EP3406781A1 - Gripper for tufting machine - Google Patents

Abstract

The invention relates to a gripper (1) for a tufting machine, which has a base body (2) and an insert body (3). The gripper (1) has a holding section (4) and a guide section (5) in the longitudinal direction. The guide section (5) ends in the longitudinal direction facing away from the holding section (4) in a hook (14) having an inner side (15), in which a joint gap (18) between the base body (2) and the insert body (3) is arranged , The gripper (1) according to the invention is characterized in that in the guide section (5) of the gripper (1) on the base body (2) a stop means (6) is arranged, against which the insert body (3) in the longitudinal direction to the holding portion (4) is struck in order to limit the joint gap (18) in the inside of the hook (14) in its size.

Description

Grippers for tufting machines are known in many different designs. It is the task of grippers in tufting machines to remove the yarn from a needle that transports the yarn through a substrate to form a loop. Often this loop is cut open immediately after its production. For this purpose, the gripper works together with a knife, which rests on the gripper and slides along it. To protect the gripper against excessive wear by the knife, an insert body made of a wear-resistant material is often arranged on the main body of the gripper and usually soldered.

Such grippers are for example in EP 2 412 856 A1 . EP 1 953 290 A1 . EP 0 200 810A1 and DE 23 41 567 A1 shown.

The EP 2 412 860 A9 also shows such a gripper. To secure the insert body in its nominal position during the production of the gripper (in particular during the soldering process), this has in one embodiment, a spring element, which is arranged in the holding portion of the base body. The spring element is very delicate and thus limited in its effect.

All the above-mentioned grippers have in common that a considerable gap between the base body and the insert body may be present. At a point where the yarn makes contact with this nip, the yarn will wash out the relatively soft solder over time and will then be damaged by the edges of the base body and the insert body. This results in the carpet surface being uneven and shaggy due to the broken filaments. This problem preferably occurs on a hook inside, because here the yarn is forced to contact frequently to a gap present there, since this area serves to receive the yarn from the needle and thus forcibly one Relative movement between yarn and gripper occurs. In some cases, it can even happen that the yarn gets jammed and then breaks.

Starting from this prior art, it is the object of the present invention to provide a gripper in which the above-mentioned problems are avoided or reduced and a uniform appearance of the product is obtained.

This object is achieved by a gripper having a base body and an insert body, wherein the gripper has a holding portion and a guide portion in its longitudinal direction. The guide portion ends in the longitudinal direction facing away from the holding portion in a hook. The hook has an inner side, in which a joint gap between the base body and the insert body is arranged. According to the invention a stop means is arranged in the guide portion of the gripper on the base body, against which the insert body is struck in the longitudinal direction of the holding portion. By this design of the body of the joint gap in the inside of the hook is limited in size. Accordingly, an attachment means is arranged in the guide portion of the gripper on the insert body, which is struck on the stop means of the main body in the longitudinal direction of the holding portion. In the manufacture of the gripper, the base body and the insert body must be joined and connected to each other. A preferred way to make the connection may be soldering. During the soldering process or during cooling and curing of the solder, the position of the insert body relative to the base body may shift. The gap between the base body and the insert body can grow uncontrollably and differently at different locations. A comparable shift can also occur during curing of an adhesive bond when the base body and the insert body are bonded. Irrespective of a particular type of connection, the abutment means on the base body and the abutment means on the insert body determine a relative position of the bodies in the longitudinal direction relative to each other, in which in particular the joint gap in the hook inner side has a limited size. Due to the limited size of the joint gap in the inside of the hook, the risk is reduced that the yarn at the edges of the base body and the insert body, in the inside of the Hakens limit the joint gap, is damaged. The insert body is struck in the longitudinal direction according to the invention at three points on the base body, wherein in each case a joint gap between the bodies, which are struck against each other, is present. At both ends of the insert body in the longitudinal direction of the insert body is covered by the main body. These two stops act in the longitudinal direction, but are oriented differently. The third and inventive stop acts in the same orientation in the longitudinal direction as the stop in the holding area. The arrangement in the guide area limits this third stop the size of the joint gap in the hook inside.

The longitudinal direction of the gripper is defined by the cutting edge, which is formed in a known manner in the guide portion on the insert body. Perpendicular to the longitudinal direction, the width direction is the direction in which the two larger flat sides of the narrow gripper are spaced apart. Perpendicular to both of the above is the height direction, which points in the direction of the substrate in the installed state of the gripper in the machine. The holding portion of the gripper is used to attach the gripper to the tufting machine and forms an end region of the gripper in the longitudinal direction. Frequently, several grippers are combined in one module and the holding section is then defined in a so-called module block.

