GB861730A - Improvements in or relating to sewing machines - Google Patents

Abstract

861,730. Sewing machines. PFAFF A. G., G. M. Nov. 6, 1958 [Nov. 11, 1957], No. 35628/58. Class 112 In a sewing machine rotary hook in which a raceway for a bearing rib on the bobbin case is provided by a gap between a shoulder in the hook body and a ring which is secured to the latter and is movable in the direction of the axis of the body, the ring is U-shaped in cross-section and its outer limb is secured to the outer surface of the body, while its inner limb extends into the body, is spaced radially therefrom, and cooperates with said shoulder to provide said raceway. The rotary hook comprises a body 2 secured by screws 11 to the driving shaft 12. A dished, plate member 1 is secured by screws 8 to the back of body 2, and its circumferential flange 15 is spaced radially from the outer surface of the latter. The circumferential rim 23 of the body is embraced by a ring member 3 of U-shaped cross-section. The inner wall 24 of member 3 is spaced radially from body 2, and is also spaced axially from a shoulder 16 in the latter to provide a raceway for a circumferential rib 17 on the inner portion 4 of the bobbin casing. The outer wall 18 of member 3 engages the outer surface of body 2 and is formed with resilient tongues 19. A groove 20 in each of the latter engages a circumferential rib on flange 15 to hold member 3 in position. The resiliency of the tongues allows wall 24 to move outwardly to permit passage of the thread. Member 3 is formed with a thread guiding point 26 offset from the loopslizing beak 25. The base of point 26 forms an obtuse angle, as at 31, with the base of the ring for holding the upper thread loop. Member 3 is also formed with a thread guiding flange 27, the sloped trailing portion 29 of which ends at an angle of 183 degrees from the beak 25. A pin projects radially from body 2 through a notch 32 in wall 18 to prevent relative rotation between body 2 and member 3.