In some embodiments, a heat sink is pressed down on a heat source such as an integrated circuit by rotating a cam to press down a set of springs over a loading arm, which is in turn positioned over a heat sink base. A cam shaft is placed in a hinge opening of a mounting frame secured to a printed circuit board (PCB). The mounting frame encloses a heat sink positioned over an IC. The hinge opening defines a hinge axis parallel to the PCB plane. A loading arm includes spring wells for holding coil springs, which are compressed between the mounting frame and the bottoms of the spring wells when the cam is rotated. The mounting frame and loading arm may include mating, self-locking sections including hinge protrusions having cross-sections shaped as a circle sectioned linearly off-center.