Suspended load backpack

A suspended load backpack, comprising:

• a moving frame including a bag for receiving a load to be carried by the backpack;
• a fixed frame including shoulder straps for holding the fixed frame in place on a wearer's back;
• a rail assembly that connects the moving frame to the fixed frame but allows the moving frame to move relative to the fixed frame;
• a mounting wheel connected to the fixed frame;
• a compliant mechanism that is connected between the fixed frame and the moving frame and wrapped around the mounting wheel to permit movement of the moving frame relative to the fixed frame during a gait of the wearer of the backpack in accordance with tension on the compliant mechanism;
• a ratchet assembly including a lever that rotates the mounting wheel to apply tension to the compliant mechanism to adjust a spring constant of the compliant mechanism;
• and
• a locking mechanism that locks the moving frame to the fixed frame at a first locking position to prevent movement, the locking mechanism comprising a lock latch connected to the fixed frame via a lock pivot pin that allows the lock latch to swing and to engage a lock recess in the moving frame.