Lock apparatus for opening/closing member

A lock apparatus for an opening/closing member which is installed in an opening portion in an installation base member so as to be opened and closed, including:

• a housing which is attached to one of the installation base member and the opening/closing member;
• a rotor which is attached rotatably to the housing;
• a rod which is attached to the rotor so as to slide in an interlocked fashion with the rotor and so as to be engaged with or disengaged from an engagement portion provided on the other one of the installation base member and the opening/closing member;
• a bearing portion which is provided on the rotor;
• a return spring which rotationally biases the rotor directly or via the rod so that the rod is engaged with the engagement portion;
• a knob which is attached rotatably to the housing and which has a holding portion at one end thereof;
• and
• a presser element which is formed at the other end of the knob so as to overlap the bearing portion with a predetermined overlap width and which presses on the bearing portion upon pulling of the knob so as to rotate the rotor against a biasing force of the return spring to thereby pull the rod out of the engagement portion,
• wherein, with the rod kept engaged with the engagement portion, a rotating center of the knob is positioned closer to the holding portion of the knob than a contact point between the bearing portion and the presser element,
• wherein the knob includes a front wall and a pair of side walls which project from both sides of the front wall toward the housing,
• wherein an arc-shaped groove is formed in the pair of side walls, a center of the arc-shaped groove being provided close to a front surface of the front wall,
• wherein an arc-shaped projection or plural pin-shaped projections are formed on the housing so as to be inserted into the arc-shaped groove, and
• wherein the knob rotates about the center of the arc-shaped groove as a rotating center.