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The classical methods of deflection analysis are finding more application to complex automotive chassis frame structures. Much too time consuming for manual application, they are now coming into more widespread use with the aid of high-speed computers. This paper describes a computerized deflection analysis for complete truck frames under the cases of torsion and flexure. The rapid, accurate analysis permits investigation of more design problems resulting in the eventual production of more efficient frame structures.

Since the truck frame is a structural mechanism, the amount, location, and means of obtaining rigidity becomes a most important engineering problem. This problem constitutes the scope of the paper. The types of cross-members and their attachments to the side rails are covered, and methods of improving frame rigidity and test results of developmental activities are presented. The paper concludes with a review of necessary future investigation of the frame mechanism in order to provide specific answers to the question of “how much” ridigity.

Power requirements for driving hydraulic pumps on utility vehicles are increasing while overall cost and weight restrictions are becoming more acute. Improvement in capacities of SAE side mount power take-offs with provisions for direct mounting of pumps would be very desireable in future trucks required by the utility industry.

The transportation of fluids by tank truck has grown to rather large proportions. This is probably largely due to the flexibility of the truck in general, which in turn, is enhanced by the use of PTO driven, truck mounted, pumps that economically and quickly take on and discharge the load. Because of the wide range and varying conditions of materials handled, as well as other varying conditions, many problems exist. This paper deals with some of the most usual problems encountered. It is not intended to be a complete design manual for all PTO driven fluid transfer pump systems, but it should give the system designer a certain basic insight into the aspects which must be considered and properly handled.

Sixty-five percent of the truck mixers delivered in 1963 were equipped with PTO drives. Front end, flywheel, and power tower PTO's are the three types in major use on trucks in the 40,000 gvw class and up. Advantages and disadvantages are discussed. Approximate power requirements are shown. The major problem area is that of space required for the connecting driveline. Major truck obstructions and machinery supplied by mixer manufacturers are illustrated. The need for standardization incorporating space envelopes and the advisability of more cooperation with truck manufacturers are pointed out.

A laboratory for study of earthmoving soil mechanics was developed by the Research Dept. of Caterpillar Tractor Co. Its principal facilities are soil bins for testing scale models of earthmoving equipment, in two sizes. Scale models have many advantages, including lower cost of construction, greater flexibility in the range of parameters that can be investigated, and closer control of test conditions. Models are best suited to basic studies of soil/machine relationships, and to comparative tests of configurations and operating conditions. The paper discusses considerations involved in applying the theory of similitude to earthmoving, the assumptions that were necessary, and some of their implications. The scope is limited to the processes of cutting and loading soil. The importance of qualitative realism in model testing is stressed.

This study combines known facts and engineering principles with new field data to afford prediction of tractor behavior on roadside slopes from a mathematical model. The model was set up for steady-state behavior of a tractor, and it predicted the orientation as well as the stability of the vehicle on somewhat idealized grass slopes. New data were taken on actual roadside slopes, to determine tire creep. Various parameter values were used in a computer analysis to study the effects of tractor geometry, including drive and steer design possibilities. The model was studied for three different tractor and mower units, one of which was equipped with special tires. The results indicate changes for improvements in design as well as horizons for future study.

This paper traces the history of the application of electrical components to off-highway trucks, and then relates it to present-day design. The advantages and disadvantages of the electrical power train are discussed, as is the physical adaptation of the traction motor and generator to off-highway trucks. The author then describes this application from a theoretical viewpoint, presenting illustrative graphical data. Finally, an analysis of vehicle application to haul road profile is presented.

A well-designed and developed hydraulic system for an earthmoving scraper will not only retain the advantages and desirable characteristics of predecessor cable operated machines, but will also add to these all the inherent advantages that have normally been attained in other types of hydraulically operated equipment. Worthy of note among these added advantages are positive bowl and apron down-pressure, good match of ejection speed and ability, ease of operation and preciseness of control, freedom from cable failures, and improved safety of operation at high transport speeds.

A detailed review of the performance under high hydrostatic pressure of the most important deep submergence materials is covered by this paper. Special attention is given to materials with meaningful applications such as titanium, high strength steels and filament wound plastics for structures; buoyancy materials for use external to the pressure capsule and encapsulating materials for external machinery and components. The talk covers in some detail the performance of these materials and touches on several novel approaches such as new techniques for welding and fabrication, methods for encapsulation and new concepts for deep submergence buoyancy systems. The fabrication of high strength and exotic metals under field conditions is discussed in detail and several examples of innovative fabricating techniques are illustrated. The paper includes a look at the decade which follows and a prognosis of what can be expected from materials during this period.

