Heat sink clip assembly

A pre-assembled heat sink assembly comprising:

• a heat sink defining a fastening hole;
• at least a clip assembly including:
• a sleeve member defining a central bore, a lower portion defining a plurality of outwardly expandable fingers, an upper portion extending through the fastening hole, and a shoulder formed between the upper portion and the lower portion;
• a nail member received within the bore of the sleeve member, said nail member including a cap, a post extending downwardly from the cap, a bottom portion positioned below the post adapted to move downwardly to engageably expand the corresponding fingers;
• and
• an elastic member fitting over the sleeve and positioned between the cap and a top surface of the heat sink, and adapted to exert a resilient force along an axial direction of the clip assembly;
• wherein
• an engagement is formed between the nail member and the sleeve member for preventing the sleeve member from moving downwardly away from the nail member, and thus the shoulder abuts against a bottom surface of the heat sink by means of said elastic member.

An electrical assembly comprising:

• a pre-assembled heat sink assembly including;
• a heat sink defining a fastening hole;
• at least a clip assembly pre-assembled to the heat sink, said clip assembly including:
• a sleeve member extending through the fastening hole and out of a bottom surface of the heat sink;
• a nail member coaxially moved relative to the sleeve member with a cap at a top portion and means for upwardly engaging the sleeve member below said cap to have the nail in an upper position with regard to the sleeve member;
• and
• an elastic member compressed and positioned between the cap and a top surface of the heat sink so as to hold the clip assembly stable in position with regard to the heat sink.

A two-stage electrical assembly comprising:

• a pre-assembled heat sink assembly including:
• a heat sink with a fastening hole;
• at least a clip assembly pre-assembled to the heat sink, said clip assembly including:
• a sleeve member with a coaxially moveable nail member and a spring deflectable along the same axial direction;
• said assembly defining a first stage assembling in which
• the nail member is in a high position relative to the sleeve member with the spring less deflected when the clip assembly is pre-assembled to the heat sink where the sleeve member extends through the fastening hole and is engaged with a bottom surface of the beat sink.

A method for assembling a heat sink to a printed circuit board, comprising the steps of:

• providing a heat sink defining a fastening hole therein;
• providing at least a clip assembly including a sleeve member, a nail member and a spring;
• positioning the sleeve member extending through the fastening hole and below a bottom surface of the heat sink;
• positioning the nail member coaxially moveable with regard to the sleeve member with means for temporarily holding the sleeve member in a higher position relative to the heat sink;
• and
• positioning a spring between a top surface of the heat sink and the nail member to exert a first resilient force to hold both the nail member and the engaged sleeve member in a tensional vertical manner relative to the heat sink so as to pre-assemble the clip assembly to the heat sink.

A pre-assembled heat sink assembly comprising:

• a heat sink defining a fastening hole;
• at least a sleeve member upwardly installed to the heat sink from a bottom side of the heat sink, said sleeve member including a lower portion with a plurality outwardly expandable fingers positioned below the bottom side of the heat sink, and an upper portion extending upwardly into the fastening hole and further above an upper side of the heat sink;
• a nail member coaxially downwardly installed into the sleeve member from the upper side of the heat sink, said nail member and said sleeve member being engaged with each other along an axial direction;
• and
• an elastic member positioned over the sleeve member and between the upper side of the heat sink and a top portion of the nail member.

A pre-assembled heat sink assembly comprising:

• a heat sink defining a fastening hole;
• at least a sleeve member including a lower portion with a plurality outwardly expandable fingers positioned below a bottom surface of the heat sink, and an upper portion extending upwardly into the fastening hole and further above an upper surface of the heat sink;
• a nail member coaxially installed into the sleeve member, said nail member including a top portion and a bottom portion, said nail member and said sleeve member being engaged with each other along an axial direction;
• and
• an elastic member positioned over the sleeve member and between the upper surface of the heat sink and the top portion of the nail member;
• wherein
• both the sleeve member, the nail member and the elastic member are pre-assembled to the heat sink before assembled to a printed circuit board having therein a fixing hole in alignment with the fastening hole, and the bottom portion of the nail member is adapted to engageably expand the corresponding fingers outwardly for latchable engagement with a bottom edge of said fixing hole of the printed circuit board when the nail member is depressed to move deep downwardly relative to the sleeve member.