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.
For instance: In a large plant of one floor, it may not be convenient to locate the tool room near the center of the machine shop for the purpose of shortening the lines of travel of the errand boys. Or, if so located, these lines may still be so long as to cause a considerable loss of time. In this case the establishing of auxiliary tool rooms, while of considerable advantage in the distribution of tools, still leaves the transportation problem untouched and out of the question.
Again, in shops consisting of several floors, as many in the crowded cities must necessarily be, the vertical transportation of tools from a general tool room to and from the several floors should be accomplished as quickly and with as little manual labor as may be.
These being the conditions, it becomes necessary to devise a system of transportation that will accomplish the required results in as economical and efficient a manner as possible, and at the same time occupy as little space in the shop as may be, and that shall not be liable to frequent interruptions from getting out of order. It must, therefore, be some overhead system, when used for horizontal transportation; it must be simple and of as few parts as possible so as to be inexpensive, and to be less liable to disarrangement; and it must practically take care of itself under all ordinary circumstances.
It is believed that the system herein shown and described, if properly constructed and installed, will fulfil all these conditions satisfactorily. In the engravings accompanying this description, Figs. 86, 87 and 88 represent the system of horizontal transportation, and Figs. 89 and 90 that for vertical service. The horizontal system consists of a half-inch braided cotton sash cord, fitted with metal couplings and passing over comparatively large sheaves at each terminal.
Upon this carrying cord are suspended hanging receptacles of suitable form and dimensions for holding the tools to be transported. Fig. 86 is a side elevation of the fixed terminal, the shaft b, upon which is fixed the main sheave B, being journaled in the hangers A, one of which is of sufficient length to furnish a bearing for the shaft, while the other has formed upon it a curved arm a, in the outer end of which is journaled the sheave C, for the purpose of supporting the carrying cord d, at the point where the carrier leaves the cord in coming to rest. Fixed to the extending arm a is an inverted U-shaped piece of sheet metal D, covering the carrying cord d, and furnishing a resting place for the carrier. This carrier is composed of a box E, of sheet or cast metal, with a curved bottom as shown, and suspended by the malleable iron supports F F. These are shown in end elevation, the supporting sheaves in section, in Fig. 89, which shows the supporting sheaves G G and the bracket H, on which they are journaled. This device is also shown in front elevation in Fig. 87. This supporting device should be located at suitable distances along the line according to the loads to be carried, but always near enough to each other to prevent undue shocks as the carriers pass over the supporting sheaves.
Fig. 86. Fixed Terminal Hanger of Horizontal Tool Carrying System.
Fig. 87. Intermediate Support and Adjustable.
Fig. 88. Terminal Hanger of Horizontal System.
Figs. 89 and 90. End View of Intermediate Support for Horizontal Transportation, and Carriers, Vertical System.
The carriers shown are of simple form and will be most useful for carrying the usual variety of small tools. Any convenient form may be used, however, the center of gravity being always kept directly under the carrying cord d. They may be made with considerably less drop from the carrying cord, for most kinds of tools, this distance being reduced nearly one half, which will cause them to move with less shock and less of the swinging motion as they pass along. They should never be relatively lower from the carrying cord than is here shown.
Fig. 88 shows the adjustable terminal hanger K, and its connections. In this case two hangers are cast on a plate L, or permanently fixed to it, one of them having a projecting arm k, carrying the supporting sheave P, and being provided with the U-shaped cord shield n, similar to that shown at D, Fig. 86. The plate L is arranged to slide upon the plate M, and is secured to it by two bolts as shown. The adjusting screw R is provided for taking up any slack that may be in the carrying cord d. The main sheave, J, is fixed upon the shaft j, which is journaled in the hangers K.
In operation, the device is driven from a pulley of suitable size on the shaft 6, and at such a speed as will give sufficient momentum to the carrier E, to cause the carrier arms F F to ride up on the whole length of the cord shields D and n, and stop there with very little shock, the carrying cord running in the direction of the arrows. In use the carriers have only to be taken off and hung upon the returning portion of the carrying cord to return the empty or loaded carrier. Upon the arrival of a carrier it glides up on the cord shield D or n, and remains there until removed. Should a second carrier arrive before this one is removed no harm is done, although it is expected that they will be removed as soon as they arrive. The cord shields D n may be made long enough to accommodate two carriers, but this will seldom be found necessary.