Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
  • H01H11/0056—Apparatus or processes specially adapted for the manufacture of electric switches comprising a successive blank-stamping, insert-moulding and severing operation

Definitions

• the invention relates to a contact unit, in particular for electrical switches, with a lead frame made of electrically conductive material, in which the lead tracks representing the electrical current paths are connected via webs and connecting contacts projecting from the die plane are provided, the space between the lead tracks being smaller is the length of a connector.
• Such contact units for electrical switches are known. 1 to 3, a lead frame of such a contact unit is shown. So that the contact unit and thus the switch are given a compact structure, the punched tracks representing the current paths are closely arranged to one another. On the lead frame there are also the connection contacts which are connected to the current paths in the interior of the switch. In order to maintain the compact structure also for the area of the connection contacts and to be able to use commercially available compact connection plugs which accommodate a plurality of connection contacts, the connection contacts are always in a predetermined narrow grid with respect to one another. As can be seen from FIG. 1, the space between the Punching paths are not sufficient to connect the connecting contacts in one piece to the lead frame. To maintain the narrow grid spacing, two techniques are usually used.
• a right and a left partial punched grid are produced with bent connection contacts present on the partial punched grids.
• the punching webs are connected to at least one contact plate overlapping the ends of the punching webs of the partial punching grid, whereby a one-part punched grid is produced.
• a large, continuous lead frame is produced.
• the connection contacts are not yet present on this lead frame, since the distance between the punch webs is not sufficient for the one-piece formation of the connection contacts on the lead frame.
• the connecting plugs are produced with a contact surface for attachment to the lead frame.
• the connector is usually connected to the lead frame by welding or riveting. Every connection point has to meet high quality requirements. On the one hand, an adequate electrical connection must be ensured, which in turn requires a high level of cleanliness of the parts before connection. On the other hand, the connection must also have a mechanically sufficient holding force.
• the invention has for its object to provide a contact unit of the type mentioned, which has a compact structure with a one-piece design, is inexpensive to manufacture and meets the highest quality requirements.
• connection contacts are formed in one piece with the lead frame, and the lead frame has at least one loop lying in the longitudinal direction of the connection contacts, which bends the connection contacts out of the punching plane of the lead frame and spacing the connection contacts allows a given grid dimension.
• the leadframe with the connection contacts can be produced as a one-piece part in a cost-effective manner while maintaining a predetermined, narrow grid dimension while at the same time meeting the highest quality requirements. No additional work steps are required.
• the elongated length of the loop corresponds to the length of the connecting contacts bent out of the lead frame and the width of a free punching between the free end of the connecting contacts and opposite regions of the lead frame. ters in the longitudinal direction of the loop taking into account the bending correction factor.
• connection contacts lying opposite, which can be bent out of the lead frame at right angles and can be brought to the desired grid size by bending the loop.
• connection contacts can be arranged directly opposite one another, i.e. the connection contacts do not have to be offset from one another.
• At least two punched tracks spaced apart in the lead frame and running parallel to one another each have a loop. This gives the lead frame a stiff and firm structure, which enables easier handling during assembly. Installation errors are avoided by introducing the loop differently, offset or opposite.
• At least one contact strip runs transversely to the alignment of the connection contacts and serves as a contact point on the punched tracks after the punching.
• the contact strips lie as an inlay or as a toplay on the punched strip in one direction. Since different electrical requirements occur in the switch or on a connection contact, it is necessary to meet these requirements by the presence of a specific contact material. However, in order not to have to apply too many contact strips, which also incur costs, the contact point is expediently brought to the desired position by at least one loop in the punched track of the connecting contact.
• connection contacts have the same length after the positioning of the contact points
• connection contacts embedded in the lead frame are expediently of different lengths. After positioning, the are Connection contacts of the same length and the bend can be made via a bending edge.
• connection contacts of the same length For example, in terms of tool technology, it is necessary to make thin cutting dies coherent for reinforcement, which leads to an offset of the cutting edges.
