Patent GB-670830-A (GB)
Title: Improvements in or relating to overedge sewing machines
IPC: D05B73/04
Filed: 1949-12-01
Abstract: 670,830. Sewing-machines. UNION SPECIAL MACHINE CO. Dec. 1, 1949 [Jan. 24, 1949], No. 30845/49. Class 112. Frames.-The frame of an overedge sewing- machine is formed in two parts, upper and lower, which together form an enclosed chamber, the work support being carried by the lower part. The two parts meet on a horizontal plane below the level of the work support, and two alternative upper parts are provided, one equipped with a straight needle and the other with a curved needle, so that a machine of either form is readily obtained; the mechanism in the base portion is the same for each form of upper part, except for addition or removal of a few parts, so that production of the two forms of machine is economical: The base unit is shown at 91 in Fig. 9 and the upper part, carrying a straight needle 110, at 92, the two parts meeting on a plane 93 below the level of the work support 20 carried by the base portion 91, the head of the upper part, with the needle-bar and presser-bar 114, being inclined slightly for-' wardly; the upper part contains a needle-bar shaft 98 and an intermediate shaft 135 carrying an idle pinion 134 through which the shaft 98 is geared to the lower main shaft 137. In Fig. 1 the same base unit carries an upper part 12 provided with a rock-shaft 32 having an arm 35 to which is clamped a curved needle 36; a large opening in the top of the part 12 is closed by a cover 15. In each form the upper part 92 or 12 forms a mechanism-enclosing chamber with the main part of the base portion 91 which is closed by a bottom plate 90 and contains lubricant; part of the mechanism lies in a separate compartment under the work support, with a cover at the side. The arrangement of the work support and the means for distributing lubricant are as described in Specification 668,896. Driving.-The driving pulley 99, in the machine shown in Fig. 9, may be fixed on either the upper or the lower shaft. Stitch - forming. - The needle-bar in the machine shown in Fig. 9 is inclined slightly forwardly for better cooperation with the usual loopers. In the machine shown in Fig. 1 the gear 136 is omitted from the lower shaft 137, the driving pulley is carried by this shaft, and a pitman 30, additional to those used in the straight-needle machine, is provided to actuate an arm on the needle rock-shaft 32 from an eccentric portion of the shaft 137. The looper mechanism in both machines is the same as that described in Specification 668,896. Presser-bars; presser-feet.-The presser-bar 114 in Fig. 9 is inclined, parallel to the needlebar, and slides in notches in the ends of the walls of the machine head and is held therein bv the cover 97; it is pressed downwards by a spring, and can be lifted by a spring-loaded arm on a treadle-operated rock-shaft arranged parallel to the shaft 98 outside the frame. The presser-foot, Fig. 8 (not shown), is connected by a leaf spring to a forward extension of the lower end of the presser-bar, and rocks on a knifeedge on the underside of that extension. The work is fed by main and auxiliary feed dogs as described in Specification 668,896, and is trimmed by mechanism as described in that Specification.