Fleet owners operating on-off highway trucks are continually searching for ways to improve the performance of their equipment. According to them use of the automatic instead of conventional transmissions is one way to obtain this improvement. Performance records of fleet owners operating logging, transit-mix, and refuse trucks equipped with both types of transmissions are examined, compared, and evaluated on the basis of productivity, simplicity of operation, driver training, safety, power train life, and operating cost. Results show that the automatic provides many benefits for the on-off highway type truck and that there is a definite trend toward its use in applications of this kind.

This paper describes four general types of servo-valves and lists some of the advantages and problems of their use in controlling construction machinery. It describes in detail two applications to construction machinery showing the associated electronic sensing and amplifying circuitry with the specific components in the amplifiers listed. This automatic control circuitry is comparatively simple and yet solves a difficult control problem in each case.

A two part digital computer program is being used to evaluate dynamic responses and internal frame forces and moments to assist the design engineer in the design of agricultural equipment. The designs can be optimized for actual field operating environments at a savings of development costs and time.

A concept for combining the separate manual controls of a multiaxis system was explored and demonstrated on a Ford backhoe. The four axes of the backhoe system receive their command signal from a single 4 degree-of-freedom controller. The motion of the backhoe then “mimics” that of the controller, generating a followup signal to close the control loop. This control system provides simultaneous, coordinated control of all four axes in response to natural movements of the human operator.

Improved and increasingly complex farm, construction and industrial machinery demand improved remote control systems. This paper focuses on one element of the mechanical remote control system which is keeping pace with the industry, the push-pull control cable. Recent improvements in material and construction features of push-pull cables make their use in an ever-increasing variety of applications more attractive from the standpoints of cost, ease of installation, durability, and reliability.

This paper describes the use of tooth contact analysis (TCA) to minimize the time required to develop desired tooth contact patterns on spiral bevel gears. The application of TCA to the development of a gear set is demonstrated. Also described is the use of TCA to study the effects of various design parameters on the tooth contact pattern, with particular emphasis on the choice of cutter diameter.

The principal items making up a typical bonded structure (joints, edge closures, doublers and splices, attachments, and core) are examined and their effect on producibility discussed. Certain suggestions toward minimizing the difficulties before they arise in production are made. The importance of prefit checks and department cooperation are also emphasized.

Manufacturing technology development programs for high-temperature-resistant polybenzimidazole and polyimide laminating and adhesives systems and core materials, developed under Air Force sponsorship, have been initiated to fulfill aerospace thermal and structural plastics application requirements. The general objectives are to investigate and evaluate materials and processing variables as they apply to the fabrication of large sandwich structures which incorporate polybenzimidazole prepreg, high-temperature adhesives, and high-temperature honeycomb cores; to develop manufacturing methods for fabricating large plastic sandwich structures which incorporate high-temperature adhesive and honeycomb core, and polybenzimidazole prepreg; and to fabricate three large sandwich structures, using selected materials and processing conditions. Candidate high-temperature-resistant adhesive systems evaluated included: FM-34, PI 5505, Metlbond 840, and Imidite 850.

Structural tests on a 54 in. diameter epoxy-phenolic adhesive bonded titanium honeycomb sandwich tank resulted in failure substantially below design expectations. Company sponsored efforts were undertaken to determine the cause of the discrepancy and to arrive at realistic design parameters for future bonded construction. Of specific interest were the effect of geometric variables, including scaling effects, and elastic properties of adherends and adhesives. The investigations utilized titanium, stainless steel, aluminum, and beryllium adherends and HT-424 and FM-1000 adhesives, the former comparatively brittle, the latter quite tough.

One experimental and twelve commercial diesel crank-case oils of various industry-accepted performance levels were evaluated in highway truck and city coach service. The oil performance parameters evaluated showed that SAE-30, M1L-L-2104B lubricants, as a family of commercial oils, gave better performance than MIL-L-2104A, Supplement 1, Series 3 or multigrade products. Multigrade oils gave very poor performance in both service applications. The results of these two related programs influenced the engine manufacturers’ decision to recommend MIL-L-2104B oils.