Powered fastener driver
A powered fastener driver includes a first cylinder, a first piston positioned within the first cylinder, a second cylinder in fluid communication with the first cylinder, and a second piston positioned within the second cylinder. The second piston is moveable between a top-dead-center position and a bottom-dead-center position to initiate a fastener driving cycle. A drive blade is coupled to the second piston for movement therewith and a drive mechanism is configured to drive the first piston between the top-dead-center position and at or near the bottom-dead-center position. The drive mechanism includes a crank arm configured to rotate less than 360 degrees in a first direction to complete a first fastener driving cycle and less than 360 degrees in an opposite, second direction to complete a subsequent second fastener driving cycle.
1 . A powered fastener driver comprising:
a first cylinder;
a first piston positioned within the first cylinder, the first piston being moveable between a top-dead-center position and at or near a bottom-dead-center position;
a second cylinder in fluid communication with the first cylinder;
a second piston positioned within the second cylinder, the second piston being moveable between a top-dead-center position and a bottom-dead-center position to initiate a fastener driving cycle;
a drive blade coupled to the second piston for movement therewith; and
a drive mechanism configured to drive the first piston between the top-dead-center position and at or near the bottom-dead-center position, the drive mechanism including a crank arm configured to rotate
less than 360 degrees in a first direction to move the first piston from at or near the bottom-dead-center position and the top-dead-center position and then back to at or near the bottom-dead-center position to complete a first fastener driving cycle to drive a fastener into a workpiece, and
less than 360 degrees in an opposite, second direction to move the first piston from at or near the bottom-dead-center position and the top-dead-center position and then back to at or near the bottom-dead-center position to complete a subsequent second fastener driving cycle to drive another fastener into the workpiece.
2 . The powered fastener driver of claim 1 , further comprising a latch extending between the drive mechanism and the drive blade, wherein the latch is movable between a locked position, in which the latch engages the drive blade to secure the second piston in the top-dead-center position, and an unlocked position, in which the latch disengages the drive blade so the second piston is able to move from the top-dead-center position to the bottom-dead-center position.
3 . The powered fastener driver of claim 2 , further comprising a biasing member configured to bias the latch towards the locked position, wherein the latch includes a recess aligned with the drive blade when the latch is in the unlocked position.
4 . The powered fastener driver of claim 3 , wherein the drive blade includes a slot configured to receive a portion of the latch when the latch is in the locked position.
5 . The powered fastener driver of claim 2 , wherein the drive mechanism includes a cam coupled for co-rotation with the crank arm.
6 . The powered fastener driver of claim 5 , wherein the cam includes a lobe configured to engage the latch to move the latch from the locked position toward the unlocked position.
7 . The powered fastener driver of claim 1 , wherein the crank arm includes a stop surface configured to engage a fixed stop on a housing of the powered fastener driver both prior to and following completion of the first fastener driving cycle.
8 . The powered fastener driver of claim 7 , wherein a rotational speed of the crank arm is reduced before contact with the fixed stop to prevent shearing of the fixed stop.
9 . The powered fastener driver of claim 1 , wherein the second piston is driven from the top-dead-center position to the bottom-dead-center position in response to the movement of the first piston.
10 . The powered fastener driver of claim 1 , further comprising a back-pressure adjustment mechanism in communication with the second cylinder, wherein the back-pressure adjustment mechanism is configured to adjust a volumetric flow rate of air exhausted from the second cylinder by the second piston during at least one of the first and second fastener driving cycles.
11 . A powered fastener driver comprising:
a first cylinder;
a first piston positioned within the first cylinder, the first piston being moveable between a top-dead-center position and at or near a bottom-dead-center position;
a second cylinder in fluid communication with the first cylinder;
a second piston positioned within the second cylinder, the second piston being moveable between a top-dead-center position and a bottom-dead-center position to initiate a fastener driving cycle;
a drive blade coupled to the second piston for movement therewith; and
a drive mechanism configured to drive the first piston between the top-dead-center position and at or near the bottom-dead-center position, the drive mechanism including a crank arm configured to rotate in a first direction to complete a first fastener driving cycle to drive a fastener into a workpiece and an opposite, second direction to complete a subsequent second fastener driving cycle to drive another fastener into the workpiece.
12 . The powered fastener driver of claim 11 , wherein the crank arm is configured rotate less than 360 degrees in both the first direction and the opposite, second direction.
13 . The powered fastener driver of claim 11 , wherein
the drive mechanism includes a cam coupled for co-rotation with the crank arm,
the cam includes a lobe configured to engage a latch when the crank arm reaches a predetermined angular position coinciding with the top-dead-center position of the first piston, and
the lobe moves the latch to an unlocked position so the second piston is able to move from the top-dead-center position to the bottom-dead-center position.
14 . The powered fastener driver of claim 13 , wherein the latch extends between the drive mechanism and the drive blade, wherein the latch is movable between a locked position, in which the latch engages the drive blade to secure the second piston in the top-dead-center position, and the unlocked position, in which the latch disengages the drive blade so the second piston is able to move from the top-dead-center position to the bottom-dead-center position.
15 . The powered fastener driver of claim 13 , wherein the lobe is formed as a protrusion on a first side of the cam and extends in an axial direction that is parallel with a rotational axis of the crank arm.
16 . The powered fastener driver of claim 11 , wherein the crank arm includes a stop surface configured to engage a fixed stop on a housing of the powered fastener driver prior to the first and second fastener driving cycles.
17 . A powered fastener driver comprising:
a first cylinder;
a first piston positioned within the first cylinder, the first piston being moveable between a top-dead-center position and at or near a bottom-dead-center position;
a second cylinder in fluid communication with the first cylinder;
a second piston positioned within the second cylinder, the second piston being moveable between a top-dead-center position and a bottom-dead-center position to initiate a fastener driving cycle;
a drive blade coupled to the second piston for movement therewith; and
a drive mechanism configured to drive the first piston between the top-dead-center position and at or near the bottom-dead-center position, the drive mechanism including a crank arm configured to rotate less than 360 degrees in alternating directions to complete consecutive fastener driving cycles to consecutively drive a fastener into a workpiece in each of the alternating directions.
18 . The powered fastener driver of claim 17 , wherein
the drive mechanism includes a cam coupled for co-rotation with the crank arm,
the cam includes a lobe configured to engage a latch when the crank arm reaches a predetermined angular position coinciding with the top-dead-center position of the first piston, and
the lobe moves the latch to an unlocked position so the second piston is able to move between the top-dead-center position to the bottom-dead-center position.
19 . The powered fastener driver of claim 18 , wherein
the crank arm includes an eccentric pin, and
a connecting rod pivotably couples to the eccentric pin to the first piston.
20 . The powered fastener driver of claim 19 , wherein the lobe extends in a direction parallel to the eccentric pin and is radially spaced from the eccentric pin.