AN ELECTRICAL CONNECTOR AND AN ELECTRICAL TERMINAL

Abstract: The connector comprises an insulating housing (4) defining a cavity (12) for receiving an electrical terminal (17) and having wire receiving slots (16). The terminal comprises a pair of plates (18 and 20) joined by a bight (22). To connect the terminal (17) to a fine magnet wire (W), the terminal (17) is inserted into the cavity, the wire (W) is placed in the slots (16) to extend between the plates (18 and 20) of the terminal, and a clip (24) is pushed down an extension (26) of one (18) of the plates (18 and 20) to force the plates (18 and 20) together to compress the wire (W) between them. The other plate (20) has serrations (42) for piercing varnish insulation (V) on the wire (W).

Description: AN ELECTRICAL CONNECTOR AND AN ELECTRICAL TERMINAL This invention relates to an electrical connector and to an electrical terminal. There is described in GB-A-1,522,863, an electrical connector comprising an electrically insulating housing having walls defining a terminal receiving cavity, the housing having an open end and an opposite end, two opposed walls of the housing being formed with a wire receiving slot extending from said open end towards said opposite end and an electrical terminal comprising a pair of juxtaposed wire gripping plates connected in face to face relationship by a bight of the terminal material, the terminal being insertable into the cavity through said open end with the bight leading, to make electrical connection with a wire extending through said wire receiving slots. This known connector is used, for example, for connecting the magnet wire of an electric motor stator to an electrical lead. The plates are formed with slots into which the wire is forced as the terminal is inserted into the cavity. The wire is accordingly subjected to frictional wear by the edges of the slots. The present invention is intended to provide such a connector, and a terminal therefor, which is suitable for connecting a fine wire, for example of 0.2 mm to 0.05 mm in diameter, for example of a field coil of a small electric motor or solenoid, to an electrical lead. According to one aspect of the invention, an electrical connector as defined in the second paragraph of this specification, is characterized by a clip which is slidable along the plates and towards the bights, to drive the plates relatively towards each other to compress the wire between them, g following the insertion of the terminal into the cavity and the insertion of the wire through the wire receiving slots and between the plates. Thus, the wire is only engaged by the plates, in a .direction substantially at right angles to the ln longitudinal axis of the wire, so that the wire is not subjected to frictional engagement by the plates during the connecting operation. For guiding the clip in relation to the plates, one plate may be provided with an extension which . .. projects beyond the other plate in a direction away from the bight, said extension having embossed longitudinal edge portions which are engageable with guide portions of the clip. These guide portions of the clip may be in the form of opposed beads 20 projecting inwardly of the clip from end walls thereof so that each embossed edge portion of the extension is engageable with a rear wall of the clip and with one of said beads which extend in the insertion direction of the clip. In order to allow the clip to be pushed to a home 25 position about the plates, the clip may be provided with recesses extending from the leading edge thereof so as to receive the wire. For movement of a free portion of the other plate towards the one plate, the other plate may be bowed 30 towards the one plate, so as to be contiguous therewith at the crest of the bow to provide a pivotal axis for said other plate. In order to predetermine the extent to which the 35 clip can be slid along the plates, towards the bight, the cavity may have a reduced cross section first portion remote from the open end, for receiving the bight, and an enlarged cross section second portion for receiving the clip, a shoulder defined by the housing between the first and the second portions of the cavity serving to limit the movement of the clip towards the bight. In order to maintain the integrity of the connection between the wire and the terminal, the clip may have a projection which is engageable with the wall of the second portion of the cavity to secure the clip therein, the terminal having a projection in the vicinity of the bight, for engagement with a wall of the first portion of the cavity, to secure the terminal therein. Where the wire is a varnish insulated wire, as is usual in the case of magnet wires, at least one of the plates is provided with serrations facing the other plate, for piercing said insulation as the wire is compressed between the plates. According to another aspect of the invention, an electric terminal