• the connection contacts of different lengths are therefore preferably given the same length by a loop.
• a punched track has at least two loops, through which at least one contact point and / or a connection contact is positioned.
• the loops in the lead frame are present on the side opposite the connection contacts. This results in the loops being accommodated in the interior of the switch, as a result of which no additional measures are necessary to protect the loops from damage or contact.
• the lead frame representing the contact unit still has to be separated into the individual current paths, the lead frames realizing the current paths being electrically separate from one another must be fixed in isolation.
• the handling of the contact unit should take place as part for cost reasons. Therefore, according to a development of the invention, the lead frame is fastened on an insulating plastic part, the webs of the lead frame being separated between the punched tracks after the lead frame has been fastened.
• the lead frame is attached to the plastic part by extrusion coating with plastic, the contact surfaces of the lead frame and the connecting contacts not being extrusion-coated, and the encapsulation being carried out in a tool producing the plastic part.
• the lead frame is held in an electrically insulated manner, and when the extrusion coating is carried out, the switch part, which is required anyway, is simultaneously produced, for example a base.
• 1 is a plan view of a lead frame of a known contact unit
• FIG. 2 is a side view of the lead frame and FIG. 1 in the direction of arrow II, 3 shows an alternative embodiment of the representation according to FIG. 2,
• FIG. 4 shows a plan view of a lead frame for producing a lead frame of a contact unit according to the invention
• FIG. 5 shows a side view of a contact unit made from the lead frame in the direction of arrow V according to FIG. 4,
• FIG. 6 is a view of the contact unit of FIG. 5 in the direction of arrow VI,
• Fig. 8 is a side view of the contact unit according to
• FIG. 9 is a plan view of a lead frame with contact strips for the production of a according to the invention.
• FIG. 10 is a plan view of the lead frame according to FIG. 9 after introducing small loops
• FIG. 11 is a side view of the lead frame according to Figure 10 in the direction of arrow XI
• Fig. 12 is a plan view of the contact unit made of the lead frame shown in FIG. 10 and
• FIG. 13 is a side view in the direction of arrow XIII according to FIG. 12.
• connection unit 1 which, in its large extent, consists of a substantially rectangular lead frame 2.
• connection contacts 3 protrude from the plane of the lead frame 2.
• the punched webs 4 represent the current paths.
• the webs 4 are connected by webs 5 between the punched webs 4 and thus form the lead frame 2.
• diagonally opposite holding bores 12 are inserted, with which the lead frame 2 is positioned.
• large openings 13 are provided in the lead frame 2, which are used for other functions within an electrical switch.
• the contact unit 1 according to FIG. 1 has a total of seven connection contacts 3. In each case three connection contacts 3 are arranged opposite one another.
• connection contacts 3 are in a grid to each other.
• the clearance 14 in the plane of the lead frame 2 between the connection contacts 3 is by no means wide enough to be able to accommodate the length of the bent connection contacts 3.
• the contact unit 1 according to FIG. 2 consists of a right lead frame 6 and a left leadframe 7 on which the connecting contacts 3 are present and bent in one piece.
• the right lead frame 6 is connected to the left lead frame 7 via the punched tracks 4a, 4b and 4c on the longitudinal sides 8.
• the punch webs 4a, 4b and 4c corresponding contact plates 9, which are welded onto the top 10 of the punched grid 6, 7, the punched grid 6, 7 are connected to the contact unit 1.
• FIG. 3 An alternative to this is shown in FIG. 3.
• the contact unit 1 consists of a flat continuous lead frame 2, on the underside 11 of which angled connection contacts 3 are welded.
• a lead frame 2 for a contact unit 1 according to the invention is shown in FIG.
• the lead frame 2 also has the openings 13 and holding bores 12.
• the connection contacts 3 are still folded, which are integrally connected to the lead frame 2. Between the free end of the connection contacts 3 there is still sufficient space for the punching 14.
• the outer areas of the lead frame 2, in which the holding bore 12 and the openings 13 are provided, are identical to the lead frame 2 according to the prior art. Only the punched webs 4a, 4b and 4c provided on the long sides 8 are longer, which means that the punched grid 2 has a greater length.
• FIGS. 5 and 6 show the corresponding side views of the constructions produced from the lead frame 2 according to FIG. clock unit 1.
• the connecting contacts 3 are bent out of the plane of the lead frame 2 by 90 ° on the underside 11. So that the connection contacts 3 can be brought to the required grid dimension, the punched strips 4a, 4b and 4c arranged on the longitudinal sides 8 each have a U-shaped loop 15.
• the bending direction of the loop 15 lies in the longitudinal direction of the connection contacts 3, and the loop 15, or the punched strips 4a, 4b and 4c, are carried out so long that a spacing of the connection contacts 3 to the predetermined grid size is made possible.
