Patent GB-190827964-A (GB)
Title: Improvements in Sewing Machines.
Inventor: FAIRWEATHER WALLACE
Filed: 1908-12-23
Granted: 1909-05-20
Abstract: 27,964. Fairweather, W., [Singer Manufacturing Co.]. Dec. 23. Hem - stitching machines. - In a universal feed machine for hemstitching, the needle - bar carrying two pivoted needle-holders, the piercer, and the feed foot, are carried by a frame capable of swinging about pivots in the line of feed within a revoluble cylinder. Complimental looptakers and a throatplate are mounted below the worksupport on a frame which is geared to revolve with the cylinder. Handgear for rotating these parts is provided with automatic locking devices, which prevent rotation except at the completion of hem - stitch groups. Other devices similarly control the stop-gear. The needles are placed at a distance from the axis of the revoluble cylinder to ensure the formation of satisfactory corners when the direction of the hem is abruptly changed. A tubular needle bar 18, Fig. 9, is mounted centrally in a frame 21, and upon a crosshead at its lower end two needle-holders 38, 39 are pivoted. The needle-bar is reciprocated by parts 7, 8, 9, Fig. 3. The needles are pressed towards one another by a compressed spring 467 placed between pivot blocks 455, 456, on the upper ends of extensions 459, 460 of the needle-holders. These blocks are also pivoted to levers 448, 449 pressing upon the cam sides of a rod 445, which is continuously reciprocated and so imparts lateral vibrations to the needles. The rod 445 receives its movements from a sleeve 438, Fig. 3, on the cylinder 22, which is actuated from a cam-groove 427 in a cam-disk 254 by a usual double lever 440. The cam-disk is secured to a shaft 256, which is rotated once for every three stitches or for every complete hem-stitch group. The piercer 300 is carried at the foot of a bar 328, slidably mounted on the frame 21, which is reciprocated once for every hem-stitch group by connexion with a sleeve 314 on the cylinder, which is operated by a camgroove in a second cam on the shaft 256. The feed foot 350 is attached to a rod slidingly mounted in the frame 21 and pressed downwards by a spring. The feeding movement takes place while the piercer and needles remain in the work, and is occasioned by swinging the frame 21. For this purpose, two levers 364, joined together at their lower ends, carry a block which engages part of the frame 21 and are pivoted inside the cylinder, the inclined ends 373 projecting through slots in the cylinder and over the upper edge of a sleeve 361. The sleeve is reciprocated upon the cylinder by a cam-groove in the cam 254 on the shaft 256, and in contacting with the levers 364 rocks them and so swings the frame. After the feeding movement, the piercer and needles are raised from the work, and a projection on the piercer bar engages the shank of the feed foot and lifts that also. A presser-foot 281, Fig. 3, hereinafter described, is lifted during the feeding movement by a groove in the cam 254. The thread bobbins, tension disks 159, Fig. 3, and thread-controlling springs 160, are carried by a plate 156 mounted on a bracket 150 and geared to revolve with the cylinder 22. The threads pass down through a central hole to the eye of a take-up arm 179 pivoted on a fixed bracket 2. From the take-up, the threads pass down the tubular needle-bar and emerge through a hole in it at its lower end. The loop-takers 63, 64, Fig. 3, are secured to the upper ends of quick-threaded screwed spindles 75, 76. These are mounted on a revolving frame 87, and are threaded through an operating-disk 55 which is reciprocated by lever connexions 45, 43 with the main crank 8. The needle throat plate 213, Fig. 7, in order that it may move with the piercer and needles in the feeding movement, is slidably mounted between plates 211, 212 on a table 206 secured to the revoluble frame 87. It is pressed into its normal position by a spring 220. To ensure that rotary movements shall be given to the cylinder 22 and the frame 87 only at the completion of hem-stitch groups, the operating-shaft 100 is provided with a V-grooved wheel 498, which rotates between two brake blocks 487, 488, Fig. 15. These blocks are carried by levers 479, 480, which are pulled together normally by a spring 499 so as to lock the shaft from rotation and are separated to free the shaft at the completion of each hem-stitch group by cams on the shaft 256. The main shaft is driven from a belt pulley 529, Fig. 25, by means of a disk 525, and a plate 528, which grip between them a leather ring 530 secured to the pulley. The plate 528 is pulled towards the disk 525 by springs 527 surrounding screws 526. Two disks 540, 552 are free to rotate on the shaft, and are provided on their adjacent faces with complimental ratchet-shaped teeth. When these disks rotate relatively from their normal position, by reason of the ratchet-shaped teeth they are moved away from one another. Thereby, in the first place, the disk 552 presses upon the projecting heads of the screws 526 and separates the disk 525 and plate 528, and disconnects the shaft and belt pulley. In the second place, the disk 522 bears upon the friction surface 566 carried by the disk 525, and the disk 540 by the thrust pins 538 presses the plate 537, which is held from rotation, on to the friction disk 536 secured to the shaft, and so brings the machine to rest. The disk 540 is anchored by an arm 543, Fig. 14, integral with it which is held up to a nut 551 by a spring 556. The disk 552 has an arm 555 to which is pivoted an L-shaped lever 560 having a brake shoe 561 at one end and a roller at the other, which engages a slct 563 in a lever 564 pivoted to the machine frame. The lever 564 under the pressure of a spring coiled about its pivot always tends to rise, but, normally, is hindered from so doing by a stop 508, Figs. 3 and 15, which projects into the path of an extension 565 of the lever 564. The stop 508 is linked to a lever 502, and by that lever a cam withdraws the stop at the completion of each hem-stitch group, thus leaving the lever 564 free to rise. In rising, the lever forces the brake shoe 561 on to the disk 525, which causes the disk 552 to rotate relatively to its companion disk 540 and so stop the machine. The machine is positively stopped in a predetermined position by the brake shoe contacting with the projecting part 588 of the disk 525. The lever 564 is linked to a lever 581 on the hand-crank 106, and the handle 107 of the crank being slidingly mounted on its own pin is connected to it. By these means, the machine is started and kept running by pulling the handle down into, and holding it in the position shown, in opposition to the spring on the lever 564. The machine is stopped when the handle is released. The presser foot 610, Fig. 34, is shod with a rubber ring 609 of plano - convex cross - section. When sprung into place, it assumes the shape shown, and, as it is flattened out when pressed on to the work, it stretches in all directions the work beneath it. Fig. 31 shows the position of the stitches at a corner as produced when the needles are placed out of line with the axis of the cylinder. If the needles were in line, the stitches c, made after the direction is altered would be in a line with the point mid-way between the last stitches a, b. The out-of-centre arrangement places the stitches c, d in line with the outer edge of the former stitching and so effects a better corner.