Giver gripper for a gripper loom

Abstract: A giver gripper for a gripper loom has a cover (7), provided on that side closer to the loom reed with a guide and positioning groove (10) for the weft yarn and on the other side with a wall (15) extending downwards to form a deflector (16). The corner (7) is removably mounted on the gripper body (1).

Description: This invention relates to a giver gripper for a gripper loom which, in addition to being of high performance, is of extremely simple construction making it economical and advantageous, in that those elements most subject to wear are now formed as a single piece which is mounted on the gripper body in an easily removable manner. In a gripper loom the purpose of the giver gripper, mounted at one end of a transporter tape driven with reciprocating motion, is to grip a weft yarn external tc the shed formed by the warp yarns, drag said weft yarn into said open shed as far as the centre thereof, and return to its starting point in order to be able to grip a new weft yarn after yielding its own weft yarn to a taker gripper the purpose of which, also mounted at one end of a second transporter tape driven with reciprocating motion, is to complete the insertion of the weft yarn by dragging it out of the other end of the shed. It will be clear from the aforegoing that the operation of the grippers, and in particular the giver gripper, is of basic importance in the correct operation of a loom. In this respect, the giver gripper has to be able to grip the weft yarn in such a manner as to maintain it reliably clamped, but without altering the yarn properties, as far as the centre of the shed. It therefore requires suitable and appropriate weft yarn guide and gripping members which must also allow effective and reliable transfer of the yarn to the taker gripper. Moreover as the giver gripper is inserted into and slides within the shed formed by the warp yarns, it inevitable stresses said yarns and must therefore be shaped such that said stressing does not damage or indeed break the warp yarns. Finally, each giver gripper comprises parts which are inevitably subject to wear due to the continuous sliding of the weft yarn, which could create roughness dangerous for the yarn integrity, and consequently the gripper must be subjected to continuous inspection because the quality of the fabric formed depends on its perfect operation. It is therefore apparent that there is a continuous search for increasingly improved giver grippers to achieve increasingly better results. A large variety of giver grippers for gripper looms are already known in the state of the art examples of which are disclosed in US-A-3 934 621 and GB-A-2 018 307. The type currently most used is a one-piece giver gripper with a basic structure substantially of U-shape, with two vertical lateral points at the front, that closer to the reed being more forwardly projecting, said points being higher than the front tip of the horizontal cover which lies between the two vertical points. That vertical wall of the basic structure closer to the reed is provided with a guide and positioning groove for the weft yarn, a gripping member being arranged on the opposite side of the gripper longitudinal to said groove, a vertical deflector being provided between said guide groove and said gripping member to arrange the yarn with an inclination of not more than 45°, so as to facilitate the withdrawal of the yarn by the taker gripper. Such a giver gripper has proved to be of high performance, but has the drawback of not allowing economical and rapid servicing of its wearable parts. In this respect, as is well known to the expert of the art, the critical points of a giver gripper are the inner end of the guide and positioning groove for the weft yarn and the inclined front face of the deflector, in which the sliding of the weft yarn produces wear which can compromise the proper operation of the gripper and can create roughness dangerous for the weft yarn integrity. With known giver grippers of the state of the art, when gripper wear arises the entire gripper has to be replaced, with evident considerable economical loss. The present invention seeks to obviate said drawback by providing a giver gripper which is of simple construction and hence of low cost, and which allows rapid replacement of just the worn parts, with a consequent considerable reduction in the loom operating cost. According to the invention, there is provided a giver-gripper for a gripper loom, comprising a box-like gripper body of substantially U-shaped cross-section, with two vertical lateral points at its front, that closer to the reed being more forwardly projecting than the other, a substantially horizontal cover located between the two lateral walls of said gripper body, said cover having a front tip substantially between said two vertical points of the gripper body, said tip being at a height above the base of said gripper body which is slightly lower than that of said vertical points of the gripper body, a gripping member for the weft yarn positioned on said base on that side more distant from the reed, a guide and positioning groove for the weft yarn and a deflector for arranging the weft yarn inclined within the giver gripper, is characterised according to the present invention in that said cover is removably mounted on said gripper body between that vertical wall of said gripper body closer to the reed and said gripping member, and is provided with said guide and positioning groove for the weft yarn on that side closer to the reed, and with said deflector on the other side. Thus the said wearable parts of the giver gripper are formed as a single easily removable element of the gripper, generally its cover. In this manner, in the case of wear it is sufficient merely to replace the removable cover, and continue to use the same gripper body, with evident saving. The cover with said guide and positioning groove and said deflector may be mounted to be easily removable on said gripper body by screwing that wall thereof more distant from the reed, and extending downwards to form said deflector, to a wall of said gripper body which rises on that side of said gripping member closer to the reed, said cover comprising on that side closer to the reed a vertical wall provided at its lower end with a hole arranged to cooperate with a centering pin projecting from that outer surface of said wall of said gripper body closer to the reed. Finally, the guide and positioning groove for the weft yarn may extend within said cover approximately as far as the central longitudinal axis thereof, so as to arrange the weft yarn, in cooperation with said deflector and said gripping member, with an inclination greater than 45° to said base of said gripper body, and preferably with an inclination of about 60°. The invention will now be described in greater detail, by way of example, with reference to the drawings in which: Figure 1 is a perspective view of a giver gripper formed in accordance with the present invention, and Figure 2 is a perspective view of the giver gripper of Figure 1, with the removable cover detached from the gripper body. In the figures, the reference numeral 1 indicates the gripper body of a giver gripper for a gripper loom, formed in accordance with the invention. Said gripper body 1 consists substantially of a box body of U cross-section, the vertical lateral walls 2 and 3 of which terminate frontally in two vertical points, 2" and 4 respectively. The vertical point 2", which is that closer to the loom reed (not shown), projects more forward than the other point 4, the two vertical points 2" and 4 rising to a height slightly greater than the height, from the base 5 of the gripper body 1, of the horizontal tip 6 of the removable cover 7, which extends between said vertical points 2" and 4. To that vertical lateral wall 3 of said gripper body 1 further from said reed (not shown), there is hinged at 8 the gripping member 9 for the weft yarn. Said removable cover7,which is positioned between said gripping member 9 and said vertical wall 2, is provided on that side in correspondence with said wall 2 and hence on that edge 7' closer to said reed (not shown), with a weft yarn guide and positioning groove 10 which extends from said edge 7' nearly as far as the central longitudinal axis 11 of the cover 7, and with a vertical wall 12. Said vertical wall 12 comprises at its lower end a hole 13 (see specifically Figure 2) arranged to cooperate with a centering pin 14 projecting from the outer surface 2' of said wall 2. The removable cover 7 is also provided, on its other edge 7" further from said reed (not shown), with a wall 15 which extends towards said base 5 to form a deflector 16 which, in cooperation with said groove 10 and said gripping member 9, maintains the weft yarn inclined within the giver gripper at an inclination greater than 45° to the base 5. Finally, the cover 7 is removably locked in position by screws passing through holes 17 in said wall 15 of the cover and screwed into holes 19 in a wall 18 of the gripper body 1, which rises in correspondence with that side of said gripping member closer to said reed (not shown). The figures also show a lightening hole 20 provided in the cover 7.

