Patent GB-910277-A (GB)
Title: Improvements in sewing machines
IPC: D05B73/00
Filed: 1961-06-19
Abstract: 910,277. Sewing-machines. SINGER MANUFACTURING CO. June 19, 1961 [June 28, 1960], No. 21977/61. Class 112. To remove severed sewing threads from the loop-taker a sewing-machine is provided with a cover, beneath its work-supporting bed, forming a chamber enclosing the looptaker, and is further provided with an air intake port in the cover above the axis of rotation of the looptaker, an air exit port in the cover situated below the level of the inlet port and poweroperated means for evacuating air from the said outlet port. Stands.-The sewing-machine 11 is mounted on a base 12 supported on a table top 24 sustained by leg structure 25 which also supports treadles 26, 28 which are respectively operable for starting the machine and opening and closing the work clamp 19. The driving motor 23 and the air blower unit 102 are supported beneath the table top. Single-thread lock stitch; rotary hook construction; bobbin winding; thread cutting.- The loop-taker is of the type in which thread from a needle thread supply may be wound on a bobbin within the looptaker for subsequent use as bobbin thread in the formation of single thread lock stitching. The hollow shaft 31 carries a cup-shaped looptaker body 32 formed with a beak 34 (see Fig. 4). A bobbin 38 (see Fig. 3) is journalled on a bobbin case 35 held stationary within the body 32 by a finger 36. When a rod 40, in the hollow shaft 31, is moved to the left in Fig. 3 by cam means, not shown, the winding member 41 carried by the rod clamps a needle thread loop on the hook beak 34, directs the loop to the bobbin 38 and rotates the bobbin to wind the thread thereon. The rod 40 is then retracted to the position shown. After completion of the stitching, mechanism associated with the looptaker draws any unused thread from the bobbin and further mechanism cuts the thread. To this end a slide bar 50 is moved lengthwise by cam means (not shown), a cam finger 52 extending from the bar engaging a circular spring 54 secured to the rear of the looptaker body, an auxiliary hook 55 on the spring being thus moved from a retracted ineffective position to a position where it can engage the bobbin thread. An arched finger 53 moving with the cam finger 52 moves to a position across the bobbin thread engaged by the hook 55 and, on retraction of the slide bar 50, will draw back the bobbin thread across the periphery of the looptaker flange 33 (Fig. 5, not shown). The slide bar 50 also carries a rack 60 (see Fig. 4) meshing with a gear segment 61 journalled in a bracket 37. A thread severing blade 62 and associated thread camming finger 63 are secured to and turn with the gear segment 61. A cam groove 65 in the segment 61 is engaged by a follower 66 carried on a pivoted arm 67 associated with a thread pick-up finger 68 which moves as the segment rotates to enter a notch 69 (see Fig. 3) in the bobbin case to engage the last needle thread loop which runs up the finger (Fig. 5, not shown) for severance by the blade. Frames, removing severed threads by air currents.-The work-supporting bed of the machine is provided with a bottom cover 79 formed of sheet material and fastened to the bed by screws passing through elongated slots 84 (see Fig. 7) which provide for movement of the cover towards the free end of the bed to allow clearance for depressing the cover to give access to the looptaker. The cover is cut away at 91 to provide an air inlet port. A tube 87 entering, and welded to, the bottom of the cover has an upper portion flattened to provide a partition 88 which is also welded to the cover. An aperture 90 disposed below the level of the looptaker at the side of the looptaker at which the latter turns downwardly, and on the opposite side of the cover to that in which port 91 is provided, forms an air exit port through which air is withdrawn by the blower 102 by way of the connecting tube 100. The disposition of the apertures at 90 and 91 provide a circulation of air in the direction of rotation of the looptaker to clear the severed bobbin thread ends from the looptaker into the tube 87, through the blower and into the mesh bag 108 detachably secured to the blower by spring clips 109.