GB1025858A - Chain stitch device for lock stitch sewing machines - Google Patents

Abstract

1,025,858. Sewing machines. SINGER CO. Feb. 15, 1965 [Feb. 24, 1964], No. 6436/65. Heading D1G. A lock stitch sewing machine comprising a rotary looptaker disposed beneath a work support and journalling a stationary bobbin holder, is converted to chain stitching by the provision of an upwardly-projecting member biased upwardly towards the work support and thereby so positioned above the bottom surface of a threadguiding member provided on the work support as to retain a cast-off loop of thread, and means for lowering the top of the thread-retaining member below the bottom surface of the thread-guiding member to permit a first trapped loop to be pulled off the thread-retaining member by the thread take-up mechanism after a second loop has been passed through the first loop by the endwise reciprocation of the needle. The bobbin normally supported in a bobbin holder 34 journalled in a rotary hook 32, is replaced by a cylindrical member 70 formed in its upper surface with a groove 73, in which is pivoted at 74 a finger 71 carrying at one end an upstanding lug 72. A modified throat plate 52 is provided having an elongated needle-passing slot 81, and formed adjacent the latter with a downwardlyprojecting lip 80. A spring disposed between finger 71 and the base of slot 73 biases lug 72 upwards against the under surface of the throat plate closely adjacent lip 80. An initial loop 90 cast off the looptaker beak 33 is thereby retained on lug 72 until the needle descends therethrough and beak 33 draws a succeeding loop 93 through the trapped loop 90. The feed dog 49 then descends and a web 50 rigid therewith engages finger 71 to depress lug 72 below lip 80 for releasing loop 90, whereby the latter is set into the work by the action of the normal take-up means.