Heavy duty stapler

A heavy duty stapler comprising:

• a base member;
• a magazine member, which has a first end pivotally connected to the base member and a second end opposite to the first end, including a firing device provided at the second end thereof, with a firing portion formed from an end of the firing device;
• a lever arm, which has first and second end, including first and second pivotal sections defined at the first end thereof and a pressing section defined at the second end thereof opposite to the first and second pivotal sections, with the first pivotal section pivotally connected to the base member;
• a linkage member having a first end pivotally connected to the second pivotal section of the lever arm and a second end opposite to the first end thereof, with the whole length of the linkage member being able to be perpendicular to a direction of the first end of the lever arm from the first pivotal section to the second pivotal section;
• and
• a driven member including a first pivotal portion pivotally connected to the base member, a second pivotal portion pivotally connected to the second end of the linkage member and a driven portion, with a direction of the driven member from the first pivotal portion to the second pivotal portion being able to be perpendicular to the whole length of the linkage member.