| 摘要 |
1. Sewing machine work feeding device including a pair of rolls behind the needle, which pair is operated by means of a crank gear (2, 7, 10) supported in a housing above the sewing machine and serving for the transformation of the rotation movement of an input drive axle (13) in a reciprocating movement of an output axle (11) for periodical advance of said pair of rolls, of which the crank (2) is provided with a crank pin (6) adjustable along the crank radius for an adjustment of the stroke of a connecting rod (7), the movement of which causes a swinging movement of the output shaft (11), the crank pin (6) being connected with the crank web (18) of a crank arm (4), which web is slideable in a guide flange (19) of a trunnion (20) rotatable supported in a housing (25) and lies against an axially movable stop (34, 37) for a variation of the crank radius by means of a pressure produced by a spring element (43), which stop is a displaceable adjusting bolt (34) protruding a guide flange (19) and the trunnion (20) in a central bore, against which the crank web (18) with in an inclined plane (36) made in a cavity (35) thereof lends, characterized in that the crank pin (6) is supported in a further crank arm (5), which is composed of a coupling flange (48) and a drive flange (45) coupled therewith through a displaceable guide means (49, 50), and that the stop in one of the crank arms (4) is a ball displaceable by means of the adjusting bolt (34), which is guided by a support member (44) resting in the guide flange (19) and extending into the cavity (35). |
