Cam mechanism for a zero-insertion-force connector

Claim 1

A zero-insertion-force connector for connecting an electrical component to a substrate, comprising: a base having a main body defining a number of holes which receive a corresponding number of contacts therein, the contacts adapted to be electrically connected to the substrate; a cover slidably mounted on the base between open and closed positions, at whereby the open position, pins of the electrical component extend into the holes of the base via the cover and are disengaged from the contacts, and at the closed position, the pins are engaged with the contacts; a cam mechanism for moving the cover relative to the base between the open and closed positions, said cam mechanism comprising: a cam having a head rotatably received in the cover for receiving a rotation force, a body located below the head and defining first and second positioning indices, said body having a bottom face with a portion supported by the cover; and a locating device having a third positioning index; where when the cam is rotated to a first position wherein the third positioning index engages with the first positioning index, the body of the cam moves the cover relative to the base to reach the open position, and wherein when the cam is rotated to a second position where the third positioning index engages with the second positioning index, the body of the cam moves the cover relative to the base to reach the closed position; wherein the locating device is a cantilever integrally formed with the base, the third positioning index being a bulge formed on a free end of the cantilever; wherein the first and second positioning indices are first and second depressions formed on the body of the cam, whereby at the first position, the bulge is fited within the first depression, and at the second position, the bulge is fitted within the second depression; wherein the first and second depressions are angularly spaced from each other by ninety degrees; wherein the cover comprises first and second lugs extending from a main body of the cover over the main body of the base, and a stud connects the lugs, a side of the main body of the cover located between the lugs, the lugs and the stud cooperatively defining a first cam receiving space therebetween; wherein the head of the cam is round in shape and has a rotation center, the body of the cam having a circumferential periphery comprised of at least first and second arcs generally opposite to each other, the first arc has a curvature center coincident to the rotation center of the head and a curvature radius R1, the second arc having a curvature center offset from the rotation center of the head and a curvature radius R2 which is larger than R1.