Patent Application
20070082539
The present invention relates to a connector that produces an electrical connection with an insulated lead by displacing insulation surrounding a conductor and securing the lead against displacement relative to the connector. More particularly the invention pertains to such a connector for use in the electrical system of a motor vehicle.
Insulation displacement connection (IDC) is a technique employing a connector that engages the insulation surrounding an electrical conductor in order to secure the conductor to the connector. Conductor strain relief provides vertical conductor position assurance in the IDC holding the conductor in place to prevent movement of the conductor relative to the IDC interface and potential interface damage. It also improves conductor pull force performance by cutting into the insulation when the conductor is pulled vertically or longitudinally.
Conventional connectors in the prior art usually include strain relief and position definition features integrated into a mating part. These features often are in the form of bumps on a plastic connector cover, housing or another part of the connector. The bumps are used to form and IDC interface by pushing conductor into the IDC. But such connectors rely on the dimensional tolerance between the mating parts and positive mechanical locks to secure the parts mutually. Reliance on dimensional tolerances and mechanical locking permits great variability in the position of the conductor relative to the IDC interface and affects quality of the IDC interface.
It is preferable that an IDC rely instead on mechanical engagement with the conductor insulation to provide repeatable positioning of the conductor relative to the connector and to prevent displacement of the conductor relative to the connector, especially displacement resulting from conductor pulling forces, which is an important requirement of IDC performance.
An IDC according to the present invention secures the position of the conductor relative to the connector by positively engaging the insulation surrounding the conductor bundle. This feature prevents potential damage to the conductor that would occur if its position were not fixed. It also improves conductor pull force performance by cutting into the insulation when conductor is pulled vertically or longitudinally away from the connector.
A connector according to this invention provides at least two axially spaced slots having a transition length, whose width varies along its length, and a narrow throat, whose width is substantially smaller than the diameter of the conductor's insulation. Therefore, the slot engages the conductor with an interference fit as the conductor is pushed into the IDC interface. Further along the length of the slot, its width increases into a larger diameter recess having a hook-like shape that restrains the conductor in the IDC box when the conductor is inserted in and secured to the connector.
When a conductor is being inserted into the connector, the conductor's insulation is compressed against the sides of the slot due to its being loaded laterally against the slot. After passing the narrow throat of each slot, the conductor's insulation expands radially outward to produce preload interference contact with the retention or locking recess of the slot, thereby pushing conductor into the IDC interface. Edges of the slots can be sharp enough to partially penetrate into the insulation, thereby providing a lock that resists lateral movement of the conductor in the IDC.
An IDC according to this invention ensures better repealatchility of conductor-to-IDC position. Additional strain on the insulation prevents conductor movement in the IDC interface and provides additional conductor pull resistance, a critical performance advantage for an IDC.
When conductors are pulled vertically or longitudinally in a direction that would remove the conductors from the IDC, this removal is prevented by the IDC cutting into the insulation, retaining the conductor in the IDC, thereby making the IDC interface more robust and resistant to mechanical loads.
A connector, according to this invention, for engaging a conductor enclosed by insulation includes a housing including a base, the housing having a first slot directed toward the base, the slot formed with a throat whose width is less than a width of an outer surface of the insulation, and a retention recess communicating with the throat and having a width that is greater than the width of the throat, for engaging the conductor after the conductor passes along the slot through the throat into the retention recess.
The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:
Referring to the figures, an electrical connector 10 for securing a conductor 12 of insulated wire to the connector includes a rectangular box having a base, an open top, and four vertical walls 14, 16, 18, 20—two axial walls 14, 18 spaced mutually along the length of the conductor, and two lateral walls 16, 20 spaced mutually on opposite lateral sides of the conductor. The conductor 12 may include a single wire or a bundle of wires 24. In neither case, the conductor 12 is enclosed by a sheath of insulation material 22, which is usually in the form of a circular cylinder, preferably of plastic or another resilient material. The connector is formed of electrically conductive metal, preferably a copper alloy such as 5100 or beryllium copper.
Each of the axial walls 14, 18 is formed with a slot 26 directed generally downward from the upper surface 28 toward the base 30, which closes the box at its lower extremity. Each slot 26 is formed through the thickness of an axial wall and includes an upper tapered transition portion 32, whose width decreases as distance along the slot 26 from the upper surface 28 toward the base 30 increases. At the lower end of the transition 32, each slot 26 includes a throat 34, whose width is less than the outer diameter of the insulation 22 and less than the diameter of the bundle of wires 24 before installing the conductor 12 in the connector 10. Below the throat 34, the lateral surfaces 36, 38 of each slot 26 extend toward the base 30 and terminate in a semi-circular radius 42. As the conductor 12 is inserted in the connector 10, the insulation 24 is cut by the throat 34, and the sides 36, 38 of the slot compress the wires 24 laterally, thereby producing an elastic, electrically-conductive, interference contact between the wires and the connector slot.
Installation of the conductor 12 in connector 10 begins by placing the conductor on the transition portions 32, forcing the conductor downward against the latches 44, 46, deflecting and passing the conductor between the latches, passing the conductor through the throats 34, and moving the conductor downward along the slots 26 to the position illustrated in
After the conductor 12 reaches its proper position in the slots 26, represented in
A conductor according to this invention ensures excellent repeatability of the conductor-to-connector position. Additional strain on the insulation prevents conductor movement in the connector and provides additional conductor pull resistance, a critical performance advantage for a connector.
When the conductor is are pulled vertically or longitudinally in a direction that would remove the conductor from the connector, this removal is prevented by the connector cutting into the insulation, retaining the conductor in position, thereby making the connector more robust and resistant to mechanical loads.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.
