# US 2025/0367802 A1 · Gas spring-powered fastener driver with pressure mechanism > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0367802 A1 - Document ID: US20250367802A1 - Status: Published application - Kind: A1 - Application number: 19/296,275 - Filed: 2025-08-11 - Published: 2025-12-04 - Earliest claimed: 2021-07-16 - Assignees: Milwaukee Electric Tool Corporation - Applicants: Milwaukee Electric Tool Corporation - Inventors: David A. Bierdeman; Troy C. Thorson; Jacob N. Zimmerman; Andrew R. Wyler; Travis W. Leathrum; David C. Graf; Alex J. Brasel - Web page: https://patentgrep.com/patent/US20250367802A1 ## CPC - B25C 1/008: {Safety devices} - B25C 1/047: {Mechanical details} - B25C 1/06: operated by electric power - B25C: HAND-HELD NAILING OR STAPLING TOOLS; MANUALLY OPERATED PORTABLE STAPLING TOOLS (for shoemaking A43D) ## Abstract A gas spring-powered fastener driver includes a cylinder, a storage chamber cylinder having pressurized air in communication with the cylinder, a moveable piston positioned within the cylinder, a driver blade extending from a first side of the piston and movable therewith between a top-dead-center position and a bottom-dead-center position, a one-way seal carried onboard the piston and disposed between the piston and the cylinder, the one-way seal being configured permit a bypass flow of pressurized air from the first side of the piston, past the one-way seal, and into a space within the cylinder adjacent an opposite, second side of the piston during movement of the piston and driver blade from the top-dead-center position to the bottom-dead-center position, thereby increasing a pressure of the pressurized air within the cylinder and storage chamber cylinder, and a pressure relief valve in fluid communication with the storage chamber cylinder. ## Claims ### Claim 1 A gas spring-powered fastener driver comprising: a cylinder; a storage chamber cylinder having pressurized gas in communication with the cylinder; a moveable piston positioned within the cylinder; a driver blade extending from a first side of the piston and movable therewith between a top-dead-center position and a bottom-dead-center position, the driver blade defining a driving axis; a lifter operable to move the driver blade from the bottom-dead-center position toward the top-dead-center position, the lifter is configured to engage the driver blade when moving the driver blade from the bottom-dead-center position toward the top-dead-center position; a one-way seal carried onboard the piston and disposed between the piston and the cylinder, the one-way seal being configured permit a bypass flow of the pressurized gas from the first side of the piston, past the one-way seal, and into a space within the cylinder adjacent an opposite, second side of the piston during movement of the piston and driver blade from the top-dead-center position to the bottom-dead-center position, thereby increasing a pressure of the pressurized gas within the cylinder and storage chamber cylinder; and a pressure relief valve in fluid communication with the storage chamber cylinder and configured to open in response to the pressure of the pressurized gas within the storage chamber cylinder exceeding a predetermined value. ### Claim 2 (depends on 1) The gas spring-powered fastener driver of claim 1, wherein the one-way seal is configured to prevent the pressurized gas from passing through an annular space between the piston and the cylinder. ### Claim 3 (depends on 2) The gas spring-powered fastener driver of claim 2, wherein the one-way seal allows the pressurized gas to pass through the annular space in a first direction and prevents the pressurized gas from travelling through the annular space in an opposite, second direction. ### Claim 4 (depends on 3) The gas spring-powered fastener driver of claim 3, wherein the bypass flow passes through the annular space when the driver blade reaches the bottom-dead-center position. ### Claim 5 (depends on 1) The gas spring-powered fastener driver of claim 1, wherein the pressure relief valve includes: a seat positioned within a passageway in the storage chamber cylinder fluidly communicating an interior of the storage chamber cylinder with ambient surroundings of the fastener driver, a pin disposed in the passageway, and a spring positioned between the seat and the pin to bias the pin toward the storage chamber cylinder to seal the passageway. ### Claim 6 (depends on 5) The gas spring-powered fastener driver of claim 5, wherein when the pressure of the pressurized gas within the storage chamber cylinder exceeds the predetermined value, the pin is moved away from the storage chamber cylinder, against the bias of the spring, to open the passageway. ### Claim 7 (depends on 1) The gas spring-powered fastener driver of claim 1, further comprising a bumper positioned beneath the piston in a vertical direction to absorb impact energy from the piston, and wherein as the piston approaches the bottom-dead-center position, the piston compresses the bumper causing the pressure on the first side of the piston to exceed the pressure on the second side of the piston. ### Claim 8 (depends on 1) The gas spring-powered fastener driver of claim 1, wherein the one-way seal is configured permit the bypass flow of the pressurized gas from the first side of the piston, past the one-way seal, and into a space within the cylinder adjacent an opposite, second side of the piston due to a greater pressure on the first side of the piston than the first side of the second side of the piston. ### Claim 9 (depends