US3925985A — Impact actuator

Claim 1

Independent Claim 149 words

In an actuator capable of delivering repeated impacts to a variable, stopped position comprising the combination of an impact member movable back and forth relative to said position, an expansible drive for driving said member toward said position while expanding, and a return for returning said impact member and recompressing said drive, said return including a follower which follows said impact member to its variable stopped position and a hydraulic system enabled by said position of said follower to apply return force to said impact member, the improvement wherein said hydraulic system includes a hydraulic drive for said follower in the following direction, a valve separate from said follower and impact member effective to direct said flow alternately to drive said follower in following direction and drive said impact member in its return direction and a control for actuating said follower drive upon said driving of said impact member.

Claim 2

Dependent Claim 149 words

In an actuator capable of delivering repeated impacts to a variable, stopped position comprising the combination of an impact member movable back and forth relative to said position, an expansible drive for driving said member toward said position while expanding, and a return for returning said impact member and recompressing said drive, said return including a follower which follows said impact member to its variable stopped position and a hydraulic system enabled by said position of said follower to apply return force to said impact member, the improvement wherein said hydraulic system includes a hydraulic drive for said follower in the following direction, a valve separate from said follower and impact member effective to direct said flow alternately to drive said follower in following direction and drive said impact member in its return direction and a control for actuating said follower drive upon said driving of said impact member.

Claim 3

Dependent Claim 47 words

The actuator of claim 1 wherein said hydraulic system includes a source of hydraulic fluid which comprises a positive displacement constant flow pump and said impact member has a constant cross-section at its opposite end regions whereby movement of said impact member does not displace hydraulic fluid.

Claim 4

Dependent Claim 51 words

The actuator of claim 1 including a trigger, said follower being returnable by said hydraulic fluid with said impact member, and said trigger being effective both to release said impact member to be driven by said expansible drive and to actuate said control for separate following motion of said follower drive.

Claim 5

Dependent Claim 53 words

The actuator of claim 3 wherein said trigger comprises a vent opened by said impact member and follower reaching said return position, said vent operable both to relieve the net hydraulic return pressure upon said impact member to the point where it is overcome by said expansible drive and to actuate said control.

Claim 6

Dependent Claim 64 words

The actuator of claim 4 wherein said valve is held in a first position by pressure returning said impact member, the valve effective to admit return fluid to said impact member and to vent said follower drive, and said vent effective, through relief of return pressure, to operate said valve to a second position to apply hydraulic pressure to and control said follower drive.

Claim 7

Dependent Claim 21 words

The actuator of claim 5 wherein said vent is also effective to open a further vent of said impact member return.

Claim 8

Dependent Claim 52 words

The actuator of claim 5 wherein said valve is operative in said second position to apply the pressure of said follower drive to said valve upon build-up of pressure in said follower drive associated with said follower reaching said impact member, said pressure operative to reverse said valve to said first position.

Claim 9

Dependent Claim 64 words

The actuator of claim 4 wherein said trigger is formed by mating portions of said follower and impact member providing a seal when seated and creating pressure conditions whereby said impact member and follower are returned as a unit, and in the return position said vent operative to break said seal and expose a surface of said impact member to forces concelling return forces.

Claim 10

Dependent Claim 83 words

The actuator of claim 8 wherein said follower and said impact member when seated together define a fluid volume, said fluid volume vented through a passage in said follower to a low pressure region, said follower having a surface portion exposed to hydraulic pressure effective to press said follower and impact member together and prevent relief through said passage of pressure acting upon said impact member, and said vent operative to introduce hydraulic pressure to said fluid volume tending to break said seal.

Claim 11

Dependent Claim 19 words

The actuator of claim 1 wherein said follower telescopes upon said impact member in response to said follower drive.

Claim 12

Dependent Claim 64 words

The actuator of claim 10 in the form of a linear actuator wherein said impact member comprises a reciprocable piston having an enlarged middle portion, said follower compRises a sleeve linearly telescopically fitted about the exterior of said piston, having a flared end engageable upon said enlarged middle portion of said piston and having an oppositely directed surface exposed to said hydraulic follower drive.

