Hydraulically powered impact device

Claim 2

The hydraulic device comprising: means forming a cylinder bore, a reciprocable member carrying a piston reciprocally disposed in the bore, and a valve member reciprocally disposed in the bore and adapted to sealingly engage the piston and divide the bore into first and second expansible fluid chambers such that when high pressure fluid is introduced to the first fluid chamber the combined fluid forces acting on the piston and the valve member will drive said reciprocable member against a load, said valve member being positioned between said first chamber and said piston and having a first surface exposed to the high pressure fluid of said first chamber and a second surface abutting the piston to transfer the fluid force on the first surface to the piston thereby supplementing the area of said piston to aid in moving said reciprocable member against the load, and means for separating the valve member from the piston after the load has been driven a distance to bypass fluid in the first expansible fluid chamber around the piston as the load returns the piston.

Claim 3

The hydraulic device of claim 1 wherein: the reciprocable member is an impact hammer, and further characterized by an energy storage device acting as the load to drive the hammer through a return stroke upon separation of the valve member from the piston.

Claim 4

The hydraulic device of claim 1 further characterized by: means for delaying the return of the piston by the load until the valve member has returned sufficiently to prevent the piston from catching the valve member.

Claim 5

The hydraulic device comprising: a reciprocable member carrying a piston dividing a cylinder bore into first and second cylinder chambers, and valve means reciprocable in said bore, said valve means adapted to statically engage said piston and seal said first chamber when said first chamber is pressurized permitting actuation of said piston in a second direction to drive a load, said valve means having a first surface area abutting said piston and including a second surface area in said first chamber for transmitting the pressure force in the first chamber to said piston by way of said abutting first surface area to supplement the pressure force against the piston to assist said piston in driving the load, and means associated with said valve means adapted to shift said valve means away from said piston in a first direction upon said piston reaching a predetermined position to cause rapid depressurization of said first chamber thereby permitting relatively unrestricted return of said piston by said load.

Claim 6

The hydraulic device comprising: a reciprocable member carrying a piston dividing a cylinder bore into first and second cylinder chambers, and valve means reciprocable in said bore, said valve means adapted to statically engage said piston and seal said first chamber when said first chamber is pressurized permitting actuation of said piston in a second direction to drive a load, said valve means having a first surface area abutting said piston and including a second surface area in said first chamber for transmitting the pressure force in the first chamber to said piston by way of said abutting first surface area to supplement the pressure force against the piston to assist said piston in driving the load, and means associated with said valve means adapted to shift said valve means away from said piston in a first direction upon said piston reaching a predetermined position to cause rapid depressurization of said first chamber thereby permitting relatively unrestricted return of said piston by said load.

Claim 7

A hydraulic device having a reciprocable member in a cylinder actuable against a load comprising: a first piston means mounted on said reciprocable member dividing the cylinder into opposite first and second cylinder chambers, said first piston means having a piston surface exposed to said first cylinder chamber for moving said reciprocable member against the load when said first chamber is pressurized, a second piston means having a first surface exposed to said first cylinder chamber and a second surface adapted to engage said first piston means when said first chamber is pressurized for transmitting the fluid force on said first surface to said first piston means, the pressure on said first surface thereby supplementing the pressure on said piston surface to assist in moving said reciprocable member against the load, and means associated with said second piston means adapted to cause said second piston means to shift away from said first piston means upon said first piston means reaching a predetermined position.

Claim 8

A hydraulic device having a reciprocable member in a cylinder actuable against a load comprising: a first piston means mounted on said reciprocable member dividing the cylinder into opposite first and second cylinder chambers, said first piston means having a piston surface exposed to said first cylinder chamber for moving said reciprocable member against the load when said first chamber is pressurized, a second piston means having a first surface exposed to said first cylinder chamber and a second surface adapted to engage said first piston means when said first chamber is pressurized for transmitting the fluid force on said first surface to said first piston means, the pressure on said first surface thereby supplementing the pressure on said piston surface to assist in moving said reciprocable member against the load, and means associated with said second piston means adapted to cause said second piston means to shift away from said first piston means upon said first piston means reaching a predetermined position.

Claim 9

The hydraulic comprising: a hydraulic cylinder having a fluid inlet and a fluid outlet, a piston carried on a rod reciprocable within said cylinder dividing said cylinder interior into first and second cylinder chambers, an auxiliary outlet port in said cylinder intermediate the inlet and outlet, valve means reciprocable in said cylinder having first and second opposite end surfaces, the second end surface having a greater effective area, said valve means adapted to statically engage said piston when said first chamber is pressurized to seal said first chamber, said first surface being exposed to said first chamber and supplementing the effective area of said piston to aid in moving said piston rod against a load, and means for admitting pressure fluid against said second end surface when said piston reaches a predetermined position thereby inducing a pressure differential across said valve to oppositely reciprocate said valve and place said first chamber in communication with said second chamber thereby allowing the load to return the piston relatively unimpeded.

