Flow rate adjusting device

A flow rate adjusting device comprising:

• a flow channel member having a flow channel and a female screw portion formed therein, the flow channel configured and arranged for air to flow therethrough to a cylinder of a door;
• and
• a valve mechanism for adjusting a ratio of opening of the flow channel,
• wherein the valve mechanism includes:
• a rod extending in a traverse direction traversing the flow channel, the rod having a male screw portion configured to be threaded with the female screw portion of the flow channel member, the rod being movable in the traverse direction when rotated on an axis extending along the traverse direction, so that the rod touches or separates from a valve seat formed on an inner surface of the flow channel;
• a knob attached to a portion of the rod that is outside the flow channel member, the knob being integrally rotatable with the rod and being movable in the traverse direction relative to the rod;
• and
• a lock mechanism having an engaging portion and a to-be-engaged portion, the engaging portion protruding from one of the flow channel member and the knob, the to-be-engaged portion being formed in the other of the flow channel member and the knob and configured to be engaged with the engaging portion when accommodating the engaging portion therein, and
• wherein the male screw portion of the rod is fastened by the female screw portion of the flow channel member in response to rotation of the knob,
• wherein the engaging portion protrudes from the flow channel member in the traverse direction,
• wherein the to-be-engaged portion is a depression in a surface of the knob facing the flow channel member and depressed in the traverse direction,
• wherein the engaging portion is engaged with the to-be-engaged portion in a circumferential direction around the axis when the knob is in a prohibited state,
• wherein a plurality of the engaging portions and a plurality of the to-be-engaged portions are arranged in the circumferential direction,
• wherein the number of the to-be-engaged portions is greater than the number of the engaging portions, and
• wherein the lock mechanism is switched by the knob moving in the traverse direction between (i) the prohibited state in which the engaging portion is engaged with the to-be-engaged portion so that the rotation of the rod relative to the flow channel member is prohibited via the knob and (ii) a permitted state in which the engagement between the engaging portion and the to-be-engaged portion is undone so that the rod is permitted to rotate relative to the flow channel member.