This invention relates to the classification of electrical connectors, and to one or more sub-classifications under spring actuated or resilient securing part. Specifically, this invention is a push-in electrical connector secured by an interior spring mechanism.
Over the past several decades, the amount of electronics in automobiles, and other on-road and off-road vehicles such as pick-up trucks, commercial trucks, semi-trucks, motorcycles, all-terrain vehicles, and sports utility vehicles (collectively “motor vehicles”). Electronics are used to improve performance, control emissions, and provide creature comforts to the occupants and users of the motor vehicles. Motor vehicles are a challenging electrical environments due to vibration, heat, and longevity. Heat, vibration, and aging can all lead to connector failure. In fact, loose connectors, both in the assembly plant and in the field, are one of the largest failure modes for motor vehicles. Considering that just the aggregate annual accrual for warranty by all of the automotive manufacturers and their direct suppliers is estimated at between $50 billion and $150 billion, worldwide, a large failure mode in automotive is associated with a large dollar amount.
Considerable time, money, and energy has been expended to find connector solutions that meet all of the needs of the motor vehicles market. The current common practice is to use an eyelet and threaded fastener on all high-power connections. The current common practice is expensive, time-consuming, and still prone to failure.
A more appropriate, robust connector solution must be impervious to vibration and heat. In order to create a robust solution, many companies have designed variations of spring-loaded connectors, which have a feature that retains the connector in place. Such spring-actuated connectors typically have some indication to show that they are fully inserted. Sometimes, the spring-actuated feature on the connector is made from plastic. Other times, the spring-actuated feature on the connector is fabricated from spring steel. Unfortunately, although the current state of the art is an improvement over connectors using an eyelet and threaded connector, there are still far too many failures.
Part of the reason that spring-actuated connectors still fail in motor vehicle applications is because the spring element is on the periphery of the connector. By placing the spring tab on the exterior surface of the connector, connector manufacturers tried to make engagement obvious to the person assembling the part. Unfortunately, for both plastic and metal, the increased temperatures of an automotive environment make a peripheral spring prone to failure. The engine compartment of the motor vehicle can often reach temperatures approaching 100° C., with individual components of a motor vehicle engine reaching or exceeding 180° C. At 100° C., most plastics start to plasticize, reducing the retention force of the peripheral spring-actuated feature. At 100° C., the thermal expansion of the spring steel will reduce the retention force of a peripheral spring-actuated connector by a small amount. More important, with respect to spring-actuated features fabricated from spring steel is the effect of residual material memory inherent in the spring steel as the spring steel is thermally cycled. After many temperature cycles, the spring steel will begin to return to its original shape, reducing its retention force and making is susceptible to vibration. The motor vehicle market needs a connector that is low-cost, vibration-resistant, temperature-resistant, and robust.
There is clearly a market demand for a mechanically simple, lightweight, inexpensive, vibration-resistant, temperature-resistant, and robust electrical connector. The problem is that all of these design criteria can be conflicting in current prior art. Some of the prior art has attempted to solve the problem using a peripheral spring-actuated retention feature. For example, U.S. Utility Pat. No. 8,998,655, by named inventors Glick, et. al., entitled, “Electrical terminal” (“Glick '655”) teaches an electrical terminal in which the contact element is a substantially polyhedron structure, with contact beams. A spring structure, external to the contact beams, exerts force on the contact beams. This arrangement is designed to force positive connection of the contact beams with a substantially round or square terminal pin. U.S. Utility Pat. No. 8,992,270, by named inventors Glick, et. al., entitled, “Electrical terminal” (“Glick '270”) teaches a variation on the Glick '655 patent. 0007 U.S. Utility Pat. No. 8,475,220, by named inventors Glick, et. al., entitled, “Electrical terminal” (“Glick '220”) teaches an electrical connector formed to have at least one pairs of opposing contact legs extending from a body portion, in which each leg extends to a contact point at which it touches the inner surface of the opposing leg contact. A spring clip can be positioned over one or more of the opposing legs to increase a compressive force. The spring clip may include an alignment feature to limit the clip from rotating and/or pitching. Glick '220 is designed to retain a largely flat or planar terminal element. U.S. Utility Pat. No. 8,366,497, by named inventors Glick, et. al., entitled, “Electrical terminal” (“Glick '497”) teaches a variation of Glick '220. All of the Glick patents have the same issue: repeated thermal cycling relaxes the spring steel, reducing the overall retention force. The reduction in the spring-actuated retention force makes the connector more susceptible to wiggling loose due to vibration. Intermittent connections are also a common failure mode. A solution is needed that improves upon the concept of the spring-actuated terminal connector.
