Security systems

A tumbler arrangement for a combination lock adapted for having its combination changed either by hand or with the use of a key, said tumbler arrangement comprising:

• means for mounting a plurality of tumbler wheels in a stacked relationship for rotation about an axis, each of said tumbler wheels having an inner element releasably engaged with a circumferentially disposed outer element, with each said outer element having a peripheral gate and means for masking said gate;
• means for maintaining said inner and outer elements in an engaged condition for simultaneous rotation under normal tumbler operation;
• a peripherally gated rotatable driver wheel for rotating said tumbler wheels;
• a fence lever having a nose for contact with said driver wheel and a fence for contact with said tumbler wheel;
• means for preventing contact by said fence with the circumferential edges of said tumbler wheels while said tumbler wheels are being rotated;
• means for axially disengaging said stacked inner elements from said stacked outer elements by said key while simultaneously preventing rotational and axial movement of said out element as the disengaged inner elements are rotated to change the combination of said tumbler arrangement said axially disengaging means further includes each said outer element having an opening formed therein for receiving a pin member operable in parallel with said key, said pin member passing through the opening in each said outer element to thereby prevent rotation of said outer elements as said inner elements are disengaged therefrom by said key;
• each said outer element including a plurality of said openings which include holes formed through the thickness of said outer element and disposed radially equidistantly about the rotational axis of said outer element for symmetry and balance.