comprising a pair of juxtaposed wire gripping plates connected in face to face spaced relationship by a bight of the terminal material, the plates having free edges which face away from the bight and one of the plates having an extension pro- jecting away from the bight and beyond the other plate, is characterized in that the other plate is bowed towards the one plate in the vicinity of the bight, so as to be contiguous with the other plate at the crest of the bow, the other plate having serrations formed in its surface facing the one plate and extending from the free edge of the other plate towards the bight. For a better understanding of the invention and to show how it may be carried into effect, reference will now be made by way of example to the accompanying drawings in which: FIGURE 1 is an exploded, perspective view of an electrical connector for making connection with a fine magnet wire; FIGURE 2 is a perspective view, shown partly in section, of the connector when about to be connected to the magnet wire; FIGURE 3 is a similar view to that of Figure 2 , but showing the connector after it has been connected to the magnet wire; FIGURE 4 is an enlarged, mainly sectional view through the connector as shown in Figure 2; FIGURE 5 is an enlarged, mainly sectional view of the connector as shown in Figure 3; and FIGURE 6 is a view taken on the lines 6-6 of Figure 5. The connector which is generally referenced 2, comprises an insulating housing 4 having side walls 6, end walls 8, and a base wall 10 defining a terminal receiving cavity 12. The housing has an open end 14, the opposed end walls 8 of the housing each being formed with a wire receiving slot 16 extending from the open end 14 towards the base wall 10. A one piece electrical terminal 17 comprising a pair of juxtaposed wire gripping plates 18 and 20 connected in face to face spaced relationship by a bight 22 of the terminal material, is insertable into the cavity 12 through the open end 14 of the housing 4, with the bight 22 leading. A clip 24 is slidable along the plates 18 and 20, towards the bight 22, from the position in which the clip 24 is shown in Figures 2 and 4 and that in which it is shown in Figures 3, 5 and 6, to drive the plates 18 and 20 relatively towards each other to compress between them a fine magnet wire W, following the insertion of the terminal 17 into the cavity 12 and the subsequent insertion of the wire W into the wire receiving slots 16 and between the plates 18 and 20 as shown in Figure 2. The plate 18 has an extension 26 which projects beyond the plate 20 to provide a guide for the clip 24, which is first pushed over the extension 26 as shown in Figure 2 prior to the insertion of the terminal 17 into the cavity 12. A circular opening 27 in the extension 26 serves for receiving an electrical lead wire (not shown) to be soldered to the extension 26. A free end edge 29 of the extension 26 faces away from the bight 22. The extension 26 has embossed longitudinal edge portions 28 each of which is slidably engaged between a rear wall 34 of the clip 24 and a respective bead 30 which projects inwardly of the clip 24 from an end wall 32 thereof. The clip 24 has two rudimentary front walls 36 which are connected to the rear wall 34 by the side walls 32. The side walls 32 are formed with recesses in the form of blind slots 48, which are precisely aligned with one another for receiving the wire W as the clip 24 is moved from its Figures 2 and 4 to its Figures 3, 5 and 6 positions, thereby to allow the clip 24 to be pushed fully home so as tightly to compress the wire W between the plates 18 and 20. The plate 20 is bowed towards the plate 18 in the vicinity of the bight 22 so as to be contiguous with the plate 18 at the crest 40 of the bow. For piercing the usual varnish insulation V, which is provided on the magnet wire W, the plate 20 has serrations 42, of keystone shape, formed in its surface 44 which faces the plate 18, the serrations 42 extending from a free end edge 46 of the plate 20 towards the bight 22. The cavity 12 has a reduced cross section first portion 48 (best seen in Figure 4) which is remote from the open end 14 and receives the bight 22, and an enlarged portion 50 for receiving the clip 24, a shoulder 52 defined by the housing 4, between the cavity portions 48 and 50 serving to limit the movement of the clip 24 towards the bight 22. For securing the integrity of the connection between the terminal 16 and the wire W, the clip 24 has a resilient projection 54 at the lower end of each front wall 36 for engagement with the internal wall 56 of the cavity portion 50, as shown in Figure 5, thereby to restrain withdrawal of the clip 24 therefrom. The terminal 17 is provided with projecting barbs 58 on the longitudinal edges of the plates 18 and 20, in the vicinity of the bight 22 for engaging the wall 60 of the portion 48 of the cavity 12, to restrain withdrawal of the terminal 16 therefrom.

