Loop gripper with retaining element

Abstract

A loop gripper (10) for a tufting machine has a gripper body (11) with a gripper finger (12) extending in an extension direction E from a retained end (13) to a free end (14). On the gripper finger (12) underside (16), a cutting region (20) transitions into a sliding surface (19) at a transition point (21). A retaining element (35) near the transition point (21) is mounted to be pivotable about a pivot axis S relative to the gripper finger (12). The pivot axis S extends in a transverse direction Q at right angles to the extension direction E. The retaining element (35) is urged into a starting position A by a force, for example a spring force and/or a weight force. In the starting position A, a retaining surface (37) of the retaining element (35) extends obliquely or at right angles away from the sliding surface (19).

Claims

1. A loop gripper (10) for a tufting machine, the loop gripper comprising: a gripper finger (12) formed on a gripper body (11) and extending in an extension direction (E) from a retained end (13) to a free end (14), which gripper finger has on its underside (16) a cutting region (20) and immediately following the cutting region (20), between the cutting region (20) and the free end (14), a sliding surface (19) for yarn loops (26), wherein the gripper finger (12) has at the free end (14) an end protrusion (18) that protrudes beyond the sliding surface (19), a retaining element (35) which has a retaining surface (37) and which is mounted to be pivotable relative to the gripper finger (12) about a pivot axis (S) which extends in a transverse direction (Q) at right angles to the extension direction (E), a means for presetting a starting position for the retaining element by generating a force on the retaining element (35) to urge the retaining element (35) into a starting position (A) in which the retaining surface (37) extends away from the sliding surface (19) and faces toward the cutting region (20).

2. The loop gripper according to claim 1, wherein the force of the means for presetting the starting position is a spring force of a spring means (42) and/or a weight force of the retaining element (35) or of a retaining body (32) connected to the retaining element (35).

3. The loop gripper according to claim 1, wherein the sliding surface (19) of the gripper finger (12) adjoins two lateral planes which are arranged parallel to one another and at a distance (D) from one another in a transverse direction (Q), said lateral planes bounding an intermediate space.

4. The loop gripper according to claim 3, wherein the retaining element (35) engages in the intermediate space.

5. The loop gripper according to claim 4, wherein the retaining element (35) is arranged in the intermediate space.

6. The loop gripper according to claim 3, wherein the retaining element (35) has in the transverse direction (Q) a width (X) which is at most as large as the distance (D) between the two lateral planes.

7. The loop gripper according to claim 3, wherein the retaining element (35) has in the transverse direction (Q) a width (X) which is larger than the distance (D) between the two lateral planes.

8. The loop gripper according to claim 1, wherein the gripper finger (12) has two side surfaces (17) which adjoin the sliding surface (19), wherein the retaining element (35) does not come into contact with either of the two side surfaces (17), and wherein the retaining element (35) does not form with either of the two side surfaces (17) a gap for the passage of a yarn loop (26).

9. The loop gripper according to claim 1, wherein the cutting region (20) has a cutting edge (25).

10. The loop gripper according to claim 1, wherein the cutting region (20) is unsymmetrical in relation to a central plane passing through the gripper finger (12) in its extension direction (E).

11. The loop gripper according to claim 9, wherein the cutting region (20) has a smaller dimension than the sliding surface (19) in a transverse direction (Q) which is oriented parallel to the pivot axis (S).

12. The loop gripper according to claim 1, wherein the retaining element (35) has, on its side opposite the retaining surface (37), a run-in surface (38) which in the starting position (A) of the retaining element (35) encloses an acute first angle () with the sliding surface (19).

13. The loop gripper according to claim 12, wherein the retaining surface (37), in the starting position (A) of the retaining element (35), encloses with the sliding surface (19) a second angle () that is larger than the first angle ().

14. The loop gripper according to claim 1, wherein the retaining element (35) is arranged on a retaining body (32), the retaining body (32) being arranged on the gripper body (11).

15. The loop gripper according to claim 14, wherein the retaining element (35) is an integral part of the retaining body (32) or is arranged on the retaining body (32) in a pivotable manner.

16. The loop gripper according to claim 2, wherein the retaining element (35) is arranged on a retaining body (32), the retaining body (32) being arranged on the gripper body (11) and the retaining body (32) has the spring means (42).

17. The loop gripper according to claim 16, wherein the spring means (42) is an integral part of the retaining body (32).

18. The loop gripper according to claim 14, wherein the retaining body (35) is arranged in a recess (47) which is provided in the gripper finger (12) and which is open toward the underside (16).

