EP0494570B1 - Method for inserting wires one by one in a clamp for retaining a group of wires, and gripper for carrying out this procedure - Google Patents

Description

The present invention relates to a method for inserting wires one by one into a clamp for holding a group of wires. It also relates to a gripper intended for the implementation of this method.

The invention relates more particularly to the technical sector of the construction of automatic wiring machines.

Patent FR-A-2,619,258 (Claude RICARD) describes in particular a wiring machine in which a connection piece is crimped, at the end of the chain, on the ends of a group of several conductive wires.

This machine can use, in one embodiment, clamps for holding this group of wires, which are particularly well suited for this use, and which are described in this document FR-A-2,619,258 with reference to its Figures 4 and 5.

The shape of a holding clamp of this type is shown diagrammatically in Figures 4 and 3 attached, which correspond respectively to Figures 4 and 5 of the aforementioned document FR-A-2,619,258. This particular conformation is, for the record, the following:

This holding clip has two pairs of spouts 14 which are held in the closed position by return springs 15, and it also has a piston 10 which is placed between the two pairs of spouts 14 and which is pushed up by a spring. 13. The upper face of this piston 10 has a flared notch 11.

The internal edge of each spout 14 has a ramp (indicated by arrows in FIG. 4) descending towards the center and, immediately below this ramp, a concave notch 11.

In Figures 4 and 3, a single wire is shown trapped by the retaining clip but, of course, this clamp is able to hold together a whole group of wires, as shown in Figure 4 of the aforementioned document FR-A-2,619,258. This Figure 4 shows a group of wires in place in the clamp, as well as another wire ready to join the others by simple pushing of this wire from top to bottom, in order to force the opening of the four beaks of the clamp. .

It is stated in this document FR-A-2.619.258, that the wires are placed one after the other in such a clamp by means of a manipulator referenced 12.

Such a manipulator must be equipped with a gripper capable of grasping each wire at two points and, this wire being well tensioned between these two points, then pushing it into the descending ramps of each pair of jaws of the holding clamp , to force these beaks to open and let the wire pass, then to close again on the latter, which then joins the group of wires already trapped in this holding part.

In this document, this manipulator and this clamp are not described in detail, because such elements are commercially available and are then quite capable of ensuring the implementation of this invention.

• . S'il y a déjà des fils dans la pince de maintien, on constate que ces fils ne sont pas correctement maintenus pendant la mise en place d'un nouveau fil.
• . Si le nouveau fil qui est mis en place est un fil fragile, par exemple de petite section, on constate une déformation de ce fil dûe au fait que la partie de ce fil qui est tendue entre ses deux points de préhension doit forcer sur le piston 10 pour le repousser vers le bas afin de dégager une place dans le faisceau de fils déjà emprisonnés dans cette pince de maintien.

The use of these conventional grippers nevertheless has drawbacks which affect the reliability of the device:

• . If there are already wires in the holding clamp, it can be seen that these wires are not properly held during the installation of a new wire.
• . If the new wire which is put in place is a fragile wire, for example of small section, there is a deformation of this wire due to the fact that the part of this wire which is stretched between its two gripping points must force on the piston 10 to push it down in order to free a place in the bundle of wires already trapped in this clamp.

These faults degrade the quality of the finished product, and even cause operating anomalies which make it necessary to interrupt the operation of the wiring machines.

• . de procurer des moyens permettant de maintenir correctement les fils se trouvant déjà en place dans la pince de maintien durant la mise en place d'un nouveau fil dans cette pince;
• . de procurer des moyens qui permettent de travailler aussi les fils fragiles, dans ces machines de câblage automatique;
• . et finalement d'améliorer la capacité de traitement et la fiabilité des machines de câblage automatique qui utilisent des pinces de maintien par exemple du type précité.

The invention aims to remedy these drawbacks, and therefore has for objectives:

• . to provide means making it possible to correctly maintain the wires already in place in the holding clamp during the placement of a new wire in this clamp;
• . to provide means which also make it possible to work the fragile wires in these automatic wiring machines;
• . and finally to improve the processing capacity and the reliability of automatic wiring machines which use clamps for example of the aforementioned type.

To this end, the invention relates to a method according to claim 1 and to a gripper for the implementation of this method, according to claim 3.

In any case, the invention will be well understood, and its advantages and other characteristics will emerge during the following description of an exemplary embodiment, with reference to the appended schematic drawing in which:

Figures 1 and 2 show a gripper, for the establishment of one or more wires in a holding clamp, in the process of placing a wire in a holding clamp, according to a side view and according to a partial section in elevation.

Figures 3 and 4, already described above, show this holding clamp, of known type, having means for gripping and holding one or more wires, in a side view and in a partial section in elevation.

According to the embodiment of Figures 1 and 2, the gripper is fixed by a pin 1 to a manipulator capable of performing the wire transfers, this manipulator being of known type.

A yoke 2 supported by the axis 1 carries the two jaws 4 and 5, of each of the two pairs of jaws, one pair being spaced from the other pair, with which this gripper is equipped.

These jaws can rotate around axes 3 and they are opened or closed by the action of a jack 6.

