High-pressure card locks for maximizing heat transfer from electronics cards to card cages
Card locks for securing electronics card in card slots within cages and designed and configured to allow each card lock to impart high uniform pressure between an electronics card and the corresponding card slot to maximize heat transfer from the electronics card to the card cage to efficiently sink heat generated onboard the electronics card. In some embodiments, a high-pressure card lock of the present disclosure has a pair of low-angle wedges and a locking mechanism that effectively pushes one of the wedges along the other wedge to put the high-pressure card lock into its locked, high-pressure-exerting state. In other embodiments, a high-pressure card lock of the present disclosure has a pair of low-angle wedges and a locking mechanism that effectively draws one of the wedges along the other wedge to put the high-pressure card lock into its locked, high-pressure-exerting state.
1. A card lock for locking an electronics card into a card cage, the card lock comprising:
a first wedge that tapers in thickness from a first end to a second end;
a second wedge that tapers in thickness from a third end to a fourth end, wherein the second wedge is located so that the third end is located proximate to the second end of the first wedge; and
a locking mechanism that includes:
a fixed portion fixedly secured to the first wedge at the second end of the first wedge; and
a pusher engaged with each of the fixed portion and the second wedge, the pusher designed and configured to act against the fixed portion to push the second wedge along the first wedge so as to expand the card lock;
wherein:
each of the first and second wedges has a taper in a range of 1° to 3°;
the first wedge includes a first inclined face and the second wedge includes a second inclined face engaging the first inclined face in sliding contact at a frictional interface having a friction coefficient of 0.1 or less; and
the friction coefficient and the taper contribute to the card lock having a force multiplier of at least 6 as between a compressive force applied by the pusher to the second wedge and a compressive force applied by the first and second wedges to a card-lock channel of an electronics card cage.
2. A card lock according to claim 1 , wherein the first wedge includes a first inclined face and the second wedge includes a second inclined face designed and configured to sliding engage the first inclined face, the card lock further comprising a retainer extending between the first and second inclined faces and designed and configured to inhibit relative lateral movement between the first end of the first wedge and the fourth end of the second wedge.
3. A card lock according to claim 1 , wherein the first wedge includes a first inclined face and the second wedge includes a second inclined face designed and configured to engage the first inclined face in sliding at a frictional interface, at least one of the first and second inclined faces including a low-friction coating at the frictional interface.
4. A card lock according to claim 1 , wherein each of the first and second wedges is substantially solid.
5. A card lock according to claim 4 , wherein each of the first and second wedges is made of a material having a thermal conductivity of less than 200 W/mK.
6. A card lock according to claim 5 , wherein the thermal conductivity is less than 100 W/mK.
7. A card lock according to claim 6 , wherein the thermal conductivity is less than 25 W/mK.
8. An assembly, comprising:
a chassis having at least one card slot having a thermally conductive sidewall;
an electronics card having a length, the electronics card engaged in the at least one card slot so as to be in contact with the thermally conductive sidewall along the length of the electronics card; and
a card lock according to claim 1 , wherein the card lock is engaged in the at least one card slot so as to force the electronics card into firm contact with the thermally conductive sidewall so that pressure of the electronics card against the thermally conductive sidewall is at least 85 psi (0.59 MPa) along substantially the entire length of the portion of the card lock in contact with the electronics card.
9. An assembly according to claim 8 , wherein the pressure is at least 350 psi (2.41 MPa).
10. An assembly according to claim 9 , wherein the contact of the card lock with the electronics card has a pressure uniformity of at least 0.8.
11. An assembly according to claim 9 , wherein the contact of the card lock with the electronics card has a pressure uniformity of at least 0.9.
12. An assembly according to claim 8 , wherein the pressure is at least 1000 psi (6.90 MPa).
13. An assembly according to claim 12 , wherein the contact of the card lock with the electronics card has a pressure uniformity of at least 0.7.
14. An assembly according to claim 12 , wherein the contact of the card lock with the electronics card has a pressure uniformity of at least 0.8.
15. An assembly according to claim 12 , wherein the contact of the card lock with the electronics card has a pressure uniformity of at least 0.5.
16. An assembly according to claim 12 , wherein the contact of the card lock with the electronics card has a pressure uniformity of at least 0.65.
17. An assembly according to claim 8 , wherein the pressure is at least 1400 psi (9.65 MPa).