Abstract: A device to form the selvedge in shuttleless looms, includes a weft yarn gripping member, a first shaft reciprocable lengthwise to operate the weft yarn gripping member, a first linear electric motor to reciprocate the first shaft, a cutting member for cutting weft yarn gripped by the gripping member, a second shaft reciprocable lengthwise to actuate the cutting member, and a second linear electric motor for reciprocating the second shaft. A yarn engaging hook is carried by a needle to insert weft tails cut off by the cutting member, into a strip of warp yarns, thereby to form a selvedge. A third shaft carries the needle, from which said needle extends transversely. A third linear electric motor reciprocates the third shaft lengthwise. A sensor senses the reciprocated position of the third shaft thereby to control the third linear electric motor. A fourth linear electric motor rotates the third shaft.
Abstract: In a system for automatically controlling the tension of weft yarns fed to a loom with continuous weft feed, the extent of braking of the weft yarn is controlled based on signals output from a device for measuring weft yarn tension. Specifically, signals from a weft yarn tension measuring device are output to an electronic interface unit, which processes those signals and directs an actuator to brake the weft yarn more heavily when the detected tension is below a predetermined level, and less heavily when the detected tension is above a predetermined level.
Abstract: In a heald frame for weaving looms, wherein the two heald slide bars consist of standard elongated sections, the lower heald slide bar is formed of an elongated section of width smaller than that of the elongated section forming the upper heald slide bar.
Abstract: A strap controlling the motion of weft yarn grippers in shuttleless looms, allowing to detect its state of wear, is provided with layers or inserts distributed according to the thickness and positioned along the length of the strap, adapted to supply optic, electric or magnetic signals indicating the wear of the strap.
Abstract: A guide for the motion of a pair of weft grippers inside the shed of a shuttleless loom, in which two control straps each carrying one of the grippers move on a substantially horizontal plane under the action of two gearwheels with reciprocating motion. A plurality of elements guide the straps in this motion, these guide elements being aligned on a sley facing a reed of the loom and positioned perpendicularly thereto, the straps having a substantially rectangular section of greater width than thickness and a shaped recess extending along each longitudinal side edge. The guide elements are substantially horizontal tooth projection, shaped like and engaged in those recesses. The projections are wedge-shaped, the apices of the wedges being substantially half way along the thickness of the straps. The straps are wider and thicker adjacent the grippers than remote from the grippers.
Abstract: A guide for the to-and-fro motion of a pair of weft carrying grippers inside the shed of weaving looms with continuous weft feed, of the type comprising two control straps movable in a substantially horizontal plane thanks to the action of two gearwheels with reciprocating motion, and a plurality of guide elements for the straps, aligned on the sley facing the reed and positioned perpendicularly thereto. The strps have at least one undercut groove and the guide elements are open and form pairs of bilateral guides for the straps, of which they engage the undercut groove. The guide elements are suitably hook elements, open towards the reed, and the straps project out of these elements towards the reed, the pairs of bilateral guides each operating according to at least two orthogonal planes.
Abstract: Improved structure for guiding the weft-carrying grippers and their control straps through the shed of gripper looms comprises a single plurality of guide elements (3) aligned on the sley (1), each element (3) being provided with at least two distinct seats (4, 5) for housing respectively the strap (6) and the gripper (8), the seat (5) housing the gripper (8) being apt to prevent--either by itself or in cooperation with the seat (4) for the strap (6)--any lateral or upward movements of said gripper (8).
Abstract: A pair of weft grippers for moving weft yarn through a shuttleless weaving loom, comprises a carrying gripper for carrying the weft partway into the sheds of the loom and a drawing gripper for thereafter receiving and completing the passage of the yarn through the sheds. Each gripper has a body of solid synthetic resin faced on opposite sides with sheet steel that is partially embedded in the resin by molding. The spaced-apart steels shells impart great rigidity and wear resistance to the body, at the same time that the plastic body between the shells achieves light weight and low cost of the gripper.
Abstract: A weft carrying gripper for a weaving loom comprises a gripper body and a weft yarn holding member carried by the gripper body and oscillable relative to the gripper body about an axis parallel to the direction of movement of the gripper alternately to grip and release a weft yarn between a head on the holding member and the body. The head includes a resilient metal lamina secured to the head only at its rear end and extending forwardly to a free forward end. The lamina between its rear end and its free forward end has a straight portion that terminates forwardly in the free end. The free end curves from the forward end of the straight portion away from the body. The head has a recess behind the straight portion and the free end such that, when the holding member has oscillated toward the body, the straight portion lies flat against the body and the straight portion and the free end are free to flex away from the body under the pressure of a weft yarn inserted between the lamina and the body.
Abstract: Unwinding device for twin warp beams, with two separate unwinders, wherein the adjustment of the two unwinders (3, 4) is carried out according to the inclinations, detected by sensors (23, 24), which the two yarn carriers (5, 6) of the beams (1, 2) take up under the different tensions of the warp yarns (f).
Abstract: A composite gearwheel structure for reciprocating the gripper-carrying straps in weaving looms, comprises a gearwheel body of synthetic plastic material. Its teeth are partially covered with sheet metal associated with the body and forming an integral part thereof.
Abstract: A pair of weft carrying grippers, of the type wherein the weft yarn is retained by engagement of the head of a slider moving lengthwise, with a counteracting cooperating surface of the gripper body, the slider being thrust forward by a spring and being released by pulling a flexible lamina element connected thereto. In this pair of grippers, the flexible lamina element causing the release of the slider is controlled by a rotary cam having a slightly curved contour, around which the element may wind smoothly. Moreover, the slider head is shaped like a helical wedge, adapted to mate with an equally shaped counteracting surface of the gripper body, or it may carry at least one spring lamina, adapted to engage with a substantially flat counteracting surface of the gripper body.
Abstract: A guide for the gripper carrying straps inside the shed of weaving looms is formed as a nonsymmetrically shaped plate, the upper side of which is broken off to form two lateral slanting beaks delimiting the seat for the strap, the beak close to the reed being higher than the other. The seat has equal opposed ends of semicircular or wedge shape and a central undercut area on its side opposite to the beaks.
Abstract: A weft-carrying gripper for a weaving loom comprises a gripper body and a weft yarn holding member carried by the gripper body. The holding member oscillates relative to the gripper body toward and away from a weft yarn gripping portion of the body, alternately to grip and to release a weft yarn between a head on the holding member and the mentioned portion of the body. This oscillation can be either rectilinear movement of curvilinear movement. A flexible elastic element such as a spring metal lamina is carried by the head and is move toward and away from the yarn gripping portion of the body upon oscillation of the holding member. The elastic element, at the time it engages a weft yarn, bends about an axis transverse to the direction in which the head is moving at the time the elastic element engages the yarn.
Abstract: In a mechanism to control the movements of the weft carrying grippers in shuttleless weaving looms--of the type wherein a gearwheel controlling the grippers carrying strap is caused to rotate forward and backward by a variable pitch cam screw, passing longitudinally through a slider which moves forward and backward along a forced rectilinear path--the slider carries structure engaging the threading of said screw and adapted to cause the rotation thereof, comprising opposed pairs of oscillating sliding blocks.
Abstract: A carrying gripper for shuttleless looms, of the type comprising an elongated base member with a profiled front end, in which the weft retention element is constituted by a metal pointed head pivoted on an axis parallel to said base member and arranged to engage said member under the action of a spring in order to clamp the weft yarn against it. The spring acts on an arm secured to the pointed head, on the side of that axis opposite to that on which the engagement between the head and the base member takes place, namely on the same side from which the weft yarn is fed.