Patent Application
20140199862
The Present Disclosure relates generally to board mounted connectors, and more particularly, to such connectors having improved compliant mounting pins that offer beneficial insertion and retention capabilities.
Many electronic devices utilize internal circuit boards for circuitry and as a platform upon which to mount integrated circuits, switches, components and the like, including connectors. These connectors are often surrounded with a conductive shielding member that takes the form of a cage to provide grounding and shielding against electromagnetic interference radiation, known as “EMI.” These shields may be mounted to the surface of the circuit board, such as by soldering, or they may be provided with a plurality of members in the form of mounting pins that extend downwardly therefrom and which are received in openings formed in the circuit board. These openings are formed as plated through holes, or “vias,” directly in the circuit board and have a conductive metal plating applied to their inner surfaces, or sidewalls. The pins are formed as compliant members and are known in the art as press-fit pins or compliant pins. These pins are larger in overall size than the holes and this dimensional difference permits the pins to firmly engage the sidewalls of the holes and thereby form an electrical connection between the cage and the circuit boards. In addition to their use with shielding cages, compliant pins may also be used with electrical connectors for the same mounting purpose, and may be used directly as terminal tail portions in both connectors and other electronic components, such as switches, integrated circuits and the like.
There are problems in the use of press-fit compliant pins and these problems include inadequate performance during insertion into and retention by a circuit board. The cross-section of some pins may be lacking in structural integrity such that those pins may bend or buckle when the pins are inserted into their associated through holes. If the pins buckle during insertion they will not be fully inserted into the holes and may deform more than expected. This lack of full insertion and/or excessive deformation negatively affects the electrical contact between the pins and the surrounding vias and requires the cage to be removed and replaced, but in doing so, the buckled configuration of the pins may give rise to the possibility of damage to the expensive circuit board.
Similarly, if the pins buckle during insertion, they may provide adequate electrical contact with the circuit board but their retention capability may be diminished to the point where the electrical contact becomes sporadic and intermittent after the device in which the cage is used proceeds through assembly, packing, shipping and installation at an end user. This intermittent contact may not be discovered until the product is placed into service at the end user or shortly thereafter, thereby necessitating return of the device to the manufacturer.
The Present Disclosure is therefore directed to a compliant pin having an improved structure that offers greater resistance to buckling.
Accordingly, there is provided an improved compliant pin that has a cross-section configured to better resist buckling during insertion into a circuit board opening.
In accordance with a first embodiment as described in the following Present Disclosure, a compliant pin particularly suitable for use in association with a conductive shielding cage is provided with an elongated body which has an internal opening, or “eye,” positioned within the pin body at a level beneath the circuit board-cage interface so that more material is present in this area which enhances the resistance to buckling of the compliant pin upon insertion and removal.
In accordance with a second embodiment as described in the Present Disclosure, a non-symmetrical opening is formed in the pin body. The opening is symmetrical around a vertical axis, but not around an associated horizontal axis. As such, the opening has a given width at its upper extent that increases along the depth of the pin body so that the width of the bottom of the pin opening is wider, or larger, than that at the top of the pin opening and this larger opening is located below the circuit board-cage interface. More material is thus present in the upper portions of the pin body, and as such, the pin body has a greater moment of inertia and therefore a greater resistance to bending and buckling
These and other objects, features and advantages of the Present Disclosure will be clearly understood through a consideration of the following detailed description.
The organization and manner of the structure and operation of the Present Disclosure, together with further objects and advantages thereof, may best be understood by reference to the following Detailed Description, taken in connection with the accompanying Figures, wherein like reference numerals identify like elements, and in which:
While the Present Disclosure may be susceptible to embodiment in different forms, there is shown in the Figures, and will be described herein in detail, specific embodiments, with the understanding that the Present Disclosure is to be considered an exemplification of the principles of the Present Disclosure, and is not intended to limit the Present Disclosure to that as illustrated.
