Abstract: A dual backset deadbolt assembly comprises a deadbolt mounted in a deadbolt housing for movement to a locking position or an unlocking position, an extension housing having two parallel side walls which are provided with two cam guide slots located at two different backset distances, a transmission plate means having a front engaging member to connect with the deadbolt and a rear forked portion, the rear forked portion having two rearwardly extending strip members and an elongated opening between the strip members, the strip members having at least one pair of engagement members, the engagement members being formed respectively on the strip members, a single cam member mounted in the extension housing and having at least one spindle slot to be put in an alignment with at least one of the cam guide slots, the cam member having at least one pair of camming members which can engage with the engagement members to actuate the transmission plate.

Abstract: A dual backset latch bolt assembly includes at least one pair of cam members mounted on at least one side plate of a latch housing. The latch bolt assembly is provided with positioning holes and engaging notches so that the assembly can be used in combination with a lock having either positioning female screws or guide plates for attachment. The latch bolt assembly may be arranged such that two pairs of cam members are mounted respectively on two side plates of the housing, thereby permitting the latch assembly to cooperate with a lock having either a single rotary spindle or two rotary spindles which are respectively associated with two parts of the lock operable from the outside and inside of a door.

Abstract: A dual backset deadbolt assembly to be associated with a lock having a rotatable cylinder which has two axially extending crank members for actuating a deadbolt to move in two opposite directions, wherein the deadbolt assembly comprises a deadbolt housing holding a deadbolt, a rear extension housing having two side plates with aligned crank holes therein, a transmission plate having a front end engaging with the deadbolt, and two independently movable axial strip members slideably provided between two side plates on either side of the crank holes provided in the side plates, the strip members being connected to the rear forked portion of the transmission plate and having a plurality of teeth each extending into each crank hole, the strip members being selectable for cooperation with the operative crank member by the engagement of one of the teeth and the operative crank member.