The hook prevents the recorded loops from sliding off the hook again. For this purpose, the hook may extend in the height direction from the cutting edge or from an extension of the cutting edge in such a way that the extension of the gripper in the height direction increases. In other words, the entire guide region forms an elongate hook-shaped body which faces away from the holding section. On the hook, in particular, an inner side is formed whose surface perpendicular is oriented approximately in the longitudinal direction of the holding portion. The main body and the insert body extend into the hook and form a joint gap in the course of the inside of the hook. It may be advantageous if this joint gap is displaced far to the outer edge of the hook inner surface. A tensioned loop will not be in contact with this joint as often. Particularly preferably, the inside of the hook is at least 50% by the Insert body formed. But it is also conceivable that the inside is formed to 65% or 80% by the insert body.

It is advantageous if the stop means on the base body in the guide portion in the end region in the longitudinal direction in the direction away from the holding portion direction is arranged. Thereby, the distance in the longitudinal direction between the stop means and the distal end of the holding portion of the gripper is small compared to its entire extension in the longitudinal direction. Scattering in the dimensions of the base body, which amount to fractions of the total extent in conventional production methods for such basic bodies, then correspondingly smaller in this end region. The insert body is encompassed in a preferred embodiment in the longitudinal direction of the body at both ends, so that a maximum amount of inaccuracy in the longitudinal positioning while can not be exceeded. However, the base body and the insert body in the longitudinal direction are relatively long, so that the variations in the length dimensions of both parts due to the production are not negligible. Due to the arrangement of the stop means and the attachment means in the end portion remote from the holding portion, the deviations in this end portion are correspondingly smaller. Since the abutment means and the abutment means act together for exact positioning, the two positioning means must be arranged correspondingly on the main body and on the insert body. In the holding section, the exact positioning of both parts in the longitudinal direction in the embodiments according to the invention is not critical.

Preferably, the distance in the longitudinal direction of the stop means from the end of the guide portion in the direction of the holding portion be at least twice as large as the distance in the longitudinal direction of the stop means of the holding portion facing away from the end of the guide portion of the gripper. The difference of the distances can also be at least a factor of 3 or at least a factor of 4 or more.

Preferably, the stop means is firmly fixed to the base body and the attachment means fixed to the insert body. For the purposes of this invention, solid is understood to be immovable and non-deformable relative to the respective body. Especially resilient elements which are known from the prior art are not fixedly arranged in this sense.

In an advantageous embodiment, the stop means on a stop surface element with a surface perpendicular, which has in the longitudinal direction to the end remote from the holding portion of the guide portion of the gripper. Furthermore, it is preferred that the abutment means comprises an abutment surface element arranged on the insert body, with a surface perpendicular which points in the longitudinal direction to the holding section. It is also advantageous if the two surface elements are arranged adjacent to each other. The surface elements with the corresponding orientation can be relatively small or even present at curved surfaces almost only selectively. If there are no correspondingly aligned surface elements, there is the possibility that the bodies are not positioned exactly to one another. According to the invention, only approximately correspondingly aligned surface elements may be present. Adjacent may have different meanings in the present specification. On the one hand, the surface elements can touch each other directly touching each other, so as to ensure the exact positioning. On the other hand, it is also provided according to the invention that an adhesive (such as solder, adhesive or the like) is arranged between the surface elements, that is to say between the base body and the insert body. This intermediate layer can be taken into account and calculated in the interpretation of the relative position of the sling and the attachment means. Likewise, an adhesive may be present between the abutment means and the abutment means, if it is mentioned that the insert body is struck on the base body.

The stop means may be formed by a projection on the base or insert body. The attachment means may then be formed complementary to the stop means as a depression on the insert or body. In a preferred embodiment, the stop means is a projection on the base body and the attachment means a recess adapted to the insert body. Surface elements of the recess are then with or without an intermediate layer of an adhesive to surface elements of the projection, whereby the relative position of the body is set to each other exactly. The projection may be formed integrally with the base or insert body and thus in particular consist of the same material. The projection may be formed by an additional component which is fixed to one of the bodies.

In an advantageous embodiment, the base body and the insert body do not overlap in a width direction. In particular, both bodies are then equipped with a same width. However, this does not exclude that one of the bodies or both bodies are partially reduced in width. For example, at the end of the gripper remote from the holding section, there may be reductions in the width of the body and / or the insert body, for example to provide clearance for the tufting needle or to sharpen the gripper to facilitate picking up the loop. Other shape features are known on grippers which adapt the width of the bodies and which are all expressly compatible with the present invention. It is also possible that the gripper is rounded at its end remote from the holding section end in different directions. In this respect, the flat sides of the gripper are not necessarily flat on the whole surface. However, embodiments of the concept of the invention are encompassed in which the insert body is accommodated, for example, in a pocket of the base body and thus has, at least in sections, a smaller width than the base body at its widest point.

