| 摘要 |
The drive assembly for a form feeding tractor has a flexible endless belt comprising an endless band member of synthetic resin with a generrally planar outer surface and metallic drive pins spaced about its circumference. The band member has a series of spaced apart drive sections each with a plurality of drive teeth extending transversely thereof on its inner surface, and the metallic drive pins are disposed in the spaces between the drive sections. The pins have a base section which extends through the band member with a circumferential groove intermediate its length and into which the band member extends, and the band member has platform portions on its inner surface which extend about the base portions on the pins. The cooperating drive sprocket has in its circumference a series of spaced apart drive sections with transversely extending drive grooves configured and dimensioned to mesh with the drive teeth of the belt, and transversely extending recesses in its circumference in the spaces between the drive sections. The platform portions of the belt are received in the recesses which are of greater width than the platform portions to preclude engagement with the side faces of the platform portions.
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