52 of the cam member in response to relative rotational motion in a direction indicated by arrows 54 between the cam member and the cam follower the o ring 34 is sized and adapted to mate with the flat surface radially extending flat surface 56 at the intermediate position 42 the cam member 30 compresses the o ring 34 in response to the translational movement of the cam member toward the o ring the compression of the o ring produces frictional torque for resisting the rotational movement of the cam member relative to the cover unit thereby resisting rotational movement of the base unit 12 relative to the cover unit 14 preferably the foldable housing is composed of plastic however many other types of materials can be used preferably the o ring is composed of rubber however other materials having an appropriate coefficient of friction can be used fig4 is a bottom view of the cover unit 14 of the foldable housing 11 shown without the display 18 shown in fig1 fig5 is a right side view of the cover unit 14 showing the attachment post 38 for mating with an attachment gear not shown on the base unit 12 such that there is no relative movement between the cam member 30 and the base unit 12 fig6 is an enlarged bottom view of area 34 6 34 of the frictional hinge mechanism shown in fig4 showing the lobe 50 of the cam follower 32 interacting with the cam surface 44 of the cam member 30 such that there is minimal deflection of the cam member.