Between the base body and the insert body, an adhesive, in particular a solder is preferably arranged. However, any other adhesives, such as adhesives, are useful in the present invention. Furthermore, it is preferred if the adhesive is present at each point at which the base body and the insert body adjoin one another. Likewise, it is also possible that in various adjacent areas, such as in the area of the stop and the attachment means, there is no adhesive and the body touch directly.

Fig. 1

Figur 1 zeigt einen erfindungsgemäßen Greifer in einer Ansicht auf eine Flachseite, wobei der Greifer in einem Greiferblock gehalten ist.

Fig. 2

Figur 2 zeigt einen weiteren erfindungsgemäßen Greifer, wiederum in einer Ansicht auf eine Flachseite.

Fig. 3

Figur 3 zeigt eine vergrößerte Ansicht des Endbereichs des Greifers aus Figur 1

Fig. 4a

Figur 4a zeigt den Grundkörper aus der Figur 3

Fig. 4b

Figur 4b zeigt den Einsatzkörper aus der Figur 3

Fig. 5

Figur 5 zeigt einen weiteren erfindungsgemäßen Greifer

Fig. 6

Figur 6 zeigt einen weiteren erfindungsgemäßen Greifer

The insert body may have carbide or consist entirely of hard metal or other particularly wear-resistant material. The main body preferably comprises a tool steel or consists entirely of such. All adapted for the particular application materials are conceivable for the main body and the insert body. By the basic idea there is no Restrictions on the choice of materials, provided that on the bodies slings and / or attachment means are formable and they can be added with an adhesive.

Fig. 1

FIG. 1 shows a gripper according to the invention in a view on a flat side, wherein the gripper is held in a gripper block.

Fig. 2

FIG. 2 shows a further gripper according to the invention, again in a view on a flat side.

Fig. 3

FIG. 3 shows an enlarged view of the end portion of the gripper FIG. 1

Fig. 4a

FIG. 4a shows the main body of the FIG. 3

Fig. 4b

FIG. 4b shows the insert body from the FIG. 3

Fig. 5

FIG. 5 shows a further gripper according to the invention

Fig. 6

FIG. 6 shows a further gripper according to the invention

FIG. 1 shows a gripper 1 according to the invention in a view of a flat side 16, wherein the gripper 1 is held in a gripper block 17. For all figures, details have been largely omitted in the drawings for the sake of simplicity. For example, between the main body 2 and the insert body 3 never an extended joint gap is shown, but only a simple line drawn at the joint. Also, the longitudinal direction and the height direction are indicated. Orientation is the same for all subsequent drawings. At the gripper block 17 of FIG. 1 Further grippers 1 can be fixed, which are covered by the gripper 1 shown. In this respect serves FIG. 1 just for a rough overview.

FIG. 2 shows a further gripper 1 according to the invention, again in a view of a flat side 16. For clarity, the holding portion 4 and the guide portion 5 are indicated with braces. Both the base body 2 and the insert body 3 extend into the holding portion 4 and into the guide portion 5 and into the hook 14. The hook forms, inter alia, an inner side 15, which is oriented to the holding portion 4. In this embodiment, the insert body 3 forms a bearing means 7, which from the Insert body 3 protrudes and with a stop means 6, which is recessed on the base body 2, cooperates. The stop means 6 on the main body 2 has a vertical surface perpendicular 9, which is indicated as an arrow starting from the stop means 6. Likewise, the surface perpendicular 11 of the attachment means 7 of the insert body 3 is indicated as an arrow starting from the attachment means 7. On the inner side 15 of the hook 14, the main body 2 and the insert body 3 form a joint gap 18, which, however, is again shown only as a simple line.

FIG. 3 shows an enlarged view of the end portion of the gripper 1 from FIG. 1 , The end of the gripper 1 has a sharpening, which is illustrated by the beveled edge 19 on the base body 2. The insert body 3 forms the largest part of the inner side 15 of the hook 14. On the base body 2, a stop means 6 is formed, which projects from the base body 2. Accordingly, an attachment means 7 is formed on the insert body 3, which abuts the stop means 6 on the base body 2. Again, the joint gap 18 between the main body 2 and the insert body 3 is drawn only as a simple line, although a very noticeable gap between the parts may be present.

