| 摘要 |
1,128,780. Sewing-machines. A. J. MIT CHELL CO. 16 Dec., 1965 [19 Jan, 1965], No. 53492/65. Heading D1G. In a sewing machine a feed for moving work between successive sewing operations, e.g. attaching buttons or fasteners, or sewing button-holes, comprises an intermittently rotated drum having at least one clamp for securing the leading edge of the material. In the preferred embodiment the drum 5 is mounted adjacent a sewing machine 1 and is provided with two pivoted clamps 7, 7a. The clamps are normally urged against clamp pads, but may be raised by fixed and movable cams 74, 73 respectively, engaging actuating mechanism 67-71. The work is guided to the drum by guides 8, 13 and tensioned by a pivoted weighted arm 15. The extent of successive rotation of the drum is determined by adjustable switch actuating cams arranged around the inside of the drum. In the rest position solenoid armature engages a slot in the rear face of the first cam. The edge of the material is placed below the clamp and a start button depressed. Cam 73 is thus withdrawn so that the clamp secures the edge of the material, and sewing of a button is commenced. As the sewing operation finishes the armature is withdrawn and the motor started. When the drum has rotated a sufficient amount the next cam is held by engagement with the armature, and the motor is stopped. A new sewing operation is commenced if a sensing arm 23 detects the previously sewn button. D.C. current is momentarily applied to the motor to briefly urge the drum hard against the armature to tension the work. Thereafter there is sufficient play of the stop in the cam to allow the button to be moved during the sewing operation. This sequence continues until the sewing cycle following engagement of the armature with the last cam has been completed. The drum is then rotated until the first cam is adjacent a further armature and a stop switch at the top of the frame. The end of the first workpiece is thrown manually over drop rail 10. A new workpiece is placed in position, and a new sequence commenced during which the cams are arrested by the upper armature. The leading edge of the first workpiece is released automatically during the second sequence so that the work drops over the drape arm 12. The machine may be operated to sew one button and move the drum one position before it stops. |