Description

(1) Advantageous embodiments of the loop gripper will become apparent from the dependent claims, the description and the drawing. Preferred exemplary embodiments of the loop gripper will be explained in detail below with reference to the appended drawing. In the drawing:

BRIEF DESCRIPTION OF THE DRAWINGS

(2) FIG. 1 shows a perspective partial view of a first exemplary embodiment of a loop gripper,

(3) FIG. 2 shows a perspective partial view of the loop gripper of FIG. 1,

(4) FIG. 3 shows a second exemplary embodiment of a loop gripper in a perspective partial view, and

(5) FIG. 4 shows a third exemplary embodiment of a loop gripper in a perspective partial view.

DETAILED DESCRIPTION

(6) A first exemplary embodiment of a loop gripper 10 is illustrated in FIGS. 1 and 2. The loop gripper 10 has a gripper body 11, on which a gripper finger 12 is formed. The gripper finger 12 is an integral part of the gripper body 11 and extends in an extension direction E from a retained end 13 to a free end 14. The gripper finger 12 has an upper side 15 which, when producing cut pile, is assigned to a backing of the textile material produced. The gripper finger 12 also has an underside 16 opposite the upper side 15. Narrow sides of the gripper finger 12 are provided on the upper side 15 and on the underside 16. Said narrow sides are connected to one another by two side surfaces 17. The two side surfaces 17 are arranged at a distance from one another in a transverse direction Q at right angles to the extension direction E.

(7) The direction at right angles to the transverse direction Q and at right angles to the extension direction E is referred to as the height direction H.

(8) The gripper finger 12 forms a hook at its free end 14. This is achieved in that an end protrusion 18 protrudes substantially in the height direction H away from the adjoining region of the underside 16 of the gripper finger 12.

(9) On the underside 16, the end protrusion 18 is adjoined by a sliding surface 19. The sliding surface 19 extends from the end protrusion 18 to a cutting region 20 of the gripper finger. The sliding surface 19 transitions into the cutting region 20 at a transition point 21. In the first exemplary embodiment of the loop gripper 10, the cutting region 20 is of unsymmetrical shape in relation to a central plane through the gripper finger 12, which is defined by the extension direction E and the height direction H. Provided in the cutting region 20 is a cutting edge 25 which preferably cooperates with a cutting blade (not shown) in order to cut yarn loops 26. A cutout 27 is formed in the gripper finger 12 laterally in the cutting region 20. The cutting blade moves along the gripper finger 12 and along the cutting edge 25 on the side opposite the cutout 27. The cutout 27 helps the cutting blade, together with the cutting edge 25, to be able to cut a yarn loop 26 close to the apex, that is to say in the region of the central plane through the gripper finger 12, so that as far as possible pile threads of equal length are obtained. The cutout 27 is open in the height direction H on the underside 16 and in the transverse direction Q on one of the two sides of the gripper finger 12.

(10) On the side opposite the sliding surface 19, the cutting region 20 is adjoined by a retained region 28 of the gripper body 11 having the retained end 13 of the gripper finger 12.

(11) The loop gripper 10 according to the first exemplary embodiment also has a retaining body 32. The retaining body 32 has an attachment part 33, by means of which it is attached to the gripper body 11 in the retained region 28, for example with a form fit and/or with a force fit and/or by a material bond (FIG. 1). Starting from the attachment part 33, a connecting part extends over the cutting region 20 to the free end 14 of the gripper finger 12. The connecting part 34 engages, so to speak, over the cutting region 20. At its end opposite the attachment part 33, a retaining element 35 is arranged on the connecting part 34 of the retaining body 32.

(12) In the exemplary embodiment described here, the retaining element 35 has a bearing surface 36 which faces toward the sliding surface 19 and in a starting position A bears against a portion of the sliding surface 19. In the extension direction E, the bearing surface 36 is adjoined by a retaining surface 37 on the side facing toward the cutting region 20. On the side opposite the retaining surface 37, which side faces toward the free end 14 of the gripper finger 12, the retaining element 35 has a run-in surface 38.

(13) In the starting position A, the run-in surface 38 encloses a first angle with the sliding surface 19. The first angle is configured as an acute angle and is preferably smaller than 70 or smaller than 60 or smaller than 45. In the starting position A, the retaining surface 37 encloses a second angle with the sliding surface 19 at least in the region of the retaining surface 37 directly adjoining the sliding surface 19, said second angle being larger than the first angle and preferably forming approximately a right angle and being for example in the range from 80 to 100.

