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Viewing 164041 to 164070 of 188468
1972-02-01
Technical Paper
720665
R. Dale Beland
To date new transportation systems have failed to avoid the impact of noise on the surrounding community, due to lack of adequate planning in terms of depth of research and analysis, lack of attention to the whole problem of noise pollution, and the lack of coordinated planning of communities and the transport system that serve them. This paper discusses several ways to achieve greater coordination between community planning and transportation planning in order to reduce noise. A systems approach should include the steps of identification of objectives, identification of programs, prediction of effectiveness, and evaluation of alternatives. Several means of doing this are discussed.
1972-02-01
Technical Paper
720669
J. C. Selby
The purpose of this report is to develop analytical models that may be used to determine the size and number of trucks required to provide a given service level at the lowest possible cost. Two models are presented, they are: 1. The Simulation-Linear Program Truck Selection Model: This model employs simulation to determine the number of miles driven and linear programming to minimize the “total cost objective function.” 2. The Truck Salesman's Truck Selection Model: This model is less accurate than the “Simulation-L.P.” model but is also less laborious and easier to use. It applies “trial and error” solutions to the L.P. objective function and uses other equations developed for the Simulation-L.P. model to make these solutions as accurate as possible. The two models have been used on a number of case studies and similar results have been obtained. Thus, it is hypothesized that because the results are similar the models must be correct.
1972-02-01
Technical Paper
720676
H. A. Helstrom
This paper presents a graphic picture of the problems facing the aeronautics industry in the state of Texas. Following the national pattern of aerospace distribution of employment, the slowdown of contracts in this industry to firms employing approximately 80,000 people, has created a not too pleasant picture. While the situation appears to be stabilizing, diversification to other, allied, fields, such as ground transportation, with its air cushion vehicle systems, LIM-powered systems, etc., is called for. A plea has been made for engineers to apply their talents to other than aerospace production, and to develop new products and markets.
1972-02-01
Technical Paper
720678
Kazuhiko Aoki
In order to determine the operational characteristics of human pedal force, a driving simulator consisting of a driver's seat, pedals, analog computer, double gun synchroscope, etc., was developed. The driver was asked to guide the spot representing the controlled variable using the spot as a target. A simple transfer function to match the test results was derived and the effect of parameters on the constants in this function was analyzed. This experiment established that a pedal force of 200 daN seemed best for control.
1972-02-01
Technical Paper
720681
Louis J. Lawson
The need for new mass transit vehicle alternatives has been spurred by the growing concern in our cities over photochemical smog, noise, smoke, odor, and transit system operating deficits, which are to a large degree the products of present rolling equipment. A project planned in conjunction with the San Francisco Municipal Railway is intended to demonstrate a practical kinetic energy (flywheel) propulsion system providing optimized electric transit with route flexibility and increased quality of service. The dual-mode trolley coaches used for the demonstration will be capable of providing scaled operational data that can be extrapolated to new classes of ecologically and socially acceptable vehicles.
1972-02-01
Technical Paper
720805
Arthur J. Glassman, Warner L. Stewart, Stanley M. Nosek
The requirements imposed on the airbreathing engines by the shuttle mission and some results from engine design studies are discussed. In particular, some of the engine system weight study results are presented, potential problem areas and required engine modifications are identified, and testing requirements for a development and qualification program are discussed. The engines of interest for the shuttle are engines that are currently being developed for other applications. The potential problems, engine modifications, and testing requirements result primarily from the new environments associated with launch, space residence, and reentry.
1972-02-01
Technical Paper
720803
J. L. Rau
Simplified power steering control of large off-highway vehicles still remains a formidable problem for steering system designers. Several hydraulic power steering mechanisms presently prevail with varying envelope and performance features compromised for off-highway application. This paper describes the first low-cost positive displacement-type hydrostatic steering unit especially designed for the large off-highway vehicle industry. The basic features of the HGB hydrostatic steering system are discussed relative to set goals in each major design area. It is shown that the HGB Hydraguide meets the general requirements for a simplified high-flow hydrostatic steering unit adaptive to the off-road construction and earthmoving machine.
1972-02-01
Technical Paper
720802
John B. Waggoner
Smooth, effortless steering systems for large, articulated vehicles enhance their production performance. This paper deals with the complete primary steering system and also brings into focus an approach to the current industry need for a back-up, or secondary steering system. The individual components of both primary and secondary steering systems are discussed in detail from a design and functional standpoint. The overall system performance is then discussed to identify clearly the various component functions and relationships.
1972-02-01
Technical Paper
720801
Gerald W. Bernhoft
The use of a low-pressure, low-volume pneumatic pilot system and amplifiers provides superior control of the dipper and dipper arm of a hydraulic hoe when used in conjunction with pressure-compensated four-way hydraulic valves. The use of a split-control regulator and pilot valve provides automatic proportioning of flow for simultaneous operation of a tilt with extend or dig functions. Since the position of the control lever represents a given flow, regardless of the hydraulic load, an operator can positively proportion the speed of the dipper and dipper arm cylinders.