Claims: A giver gripper for a gripper loom, comprising a box-like gripper body of substantially U-shaped cross-section, having vertical lateral walls (2, 3) which terminate frontally in two vertical lateral points (4, 2"), that point (2") at the side of the gripper intended to lie closer to the loom reed being more forwardly projecting than the other, a substantially horizontal cover (7) located between the two lateral walls (2, 3) of said gripper body (1), said cover having a front tip (6) substantially between said two vertical points (2", 4) of the gripper body (1), said tip (6) being at a height above the base (5) of said gripper body (1) which is slightly lower than that of said vertical points (4, 2") of the gripper body (1), a gripping member (9) for the weft yarn positioned on said base (5) on that side intended to lie more distant from the reed, a guide and positioning groove (10) for the weft yarn and a deflector (16) for arranging the weft yarn inclined within the giver gripper, characterised in that said cover (7) is removably mounted on said gripper body (1) between that vertical wall (2) of said gripper body (1) intended to lie closer to the reed and said gripping member (9), and is provided with said guide and positioning groove (10) for the weft yarn on that side intended to lie closer to the reed, and with said deflector (16) on the other side. A giver gripper as claimed in claim 1, characterised in that said cover (7) with said guide and positioning groove (10) and said deflector (16) is mounted easily removable on said gripper body (1) by screwing that wall (15) thereof which is intended to lie more distant from the reed, and extending downwards to form said deflector, to a wall (2) of said gripper body (1) which rises on that side of said gripping member closer to the reed, said cover comprising on that side intended to lie closer to the reed a vertical wall (12) provided at its lower end with a hole (13) arranged to cooperate with a centering pin (14) projecting from that outer surface of said wall of said gripper body intended to lie closer to the reed. A giver gripper as claimed in claim 1 or 2, characterised in that said guide and positioning groove (10) for the weft yarn extends within said cover (7) approximately as far as the central longitudinal axis (11) thereof, so as to arrange the weft yarn, in cooperation with said deflector (16) and said gripping member (9), with an inclination greater than 45° to said base (5) of said gripper body (1). A giver gripper as claimed in claim 3, characterised in that said inclination of the weft yarn to said base (5) of said gripper body is about 60°.

Inventors: BORTOLI GIULIO, CORAIN LUCIANO, BORTOLI, GIULIO, CORAIN, LUCIANO
Applicants: SULZER TESSILE S R L, SULZER TESSILE S.R.L.
Application year: 1997
Main classification: D03D47
IPC codes: D03D47