Patent GB-1061682-A (GB)
Title: Automatic device applied to a sewing machine to feed the fabric
IPC: D05B35/12
Filed: 1965-03-29
Abstract: 1,061,682. Spring drums. NECCHI S.p.A. March 29, 1965 [April 10, 1964], No. 13151/65. Heading B8B. [Also in Division D1] In sewing apparatus a workpiece is releasably clamped between a front carriage movable on vertical guides and a counterweighted rear carriage movable on horizontal guides, the carriages being interconnected by a cable equal in length to the workpiece. A sewing machine operates on the workpiece when the front carriage is automatically stopped at predetermined intervals. At the end of the operating cycle, the workpiece is automatically released from the front carriage and the latter is returned to its initial position, while the rear carriage, mounting a spring drum on which said cable is wound, is held stationary and the drum is released for rotation. The rear carriage is slidably mounted on a horizontal rail 60, and is connected by a cable 64 to a counterweight. A cable 78, attached to the front carriage, passes through an eye 89 in a plate 90 fixed to carriage 14, and is wound in a helical groove in a drum 80 mounted on a screw-threaded portion of a shaft 83 rigid with carriage 14. The arrangement is thereby such that drum 80 on rotation moves axially to maintain cable 78 aligned with eye 89. A stressed torsion spring is fixed at its respective ends to shaft 83 and to a drum 92 journalled on the plain end of shaft 83, and a pin projects axially from drum 92 into sliding engagement with drum 80, whereby the latter is biased to take up the slack in cable 78. A plate 111, pivoted on a pin 108, is biased by an over-centre spring 117 to engage either one of shoulders 114, 115 on plate 111 with a pin 110 carried by a rearwardly-extending arm of a lever 109 pivoted on pin 108. When shoulder 114 engages pin 110, a vertical pin on a forwardly extending arm of lever 109 is biased against an angularly-adjustable ring 101 rigid with drum 80, and enters a radial hole in ring 101 when the length of cable 78 stretched between the carriages equals the length of the workpiece. During the operating cycle of the apparatus, drum 80 is thus locked to lever 109, and a shoulder 113 on plate 111 depends beside rail 60. Simultaneously with the end of the operating cycle, when the workpiece is automatically released from the front carriage and the latter first descends to its lowest position and then rises to and halts at its highest position, a fixed block positioned beside rail 60 is engaged by shoulder 113. Plate 111 thereby swings to engage shoulder 115 with pin 110 to uncouple lever 109 from drum 80, and to engage a shoulder 112 with said block to hold carriage 14 stationary. Drum 80 then rotates to pay out or wind in cable 78 in accordance with the movements of the front carriage. The workpiece is then released from the rear carriage, a fresh workpiece is inserted, and carriage 14 is drawn rearwardly by a handle 120, whereby said block co-operates with shoulder 112 to swing plate 111 for re-engaging shoulder 114 with pin 110. Carriage 14 is then drawn rearwardly by the counterweight until lever 109 is re-locked with drum 80.