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According to the tractor theory, the operating mass of a tractor is calculated from its traction force required to overcome the resistance of soil-cultivating implements and provisional incidental overloads. Implements' resistance changes are estimated by the coefficient of possible overload -- the ratio of maximum possible resistance to its average value, i. e. the maximum resistance value of the implement is used for calculations One of the regulating agricultural operations in the choice of tractor's operating mass is plowing. Besides, the implement's resistance change with the speed increase of the tractor's aggregate is not taken into account. The operating tractor's mass calculated by this method is by 10…20% different from the optimum operating mass.

In peak periods, producers lose valuable time due to tractor breakdowns because of parts availability and service problems. A survey of 200 producers was conducted across the Province of Saskatchewan to determine problems associated with service and availability of parts. The results show that the dealerships were becoming more responsive to the producers needs. The number of repairs per year and the cost of dealership repairs were high since 14% of respondents were using private mechanics. The number of tractors per producer nearly doubled from the 1960's estimate of two. The hydraulic components were a concern since the cost of repairs was high, and breakdowns were more frequent.

Experiments comparing hollow-core and solid large round bales of high moisture alfalfa hay (20-30 % w.b.) for drying rate on a solar-heated, forced-air dryer showed that hollow-core bales dried more than 50% faster than solid bales of equal dry matter density and moisture content. Results encourage the use of hollow-core bales to develop more compact, simpler, cost-effective designs for solar-heated, forced-air dryers to preserve premium quality hay at reasonable cost in humid climates. Three new machine items will be required, including an attachment for balers to form hollow-core round bales.

The latest evolution of an experimental prototype of a vibrating digger blade for harvesting sweet potatoes is described. In 1994, after several series of formal tests with a research machine, a mode of vibration which appeared optimal was determined. A prototype vibrating digger blade which would retro-fit a commercial sweet potato digger was designed. This paper describes the design and testing of the blade. The blade was fitted on one side of a two-row commercial digger. Though testing was limited and conditions were not ideal, the vibrating blade showed much better soil flow than the fixed blade. This indicated that development of the system should be continued.1

To assist crane operations planners and others to assess the risk of overturning in crane operations, consideration is given to the action of a short duration dynamic force on a generalized free standing crane loaded with a system of static overturning and stabilizing forces. An equation has been developed to reflect an equivalent dynamic moment for comparison with the static moments acting on a crane. A rule is found that combines into one overturning moment the effects resulting from two or more simultaneous impulses induced by several crane mechanisms. It is shown how crane or installation parameters can be altered to reduce and control overturning risk in crane operations, and how accident investigators can achieve a realistic appreciation of dynamic episodes.

As more and more functions of agricultural tractors are automated to make farming operations faster and easier, designing efficient driver controls becomes more and more crucial. The French Institute of Agricultural and Environmental Engineering Research (CEMAGREF) and The Ecole Nationale Supérieure d'Arts et Métiers (ENSAM) developed a method to assess drivers' reaction to a new driver controls system including both a psychological and quantitative approach. A physiological approach was also considered, but could not be instrumented in the tractor-cab's environment. A group of eight farmers were used to test the method by evaluating a new automated control system on a tractor. This experiment pointed out that a good indicator of the driver's trust and understanding of the control system was given by the ability to imagine new ways or new conditions in which it could be used.

The European and German road legislation differs widely from the US-American road legislation. As there is no specific European type approval for farm machinery other than tractors, this paper will focus on the German road legislation, which, being among the toughest in Europe, will be accepted in most European states. The paper will cover the relevant design issues, known by us to cause problems when US-American farm machinery is to be exported into Germany. Among them are dimensions and weights, steering and brakes, noise, lights and emissions.

Current design methods have focused on the integration of diverse engineering and management functions to assist in the management of the product development process. At present, existing product development tools do not allow engineering and management to quantitatively assess the cost-performance trade-offs that exist in product designs. The lack of quantitative measures of product cost-performance relationships prevents engineers from determining the cost of product features and performance, and effectively bars non-technical management from product configuration decisions. An integrated design method would combine engineering and cost relationships within a single analytical framework through the extension of probabilistic performance assessment techniques.

This paper describes method which experimentally reproduces the most prevalent bearing fatigue failure modes experienced in ball and roller bearing applications. Generally, bearing fatigue life is divided into two groups. One is a surface-originating type of fatigue. The other is a subsurface-originating type of fatigue. The mechanism of each type of fatigue has been studied. Bearing materials were developed for long-life based on the study of the mechanism of fatigue. However, the condition of the evaluation method, or life test, may be different from the actual application conditions. For instance, the subsurface-originating type of fatigue is tested under extremely heavy loads. The surface-originating type of fatigue is tested with severely contaminated lubrication. There is the possibility that the evaluation methods do not simulate the failure modes that are actually present in the field.

The aspects of real engineering surfaces are discussed with regard to their three-dimensional nature. A review of potential uses of surface finish measurement methods are discussed for characterization of functional surfaces. The use of an optical-based system and measurement procedures are discussed as a means of differentiating surface roughness and its texture of functional surfaces by surface engineering parameters. Using an optical-based system and a set of specific measurement procedures, two functional surfaces with different roughness were analyzed to illustrate a typical surface topography evaluation. A simple sliding test is then utilized to show that a special finish produced by a proprietary finishing process can provide improved performance, as measured by wear differences, frictional properties and operating temperature of the system.