As such, references to a feature or aspect are intended to describe a feature or aspect of an example of the Present Disclosure, not to imply that every embodiment thereof must have the described feature or aspect. Furthermore, it should be noted that the description illustrates a number of features. While certain features have been combined together to illustrate potential system designs, those features may also be used in other combinations not expressly disclosed. Thus, the depicted combinations are not intended to be limiting, unless otherwise noted.
In the embodiments illustrated in the Figures, representations of directions such as up, down, left, right, front and rear, used for explaining the structure and movement of the various elements of the Present Disclosure, are not absolute, but relative. These representations are appropriate when the elements are in the position shown in the Figures. If the description of the position of the elements changes, however, these representations are to be changed accordingly.
The compliant pins 26 are arranged in a pattern around the outer edges 29 of the bottom of the shielding cage 20. Some of these pins 26 may be formed with the sidewalls 25 of the cage 20 while others may be formed as part of the endwall 30 of the shielding cage 20. The pattern of the compliant pins preferably is staggered as between the two rows of pins 26 depending down from the two opposing sidewalls 25 of the cage 20, as shown in
These distinct pin portions include a pin tip portion 32, which extends from the bottom end 33 of the compliant pin 26 to approximately the bottom edge 34 of a pin opening 35. A pin body portion 36 is disposed adjacent the pin tip portion 32, and it extends lengthwise along the pin 26 between the pin tip portion 32 and the pin base portion 37. As such, the pin body portion 36 extends along the outer edges 38 of the pin opening 35 and may be considered as at least partially enclosing the pin opening 35. The pin body portion 36 has a width greater than the widths of either the pin tip portion 32 or the pin base portion 37. This width varies along the length of the compliant pin 26.
Lastly, the pins 26 may also include a pin base portion 37 that extends down from the cage walls and joins the pin body portion 36 to the shielding cage walls (or in the case of a connector terminal, the terminal body portion). The pin base portion 37 extends to approximately the top edge 39 of the pin opening 35. The compliant pin base portion 37 may be partially separated from the cage walls 25, 30, illustrated by a pair of first slots 42, shown as reentrant notches 43 that extend upwardly with respect to the compliant pins 26. In the embodiment shown, these first slots 42 separate the pin base portions 37 from portions 45 of the sidewalls 25, shown as stubs or the like, and which may serve as “standoffs” 46 that make direct contact with the top surface 22 of the circuit board 21. These standoffs 46 serve as a point of direct contact “CI” with the circuit board 21 proximate to the compliant pin 26, and accordingly, each has a hard, substantially flat, or linear edge 47. This is in contrast to the approximate rounded edge 48 running the length of the sidewalls 25, obtained from the ordinary forming of the cage 20. A pair of second slots 49, also extending upwardly into the cage walls are shown as flanking the standoffs 46 and permit them to be formed so that they occupy a preferred perpendicular orientation to the circuit board top surface 22.
In an important aspect of the Present Disclosure, the pin opening 35 is disposed at a certain location within the pin body portion 36; specifically, at a level beneath the connector-cage interface (best shown by “CI” in
The extra material in the pin base portion 37 increases the moment of inertia of the section taken through the pin base portion 37 and the section is a complete rectangle, having a width W and a thickness T as shown in
Another embodiment of a compliant pin 26′ constructed in accordance with the Present Disclosure is illustrated in
The narrow top portion 51 of this pin opening 50 coincides with a top apex 60 of the imaginary triangle, while the widest bottom portions 53 coincide with the bottom apexes 61 of the imaginary triangle.
As such, the pin opening 50 of this embodiment is symmetrical around a vertical axis Y-Y, but asymmetrical around a horizontal axis X-X. Shapes other than that shown may be used provided that the bottom portion of the opening is wider than the top portion.
While a preferred embodiment of the Present Disclosure is shown and described, it is envisioned that those skilled in the art may devise various modifications without departing from the spirit and scope of the foregoing Description and the appended Claims.
