Cup washer for a fastener

An assembly comprising:

• a fastener having an elongated shank having a proximate end and a distal end, the proximate end including a head;
• a nut adapted to be fitted onto the distal end of the shank and to be secured thereonto;
• a washer fitting onto the shank between the head and the nut, the washer having an inner portion and an outer portion joined by a substantially perpendicular connecting wall, the inner portion and the connecting wall forming a cavity and the outer portion extending outwardly from the connecting wall to form a flange, the inner portion having a washer opening formed therein;
• a first plate having a first plate aperture adapted to accept the distal end of the fastener and to accommodate the inner portion of the washer therein, the first plate aperture being larger than an outer diameter of the substantially perpendicular connecting wall and smaller than an outer diameter of the flange to define a gap between the first plate and the substantially perpendicular connecting wall;
• and
• a second plate having a second plate aperture adapted to accept the distal end of the fastener, wherein the first plate and the second plate are joined together between the flange and the nut with the inner portion of the washer interposed_between the head of the fastener and the nut
• wherein the first plate and the second plate each have an inner plate surface and an outer plate surface with the inner plate surfaces facing each other and the outer plate surfaces facing outwardly, and wherein at least a portion of the flange of the washer and the outer surface of the first plate overlap and interact to permit relative movement.