on 1) The gas spring-powered fastener driver of claim 1, wherein a decrease in differential pressure between the first side and the second side causes the one-way seal to permit the bypass flow of the pressurized gas from the first side of the piston, past the one-way seal. ### Claim 10 (depends on 1) The gas spring-powered fastener driver of claim 1, wherein the one-way seal includes an arm that is movable away from the cylinder to permit the bypass flow of the pressurized gas from the first side of the piston, past the one-way seal, and into a space within the cylinder adjacent an opposite, second side of the piston. ### Claim 11 (depends on 10) The gas spring-powered fastener driver of claim 10, wherein the arm has a contact surface that slides along a wall of the cylinder to prevent the pressurized gas from travelling from the first second side of the piston to the first side of the piston. ### Claim 12 A gas spring-powered fastener driver comprising: a cylinder; a storage chamber cylinder having pressurized gas in communication with the cylinder; a moveable piston positioned within the cylinder, the piston including a first side and second side opposite the first side, the second side being exposed to the pressurized gas in the cylinder and storage chamber cylinder; a driver blade attached to the piston and movable therewith between a top-dead-center position and a bottom-dead-center position, the driver blade defining a driving axis; a lifter operable to move the driver blade from the bottom-dead-center position toward the top-dead-center position, the lifter is configured to engage the driver blade when moving the driver blade from the bottom-dead-center position toward the top-dead-center position; and a sliding seal disposed between the piston and the cylinder; wherein during movement of the piston and driver blade from the top-dead-center position to the bottom-dead-center position, a pressure on the second side of the piston is greater than a pressure on the first side of the piston and the sliding seal is configured to prevent the pressurized gas from passing through an annular space between the piston and the cylinder, and wherein as the piston approaches the bottom-dead-center position and the pressure on the first side of the piston exceeds the pressure on the second side of the piston, the sliding seal is configured to permit a bypass flow of the pressurized gas to pass in a direction from the first side of the piston through the annular space between the piston and the cylinder into a space within the cylinder adjacent the second side of the piston, thereby increasing a pressure of the pressurized gas within the cylinder and storage chamber cylinder. ### Claim 13 (depends on 12) The gas spring-powered fastener driver of claim 12, further comprising a bumper positioned beneath the piston in a vertical direction to absorb impact energy from the piston, and wherein as the piston approaches the bottom-dead-center position, the piston compresses the bumper causing the pressure on the first side of the piston to exceed the pressure on the second side of the piston. ### Claim 14 (depends on 12) The gas spring-powered fastener driver of claim 12, wherein a decrease in differential pressure between the first side and the second side causes the sliding seal to permit the bypass flow of the pressurized gas from the first side of the piston through the annular space into the space within the cylinder adjacent to the second side of the piston. ### Claim 15 (depends on 12) The gas spring-powered fastener driver of claim 12, further comprising a pressure relief valve in fluid communication with the storage chamber cylinder and configured to open in response to the pressure of the pressurized gas within the storage chamber cylinder exceeding a predetermined value. ### Claim 16 (depends on 15) The gas spring-powered fastener driver of claim 15, wherein the pressure relief valve includes: a seat positioned within a passageway in the storage chamber cylinder fluidly communicating an interior of the storage chamber cylinder with ambient surroundings of the fastener driver, a pin disposed in the passageway, and a spring positioned between the seat and the pin to bias the pin toward the storage chamber cylinder to seal the passageway. ### Claim 17 (depends on 16) The gas spring-powered fastener driver of claim 16, wherein when the pressure of the pressurized gas within the storage chamber cylinder exceeds the predetermined value, the pin is moved away from the storage chamber cylinder, against the bias of the spring, to open the passageway. ### Claim 18 (depends on 12) The gas spring-powered fastener driver of claim 12, wherein the sliding seal includes an arm that is movable to away from the cylinder to permit the bypass flow of the pressurized gas to pass in the direction from the first side of the piston through the annular space between the piston and the cylinder into the space within the cylinder adjacent the second side of the piston. ### Claim 19 (depends on 18) The gas spring-powered fastener driver of claim 18, wherein the arm has a contact surface that slides along a wall of the cylinder to prevent the pressurized gas from travelling through the annular space from the first second side of the piston to the first side of the piston. ### Claim 20 (depends on 12) The gas spring-powered fastener driver of claim 12, wherein the sliding seal is positioned within a groove in the piston and includes a contact surface that is movable relative to the cylinder to engage and disengage an inner wall thereof.