Criteria

Text:
Display:

Results

Viewing 164041 to 164070 of 189359
1973-02-01
Technical Paper
730932
George D. Xistris
Machinery maintenance programs based on vibration trend monitoring have been successfully used in several applications. In essence, these programs rely on the interpretation of changing machinery vibration patterns to diagnose developing defects and subsequently define a relative condition index. This information, along with other operating parameters and constraints, is then used to draw up meaningful maintenance schedules. This paper, after a brief review of the vibration monitoring programs in use by the Sea Element of the Canadian Armed Forces, discusses the operational problems that arise in the definition of a vibration health monitoring program for a 750 kW gas turbine generator. It describes in detail the rationale for selecting the location of points where measurements should be made and lists the mechanical components which influence the vibration pattern at each station.
1973-02-01
Technical Paper
730934
Richard D. Ward, Eugene G. Koeller
Computer graphics has become the bridge between the computer and the designer. McDonnell Douglas' CADD system was originally developed for parts layout and solutions to geometry problems, and this restriction was maintained until recently so development could be controlled. Now, with the maturing of the system, several disciplines are converting the computer graphics design package to their special applications. Recent advances in computer graphics software have been adapted to advanced design. The integration of these disciplines has required a number of changes in design techniques in order to evolve and evaluate a conceptual configuration. However, the time savings alone will allow advanced design teams to define and analyze more configurations earlier in the design cycle, resulting in much greater design visibility and with greater accuracy.
1973-02-01
Technical Paper
730938
Alan H. Burkhard
Traditional assembled store vibration testing techniques do not realistically simulate a store's captive flight environment. Extensive flight and laboratory testing has shown that an integrated acoustic and vibration shaker technique can realistically reproduce a store's captive flight vibration environment. This paper describes acoustic tests on six flight instrumented stores, giving details of physical setup, test procedure, and test results. Test procedures and analysis of test data are presented for those stores used to evaluate vibration shaker testing techniques.
1973-02-01
Technical Paper
730936
L. Ascani, G. Hayase
The need for evaluating and optimizing airframes of advanced aircraft configurations with exceptional speed and accuracy has resulted in the development of highly sophisticated computerized techniques. Sensitivity of these programs to advanced materials, construction types, aeroelasticity, structural dynamics, configuration geometry, airloads, missions, and performance has all but obsoleted the statistical approach to the problem solution. The competitive nature of the field has also placed unusually severe demands on calendar time available for such evaluations. This has resulted in the development of integrated analytical computer programs that have the required sensitivity and rapid turnaround time to face the competitive nature of today's environment.
1973-02-01
Technical Paper
730803
R. A. Mengelkamp, R. E. Linnard
Limited route service experience with a commercial 637 CID conversion of a gasoline engine indicated both its potential and the need for its optimization in order to take advantage of the unique characteristics of liquefied petroleum gas fuels. At the request of the Chicago Transit Authority, an engine-dynamometer study, with emphasis on fuel system-ignition relationships, was conducted at the Phillips Petroleum Co.'s Automotive Laboratories. Dynamometer studies led to substantial improvement in fuel economy without depreciation of engine power. Cylinder head redesign by the engine manufacturer permitted lean mixture operation that reduced exhaust emissions to levels calculated to conform to the 1973 federal standards and 1973-1974 California Air Resources Board requirements for heavy-duty engines.
1973-02-01
Technical Paper
730804
Frederick A. Jennings, Walter R. Studhalter
A large number of vehicles are now running on gaseous fuels. Most are using liquefied petroleum gas (LPG), and some are using natural gas (NG). Published studies have listed the advantages and disadvantages of such conversions, but these have had an unexpected degree of understatement and take a very stringent view of the emission advantage, giving the impression that vehicles using gaseous fuels cannot compete with emission control of the clean gasoline-powered vehicles planned for 1975. This conclusion will probably be proved erroneous when all data are available. As compared to clean 1975 gasoline vehicles, gaseous-fueled vehicles will probably be cheaper to run and more reliable. Disadvantages include limited distribution of gaseous fuels, limited fuel-carrying capacity, some regulatory limitations, and a need for more highly developed hardware. Despite these problems, there is a small but important market where conversion will be very profitable for the owner and the community.
1973-02-01
Technical Paper
730800
John C. Straub
The purpose of this paper is to illustrate the value of shot peening in reducing production costs where high volume is concerned. Its potential as a means of reducing part size via increased fatigue strength can result in saving material to the extent of hundreds of dollars per day. The significance of the distribution of residual stresses within the shot-peened part is discussed, and theories are presented in an attempt to explain some of the startling effects of shot peening. The economics of efficient operation of peening equipment are discussed, and suggestions are given to minimize operational costs.