Claim 13

Dependent Claim 132 words

The actuator of claim 11 including a housing forming a first chamber into which said piston and flared end of said sleeve extend, a first hydraulic line connected thereto for said hydraulic return, a second chamber to which said oppositely directed surface of said follower is exposed, a second hydraulic line connected thereto for said follower drive, a third chamber intermediate said first and second chambers and normally sealed therefrom, a third hydraulic line connected thereto for venting, a passage extending from said third chamber to the space between said flared end of said sleeve and said enlarged portion of said piston, and a vent passage in the exterior of said sleeve positioned so that when the sleeve is in its return position, said first chamber is vented to said third chamber.

Claim 14

Dependent Claim 34 words

The actuator of claim 12 including a positive displacement, constant flow hydraulic pump and a valve effective alternately to direct flow to said second line and exhaust from said first line and vice versa.

Claim 15

Dependent Claim 59 words

The actuator of claim 13 wherein a branch from the outlet of said pump is connected so that pressure therefrom urges said valve toward a first position directing said flow to said first line and exhaust from said second line, said valve constructed so that relief of said pressure on said branch line causes said flows to be reversed.

Claim 16

Dependent Claim 79 words

The actuator of claim 1 in the form of a linear actuator wherein said impact member comprises a linear piston, a stationary tube in which the inner end of said piston is fitted, the inner end of said piston and the interior of said tube cooperating to form a volume for an expansible gas drive and said follower comprising a sleeve slidably engaged upon the exterior of said tube and forming therewith a hydraulic chamber for said follower drive.

Claim 17

Dependent Claim 83 words

The actuator of claim 1 in the form of a linear actuator wherein said impact member comprises a linear piston, said follower comprising a sleeve slidably engaged upon the exterior of said piston, said housing and a portion of the side of said piston forming a hydraulic chamber for said follower drive, said piston extending beyond said chamber in sealed relation into a further chamber, the end of said piston disposed in said further chamber and exposed therein to an expansible fluid drive.

Claim 18

Dependent Claim 81 words

The actuator of claim 1 in the form of a linear actuator wherein said impact member comprises a linear piston including a housing defining a bottoming position for said impact member in the absence of a workpiece at the impactreceiving position, said follower and housing cooperatively constructed to vent said follower drive prior to said follower reaching said impact member in said bottoming position, thereby preventing said follower from reaching the position for enabling application of return forces to said piston.

Claim 19

Dependent Claim 61 words

The actuator of claim 16 wherein said further chamber is connected to a supply of makeup fluid through a check valve that permits inflow but not outflow to said further chamber, and a vent line from said further chamber that is exposed when said impact member travels beyond a position predetermined to limit the maximum fluid trapped in said further chamber.

Claim 20

Dependent Claim 160 words

An actuator capable of delivering repeated impacts to a variable position comprising the combination of an impact member movable back and forth relative to said position, an expansible fluid drive for driving said member toward said position while expanding, and a return for returning said impact member and recompressing said drive, said drive consisting of a volume of fluid connected through a check valve to a supply of makeup fluid to allow inflow to said volume of fluid but not outflow from said volume of fluid, and a vent from said volume of fluid opened by Said impact member upon overtravel beyond a predetermined position and closed by said impact member upon return travel back to said predetermined position said vent thereby being adapted to vent excess fluid at low pressure before it is recompressed by return motion of said impact member whereby said vent is effective to limit the maximum quantity of fluid trapped as said volume of fluid.

Claim 21

Dependent Claim 160 words

An actuator capable of delivering repeated impacts to a variable position comprising the combination of an impact member movable back and forth relative to said position, an expansible fluid drive for driving said member toward said position while expanding, and a return for returning said impact member and recompressing said drive, said drive consisting of a volume of fluid connected through a check valve to a supply of makeup fluid to allow inflow to said volume of fluid but not outflow from said volume of fluid, and a vent from said volume of fluid opened by Said impact member upon overtravel beyond a predetermined position and closed by said impact member upon return travel back to said predetermined position said vent thereby being adapted to vent excess fluid at low pressure before it is recompressed by return motion of said impact member whereby said vent is effective to limit the maximum quantity of fluid trapped as said volume of fluid.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-12-15	1979-06-16	1979-12-16	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-12-15	1983-06-16	1983-12-16	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-12-15	1987-06-16	1987-12-16	$7700.00	Window Closed / Lapsed

Impact actuator

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