Fastener driving tool

Claim 2

A pneumatically operated fastener driving tool comprising a housing having a cavity defining a fluid reservoir, a cylinder in said housing, a piston slidably mounted in said cylinder, a cylinder valve means for controlling the admission of fluid and for the exhaustion of fluid from one end of said cylinder, a piston return reservoir in said housing, air passage means connecting said piston return reservoir and said cylinder and including port means opening in sAid cylinder adjacent the other end thereof, said piston including a pair of spaced peripheral grooves in its outer wall, a ring sealing member in the one of said grooves toward said one end of said cylinder effecting a pneumatic seal between said piston and said cylinder, air passage means in said piston extending from the other of said grooves around said one of said grooves and including means defining ports in said other of said grooves, a resilient ring sealing member in said other of said grooves normally seated against said ports and expandable upon a selected pressure differential between said one end of said cylinder and said other end thereof to unseat from said ports to provide for fluid to bypass around the first sealing member from said one end of said cylinder to said other end thereof providing for passage of air into said piston return reservoir.

Claim 3

A fastener driving tool as set forth in claim 1 wherein said last mentioned sealing member is an O-ring.

Claim 4

A fastener driving tool as set forth in claim 2 wherein the inside diameter of said O-ring in its unstressed state is less than the minimum diameter of said other of said grooves, and the diametrical thickness of said O-ring is less than the width of said other of said grooves.

Claim 5

A fastener driving tool as set forth in claim 1 wherein said piston is generally cup-shaped with a central cavity opening toward said one end of said cylinder and said air passage means comprises a plurality of passageways communicating between the inner surface of said other of said grooves and said cavity.

Claim 6

A fastener driving tool as set forth in claim 1 and including a resilient annular bumper adjacent said other end of said cylinder engageable by said piston and defining a pneumatic seal when said piston is at said other end of said cylinder.

Claim 7

A fastener driving tool as set forth in claim 1 wherein said cylinder is provided with an enlarged diameter portion at its upper end defining a shoulder, and wherein said ring sealing member sets above said shoulder when said piston is in its normal position to retain the piston in said normal position.

Claim 8

A pneumatically operated fastener driving tool comprising a housing having a cavity defining a fluid reservoir, a cylinder in said housing having an open upper end and an enlarged diameter portion forming a shoulder with the remainder of said cylinder and extending from said shoulder to the open upper end of the cylinder, a piston slidably mounted in said cylinder and provided with at least one peripheral groove in its outer wall, a ring sealing member in said groove effecting a pneumatic seal between said piston and said cylinder and setting above said shoulder when said piston is in its normal position thereby holding said piston in said normal position, a cylinder valve means for controlling the admission of fluid and the exhaustion of fluid from the open upper end of said cylinder, said cylinder valve means including structure engaging the piston to stop the piston in said normal position, the shoulder in the cylinder being spaced downwardly from the open upper end thereof a distance such that the ring sealing member rests on the shoulder when the piston engages the structure on the cylinder valve means, and means controlling operation of said cylinder valve.

Claim 9

A pneumatically operated fastener driving tool comprising a housing having a cavity defining a fluid reservoir, a cylinder in said housing having an open upper end and an enlarged diameter portion forming a shoulder with the remainder of said cylinder and extending from said shoulder to the open upper end of the cylinder, a piston slidably mounted in said cylinder and provided with at least one peripheral groove in its outer wall, a ring sealing member in said groove effecting a pneumatic seal between said piston and said cylinder and setting above said shoulder when said piston is in its normal position thereby holding said piston in said normal position, a cylinder valve means for controlling the admission of fluid and the exhaustion of fluid from the open upper end of said cylinder, said cylinder valve means including structure engaging the piston to stop the piston in said normal position, the shoulder in the cylinder being spaced downwardly from the open upper end thereof a distance such that the ring sealing member rests on the shoulder when the piston engages the structure on the cylinder valve means, and means controlling operation of said cylinder valve.

