Title of Invention

GRIPPER AND DEVICE FOR INSERTING A WEFT THREAD

Abstract

ABSTRACT A GRIPPER AND A DEVICE FOR INSERTING A WEFT THREAD The invention relates to a gripper and a device for inserting a weft thread and also to a weaving machine having such a device. The gripper for inserting a weft thread comprises a casing, a clamping part with a hook-shaped clamping portion to pick up a weft thread a pivoting clamping tongue, which interacts with the clamping portion, whereby the clamping tongue is connected to a pivoting shaft part and exposed to a torsion spring, in order to clamp the weft thread, and an actuating element for the clamping tongue, wherein the torsion spring is provided by a torsion rod spring and concentrically arranged in the pipe-shaped shaft part, whereby on one end the torsion rod spring is arranged on the shaft part by a torque proof connection and on the other end the torsion rod spring is connected to the casing through adjusting means to adjust the clamping force of the clamping tongue. Fig. 2.

Full Text

The innovation relates to a gripper and a device for inserting a weft thread and also to a weaving machine having such a device. Grippers with differently designed thread clamps are known. The said clamps consist essentially of a fixed clamping part, a moveable claming part, a spring element and actuating member and differ from one another in the type of clamping and the clamping movement. In one gripper, the fixed clamping part is designed as a housing with a hook-shaped clamping portion for receiving a weft thread and the moveable clamping part is designed as a clamping tongue which, under the action of a helical spring, is displaceable in the longitudinal direction of the housing in order to clamp the weft thread. The actuating member is connected to the clamping tongue, in order to guide and displace the clamping tongue in the housing counter to the spring action. In another gripper, the fixed clamping part is designed as a housing with a hook-shaped clamping portion for receiving a weft thread and the moveable clamping part is designed as a clamping lever which, under the action of a helical spring, is pivoted about an axis running transversely to the longitudinal direction of the housing, in order to clamp the weft thread. The use of the helical spring proves to be a disadvantage, because space and means for holding and/or guiding said spring have to be provided for this purpose. The object on which the innovation is based is to improve a gripper. Accordingly the present invention provides a gripper for inserting a weft thread, comprising a casing, a clamping part with a hook-shaped clamping portion to pick up a weft thread a pivoting clamping tongue, which interacts with the clamping portion, whereby the clamping tongue is connected to a pivoting shaft part and exposed to a torsion spring, in order to clamp the weft thread, and an actuating element for the clamping tongue, characterized in that the torsion spring is provided by a torsion rod spring and concentrically arranged in the pipe-shaped shaft part, whereby on one end the torsion rod spring is arranged on the shaft part by a torque proof connection and on the other end the torsion rod spring is connected to the casing through adjusting means to adjust the clamping force of the clamping tongue. The advantages capable of being achieved by means of the innovation are to be seen essentially in that the gripper has a minimum number of individual parts, has a very low mass and operates with a low clamping force. Accordingly the present invention also provides a device for inserting a weft thread with a gripper band and with a gripper such as herein described, wherein the casing is attached to the gripper band and that the clamping part has a projection, which overlaps the gripper band . The innovation is explained below with reference to the accompanying drawings in which: fig. 1 shows a view of a gripper according to the innovation; fig. 2 shows a section along the line II-II in fig. 1; fig. 3 shows a view in the direcfion of the arrow D in fig. 1; fig. 4 shows a section along the line IV-IV in fig. 1; fig. 5 shows a section along the line V-V in fig. 1, and fig. 6 shows a section along the line VI-VI in fig. 1. Reference is made to figures 1 and 2 which show a gripper 1 with a portion 2 of a gripper strip. The gripper 1 has a housing 4, a clamping part 5, a clamping unit 6 and a shackle 7 for actuating the clamping unit. The housing 1 consists of plastic and has a bore 8 for receiving the clamping unit 6. The clamping part 5 consists of metal and is connected to the housing 4. The clamping part 5 has a portion 11 for fastening to the housing 4, a hook-shaped portion 12 for receiving a weft thread and an extension 13 which engages over the gripper strip 2 in order to prevent the warp threads from being damaged when a weft thread is inserted. The hook-shaped portion 12 is provided with a clamping surface (not illustrated) . A bore 14 is formed in the hook-shaped portion. The clamping unit 6 comprises a tubular shank part 21, a clamping tongue 22 and a torsion bar 23 which is arranged in the shank part and connected at one end to the shank part 21 by means of a pin 24. The shank part 21 has two annular extensions 25, in order to support the shank part 21 in the region of the shackle 7. The clamping tongue 22 is provided with a connection