Claims: CLAIMS : 1. An electrical connector comprising an electrically insulating housing (4) having walls (6 and 8) defining a terminal receiving cavity (12) , the housing (4) having an open end (14) and an opposite end (10) , opposed walls (8) of the housing (4) each being formed with a wire receiving slot (16) extending from said open end (14) towards said opposite end (10) , and an electrical terminal (17) comprising a pair of juxtaposed wire gripping plates (18 and 20) connected in face to face spaced relationship by a bight (22) of the terminal material, the terminal (17) being insertable into the cavity (12) through said open end (14) with the bight (22) leading, to make electrical connection with a wire (W) extending through said wire receiving slots (16) ; characterized by a clip (24) which is slidable along the plates (18 and 20) towards the bight (22) to drive the plates (18 and 20) relatively towards each other to compress the wire (W) between them, following the insertion of the terminal (17) into the cavity (12) and the insertion of the wire (W) into the wire receiving slots (16) and between the plates (18 and 20) . 2. A connector according to claim 1, characterized in that an extension (26) of one plate (18) projects beyond the other plate (20) in a direction away from the bight (22) to provide a guide for the clip (24) and has embossed longitudinal edge portions (28) engageable with guide portions (30, 34) of the clip (24). 3. A connector according to claim 2, characterized in that the clip has a pair of end walls (32) with opposed beads (30) projecting inwardly of the clip (24) , each embossed edge portion (28) of the extension (26) being engageable with a rear wall (34) of the clip (24) and with one of the beads (30) . 4. A connector according to claim 1, characterized in that the clip (24) is formed with recesses for receiving the wire (W) as the clip is slid towards the bight (22) . 5. A connector according to claim 1, characterized in that one of the plates (20) is bowed towards the other plate (18) in the vicinity of the bight (22) so as to be contiguous with the one plate (18) at the crest of the bight (40). 6. A connector according to claim 1, characterized in that the cavity (12) has a reduced cross-section first portion (48) remote from said open end (14) , for receiving the bight (22) and an enlarged second portion (50) for receiving the clip (24) , a shoulder (52) defined between the first and second portions (48 and 50) of the cavity (12) serving to limit the movement of the clip (24) towards the bight (22). 7. A connector according to claim 6, characterized in that the clip (24) has a projection (54) for engaging a wall (56) of the second portion (50) of the cavity (12) , to secure the clip (24) therein, the terminal (17) having a projection (58) engageable with a wall (60) of the first portion (48) of the cavity (12) to secure the terminal (17) therein. 8. A connector according to claim 1, characterized in that one of the plates (20) is provided with insulation piercing serrations (42) for piercing varnish insulation (V) on the wire (W) as the wire (W) is compressed between the plates (18 and 20) . 9. An electrical terminal comprising a pair of juxtaposed wire gripping plates (18 and 20) connected in face to face spaced relationship by a bight (22) of the terminal material, the plates having free end edges (46 and 47) facing away from the bight (22) , an extension (26) of the one plate (18) projecting in a direction away from the bight (22) and beyond the other plate (20); characterized in that the other plate (20) is bowed towards the one plate (18) in the vicinity of the bight (22) so as to be contiguous with the one plate (18) at the crest (40) of the bow, the other plate (20) having serrations (42) formed in its surface (44) facing the one plate (18) and extending from the free end edge (46) of the other plate (20) towards the bight (22) .

Inventors: GRELLA GEORG, PLOESSER HARTMUTH GEORG FRIEDR, GRELLA, GEORG, PLOESSER, HARTMUTH, GEORG, FRIEDRICH
Applicants: AMP INC, AMP INCORPORATED
Application year: 1987
Main classification: H01R4
IPC codes: H01R4