EP0497766B1 - Device for producing a contact device, contact device and the use thereof - Google Patents

Abstract

The invention concerns the establishment of an electrical connection for the supply of a switching current between one end (2) of a connector wire (1) and a contact piece (7) mounted on a contact support (3), contact being established through a hole (4) in the contact support (3). In order to simplify production of this kind of contact, the invention calls for one end (2) of the wire to be joined to an extension (10) formed by a stamping procedure in which the hole (4) in the contact support (3) is utilized as a tool to shape the extension (10). This ensures that the dimensions of the extension (10) match in optimum fashion the dimensions of the hole (4). In addition, the fact that the extension (10) is formed in the hole (4) itself makes it unnecessary for the end of the wire carrying the extension (10) to be positioned relative to the contact support (3) or the hole (4) in it. The process is of particular use in the production of connections for switchgear and relays.

Description

The invention relates to a method for producing a contact device, in which an end section of an electrical connecting line is brought up to a first flat side of a sheet-shaped contact carrier, is passed through a recess in the contact carrier and is electrically conductively connected to a contact piece on the opposite second flat side of the contact carrier. The invention also relates to a correspondingly designed contact device and to the use of this contact device.

From the German utility model 81 09 089 a contact device is already known, which is produced in the manner mentioned above. There, one end of an electrical connecting line for supplying a switching current from one side of the contact carrier is connected in an electrically conductive manner to a contact piece through a recess in the contact carrier designed as an opening on the other side of the contact carrier. The one end of the electrical connection line or the recess of the contact carrier must be exactly matched to one another in terms of its dimensions in order to allow the one end to be passed through the recess without play and yet as easily as possible. In particular in the production of relatively small contact devices, the positioning of one end relative to the recess of the contact carrier is difficult and causes additional manufacturing costs which are reflected in the manufacturing costs. If the dimensions of the recess of the contact carrier change, be it as a result of changes in construction or as a result of tool wear, it is necessary to adapt the tool that produces the one end.

A contact arrangement is also known from EP-A-0 167 668, in which a connecting line in the form of a stranded wire is connected directly to a contact piece. This is particularly the problem that the contact carrier in the form of a center contact spring should be provided on both sides with a contact piece. To weld the connecting wire, it is therefore proposed to let one of the contact pieces protrude beyond the width of the contact spring end and to weld the wire to the protruding part. The second contact piece is designed there as a contact rivet with a round cross-section, which is connected to the first-mentioned elongated contact piece with a corresponding extension through a hole in the spring. These round contact pieces require a higher manufacturing effort; there is also the risk that the two contiguous contact pieces are rotated by tensile forces on the wire in the hole of the contact spring, which would change the position of the elongated contact piece relative to its counter-contact element.

The object of the invention is to provide a method of the type mentioned and a corresponding contact device with the simplest and cheapest possible production, in particular a direct connection of a connecting line both with a single contact with the contact piece of the contact carrier and with a changeover contact with both contact pieces Center contact spring is possible and where inexpensive contact pieces can be used.

According to the invention the object is achieved with respect to the method in that the end section of the connecting line with a flat pressed longitudinal side is placed in parallel on the first flat side of the contact carrier with all-round coverage of the recess, that an extension perpendicular to the flat side through the recess of the connecting line from the end section Contact carrier is embossed and that during the stamping process, the contact carrier itself with the contour of the recess serves as a shaping tool.

Since the recess of the contact carrier is used as a shaping tool for the embossing process for producing the extension, the extension formed in this way is always exactly adapted to the dimensions of the recess of the contact carrier, even if they should vary during a production lot. Furthermore, changes in the geometry of the recess are possible in a wide range without incurring costs for changing a tool producing the extension. Another advantage of the method according to the invention is that after the embossing process the extension already reaches through the recess of the contact carrier without play and non-positively, and thus additional manufacturing steps for positioning the extension relative to the recess, for passing through and fixing the extension are omitted. It is also advantageous that no precisely pre-stamped contact rivets with a cross section adapted to the recess of the contact carrier have to be used. Inexpensive welding contacts can thus be found which are simply cut off and welded on from the strip.

