Patent ID: 8800834

Claim:
A fastener driving apparatus for driving a fastener into a workpiece, the fastener driving apparatus comprising: a power source; a control circuit electrically coupled to the power source; a motor electrically coupled to the power source and responsive to the control circuit; a first cylinder; a first piston reciprocally movable within the first cylinder to execute a compression stroke and a return stroke in an operation cycle of driving the fastener into the workpiece, said first piston defining a gas chamber within said first cylinder, said gas chamber capable of accommodating gas therein; a linear motion converter driven by the motor and operationally coupled to the first piston for reciprocally moving said first piston within the first cylinder; a second cylinder pneumatically connected to the first cylinder; a second piston reciprocally movable within the second cylinder; a fastener supply mechanism, the fastener supply mechanism comprising at least one fastener therein, an anvil coupled to the second piston, the anvil capable of striking a fastener from the fastener supply mechanism to drive said fastener into the workpiece; a retention element operatively coupled to the second piston and the anvil, the retention element capable of retaining said second piston and said anvil in a first position until a sufficient force is applied on said second piston or retention element, a gas passageway disposed between the first cylinder and the second cylinder for pneumatically connecting said first cylinder and said second cylinder; and at least one sensor electrically coupled to the control circuit, the at least one sensor configured to detect at least one position of the operation cycle and communicate the detected position of said operation cycle to the control circuit, wherein during the compression stroke, the first piston is configured to move towards a top dead center of the first cylinder for compressing the gas in the gas chamber, the gas passageway communicating the compressed gas to the second cylinder, the retention element retaining the second piston and the anvil in a first position until a sufficient force is applied on said second piston, and upon said sufficient force being applied to said second piston or retention element to overcome the retention force of said retention element, said second piston moving linearly from said first position to a second position, at which second position said anvil may drive a fastener into the workpiece; and wherein during the return stroke the first piston is configured to move towards a bottom dead center of the first cylinder; and wherein the second piston and the anvil are caused to retract to said first position by a retracting means and the retention element thereafter retaining said second piston and anvil in said first position; and wherein during a predetermined point in the operation cycle, based on the at least one detected position by the at least one sensor, the control circuit is configured to stop the operation cycle.