Patent GB-1188925-A (GB)
Title: Needle Bar Throw Out Mechanism.
IPC: D05B81/00
Filed: 1969-01-14
Abstract: 1,188,925. Sewing machines. SINGER CO. 14 Jan., 1969 [19 Feb., 1968], No. 2037/69. Heading D1G. A sewing or tufting machine comprises separable interengaging means on the needle bar and the needle bar-reciprocating means respectively, a disengaging element shiftably supported on the needle bar and having an operative position for separating the interengaging means, means shiftably supported on the machine frame for movement into and out of effective position in the path of the disengaging element at a predetermined position of reciprocation of the needle bar to urge the disengaging element into operative position, friction brake means carried on the machine frames and engagable with the needle bar, and means responsive to movement of said shiftably-supported means for rendering the friction brake means effective. The needle bar 36 of a single-needle tufting machine is axially slidable in a fixed lower sleeve (40) and an upper sleeve 42 which is non-rotatable but is axially slidable and is formed with screw threads 100 engaged by a nut (128) for raising or lowering sleeve 42. A driving block 32 is slidable on needle bar 36 and is connected by a link 24 to a crank pin 26 carried by the arm shaft 20 of the machine. Block 32 is normally coupled to a latching block 132, rigid with needle bar 36, by the engagement of the lower hooked ends 158 of a pair of latch fingers 148, pivoted intermediately at 150 to block 132 and biased to latching position by a spring 160, with a circular flange 164 on the upper end of block 32. Latch fingers 148 are released from flange 164 by the engagement of the inwardly-curved upper ends 152 of fingers 148 with a conical recess 124 formed in the lower end of an unlatching block 116, slidable on sleeve 42, when block 116 is moved downwardly. The lower end of sleeve 42 is formed with axial slots 104 defining resilient tangs 105 which are formed at their lower ends with outwardlycurved lips 108. A collar 110 is supported on lips 108 within block 116. A compression spring 114 is interposed between collar 110 and the upper end of block 116. Nut (128) is initially adjusted for raising sleeve 42 sufficiently to stress spring 114. Block 116 is formed with opposed grooves engaged by the respective arms of a U-shaped bracket 93 pivoted on a pin 91 at one end of a lever 82 pivoted intermediately and connected at its other end by a linkage to a treadle or the like. Actuation of the latter thereby serves to shift block 116 downwardly to engage recess 124 with ends 152 for unlatching needle bar 36. Downward movement of block 116 also serves to compress spring 114 and thereby shift collar 110 downwardly to shift tangs 105 inwardly into frictional engagement with needle bar 36, whereby the latter is positively retained in its uppermost position when uncoupled from block 32. Actuation of said treadle is also arranged to raise the presser bar. The needle (38) co-operates with a looper (52) and knife (54) to produce a row of cut tufts. A yarn-control finger (99), rigid with the upper end of needle bar 36, projects laterally through a slot (98) formed in a portion of sleeve 42 extending above the machine frame.