This summary is intended to disclose the present invention, a high-power, spring-actuated electrical connector device. The embodiments and descriptions are used to illustrate the invention and its utility, and are not intended to limit the invention or its use.
The present invention has a male terminal and a female connector. The female connector fits inside the male terminal, when making an electrical connection. The present invention relates to using a spring-actuator inside the female connector to force contact beams into electrical contact with the male terminal. The present invention's contribution to the art is that the male terminal element is a metallic tubular member inside which fits the female connector. The female connector has a contact element, with a plurality of contact beams. A spring actuator is nested inside the contact element. The spring actuator applies force on the contact beams, creating a positive connection and retention force.
Unlike the prior art, material memory and thermal expansion will increase, not decrease, the retention force and electrical contact of the present invention.
The male terminal has a metallic tubular member which has an inner surface, an outer surface, and a defined cross-sectional profile. The metallic tubular member is fabricated from a sheet of highly conductive copper. The highly conductive copper can be C151 or C110. One side of the sheet of highly conductive copper can be pre-plated with silver, tin, or top tin, such that the inner surface of the metallic tubular member is plated.
The female connector has a contact element and a spring actuator. The contact element has a plurality of contact beams. In the preferred embodiments, at least four contact beams are needed, so that force is exerted on the inner surface of the metallic tubular member is symmetrical. Four beams can be placed at 90° increments, meaning that each beam has one beam directly opposing it within the metallic tubular member; and two beams orthogonal to each member within the metallic tubular member. Each contact beam has a thickness, a bent-termination end, and a planar surface with a length and a width. The contact beam is connected to a contact base at the distal end from the bent-termination. In the illustrated embodiments, the contact element has an even number of beams, which are symmetrical and are evenly spaced. The contact element base cross-section can be round, square, triangular, or polygonal. The illustrated embodiments show contact elements with square and hexagonal cross-sectional profiles. The illustrated embodiments show contact elements with four and six beams.
A spring actuator is nested inside the contact element. The spring actuator has spring arms and a base. The spring arms are connected to the base at one end. The spring arms have a bent-termination end, a thickness, and a planar surface with a length and width. In the illustrated embodiments, the spring actuator has the same number of spring arms as the contact element has contact beams. In the illustrated embodiment, the spring arms can be mapped, one-to-one, with the contact beams. The spring arms are dimensioned so that the bent-termination end of the associated contact beam contacts the planar surface of the spring arm. The spring arms of the illustrated embodiments are even in number, symmetrical, and evenly spaced.
The contact element fits inside the metallic tubular member such that the contact beams contact the inner surface of the metallic tubular member. The spring arms force the contact beams into electrical connection with the metallic tubular member. The bent-termination end of the contact arm meets the planar surface of the spring arm, forcing the contact beam to form a large obtuse angle with respect to the contact element base.
In the illustrated embodiments of the present invention, although not required, the metallic tubular member has a symmetrical cross-section. The most important design criteria is that the compliance (inverse of stiffness) exerted on each beam, forcing each beam into contact with the inner surface of the metallic tubular member, be balance by the compliance of all of the other contact beam and spring-arm pairs such that the female connector is kept centered within the metallic tubular member by the force exerted by the beam/spring arm pairs.
The male terminal and female connector are both surrounded by a non-conductive shroud. For the male terminal, only the inner surface of the metallic tubular member is exposed. For the female connector, only the contact beams are exposed.
The male terminal can be connected to a busbar or other circuit. For example, in an alternator application, the metallic tubular member can be integral with the alternator busbar. The non-conductive plastic shroud would wrap the exterior of the metallic tubular member leaving the inner surface and the busbar exposed. Typically, in such an application, the busbar of the alternator is going to be interior to the alternator housing
The present invention is illustrated with 44 drawings on 12 sheets.