In the method according to the invention, the inner circumferential walls of the recess in the contact carrier can run perpendicular to their flat sides, so that the extension likewise takes the form of a column with circumferential walls running perpendicular to the flat sides. An undercut or conical configuration of the bore in the contact carrier, as in the known fleece riveting of contact pieces, is not necessary here, since the contact piece is connected to the extension from the opposite side. With regard to the transport of the semifinished product created after the embossing process during the subsequent production steps, in particular up to the connection of the contact piece with the extension, it may be advantageous to connect the extension to the contact carrier after the embossing process. This can be done by a simple weld; however, other joining methods, for example gluing, are also conceivable. It can further be carried out in a post-embossing process such a further deformation of the extension that the extension expanded like a rivet head to form a positive connection outside the recess. The recess preferably has a non-circular cross section; A rotational cross-section of the extension in the recess is reliably prevented by, for example, an angular cross section. This advantageously avoids a relative movement or a slipping out of the extension to or from the recess of the contact carrier.

Furthermore, it is expedient that the end section of a connecting line designed as a strand is compacted in a plate-like manner before being placed on the contact carrier, the individual wires of the strand being welded, for example. In this way, a particularly exact geometry of the extension can be achieved because the compressed material of the connecting line can be better shaped. This is particularly advantageous if the extension is to protrude on the opposite second flat side.

It is particularly cost-effective if several contact devices are mass-produced and initially a coherent strand of connecting lines with alternating non-compressed and compressed conductor sections is produced, then a compressed section is placed on a contact carrier as the end section of a first connecting line and embossed into the recess and finally a protruding part is separated from the embossed section, which forms an initial section of a further connecting line. This greatly simplifies the handling of large quantities, because the connecting lines of several successive contact devices are still connected during the stamping process and therefore do not have to be transported as individual pieces.

According to the invention, a contact device with a contact carrier in the form of a leaf spring, which has a recess, is further arranged on a first flat side of the carrier Connecting line and a contact piece arranged on the second flat side of the carrier, which is electrically conductively connected to a section of the connecting line guided through the recess, in which the connecting line lies with a plate-shaped end section on the first flat side of the carrier, in which the plate-shaped End section an extension is embossed perpendicular to the flat side of the carrier, extends through the recess at least over the entire thickness of the carrier and is connected to the contact piece on the second flat side of the carrier. Preferably, the recess of the contact carrier as well as the extension of the connecting line have a non-circular cross section. In this way, a rotation of the extension and the contact pieces connected to the connecting line is reliably avoided, which is particularly important in the case of elongated welding contacts.

If, in addition, the surface of the end section of the connecting line facing away from the contact carrier is provided with a second contact piece, it is expedient that this plate-shaped end section decreases in a wedge shape in the direction of the free end of the carrier. The angular movement of the contact carrier, for example a contact spring connected to an armature, can thus be taken into account. If the corresponding mating contact elements are parallel to one another, this wedge-shaped arrangement of the contact pieces on the end section of the connecting line can ensure that the respective contact piece is also parallel to the mating contact element in the respective switching position.

• Figur 1 Bestandteile einer nach dem erfindungsgemäßen Verfahren herzustellenden Kontaktvorrichtung in ungefügtem Zustand;
• Figur 2 eine nach dem erfindungsgemäßen Verfahren hergestellte Kontaktvorrichtung im Schnitt;
• Figur 3 ein zur Durchführung des erfindungsgemäßen Verfahrens verwendetes Werkzeug;
• Figur 4 eine schematische Darstellung der Durchführung des erfindungsgemäßen Verfahrens in Form einer Serienfertigung und
• Figur 5 einen Kontaktträger als Mittelkontaktfeder im Längsschnitt mit keilförmig angeordneten Kontaktstücken.

The invention is explained below with reference to the drawing; show it

• Figure 1 components of a contact device to be produced according to the inventive method in the unassembled state;
• Figure 2 shows a contact device produced by the method according to the invention in section;
• FIG. 3 shows a tool used to carry out the method according to the invention;
• Figure 4 is a schematic representation of the implementation of the method according to the invention in the form of a series production and
• Figure 5 shows a contact carrier as a center contact spring in longitudinal section with wedge-shaped contact pieces.

