Patent GB-871168-A (GB)
Title: Needle threader for sewing machines
IPC: D05B87/02
Filed: 1958-07-18
Abstract: 871,168. Sewing machines. SINGER MANUFACTURING CO. July 18, 1958 [July 23, 1957], No. 23112/58. Class 112 A sewing machine comprises a slidable and rotatable needle-threader bar which is parallel to the needle bar and carries a threader finger, means for positioning the threader bar relatively to the needle bar whereby on turning of the threader bar said finger will pass through the needle eye, and means for preventing turning of the threader bar except when said finger is aligned with the needle eye. The needle bar 3, which is journalled in the bottom wall 2 of the machine head, carries a collar 18 connected by a driving pitman 16 to the arm shaft. The needle 4 is positioned vertically in a clamp 9 by abutting a transverse pin 11. A threader bar 20, journalled in wall 2, is formed at its upper end with an axial bore 32 and with opposed axial slots 33 which are shorter than bore 32. A plate-like member 36, disposed in slots 33, has a lower portion 37 equal in width to the diameter of bar 20 and wider upper portion projecting radially from the latter in the form of flanges 39. A handle 40 projecting from the upper end of member 36 normally passes through the vertical leg 50 of an L-shaped slot 50, 51 in a fixed plate 45. A tension spring 43 connected between a lug 44 on plate 45 and the lower end of a slot 42 in member 36 biases the latter against a collar 47 on the upper end of bar 20 to maintain bar 20 in the raised position. A compression spring 41 is interposed between member 36 and the bottom of bore 32. A sleeve 27 slidable on the needle bar is connected to a flange 28 slidably positioned on bar 20 below wall 2, and flange 28 is connected by a bar 29 to a flange 30 slidably positioned on bar 20 above wall 2. A radial pin 31 on bar 20 normally engages flange 28 to raise sleeve 27 above the range of movement of pin 11 on the needle bar. To thread the needle the needle bar is positioned near the top of its stroke and handle 40 is forced downwardly to lower bar 20 and sleeve 27, movement of the latter being limited by the engagement of flange 30 with wall 2. For correctly positioning the needle for threading, pin 11 must be raised sufficiently to engage sleeve 27. When handle 40 reaches the bottom of slot 50 a lug 52 on collar 18, and which normally lies opposite a flange 39, is now positioned above the latter and handle 40 can be moved into the horizontal slot 51 to turn bar 20 anti-clockwise. A threading finger 21, secured by a screw 23 between guide fingers 22 which are in turn secured by a screw 24 to the lower end of bar 20, is thereby passed through the eye 6 of the needle. Thread T is then brought from a guide 12 on the needle clamp 9, is passed around a groove 25 in the projecting end of screw 24 and is laid over the hooked end of finger 21. Handle 40 is then moved clockwise to draw the thread through the needle eye. If the needle bar is positioned farther than 4À76 mm. from its topmost position, lug 52 will be disposed opposite flange 39 to prevent turning of bar 20. Alternatively, the needle bar cannot be operated when bar 20 is turned, since lug 52 is then disposed above flange 39.