1972-02-01
Technical Paper
720798
Robert C. Lehman
This report discusses two topics: the history and the development of the present off-highway minimum performance criteria for braking systems and the current activities of Subcommittee X - Vehicle Brakes - of the SAE Construction and Industrial Machinery Technical Committee. The Subcommittee has currently been developing a revision to SAE J237, Minimum Performance Criteria for Braking Systems for Off-Highway, Rubber Tired Front End Loaders and Dozers. The proposed revised report is included in an appendix. When approved, similar revisions will be made to SAE J166, J236, and J319. The revisions cover failure of a component common to both service and emergency stopping systems, holding performance, system recovery, weighing accuracy, and failure of parts. The background reasons for these revisions are described.
1972-02-01
Technical Paper
720794
Orton E. Larson, David F. Lemons
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.
1972-02-01
Technical Paper
720791
Christopher K. Smith, Henry R. Sebesta, James E. Bose
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.
1972-02-01
Technical Paper
720787
F. E. Simpson
The recently announced Model 225 Excavator is Caterpillar Tractor Co.'s initial entry into the hydraulic excavator market. The development program for this machine was designed, from the beginning, to achieve a machine well suited not only to the United States but to overseas markets. Major features of the vehicle, and how these features were affected by unique aspects of the development program, are discussed.
1972-02-01
Technical Paper
720790
Maurice Klee
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.
1972-02-01
Technical Paper
720788
Roy A. Gillette
The design changes made on the 14 ft Case 580B backhoe-loader to upgrade its overall performance level are described in this paper. Increased productivity was obtained by use of a higher horsepower engine, adoption of twin boom cylinders, improvement of bucket digging power, addition of an optional attachment, and provision of two position stabilizers with lock checks on the cylinders. Lift capacity of the loader was also increased. A new operator seat was designed and various modifications made to provide easier operation. Ease of maintenance and repair was also improved. Optional equipment for the backhoe-loader is also described.
1972-02-01
Technical Paper
720785
Bernard Triai, David Jezwinski
High-pressure hydraulic systems (operating at pressures of 3500 psi or greater) are replacing mechanical systems with smaller and more reliable machines. This paper discusses the existing limitations of the technology of high-pressure hydraulics, as well as the advantages of systems working at pressures in the area of 5000 psi. An analysis is made of a hydraulic circuit and its components, including the reservoir, pump, valves, motor, cylinders, hoses, and fluid.
1972-02-01
Technical Paper
720786
Joseph Fox, Luft A. Alvi
This paper describes a hoist dynamometer capable of reproducing field conditions for the purpose of providing comparative data on friction materials used on band brakes and clutches by the crane and hoist industry. Performance qualities essential to the braking system are recorded for both automatic and manual operation. The dynamometer enables the testing to be performed under controlled conditions which can be both repetitive and reproducible.
1972-02-01
Technical Paper
720784
C. A. Brolin, H. E. Durscher, G. Serentha
A series of tests to ultimate failure was conducted on lattice type crane booms. The results of these tests, correlated to predicted mathematical values, demonstrated that ultimate load capacity can be predicted accurately and that SAE J987 “Crane Structures-Method of Test” results in proper but probably conservative ratings. The proposed SAE Recommended Practice, “Latticed Crane Booms-Analytical Determination of Stresses and Critical Loads,” appears to give reasonable ratings when compared to actual failure loads. This work and results presented suggest that the day may come when such structures can be rated based on ultimate or critical load rather than on critical stress.
1972-02-01
Technical Paper
720778
Leonard Reimer
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.
1972-02-01
Technical Paper
720780
John M. Karhnak
Over the past several years, the Army has become increasingly aware of the disastrous effect of solid particle contamination on the life and efficiency of fluid power system components. Something must be done to give a more reliable, quicker, and more accurate check on the system condition at any given time. In July 1971, the Army Mobility Equipment Command acquired a prototype portable automatic particle counter for use on fluid power systems. This battery-operated counter connects directly to the vehicle or test stand at a fixed, predetermined test point, eliminating the need for sample containers and simplifying the test procedures. Connection, analysis, and disconnection takes less than 5 min. The portable counter has been used on a number of vehicles with verification samples being taken and checked by Oklahoma State University. Results to date have encouraged the Mobility Equipment Command to continue with the field verification program.
1972-02-01
Technical Paper
720779
Kurt R. Lonnemo
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.
1972-02-01
Technical Paper
720774
Rodney H. Anderson, George R. Heidenblut
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.
1972-02-01
Technical Paper
720773
L. E. Miller
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.
1972-02-01
Technical Paper
720776
N. Hay, P. L. Jones
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.
1972-02-01
Technical Paper
720769
W. L. Sumpter
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.
1972-02-01
Technical Paper
720771
George D. Herbst
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.
1972-02-01
Technical Paper
720772
Ronald G. Rumpf
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.
1972-02-01
Technical Paper
720766
M. W. King
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.
1972-02-01
Technical Paper
720765
M. L Pules, D. J. Eves
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.
1972-02-01
Technical Paper
720768
Richard A. Klimaszewski
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.

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