Piston seal for powered fastener driver
A powered fastener driver includes a housing, a cylinder supported by the housing, and a moveable piston positioned within and moveable along a driving axis of the cylinder. The piston includes a circumferential groove on an outer peripheral surface thereof. A driver blade is attached to the piston and moveable therewith between a top-dead-center (TDC) position and a driven or bottom-dead-center (BDC) position. A seal assembly is received in the circumferential groove. The seal assembly is configured to create a seal between the piston and the cylinder. The seal assembly includes a biasing member and a seal member positioned radially outwardly of the biasing member relative to the driving axis.
1 . A powered fastener driver comprising:
a housing;
a cylinder supported by the housing;
a piston positioned within and moveable along a driving axis of the cylinder, the piston including a circumferential groove on an outer peripheral surface thereof;
a driver blade attached to the piston and moveable therewith between a top-dead-center (TDC) position and a bottom-dead-center (BDC) position;
a seal assembly received in the circumferential groove and configured to create a seal between the piston and the cylinder, the seal assembly including a biasing member and a seal member positioned radially outward of the biasing member relative to the driving axis;
a lifter operable to move the driver blade from the BDC position toward the TDC position; and
a transmission for providing torque to the lifter.
2 . The powered fastener driver of claim 1 , wherein the seal member has a trapezoidal cross-sectional shape.
3 . The powered fastener driver of claim 1 , wherein the seal member has a cross-sectional shape that is tapered in a radially outward direction.
4 . The powered fastener driver of claim 1 , wherein the biasing member is made from an elastomeric material, and wherein the seal member is made from a plastic material.
5 . The powered fastener driver of claim 4 , wherein the biasing member is an O-ring.
6 . The powered fastener driver of claim 1 , wherein the biasing member is configured to pre-load the seal member against the cylinder.
7 . The powered fastener driver of claim 1 , wherein the circumferential groove includes a uniform width, the width being measured parallel to the driving axis.
8 . The powered fastener driver of claim 1 , wherein a width of the biasing member is equal to or greater than a width of the seal member, the width of each of the biasing member and the seal member being measured parallel to the driving axis.
9 . A driving mechanism for a powered fastener driver, the driving mechanism comprising:
a cylinder supported by the powered fastener driver;
a storage chamber in fluid communication with the cylinder;
a piston moveable within the cylinder between a top-dead-center (TDC) position and a bottom-dead-center (BDC) position, the piston including a circumferential groove on an outer surface thereof;
a seal assembly received within the circumferential groove, the seal assembly including a biasing member and an annular seal member positioned radially outward of the biasing member relative to a driving axis of the cylinder, wherein the seal member is configured to slidably engage the cylinder;
a lifter operable to move the piston from the BDC position toward the TDC position; and
a transmission for providing torque to the lifter.
10 . The driving mechanism of claim 9 , wherein the piston includes a second circumferential groove positioned on the outer surface of the piston, and wherein a guide ring is received within the second circumferential groove to guide the piston within the cylinder.
11 . The driving mechanism of claim 10 , wherein the guide ring is formed from polyoxymethylene (POM) or polytetrafluoroethylene (PTFE).
12 . The driving mechanism of claim 11 , wherein the annular seal member is formed from a material that is different from a material of the guide ring.
13 . The driving mechanism of claim 9 , wherein the biasing member is disposed between the piston and the seal member, and wherein the biasing member applies a pre-load force to the seal member in a direction towards the cylinder.
14 . The driving mechanism of claim 9 , wherein the biasing member is an elastomeric ring.
15 . A powered fastener driver comprising:
a housing;
a cylinder supported by the housing;
a piston positioned within and moveable along a driving axis of the cylinder, the piston including a first circumferential groove on an outer peripheral surface of the piston and a second circumferential groove on the outer peripheral surface of the piston;
a driver blade attached to the piston and moveable therewith between a top-dead-center (TDC) position and a bottom-dead-center (BDC) position;
a guide ring disposed within the second circumferential groove, the guide ring configured to guide motion of the piston within the cylinder;
a seal assembly received in the first circumferential groove and configured to create a seal between the piston and the cylinder, the seal assembly including a biasing member and a seal member positioned radially outwardly of the biasing member relative to the driving axis;
a lifter operable to move the driver blade from the BDC position toward the TDC position; and
a transmission for providing torque to the lifter.
16 . The powered fastener driver of claim 15 , wherein the guide ring inhibits contact between the outer peripheral surface of the piston and the cylinder.
17 . The powered fastener driver of claim 16 , wherein the seal member slidably engages the cylinder.
18 . The powered fastener driver of claim 15 , wherein the seal member has a trapezoidal cross-sectional shape that is tapered in a radially outward direction.
19 . The powered fastener driver of claim 15 , further comprising a third circumferential groove on the outer peripheral surface of the piston, and a second guide ring disposed within the third circumferential groove.
20 . The powered fastener driver of claim 19 , wherein the first circumferential groove is disposed between the second circumferential groove and the third circumferential groove.