Doorknob lock apparatus operable by combination or key

A lock apparatus comprising:

• a dial for entering a combination of numbers by sequenced rotations of said dial;
• a plurality of cam rings for unlocking said lock apparatus when said predetermined combination of numbers is entered, said plurality of cam rings including a first cam ring having a plurality of angularly spaced drive holes facing said dial;
• a drive pin extending from said dial and received within one of said plurality of drive holes to rotatably couple said first cam ring with said dial at a chosen drive orientation that determines said combination;
• and
• biasing means for urging said dial and first cam ring axially together to maintain said rotational coupling;
• said dial being axially separable from said first cam ring against the urging of said biasing means when said lock apparatus is unlocked to permit relative rotation between said dial and said first cam ring;
• whereby said drive orientation can be changed by causing said drive pin to be received within a different one of said plurality of drive holes to change said combination.

A lock apparatus comprising:

• a dial for entering a combination of numbers by sequenced rotations of said dial, said dial having a plurality of angularly spaced drive holes;
• a plurality of cam rings for unlocking said lock apparatus when said predetermined combination of numbers is entered, said plurality of cam rings including a first cam ring having a drive pin extending therefrom and received within one of said plurality of drive holes to rotatably couple said first cam ring with said dial at a chosen drive orientation that determines said combination;
• and
• biasing means for urging said dial and first cam ring axially together to maintain said rotational coupling;
• said dial being axially separable from said first cam ring against the urging of said biasing means when said lock apparatus is unlocked to permit relative rotation between said dial and said first cam ring;
• whereby said drive orientation can be changed by causing said drive pin to be received within a different one of said plurality of drive holes to change said combination.