GB1586231A

GB1586231A - Electrical terminal connector

Info

Publication number: GB1586231A
Application number: GB24807/77A
Authority: GB
Original assignee: Thorn EMI Ltd
Current assignee: Thorn EMI Ltd
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-03-18

Description

(54) ELECTRICAL TERMINAL CONNECTOR (71) We, THORN EMI LIMITED, formerly known as Thorn Electrical Industries Limited, a British Company, of Thorn House, Upper St. Martin's Lane, London WC2H 9ED, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention is concerned with an electrical terminal and a method for making an electrical connection between the terminal and an insulated wire conductor.

Electrical terminals for making contact with insulated wire conductors are well known. Many rely in their operation on the use of a slot having sharp edges to remove insulating material from the insulated wire when it is forced into the slot and thereby establish an electrical connection. This type of connector can only be used with insulated wire which has a conductor diameter slightly larger than or equal to the width of the slot.

For this reason the slots in the connectors have to be manufactured with closely controlled tolerances to ensure that they will make d reliable connection with the wire and the connectors can only be used with one size of wire.

According to the present invention there is provided a terminal for making an electrical connection with an insulated wire conductor comprising a bar of electrically conductive material having a plurality of slots of sub stantially rectangular cross-section distri buted along part of its length and having widths which progressively increase in one direction along the length of the bar, each of the slots extending transverse to the length of the bar and having edges capable of remov ing insulator and conductor material from an insulated wire having a conductor dia meter larger than the width of the slot when the wire is pressed into the slot.

The bar is preferably a fiat bar with the slots formed in opposite edges of the bar to extend between the two principal surfaces of the bar. The slots along one edge may be staggered relative to the slots along the other edge such that the wire when wound around the bar to engage in the slots will follow a flattened helical path.

The insulated wire is preferably wound around the terminal several times and pressed into the slots. In this way the wire is securely held in position and the slots in which the wire conductor contacts the surface of the slot wall provide a reliable electrical connection.

In the slots which have widths smaller than the diameter of the wire conductor, conductor material is removed from both the bar and the wire during the pressing operation and the resulting clean conductor surfaces are brought into contact free from grease and surface oxidation films. The insulated wire is preferably wound around the terminal so that the portion which is pressed into the narrowest slot is closest to the end of the wire. This is to avoid the possibility of the wire breaking at a weak point created by the removal of conductor material.

The bar may have a substantial length extending beyond the narrowest slot to form a pin for insertion in a contact socket. At the other end the bar may have a portion of increased width beyond the widest slot which portion can be embedded in an insulating support. A terminal with these features is suitable, for example, for use as a bobbin tag which is embedded in a core on which is wound a coil of insulated wire (for example a choke coil) the ends of which are attached to respective bobbin tags. A single connector with a pair of contact sockets can then engage the two tags.

In accordance with the invention there is also provided a method of making an electrical connection between an insulated wire conductor and a terminal in accordance with the invention wherein portions of the wire which are progressively nearer a free end of the wire are arranged to lie along the tops of successively narrower slots of the bar with the axis of each said portion of the wire perpendicular to the plane of the rectangular cross-section of the corresponding slot and the said portions of the wire are pressed into the slots thereby removing insulator material and at least in some cases conductor material from the insulated wire and forming an electrical connection between the wire conductor and the bar.

The features of the invention will now be described in greater detail with reference to the accompanying drawings, in which: Figures 1 and 2 represent a connector tag embodying the features of the present invention at two stages in the attachment of an insulated wire, and Figure 3 is a schematic drawing similar to Fig. 1 but illustrating a modification of the connector tag.

Figure 1 shows a flat brass connector tag 1 with a rectangular cross-section, only one of the principal surfaces of the fiat tag being visible in the drawing. Slots 2 are cut in two opposite edges of the tag and are staggered so that the insulated wire 3 can be conveniently wound around the tag in a helical fashion to rest on the tops of the slots 2 as shown. The slots extend between the two principal surfaces of the tag transverse to the length of the tag and have a rectangular cross-section and their widths progressively increase in the direction of the arrow d.