The following descriptions are not meant to limit the invention, but rather to add to the summary of invention, and illustrate the present invention, by offering and illustrating various embodiments of the present invention, a high-power, spring-actuated electrical connector. While embodiments of the invention are illustrated and described, the embodiments herein do not represent all possible forms of the invention. Rather, the descriptions, illustrations, and embodiments are intended to teach and inform without limiting the scope of the invention.
The contact element 10 is an integral piece. The contact element 10 is made out of conductive metal, such as copper alloys C151 or C110. It is formed, bend, and folded into the correct shape. The contact element 10 has two planar spade elements 16, 17. The planar spade elements 16, 17 have a thickness 16, 17. The planar spade elements 16, 17 have a planar surface 15, 105. The planar spade elements 16 transitions 106 from the hexagonal base 18, 19. The transition 106 has a thickness 107.
The spring actuator 30 fits inside the contact element 10. The spring actuator 30 spring arms 31 contact the inside planar surface 122 of the contact element 10 contact beams 11. The inside planar surface 122 of the contact beams 11 is obverse to the outside planar surface 12 of the contact beams 11. The bent-termination portion 13 of the contact element 10 allows the female connector 20 to be compressed as it is inserted into a connector block. The spring actuator 30 spring arms 31 will provide a consistent retention force against the inside surface 122 of the contact element 10 contact beams 11. In practice, it is advisable to use a minimum of four (4) contact beams 11 in any embodiment.
The contact element 60 is an integral piece. The contact element 60 is made out of conductive metal, such as copper alloys C151 or C110. It is formed, bend, and folded into the correct shape. The contact element 10 has two planar spade elements 66, 67. The planar spade elements 66, 67 have a thickness 616, 67. The planar spade elements 66, 67 have a planar surface 65, 155. The planar spade elements 66 transitions 156 from the hexagonal base 68, 69, 168. The transition 156 has a thickness 171.
The spring actuator 80 fits inside the contact element 60. The spring actuator 80 spring arms 81 contact the inside planar surface 222 of the contact element 60 contact beams 61. The bent-termination portion 63 of the contact element 60 allows the female connector 70 to be compressed as it is inserted into a connector block. The spring actuator 80 spring arms 81 will provide a consistent retention force against the inside surface 222 of the contact element 60 contact beams 61.
The female connector 20, 70 fits inside the male terminal portion 1. At elevated temperatures, the contact element 10, 60, and the spring actuator 30, 80, will tend to expand outwards due to metal memory and thermal expansion. This will increase the outward directed spring force exerted by the spring arms 31, 81 on the contact beams 11, 61. In turn, this will increase the contact force between the contact beams 11, 61 and the inner cylindrical surface 9 of the male terminal portion 1. As a result, the increased temperatures present in a motor vehicle engine compartment will increase, rather than decrease, the contact force of the connector.
The contact element 310 is an integral piece. The contact element 310 is fabricated from a conductive metal, such as copper alloys C151 or C110. It is formed, bend, pressed, and/or folded into the correct shape. The contact element 310 has two planar spade elements 316, 317. The planar spade elements 316, 317 have a thickness 316, 317. The planar spade elements 316, 317 have a planar surface 315. The planar spade elements 316 transitions 357 from the hexagonal base 350. The transition 350 has a thickness 357. A spring actuator 330 is interior to the contact element 310.
The contact element 410 is an integral piece. The contact element 410 is fabricated from a conductive metal, such as copper alloys C151 or C110. It is formed, bend, pressed, and/or folded into the correct shape. The contact element 410 has two planar spade elements 416, 417. The planar spade elements 416, 417 have a thickness 416, 417. The planar spade elements 416, 417 have a planar surface 455. A spring actuator 430, with spring arms 431 is interior to the contact element 410. The female connector 420 has, generally, a length 470 and a width 471. A ratio of length 470 to width 471 is the aspect ratio of the female connector 420.
The alternator terminal assembly 700 mates with the male terminal 703, as shown in
Number | Date | Country | |
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Parent | 15283242 | Sep 2016 | US |
Child | 15905806 | US |