GB185711A - Buttonhole sewing machines - Google Patents

Abstract

185,711. Fairweather, W., (Singer Manufacturing Co.). April 21, 1921. Gearing for starting and stopping machinery; operating clutches.-In a sewing machine, the stitch-forming mechanism and the feeding and button-hole cutting mechanisms are driven respectively by concentric shafts 10, Fig. 4, adapted to be clutched to a belt-wheel 13 mounted loosely on the end of the shaft 10 bv clutch and brake devices of similar construction. The device in connection with the shaft 9 is illustrated in Figs. 9, 11, 12, 13, 14, and comprises a disc 18 fixed to the shaft and having seats 20, 21 for a brake band 24 clutch band 28, the brake band co-operating with the inner surface of a hollow boss 16 on the frame and the clutch band with the recessed belt wheel 13. The bands 24, 28 carry rollers 25, 29 adapted for engagement by studs 34, 35 projecting from a clutch lever 31 mounted on a stud passing through an opening 32 and situated in a slot between the seats 20, 21. The arm of the lever carrying the stud 35 has an extension 36 on which is a lug 37 carrying a spring 40 which presses against a block 39 secured in a cavity of the disc 18 and tends to force the stud 35 into engagement with the clutch band roller 29 and withdraw the stud 34 from the brake roller 25. The extension 36 has a projection 41 which passes through clearances in the clutch band seat and the clutch band bears against the inner surface of the driving pulley restraining the movement of the clutch lever under the impulse of the spring 40 until the projection registers with a clearance notch 47 through which it emerges to-permit a clutching action which is converted into a positive coupling by the engagement of the projection 41 with a lug 44 on the rim of the wheel. The clutchlever also carries a projection 48 extending through slots in the brake and clutch bands and between the boss 16 and the driving wheel into position for engagement by a roller 57 carried by one of a pair of rock-levers 56, Fig. 9, respectively functioning for the shafts 9, 10. The levers are connected by links 61 to levers 64 fixed on inner and outer rock-shafts 65, 66, the extreme positions of which are determined by pairs of arms 70 provided with stop screws 73 which en page the boss 16 and determine the throw of the link 64. A spring 75 acts on an arm 70 to move the lever 64 so as to keep the roller 57 out of the path of the projection 48 the clutch lever then revolving with its driving wheel, but when the rock shaft is operated to move the roller into thepath of the projection the lever 31 is moved about its pivot and the wheel declutched and the shaft 9 or 10 positively stopped always in the same position, by the engagement of the roller 57 and' projection 48.