Patent GB-492720-A (GB)
Title: A new or improved means for spacing and forming button holes in articles of clothing
IPC: D05B35/12
Filed: 1937-03-24
Abstract: 492,720. Sewing-machines. JESSOP. G. March 24, 1937, No. 8633. [Class 112] An automatic sewing-machine for stitching buttonholes, attaching buttons, or forming other separate groups of stitches has combined with it means for automatically determining the spacing of a number of stitch-groups in a given overall distance and for automatically shifting the stitching devices relatively to the work after the formation of each group of stitches so that a complete series of separate groups may be formed automatically before the machine is stopped. The spacing device comprises a series of parallel gauge-bars 1 .. 6 sliding on rods 10 carried by a fixed bed 12, the bars 1 .. 6 being connected by lazy-tongs links 7 so that they are always equally spaced and parallel; two of the bars 2, 6, are extended and provided with clamps 17, 18 to hold the work 19, shown as a waistcoat requiring buttonhole stitchings. A rod 23 attached to the bar 6 carries adjustable stops 24, which limit the spacing of the gauge-bars by engaging a lug on the bar 5, and is engaged by a clamp 25 on the bar 2. Each gauge-bar has a pair of lugs 30, 31 for engagement respectively with a pawl 32 pivoted on the bed 12 and an auxiliary pawl 33 pivoted on the pawl 32 ; the pawl 32 has attached to it a rod 35 provided with stops for engagement by a lug on the machine head 11. In operation, one end of the work is held in the clamp 18 with the gauge-bar 6 in line with the desired position of the first buttonhole, the bars are moved apart or towards one another until the required bar (bar 2 in the case shown, for five buttonholes) is opposite the desired position for the last buttonhole, and the clamp 17 is closed on the work by means of a lever 27 which simultaneously actuates the clamp 25 to hold the bars at their proper spacing. The assembly is then moved along the rods 10 until the bar 6 is held by the pawl 33 in line with the machine head 11 and the starting lever 29 is depressed. As the stitching proceeds, the head 11 travels to the left, tripping the pawl 33 but first bringing the pawl 32 into the holding position, and then returns, tripping the pawl 32 to allow the assembly to be moved bodily by a spring 28 until the bar 5 is stopped by the pawl 33 in position for the sewing of the second buttonhole. The starting lever 29 is held down, so that the operation of the machine. is continuous, by a spring catch engaging a rod 36 fixed to the gauge-bar 2 ; the rod 36 is cranked at 37 so that at some time during the movement of the work to the last stitching position the catch moves clear of the rod and allows the lever 29 to return to the inoperative position so. that the machine is stopped after forming the last stitch-group. Instead of the machine head 11 being moved in stitching the buttonhole, means may be provided for imparting corresponding movements to the work. The clamp 17 may be separate from the bar 2 and adapted to be attached to any of the gaugebars according to the number of buttonholes required. The Provisional Specification describes a modified form of the detent mechanism, dispensing with the pawls 32, 33, in which one of the rods 10 is rotated by means of the rod 35 and has a transverse pin acting as a stop for the gauge-bars, the eyes on the gauge-bars engaging the rod 10 being so formed that the pin can pass through them in one position of the rod, but not in others. A dashpot or other device may be provided to produce a time interval between successive stitching operations to allow for the shifting of the work. The Provisional Specification also describes a modified form of gauging device, comprising a fixed bar having a series of collars slibable on it and a movable bar pivoted to the fixed bar and having telescopic gauge fingers attached to it at equal intervals, the fingers being free to slide through the collars on the fixed bar and having means for maintaining them parallel. It also states that the device may be used simply as a gauge for marking work, without automatic work-shifting means.