GB825506A - Multi-needle sewing machine with means for selective engagement of the needle bars with the drive - Google Patents

Abstract

825,506. Sewing machines. DURKOPPWERKE A. G. Aug. 23, 1956 [Aug. 25, 1955], No. 25731/56. Class 112 In a multi-needle sewing machine the needle bars are reciprocated by a crosshead, coupling means operating between one or more of the needle bars and the crosshead are located within the respective needle bar which latter also has an uncoupling member within, and said member extends from the top of the needle bar for selective operation by obstruction, whereby one or more of the needle bars may be coupled or uncoupled to and from the drive selectively. Tubular needle bars 3, 4 are driven by a crosshead 6. Each needle bar contains a conical member 32 connected by an upwardly projecting stem 41 to a sleeve 42. A rod 39 has its lower end seated in sleeve 42 and its upper end projecting through a screw plug 40 at the top of the needle bar. A compression spring 43 is interposed between sleeve 42 and a collar 39<SP>1</SP> on rod 39. A compression spring 36, positioned at the bottom of the needle bar, exerts upward force on bar 39 via a head 37 and a stem 45 extending downwardly from the latter, a block being interposed between spring 36 and stem 45, and a compression spring 35 being interposed between head 37 and a conical member slidable on stem 45. The arrangement is such that member 32, under the influence of spring 36, normally urges three balls 31 radially outwards through holes in the needle bar to engage a conical seating 34 at the bottom of crosshead 6 to lock the needle bar thereto. Slidably mounted on a horizontal pin 9 is a block 10 having a depending finger 10<SP>1</SP> which may be moved over either of the needle bars, whereby, when the selected one of the latter rises to its topmost position, rod 39 is moved downwards to displace member 32 for freeing the balls 31, and member 46 displaces balls 44 outwardly into engagement with a conical seat 48<SP>1</SP> in the machine frame to lock the disconnected presser bar to the latter. The arrangement is also such that member 46 rises on stem 45 to compress spring 35 and to raise the needle bar slightly higher than its normal top dead centre position. Sleeve 10 is moved by a finger carried by a boss 11 fixed by a screw 13 to a rod 12 biased to a middle position by a pair of opposed springs 20, 21. Rod 12 and the springs are mounted in a housing 19 which is pivoted to the machine head and is connected by a link 30 to a lever 17, 14 pivoted at 15 on the machine frame. Arm 14 is formed with a slot 56 embracing the shank of a headed stud 59 attached to a leaf spring 57 adapted to engage behind a pin 60 on arm 14, for holding the latter at either one of its two end positions. Pressure on head 59 releases the spring, whereupon casing 19 is returned to the neutral position by means of another pair of opposed springs mounted within.