• the legs 16 of the loop 15 run at an acute angle to one another, whereby a bending punch forming the loop 15 can be easily immersed and pulled out.
• the length of the loop 15 is equal to the length of the bent out of the lead frame 2 contacts 3 plus the width of the punch 14, which is between the free end of the contact 3 and the opposite part of the lead frame 2 is present. In this case, only the width of the relief 14 in the longitudinal direction or the bending direction of the loop 15 is taken into account. The bending correction factor is also taken into account when calculating the stretched length of the loop 15.
• connection contacts 3 lie opposite each other in the bending direction of the loop 15 in the lead frame 2, and the bending edge 17 of the connecting contacts 3 runs perpendicular to the longitudinal sides 8 of the lead frame 2.
• the part opposite the free end of the connecting contacts 3 is always taken into account.
• two free ends of connection contacts 3 lie opposite one another. The clearance 14 is thus the area between the free ends of the contacts 3.
• the contact strip 18 is introduced in the manner of an inlay, as can be seen from FIGS. 11 and 13.
• a toplay material can also be used in which the contact material is applied to the top 10 of the lead frame 2. Both rolled strips and an electroplated thin strip layer can be used. After the punching, only contact points 19 remain on the punched tracks 4 of the punched grid 2 or the contact unit 1 of the contact strips 18 (see FIGS. 9, 10 and 12).
• connection contacts 3 embedded in the lead frame 2 have a different length. However, the contact points 19 are still in the area of the previously existing contact strip 18. Since different electrical requirements are present on the top 10 of the contact unit 1, these requirements should be taken into account with a contact point 19. In order to avoid that too many contact strips 18 are required, the contact point 19 in the lead frame 2 or the contact unit 1 is displaced by introducing a loop 15. This is clearly evident from FIG. 10, in which the contact points 19 have been moved out of the area of the contact loops 18 by introducing three loops 15. Thus, on the one hand, the fact that different contact points 19 are required on the top side 10 is taken into account, and on the other hand that 3 different contact points 19 are necessary on the connection contacts. So that the connection contacts 3 have the same length despite everything, the loops 15 in the connection contact feet 20 are designed such that these requirements are met.
• three loops 15 are incorporated in the punched tracks 4a and 4b.
• the loops 15 are located at different lengths of the respective punched web 4a or 4b and have a different depth, but the legs 16 of the loops 15 run at an acute angle to one another. This makes it possible for all the contact points 19 on the punched tracks 4 to have a position spaced apart from the original contact strip 18.
• FIG. 11 and 13 represent side views of contact units 1.
• the loops 15, which are rectangular in shape, are only bent in the direction of the underside 11 of the contact unit 1.
• This state represents an intermediate state in which the connection contacts 3 have not yet been bent out of the plane of the lead frame 2.
• the connection contacts 3 are then bent out and the further loops 15 are added.
• a contact unit 1 similar to that in FIG. 11 is shown in FIG. 13, which has already gone through this working step and thus carries the loops 15 on the upper side 10. 7 and 8, the contact unit 1 is already attached to a plastic part 21.
• the plastic part 21 is the base of a switch which is held in a housing, not shown, via clip lugs 22.
• the contact unit 1 is fastened in the electrically insulating plastic part 21 by injection molding with plastic in a tool, the contact unit 1 being adjusted in its holding bores 12.
• the base receives its usage form directly.
• the contact surfaces 23 and the connecting contacts 3 of the contact unit 1 are not overmolded.
• the connecting contacts 3 protrude from the underside 24 of the plastic part 21 and are surrounded by a plug collar 25 in a protective manner.
• the loops 15 which are bent on the long sides 8 of the contact unit 1 in the direction of the upper side 10 are also extrusion-coated and thus protected.
• the punched webs 4 are separated into their individual current paths after being fastened.
• the webs 5 are punched out at separating points 27.
• latching links 26 are formed in the plastic part 21, which interact with latching elements, not shown, held in the switch.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture Of Switches (AREA)
• Contacts (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7758288

Family Applications (1)

Country Status (4)

Families Citing this family (3)

Citations (3)

Family Cites Families (5)

• 1995
  • 1995-03-31 DE DE19511877A patent/DE19511877A1/de not_active Withdrawn
• 1996
  • 1996-03-27 DE DE59602630T patent/DE59602630D1/de not_active Expired - Lifetime
  • 1996-03-27 ES ES96909017T patent/ES2136394T3/es not_active Expired - Lifetime
  • 1996-03-27 EP EP96909017A patent/EP0818047B1/de not_active Expired - Lifetime
  • 1996-03-27 WO PCT/DE1996/000607 patent/WO1996030918A1/de active IP Right Grant

Patent Citations (3)

Also Published As

Similar Documents

Legal Events