GB792366A - Improvements in or relating to the temporary disconnection of reciprocating members in high-speed machines - Google Patents

Abstract

792,366. Sewing machines. VEB SPEZIALNAHMASCHINENWERKE LIMBACH, Dec. 31, 1954, No. 37817/54. Class 112 [Also in Group XXIV] Embroidery machines, controlling needledriving mechanism. A needle bar 2 in a multi-needle embroidery machine and a pivoted arm 15 are connected by linkage to a continuously rotating driving shaft 14, the arrangement being such that either the arm or the needle bar may be held stationary, when the drive serves respectively to reciprocate the needle bar or oscillate the arm, whereby the needle bar may be stopped without the creation of inertia forces. The needle bar is pivoted at 6 to one end of a link 7 the other end of which is pivoted at 8 both to a link 10 and to a connecting rod 11 pivoted at 12 to a crank disc 13 fired to shaft 14, link 10 being pivoted at 16 to arm 15 which is pivoted at 17 to the machine frame. When pivot 16 is held stationary, the needle bar is reciprocated through links 7 and 11, and link 10 oscillates about pivot 16. When the needle bar is held stationary, link 7 oscillates about pivot 6 and arm 15 also oscillates about pivot 17. Pivots 6 and 16 are respectively released and held simultaneously when crank 13 and connecting rod 11 are in the top dead centre position I. The crank and connecting rod pass through a bottom dead centre position II when pivot 16 is held, and through a bottom dead centre position III when pivot 6 is held. Means for holding and releasing pivots 6 and 16 comprise a lever 18 pivoted to the machine frame at 19 and provided with a pair of teeth 21 which are respectively and alternatively engagable with notches 22 provided in the needle bar and in an arm 23 fixed to arm 15 concentric with pivot 17. An arm 27, fixed to a shaft 28 journalled in the machine frame, serves to shift the respective teeth into engagement with either the needle bar or arm 23. If arm 27 is moved in a clockwise direction from the position shown past pivot 19. a spring 25 will bias the lower tooth 21 against arm 23, when said tooth will slide on the latter till the parts pass through dead centre position I, when said tooth will enter notch 22 in arm 23 to hold arm 15 stationary, and the upper tooth 21 with simulateously leave the notch 22 in the needle bar to free the latter for reciprocation. A corresponding change over will occur, to lock the needle bar and free arm 15, if arm 27 is returned to the upper position as shown. An arm 35 fixed to shaft 28 carries a pin 36 which is normally engaged in a hole 41 in a bar 37 supported by arms 38 pivoted at 39 to the machine frame, bar 37 being rocked by means controlled by Jacquard mechanism to release or stop the needle bar. Shaft 28 carries a handle 33 by which it may be displaced axially against spring beds to withdraw pin 36 from hole 41, and by which it may be turned to transfer a pin 34 on the handle from one end to the other of a slot 40, when pin 36 is subsequently automatically re-engaged with hole 41. Alternatively, pin 34 may be engaged in a hole outside slot 40 to disconnect pin 36 permanently from bar 37 to hold the needle bar in the stationary position free from control by the Jacquard mechanism. A thread take-up arm 44 is provided at its free end with a thread eye 47, is pivoted at its other end on the crank pin 12, and is pivoted intermediately to an arm 45 pivoted at 49 to the machine frame. The take-up thereby continues to operate whether the needle bar is reciprocating or stationary.