GB1426761A - Sewing machine - Google Patents

Abstract

1426761 Sewing machines G TOLLE 23 Feb 1973 [6 May 1972] 8913/73 Heading D1G In a sewing machine having the needle below the work and the loop taker on a pivoting bracket arm above the work, the needle bar 12 is reciprocated by a crank, and is embraced in a needle-bar gate 20 which pivots about an axis A. Pivoted on a projection 50 of the gate is a linked bracket 52 and flat leaf spring 57, linked to another flat leaf spring 73 through a universal joint 60 (Fig. 5). The second leaf spring is fixed to two identical arms 76 and the three together form a bell crank lever. A drive link 90 is driven by a crank pin 44 (Fig. 4) and being fixed to the bell crank lever, rocks the universal joint along a curved path D (Fig. 4). Because the leaf spring 57 is attached to the gate which pivots about the axis A (see Fig 3) the universal joint also follows the curved path B (Fig. 3) and so causes the gate to oscillate about its axis A. The two leaf springs 57 and 73 flex only in the plane XX to permit this motion. By adjusting the position at which the drive 90 is attached to the bell crank arms 76 the amplitude of oscillation of the gate may be adjusted, and by adjusting the screws 53 and 55 on the gate the position of the gate may be adjusted without altering the amplitude of its oscillation.