(14) The retaining body 32 has a means for presetting the starting position and for example a spring means 42 which, in the first exemplary embodiment, is formed by the connecting part 34 of the retaining body 32. With the aid of the spring means 42, the retaining element 35 is biased into its starting position a. In the exemplary embodiment, the bearing surface 36 bears against the sliding surface 19 in the region of the transition point 21. It is preferred if the retaining surface 37 in the starting position A is arranged close to the transition point 21. Preferably, the distance in the extension direction E between the transition point 21 and the retaining surface 37 in the starting position A is at most 5 mm or at most 2 mm to 3 mm.

(15) As illustrated in FIGS. 1 and 2, in the first exemplary embodiment of the loop gripper 10 the retaining body 32 is designed as an integral part without any seam or join. The attachment part 33, the connecting part 34 and the retaining element 35 merge integrally into one another without any seam or join.

(16) The retaining element 35 can be pivoted out of the starting position and into a deflected position B (FIG. 2) about a pivot axis S counter to the spring force of the spring means 42. The pivoting movement of the retaining element 35 is not triggered by external control means but rather is caused exclusively by the spring means 42 of the retaining body 32 and the yarn loops 26 moved into the cutting region 20.

(17) The first exemplary embodiment of the loop gripper 10 operates as follows:

(18) When producing cut pile, the yarn loops are gripped by the gripper finger 12 and are located initially between the cutting region 20 and the end protrusion 18, so that the region around the apex of the yarn loop 26 bears against the sliding surface 19. By virtue of a relative movement between the backing and the loop gripper 10, the yarn loop 26 moves along the sliding surface 19 toward the cutting region 20 until it comes into contact with the retaining element 35 and in the present case the run-in surface 38. By a continued relative movement in the extension direction E, the yarn loop 36 presses against the run-in surface 38 and pivots the retaining element 35 about the pivot axis S out of the starting position A and into the deflected position B counter to the spring force of the spring means 42. A gap is thus created between the bearing surface 36 and the sliding surface 19, through which gap the yarn loop 26 can pass from the sliding surface 19 into the cutting region 20 (diagram shown in dashed line in FIG. 2). Since the first angle is an acute angle, the force for deflecting the retaining element 35 into the deflected position B is sufficiently low.

(19) Once the yarn loop 26 is located in the cutting region 20, it is cut there in the region of its apex by means of a cutting blade. During this, the yarn loop 26 cannot escape from the cutting region 20 since it butts against the retaining surface 37 of the retaining element 35 and is held back then at the latest. This leads to a considerably improved quality of the cut pile produced. Since, in the exemplary embodiment, the second angle is larger than the first angle , a yarn loop 26 can deflect the retaining element 35 out of the starting position A when the yarn loop moves into the cutting region 20. In the case of a reversed relative movement of the loop gripper 10 relative to the backing, on account of the larger angle the required force that would be necessary in order to move a yarn loop 26 through between the retaining element 35 and the gripper finger 12 would be too great, so that the yarn loops 26 are securely held in the cutting region 20.

(20) FIG. 3 shows a modified second exemplary embodiment of the loop gripper 10. The gripper body 11 with the gripper finger 12 is identical to the first exemplary embodiment shown in FIGS. 1 and 2, so that reference can be made to the description above.

(21) The main difference of the second exemplary embodiment shown in FIG. 3 compared to the first exemplary embodiment of FIGS. 1 and 2 lies in the fact that the retaining element 35 is arranged as a separate part on the retaining body 32. The retaining element 35 is mounted at the end of the connecting part 34 opposite the attachment part 33 in such a way as to be able to pivot about the pivot axis S. While the pivot axis S in the first exemplary embodiment is arranged in the region of the retained portion 28, in the second exemplary embodiment the pivot axis S extends below the sliding surface 19. In both exemplary embodiments, the pivot axis S is arranged at a distance from the sliding surface 19 in the height direction.

(22) Another difference compared to the first exemplary embodiment lies in the fact that, in the second exemplary embodiment shown in FIG. 3, the spring means 42 is formed separately from the connecting part 34. The spring means 42 is formed by a spring-elastic finger 43 which extends from the attachment part 33 to the retaining element 35 and applies a spring force to the retaining element 35 on the side opposite the bearing surface 36 in the height direction and presses the bearing surface 36 against the sliding surface 19. The spring-elastic finger 43 is for example an integral part of the retaining body 32.