1973-02-01
Technical Paper
730802
J. R. Allsup
The Bureau of Mines studied the characteristics of simulated coal gas as an automotive fuel in a multicylinder engine in a standard and high compression ratio engine configuration. While using simulated coal gas fuel, increasing the engine compression ratio improved the fuel economy and vehicle performance but increased hydrocarbon emissions by 40%. An oxidizing catalyst used with the simulated coal gas fuel resulted in elimination of all but trace amounts of carbon monoxide and reactive hydrocarbons in the exhaust. Spark gap geometry and firing voltage were varied and within the range tested had little effect on vehicle performance and emissions using simulated coal gas fuel.
1973-02-01
Technical Paper
730798
John W. O'Connor
The use of the Oklahoma State University Pump Contaminant Sensitivity Test, OSU-F2 Multi-pass Filter Performance Test, and knowledge of hydraulic fluid contamination levels in field tests have proved to be highly effective tools in the development of a reliable hydraulic system for a modern farm tractor. Goals for an improved filter system were: To provide as much filter capacity as economically possible; to increase the filter flow rate; to isolate the pumps from the sources of contaminants. These modifications corrected the problems: Brake friction surfaces which generated less contaminant; a pump with greater contaminant tolerance; an improved filtration system.
1973-02-01
Technical Paper
730799
H. S. Blair, J. A. Hildebrandt
The conversion from submerged arc welding to electron beam welding (EBW) of transmission components at Clark Equipment Co. is described. The latter system permits the consistent holding of close tolerances and the obtaining of controllable and repeatable metallurgical structures. In addition, control of the weld and distortions is increased, and weld joints are made feasible in otherwise inaccessible locations. A brief history is presented which touches on the selection of transmission products for EBW, choice of EBW equipment, preliminary evaluation, and acceptance of the process by personnel. Then, the application of EBW to production parts is discussed.
1973-02-01
Technical Paper
730796
E. C. Fitch, R. K. Tessmann
The multipass filtration performance test which has recently gained industry-wide support offers many fundamental ways of describing the performance characteristics of fluid power filter elements. Some of these descriptions are uniquely qualified to provide the system designer with a practical technique for appraising the capability of filter elements. Important appraisal parameters of a filter element which must be considered by a designer are particle separation capability, contaminant capacity, and pressure loss. In order to specify a filter element properly for a given application, the requirements for the appraisal parameters must reflect the needs of the system components. A practical and fundamental description for the performance of fluid power filters will incorporate appraisal parameters which can be related to the demands of such system components.
1973-02-01
Technical Paper
730797
P. J. Wilson
In any hydraulic system, we can, without reservation, say that the cleaner the fluid the better. But, since absolute cleanliness is usually unobtainable, it becomes important that we can readily measure and define the degree of cleanliness in a practical way. Two parameters seem important: number of particles and particle size. In examining hydraulic components as to type and usage, two areas of particle size are of special significance, 5 and 15 micrometres (μm). By counting all particles in a fluid sample above 5 μm and also counting all particles above 15 μm, two indexes are given from which a contaminant code* is derived. The thesis of this paper is that this code is useful in predicting the performance of specific components with the fluid.
1973-02-01
Technical Paper
730793
J. C. Guignard
The recent work of the International Organization for Standardization (ISO), Technical Committee 108, Mechanical Vibration and Shock, Subcommittee 4 (ISO/TC 108/SC4, Mechanical Vibration and Shock Acceptable to Man) has established guidelines (Draft International Standard ISO/DIS 2631) for the evaluation of human response to whole-body vibration in the range of 1-80 Hz. These guidelines, which are subject to revision and to extension of the frequency range in the light of new and better data, provide a current consensus as to the limits of acceptable human exposure to whole-body vibration in vehicles, buildings, and workplaces, according to selected criteria: comfort, working efficiency, and protection from injury. The limits are expressed in terms of acceleration as a function of direction and frequency of vibration and daily duration of exposure.
1973-02-01
Technical Paper
730795
John Matthews
Methods of assessing the ride comfort afforded to tractor drivers by their vehicles and the ride improvement provided by seat suspension are reviewed in relation to information available on the human tolerance to whole-body vibration. Experience with different methods of measurement is reported and a proposal made for the establishment of an internationally agreed method of ride comfort rating based on standardized undulating surfaces over which vibration of the driver's seat is analyzed, using frequency weighting to represent the differing sensitivity of the body to different vibration frequencies.