FIG. 4a shows the main body 2 from FIG. 3 , FIG. 4b shows the insert body 3 from FIG. 3 , The two bodies are aligned in the longitudinal direction exactly to each other, however, is displaced for better understanding of the insert body in the opposite height direction H down. The main body has a projection 12, which has a stop surface region 8 with a surface perpendicular 9, which is shown as an arrow on. The insert body 3 has a recess 13. In the recess 13 is a contact surface element 10 with a vertical surface 11, which is shown as an arrow before.

FIG. 5 shows a further gripper according to the invention 1. Notwithstanding the previous embodiments, the insert body 3 has a projection 12 which is arranged in the longitudinal direction L at the end of the insert body 3.

FIG. 6 shows a further gripper invention 1. In this embodiment, the attachment means 7 on the insert body 3 is again provided in the longitudinal direction L at the end of the insert body 3, but in this Example at the height H lower region of the insert body 3. On the base body 2, a corresponding stop means 6 is formed. LIST OF REFERENCE NUMBERS 1 grab 2 body 3 insert body 4 holding section 5 guide section 6 slings 7 investment funds 8th Stop surface element 9 Surface perpendicular of the stop surface element 10 Contact surface element 11 Surface perpendicular of the contact surface element 12 head Start 13 deepening 14 hook 15 Inside of the hook 16 flat side 17 gripper block 18 joining gap 19 Anschliffkante B width direction H height direction L longitudinal direction

Claims (14)

Gripper (1) for a tufting machine, comprising a base body (2) and an insert body (3), wherein the gripper (1) in the longitudinal direction (L) has a holding portion (4) and a guide portion (5), wherein the guide portion ( 5) in the longitudinal direction (L) facing away from the holding section (4) ends in a hook (14), wherein the hook has an inner side (15) in which a joint gap (18) between the base body (2) and the insert body (3) is arranged, characterized in that in the guide portion (5) of the gripper (1) on the base body (2) a stop means (6) is arranged, against which the insert body (3) in the longitudinal direction (L) to the holding portion (4) is struck, to limit the joint gap (18) in the inside (15) of the hook (14) in its size. Gripper (1) according to claim 1, characterized in that in the guide portion (5) of the gripper on the insert body (3) an abutment means (7) on the stop means (6) of the main body in the longitudinal direction (L) to the holding portion (4) is struck , is arranged. Gripper (1) according to claim 2, characterized in that the holding portion (4) facing inside (15) of the hook (14) is at least 50% formed by the insert body (3). Gripper (1) according to one of the preceding claims, characterized in that the stop means (6) on the base body (2) in the guide portion (5) in the end region in the longitudinal direction in the direction away from the holding portion (4) is arranged. Gripper (1) according to one of the preceding claims, characterized characterized in that the distance in the longitudinal direction (L) of the stop means (6) from the end of the guide portion (5) towards the holding portion (4) is at least twice as long as the distance in the longitudinal direction of the stop means (6) from the holding portion (4) opposite end of the guide portion (5) of the gripper (1). Gripper (1) according to one of the preceding claims, characterized in that the stop means (6) fixed to the base body (2) and the abutment means (7) is fixedly arranged on the insert body (3). Gripper (1) according to one of the preceding claims, characterized in that the abutment means (6) comprises a stop surface element (8) having a surface perpendicular (9) in the longitudinal direction (L) to the end remote from the holding portion of the guide portion (5) of the gripper (1 ), and the abutment means (7) on the insert body (6) arranged contact surface element (10) having a surface perpendicular (11) in the longitudinal direction (L) to the holding section (2), and that the two surface elements (8, 10) are arranged adjacent to each other. Gripper (1) according to one of the preceding claims, characterized in that the stop means (6) is formed by a projection (12) on the base (2) - or insert body (3) and the abutment means (7) is formed as a recess ( 13) on the insert (3) - or basic body (2). Gripper (1) according to claim 8, characterized in that the projection (12) is formed integrally with the base (2) - or insert body (3). Gripper (1) according to claim 8, characterized in that the projection (12) is formed by an additional component. Gripper (1) according to one of the preceding claims, characterized in that the base body (2) and the insert body (3) in a width direction (B) do not overlap. Gripper (1) according to one of the preceding claims, characterized in that between the base body (2) and insert body (3) an adhesive, in particular a solder is arranged. Gripper (1) according to one of the preceding claims, characterized in that the insert body (3) comprises hard metal. Gripper (1) according to one of the preceding claims, characterized in that the base body (2) comprises a tool steel.

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