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The agri-businessman is increasingly being faced with the need for more efficiency in his operations and awareness of the importance of an improved working environment for himself and his workers. John Deere has introduced a new line of row crop tractors intended to help meet those requirements. Numerous details of design contribute to the major concepts of increased power in compact, maneuverable chassis, new power train options, improved operator environment, including ease of operation and good serviceability.

Evolutionary design may be defined as up-grading an existing design to improve marketability, while still retaining fixed parameters of cost, weight, size, and related attributes. When the project involves an already well-designed and acceptable product, then further evolution of the design requires some novel approaches. This paper discusses the evolutionary design of compact skid-steer loaders. Powerplant, loader efficiency, service and parking brakes, and service accessibility are covered.

The stability of a hydromechanical steering system on a rough-terrain vehicle was investigated in an effort to eliminate limit cycle oscillations and an insensitivity to small perturbations of the steering wheel. Because of constraints imposed upon the problem, the basic system configuration was considered to be fixed. A linear analysis of the system was adequate to indicate possible components for modification, and nonlinear analyses of the indicated components proved to be accurate design tools. The problem was solved by redesigning two valves and a feedback linkage.

The Hyster C610A represents a unique concept in self-propelled vibratory compactors. A single trunnion mounted high flotation drive-steer tire was the basis for achieving major design objectives of improved traction and maneuverability. Hydrostatics has been employed throughout for transmission of engine power. Required for the new design concept was a rotary hydraulic union with capacity for 50 gpm and 4700 psi. Problems related to the hydrostatic transmission, drive tire, and controls were solved, resulting in a durable and efficient compaction tool.

Many of the requirements for rotary power on farm, construction, and industrial machinery can be best satisfied by the use of hydraulic motors. Remote mounting capability, unlimited rotation, reversibility, good variable speed control, and small size and weight are some of the general advantages made possible by the use of hydraulic motors. More specifically, low-speed high-torque hydraulic motors offer even more advantages to the product designer. In many cases these motors eliminate the need for gearboxes and reduce the number of other mechanical components, thereby providing increased design flexibility in the end product.

Speed and pressure response of a hydraulic motor to changes in flow (stroking a directional valve) is predicted for typical mobile hydraulic circuits. A simplified approach was used to derive the equations for a system consisting of a pump, directional valve, and a motor with an inertia load. The speed and pressure response to increases in flow was studied by solving the equations on an analog computer. Expressions for the natural frequency, ωn, and the damping ratio, ζ, were written in terms of motor displacement, load inertia, system compliance, and system leakage coefficient. The response to increases in flow is presented in terms of the damping ratio. The response to decreases in flow is discussed for directional valves with both open and closed cylinder ports. The effects of the simplifying assumptions of the valve stroking rate and of the valve cylinder port configuration are discussed.

The rotary actuator, a device which converts hydraulic fluid under pressure into rotary mechanical motion, is very useful in applications that require limited turning motion. Several applications are described in this paper, and illustrations are presented. Descriptions of the two basic types of rotary actuators, the vane and the piston, are offered. The latter type is further divided into the helical-spline, piston-rack, and piston-chain.

A rubber track has been developed for use on all-terrain vehicles (ATV). This track offers the advantages of low ground pressure, excellent climbing ability, long flex life, and puncture resistance. This track uses a series of internal lugs for propulsion and can be manufactured with any desirable tread pattern. This paper will present the advantages and some of the technical aspects of this track.

Flotation tires on all-terrain vehicles (ATV) are an essential component for good, overall off-the-road mobility. Water displacement by the large volume tires provide additional buoyancy for amphibious vehicles. The large contact area of the deflected tire provides low ground pressure for flotation on soft ground. ATV tires are a special breed of tires with design features for better mobility such as carcass flexibility, wide tire section, and special tread design.

Within the past 15 years, the solid wastes management field has experienced an extensive technological advancement. This advancement has brought the field into parity with other segments of the materials handling and construction industries. During the coming decade the solid wastes industry will experience a continual technological refinement and maturity in areas of waste collection, transfer systems, resource recovery, and disposal. The rapidly expanding demands for service combined with the constraints for economical systems for waste management will accelerate the automation of selected processes formerly based upon labor-intensive procedures. This paper highlights the current state-of-the-art for waste management and identifies areas where technological improvements could lead to significant manpower and productivity achievements in the field.

