Ceiling recessed-type lamp unit

A ceiling recessed-type lamp unit designed to be recessedly mounted in an opening formed in a ceiling, comprising:

• a unit body adapted to be recessed in the ceiling;
• a support member fixed to said unit body;
• an engagement member supported by said support body in a vertically movable manner and in a rotatable manner about a vertical axis of said engagement member;
• and
• an elastic member which applies a downward biasing force to said engagement member,
• wherein:
• said support member is composed of a single piece of plate which is a separate component from said unit body, and formed with a latch portion adapted to engage said engagement member, and a guide slot successively extending from said latch portion downwardly, said support member being adapted to adjustably change a vertical fixing position thereof relative to said unit body;
• and
• said engagement member is composed of a single piece of bar which has an intermediate portion bent in a U shape to serve as a first engagement portion engageable with said latch portion of said support member, and a distal end bent to serve as a second engagement portion engageable with a back surface of the ceiling, said engagement member being adapted to be moved upwardly along said guide slot against the downward biasing force of said elastic member and then rotated in a first direction about said vertical axis, so that said first engagement portion is latchedly engaged with said latch portion to allow said engagement member to be set in a non-engagement position where said second engagement portion is retracted to extend along a lateral surface of said unit body so as to avoid engagement with the back surface of the ceiling, said engagement member being adapted, when it is in said non-engagement position, to be rotated in a second direction opposite to said first direction to release said engagement between said first engagement portion and said latch portion, so that said engagement member is moved downwardly along said guide slot by the downward biasing force of said elastic member, and set in an engagement position where said second engagement portion is positioned to protrude laterally outwardly from said unit body and engaged with the back surface of the ceiling, wherein said first engagement portion in said engagement position is located in said guide slot in such a manner as to have interference with a surface of said support plate defining said guide slot to maintain said engagement position.