Patent ID: 7729122

Claim:
A fastener for heat sinks, said fastener comprising: a rod including a pressing section, and a rod body which extends downwardly from the pressing section, said rod body having a first engaging member thereon; and a sleeve including opposite upper and lower ends, a bore that extends downwardly from the upper end of the sleeve toward the lower end of the sleeve, a second engaging member engageable with the first engaging member when the rod body is inserted into the bore to prevent said rod from detaching from said sleeve, and a third engaging member at the lower end of the sleeve and below the second engaging member for engaging a substrate; wherein the lower end of the sleeve is deformable to be passable through a through hole in the substrate; when the rod body is inserted into the bore with the first and second engaging members engaging each other, the rod body maintains the lower end of the sleeve in an expanded configuration for causing the third engaging member to engage the substrate and preventing the sleeve from detaching from the substrate; said first engaging member comprises a circular groove on a lower part of the rod body; the upper end of the sleeve comprises a flange; and the lower end of the sleeve comprises a bearing section having a protuberance at an inner side to define the second engaging member corresponding to said circular groove, an engaging recess defining the third engaging member, and a gradually decreasing conical member below said engaging recess.