This paper describes the design, steady-state and typical dynamic performance characteristics of a line of pressure and flow compensated pumps. Particularly, the influence of the application parameters on the dynamic characteristics is discussed and illustrated. Some installation considerations are also given and a few successful applications (to farm tractors, dozers, trucks, and jumbojets) are demonstrated.

A compensated hydraulic system is a system in which the pump automatically compensates or reacts, usually by a change in displacement, to some change in its operating condition or to some external signal. An almost endless variety of operating characteristics to provide many conveniences is possible. Pressure- and flow-compensated systems are familiar but still have new possibilities. In addition, torque compensation, speed compensation, and various hybrid systems are now feasible. The features of several existing and proposed systems are examined in this paper.

A survey of spray literature has been carried out in order to find all those works containing a theoretical or experimental correlation of spray penetration variables. Twelve such works were found. Three hypothetical sets of conditions based on actual data from the Sulzer LVA24 diesel engine are used to test the correlations. The results obtained from applying the three sets of conditions are given as penetration-time curves. The effects of injection pressure, air density, and nozzle orifice diameter on the penetration predicted by each correlation, are also shown in penetration-time curves. An analysis of the results leads to several conclusions from which recommendations are made as to whether each correlation is suitable for use under conditions prevailing in modern diesel engines. Future trends in medium speed diesel engine conditions show that all but two of the twelve correlations will not give satisfactory predictions of penetration under these conditions.

A new fuel filter by Stanadyne is described. Its development, including shape and paper selection, is covered. The Master Filter makes use of unusual packaging concepts and techniques to overcome the ever-increasing problem of short filter life as diesel engine horsepower increases. Fuel filter paper evaluation, selection, and test results are described. Comparisons of, and arguments for, more realistic filter test methods are provided. Supplementing the fuel filter is a new type of water separator using similar packaging concepts. This simple design provides very good capability for water removal at high flow rates. A water separator test method is outlined. Both products offer contaminant visibility to encourage system maintenance.

Until quite recently, it appeared that there was an effective lower limit on bore size in open-chamber diesel engines. This paper presents a technique for improving combustion in the small open-chamber diesel engine. Recent work at MIT on a 2-1/2 in bore, short-stroke diesel engine has demonstrated that good efficiency can be obtained through a combination of a large-hole nozzle and the use of air swirl to prevent overpenetration. There is some indication that good efficiency can be obtained over a wider operating range than standard diesel practice. A method of design analysis for this type of engine is presented, along with techniques for estimating the swirl and nozzle design parameters.

The 528 wheel skidder represents a second-generation machine designed and tested to satisfy the requirements of the large wood areas of the world. Numerous unique features were incorporated in the design to meet the special needs of the logging customer; these are described, along with the development program that yielded the present vehicle.

The forestry products manufacturers are being forced by economic pressures into producing wood handling equipment of larger capacity and more efficient operation. Consequently, four-wheel drive articulated skidders of larger sizes and increased horsepower are being designed and built. John Deere's JD740 Skidder is one of these units. This paper presents the design features of the JD740 and discusses aspects of these features important in their selection to meet the original design goals.

Twin-powered self-loading scrapers are relatively new in the construction equipment field. The high horsepower to weight ratios coupled with all-wheel drive give two axle scrapers excellent performance in the cut, on the haul road, and in the fill area. Self-loading is accomplished with heavy-duty elevator systems. Loading time and distance is less than that experienced with single engine elevating scrapers. This type of equipment, in the 20 and 30 yd3 class, is geared to handle a wide variety of construction and mining production jobs and has long since graduated from the “cleanup tool” and “potato dirt” type equipment.

This paper discusses fully-developed digital control systems used in vibration testing. The fundamentals of control are presented, along with a discussion of the final systems evolved. Of particular importance is the need to fully exploit the new levels of automation and safety available when computers are used. Performance is demonstrated using the results of operational tests.

The aircraft engines represent from 40-60% of the total direct maintenance cost of a commercial airliner. The engines, along with tires and brakes, represent the “consumable” components on the airplane. The engine's requirement for high reliability, coupled with its approximately 50% share of the aircraft maintenance cost, has required development of numerous reliability, performance monitoring, and inspection tools and programs to assure its good health at minimum cost. Engine performance monitoring is one of the programs that has been developed. The scope of in-flight engine performance monitoring ranges from a slide rule in the cockpit to a completely instrumented engine monitored by an onboard computer. This paper will review United Air Lines' engine monitoring program, which is a compromise between the slide rule and the onboard computer. The flight log monitoring program is reviewed and UAL's decisions not to install AIDS are explained.