FIG. 1 shows, as part of a contact device, an electrical connection line 1 in the form of a copper wire, which has an end section 2 compressed by means of a welding process. A contact carrier 3 of the contact device is provided with a recess 4. The recess 4 has a circular cross section reduced by one segment. In the course of a joining process by means of an embossing tool (not shown in FIG. 1), the end section 2 of the electrical connecting line 1 is guided to one flat side 3a of the contact carrier 3 in the direction of the arrows 5; in the same way, a contact piece 7 is guided to the opposite flat side 3b of the contact carrier 3, as indicated by arrows 6. In addition, a second contact piece 17 can be placed on the flat side 2b of the end section, as indicated by the arrows 15.

Figure 2 shows the components of the contact device according to Figure 1 after the stamping process in the joined state. One end 2 of the electrical connection line 1 now has an extension 10 which is stamped out of the flat side 2a perpendicular to the surface and which extends through the recess 4 of the contact carrier 3 and is welded on its end face 11 to the contact piece 7 to form an electrical connection 12. The circular cross section 4a of the recess 4 reduced by a segment 4b causes the extension 10 to be formed in the form of a cylinder with a corresponding flattening of its lateral surface during the stamping process. This prevents rotation of the extension 10 in the recess 4. The contact piece 7 is to improve the electrical conductivity of the connection 12 plated with a silver layer 13. The contact device created in this way can be part of a relay, for example, as is generally described in the German utility model 83 25 986 with its magnet system. The armature of the relay would be connected to the contact carrier 3 designed as a contact spring. It is also conceivable to use the contact device shown in FIG. 2 in an alternating contact arrangement, the contact piece 17 shown in dash-dotted lines in FIG. 2 being electrically conductively connected to the flat side 2b of the end section 2 of the electrical connection line 1 facing the extension 10. The welding surface formed by the side 2b is formed during the stamping process in such a way that a quality of the electrical connection to the contact piece 17 corresponding to the connection 12 is ensured.

FIG. 3 shows a tool which can be used to produce the contact device and which consists of an upper part in the form of a stamp 20 and of a receptacle 21 which interacts with this stamp. The plunger 20 can be moved in the vertical direction 22 and can be lowered with a pressure sufficient for the deformation, for example, of an electrical connecting line designed as a copper wire. Inserted into this tool are the end section 2 of the electrical connecting line 1 and at least with its recess 4 having the area of the contact carrier 3. The pressure generated by the stamp 20 causes the material of the end section 2 to pass through the recess 4 of the contact carrier 3 to form the Extension 10 shaped. The receptacle 21 has a slight depression 21a with a circular cross section, the diameter of which is roughly matched to the recess 4. If the recess 21a has a larger diameter than the recess 4 with an essentially circular cross section, the material of the end section 2 flows after the actual embossing process corresponding to the recess 21a, so that a rivet-like, form-fitting fixation of the extension 10 in the recess 4 is created . The extension formed in this way 10 extends over a plane 23 formed by the lower surface of the contact carrier 3 according to FIG. 3 and projects beyond the contact carrier 3 on this side. The receptacle 21 can simultaneously serve as a welding tool for producing a weld connection which fixes the extension 10 in the recess 4 to the contact carrier 3 by means of electrical resistance welding. In order to complete this arrangement to form a contact device according to FIG. 1 or 2, a contact piece 7 or 17 is applied on one side or on both sides in an electrically conductive manner to the extension 10 or to the side of the end section 2 of the electrical connecting line 1 facing away from the extension 10. With appropriate design of the stamp 20 or the receptacle 21, this can take place immediately after the stamping process.

FIG. 4 schematically shows a method for successively producing a plurality of contact devices (series production), a method step embossing 30 and a method step separating 31 being shown in detail as method steps. A plunger 32 can be moved up and down in the vertical direction 33 and forms a stamping tool according to FIG. 3 with a receptacle 34. The plunger 32 has a bevel 36 so that the electrical connecting line 1 can move away from the contact carrier 3 at a predeterminable angle 35 on. A strand 37 has alternately non-compressed sections 38a, 38b and compressed sections 39a, 39b. If necessary, after further workstations, the separating process step 31 follows in the course of series production, by means of which the compressed section 39a of the strand 37 is separated by a separating cutting edge 40. In this case, a first part 41 of the compressed section 39a is formed, which forms the end section 42 of an electrical connecting line 43 provided with the extension, which is formed completely when the immediately following compressed section 39b of the strand 37 is separated in the same way. A second part 44 of the compressed section 39a formed by the separation does not form an initial section 45 of a further electrical connecting line 46 shown previous contact device, which serves for the external connection of this electrical connection line 46.