These jaws 4, 5 are coupled by two toothed sectors 7 in order to ensure the symmetry of their movements.

The jaws hold the wire to be inserted 8 at their ends and the portion of this wire which is between the jaws is kept tight between the two pairs of jaws.

This stretched wire portion is further maintained by support means 9 carried by the gripper.

These support means are produced by a pushing finger 9 which is fixed on the yoke 2 and which is positioned between the two pairs of jaws of the gripper.

According to Figures 1 and 2 the gripping pliers therefore comprises a pushing finger 9 which can engage between the two pairs 14 of beaks of the holding clamp and which supports the wire during the engagement of the latter in a clamp, and which temporarily holds it during the withdrawal phase.

When the wire is inserted into a clamp, this wire is held, inter alia, by the finger 9 which supports the stretched portion of the above-mentioned wire and which then pushes the piston 10 against the force of the spring 13.

At the end of the descent stroke, the lower part 12 of the finger 9, which is the active face of said support means, is at the same level as the internal shape detail 11 of the spouts 14 which itself defines the upper limit level of the wires held in the holding clip.

The finger 9, comprises, at its lower part in contact with the wire, a shape detail 12 for retaining said portion of wire and whose profile has a "V" shape or a concave shape.

Preferably, the pushing finger 9 is totally or partially made of an elastic material so that this finger remains in contact with the inserted wire 8 longer.

In the same way, according to another possible embodiment, it slides slightly along its longitudinal axis Z′Z, while being pushed towards the piston 10 by a spring, or other elastic means (not shown), which is more flexible than spring 13.

If the clamp is produced by a tangle of beaks or if the clamp has details of shape obstructing the movement of the finger 9, this finger is advantageously cut to slip between these beaks and these shape details, and it does not then support the wire tensed 8 only at certain points.

Thus the wire to be inserted 8 and the various wires 16 already present in the clamp are then temporarily held by the finger 9.

In particular when the spouts 14 are forced to open by the wire 8 to be put in place, the wire 16 or the other wires already inserted, like also the one being inserted 8, are held by compression between the piston 10, pushed towards finger 9 by spring 13, and between this finger 9.

These wires are also compressed and held by shearing between the edges 10a of the piston 10 and the edges 11 of the spouts 14 pushed back into the closed position by the springs 15.

Note that the positioning action can be carried out in the same way regardless of the number of wires already in place in the clamp. The cavity formed by the profile 11 of the spouts and the profile 10a of the piston adapts to the volume of the wires which it keeps compressed.

As during the insertion of a wire, it is the wire, itself well supported by the finger 9, which forces the spouts 14 to open, these spouts only open to let it pass and the already present sons can not escape.

In this case of holding forceps, the upper limit level of the wires held in place is fixed due to the design of the forceps. But with pliers for which this is not the case, the present invention retains its utility at least for fragile wires. The manipulator stroke is managed according to the variation of said limit level of the wires maintained.

Claims (7)

1. A process for inserting wires (8) one by one into a clamp (14,10) for maintaining a group of wires (8,16), characterised in that, during the insertion:

   . a portion of that wire to be inserted is held quite taut between two pairs of jaws (4,5) of another clamp, termed gripping clamp;

   . this portion of wire, which is taut between these two pairs of jaws (4,5), is supported with the aid of support means (9) which are borne by this gripping clamp, so as to counteract, during the insertion of this portion of wire into the maintaining clamp (14, 10), the counter-thrust reaction which would otherwise have a tendency to deform or even to damage this portion of wire.
2. The process according to Claim 1, characterised in that, during the fitting of a wire (8), into a maintaining clamp (14,10), the gripping clamp (1 to 7) is brought closer to this maintaining clamp (14,10) so that the active face (12) of the said support means (9) comes to the upper limit level of the maintained wires (6,8).
3. A gripping clamp for implementation of the process according to Claim 1 or Claim 2, this clamp comprising two pairs of jaws (4,5) adapted to catch, and to maintain quite taut, a portion of the wire (8) to be inserted into the maintaining clamp (14,10), characterised in that it further comprises a thrust finger (9) which is placed between these two pairs of jaws (4,5) and which supports this taut portion of wire (8) during the engagement of the latter in the maintaining clamp (14,10), and which moreover transiently maintains this wire (8) in place during the phase of withdrawal of the gripping clamp.
4. The clamp according to Claim 3, characterised in that the said finger (9) comprises at its lower part in contact with the wire (8) a form detail (12) the profile of which has a "V" shape or a concave shape.
5. The clamp according to Claim 3 or Claim 4, characterised in that the thrust finger (9) is totally or partially constructed in a resilient material.
6. The gripping clamp according to Claim 3 or Claim 4, characterised in that the thrust finger (9) is mounted sliding along its longitudinal axis (Z'Z) while being pushed by a spring, or other resilient means, towards the maintaining clamp.
7. The gripping clamp according to any of Claims 3 to 6, for the case of maintaining clamps (14,10), produced by criss-crossing catches (14) or clamps comprising form details hindering the movement of the finger (9), characterised in that the said finger (9), is cut away so as to slide between the said catches (14) and the said form details and so that it supports the wire (8) at some points only.

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