Key top attachment structure

A key top attachment structure for attaching a key top to a casing of a small-sized electronic equipment having a circuit board with a switch mounted thereon, said structure comprising:

• a casing including a spring of a cantilever structure with a rectangular hole, a pair of first and second lock portions provided on opposite sides with respect to said spring, and a third lock portion partially covering said rectangular hole on a fixed end side of said spring;
• and
• a key top including a pressure reception surface adapted to be pressed by a finger, first and second stoppers opposite from said pressure reception surface, a protrusion portion having a third stopper, a first protrusion, and a second protrusion, and a third protrusion;
• wherein:
• said second protrusion temporarily abuts against said spring;
• said protrusion portion is inserted through said rectangular hole;
• said first, second and third stoppers are made to abut against said first, second and third lock portions correspondingly;
• said third protrusion is made to abut against a head of said spring;
• and
• said first protrusion is made to face said switch provided under s a id rectangular hole so as to push down said switch.

An inter-call receiver comprising:

• a circuit board with a switch mounted thereon;
• a key top for depressing said switch;
• and
• a casing accommodating said circuit board and holding said key top, wherein:
• said casing includes a spring and a plurality of lock portions;
• said key top includes a protrusion for pushing down said spring when said key top is attached to said casing from the outside of said casing, and a plurality of stoppers locked in said lock portions, respectively, so that said key top is prevented from being taken off from the outside of said casing;
• and
• said key top is held by said spring and said lock portion.

An inter-call receiver comprising:

• a circuit board with a switch mounted thereon;
• a key top for depressing said switch;
• and
• a casing accommodating said circuit board and holding said key top, wherein:
• said casing includes a spring of a cantilever structure with a rectangular hole, a pair of first and second lock portions provided on opposite sides with respect to said spring, and a third lock portion partially covering said rectangular hole on a fixed end side of said spring;
• said key top includes a pressure reception surface adapted to be pressed by a finger, first and second stoppers opposite from said pressure reception surface, a protrusion portion constituted by a third stopper, a first protrusion, and a second protrusion, and a third protrusion, wherein:
• a second protrusion temporarily abuts against said spring;
• said protrusion portion is inserted through said rectangular hole;
• said first, second and third stoppers are made to abut against said first, second and third lock portions correspondingly;
• said third protrusion is made to abut against a head of said spring;
• and
• said first protrusion is made to face said switch provided under said rectangular hole so as to push down said switch.

An inter-call receiver comprising:

• a circuit board with a switch mounted thereon;
• a key top for depressing said switch;
• and
• a casing accommodating said circuit board and holding said key top, wherein:
• said casing includes a spring and a lock portion;
• said key top includes a protrusion for pushing down said spring when said key top is attached to said casing from the outside of said casing in a first direction, and a stopper locked in said lock portion when said key top is slid along said case in a second direction perpendicular to said first direction;
• and
• said protrusion is engaged with said spring when said key top is slid along said case in said second direction, thereby preventing said key top from being slid in a third direction opposite from said second direction.