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An electronic information system has been devised to minimize problems of communication in the engineering field as they apply to the testing of industrial equipment. The paper describes a communication system that makes use of telemetry for data gathering, magnetic tape and analog computers for data reduction, a single-sheet engineering memo as the input form, and a standardized five-copy print-out specification form that gives a complete history of problem areas encountered in the program.

This paper provides an overview of the current state of knowledge on medium and heavy truck safety and reviews the results of truck safety research sponsored by the Motor Vehicle Manufacturers Association. A number of issues have been raised about the accident experience of trucks, and the injuries and fatalities sustained by occupants. The diverse viewpoints and perceptions which exist on the reasons for these accidents and what countermeasures should be taken are reviewed. The evolutionary nature of truck accident research is presented, pointing out that sufficient detailed accident and injury data are lacking. Corresponding information on truck configuration, size, weight and exposure data remain inadequate. The role of the vehicle, driver, and highway environment in accident causation must be known and methods to achieve this goal are examined. Despite these limitations, there is progress in understanding the causes of truck accidents.

From various sources of information it is clear that truck noise is a definite public nuisance. Early noise control efforts were very productive in that many heavy duty trucks did not have mufflers, and the addition of this device made clear improvements. Further improvement requires treatment of many sources significant to the overall level. It is felt that today's “tight but attainable” 88 dBA for heavy trucks can reduce to 86 dBA by 1975 and 8k dBA by 1978 with a lot of hard work. There is promise for meaningful noise regulation in the “real world” as indicated by “calibratability” of non-standard sites.

Two high performance industrial machines, the 3400 and 3500 International industrial loader-backhoe, featuring a balanced system of loader integral frame tractor and backhoe design have been introduced to the market. These combinations with matched hydraulic systems optimize operator comfort with machine durability and productivity.

The impact of farm and industrial tractors on the total national emissions picture is difficult to assess because the great diversity of uses for these machines results in a wide variation in duty cycles and degrees of utilization. Also, there is a general lack of detailed information on population and population distribution. This paper compares possible farm tractor duty cycle models and concludes that the widely used 13-mode federal heavy-duty diesel engine emissions test cycle can be used to estimate wheel tractor emissions. Estimates then are given for the amount of pollution released by wheeled farm and industrial tractors in 1972, based on the 13-mode cycle and population estimates derived from U.S. Dept. of Commerce, U.S. Dept. of Agriculture, and Farm and Industrial Equipment Institute data. Calculations show wheeled tractor emissions contribute 3.2% or less of the national total, depending upon the pollutant species.

DURING the period between the two World Wars the track-type vehicle was stimulated into a position of prime importance both in military and civilian applications. This paper reviews the vast strides made in the design of tracks and suspensions, which in turn have led to higher road speed and more efficient utilization of power. However, with the increase of speed, the importance of controllability and power transmission becomes more evident, necessitating careful consideration of the problems of steering mechanism design. The author describes an ideal system which, when and if designed would undoubtedly be universally adopted. But only those who have attempted to come to grips with the problem in a practical manner realize that the final solution will not be a simple one. The present result is that there are almost as many steering systems as there are different types of vehicles. The many reasons leading to such wide-range developments are covered in this paper.

The Vehicle Maintenance Reporting Standards of the American Trucking Associations can be used by manufacturers to improve heavy-duty vehicles. After verifying the accuracy and significance of the data the manufacturing, engineering, technical service and marketing departments can all use the information to improve vehicles and provide better service to the user.

Certain roll over protective structures, ROPS, require resistance to the propagation of brittle fractures at low temperatures. It is demonstrated that the Charpy test is not suitable for characterizing crack propagation resistance. A drop weight test of thin wall tubular specimens was developed which uses a brittle crack starter weld. This test provides an indication of the temperature transition from low to high crack propagation resistance. Because of toughened heat affected zones which can occur in cold formed steel this test is reliable only for hot formed tubes. The temperature transition to high propagation resistance can be determined with precracked Charpy and Dynamic Tear Energy, DT, specimens applicable to cold or hot formed steel. A weld joint simulation specimen was developed to determine energy absorption capacity and low temperature fracture behavior of ROPS joint designs and material.

IN the first part of this paper, Mr. Halgren discusses modified 4-square testing of gears in relation to service performance, field tests, and other accelerated laboratory test methods. It contains a short description and photographs of nine different designs of modified 4-square gear testing machines now in use. Description of machines includes comments on mounting rigidity, mass-elastic system, load application, measurement and control, shut-off devices, and lubrication. Mr. Wulpi discusses single-tooth fatigue testing which is used to measure the bending strength of gear teeth. One tooth at a time is tested in the manner of a cantilever beam. By successive testing, many teeth of the same gear may be tested, and endurance limits obtained if desired. Results of these tests show that it is possible to determine clearly the effect of various metallurgical factors, such as material, heat-treatment, or surface-finishing treatment upon the bending-fatigue strength of gear teeth.

A method of developing a mathematical model of power-plants to simulate engine-governor, or servo systems on a d-c analog or digital differential analyzer is presented. Based on experimental data, the steady-state output of a powerplant is defined as a function of two variables. The dynamics is defined, and the steady-state performance is corrected for response and inertia effects. The resulting mathematical model is discussed with respect to computer applications, instrumentation, and techniques for compiling empirical data needed. Another application is monitoring performance of farm tractors, industrial equipment, and/or automotive systems under field operating conditions. The mathematical model is simulated by an analogous circuit of components that may be inconspicuously mounted on the powerplant in question.

THIS paper outlines the advantages and disadvantages of present-day hydraulic systems. Included in the discussion are: the blocked return line system for single-acting cylinders, the blocked pump inlet, and the basic open-center-valve system. More advanced designs mentioned are: open-center-valve systems with cylinders in series and with parallel cylinders, close-centered valve systems with pressure regulator, and the central hydraulic and accumulator systems. The author points out that the advantages and disadvantages of each system depend to a great extent upon the design in which it is used.

Field performance of tractors with various transmission designs can be determined and compared under identical test conditions. A relatively simple mathematical model of the tractor and implement system provides information like productivity in acres per hour and fuel consumption in gallons per hour. The program provides information for management decision without the costly, time-consuming activity of designing, building, and testing each prototype.

The Fourier Series is used in the development of a continuous function to express cam lifts and accelerations. The mathematics is extended to generate an acceleration response curve which includes the effect of valve linkage flexibility. When a standardized acceleration diagram is established, the variables can be summarized in dimensionless design parameters. Design charts for a parabolic-shaped acceleration curve, suitable for automotive applications, are included. The variables listed as dimensionless parameters include lift, half angle of event, ramp velocity, flow factor, maximum positive acceleration, maximum negative acceleration, acceleration positive pulse width, minimum tappet diameter, base circle diameter, and minimum radius of curvature. Methods of profile synthesis for unsymmetrical half angles of event and matching of profiles to flexible linkages are explained. A dimensionless design chart for valve springs is also included.

The addition of the radiotracer method of wear measurement to the tools available to the development engineer is a great aid, but not a pancea. Its use in conjunction with the conventional approaches can expedite development testing. If the test techniques are properly selected and combined, the ultimate answer can be partially predicted, alternatives screened, and backup engine tests made in a smooth flowing test sequence. Data from two unrelated product development programs are given as illustration. Indications are that piston ring wear predictability can be measurably improved.

Discussed are two high-speed, 4-cycle, turbocharged, compact, lightweight engines recently introduced by International Harvester. These new diesels were designed to meet the requirements of a wide variety of applications ranging from mobile to fixed installations. An analysis is made of the design features and experimental test results of the DVT-573 and DT-429 engines.