Search Results

Two high performance industrial machines, the 3400 and 3500 International industrial loader-backhoe, featuring a balanced system of loader integral frame tractor and backhoe design have been introduced to the market. These combinations with matched hydraulic systems optimize operator comfort with machine durability and productivity.

Certain roll over protective structures, ROPS, require resistance to the propagation of brittle fractures at low temperatures. It is demonstrated that the Charpy test is not suitable for characterizing crack propagation resistance. A drop weight test of thin wall tubular specimens was developed which uses a brittle crack starter weld. This test provides an indication of the temperature transition from low to high crack propagation resistance. Because of toughened heat affected zones which can occur in cold formed steel this test is reliable only for hot formed tubes. The temperature transition to high propagation resistance can be determined with precracked Charpy and Dynamic Tear Energy, DT, specimens applicable to cold or hot formed steel. A weld joint simulation specimen was developed to determine energy absorption capacity and low temperature fracture behavior of ROPS joint designs and material.

THIS paper outlines the advantages and disadvantages of present-day hydraulic systems. Included in the discussion are: the blocked return line system for single-acting cylinders, the blocked pump inlet, and the basic open-center-valve system. More advanced designs mentioned are: open-center-valve systems with cylinders in series and with parallel cylinders, close-centered valve systems with pressure regulator, and the central hydraulic and accumulator systems. The author points out that the advantages and disadvantages of each system depend to a great extent upon the design in which it is used.

The purpose of this paper is to define the important considerations facing the chassis designer in selecting a power-plant for a heavy duty vehicle. An assessment of the merits and demerits of optional approaches to the problem is made. Future trends in the factors determining powerplant selection are discussed.

A study to define accurately and discover new parameters of productivity for the contractor has resulted in a new design concept in off-highway trucks. This new concept has been first applied in the International Model 180 Payhauler, a rear dump vehicle of 45 ton rated capacity. The function and form criteria are discussed by components and systems in terms of the complete vehicle and on the job applications.

As the American farmer continues to substitute capital and technology for labor, his need for more powerful tractors will increase. Utilization of this increased power can be achieved by the use of tools with greater working widths, performance of several combined operations in one pass, and increasing the field speed at which the various operations are performed. This paper explores some of the advantages (and disadvantages) of high tractor field speeds, first from the farmer's viewpoint and second from the engineer's or manufacturer's viewpoint.

Five geometrically similar bulldozer blades, ranging in width 6.45-77.2 in., were tested in four different soil types. Tests were run at low speed and a constant cutting depth equal to 20% of blade height. Horizontal and vertical soil forces, soil force moments, and travel distances were measured. An analysis of the test data is presented and a method of predicting the draft force of larger blades from tests on smaller scale models is proposed. Test equipment, instrumentation, and test technique are described.

Application of the hydrostatic transmission to a farm and light industrial tractor involved many special design and manufacturing considerations. A brief description of the transmission is given, and some of the special considerations along with their solutions are discussed. Emphasis is placed on the importance of having the proper control system to provide desirable performance and endurance characteristic for the tractor. Because the controls of a hydrostatic by necessity are quite different than for a conventional tractor, particular emphasis is placed on the control portion of the overall development program.

Prior to World War II, most heavy duty highway trucks and tractors were built as Conventionals, i. e., with the cab mounted behind the engine. In the late 1940's cab-over-engine types gained acceptance and in the 1950's the tilt cab COE was developed in its present form including sleeper cabs. The new concept is to combine the best features of conventionals and tilt cab COEs to develop a superior non-sleeper tractor that makes no compromises for sleeper cab types.

Splash and spray conditions created by tractor-trailer combinations operating on the Federal highway system have been studied and tested for many years with mixed results. Past events are reviewed briefly in this paper. In additional testing during 1983, using new state-of- the-art splash/spray suppressant devices, some encouragement was provided that these devices could work. The 1984 Motor Vehicle Manufacturers Association (MVMA) test program was designed to develop practicable and reliable test procedures to measure effectiveness of splash and spray reduction methods applied to tractor-trailer combination vehicles. Over 40 different combinations of splash/spray suppression devices on five different tractors and three van trailer types were tested. The spray-cloud densities for some 400 test runs were measured by laser transmissometers and also recorded by still photography, motion pictures, and videotape. On-site observers made subjective ratings of spray density.

Past experience in the design of construction equipment has shown the importance of being able to assess as accurately as possible the predicted life of a machinery's structural components. A procedure is described wherein, through proper initial planning of tests, data may be obtained that will facilitate the prediction of future component designs. From the information secured, it becomes possible to graphically relate a component's stress-time history and thereby arrive at a suitable requirement for a new design.