| 摘要 |
<p>The system provides for the feed (P1) and leather-locking (P2) feet of a machine (100) with dual needle tip feed to be respectively actuated with first and second means (M1, M2), independent of each other, placed in phase relation with the movements of needle (A). The first gears (M1), actuated by the drive shaft (B) of the machine (100), are of the mixed type, mechanical or pneumatic, and are suitable for defining two working heights (W1, W2) for said feed foot (P1), respectively provided for a minimum and maximum thickness of the material to be sewn, with said working heights being adjustable so that when foot (Pi) is at the phase bottom dead centre thereof, it slightly touches the material surface without pressing it, so as to not hinder the feeding of the latter. Said working heights (W1, W2) can be switched from the one to the other and Ace versa by the operator, while sewing. The second means (M2) are of the pneumatic type and are controlled by means for phase actuation associated to The drive shaft (B) of machine (100). The proposed system, as compared to known mechanisms, makes the material feeding easier, prevents damages thereto by the feed foot (P1) and allows the working height of the latter to be changed according to the thickness of the material met.</p> |