Claim 10

The hydraulic comprising: a hydraulic cylinder having a fluid inlet and a fluid outlet, a piston carried on a rod reciprocable within said cylinder dividing said cylinder interior into first and second cylinder chambers, an auxiliary outlet port in said cylinder intermediate the inlet and outlet, valve means reciprocable in said cylinder having first and second opposite end surfaces, the second end surface having a greater effective area, said valve means adapted to statically engage said piston when said first chamber is pressurized to seal said first chamber, said first surface being exposed to said first chamber and supplementing the effective area of said piston to aid in moving said piston rod against a load, and means for admitting pressure fluid against said second end surface when said piston reaches a predetermined position thereby inducing a pressure differential across said valve to oppositely reciprocate said valve and place said first chamber in communication with said second chamber thereby allowing the load to return the piston relatively unimpeded.

Claim 11

A hydraulic device for applying impact forces to a body comprising: a housing defining a bore, an axially slidable hammer member in said housing bore defining with said bore an annular cylinder chamber having fluid inlet and outlet ports, energy storage means adapted to transmit energy to said hammer to deliver an impacting blow, piston means carried on said hammer in said bore defining first and second opposite expansible fluid chambers, said piston adapted to move said hammer to activate said energy storage device when said first cylinder is pressurized, valving means engagable with said piston and presenting a first surface area to pressure fluid in said first chamber to supplement the piston area and assist in moving said hammer against the energy storage means to a predetermined position by transferring to the energy storage means through the hammer the fluid forces on the valving means, and means for shifting said valving from said piston upon said hammer reaching said predetermined position to permit fluid to bypass the piston as energy from the energy storage device returns the piston.

Claim 12

A hydraulic device for applying impact forces to a body comprising: a housing defining a bore, an axially slidable hammer member in said housing bore defining with said bore an annular cylinder chamber having fluid inlet and outlet ports, energy storage means adapted to transmit energy to said hammer to deliver an impacting blow, piston means carried on said hammer in said bore defining first and second opposite expansible fluid chambers, said piston adapted to move said hammer to activate said energy storage device when said first cylinder is pressurized, valving means engagable with said piston and presenting a first surface area to pressure fluid in said first chamber to supplement the piston area and assist in moving said hammer against the energy storage means to a predetermined position by transferring to the energy storage means through the hammer the fluid forces on the valving means, and means for shifting said valving from said piston upon said hammer reaching said predetermined position to permit fluid to bypass the piston as energy from the energy storage device returns the piston.

Claim 13

The device of claim 7 wherein said energy storage means comprises an air spring device.

Claim 14

The device of claim 7 further including second valve means for bypassing fluid from said first chamber until at least a predetermined load is applied to said hammer member.

Claim 15

The device oF claim 9 wherein said hammer member is in abutting relationship with an anvil which abuts a tool member.

Claim 16

The device of claim 10 wherein said device is operatively mounted on a construction machine.

Claim 17

The device of claim 11 wherein said construction machine is a backhoe and said device is mounted on a boom member.

Claim 18

A hydraulic impact device for applying impact force to a body comprising: a housing defining a bore having a first section of smaller diameter than a second section, first and second bearing members closing the ends of said bore and carrying axially extending abutment members extending into said bore, a hammer member reciprocable in said bearing members and defining therewith and with said housing bore an annular cylinder chamber, energy storage means adapted to transmit energy to said hammer to deliver an impacting blow with the hammer, said energy storage means including compressible air spring means mounted adjacent said upper bearing and in contact with one end of said hammer whereby retraction of said hammer will compress said air spring to store energy therein, piston means carried on said hammer in said bore dividing said cylinder chamber into first and second cylinder chambers, said piston extending radially having an annular sealing surface adapted to form an annular seal with the upper bearing at the end of a retraction stroke, inlet port means communicating high pressure fluid with said first chamber, first outlet port means communicating with said second chamber through the upper bearing above the annular seal between the upper bearing and the piston, second outlet port means intermediate said inlet port and said first outlet port, valve means having a generally annular body with an exterior surface in slidable contact with said bore, said sleeve having a first end exposed to said first chamber and a second end adapted to statically engage said piston when said first chamber is pressurized to move said hammer in said second direction, the effective cross-sectional area of said second end being greater than the cross-sectional area of the first end as a result of the difference in diameters of the first and second sections of the bore, said valve means adapted to abut said upper bearing when said piston seals with said upper bearing to permit pressure fluid to be admitted against said second end of the valve to shift saif valve away from said piston and to uncover second outlet to depressurize said first chamber and release the piston from the upper bearing whereby the expansion of said air spring will accelerate said hammer, relatively unimpeded as the fluid bypasses the piston.