Claim 10

In combination: a. a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir in open and continuous communication with the cylinder below the piston throughout its travel between said Retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting port through the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir below the piston when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 11

In combination: a. a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir in open and continuous communication with the cylinder below the piston throughout its travel between said Retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting port through the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir below the piston when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 12

In combination: a. a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir in open and continuous communication with the cylinder below the piston throughout its travel between said retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting check valve means through the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir below the piston when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 13

In combination: a. a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir in open and continuous communication with the cylinder below the piston throughout its travel between said retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting check valve means through the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir below the piston when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 14

In combination: a. a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir in open and continuous communication with the cylinder below the piston throughout its travel between said retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a port through the piston and communicating with the fluid under pressure advancing the piston, a valve seat surrounding the piston and carrying a constricted check valve element to yieldingly open the port into the cylinder below the piston and into said reservoir when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakAge guideway.

Claim 15

In combination: a. a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir in open and continuous communication with the cylinder below the piston throughout its travel between said retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a port through the piston and communicating with the fluid under pressure advancing the piston, a valve seat surrounding the piston and carrying a constricted check valve element to yieldingly open the port into the cylinder below the piston and into said reservoir when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakAge guideway.

Claim 16

In combination: a a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a substantially close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a snubber means comprising a body of resilient material surrounding the driver and with a seat having sealed engagement with the bottom of the piston upon arrestment of the piston at said actuated position; e. a closed fluid reservoir in open and continuous communication with the cylinder above said snubber seat and below the piston throughout its travel between said retracted and actuated positions; f. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting port through and opening above the bottom of the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir when the first mentioned means is operated to charge the cylinder; g. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 17

In combination: a a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a substantially close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a snubber means comprising a body of resilient material surrounding the driver and with a seat having sealed engagement with the bottom of the piston upon arrestment of the piston at said actuated position; e. a closed fluid reservoir in open and continuous communication with the cylinder above said snubber seat and below the piston throughout its travel between said retracted and actuated positions; f. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting port through and opening above the bottom of the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir when the first mentioned means is operated to charge the cylinder; g. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 18

In combination: a. a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a substantially close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a snubber means comprising a body of resilient material surrounding the driver and with a seat having sealed engagement with the bottom of the piston upon arrestment of the piston at said actuated position; e. a closed fluid reservoir in open and continuous communication with the cylinder above said snubber seat and below the piston throughout its travel between said retracted and actuated positions; f. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting check valve through and opening above the bottom of the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir when the first mentioned means is operated to charge the cylinder; g. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 19

In combination: a. a single stroke fluid pressure operated motor having a cylinder with a piston operable therein between a retracted position at one end of the cylinder and an actuated position at the other and closed end of the cylinder, and with a driver extended from the piston and through a substantially close fitting limited leakage guideway at the said other closed end of the cylinder; b. means operable to charge and to exhaust the cylinder at said one end thereof; c. restraining means normally holding the piston at rest at said retracted position; d. a snubber means comprising a body of resilient material surrounding the driver and with a seat having sealed engagement with the bottom of the piston upon arrestment of the piston at said actuated position; e. a closed fluid reservoir in open and continuous communication with the cylinder above said snubber seat and below the piston throughout its travel between said retracted and actuated positions; f. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting check valve through and opening above the bottom of the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir when the first mentioned means is operated to charge the cylinder; g. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 20

In combination: a. a single stroke fluid pressure operated motor having a cylinder chamber with an open ended cylinder seated therein to reciprocably receive a piston operable between a retracted position at said open end of the cylinder and an actuated position at the other seated and closed end of the cylinder, and with a driver extended from the piston and out of the seAted closed end of the cylinder and through a closed fitting limited leakage guideway in said cylinder chamber; b. means operable to charge and to exhaust the cylinder at said open end thereof, from fluid pressure stored in said cylinder chamber; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir surrounding the cylinder and in continuous communication with the cylinder through an opening therein below the piston throughout its travel between said retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting port through the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir below the piston when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 21

In combination: a. a single stroke fluid pressure operated motor having a cylinder chamber with an open ended cylinder seated therein to reciprocably receive a piston operable between a retracted position at said open end of the cylinder and an actuated position at the other seated and closed end of the cylinder, and with a driver extended from the piston and out of the seAted closed end of the cylinder and through a closed fitting limited leakage guideway in said cylinder chamber; b. means operable to charge and to exhaust the cylinder at said open end thereof, from fluid pressure stored in said cylinder chamber; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir surrounding the cylinder and in continuous communication with the cylinder through an opening therein below the piston throughout its travel between said retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting port through the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir below the piston when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 22

