| 摘要 |
A sewing machine for sewing and feeding material has a rotatable main shaft in a housing which is connected to drive a reciprocating needle for reciprocation in a stitching area. Adjacent the needle is a presser rod which depends from the housing and a carrier is mounted on the rod for upward and downward movement and is biassed downwardly so as to press a feed roller rotatably mounted on the carrier against the material to be fed. A drive mechanism for the feed roller is mounted on a bracket extending outwardly from the housing, and it includes a rotatable drive gear which is driven intermittently through an oscillation mechanism driven from the main shaft. A substantially triangular rocker member is pivotally mounted on the same axis as the drive wheel, and it supports two spaced apart guide rollers over which a drive belt is guided. The drive belt is connected to the gear drive wheel and to a gearwheel on the feed roller to rotate the feed roller intermittently. The construction includes a coupling rod connected between the carrier and the rocker which is adjustable in length. The gear belt, which is guided around the uppermost one of the guide rollers defines an engagement angle around the roller which has a bisector which intersects the longitudinal axis of the coupling rod in a substantially horizontal plane. The driving arrangement is such that the lifting force produced by the belt pull during the drive of the feed roller is substantially eliminated.
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