A great reduction in the prices of clothing has been caused by the use of manufacturing machines. This is especially marked in the production of shoes, whose output has been enormously increased since the invention of sewing and other machinery. While shoe-sewing machines do. not strictly fall within the scope of the present section, we may be permitted to include a description of one example and also of a book-sewing machine, both of which are among the most important manufacturing machines of the present tine, and which are typical of American ingenuity.
mechanical sewing of boots and shoes was for some time done on machines similar to the ordinary leather sewing machines, but these did not satisfactorily reach the inside of the shoe to sew the " upper " to the " insole," although the soles could be sewed together by stitches put on the outside. The machine illustrated in Figure 4, in which a device at the end of the horn is made to act in conjunction with a hooked needle piercing the sole from the outside, seems successfully to fulfil the requirements. A large spool of thread coated with shoemaker's wax is attached to the rotating horn, through which the thread passes to a " whirl " at the tip of the horn. The whirl is a small ring through which there is an opening for the passage of the needle and having bevel teeth on the exterior, so that it can be rotated by a pinion which receives its motion by rods and bevel-gearing communicating with a cam movement in the rear of the upper part of the machine. During the descent of the needle through the centre of the whirl, the latter makes a partial revolution, carrying the thread with it, the effect of which is to throw the thread into the barb of the needle. In preparing a shoe for the machine the tipper is fitted to the form or "last" and to the insole, and the outer sole is then tacked on. The shoe is then placed on the horn and the stitching is begun, preferably near the shank. As the stitching proceeds the horn is rotated, and the shoe is moved thereon so as to bring it properly under the action of the needle. The needle, after penetrating the sole, has the waxed thread laid in its hook by means of the whirl, and in ascending draws a loop of the thread through the sole and the turned edge of the upper. A cast-off closes the hook and prevents the escape of the loop, while the shoe is moved for a new stitch. When the needle again descends it passes through the loop on its shank and draws a new loop up through the loop previously formed, thus enchaining- one loop with another. The horn is kept warm by a lamp or by gas, which tempers the wax on the thread as it passes the horn.
Figure 5 exhibits a machine for webbing the linings and for staying the shoes. It is of the Willcox Gibbs system, with double needle-bars, which are actuated by a single vibrating arm and fed from two spools, making two parallel rows of stitches. The tape is supplied from a roll placed on a bent rod or carrier above the machine. Figure 6 is a
machine for overseaming the edges of blankets.
Book-sewing Afachincs are now largely employed to stitch together the sheets or "signatures" which make up the body of a book. These machines are remarkable not only for the great ingenuity of their con struction, but also for the rapidity with which they operate and for the strength of their finished work. The Smyth machine is capable of sew ing sixty signatures per minute, and inserts when required eight separate threads, any one of which may be cut or broken without impairing the holding of the others. In this machine each of the signatures is hung upon one of the horizontal arms of a four-arm reel, which presents the signatures in succession to the action of the clamps and the operation of the needles. The signature is secured by the clamps, the arm drops away, makes a quarter revolution, rises, and presents the next signature.
Embroldoy-machine•—Closely allied to the sewing-machine is Heil mann's embroidery-machine (fit. 55, fig-. 7). In this machine the needle, with a central eye, is guided in the manner illustrated in Figure 2 (fii. 53), but its great capacity is attained by the simultaneous movement of a large number of needles (from two hundred to five hundred, arranged in two horizontal rows), each of which repeats the flower or device on a piece of silk or other material from one governing design. The material to be embroidered is stretched smoothly in a vertical frame, which is movable in every direction in its own plane. Before each passage of the needles this frame receives a motion corresponding to the interval between two adja cent stitches, from a pantograph by means of a style called a " point " set further forward upon the design by the operator. Running on horizontal rails in front of and behind this frame are broad carriages which carry a small nipper for each needle. All the nippers of each carriage can be simultaneously opened and closed by a simple mechanism operated by the attendant, so that all the needles can be liberated or grasped. From the above description the working of the machine can readily be understood. The needles, threaded through the central eye, are passed into the stuff by the advancing carriage on one side, while the of the carriage on the opposite side seize the presented needles and pull them sufficiently through to tighten the threads. The frame is then shifted according to the requirements of the pattern, the needles are again passed through in another place, and, being seized by the nippers of the first carriage, are drawn tight; the frame is then shifted the interval of one stitch by means of the pantograph and the operation is repeated.
As will be seen, the capacity of this machine is based on the fre quently mentioned principle of the duplication of the tool, the moving by natural forces, as in the case with the sewing-machine, being, however, impossible.