WO2008014756A1

WO2008014756A1 - Gripping arrangement

Info

Publication number: WO2008014756A1
Application number: PCT/DE2007/001310
Authority: WO
Inventors: Steffen Hailer
Original assignee: Nelson Stud Welding Inc.
Priority date: 2006-08-01
Filing date: 2007-07-24
Publication date: 2008-02-07
Also published as: DE202006011893U1

Abstract

The invention relates to a gripping arrangement (1) for accommodating welding studs (2), a) having a jaw chuck (4) arranged on a holder (3) and intended for accommodating a number of jaw elements, b) wherein the jaw elements are mounted such as to be displaceable radially in the direction of a centre axis A of the chuck (4), and c) wherein each jaw element is connected to a gripper finger (5a, 5b, 5c...) or is formed in one piece with the latter in order to grip the welding stud (2) between the free gripping ends (6a, 6b, 6c) of the gripping fingers (5a, 5b, 5c...) during a gripping movement by radial displacement of the jaw elements towards the centre axis A of the jaw chuck (4), wherein d) the gripping fingers (5a, 5b, 5c...) are designed in such a way that the free gripping ends (6a, 6b, 6c) move in the course of the gripping movement towards a gripping axis B which is different from the centre axis A of the jaw chuck (4).

Description

Greifanordmmg

The present invention relates to a gripping arrangement for receiving welding studs according to the preamble of claim 1.

It is known from welding technology to receive welding studs by means of gripping arrangements in order to supply them to the location of the intended weld. This can be done by means of welding robots, which carry a jaw chuck by means of a holder. The jaws guided by the jaw chuck are arranged displaceable radially in the direction of a central axis and can thereby hold or clamp a welding bolt provided or supplied in this axis. Subsequently, the bolt can be welded to a designated body, for which purpose the welding robot can move the jaw chuck with the bolt held therein into the welding area, if necessary.

Depending on the spatial configuration of the welding area and the constructive dimensions of the jaw chuck, it is sometimes difficult to achieve welding areas in the vicinity of interfering edges, since the spatial extent of the jaw chuck or the jaws guided therein hinder the approach of the weld stud to the intended weld, since they previously coincide with the interfering edge. A typical case is formed by two converging at a right angle surfaces when in the resulting throat area perpendicular to one or the other surface a bolt is to be welded.

Aufgäbe of the invention is therefore to provide a gripping arrangement largely using existing gripping components, which also allows the positioning or welding of bolts in the immediate vicinity of interference edges.

The object is achieved by a gripping arrangement by claim 1. The gripping arrangement according to the invention is based on the recognition that the gripping center, in which the welding stud is held, can be located outside the actual center axis, which is determined by the radial movement of the jaws or the jaw chuck itself. This can be achieved in that the jaw elements used in the jaw chuck are provided in a conventional manner with gripper fingers, but these gripping fingers are shaped so that the actual gripping center is not aligned with radial displacement of the jaw members with the center of the jaw chuck. Although the gripper fingers perform a radial movement towards the center of the jaw chuck out, but the gripper fingers gripping the gripping fingers are led out of the center axis of the jaw chuck and aligned so that they also in the radial movement of the jaw members in the direction of the center axis of the jaw chuck be moved toward each other, but in the direction of a not aligned with the center axis gripping axis. This will be made clear with reference to FIG. 1.

Such a gripping arrangement advantageously allows the holding or feeding of welding studs close to interfering edges, since the actual gripping axis is displaced from the center of the baking chuck to an edge region of the same or even beyond.

In a simplest embodiment, the gripping arrangement provides a jaw chuck arranged on a holder or an equivalent element for receiving a number of jaw elements. The jaw elements are displaceably mounted radially in the direction of a center axis of the chuck. Each jaw member is according to the invention connected to a gripper fingers or integrally formed therewith to grip the welding stud during a gripping movement by radial displacement of the jaw members to the center axis out between the free gripping ends of the gripper fingers. The gripper fingers are designed so that the free gripper ends to move in the context of the gripping movement on a gripping axis, which is different from the center axis of the jaw chuck. According to an advantageous embodiment of the invention, the gripper assembly is designed with their gripper fingers so that the gripping axis extends outside of the jaw chuck. This advantageously makes it possible to further approach the gripping axis to interfering edges and also permits immersion in depressions delimited on both sides, as shown in more detail in particular in FIG. In the same way as in the simplest embodiment described above, the radial clamping movement is hereby shifted in an inventive manner from the center axis of the jaw chuck, wherein in the last-mentioned case, the gripping axis even extends outside the body of the jaw chuck or its holder.

