But the specific improvements in plain sewing machines, to which I have had the honor of drawing your attention, do not exhaust the list, and, time permitting, it might be considerably augmented. Nor must it be inferred that advancement has taken place exclusively in those systems of sewing machinery now before us.
The number of special attachments that have been successfully adapted to plain sewing machines has multiplied so rapidly of late, that only one or two of the more notable can be spoken of on this occasion. Perhaps the most generally useful of these is the trimmer, an arrangement consisting of a vibrating knife, which trims off the superfluous edge of a seam as the machine stitches it. These are in extensive use in the factories at Leicester, Nottingham, and elsewhere, while Northampton and Norwich use the same device for paring the seams in boot upper manufacture. The chisel-like knife is usually actuated by a cam rotating with the main shaft, and one or two of the usual forms of this attachment are to be seen here this evening on both lock and loop stitch machines.
When machines are moved by the foot, there are many objections to running the whole machine while winding the shuttle reels. We have, therefore, several useful devices for releasing the balance wheel of the machine from the main shaft, while winding. These are to be found both on Wheeler & Wilson's manufacturing machine and upon Singer's highly finished "Family" machine, which also carries a most ingenious automatic reel winder, capable of doing all the work itself, and ceasing to act as soon as the bobbin is filled.
The setting of the needle in a sewing machine was once quite a task. Ofttimes it had to be adjusted by chance, in other instances by certain guiding marks upon the needle bar. It is gratifying to know that all this has been done away with, and that the needle has only to be inserted into the bar, and fastened by turning a small screw. These are styled self-setting needles, and are usually so arranged that they cannot be adjusted wrongly as to the position of the eye.
In the Willcox & Gibbs machine, and in Singer's single thread machine, shown here, we have an intermittent tension arrangement, which clamps the thread at the right moment, and differs from ordinary tension devices, inasmuch as it may be said to be automatic. The feeder, too, on these machines is of excellent design, while the arrangements that have been introduced into the Willcox & Gibbs straw hat sewing machine are surprisingly effective in spinning up a hat from a loose roll of braid. Speaking of straw hat machines, mention should be made of Wiseman's hand stitch apparatus, as improved by Messrs. Willcox & Gibbs, and shown here this evening. This machine employs two needles, and makes a stitch resembling hand work at intervals, producing a short stitch at the center of the hat, and automatically widening the space between the stitches as the distance from the center increases. The machine itself is of wonderful ingenuity, and must be examined to be understood.
The stitch making itself is, I believe, quite new, and is also of much interest. A pair of needles, the width of a stitch apart, rise from beneath through the material. One of these is an ordinary machine needle, threaded; the other is a barbed needle. After rising above the surface, the loop of the threaded needle is seized by a "threader," and thrown into the barb of the barbed needle. The needles then descend, and the feed occurs, being the length between stitches. Upon the ascent of the needles again against the material, the loop is both given off the barb and is entered by the threaded needle, completing the stitch.
The mechanism of button hole machines is so intricate, that I can only attempt on this occasion to partially elucidate the construction of one of them, recently introduced, namely, Singer's, which automatically cuts, guides, and stitches the work.
Fig. 9 exhibits the stitching made by this machine upon the edge of the button hole. Fig. 10 represents the right and left hand loopers and loop spreaders, and for the stitch making. They rock from right to left with an intermittent motion obtained from a cam. The left hand looper carries the under thread and interweaves it with the upper, forming the stitch, originally invented, I believe, by Mr. George Fisher, of Nottingham, and reinvented for the button holing machine by D.W.G. Humphreys, of Massachusetts, U.S.A., in 1862. The loop spreaders are moved by a roller carried upon the looper frame. Fig. 11 exhibits the feeding arrangement, both sides of the feed wheel, the driving lever, and the shape of the path given to the carrying clamp by the heart cam cut in the upper surface of the feed wheel. The picture on the screen represents the upper portions of the machine, exhibiting the conveying clamp, the to and fro dipping motions of the needle bar, and the parts conveying motion to the arrangements beneath the bed plate. These are shown in Fig. 12, and represent the feed and looper cams, the feeding and looper levers, and the stitch forming mechanism already shown.
A most ingenious device in this machine is the arrangement for automatically lengthening the throw of the feed while stitching around the eye of the button hole. It is effected by means of a cam, which imparts more or less leverage to the feed arm by the intervention of a "shipper" lever, hinged to the feed lever itself. The space of time at my disposal obliges me to recommend a personal examination of the machine itself, to fully understand its various motions and its action in working a button hole.