The invention generally relates to electrical connection system, and more particularly relates to an electrical connection system having an electrical terminal with contact ridges that are configured to provide a reduced terminal engagement force.
In electrical connection systems using stamped terminals, the female stamped terminal may include a ribbed contact surface to provide a concentrated contact point for the male terminal. In some applications, this contact surface in the female terminal is embossed and abruptly rises into the path of the male terminal as the connection system is being mated as illustrated in
The reoccurring customer complaint with connection systems is that the engagement force of the two mating connectors is too high. While there are a number of methods that can be used to reduce the engage force, some changes are more efficient than others. Some connectors have used different materials for their stamped terminals that has a lower coefficient of friction while others have used lubricants such as grease or oil.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.
According to a first embodiment, an electrical connection system is presented, The electrical connection system includes a male terminal and a female terminal configured to receive the male terminal. The female terminal has a resilient contact defining a ridge or a plurality of ridges extending vertically from the contact and longitudinally along the contact. The resilient contact may be characterized as a cantilever beam. The ridge is configured to provide a contact point between the female terminal and the male terminal. The resilient contact may have an arcuate shape that defines an apex and the ridge extends over the apex. A leading edge of the ridge forms an angle with the resilient contact that is greater than 0 degrees and less than or equal to 30 degrees. The angle may preferably be about 10 degrees. The leading edge may be substantially linear. The ridge may be formed by embossing the contact.
According to a second embodiment, a female electrical socket terminal configured to receive a corresponding male plug terminal is presented. The female electrical socket terminal includes a resilient contact configured to contact the male plug terminal and a longitudinal protrusion projecting from a top surface of the contact. The resilient contact may be characterized as a cantilever beam. The resilient contact may have an arcuate shape that defines an apex and the longitudinal protrusion extends over the apex. The longitudinal protrusion is configured to provide a point contact between the contact and the male plug terminal. The longitudinal protrusion may be formed in the contact by an embossing process. The female electrical socket terminal further includes a ramp on a forward edge of the longitudinal protrusion. The ramp has a second top surface that forms an angle relative to the first top surface that is greater than 0 degrees and less than or equal to 30 degrees. The angle may preferably be about 10 degrees. The ramp may be substantially linear.
Further features and advantages of the invention will appear more clearly on a reading of the following detailed description of the preferred embodiment of the invention, which is given by way of non-limiting example only and with reference to the accompanying drawings.
The present invention will now be described, by way of example with reference to the accompanying drawings, in which:
Corresponding features of the various examples presented herein have reference numbers that differ by 100, e.g. 10, 110, 210.
The inventor has observed that the engagement force when one terminal is inserted into another follows a pattern: as the male terminal is inserted into the female terminal, the force required to overcome the frictional forces and reaction forces from the female terminal increases to a peak value and then is reduced and stabilizes to a relatively constant engagement force until the male terminal is fully inserted within the female terminal. In order to reduce customer complaints of high engagement force, the peak engagement force should be reduced as much as possible.
The connection system presented herein reduces the peak engagement force by increasing the lead-in angle on the stamped ribs on the female terminal. In most cases, the contact ribs are embossed into the metal and when the male interface is inserted, it stubs against this raised material until the force applied is great enough to slide up and over the embossed material. The proposed invention is a graduated emboss wherein a lead-in angle is applied to the embossed material such that upon insertion, the mating male interface gradually encounters the contact ribs and requires less force to overcome the raised material.
While the illustrated embodiments include a pair of contacts ridges, alternative embodiments may be envisioned having a single contact ridge or more than two contact ridges. While the ramp in the illustrated example is formed during the embossing process, embodiments using other methods to form the ramp, such as grinding or material deposition. The ramp on the leading edge may also be applied to other terminal designs, including male bladed terminals in order to reduce peak engagement force.
Accordingly, an electrical connection system 10 having a female terminal 222 is provided. The ramps 234 formed on the leading edges of the contact ridges 224 of the female terminal 222 provide the benefit of a point contact between the male terminal and the female terminal 222 while reducing the peak engagement force 236, 238, 240 experienced by an operator when mating the female and male terminals.
While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow. Moreover, the use of the terms first, second, etc. does not denote any order of importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.