(23) The second exemplary embodiment of the loop gripper 10 shown in FIG. 3 otherwise corresponds to the first exemplary embodiment shown in FIGS. 1 and 2. The mode of operation is in principle the same as in the first exemplary embodiment, so that reference can be made to the description above.

(24) A third embodiment of the loop gripper 10 is illustrated schematically in FIG. 4. In this embodiment, the retaining body 32 with the retaining element 35 is pivotably mounted within a recess 47 of the gripper finger 12. In the starting position A, the retaining element 35 protrudes out of the recess 47 and protrudes beyond the sliding surface 19 and/or the underside 16 in the cutting region 20 of the gripper finger 12. The recess 47 is to this end open toward the underside 16. In the transverse direction Q, the recess 47 is closed by side cheeks which each have a part of the side surfaces 17.

(25) In the illustrated exemplary embodiment, the retaining element 35 has an approximately triangular shape. Unlike in the previous exemplary embodiments, the first angle is configured as an obtuse angle and is preferably larger than 100 and more preferably larger than 120 or 130. The second angle may be configured as a substantially right angle and, as in the other exemplary embodiments, may lie for example in the range from 80 to 100.

(26) In this embodiment, the means for presetting the starting position may generate its force for urging the retaining element 35 into the starting position A by the weight force of the retaining body 35. In addition or as an alternative, a spring means 42 may also be provided. When a yarn loop 26 moves along the gripper finger 12 in the extension direction E, the retaining element 35 is pivoted into the recess 47 counter to the weight force and/or spring force so that the yarn loop 26 can pass over the retaining element 35 from the sliding surface 19 into the cutting region 20. A pivoting movement of the retaining element 35 out of the starting position A is preferably possible only in one direction of pivoting and for example in the clockwise direction about the pivot axis S. This prevents yarn loops 26 located in the cutting region 20 from being able to leave the cutting region 20 by moving the retaining element 35 into the recess 47.

(27) In all exemplary embodiments, at least the retaining surface 37 and/or the entire retaining element 35 has in the transverse direction Q a width X which is at most as large as the distance D between two lateral planes which adjoin the sliding surface 19 from opposite sides in the transverse direction Q. The two lateral planes are oriented parallel to one another and are defined by the extension direction E and the height direction H. Each lateral plane contains an edge between the sliding surface 19 and the respectively adjoining side surface 17. The two lateral planes define an intermediate space, within which the retaining surface 37 and/or the run-in surface 38 and preferably the retaining element 35 is arranged. In the second exemplary embodiment shown in FIG. 3, bearing means provided for pivotably mounting the retaining element 35 on the retaining body 32, such as pins, bolts or the like, may pass through one or both lateral planes.

(28) In the preferred exemplary embodiments, the retaining plane 37 and the run-in surface 38 are arranged and configured centrally and preferably symmetrically in relation to a central plane which passes through the gripper finger 12 between the two lateral planes. Other parts of the retaining body 32 may be located outside of the intermediate space between the lateral planes or may pass through at least one of the lateral planes.

(29) The invention relates to a loop gripper 10 for a tufting machine. The loop gripper 10 has a gripper body 11 with a gripper finger 12 which extends in an extension direction E from a retained end 13 to a free end 14. On the underside 16 of the gripper finger 12, there is a cutting region 20 which transitions into a sliding surface 19 at a transition point 21. Located in the region of the transition point 21 is a retaining element 35 which is mounted so as to be pivotable about a pivot axis S relative to the gripper finger 12. The pivot axis S extends in a transverse direction Q at right angles to the extension direction E. The retaining element 35 is urged into a starting position A by a force, for example a spring force of a spring means 42 and/or a weight force. In the starting position A, a retaining surface 37 of the retaining element 35 extends obliquely or at right angles away from the sliding surface 19.

LIST OF REFERENCE SIGNS

(30) 10 loop gripper 11 gripper body 12 gripper finger 13 retained end of the gripper finger 14 free end of the gripper finger 15 upper side 16 underside 17 side surface 18 end protrusion 19 sliding surface 20 cutting region 21 transition point 25 cutting edge 26 yarn loop 27 cutout 28 retained region of the gripper body 32 retaining body 33 attachment part 34 connecting part 35 retaining element 36 bearing surface 37 retaining surface 38 run-in surface 42 spring means 43 finger 47 recess first angle second angle A starting position B deflected position D distance between the lateral planes E extension direction H height direction Q transverse direction S pivot axis X width of the retaining surface or of the retaining element