US Patent 9826976 Motor driven surgical instruments with lockable dual drive shafts

Motor driven surgical instruments that include a first rotary drive system and a second rotary drive system. Various forms include a transmission assembly that is selectively shiftable between a first drive position wherein rotary motion generated by the motor is transferred to the first rotary drive system and a second drive position wherein rotary motion generated by the motor is transferred to the second rotary drive system. Various forms further include a locking assembly configured to mechanically prevent rotation of the second rotary drive system when the transmission assembly is in the first drive position as well as to prevent rotation of the first rotary drive system when the transmission assembly is in the second drive position.