Electrical connectors – Metallic connector or contact having movable or resilient... – Spring actuated or resilient securing part
Reexamination Certificate
2001-01-05
2001-09-25
Ta, Tho D. (Department: 2833)
Electrical connectors
Metallic connector or contact having movable or resilient...
Spring actuated or resilient securing part
C439S839000, C439S852000
Reexamination Certificate
active
06293833
ABSTRACT:
FIELD OF THE INVENTION
The present invention is in the field of electrical terminal contact springs, in particular those used in wire harness connectors of the automotive type.
BACKGROUND OF THE INVENTION
Wire harnesses are frequently used in the automotive industry to make electrical connections between various vehicle components, power sources, and systems. Female wire harness terminals in these types of connectors typically take the form of a cantilevered spring contact set at an angle to form a deflectable ramp inside an at least partially enclosed terminal chamber. As a male terminal is inserted in the female chamber, it wipes against and displaces the female ramp contact under spring tension such that, when fully inserted, the spring tension of the female contact establishes a secure electrical connection between the terminals.
It is desirable to form the female spring contact with a strong spring force so as to maintain a good electrical connection despite the vibration normally encountered by wire harness connections in vehicles.
Because the space inside the female terminal chamber is limited, and because the depth of insertion of the male terminal into the female terminal is limited, the space in which the female spring contact can be designed to produce an effective spring force against the inserted male contact is limited. In an effort to improve the spring force of a simple cantilevered spring contact, the prior art (see
FIGS. 1 and 2
) has typically relied on an independent, secondary spring element
1
,
1
′ located in the female terminal chamber
2
,
2
′ to engage a portion of the female spring contact
3
,
3
′ and increase the force with which it yields upon insertion of the male contact in the direction of the arrow.
These secondary spring elements, however, tend to be difficult to manufacture and install to tight tolerances, and tend to increase the length of the female terminal chamber, neither of which is desirable. Additionally, the insertion force for the male contact is significantly increased.
SUMMARY OF THE INVENTION
The present invention is a cantilevered female spring contact for a wire harness terminal chamber in which the female spring contact is formed from a single piece of metal to include both primary and secondary spring elements. The secondary spring element is placed so as to be activated only at or near full insertion of a male contact in the female terminal chamber. Further, the secondary spring contact is located below the primary female spring contact, and is shorter than the primary spring contact, such that the contact as a whole requires no more space in the terminal chamber than would a simple, single-element cantilevered contact.
In a first embodiment, the cantilevered spring ramp against which the male terminal is inserted has secondary spring arms formed from its outer edges. The outer arms are bent downwardly below the plane of the ramp, and further are spaced above the base of the contact in the female contact's at-rest position, such that partway through the insertion of the male terminal (preferably at or near full insertion) the ramp is deflected sufficiently to lower the secondary spring arms into engagement with the contact base, thereby increasing the final spring force acting against the male terminal in the chamber. At the same time, the initial terminal insertion force is not increased.
In a second embodiment of the invention, an inner or middle portion of the ramp is cut free at a rearward end of the terminal and bent downwardly to form the secondary spring element. In a further preferred form of this second embodiment, the secondary spring element is bent generally in a V-shape with a rearward, raised portion which engages the underside of the ramp to increase the spring force when the lowermost portion of the V engages the contact base. In this second embodiment, the insertion force does not increase until a point at or near full terminal insertion, resulting in normal insertion force with a higher final retention force.
In a third embodiment of the invention, the ramp element is slotted down an interior portion, the slot extending through the spring radius of the ramp to reduce the initial insertion force. Additionally, material removed from the ramp, radius, and contact base to extend the slot around the spring radius is itself bent upwardly and rearwardly as a separate, cantilevered, secondary spring element whose free end is located underneath a rearward portion of the ramp. When an inserted male terminal nears the end of its insertion, and engages the rearward portion of the ramp, the ramp is forced downwardly and comes into contact with the cantilevered free end of the secondary spring element to increase the final retention force.
In a fourth embodiment of the invention, the primary spring ramp is slotted down the middle, and the secondary spring element, whether connected to the ramp or to the base, is located below and aligned with the slot or aperture so as to be raised through the slot into engagement with the inserted male terminal as the primary ramp is depressed. In a preferred form, the secondary spring element is connected to a forward portion of the ramp, and is bent downwardly with a V-shape such that its rearward, uppermost end forms a secondary electrical contact to engage the underside of the male terminal through the slot.
Additional features and advantages of the invention will become apparent upon further reading of the specification, in light of the accompanying drawings.
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Ta Tho D.
Yazaki North America
Young & Basile
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