GB736277A - Improvements in or relating to sewing machines - Google Patents

Abstract

736,277. Cams. SOC. ANON. A. VIGORELLI. Nov. 30, 1953 [Jan. 28, 1953], No. 33158/53. Class 80 (3). [Also in Group VII] A zig-zag sewing-machine has a plurality of cams, each adapted to produce a different stitching pattern, the needle-vibrating mechanism being connected to a single cam-follower contact element which can be brought into position for actuation by any one of the cams. The cam-actuated means may be positioned for simultaneous engagement with any two adjacent cams, so that it is controlled by whichever of these cams is higher at any instant. The cams are removable as a unit, and are preferably separate so that they may be exchanged for others, or rearranged in the unit to provide for different combinations. Means are provided for variation of the amplitude of needle vibration and for suppressing the vibration, and for lateral adjustment of the mid-position of the needle. In the mechanism shown in Fig. 1, the needle-bar guide 12 is pivoted at 13 and has a pin 30 engaged by a forked lever 28 pivoted at 29; a member 26 connects this lever to a pin 25 slidable in a guide 72, Fig. 6, by means of a camactuated lever 21 pivoted at 23 and connected to the member 26 by a link 24, the cam-follower 20 on the lever 21 being pressed against the cam 16 by a spring attached to the member 26, as shown in Fig. 1. One of the cams 16 is formed by an end flange on a sleeve which is carried non-rotatably on a shaft 17 driven through reduction gearing from the main shaft 15 and is secured by a nut; the remaining cams (five in the machine described) are fitted non-rotatably on the hub of the sleeve and secured by a nut thereon in the form of a disc closing the aperture in the frame through which the cam unit or individual cams may be withdrawn. The cam follower 20 is carried by a cylindrical member 51, Fig. 6, slidable in a transverse guide in the end of the lever 21, and is shifted to engage the required cam, or pair of cams, by a lever 55, Fig. 1, pivotally connected to the member 51 and adjustable by engagement with a helical groove in a finger-rotatable spindle; the spindle is held in the desired position by a spring ballcatch under its finger-knob, which bears indicating marks to show which cam is effective. A push-button 65, Fig. 1, is provided to engage the lever 21 to raise the follower clear of all the cams during its lateral adjustment or for withdrawal of the cams. The inclination of the guide 72 is varied, to adjust the amplitude of vibration of the needle, by a finger-lever 75, with an arm 82 working between adjustable stops 83, and the guide is mounted in a lever 77, pivoted at 86, so that it can be shifted bodily laterally, to alter the position of the mid-point of the needle vibration, by an eccentric pin 88 on the spindle of a finger-lever 90; the pin 88 also shifts a face-plate 79 embracing the spindle of the guide 72 and lever 75 and carrying the stops 83 and graduations for indicating the amplitude for which the guide is set.