Abstract: A device (1) for execution of overcasting seams comprises two needles (3, 4) carrying respective sewing threads, two support arms (6, 9) on each of which two lower (7, 8) and upper (10, 11) loopers respectively, are mounted. The loopers of each support arm (6, 9) interact with the loopers of the other arm (6, 9) and with the needles (3, 4) to form a first and a second overcasting seam portions superposed on each other. The invention also relates to a method to be put into practice by such a device (1), a needle plate to be installed on such a device (1) and a seam consequently obtainable therewith.

Abstract: In a sewing machine with cylindrical base the transport claws are actuated by a device comprising a kinematic transmission mechanism which, through oscillating auxiliary shafts, is connected to a rotating main shaft housed in the foundation to transmit a vertical oscillatory motion to the claws, as well as a lever transmission mechanism which, through transmission levers pivoting according to vertical axes, is interconnected to an auxiliary transport shaft housed in the foundation to transmit a horizontal reciprocating motion to the claws. A reduction in the size of the base of the sewing machine is thus obtained, without thereby penalizing the structural resilience and the operating reliability of the device for the actuation of the transport claws.

Abstract: In a device for forming ornamental stitch seams, which comprises two or more needles (3a, 3b) moving alternately backward and forward through a needle plate (2) and a looper (5) cyclically movable following an elliptical trajectory (t) under the needle plate (2), the needles (3a, 3b) describe inclined trajectories (y) to form, with the needle plate (2), an acute angle turned towards the sewing direction (A), for crossing the looper trajectory (t) at a "crossing area" that, relative to a vertical direction (v) passing by the point at which the needles (3a, 3b) get through the needle plate (2), is shifted in a direction opposite to the sewing direction (A).

Abstract: In a two-needle sewing machine for making an ornamental stitch without a cover stitch, at least one intermediate lug (17) is provided which is disposed in side by side relation with respect to an upper thread take-up (13) engaged to the needle bar (7), said intermediate lug, in the absence of a workpiece (4) on the needle plate (8), is brought to a work position in which it interferes with one of the needle threads (4a, 4b) coming from an auxiliary thread take-up (12) being part of a feed unit for the needle threads. In the presence of the intermediate lug (17) in the work position, the orientation of the needle thread (4a) intercepted by said intermediate lug is suitably deviated with respect to the upper thread take-up (13), so as to cause a tension release on the needle thread itself during the raising steps of the needles (3a, 3) towards the upper dead center of their reciprocating motion.

Abstract: In a trimming sewing machine of the type adapted to carry out a two-thread overedge stitch, provision is made for a hooked element (15) integrally associated with the upper looper (10), which hooked element has an end work portion (15a) disposed in parallel side by side relation with the end work portion (10b) of the upper looper. The hooked element (15) engages the sewing thread (3) carried by the needle (2) at the beginning of the downward stroke of the needle. Following the downward stroke of the upper looper (10), the hooked element (15) drags along the sewing thread (3) beyond the lateral edge (5a) of the workpiece (5). Thus paired finishing portions (17a, 17b) are formed along the sewing thread (3) and they extend from each of the insertion points of the needle (2) into the workpiece (5) as far as close to the lateral edge (5a) of the workpiece (5).