SEWING MACHINES. I. MACHINES FOR DOMESTIC USE. —Lock-Wtch _Machines. Tile Wheeler & Wilson ..31achinc8.—In the latest forms of machines of this manufacture the principal improvements consist in the extension of the rotary mode of motion to every part of the mechanism which does not require a different movement ; in devices for inter locking the threads, and for securing uniform feed and exact tension, and also for produc ing ornamental stitchings. The newest family machine (No. 0) is represented in Fig. 1. Motion is transmitted from the upper to the lower shaft by a crank and sliding connection ; pin at the lower end of the latter, working in a slotted crank arm, gives the necessary vari able motion to the lower revolving shaft, and consequently to the rotating hook, thus afford ing sufficient time for the take-up to draw up the loop of upper thread between the casting. off of the loop from the hook and the descent of the needle to form the next stitch, Fig, 2 shows the bobbin of under thread in its case, and the tension spring on the latter. The amount of tension may be regulated when necessary by turning the screw, R, but when once properly set the tension is substantially automatic, adapting itself to the different sizes of thread. Fig. 3 shows the relations of the bobbin and case to the holder and the rotating hook. These parts are brought into proper position by closing the drop, a, which is firmly held upright by the catch-spring, b. Fig. 4 shows the face-plate of the machine and the passage of the upper thread through the thread check, tension pulley, thread controller, and take-up, which last is provided with a roller to reduce friction on the thread, and to facilitate sewing with threads of poor quality.
In the " variety-stitch machine" the loop-taker (or rotary hook) is set with its axis of rotation at right angles to that of the main lower shaft of the machine ; the needle-bar is carried in a swinging gate connected with a segment lever, which is actuated by a cam on the upper shaft, and causes the needle to vibrate laterally one or more times, and to a greater or less distance during each revolution of the shaft, and the feed, by special devices, is made to move forward or backward, to the right or left, or to stand still at each stitch, as may be required. The machine may be used with either one or two needles. By combining dif
ferent numbers and lengths of transverse vibrations of the needle or needles, and different movements of the feed, an almost, endless variety of figures may be automatically stitched, a few of which are represented in Fig. 5.
The Domestic Machine, Fig. 6, has an improved feed mechanism. The lever, A, imparts horizontal vibrating motion to the feed-bar, and receives its motion through the stirrup, B, an eccentric on the shaft and the stitch-regulating mechanism, the lower end of which latter is seen in the form of a groove at C. A projection from B plays vertically m this channel-way, which is so pivoted that an arm from it extending up through the bed, and connected with a scale of distances, may be moved in either direction, thus giving any desired throw to the feed, and in either direction. The feed-dog is regulated in height by the nut, D. E is a thumb-nut to secure the arm wherever located. F is a thumb-nut to fasten the stop, which secures uniformity of stitch, whether feeding forward or backward.
The Willcox & Gibbs Machine in its latest form is represented in Fig. 7. As the parts are all named on the engraving, detailed reference is unnecessary. It has novel means for regulating the tension and the pressure on the material, and for altering the length of stitch.
Combined Lock and Chain stitchMachines.—A novel machine of this class, illustrated in Fig. S. is made by the Domestic Sewing Machine Co. A chain stitch looper is substi tuted for the shuttle, and is attached to the carrier. The second loop is carried around the hook and upon the arm of the looper device, where it is slightly retarded by the tension spring. As it passes off the arm it forms the stitch.
Chain-stitch Machines.—The mechanism of a new machine of this class made by the Singer Co. is shown in Fig. 9. The stitch is formed from a single thread which is inter woven into a chain upon the under surface of the goods. and the tension is capable of adjust ment so that the thread will be drawn closely to the fabric, forming a tight arid flat seam, or left in an elastic chain suitable for knit goods. A beautiful ornamental stitch, resembling braid, is produced by the use of coarse silk or thread.