Bearing pieces are formed on both sides of the rear end of a clincher arm which includes a clincher table for bending a staple at the front end thereof. A magazine member to which staples are loaded and a driver arm for driving out a staple fed from the magazine member are pivotally mounted on an axle, which is provided at the rear ends of the bearing pieces. A handle member is rotatably disposed above the driver arm. A rotation supporting shaft of the handle member is provided at a position somewhat closer to the front than the axle of the bearing pieces. A pin, which is provided at a position closer to the front than the rotation supporting shaft of the handle member, is inserted into an elongated hole formed in each side plate of the driver arm.

A stapler comprising a base defining a horizontal plane, a cartridge assembly coupled to the base at a cartridge attachment point, the cartridge assembly including a ram, and a lever arm pivotally coupled to the base at a lever pivot axis. The lever arm includes a grip for receiving a manual input from a user, and the lever arm is coupled to the ram at a ram input in order to provide a drive force. The stapler includes an inherent force factor, calculated as the horizontal distance from the lever pivot axis to the end of the lever arm divided by the horizontal distance from the lever pivot axis to the ram input, of at least 3.8. Preferably, the lever arm defines an effective lever axis that is at least about 65.degree. offset from the ram axis when in the static position. When stapling, the effective lever axis is preferably offset greater than about 95.degree. when the lever arm is compressed to the fully stapled position.

A stapling operation can be performed with a comparatively small force. The stapler includes a base frame with a support element, and an operation frame pivotally attached to the support element through a main shaft. A staple pressure lower plate is disposed at the operation frame and drives staples stored in a staple magazine upon rotation of the operation frame. The stapler further includes a handle frame at an upper part of the operation frame pivotally attached to the support element such that a rear end part of the operation frame is located above the main shaft. An intermediate element is pivotally attached at one end to the handle frame. The other end of the intermediate element is pivotally attached to the operation frame.

A desktop stapler uses a spring to store energy to install staples by impact blow. The force required to fasten papers together is reduced. A very compact mechanism is used, including a dual coil power spring with a nested lever. A multi function base provides a sloped front all the way to down to a desk top surface to guide paper sheets atop the base, easy access for lifting the stapler off a desk, horizontal or vertical resting positions, and integrated soft grip under-surface. The base surrounds the rear of the stapler body to provide a smooth exterior so that the device is natural to use both horizontally and vertically. A simple re-set spring provides a smooth re-set action as the handle is raised. A staple track includes enlargement features to fit a larger staple pusher spring.

A forward acting stapler includes a unique linkage for driving a firing lever. The linkage includes two links which are each connected to the trigger lever by a roller. The roller is movable within a spot in the trigger lever. As the handle is driven, the two links cause the triggering level to pivot. As the trigger lever pivots it lifts a plunger against a spring force. At some point, the trigger portion releases the plunger allowing the plunger to be returned by the spring force by a staple.