Patent GB-679949-A (GB)
Title: Improvements in lockstitch sewing machines
IPC: D05B51/00
Filed: 1950-06-15
Abstract: 679,949. Sewing-machines. UNION SPECIAL MACHINE CO. June 15, 1950 [June 22, 1949], No. 14917/50. Class 112. Rotary take-ups.-A thread-engaging element projecting laterally from a rotating disc is grooved to receive a part projecting from a fixed cover, the latter part serving to guide the thread and to engage and remove broken thread which becomes wound on the element; means are preferably provided to cut such thread. The cover and the disc have closely approaching central parts to provide a narrow thread-confining passage. In the embodiment described the edge of the disc is cam-shaped and engages the thread to give additional take-up effect. In the form shown, the thread-engaging element 61, Figs. 2 and 9, is fixed to a cam-shaped disc 60 mounted on a shaft 56 placed above and slightly in front of the needle-bar shaft and driven therefrom by equal gears near the right-hand end. The righthand side of the take-up is covered by a circular plate 70 fixed to the machine head and provided with a flange 69; a member 76 fixed to the lower part of the head and projecting through a gap in the flange 69 carries an outer cover 75, the remainder of the outer side of the take-up being substantially covered by a member 101 fixed to lugs on the flange 69 and a part 107 fixed by a flange to the side of the cover 75, a gap 69a between these two members providing for passage of the thread across the edge of the take-up cam disc 60. A plate 84 fixed to the inside of the cover 75 has a thread-guiding flange 85, Fig. 25 (view from in front and below), which is received in an arcuate groove in the take-up element 61, the flange being formed with a slot 90 to constrain the thread passing from a guide 72 (Fig. 2) to the element 61 and with a shoulder and inclined slot 87 to engage any thread wound on the element 61 and carry it off the end of that element; to assist in removal of such thread the element 61 is tapered from the base for part of its height, and this taper is continued to the top on one end face adjacent to the groove. A thread-cutting blade (not shown) is fixed to the cover 75 so as to lie flat against the member 84 close to the inner end of the slot 87 to cut the thread when it is forced into the slot; an aperture in the member 84 facilitates removal of the cut thread from the element 61. To eliminate whipping of the thread as far as possible frusto-conical members 110, 111, Fig. 9, are provided on the cover 75 and disc 60 respectively leaving a narrow thread space between them, a finger 106, Fig. 2, continuing the flange 69, overlies the thread passing to the needle, and a guiding hook 104 formed on the end of the member 101 also constrains this limb of the thread; the end of this hook is received in a recess in the cover 75. The parts are arranged so that the thread can be passed into position between them without requiring threading through any aperture. In a modification the members 75, 84 and 110 are combined into a single member. Lubricating.-The lower part of the machine standard forms a lubricant reservoir into which the belt and pulley driving the lower shaft dip to create an oil mist within the standard and the upper arm; some of this mist is taken by a wick-filled tube to various parts in the head of the machine, and lubricant dripping down the standard is received by a member arranged to deliver it into an axial bore in the lower shaft. Gears driving the rotary hook shaft from the main lower shaft are enclosed in a separate oil chamber, and the hook race is lubricated from a separate reservoir feeding an axial bore in the hook shaft which contains a helical oil-feeding member or a grooved rod fitting in the bore and reduced at its right-hand end to provide clearance in a reduced part of the bore. Feed, regulating.-The control shaft of feedregulating mechanism similar to that described in Specification 413,120 has at its right-hand end an upstanding arm by means of which it may be angularly adjusted, against the action of a biassing spring, by a screw-threaded pushrod with a finger knob 53, Fig. 2.