Pivoting arm door lock mechanism

A door safety lock mechanism comprising:

• (a) an arm holding plate attached to a door jamb;
• (b) a pair of arm members, each having a slot therethrough, affixed together such that said slots are in alignment with each other to form a slotted arm;
• (c) pivoting means to pivotally attach said slotted arm to said arm holding plate such that said arm pivots, in a generally vertical plane, from a first position wherein it is generally vertical, to a second position wherein it is generally horizontal;
• (d) a bolt sleeve attached to a door adjacent to said slotted arm holding plate;
• (e) a slidable bolt, slidably retained in said bolt sleeve so as to move from a first position wherein it is disengaged from said slotted arms thereby allowing the door to be opened and closed in a normal manner, and a second position wherein a portion of said bolt passes through said slot in said slotted arm when said slotted arm is in its first position thereby locking said door in a closed position, and to permit a partial opening of said door when said slotted arm is in its second position, the vertical dimension of said portion of said slidable bolt that passes through said slot being greater than the width of said slot;
• and
• (f) a bolt stop pivotally attached to the distal end of said slotted arm between said arm members and being pivotable between a first position wherein it extends across the slot in said arm thereby limiting travel of said bolt along said slot, and a second position wherein it does not extend across said slot, thereby permitting unencumbered movement of said bolt along said slot.