part 2 6 which is connected at one end to the shank part and at the other end has a guide stud 27. The clamping tongue 22 is connected, adjacent to the guide stud 27, to the connection part 26, in such a way that the clamping tongue 22 projects radially from the connection part 26. The clamping unit has a sleeve 28 with an engagement orifice 29 for a tool, said sleeve being fastened to the other end of the torsion bar 23 in such a way that the engagement orifice is freely accessible. The sleeve 28 is arranged rotationally moveably in the bore 8 of the housing 1 and is connected to the torsion bar 23 by means of a pin 30. The sleeve 2 8 serves, furthermore, for securing the clamping unit 5 in the housing 1. Reference is made to figures 3 and 4 . As these figures show, clamping surfaces 33, 34 are arranged at 45° in each case on the hook-shaped portion 12 and on the clamping tongue 22 and are provided with grooves 35. The advantage of this is that the clamping surfaces are enlarged or the number of grooves is increased, so that the clamping length for the weft thread 36 is extended, friction is greater and the clamping force can be lower, in order to avoid damage to the weft thread. As fig. 5 shows, the shackle 7 for actuating the clamping part 5 is connected to the shank part 21 by means of clamps. A screw 37 is provided for this purpose. As fig. 6 shows, a clamping block 41 is arranged in the housing 4 with a screw 42, in order to tension the sleeve 28 firmly. As already mentioned, the clamping unit 6 is secured in the housing 1, using the sleeve 28. Normally, the clamping force is set according to the properties of a weft thread. For this purpose, the clamping of the sleeve 28 is canceled by the release of the screw 42 and the sleeve is rotated by means of a tool (not illustrated). The rotational movement [sic] the clamping tongue to pivot with respect to the hook-shaped portion 12. The clamping of the sleeve 28 is thereafter restored by the tightening of the screw (fig. 6) . During the insertion of a weft thread, the shackle 7 is displaced by an actuator (not illustrated) provided in the running path of the gripper, and, as a result, the clamping tongue 22 is pivoted with respect to the hook-shaped portion 12 and the weft thread is received in the hook-shaped portion. The return of the clamping tongue takes place by virtue of the elasticity of the clamping unit 6. WE CLAIM : 1. Gripper for inserting a weft thread, comprising a casing (1), a clamping part (5) with a hook-shaped clamping portion (12) to pick up a weft thread a pivoting clamping tongue (22), which interacts with the clamping portion, whereby the clamping tongue (22) is connected to a pivoting shaft part (21) and exposed to a torsion spring (23), in order to clamp the weft thread, and an actuating element (7) for the clamping tongue, characterized in that the torsion spring is provided by a torsion rod spring (23) and concentrically arranged in the pipe-shaped shaft part (21), whereby on one end the torsion rod spring (23) is arranged on the shaft part (21) by a torque proof connection and on the other end the torsion rod spring is connected to the casing through adjusting means (28, 41,42) to adjust the clamping force of the clamping tongue. 2. Gripper as claimed in claim 1, wherein the torsion rod spring (23) is guided respectively supported in the section of the hook-shaped clamping portion. 3. Gripper as claimed in any one of claims 1 to 2, wherein each of the hook- shaped clamping portion (12) and the clamping tongue (22), has one clamping area (33, 34) with grooves (35). 4. Gripper as claimed in claim 3, wherein the clamping areas (33, 34) are arranged in respect to the gripper band (2) at an angle of approximately 45 degrees. 5. Gripper as claimed in any one of claims 1 to 4, wherein a connecting element (26), which is pivotably supported in the casing, connected to the shaft part (21) and supports the clamping tongue (22). 6. Gripper as claimed in claim 5, wherein the connecting element (26) is guided or supported in the section of the hook-shaped clamping portion (12). 7. Gripper as claimed in claim 1, wherein the actuating element (7) for the clamping tongue (22) is mounted on the shaft part (21). 8. Device for inserting a weft thread with a gripper band (2) and with a gripper as claimed in any one of claims 1 to 7, wherein the casing (4) is attached to the gripper band (2) and that the clamping part (5) has a projection (13), which overlaps the gripper band (2). 9. Weaving machine with a device as claimed in claim 8. 10. Gripper for inserting a weft thread, substantially as hereinabove described and illustrated with reference to the accompanying drawings. 11. Device for inserting a weft thread, substantially as hereinabove described and illustrated with reference to the accompanying drawings.

Documents:

in-pct-2001-1750-che abstract.pdf

in-pct-2001-1750-che claims-duplicate.pdf

in-pct-2001-1750-che claims.pdf

in-pct-2001-1750-che correspondnece-others.pdf

in-pct-2001-1750-che correspondnece-po.pdf

in-pct-2001-1750-che description(complete)-duplicate.pdf

in-pct-2001-1750-che description(complete).pdf

in-pct-2001-1750-che drawings.pdf

in-pct-2001-1750-che duplicate-duplicate.pdf

in-pct-2001-1750-che form-1.pdf

in-pct-2001-1750-che form-26.pdf

in-pct-2001-1750-che form-3.pdf

in-pct-2001-1750-che form-5.pdf

in-pct-2001-1750-che petition.pdf