Patent ID: 7631398

Claim:
A cam device for use in a hinge assembly comprising: a first member including a first engaging side including a radially extended inner section and an outer section extending radially from the inner section, a recessed first engaging portion extending radially on the inner section, a recessed second engaging portion extending radially on the outer section, and recessed third and fourth engaging portions extending radially from the inner section to the outer section; and a second member including a second engaging side including a radially extended inner section and an outer section extending radially from the inner section, a ridged first engaging portion extending radially on the inner section, a ridged second engaging portion extending radially on the outer section, and ridged third and fourth engaging portions extending radially from the inner section to the outer section; wherein the ridged first, second, third and fourth engaging portions are adapted to be completely received in the recessed first, second, third, fourth engaging portions, respectively, and the ridged first engaging portion is prevented from locating in any of the recessed engaging portions other than the recessed first engaging portion, and the second ridged engaging portion is prevented from locating in any of the recessed engaging portions other than the second engaging portion; wherein the ridged first, second, third and fourth engaging portions are adapted to be partially received in the recessed first, second, third, fourth engaging portions respectively, and when the ridged first and second engaging portions are partially disposed in the recessed first and second engaging portions respectively, a first contacted area between the ridged third engaging portion and the recessed third engaging portion plus a second contacted area between the ridged fourth engaging portion and the recessed fourth engaging portion is substantially equal to two times a third contacted area between the recessed first engaging portion and the ridged first engaging portion plus a fourth contacted area between the recessed second engaging portion and the ridged second engaging portion to preclude the cam device from suffering an increased pressure.