Search Results

The best weight for a tractor of given horsepower must be a compromise based upon a mean of the many conditions to be encountered by a given machine or by different machines of the same model. While the weight logically will bear some relation to the drawbar pull, the latter in turn depends upon tractor speed. The next item is weight distribution, which requires the utmost skill of the designer; this is elaborated and diagrams are shown of tractors operating in comparatively firm and in soft ground, ascending a grade and when the drive-wheels are mired. The four-wheel-drive tractor requires a modification of the foregoing analysis and the diagrams are applied to afford a similar analysis for this type. The author's conclusion is that, while careful engineering will make the light-weight tractor of conventional type stable under most conditions, there is a possibility that any future trend toward lighter machines will open the field to other types.

Three distinct types of wheel equipment are best able to meet conditions in the field; the pyramid lug, the spade lug and the angle-iron cleat. The author mentions the merits of each type of lug, discusses slippage and states that no one kind of wheel equipment can be recommended as a universal type.

This paper provides an overview of safety situations of commercial vehicles on the basis of databank concerning more than 4500 accidents. Different safety points of view are analysed and evaluated. A special accident reconstruction program (CARAT) is interpreted which is able to solve the traffic and accident questions in practical approach. It summarises conclusions and proposals on road safety of heavy vehicles in Europe.

A photogrammetric transformation is presented, which maps photograph image points to the location of the same points on a nominally plane real surface. The transformation uses 4 base points on the real surface that have known locations and is implemented by an interactive program entitled TRANS4; which runs on MS/PC DOS microcomputer systems. The program addresses three of the five major tasks in the process of extracting geometric data from photographs of a traffic accident site and makes the method a realistic option for investigators. The two other tasks are also discussed. The character and relative magnitude of several errors associated with the transformation are discussed, along with techniques for managing the errors.

The author surveys some of the general conditions prevailing in the street-railway field and the prospective development of a new type of service, in discussing the necessity for closer cooperation between the engineers of the automotive industry and the operating organizations of the railways, the idea being to develop flexible transportation-equipment that will coordinate with the operation of present railway-transportation facilities and to promote the utilization, wherever feasible, of railway power-supply in the employment of flexible bus-type equipment in supplementing and extending railway-organization service. Changing conditions are outlined, the influences tending toward flexible equipment are stated, and the differences of engineering practice pertaining in the railway and automotive fields are commented upon to show wherein railway and automotive engineers can cooperate.

PRESENTED here is a method of correlating job requirements with truck performance, so that the best possible truck will be specified for the application. The result of following this procedure, the author claims, is to obtain maximum performance of the vehicle at minimum cost.

The popular view of the life of a commercial truck driver is one of excitement, travel and freedom. It is also mostly wrong. Heavy truck driving is difficult, exacting, often dangerous work. This paper details some of the hazards which face the person behind the wheel, and some approaches to improving that unique workplace.

THESE down-to-earth speculations by Mr. Bachman should help to clarify for all their picture of the truck of the future. Mr. Bachman considers such a detailed but important item as increasing the overall width up to the rear fender top line to 102 in. from the 96-in. Figure now adhered to in all but two states for the maximum width at any point, but keeping the width of the cab at 96 in., because in traveling along the highway, the cab actually takes up several more inches, anyway. These extra inches across the fenders would allow improvements to be made in tire mounting, spring suspension, riding qualities, stability, and braking. Other changes foreseen by Mr. Bachman include: increases in weight and horsepower, allowing for faster and more efficient transportation, especially on the first-class highways planned by the Federal government for connecting all large cities and most small ones; more comfortable cabs for the driver; and quieter operation.

Truck Frame Siderail Design The recent development of high strength steels for truck frame usage has led to a refinement of the section proportions of conventional channel siderail designs. To enable the frame designer to fully utilize the availability of high strength steels, to reduce the weight of truck frames and increase their durability, new design criteria must be established. This paper highlights the basic design alternatives from which the frame designer can design improved frame assemblies utilizing high strength steels.

THIS paper outlines tests made to verify the SAE recommended practice for estimating truck ability performance described in TR-82. The author has collected data on four vehicles and compares it with the results computed in TR-82 and with a Method X. The data includes information on air and rolling resistance, effect of wind velocity, chassis friction power, grade ability, and the like. The author concludes that the SAE method of TR-82 is at the present time the most reliable method for computing truck ability.