Patent GB-190406288-A (GB)
Title: Improvements in and relating to Feeding Mechanism for Sewing Machines.
Inventor: NOBLE DONALD
Filed: 1904-03-15
Granted: 1904-04-21
Abstract: 6288. Noble, D. March 15. Feed; presser-feet; presser lifted automatically ; needle-driving.-Relates to sewing-machines of the type in which the feed of the material is effected by mechanism mounted above the work-support in the overhanging arm as described in Specification No. 5975, A.D. 1900, the object being to increase speed and decrease noise, and also to regulate automatically the quantity of bobbin thread supplied at each stitch. An eccentric 7, Figs. 1 and 6, is surrounded by a band 9. To the band is pivoted a lever 12, Fig. 9, at a point 13, and the other end of the lever is pivoted at 14 to a bellcrank lever 10 which is pivoted at 11 to the casing. To the shorter arm of the lever 10 is pivoted, at 15, a block 16 which slides in a slot in a T-shaped lever 18. The lever 18 is pivoted at 19 to a collar 20 fixed to the tubular presser-bar 21, Figs. 1 and 9; and into a slot 44 in one arm of the lever slides a block which is pivoted at 42 to the inner side of a collar 38 on the feed-bar 35. The latter slides, together with the needle-bar 26, in a frame 23 which oscillates about an axis 24 in the casing. As the cam rotates, a rocking motion is imparted to the lever 18 which causes alternate raising and lowering of the presser and feed bars, the downward pressure exerted by a spring 67, Fig. 15, on the presser-bar being transferred, when the latter is lifted, to the feed bar. The spring 67 engages at one end a threaded rod 69 in the end of a sleeve 68, which is tapped within the upper part of the casing 2. At the other end it engages the presser-bar 21, the tubular end of which is also fitted into the sleeve. A tongue 70 on the collar 20 works in a vertical slot in the casing preventing twisting of the bar. Fig. 6 shows the mechanism for oscillating the frame 23. A middle link 54 is pivoted at each end to a lever 46 and link 57, the latter being equal in length to the link 54 and pivoted to the oscillating frame. The lever 46 is pivoted by a stud 49 to the casing, the stud being provided with a wrench hold for a lever outside the casing. This lever, by rotating the lever 46, regulates the distance apart of the studs 55, 58, and, by thus controlling the amplitude of oscillation of the frame, regulates the length of stitch. An arm 65, pivoted to the junction of the links 54, 57, has a roller stud 62 at its upper end which is moved by the eccentric band 9 in a stationary slot 63, Fig. 1, on the casing. The arm 65 is thus lifted, and, by operating the links below, causes the frame 23 to oscillate, feeding the material when the feed-bar 35 is pressing on, and the needle is within, the material. The needle-bar is caused to reciprocate vertically by means of a rod 27, one end of which is pivoted to a collar 28 on the needle-bar, and the other pivoted at 29 to the eccentric 7. The collar 28 is provided with a flattened extension 30 which projects and slides within a slot 31 in the oscillating frame, thereby preventing twisting movement of the needle-bar in its bearings. The extension 30 is split, and has tapped in it a tapered screw bead 34 by means of which wear may be taken up. A similar device is used in connection with the feed-bar 35, Fig. 1. Governing under thread; lock-stitch hook sewing- machines ; work-supports.-Fig. 5 shows a mechanism in which, by adjusting the position of a finger 86, mounted in the sleeve 85 by means of a screw 87, the length of thread taken from the bobbin case 93 for each stitch may be regulated. Set-screws 91, 92 are tapped in the forked sections 89, 90 of the sleeve 85, which is mounted on a rock-shaft 81, so as to grip a lug 88 on a lever 83 and enable the position of the finger 86 to be adjusted relatively to the lever 83. The slotted end of this lever engages a cam 84 on a shaft 76 which is driven by a band from the main shaft. The finger 86 is thus caused to oscillate. On the same shaft 76 is mounted a toothed wheel 75 which meshes with another 74, on a shaft journalled in bearings 73, this shaft having the loop-taker 33 mounted on it. To prevent the under thread from becoming entangled in being drawn from the bobbin-case, the upper end of the finger 86 is sheltered within a groove in the underside of the throat-plate 45. The needle aperture 97 is made elongated to admit of the feed which is effected by the needle when the feed-bar is down, and the forward movement of the finger 86 occurs when the presser-foot 22 is down on the material, binding the previous stitches in place, and preventing puckering of the material.