MECHANICAL DRAWING: see DRAWING, ENGINEERING. MECHANICAL ENGINEER. By the beginning of the 19th century the development of the steam engine had resulted in a large increase in the size and number of machines in operation and the factory system was beginning to appear. The millwright and smith were not competent to devise and construct the new machines and consequently the profession of mechanical engineer came into being. The name of mechanical engineer became com mon about the middle of the century. The British Institution of Mechanical Engineers was founded in 1847. About 1890 the field of mechanical engineering was restricted by the separation of the important field of electrical engineering. The field of the mechani cal engineer comprises (I) power generation and transmission, (2) transportation of both men and goods, including railway, marine, automobile and aeronautic, as well as hoisting, conveying and pumping and (3) production, which includes machine tools as well as the final products of manufacture. Functionally considered, the work of the mechanical engineer may be classified as design, construction, operation, research, invention, maintenance and sales. The great majority of mechanical engineers are employees of organizations engaged in production or transportation; a small percentage only is engaged in the private practice of their profession as consultants. In the United States, the education of the mechanical engineer is normally by a four-year undergraduate course in a degree-granting college or university. On completion of the course, a large percentage of the students enter the employ ment of industrial organizations as apprentices for a period of one or two years ; in most of the larger companies this work is organized so as to give opportunities for gaining experience in various departments, with about three months spent in each. In Great Britain, most of the universities grant degrees in en gineering but only a small fraction of the engineers are trained in them. The normal preparation for the profession is by a five year apprenticeship. Theoretical instruction is obtained by eve ning work at local technical institutions, of which there are about I 5o. These institutions usually grant diplomas on the completion of a prescribed course. In Scotland the university instruction occupies about six months of the year and it is customary for the students to alternate between study and work during the appren ticeship. In England, this alternation is not usual, and apprentice ship follows the completion of the university work. In Germany the conditions are in general similar to those in Great Britain. (L. S. MA.)
MECHANICAL HANDLING. Before mechanical han dling became an important operation in all industries a variety of appellations were assigned to machines for such purposes. At first the designation most favoured was "labour saving devices," be cause it was applicable both to the mechanical and to the econom ical aspect ; this designation has now been practically superseded by the one which heads this article. The term was coined in Amer ica about the year 1900, but since 1920 it has been replaced there by the term "materials-handling." The mechanical plant of a modern factory consists generally of two classes of machinery in addition to the power plant ; that for manufacturing a certain commodity, usually by a complex series of operations; and the handling machinery which brings the raw material to the factory, moves it automatically from process to process, and finally conveys the finished commodity to the ware house or forwarding depot. The manufacturing process increases the intrinsic value of the goods; but the mechanical handling op erations do not add to the value of the product and such work must therefore be performed at a minimum of expense.
Mechanical handling devices are divided into two main sections, viz., continuous and intermittent. The former convey the material in a comparatively small but uniform and uninterrupted stream, while the latter convey larger units in intermittent succession. Continuous devices are subdivided into appliances for lifting material, i.e., bucket elevators and appliances for moving material horizontally, i.e., conveyors.
If the inclined disposition is not suitable for the site a jockey pulley can be used to attain the same end, as shown in fig. 1. But for this purpose two endless chains are necessary, which sup port the buckets between them.
In the following brief descrip tions of continuous handling de vices no reference is made to the inclines up or down which they may negotiate. (For this infor mation see diagram, fig. 9.)