In a preferred connector tag the centres of the slots are separated by 0-36 mm and their widths vary from a minimum value of 0e25 mm to a maximum value of 0 36 mm and may be used with a range of enamelled wires having a nominal copper wire diameter from 0 355 rarn to 0 450 mm. The slots may be slightly tapered inwards to grip the wire more tightly the further it is pressed in or they may have parallel side walls as shown in Figure 1.

The plates 4 and 5 are used to press the insulated wire into the slots 2 and the sharp slot edges 2B remove varying amounts of conductor and/or insulator material from the. wire according to the slot widths. When the insulated wire is in position in the slots as shown in Figure 2, the wrap around configuration and the tight fit in the slots provide a secure physical grip on the wire.

An electrical connection is formed where the walls of the slots contact the bared wire conductor.

Figure 3 shows a modification of the connector tag described above and incorporates angled lead-ins formed by sloping surfaces 6 at the entrances to the slots 2. The lead-ins help to guide and position the insulated wire 3. correctly over the slots before they are pressed in. To press the insulated wire into the slots, special plates 7 and 8 are used and have projections 9 on their faces which match the, shape of the lead-ins. In all other respects the connector tag of Figure 3. is the same as that of Figure 1 and the electrical connection is formed by the removal of conductor and/or insulating material from the insulated wire by the edges of the slots and contacting of the slot walls with the bared wire conductor.

The tags 1 shown in the drawings each have a portion 1A which extends for a substantial length beyond the narrowest slot to form a pin for insertion in a contact socket and a portion IB beyond the widest slot which is of increased width and can be embedded in an insulating support. The free end of the wire 3 can be mechanically secured to the tag near the inner end of the portion 1A, for example by soldering, WHAT WE CLAIM IS: 1. A terminal for making an electrical connection with an insulated wire conductor comprising a bar of electrically-conductive material having a plurality of slots of substantially rectangular cross-section distributed along apart of its length and having widths which progressively increase in one direction along the length of the bar, each of the slots extending transverse to the length of the bar and having edges capable of removing insulator and conductor material from an insulated wire having a conductor dia meter larger than the width of the slot when the wire is pressed into the slot.

2. A terminal as claimed in claim 1 wherein the bar is a fiat bar with the slots formed in the opposite edges of the bar to extend between the two principal surfaces.

3. A terminal as claimed in claim 2 in which the slots along one edge are. staggered relative to the slots along the other edge such that the wire when wound around. the bar to engage in the slots will follow a flattened helical path.

4. A terminal as claimed in any of claims I to 3 in which the bar has a suS stantical length extending beyond the narrow- est slot to form a pin for insertion in a contact socket.

5. A terminal as claimed in, any of claims 1 to 4 in which the bar has a portion of increased width beyond the widest slot which portion can be embedded in, an insulating support.

6. A terminal as claimed in any of claim 1 to 5 in which each of the slots has angled lead-in surfaces to guide the wire into the slot.

7. A terminal for making an electrical connection with an insulated wire conductor substantially as described with reference to Figs. 1 and 2 or Fig. 3 of the accompanying drawings.

8. A method of making an electrical connection between an insulated wire conductor and a terminal as claimed in any of the preceding claims wherein portions of the wire which are progressively nearer a free end of the wire are arranged to lie along the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

the said portions of the wire are pressed into the slots thereby removing insulator material and at least in some cases conductor material from the insulated wire and forming an electrical connection between the wire conductor and the bar.

The features of the invention will now be described in greater detail with reference to the accompanying drawings, in which: Figures 1 and 2 represent a connector tag embodying the features of the present invention at two stages in the attachment of an insulated wire, and Figure 3 is a schematic drawing similar to Fig. 1 but illustrating a modification of the connector tag.

Figure 1 shows a flat brass connector tag 1 with a rectangular cross-section, only one of the principal surfaces of the fiat tag being visible in the drawing. Slots 2 are cut in two opposite edges of the tag and are staggered so that the insulated wire 3 can be conveniently wound around the tag in a helical fashion to rest on the tops of the slots 2 as shown. The slots extend between the two principal surfaces of the tag transverse to the length of the tag and have a rectangular cross-section and their widths progressively increase in the direction of the arrow d.