According to a further advantageous embodiment of the invention exactly three gripper fingers are provided for the gripping assembly. Thus, the welding stud can be well and safely received with little design effort, the gripper fingers can be performed sufficiently stable up to their gripping ends. Of course, the number of gripper fingers can also increase, which can be kept even better and more accurate with additional design effort of the welding bolt.

As already mentioned, the gripper fingers can each be formed in one piece with the jaw elements, which are mounted so as to be radially displaceable in the jaw chuck. However, an alternative embodiment provides that the gripper fingers are detachably connectable to the respective jaw members. This results in the advantage that the jaw chuck itself is also usable for conventional clamping or holding operations in the region of its center axis. By appropriately adapted gripper fingers, which would be attached to the jaw members, then possibly required only for a specific application, the inventive gripper assembly can be assembled without the jaw chuck should be replaced in itself. A particularly simple embodiment of a gripper arrangement with three gripper fingers provides that one of the gripper fingers extends substantially straight or symmetrically over the center axis of the jaw chuck in the direction of the new gripping axis, while the other two gripper fingers have substantially hook-shaped form. The particularly simple shape of the first gripper finger and the at least symmetrical possible formation of the other two gripper fingers allows a total cost and structurally simple design of the gripping assembly according to the invention. The meaningful hook-like shape of the two other gripper fingers results from the clamping movement required in the radial direction and is shown in more detail in FIGS. 2 and 3.

According to a further advantageous embodiment of the invention, the jaw chuck is pivotable relative to its holder. As a result, depending on the application, the jaw chuck can assume any desired rotational position relative to the holder, as a result of which the variety of applications of the gripping arrangement according to the invention is considerably increased. Thus, the gripping axis can be pivoted around, for example, 90 ° or 180 ° about the center axis of the jaw chuck in order to be able to weld in the vicinity of opposing or mutually angled arranged disturbing edges. The Schwerikvor- gang can be performed electrically, pneumatically or by other suitable drives. In particular, a pivotable jaw chuck also allows to receive the welding bolt in a first pivoting position in order subsequently to move it into a second pivoting position, in which the approach to the interfering edge is to follow (it is also conceivable, for example, to execute the necessary approximation or execution by the pivoting movement alone) Positioning the welding stud).

In this sense, according to a further advantageous embodiment of the invention, it is provided that the jaw chuck can be pivoted out of its welding position into a loading position in order to receive a welding stud in this position. Finally, a further embodiment of the invention advantageously provides that the welding stud can be raised in the direction of the gripping axis by feeding it from the rear side of the gripper fingers facing the lining. In this case, it is possible to position the welding bolt "from behind" between the gripping ends of the gripper fingers, whereupon they perform the gripping movement for holding the bolt. The bolt can be introduced so that it protrudes by a predetermined amount on the other side of the gripper fingers. With its free end of this protruding portion of the bolt can then be positioned and welded by appropriate positioning movement in the region of the Störkante, whereupon the grippers solve the clamping and release the bolt.

In this case, the bolt was quasi introduced from the back of the gripper fingers and leaves them after welding to the front. By a suitable device in the back of the gripper fingers thus continuously welding bolts can be supplied and clamped for the welding process without pivotal movement of the chuck between a loading and a welding position would be required (of course, the loading of the gripper fingers is also "from the front" possible so that the bolt leaves the clamping area after welding in the same direction from which it was previously used.

Further advantageous embodiments will become apparent from the dependent claims.

Hereinafter, some embodiments of the invention will be illustrated with reference to figures. Show

1 is a schematic side and top view of a first embodiment of the gripping arrangement,

Fig. 2 shows a second embodiment of the gripping assembly in a schematic side and top view and Fig. 3 is a schematic representation of different pivotal positions of the jaw chuck.

Fig. Ia shows a gripping assembly 1 according to the invention in the vicinity of a disturbing edge K, where a welding stud 2 is to be welded. For this purpose, the gripping arrangement 1 provides a holder 3 which carries a jaw chuck 4.

As can be seen in the plan view according to FIG. 1b, the jaw chuck has three jaw elements which at the same time form three gripper fingers 5a, 5b and 5c. The gripper fingers 5a, 5b and 5c are mounted so as to be radially displaceable in the direction of a center axis A of the jaw chuck, wherein the center axis A extends essentially centrally to the jaw chuck.

