GB690334A - Improvements in or relating to sewing machines - Google Patents

Abstract

690,334. Sewing-machines. KOSTRO, W., and JOZWIAK, S. Jan. 18, 1951 [Oct. 18, 1949], No. 26734/49. Class 112. A machine designed for blind-stitching abutting edges or superposed layers of material comprises an oscillating part-circular hollow needle, through which a thread passes, and a member receiving a second thread and oscillating in a plane perpendicular to that of the needle. In the forms described, the machine is fed over the work, and the member with the second thread is adapted to form a lock-stitch. Blind-stitching and like machines.-The machine shown in Fig. 1 has a base 7 adapted to slide easily over the work and formed with an aperture for access of the needle to the work. A shuttle 3 oscillates in a hole in the base 7 and is driven from a gear 19 oscillated by a connecting-rod 52 from a crank-disc on the main shaft 37, the rod 52 having a pin-and-slot connection with the gear 19 to give a dwell at each end of the shuttle movement. The needle is carried by a shaft mounted parallel to the length of the base in a housing 4 and geared to a wheel 29 which is oscillated by a link 31 actuated by a cam 32 bevel-geared to the main shaft 37; the cam causes the needle to pause while the shuttle engages its thread and while the stitch is set. The housing 4 has a depending feeler member to engage between abutting edges of pieces of carpet to guide the machine so that the needle enters one piece and emerges from the upper surface of the other to present its thread to the shuttle 3. The needle and shuttle are described below. The needle thread passes from a spool 23 to the needle by way of a tension device 51 carried on a take-up arm which is oscillated by a linkage 49 from a cam on the shaft 37. The machine is propelled over the work by wheels 58, as described below. In a modification, Fig. 15 (not shown), for connecting superposed layers of work by a seam which lies wholly in the line of feed, the needle is carried by a housing which projects forwardly from the base 7 and which has a presser member resting on the work and providing for adjustment of the depth of penetration of the needle into the work; the needle is oscillated in a vertical plane parallel to the line of feed by a linkage from a cam on the vertical main shaft. The mechanism actuating the various moving parts is modified and differently arranged. The main shaft may be driven by a motor above it and clutched to it, or by worm gear from a horizontal shaft belt-driven by a motor, or by a hand wheel; alternatively a spring-returned vertically-moving hand lever may actuate the various parts through rack or other gearing. Needles.-The hollow needle 20, Fig. 16, has a sharpened, obliquely-cut end with an eye 25 through which the thread emerges so that it forms a chord from the point of emergence of the needle from the work to enable the shuttle beak to enter between it and the needle. Seams.-When the needle plane is parallel to the line of feed the seam is as shown in Fig. 16 (the boundary between the layers of the work being omitted for clarity), with the two threads superposed on the surface of the work, the needle loop being indicated at 22 and the shuttle thread at 43; when the needle is transverse to the feed line, the two threads lie parallel, one on each of the abutting work-pieces, Fig. 9 (not shown). Shuttles.-The shuttle, Fig. 4, comprises two dished members 5, with flanges 5a, which have central interengaging portions forming a spindle for the bobbin and are spaced apart by a rib 8a on a thin cylindrical member 8b which forms a circumferential wall for the bobbin; the member 8b is held more or less stationary, while the members 5 are oscillated by gears engaging with an arcuate rack 18 fixed to the inside of the flange 5a of one of them. The members 5 are held together by a central headed pin 9, which has a transverse locking pin 11 to secure it after being passed through a slot 12 in one of the members, and are pressed apart by a spring surrounding the pin 9; the flanges 5a lie respectively above and below a ledge in a hole in the base 7 of the machine, and are cut away as shown to form twin thread-engaging beaks 40. The bobbin thread passes out through a slot extending to one edge of the member 8b, under a tensioning spring 16 secured to that member, and through a tube 15 rigid with the rib 8a. Feed by moving machines; feed by wheels.- The machine shown in Fig. 1 is moved over the work by wheels 58, with milled or other suitable peripheries, on a shaft 60 which is driven stepby-step through a one-way drive 61 by a lever 62 engaging a face cam on the main shaft 37. In a modified form,'Fig. 15 (not shown), a single wheel 58 is placed in the middle of the base. Instead of the machine moving, the work may be fed under the machine.