying the engine speed, thereby providing independent auxiliary power at the power take-offs. Safety controls make it possible for unskilled operators to operate the tractor easily and efficiently.

This paper reviews what has happened in the cab industry since earliest developments and defines the “state-of-the-art” at the present time, pointing out areas of design, engineering, and marketing that should be investigated. Some of the new developments in cab design such as pressurization for dust elimination, air conditioning, and noise abatement are discussed.

The mechanics of soils is of fundamental importance in earthmoving and other soil manipulation operations. Future design of machinery for these purposes will make increasing use of this technical discipline. The first step which is to subdivide the soil-machine system into components based upon the phenomena involved is illustrated. The role of soil mechanics is shown and the important areas of study needed to develop design procedures are discussed. Finally, several topics expected to receive increasing attention in the future are considered. The overall objective of the paper is to show the importance of using soil mechanics in machine design and to encourage the further development of the interdisciplinary approach to problems dealing with soil-machine systems.

This report describes equipment designed and built in the Motor Vehicle Devices Testing Facility of the California Highway Patrol, and used to increase laboratory capacity for testing of automotive signal flashers. The new durability test apparatus is capable of handling two or three terminal flashers in groups of 80 at one time, and uses two electronically regulated, solid state power supplies as sources of stable d-c power. The performance test apparatus makes it possible to obtain the operating characteristics of 10 flashers in quick succession through use of a switching control unit and a strip chart recorder.

Increasing numbers of large diameter bearings are being used in turntable-type applications, replacing earlier roller and track and spindle arrangements. This paper aims to acquaint design engineers with the current state-of-the-art in the use of these bearings, with special reference to application in power cranes and shovels, gun turrets, aerial basket devices, utility derricks, and the like. Features of various style bearings are discussed. The equipment designer is provided with guideposts for selecting bearings and for designing suitable bearing mountings.

Design practices and principles for motor truck engine cooling systems are discussed. Major topics covered are: 1. How engine cooling is measured, including correlation of test results to ambient, outdoor and tunnel tests, amount of cooling required including standard versus optional increased cooling, importance of speedability on grade specific levels of cooling to be provided. 2. Heat transfer performance considerations, including the radiator as a heat exchanger, heat transfer theory applied to the engine. 3. Pressure cooling systems, including effect on air-to-boil and metal temperatures. 4. Effect of installation parameters on cooling performance, including grille and fan, selecting radiator core size. 5. Temperature control. 6. Coolant circuit stability considerations, including typical circuits, design criteria and performance of Posi-Temp system for diesels. 7.

A simplified analysis is made of the directional stability of vehicle combinations, such as a tractor combined with one or two semitrailers or a truck and full trailer. Vehicle combinations are treated as linear dynamic systems with two degrees-of-freedom for each unit. The equations of motion are derived considering the influence of braking and acceleration, and a characteristic equation for traveling at constant speed is obtained. The Routh criteria are examined to distinguish between stability and instability, considering oscillatory and aperiodic motions separately. Special attention is given to the behavior of the vehicle during braking, with discussion of the influence of various design parameters and the distribution of the braking forces applied to the wheels. Finally, a new design of fifth wheel device is presented in order to stabilize tractor-semitrailer combinations.

Present and future changes in the trucking industry have, and will, place greater significance on adequate tire inflations to meet increasing service demands. Truck tire inflation monitoring devices over the years have offered promise as one method of insuring, controlling, and maintaining tire inflations. In this connection, both low inflation warning systems and constant inflation systems have been extensively tested and evaluated.

Until recently, dry cargo has been unloaded from trucks by use of compressed air. By making the automotive engine act partly as an air compressor during the unloading operation, the auxiliary air compressor mounted on the tractor frame can be eliminated. This paper, in describing the dual diesel, discusses operating characteristics, cycle analysis, and operational problems.

The Super Pumper System is the world's most powerful land based fire fighting apparatus. It was developed and constructed by Mack Trucks, Inc. from an original concept and preliminary designs prepared by Gibbs & Cox, Inc. It consists of five vehicles. The main vehicle is the Super Pumper which carries a high volume, high pressure pump driven by a lightweight diesel engine. Water from remote sources can be supplied to the other four vehicles, (a super tender and three satellite tenders) providing great flexibility of operation. The system has been in use by the New York City Fire Department for one year. This paper describes the original concept of the system, its development by Mack, and its use by the New York City Fire Department.

Specialists met at the U. S. Army Engineer Waterways Experiment Station (WES) to consider quantitatively various elements of the entire vehicle mobility problem and to suggest an approach for achieving a substantial degree of solution. One specific purpose of the meeting was to design a number of vehicles capable of operating in remote areas of the world where extremely soft soil conditions predominate. Methods of design based on research studies at the WES and at the Land Locomotion Laboratory (LLL), U. S. Army Tank-Automotive Center, were employed to specify tractive component characteristics that would yield the desired soft soil performance. This paper describes the application of the design methods and presents the two wheeled-vehicle concepts and the one tracked-vehicle concept that were evolved to staisfy the basic assumptions.