FIG. 5 shows a modified embodiment of the contact device. The contact carrier 3 is shown in the form of a contact spring connected to an armature 8 in a side sectional view. In this case, the compressed end section 9 of the stranded wire 1 is tapered toward the free end, which is indicated by the exaggerated angle α. Correspondingly, the contact pieces 7 and 17 welded onto the extension 10 or onto the rear side 9b of this end section also form a slight angle to one another. This angle is matched to the angular movement of the armature 8 and, with customary dimensions and contact distances, is approximately in the order of magnitude of up to 5 °. This wedge-shaped configuration makes it possible for the respective contact piece to be approximately parallel to the associated mating contact element in each switching position. In the present example, the contact piece 7 is thus essentially parallel to the mating contact element 18. If the armature is pivoted into the second switching position, the contact spring assumes the position 3 ', while the contact piece 17 or 17' is now parallel to the mating contact element 19.

The described method can be used in a simple manner to create a contact device in which an extension of one end of an electrical connecting line is optimally matched to a recess in a contact carrier in that the recess itself serves as a tool for producing the extension. Already in the making, the extension is correctly inserted into the recess, positioned and positively connected to the contact carrier when the embossing tool (receptacle) is described above, and thus forms a structural unit that is easy to handle during the further manufacturing process.

Claims (10)

1. Process for manufacturing a contacting device in which an end section (2) of an electrical connecting line (1) is guided to a first flat side (3a) of a leaf-shaped contact support (3), led through a recess (4) of the contact support (3) and connected in an electrically conductive fashion to a contacting piece (7) on the opposite, second flat side (3b) of the contact support (3), characterised in that the end section (2) of the connecting line (1) is placed parallel with a pressed-flat longitudinal side (2a) on the first flat side (3a) of the contact support (3), covering the recess (4) on all sides, in that an extension (10) is stamped out of the end section (2) of the connecting line (1) perpendicularly to the flat side (3a) through the recess (4) of the contact support (3), and in that during the stamping process the contact support (3) itself serves as a shaping tool with the contour of the recess (4).
2. Process according to Claim 1, characterised in that the extension (10) is connected to the contact support (3) after the stamping process.
3. Process according to Claim 1 or 2, characterised in that the end section (2) of a connecting line (1) constructed as a stranded conductor is compressed in a plate shape before being applied to the contact support (3).
4. Process according to one of Claims 1 to 3, characterised in that the recess (4) in the contact support (1) is preformed with circumferential walls (4a) extending essentially perpendicularly to its flat sides (3a, 3b).
5. Process according to Claim 3 or 4, characterised in that, during a series production of contacting devices, a continuous length (37) of connecting lines with alternately non-compressed (38a, 38b) and compressed (39a, 39b) sections is initially manufactured, in that a compressed section (39b) is then placed as end section of a first connecting line (37) on a contact support (34) and stamped into the recess (4), and in that a protruding portion (44) is then cut off the stamped section (39a), which portion forms an initial section of a further connecting line (46).
6. Process according to one of Claims 3 to 5, characterised in that the free surface (2b) facing away from the contact support (3) is connected directly to a second contacting piece (17).
7. Contacting device having a contact support (3) in the form of a leaf spring which has a recess (4), a connecting line (1) arranged on a first flat side (3a) of the support (3) and a contacting piece (7) arranged on the second flat side (3b) of the support (3), which contacting piece is connected in an electrically conductive fashion to a section (10) of the connecting line led through the recess (4), characterised in that the connecting line (1) lies with a plate-shaped end section (2) on the first flat side (3a) of the support (3), in that an extension (10) is stamped out of the plate-shaped end section (2) perpendicularly to the flat side of the support (3), extends through the recess (4) at least over the entire thickness of the support (3) and is connected to the contacting piece (7) on the second flat side (3b) of the support.
8. Contacting device according to Claim 7, characterised in that the recess (4) of the support (3) and the extension (10) of the connecting line (1) have a cross-section (4a, 4b) which is non-round to the same degree.
9. Contacting device according to Claim 8, characterised in that the plate-shaped end section (2) of the connecting line (1) decreases in thickness in a wedge shape in the direction of the free end of the support (3).
10. Use of a contacting device according to one of Claims 7 to 9 in an electromagnetic relay, the contact support being connected as central contact spring to a change-over contact arrangement with a swivellable armature.

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