This section is from the "Modern Machine Shop Construction, Equipment, And Management" book, by Oscar E. Perrigo. Also see Amazon: Modern Machine Shop Construction, Equipment, And Management.
Its importance in the modern machine shop. Careful planning necessary. Continuous progress of work through the different departments. What may be classed as transportation facilities. Traveling cranes. Overhead trolleys. Shop tracks. Yard car crane. Shop trucks. Portable crane. Yard tracks and cars. Cast iron track. Requirements of a floor track. An economical system of shop tracks and cars. Overcoming wheel friction on curves. Forms of wheels and track. Dimensions of track. Switches. Track timbers. Yard tracks. Track for shop floors. The turntable. Shop cars. Construction and dimensions. Various forms of shop cars. With removable stakes. With removable boxes. With racks for special work. With trays for special work. Dump car for coal, sand, etc. Double car, two cars and a special platform. Varying dimensions of cars. Number of cars necessary.
The question of the transportation of stock and material from the point of its receipt from outside sources to the various departments where it is to begin its regular transit from the raw material to the finished product, of transferring this material from one department to another during its progress through the shops, and of its final transit from the department where it is finished to the storehouse, for safe keeping or for shipping to customers, is an important matter. For if closely followed through all its various stages, and the expenses accurately kept, as to the capital involved in the appliances necessary, the proper maintenance of these facilities in good working condition, and the labor necessary for their successful operation, it would appear to be a far larger item of expense in the general account than would usually be supposed from a superficial consideration of the question.
This is a matter upon which careful planning is needed in all its bearings, as any saving in this respect, while still rendering good service, is an actual saving, and, unlike the reduction of the cost in building a machine for the market, is not liable to effect a deterioration of the real quality or value of the product. This does not mean that the service can, or should be, made inefficient in order to avoid expense, but rather that it should be well planned, well administered, prompt and efficient in every way, yet without a useless appliance or an unnecessary man employed in it. For instance, the progress of the work through the different departments should be so arranged that, as far as possible, it may be really progressive from the raw material to the finished product, with as little retrograde movement as may be. In this way a considerable percentage of the work of transporting materials and stock in progress may be saved, rendering a less extensive equipment of cars, trucks, etc., necessary, as well as a smaller force of employees for handling them.
In arranging the different departments of the plant here shown due consideration was given to this matter and they were carefully planned with this end in view, as will be more fully pointed out in the chapters on Machine Shop Management which will succeed this part of the work.
In the list of appliances that may be classed as transportation facilities, we may mention traveling cranes, overhead trolleys, shop cars on tracks, cars on yard tracks, hand trucks, and small tool conveyors. Of these, the traveling cranes may be those propelled by a shaft running the entire distance of their travel, by those carrying an electric motor for their propulsion, and those of small capacity worked by hand, with a chain reaching down near the floor. Again, as to lifting power, they are operated by the shaft above mentioned, by a motor, or by chain blocks with the usual differential chain wheels or other similar device.
Overhead trolleys running on I-beams may have a small motor mounted upon them furnishing the power for their propulsion as well as for their lifting power. Frequently those of moderate capacity are pulled along by hand, and the loads lifted by chain blocks operated by hand. These trolley tracks are so constructed that they can be put up in straight lines, curves, switches, crossings, etc., which render them very convenient for light work, and they occupy but little room overhead, and none at all on the floor. In some cases, however, existing overhead obstacles such as shafting, belting, countershafts, etc., preclude the use of either the overhead trolley or the traveling crane; in others the weights are not sufficient to demand the expense of a traveling crane; in still other locations several traveling cranes would be required to cover the space to be operated in. Then there are other situations in which lack of height prevents the use of the overhead trolley system.
Shop tracks for the accommodation of cars of the usual size, say 34 inches wide and 5 feet long, will be of the same gage as the yard tracks, or about 220 inches, so that the shop cars or heavier and larger yard cars may be used on the whole system. These cars may be propelled by small electric motors in the form of an electric locomotive, which is simply a car fitted with two motors operated by a storage battery, but more often they are pushed about by hand, particularly when loaded with less than 2 tons weight.
A balance crane may be erected on a car for yard or shop use, and may by this arrangement be capable of picking up and carrying a load up to a ton or two. It is very useful in locations where power for loading is not available.
Four-wheeled shop trucks, with the front axle pivoted and handled by a tongue, should have their wheels so constructed and located as to properly run upon the shop tracks as well as upon the floors.