Electrical connector assembly having board hold down

1. An electrical connector assembly, comprising:

a mother board;

a card edge connector mounted on the mother board and comprising a housing defining a slot, and a plurality of contacts disposed on at least one side of the slot of the housing and exposed into the slot;

a daughter card comprising a mating edge inserted into the slot of the housing, a plurality of conductive pads on the mating edge for electrically connecting with contacts of the card edge connector; and

a board hold down, which is separated from the card edge connector and mounted on the mother board, holding the daughter card in the card edge connector and keeping the daughter card parallel to the mother board; wherein

the board hold down comprises a body portion supporting the daughter card to keep a predetermined distance between the daughter card and the mother board; wherein

the board hold down comprises a resilient arm and an anti-overstress extending from a first and a second ends of the body portion, respectively.

2. The electrical connector assembly as claimed in claim 1 , wherein the board hold down comprises a locating portion extending upwardly from the body portion, and wherein the daughter card defines an engaging hole engaged with the locating portion of the board hold down.

3. The electrical connector assembly claimed in claim 2 , wherein the locating portion comprises a lead-in formed on a top end thereof for guiding the insertion of the locating portion into the engaging hole of the mother board.

4. The electrical connector assembly as claimed in claim 1 , wherein the board hold down comprises a leg portion extending downwardly from the body portion, and wherein the mother board defines a retention hole receiving the leg portion of the board hold down.

5. The electrical connector assembly as claimed in claim 1 , wherein the anti-overstress portion comprises a main section, and a tab perpendicularly extending from the main section and having an upwardly bent distal end.

6. The electrical connector assembly as claimed in claim 5 , wherein the board hold down comprises a latch portion extending from the resilient arm and locking a rear edge of the daughter card.

7. The electrical connector assembly as claimed in claim 6 , wherein the resilient arm is over the tab of the anti-overstress portion and is deflectable with the latch portion between the main section and the distal end of the tab.

8. An electrical connector assembly, comprising:

a mother board;

a card edge connector mounted on the mother board and comprising a housing defining a slot having an opening at one side of the card edge connector, and a plurality of contacts disposed on at least one side of the slot of the housing and exposed into the slot; and

a board hold down mounted on the mother board, said board hold down being separated from and located beside the one side of card edge connector, the board hold down and the slot of housing together defining a support plane adapted for supporting a daughter card; wherein

the board hold down comprises an arc-shaped body portion, a locating portion extending upwardly from the body portion, a pair of leg portions extending downwardly from the body portion, a resilient arm extending from a first end of the body portion, and a latch portion extending upwardly from the resilient arm.

9. The electrical connector assembly as claimed in claim 8 , wherein the board hold down comprises an anti-overstress extending from a second end of the body portion, and including a main section and a tab perpendicularly extending from the main section with an upwardly bent distal end, and wherein the resilient arm is over the tab and is deflectable with the latch portion between the main section and the distal end of the tab.

10. An electrical connector assembly comprising:

a first circuit board;

a card edge connector mounted to the first circuit board and defining a slot with a plurality of contacts within said slot;

a second circuit board having a front edge section angularly inserted into the slot and downwardly rotated toward the first circuit board until reaching a parallel relation with the first circuit board; and

at least one deflectable board holder mounted to the first circuit board; wherein said board holder is located around a rear edge section of the second circuit board, and downwardly presses said rear edge section; wherein

said board holder includes a body portion, a locating portion upwardly extending from the body portion for supporting the second circuit board, a resilient arm and an anti-overstress portion respectively extending from opposite ends of the body portion of the board holder.

11. The assembly as claimed in claim 10 , wherein a latch portion upwardly extends from the resilient arm and downwardly presses the rear section of the second circuit board.

12. The assembly as claimed in claim 10 , wherein the anti-overstress comprises a main section facing the resilient arm, and a tab extending from the main section and beyond the resilient arm.

13. The assembly as claimed in claim 12 , wherein the resilient arm is restrainedly moveable between the main section and the tab of the anti-overstress portion.