Fatigue life of the 6206 deep groove ball bearings has been evaluated under various thin lubricant film conditions. Endurance testing demonstrates that the fatigue life is remarkably longer than previous formal experiments. In addition, examination of flaked areas showed some to have subsurface origins, even after testing with extremely thin lubricant films. Longer fatigue life has been attributed to improvements in bearing steel quality, as well as improvements in the surface roughness of the ball bearing raceways. With thin lubricant films, the film parameter Λ, and the roughness profile have a greater influence on ball bearing fatigue life. Qualitative analysis of the rolling contact surfaces of some of the bearings after test has been carried out, and the formation of oxidized and carbonated films has been detected. These films can be considered to be contributors to longer fatigue life.

This report is concerned with the effects of braid angle on the behavior of hydraulic hose. For equilibrium conditions to exist, and if the braid layers are assumed to bear tension forces only, the angle of the reinforcement layers must be along that of the total force exerted by the internal pressure. This is the neutral angle θN, which has a theoretical value of 54.74° (54°44′). It is possible to hypothesize a fretting wear model in which wires move on top of one another inside a braid layer if the braid angle is different from this theoretical neutral angle. Even though theoretical claims are made by some technical professionals, the hydraulic hose industry has been successfully making hoses with non-neutral braid angles for years. Testing and application have shown that fretting wear is not a principal cause of hose failure and fatigue.

In-cylinder heat flux, cylinder pressure, and flame arrival and position data were obtained at air fuel ratios ranging from 11 - 16 at 3060 rpm and approximately 80% load. The engine used was a single cylinder, 5 hp, fixed timing, four stroke, overhead valve, air-cooled engine. Methods of mixture preparation include that produced with the stock carburetor, and with a system designed to provide the engine with a homogeneous mixture (HMS). Heat flux was measured using a thermopile device consisting of 300 thermocouple pairs. A thin film platinum RTD was used to measure the temperature at the thermopile and correct for sensitivity of the thermopile output to thermopile temperature. Flame arrival near the sensor was found through the analysis of an ion voltage signal from a probe located next to the heat sensor. An effort was made to identify and account for the variables which influence in-cylinder heat transfer.

In the hydraulic hose industry, abrasion resistance is an important performance characteristic. The International Standardization Organization (ISO) 6945 Abrasion Standard is typically used to evaluate hose cover abrasion. The purpose of this paper is to determine the effectiveness of the standard for producing repeatable results when weight loss and test to failure methods are used.

Application of a bearing steel requires a knowledge of how the steel will change size at the temperatures of bearing operation, to determine if the changes in geometry will effect bearing performance. The concern is greatest for through hardened steels whose entire volume is subject to expansion from transformation of retained austenite and contraction from tempering of martensite. This paper presents size change data for 52100 and 52100 Mod. II steels for aging temperatures from room temperature to 220°C (425°F), and for M50 and stainless bearing steels aged up to 425°C (800°F). Historic papers establishing the fundamentals of stability in low alloy steels are reviewed. Behavior of high alloy and stainless bearing steels is explained.

For about three decades, the Lambda ratio, i.e. the ratio of Ehd film thickness to the composite surface roughness has been used as an indicator for bearing lubrication as well as the basis for bearing load rating improvement. Although the film thickness and the Lambda ratio are relatively independent of load, the initiation of surface fatigue, or micropitting is load dependent. Furthermore, in the low Lambda region, the bearing surface fatigue and life ratio are more dependent on roughness than on film thickness. This paper reexamines the role of Lambda ratio and other parameters on bearing surface fatigue and bearing life ratio, by taking into consideration the severity of asperity interactions and microplastic deformation,

This paper deals with rack and pinion steering gear with variable ratio, covering the meshing theory, the machining principle and the cutting technology. Based on theoretical results, a new method as well as an apparatus for cutting rack flanks are presented.

The compact Datalink Adapter (DLA) provides the user with the ability to diagnose, monitor and troubleshoot their 1939 based system. With the addition of a Laptop PC, the Datalink is connected into either the serial or parallel port. A Windows based software package completes the system by offering a user friendly environment to conduct the testing.

In the heavy duty vehicle industry, data links allow electronic controllers on a vehicle to interact efficiently to achieve the vehicle's mission. The interactions include sharing sensor data and calculated information, allowing subsystems to influence each other's operation, and communicating subsystem operation state and subsystem configuration. Data links also provide a means for onboard and offboard diagnostic work, including electronic controller identification, reading and clearing diagnostic information, recalibration, and configuration of the controller for the specific vehicle application. The Truck and Bus Control and Communications Network Subcommittee began development of SAE Recommended Practice 51939 to satisfy these needs. This paper presents the serial data communications that have been adopted in the published and draft SAE Truck and Bus J1939 documents: J1939, 51939101, 51939111, 51939121, J1939131, J1939171, J1939173 and J1939181.

Global Positioning Systems (GPS) have introduced to the Construction Industry a new tool with as many possibilities as the Laser presented for increasing the efficiencies, repeatability and accuracy for the contractor. As the industry grows and global positioning systems mature, many applications will emerge from this new tool. This paper discusses merging global positioning with a rotating laser reference to provide an efficient mobile surveying system, as well as a method of automated machine control.