Covering device for nut and covering device for bolt head

A nut covering device for covering a nut member screwed onto a bolt, in order to prevent rotation of said nut member, comprising:

• a cover assembly, comprising:
• an inner cover, which fits around, in a rotatable manner, at least a portion of said nut member;
• an outer cover, which fits around said inner cover in a manner allowing for relative rotation and can cover an outer perimeter of said nut member;
• and a first constraining mechanism, which constrains so that there is no relative motion of said outer cover with respect to said inner cover in an axis direction;
• a second constraining mechanism, which constrains so that there is no relative motion of said inner cover with respect to said nut member in said axis direction;
• a third constraining mechanism, which constrains so that there is no relative motion of said outer cover with respect to said nut member in said axis direction in at least a direction of removal;
• said second constraining mechanism is constructed so that, when said inner cover matches a specified phase with respect to said nut member, said constraint on said inner cover is released;
• said third constraining mechanism is constructed so that, when said phase of said outer cover with respect to said nut member is matched to a second specified phase which is different from said specified phase, said constraint on said outer cover is released.

A bolt head covering device for covering a head of a bolt and preventing rotation of said head bold, comprising:

• a cover assembly, comprising:
• an inner cover, which fits around, in a rotatable manner, at least a portion of said bolt head;
• an outer cover, which fits around said inner cover in a manner allowing for relative rotation and which can cover an outer perimeter of said bolt head;
• and a first constraining mechanism, which constrains so that there is no relative motion of said outer cover with respect to said inner cover in an axis direction;
• a second constraining mechanism, which constrains so that there is no relative motion of said inner cover with respect to said bolt head in said axis direction;
• a third constraining mechanism, which constrains so that there is no relative motion of said outer cover with respect to said bolt head in said axis direction in at least a direction of removal;
• said bolt head covering device is constructed so that said cover assembly is detachable from said bolt head by releasing said second and third constraining mechanisms by matching a circumferential phase of said inner cover and said outer cover with respect to said bolt head with a predetermined specified phase.