Fastener assembly and method for heat sink mounting
View Patent ↗Method and assembly for attaching a heat sink to a heat source surface associated with a printed circuit board or other component having a heat source. A fastener assembly may include a push pin with a barbed, bifurcated end arranged to be inserted through an opening of the printed circuit board and thereby secure the heat sink to the printed circuit board. A stopper may be headless, be separable from the push pin, and have a portion, such as a barrel-shaped element, positionable in a throughbore of the push pin that supports the bifurcated end so that movement of the barbed portions toward each other is resisted, thereby securing engagement of the barbed portions with the printed circuit board.
1. A fastener assembly for use in securing a heat sink to a component having a heat source, the fastener comprising:
a metal push pin having an elongated body with a bifurcated distal end and a throughbore extending longitudinally through the elongated body, the bifurcated distal end including a pair of movable portions that are movable to flex toward and away from each other and arranged to engage at a hole of the component; and
a stopper having a barrel that is sized to fit within, and be movable longitudinally in, the throughbore, the stopper being separable from the push pin, wherein the stopper is headless, is arranged to be positioned completely within the throughbore of the push pin by pushing the stopper into the throughbore, and includes a plurality of circumferential ribs on the barrel or a longitudinal groove on an outer surface of the barrel to make the stopper radially compliant,
wherein with a portion of the stopper positioned in the throughbore at the bifurcated distal end, the movable portions are prevented from moving toward each other.
2. The fastener assembly of claim 1 , wherein the bifurcated end includes a barb on each of the movable portions, the barbs being arranged to engage with a surface of the component at the hole.
3. The fastener assembly of claim 1 , wherein the elongated body includes a slot or groove through the body to form the bifurcated end.
4. The fastener assembly of claim 1 , wherein the push pin includes a head at an end of the elongated body opposite the bifurcated end.
5. The fastener assembly of claim 1 , wherein the stopper includes a bifurcated end at a distal end of the barrel arranged to support the bifurcated end of the push pin.
6. The fastener assembly of claim 1 , wherein the stopper includes a plurality of circumferential ribs on the barrel and a longitudinal groove to make the stopper radially compliant.
7. A heat source and heat sink assembly, comprising:
a heat source attached to a component having one or more openings, the heat source having a heat transfer surface;
a heat sink having a heat receiving surface in contact with the heat transfer surface and a fastener engaging portion; and
at least one fastener assembly engaged with the fastener engaging portion of the heat sink and an opening of the component, the at least one fastener including:
a metal push pin having an elongated body with a bifurcated distal end and a throughbore extending longitudinally through the elongated body, the bifurcated distal end including a pair of movable portions that are movable to flex toward and away from each other and arranged to be inserted into and engage at the opening of the component; and
a stopper having a barrel that is sized to fit within, and be movable longitudinally in, the throughbore, the stopper being separable from the push pin, wherein the stopper is headless, is arranged to be positioned completely within the throughbore of the push pin by pushing the stopper into the throughbore, and includes a plurality of circumferential ribs on the barrel or a longitudinal groove on an outer surface of the barrel to make the stopper radially compliant,
wherein with a portion of the stopper positioned in the throughbore at the bifurcated distal end, the movable portions are prevented from moving toward each other to maintain engagement of the bifurcated end with the opening.
8. The assembly of claim 7 , wherein the bifurcated end includes a barb on each of the movable portions, the barbs being arranged to engage with a surface of the component at the opening through which bifurcated end is inserted.
9. The assembly of claim 7 , wherein the elongated body includes a slot or groove through the body to form the bifurcated end.
10. The assembly of claim 7 , wherein the push pin includes a head at an end of the elongated body opposite the bifurcated end.
11. The assembly of claim 7 , wherein the stopper includes a bifurcated end at a distal end of the barrel arranged to support the bifurcated end of the push pin.
12. The assembly of claim 7 , wherein the stopper includes a plurality of circumferential ribs on the barrel and a longitudinal groove to make the stopper radially compliant.
13. A method for engaging a heat source with a heat sink assembly, comprising:
providing a heat source attached to a component having one or more openings, the heat source having a heat transfer surface;
positioning a heat receiving surface of a heat sink in contact with the heat transfer surface;
engaging a metal push pin with a fastener engaging portion of the heat sink;
inserting a bifurcated distal end of the push pin through an opening of the component to attach the heat sink to the component, the bifurcated distal end including a pair of movable portions that flex toward each other during insertion of the bifurcated end through the opening; and
inserting a stopper that is separable from the push pin into a throughbore of the push pin by pushing the stopper into the throughbore so as to position a portion of the stopper in the throughbore at the bifurcated distal end of the push pin, positioning of the portion of the stopper in the throughbore at the bifurcated distal end preventing movement of the movable portions toward each other to maintain engagement of the bifurcated end with the opening of the component, wherein the stopper is headless, is arranged to be positioned completely within the throughbore of the push pin, and includes a plurality of circumferential ribs on the barrel or a longitudinal groove on an outer surface of the barrel to make the stopper radially compliant.
14. The method of claim 13 , wherein the step of inserting a bifurcated end includes flexing the movable portions away from each other once barbs on the movable portions pass through the opening, flexing of the movable portions away from each other causing the barbs to engage with a surface of the component at the opening.
15. The method of claim 13 , wherein the step of inserting a stopper includes causing the portion of the stopper positioned at the bifurcated end to urge the movable portions away from each other.
16. The method of claim 13 , wherein the bifurcated end includes a barb on each of the movable portions, the barbs being arranged to engage with a surface of the component at the opening through which bifurcated end is inserted.
17. The method of claim 13 , wherein the push pin includes an elongated body with a slot or groove through the body to form the bifurcated end.
18. The method of claim 13 , wherein the push pin includes a head at an end opposite the bifurcated end.
19. The method of claim 13 , wherein the stopper includes a plurality of circumferential ribs on a barrel and a longitudinal groove to make the stopper radially compliant.