1973-02-01
Technical Paper
730791
Clayton LaPointe
The recent history of automotive fuel economy in the United States is reviewed. As of the 1973 model year, the individual typical car on Ford's city-suburban route has experienced a 22% decline in fuel economy compared with that of 1967. In the aggregate, however, the decline has not been as great because an increasing proportion of small cars has entered the vehicle population. The factors which have contributed to the fuel economy decline of the typical car are average weight and engine displacement increases and measures taken to reduce exhaust emissions. As of the 1973 model year, emission controls have accounted for 60% of the total 22% decline based on Ford's city-suburban route.
1973-02-01
Technical Paper
730792
E. Gunnar Ahlstrom
A farm tractor protection cab made of thin steel sheet pressings is described. The cab is designed and produced using entirely automotive-type procedures. Curved glasses and a dampening suspension of the glasses are found to be an important means of achieving a low noise level in the cab. Using the pressing technique when producing a steel cab makes it possible to give the various cab details rigidity with a minimum of material. When welded together, these details form a very stiff cab body, which gives the necessary mechanical strength. The curved surfaces, the radii, and the round forms, which from a tooling point of view are natural for pressed steel parts, also have a vibration-dampening effect on the entire cab construction, thus making it easier to design a quiet tractor cab. Mounted on a farm tractor of conventional design, the cab meets the noise rating number ISO N85.
1973-02-01
Technical Paper
730788
Horace F. Howell
This paper outlines the structure and interrelationships of the numerous European standards making organizations, with particular reference to agricultural machinery. Because many of the standards being developed by these organizations are becoming part of legislation in the various Common Market countries, their work is of great interest to the machinery manufacturers. Covered are the highway code-constructional requirements, safety constructional requirements, test codes, and engineering standards. The current status of requirements for lighting, tractor cabs (including structural tests, noise, and emissions), maximum speed limits, brakes, hitches, and safety in the various contries are discussed.
1973-02-01
Technical Paper
730790
Thomas C. Austin, Karl H. Hellman
This paper discusses some trends and influencing factors in passenger car fuel economy. Fuel economy and fuel consumption were calculated by a carbon balance method from HC, CO, and CO2 emissions measured by the 1972 Federal Test Procedure. The information presented was derived from nearly 4000 tests of passenger cars ranging from 1957 production models to 1975 prototypes. Data are presented for various model year and vehicle weight categories. Trends in fuel economy are discussed on an overall sales-weighted basis and for each individual weight class. Some of the factors that influence fuel economy are quantified through the use of a regression analysis. Particular emphasis is placed on the differences in fuel economy between those vehicles that were subject to federal emission regulations and those vehicles that were not. Three ways to characterize vehicle specific fuel consumption are presented and discussed.
1973-02-01
Technical Paper
730786
James J. Bauer
Compared with conventional power trains, available axial piston hydraulic pumps and motors provide the designer of work vehicles in the 15-80 hp sizes an opportunity to improve the productivity, reliability, and serviceability of his machine. This paper provides the designer with information frequently overlooked in the initial application of these units.
1973-02-01
Technical Paper
730787
R. V. Burton
The increasing use of hydrostatic drives in industry has motivated development of fluidic control devices, using hydraulic oil, for application to hydrostatic transmission pump displacement control. A closed-loop positioning servo using proportional hydrofluidic amplifiers and flowing hydraulic fluid to replace the numerous mechanical parts common to conventional servos has been developed. This hydrofluidic servo has been built in both a packaged servoactuator form and a modular form for integration with existing hydrostatic transmission pumps. Operating principles and performance of experimental units are discussed. Operation was evaluated over a 160-500 psig (11-34.5 bar) supply pressure range using fluid viscosities ranging from 220-5 cSt. It was concluded that hydrofluidic servos are practical and that their application in industry will be contingent upon the availability of off-the-shelf components.
1973-02-01
Technical Paper
730830
M. Van Loan, Larry Resnick
As control strategies for both mobile and stationary sources have been implemented and have become effective, they have caused a significant reduction in California's air pollution problem. New strategies are focusing on heretofore uncontrolled emissions sources. The California Air Resources Board has supported a study to assess the current and future significance of currently uncontrolled mobile and semimobile sources of emissions powered by internal combustion engines. The two primary goals of the study were to develop an emissions inventory for those emissions sources in California not presently controlled by existing legislation and regulations and to make an accurate determination of the contribution of these sources to California's total air pollution problem. This paper focuses upon the results of the ARB-sponsored study as it relates to farm and off-road heavy-duty equipment.
1973-02-01
Technical Paper
730829
G. C. Hardwick, C. R. Hudson
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.