In combination: a. a single stroke fluid pressure operated motor having a cylinder chamber with an open ended cylinder seated therein to reciprocably receive a piston operable between a retracted position at said open end of the cylinder and an actuated position at the other seated and closed end of the cylinder, and with a driver extended from the piston and out of the seated and closed end of the cylinder and through a close fitting limited leakage guideway in said cylinder chamber; b. means operable to charge and to exhaust the cylinder at said open end thereof, from fluid pressure stored in said cylinder chamber; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir surrounding the cylinder and in continuous communication with the cylinder through an opening therein below the piston throughout its travel between said retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting check valve means through the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir below the piston when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the build-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 23

In combination: a. a single stroke fluid pressure operated motor having a cylinder chamber with an open ended cylinder seated therein to reciprocably receive a piston operable between a retracted position at said open end of the cylinder and an actuated position at the other seated and closed end of the cylinder, and with a driver extended from the piston and out of the seated and closed end of the cylinder and through a close fitting limited leakage guideway in said cylinder chamber; b. means operable to charge and to exhaust the cylinder at said open end thereof, from fluid pressure stored in said cylinder chamber; c. restraining means normally holding the piston at rest at said retracted position; d. a closed fluid reservoir surrounding the cylinder and in continuous communication with the cylinder through an opening therein below the piston throughout its travel between said retracted and actuated positions; e. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting check valve means through the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir below the piston when the first mentioned means is operated to charge the cylinder; f. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the build-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 24

In combination: a. a single stroke fluid pressure operated motor having a cylinder chamber with an open ended and externally flanged cylinder seated therein to reciprocably receive a piston operable between a retracted position at said open and flanged end of the cylinder and an actuated position at the other seated and closed end of the cylinder, and with a driver extended from the piston and out of the seated end of the cylinder and through a substantially close fitting limited leakage guideway in said cylinder chamber; b. means operable to charge and to exhaust the cylinder at said open and flanged end thereof, from fluid pressure stored in said cylinder chamber; c. restraining means normally holding the piston at rest at said retracted position; d. a snubber means comprising a body of resilient material surrounding the driver and with a seat having sealed engagement With the bottom of the piston during its arrestment at the actuated position; e. a closed fluid reservoir defined by the seated end and flanged end of the cylinder engaging the cylinder chamber and in open and continuous communication with the cylinder through an opening therein above said snubber seat and below the piston throughout its travel between said retracted and actuated positions; f. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting port through and opening above the bottom of the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir when the first mentioned means is operated to charge the cylinder; g. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.

Claim 25

In combination: a. a single stroke fluid pressure operated motor having a cylinder chamber with an open ended and externally flanged cylinder seated therein to reciprocably receive a piston operable between a retracted position at said open and flanged end of the cylinder and an actuated position at the other seated and closed end of the cylinder, and with a driver extended from the piston and out of the seated end of the cylinder and through a substantially close fitting limited leakage guideway in said cylinder chamber; b. means operable to charge and to exhaust the cylinder at said open and flanged end thereof, from fluid pressure stored in said cylinder chamber; c. restraining means normally holding the piston at rest at said retracted position; d. a snubber means comprising a body of resilient material surrounding the driver and with a seat having sealed engagement With the bottom of the piston during its arrestment at the actuated position; e. a closed fluid reservoir defined by the seated end and flanged end of the cylinder engaging the cylinder chamber and in open and continuous communication with the cylinder through an opening therein above said snubber seat and below the piston throughout its travel between said retracted and actuated positions; f. and air return means for movement of the piston from said actuated position to said retracted position when the first mentioned means is operated to exhaust the cylinder and comprising, a fluid restricting port through and opening above the bottom of the piston and communicating with the fluid under pressure advancing the piston and open into said reservoir when the first mentioned means is operated to charge the cylinder; g. whereby there is a build-up of fluid pressure in the reservoir as the piston reaches the said actuated position, and whereby the built-up fluid pressure is applied to the piston and returns the same to the retracted position when the first mentioned means is operated to exhaust the cylinder followed by exhaust of said built-up pressure through said limited leakage guideway.