Claim 19

A hydraulic impact device for applying impact force to a body comprising: a housing defining a bore having a first section of smaller diameter than a second section, first and second bearing members closing the ends of said bore and carrying axially extending abutment members extending into said bore, a hammer member reciprocable in said bearing members and defining therewith and with said housing bore an annular cylinder chamber, energy storage means adapted to transmit energy to said hammer to deliver an impacting blow with the hammer, said energy storage means including compressible air spring means mounted adjacent said upper bearing and in contact with one end of said hammer whereby retraction of said hammer will compress said air spring to store energy therein, piston means carried on said hammer in said bore dividing said cylinder chamber into first and second cylinder chambers, said piston extending radially having an annular sealing surface adapted to form an annular seal with the upper bearing at the end of a retraction stroke, inlet port means communicating high pressure fluid with said first chamber, first outlet port means communicating with said second chamber through the upper bearing above the annular seal between the upper bearing and the piston, second outlet port means intermediate said inlet port and said first outlet port, valve means having a generally annular body with an exterior surface in slidable contact with said bore, said sleeve having a first end exposed to said first chamber and a second end adapted to statically engage said piston when said first chamber is pressurized to move said hammer in said second direction, the effective cross-sectional area of said second end being greater than the cross-sectional area of the first end as a result of the difference in diameters of the first and second sections of the bore, said valve means adapted to abut said upper bearing when said piston seals with said upper bearing to permit pressure fluid to be admitted against said second end of the valve to shift saif valve away from said piston and to uncover second outlet to depressurize said first chamber and release the piston from the upper bearing whereby the expansion of said air spring will accelerate said hammer, relatively unimpeded as the fluid bypasses the piston.

Claim 20

The device of claim 13 further including shuttle valve means having a first position bypassing fluid from said first chamber and a second flow blocking position, said shuttle valve being biased to said first position and adapted to be moved to said second position by a predetermined force being applied to move said hammer in a second direction.

Claim 21

The device of claim 14 wherein said hammer includes an axially slidable anvil member which is biased downwardly by the shuttle valve. 16.. A hydraulic impact device for applying impact forces to a body comprising: a housing defining a bore, an axially slidable hammer member in said housing bore defining with said bore an annular cylinder chamber having fluid inlet and outlet ports, energy storage means adapted to transmit energy to said hammer to deliver an impacting blow, piston means carried on said hammer in said bore defining first and second opposite expansible fluid chambers, said piston adapted to move said hammer to activate said energy storage device when said first cylinder chamber is pressurized, valving means engagable with said piston and presenting a first surface area to pressure fluid in said first chamber to supplement the piston area and assist in moving said hammer against the energy storage means to a pRedetermined position, and means for shifting said valving from said piston upon said hammer reaching said predetermined position to permit fluid to bypass the piston as energy from the energy storage device returns the piston, comprising means for admitting pressure fluid against a second valve surface having an area greater than said first surface whereby a pressure differential is imposed on said valve causing it to shift.

Claim 22

The hydraulic device comprising: a hydraulic cylinder having a fluid inlet and a fluid outlet, a piston carried on a rod reciprocable within said cylinder dividing said cylinder interior into first and second cylinder chambers, valve means reciprocable in said cylinder having first and second opposite end surfaces, the second end surface having a greater effective area, said valve means adapted to statically engage said piston when said first chamber is pressurized to seal said first chamber, said first surface being exposed to said first chamber and supplementing the effective area of said piston to aid in moving said piston rod against a load, and means for admitting pressure fluid against said second end surface when said piston reaches a predetermined position thereby inducing a pressure differential across said valve to oppositely reciprocate said valve and place said first chamber in communication with said second chamber thereby allowing the load to return the piston relatively unimpeded.

Claim 23

The hydraulic device comprising: a hydraulic cylinder having a fluid inlet and a fluid outlet, a piston carried on a rod reciprocable within said cylinder dividing said cylinder interior into first and second cylinder chambers, valve means reciprocable in said cylinder having first and second opposite end surfaces, the second end surface having a greater effective area, said valve means adapted to statically engage said piston when said first chamber is pressurized to seal said first chamber, said first surface being exposed to said first chamber and supplementing the effective area of said piston to aid in moving said piston rod against a load, and means for admitting pressure fluid against said second end surface when said piston reaches a predetermined position thereby inducing a pressure differential across said valve to oppositely reciprocate said valve and place said first chamber in communication with said second chamber thereby allowing the load to return the piston relatively unimpeded.