Miniature heat sink

DETAILED DESCRIPTION The present invention is concerned with unique self-fastened heat sinks which offer marked advantage in respect of economy of manufacture, ease of installation and use, and promotion of efficient heat transfers, particularly in connection with the cooling of miniature power-tab type semiconductor devices.
In one preferred embodiment, such a heat sink is formed as a unitary stamped-sheet-metal item having three principal portions: first, a relatively shallow trough- or channel-shaped body of substantially rectangular cross-section having an open top; second, a pair of broad-area extensions spreading oppositely outwardly from upper margins of the open-topped body and thence looping back toward the center but terminating just slightly inwardly of the body margins; and, third, bent free ends of the looped-back extensions which slope downwardly and inwardly from above and downwardly and outwardly below to allow a power-tab type device to be pressed into the channel-shaped body from above and to be snap-locked there as the resiliently-deflected ends close onto its upper edges.
Depth of the shallow body portion is selected to be less than that of the thickness of the molded-plastic part of the semiconductor package (such as a TO-220 type package) which it is intended to serve, and the free ends of the looped-back extensions are disposed for engagements with upper edges of the same molded-plastic part, and the overall length of the heat sink is at least about the same as that of the entire semiconductor package, including its tab.
Accordingly, it is one of the objects of the present invention to provide a unique and advantageous heat sink which is especially useful with miniature electronic plastic power packages of the power-tab type, having a channel-shaped sheet-metal body with unitary extensions looped back to form resilient heat-dissipating fins having ends which are yieldably movable to admit a power package into the body and to close over and hold its edges in place.
A further object is to provide a miniature stamped sheet-metal heat sink, for power-tab type semiconductor devices and the like, in which a shallow open-topped body channel receives the tab and plastic package of such a device closely within it from above and snap-fastens it in place via integral looped extensions of margins of the channel which aid in convective dissipation of heat