Dispensing closure

A dispensing closure for a system having an opening between an exterior of the system and an interior of the system where a fluent substance may be stored, said dispensing closure comprising:

• A. a closure body that
• 1) can be located at the system opening and that defines a lower end for communicating with the system,
• 2) has an upper end, and
• 3) has a body flow passage to accommodate the flow of a fluent substance through said closure body;
• B. an actuator that
• 1) is rotatably mounted to said closure body for occluding said body flow passage to prevent flow of a fluent substance through said dispensing closure when said actuator is in a closed, non-dispensing position and for permitting flow of a fluent substance through said dispensing closure when said actuator is rotated to an open, dispensing position,
• 2) includes a dispensing flow passage having an inlet end that is in communication with said body flow passage and having an outlet end which permits dispensing through said actuator in said open, dispensing position, and
• 3) includes a back region opposite said outlet end and having a central cam element for frictionally engaging said closure body to maintain said actuator in said open, dispensing position, and said back region includes at least one rib located adjacent said central cam to resist said actuator from moving into said open, dispensing position, said at least one rib having an initial configuration prior to movement of said actuator into said open, dispensing position and said at least one rib having a permanently deformed configuration after movement of said actuator into said open, dispensing position.