In a preferred connector tag the centres of the slots are separated by 0-36 mm and their widths vary from a minimum value of 0e25 mm to a maximum value of 0 36 mm and may be used with a range of enamelled wires having a nominal copper wire diameter from 0 355 rarn to 0 450 mm. The slots may be slightly tapered inwards to grip the wire more tightly the further it is pressed in or they may have parallel side walls as shown in Figure 1.

The plates 4 and 5 are used to press the insulated wire into the slots 2 and the sharp slot edges 2B remove varying amounts of conductor and/or insulator material from the. wire according to the slot widths. When the insulated wire is in position in the slots as shown in Figure 2, the wrap around configuration and the tight fit in the slots provide a secure physical grip on the wire.

An electrical connection is formed where the walls of the slots contact the bared wire conductor.

Figure 3 shows a modification of the connector tag described above and incorporates angled lead-ins formed by sloping surfaces 6 at the entrances to the slots 2. The lead-ins help to guide and position the insulated wire 3. correctly over the slots before they are pressed in. To press the insulated wire into the slots, special plates 7 and 8 are used and have projections 9 on their faces which match the, shape of the lead-ins. In all other respects the connector tag of Figure 3. is the same as that of Figure 1 and the electrical connection is formed by the removal of conductor and/or insulating material from the insulated wire by the edges of the slots and contacting of the slot walls with the bared wire conductor.

The tags 1 shown in the drawings each have a portion 1A which extends for a substantial length beyond the narrowest slot to form a pin for insertion in a contact socket and a portion IB beyond the widest slot which is of increased width and can be embedded in an insulating support. The free end of the wire 3 can be mechanically secured to the tag near the inner end of the portion 1A, for example by soldering, WHAT WE CLAIM IS: 1. A terminal for making an electrical connection with an insulated wire conductor comprising a bar of electrically-conductive material having a plurality of slots of substantially rectangular cross-section distributed along apart of its length and having widths which progressively increase in one direction along the length of the bar, each of the slots extending transverse to the length of the bar and having edges capable of removing insulator and conductor material from an insulated wire having a conductor dia meter larger than the width of the slot when the wire is pressed into the slot.
2. A terminal as claimed in claim 1 wherein the bar is a fiat bar with the slots formed in the opposite edges of the bar to extend between the two principal surfaces.
3. A terminal as claimed in claim 2 in which the slots along one edge are. staggered relative to the slots along the other edge such that the wire when wound around. the bar to engage in the slots will follow a flattened helical path.
4. A terminal as claimed in any of claims I to 3 in which the bar has a suS stantical length extending beyond the narrow- est slot to form a pin for insertion in a contact socket.
5. A terminal as claimed in, any of claims 1 to 4 in which the bar has a portion of increased width beyond the widest slot which portion can be embedded in, an insulating support.
6. A terminal as claimed in any of claim 1 to 5 in which each of the slots has angled lead-in surfaces to guide the wire into the slot.
7. A terminal for making an electrical connection with an insulated wire conductor substantially as described with reference to Figs. 1 and 2 or Fig. 3 of the accompanying drawings.
8. A method of making an electrical connection between an insulated wire conductor and a terminal as claimed in any of the preceding claims wherein portions of the wire which are progressively nearer a free end of the wire are arranged to lie along the

tops of successively narrower slots of the bar with the axis of each said portion of the wire perpendicular to the plane of the rectangular cross-section of the corresponding slot and the said portions of the wire are pressed into the slots thereby removing insulator material and at least in some cases conductor material from the insulated wire and forming an electrical connection between the wire conductor and the bar.
9. A method as claimed in claim 8 in which the wire is wound around the terminal to engage with the slots.
10. A method as claimed in claim 8 or 9 in which the free end of the wire is secured to the terminal.
11. A method of making an electrical connection between an insulated wire conductor and a terminal substantially as described with reference to the accompanying drawings.