As can also be seen in Fig. Ib, the individual gripper fingers 5a, 5b and 5c are formed so that they run in the direction indicated by three arrows radial movement with their gripping ends on a gripping axis B, there to keep the pin 2 clamped. By the illustrated shape of the gripper fingers so the axis, in the direction of the clamping movement is carried out for holding the bolt, moved by a level with respect to the conventionally known center axis A. As can be seen in particular in Fig. Ia, the center axis A of the jaw chuck 4 is spaced so far from a disturbing edge K, that in the direction of this center axis a welding stud 2 could not be positioned in the manner shown. By the inventive displacement of the gripping axis B from the center of the jaw chuck 4 addition, however, the positioning shown in Fig. Ia is possible. The bolt 2 can be brought sufficiently close to the Störkante K in the desired manner and weld there. In this case, the gripping axis B still passes through the body of the jaw chuck 4, since the distance to the center axis A is completely sufficient for the positioning shown. In the illustrations according to FIGS. 2a and 2b, on the other hand, the gripping axis B lies outside the body of the jaw chuck 4. The associated gripper fingers 5a, 5b and 5c according to FIG. 2b are designed to be correspondingly longer in order to ensure the spacing between the axes A and B. , FIG. 2 b again shows that with radial movement of the gripper fingers 5 a, 5 b and 5 c in the direction of the center axis A of the jaw chuck 4, the gripping end 6 a, 6 b and 6 c formed on each gripper finger converges in the direction of the gripping axis B to the bolt 2 to clamp there accordingly.

Due to the greater spacing of the axes A and B to each other, there are further advantages, as will be explained with reference to FIG. 3c. There it can be seen that the not further inscribed gripper fingers protrude with the clamped by them welding pin 2 in a U-shaped formed Störkante to weld there the bolt. This would not be possible if the gripping axis B still passed through the body of the jaw chuck 4.

A further significant advantage of this embodiment is that the welding stud 2 can be fed into the clamping area from the rear side of the gripper fingers facing the jaw chuck 4, in order to leave the latter to the front, following the welding. The continuous provision of new welding studs is thus considerably simplified.

In Fig. 3a and 3b, the jaw chuck 4 is shown in two different positions relative to the holder 3. Fig. 3a shows the chuck 4 in a loading position I, in which welding studs, not shown, the clamping area along the gripping axis B can be supplied. Alternatively, the entire assembly could be moved with its orientation I in a Aufhahmebereich to be supplied there with a welding stud or actively absorb such. In Fig. 3b, the jaw chuck 4 is pivoted relative to the position I by 90 ° in a welding position II, in which the actual welding is to take place.

A feeding device, not shown, could therefore provide welding studs in the region of the gripping axis B according to position I, whereas the actual welding process takes place after pivoting of the baking chuck 4 into the welding position II, where the feeding device interferes less, for example.

Claims

claims

1. gripping arrangement (1) for receiving welding studs (2),

a) with a jaw chuck (4) arranged on a holder (3) for receiving a number of jaw elements,

b) wherein the jaw members are slidably mounted radially in the direction of a center axis (A) of the chuck (4), and

c) wherein each jaw member with a gripper finger (5a, 5b, 5c.) Connected or integrally formed therewith in a gripping movement by radial displacement of the jaw members to the center axis (A) of the jaw chuck (4) out between the free gripping ends (6a , 6b, 6c) of the gripper fingers (5a, 5b, 5c.) To grip the welding stud (2),

characterized,

d) that the gripper fingers (5a, 5b, 5c.) Are formed so that the free gripping ends (6a, 6b, 6c) move in the context of gripping movement on a gripping axis (B), which from the center axis (A) of Jaw chucks (4) is different.

2. Gripping arrangement according to claim 1, characterized in that the gripping axis (B) outside of the baking chuck (4).

3. Gripping arrangement according to one of the preceding claims, characterized in that three jaw chuck or gripper fingers (5a, 5b, 5c) are provided.

4. gripper assembly according to the preceding claim, characterized in that a Greiferfmger (5a) extends substantially straight or symmetrical about the center axis (A) of the chuck (4) away in the direction of the gripping axis (B), while the other two gripper fingers (5b, 5c) have hook-like shape.

5. Gripping arrangement according to one of the preceding claims, characterized in that the jaw chuck (4) relative to the holder (3) is pivotable.

6. gripper assembly according to the preceding claim, characterized in that the jaw chuck (4) from a welding position (II) in a loading position (I) is pivotable to receive in this position (I) a welding bolt (2).

7. Gripping arrangement according to one of the preceding claims, characterized in that the welding bolt (2) by feeding from the lining (4) facing the back of the gripper fingers (5a, 5b, 5c) in the direction of the gripping axis (B) is receivable.