1. Field of the Invention
This invention relates to a resilient clip holding a heat sink in place against an electronic package within a socket, while simultaneously holding a movable portion of the socket in a locked position, with engagement forces retained between contacts within the socket and pins descending from the electronic package.
2. Background Information
Developments in integrated circuits have resulted in greater circuit density and complexity, increasing the number of pins necessary to connect power and signal lines between an electronic package and the circuit board to which it is attached, and increasing the heat generated by operation of an integrated circuit within the electronic package. These changes in integrated circuits have in turn resulted in increased needs for LIF (Low Insertion Force) and ZIF (Zero Insertion Force) sockets into which electronic packages are inserted, and in increased needs for heat sinks clamped to outer surfaces of electronic packages. The insertion force is the force required to plug the electronic package into a socket, typically arising from the deflection and friction forces acting between the individual pins descending from the electronic package and individual contact springs within the socket. Seating a high pin-count electronic package in a socket without the LIF or ZIF feature can require a force of over 250 pounds.
A ZIF feature is conventionally achieved, within a socket having an array of holes into which the pins descending from an electronic package are inserted, through the use of a sliding locking member operating on the module pins or contact springs within the socket, so that, when the sliding member is in an unlocked position, the pins can be inserted through these holes without contact with the contact springs, or with minimal contact with these springs. As the sliding member is subsequently moved into its locked position, the contact springs exert high contact forces on the pins from the electronic package. These contact forces are used both to provide for the passage of electrical signals between the individual pins and contact springs and to hold the electronic package in place on the socket.
A heat sink is conventionally clamped atop a high-density electronic package by means of a clamping spring extending upward from the socket into which the electronic package is plugged. A thermally conductive grease aids in the transfer of heat from the electronic package to the heat sink. Heat is dissipated from the heat sink into the surrounding air by means of a number of pins or fins extending outward as a part of the heat sink. A suitable force between the electronic package and the heat sink is maintained by the clamping spring. Many of the high-density pluggable electronic modules requiring a ZIF socket, due to a high pin count, also require this kind of a heat sink for proper operation.
Computing devices are being increasingly used in environments, such as manufacturing environments, including relatively high levels of mechanical shock and vibration. It has been determined that, during operation in such an environment, the detent mechanism used to hold the sliding member within the ZIF socket in its closed position is sometimes inadequate, allowing the sliding member to be moved by shock and vibration from its locked position toward its unlocked position. This movement causes the failure of signal transmission as the forces are reduced between individual spring contacts within the socket and individual pins from the electronic module, and conceivably loosens the electronic module from the socket.
Thus, what is needed is a positive method for positively holding the sliding member in its closed position. Preferably, such a method can accomplish this objective without increasing part count or assembly complexity by performing this latching function as a heat sink is clamped in place atop the electronic module.