1973-02-01
Technical Paper
730825
M. B. Pearce
Traditional mechanical methods of preventing fasteners from loosening are now being reevaluated. Consumerism has put a priority on safety and reliability which has triggered a move toward a greater use of locking fasteners. The American National Standards Institute Subcommittee B18:20 on the performance of locking fasteners is currently drafting performance specifications on chemical-locking and free-spinning fasteners. The SAE Subcommittee on Vibration Testing of Fasteners has also begun to screen fastener testing equipment. The author of this paper, actively involved with both groups, offers a preview of locking fastener identification, benefits, and problems; also, fastener performance employing the latest transverse shock and vibration equipment, which shows that lock washers do not really lock.
1973-02-01
Technical Paper
730824
J. Huot de Longchamp
A short survey of the literature about human tolerance to vibrations and about seat transmissibility is presented. A brief summary of European regulations concerning seat characteristics will include not only vibration absorption requirements but also recommended dimensions and necessary adjustments. Safety rules as issued in some countries, in particular for tractor seats, are also discussed. The practical problem of making a seat in accordance with all these factors at a reasonable cost with durability and easy adaptation to the unskilled user will be discussed as a compromise. Conventional systems and new trends are briefly indicated.
1973-02-01
Technical Paper
730823
Larry F. Stikeleather
Since vehicle seats interact dynamically with the human body, testing the response characteristics of such seats for proper application is important. Likewise, the methods and techniques used for such evaluations are equally important if meaningful results are to be obtained. This paper discusses two quantitative test procedures applicable primarily to judging the relative performance of several seats with regard to dynamic characteristics. In particular, the equipment and procedures necessary to plot seat transmissibility are discussed and specific example data are shown for two suspension seats and a static cushion seat. Also, equipment and procedures for assessing the relative dynamic response index (DRI) are discussed and example results for a suspension seat and a cushion seat are included.
1973-02-01
Technical Paper
730822
W. R. Bryant
This paper presents a description of the new Allis-Chalmers model 7030 and 7050 high-horsepower row crop agricultural tractors. The development of the new power train with 20 forward speeds, hydraulic system with 45 gpm output, engine, chassis, and cab has provided the function, safety, performance, convenience, and serviceability required in modern farm operations. Several new options have been developed, and other improvements have been made, especially at the operator's station.
1973-02-01
Technical Paper
730820
Thomas D. Whelpley
A unique laboratory system for evaluation of agricultural tractor engines and power trains has been developed which closely simulates field loading, operates on a continuous 24 h basis, and is fully automated to reduce manpower expense. The programming hardware in conjunction with a dynamometer system provides a continuous and efficient method of indoor evaluation which correlates well with results from field test units. A master load histogram produced from collected field data was used to derive an engine loading cycle. A data logging system monitors the test stands during unattended times. Certain shortcomings-lack of reaction to environmental conditions, geographical differences, an operator's “feel” of a vehicle-will not totally eliminate field testing.
1973-02-01
Technical Paper
730821
Luigi Ponzio
In the development and finalization stages of a new tractor, it is extremely important to take market requirements into account. These determine the main characteristics of the model: engine power, tractor dimensions, weight, and power train type. In describing the development of the Fiat Model 1300 tractor, the author first explores the requirements of European farmers as opposed to American farmers. Then, calculations used in the determination of the power and weight of the tractor are presented. Next, the advantages of 4-wheel and 2-wheel drive are compared. The choice of engine and transmission for the Model 1300 tractor is explained, and rear tire specifications discussed. Other items such as rockshaft, three-point linkage, and towing devices are also considered, and a detailed description is given of the driver's compartment.
1973-02-01
Technical Paper
730819
Robert E. Haight
A punched tape program is being used to control power shift transmission test stands operating as single or multiple units. Any desired shift sequence (sequence or skip shifting) is availabel with no concern for rate of shift lever movement, accuracy of detent postions, etc. Transmission shifting is accomplished by using electric solenoid valves to control the shift valves. Test unit design and construction, the test controller, test cycle design, test results, laboratory-field correlation, engine, costs, and test stand deficiences are covered. This system provides test flexibility, rapid data acquisition, engine life data, and minimum equipment investment.
1973-02-01
Technical Paper
730818
Vernon G. Converse
Transmissions for off-road vehicles are tested functionally at the end of the production line under conditions which as nearly as possible simulate those of actual use. Pallets are used to obtain high utilization of the testing equipment. A check is made of such factors as regulator pressure, lube pressure, drag losses, gear noise, and torque under specific conditions. A description of the testing cycle, methods employed, and readings obtained is included.

Filter

  • Range:
    to:
  • Year: