Mailbox with lockable letter mail compartment for use in motorized delivery routes

Claim 1

In a rural-type mailbox having a flat rectangular floor, a short back plate, side walls extending no higher than the back plate, and a cover that may be formed by extending the side wall on one side over to the side wall on the other side in a form which conforms to the shape of the back plate, said side walls being flat over at least an initial part extending up from said floor, and a hinged door opposite said back plate, said hinged door conforming to the shape of said back plate to fit the opening between said side walls and between the floor and the cover, the combination of a lockable box inside of said rural-type mailbox for receiving letter mail, said lockable box being comprised of a flat rectangular bottom, flat rectangular sides extending from said bottom to a height less than the height of said back plate of said rural-type mailbox, a top, and a front closure at one end, said lockable box closely fitting inside said rural-type mailbox with the closure thereof placed just behind said hinged door of said rural-type mailbox, a slot in said lockable box through which letter mail may be inserted, said closure comprising a hinged door through which letter mail may be removed from said lockable box, and said hinged door of said lockable box having a key-operated mechanism for locking, and means for securing the bottom of said close fitting lockable box to the floor of said rural-type mailbox with said slot and hinged door of said lockable box accessible through said hinged door of said rural-type mailbox for insertion and removal of letter mail.