. Upon removal of the magnetic field from coil 130, rod 140, armature 134, and piston 122 move away from the actuator 104 by spring 144 back to their neutral positions obstructing fluid from the actuator cavity 146c to accumulator reservoir 150. Check valve 120b then closes blocking fluid from exiting actuator cavity 146c. It should be appreciated the embodiments include embedded magnet actuator 116 being replaced by any type of bi-directional electrical actuator that is operable to compress or activate two piston pumps independently as described herein. Embodiments of bi-directional electrical actuator include voice coil actuators, moving magnet actuators, and one or more motors operable actuate lateral movement of a rod that can independently compress or activate two piston pumps or via a cam to independently compress or activate the two piston pumps.

Accumulator 112 is fluidly connected to single acting cylinder 104 within cylinder body 102 through a series of passageways 146 which can include a plurality of check valves 120, a pump and control valve. Embodiments of accumulator 112, passageways 146, single acting cylinder 104, and embedded magnet actuator 116 allow fluid (e.g., oil) to communicate or flow to accumulator 112 from single acting cylinder 104 and to single acting cylinder 104 from accumulator 112 in response to movement of armature 134 and the magnetic flux created by current passing through coil 130 when activated with a first and second polarity direction.

Cylinder body 102 includes a fill port 106, which is fluidly connected to passageways 146. Fill port 106 provides an opening into passageways 146 such that fluid and/or oil can be provided into passageways 146. Fill port 106 is fluidly connected to passageway 146a which is fluidly connected to check valve 120a. Check valve 120a is fluidly connected to pump reservoir 150. Check valve 120a is operable to allow the flow of fluid from passageway 146a to pump reservoir 150 and passageways 146 throughout the assembly 100 until the fluid pressure from the side of the fill port 106 reaches a predetermined threshold. Upon removal of fluid pressure at the fill port 106, the check valve 120a will prevent fluid to pass from cylinder passages 146 and pump reservoir 150 into passageway 146a. Pump reservoir 150 is fluidly connected to check valve 120c.

Check valve 120c is fluidly connected to pump reservoir 150 and passageway 146b (shown in FIG. 3). Check valve 120c is operable to prevent the flow of fluid from pump reservoir 150 to passageway 146b until the fluid pressure from the pump reservoir 150 reaches a predetermined threshold, which is created by lowering the pressure in cavity 146b when the pump 126 is activated by compressing spring 142 with the embedded magnet actuator rod 140 causing a high differential pressure across check valve 120c. Passageway 146b is fluidly connected to check valve 120d. Check valve 120d is fluidly connected to passageway 146c, check valve 120b, and drain valve 118. Passageway 146c is fluidly connected to relief valve 154, which is fluidly connected to pump reservoir 150.

Passageways 146b and 146c each include a bleed screw 108. Bleed Screws 108 are operable to allow a temporary opening between passageways 146b, 146c and the surrounding environment such that air can be removed from passageways 146b, 146c.

Drain valve 118 and check valve 120b is adjacent one distal end of rod 140. Piston 126 with check valve 120c is adjacent to the distal end of rod 140 that is opposite the drain valve 118. It should be appreciated that embodiments of drain valve 118 include an electrically operated solenoid drain valve in which current can be passed through a coil in the solenoid causing an armature in the solenoid to move and either open or close the drain valve. Embodiments provide that movement of armature 134 and rod 140 in response to current passing through coil 130 activated in a first polarity direction will cause rod 140 to come into contact with piston 126 causing piston 126 with check valve 120c to move in the longitudinal direction towards accumulator 112 until armature 134 hits the pole stop 188 (shown in FIG. 21). During this movement, fluid will be allowed to flow from pump reservoir 150 to passageway 146b between check valve 120c and 120d. The amount of fluid from the reservoir that is allowed to flow will be equivalent to the increase in volume created during the movement of piston 126. The check valve 120c will close when the volume of fluid displaced is equal to the volume of movement of piston 126. When current is removed from coil 130, the piston 126, rod 140, and armature 134 will be pushed back towards their neutral positions by spring 142 until piston 126 stops on retainer 182 (shown in FIG. 21), which provides a lip or physical stop for piston 126. The motion of the armature 134 when current is removed from coil 130 creates fluid pressure that opens check valve 120d and opens a connection into actuator cavity 146c. The amount of fluid moved is equal to the amount of fluid displaced by piston 126 and check valve 120c when the armature 134 moves away from the accumulator along the longitudinal axis 110 until the piston 126 contacts the retainer 182 and movement is stopped. The pressure from the fluid will then act upon single acting cylinder 104 and will cause single acting cylinder 104 to move in the longitudinal direction against spring 160. The amount of movement of single acting cylinder 104 is based on the amount of fluid displaced per cycle of pump piston 126 and closed check valve 120c during the deactivation cycle of coil 130.

Embodiments provide that movement of armature 134 and rod 140 in response to current passing through coil 130 in a second polarity direction will cause rod 140 to come into contact with check valve 120b and drain valve 118 and will cause check valve 120b and drain valve 118 to move in the longitudinal direction to the open position. In the open position, fluid built up from accumulator 112 acting against single acting cylinder 104 will be allowed to flow through drain valve 118 from passageway 146c through passageway 146f toward accumulator reservoir 150. Relief valve 154 is fluidly connected to passageway 146c and pump reservoir 150. Relief valve 154 is operable to allow a flow of fluid from passageway 146c to pump reservoir 150 when the pressure from the fluid within passageway 146c reaches a predetermined threshold at which point relief valve 154 will allow a flow of fluid until the pressure within passageway 146c reaches a certain threshold.

Embodiments of device 100 further include an optional position sensor 160 (shown in FIG. 4). Position sensor 160 is operably connected to single acting cylinder 104 and is able to sense a relative location of single acting cylinder 104 in the longitudinal direction. As depicted in FIG. 4, embedded magnet actuator 116 is operated by a controller 162 that is operable to cause a current to pass through coil 130, which will cause armature 134 to move in the longitudinal direction. Embodiments of controller 162 include an electronic controller with an H-bridge that can be built into the controller or can be a separate and remote from the controller. As shown in FIG. 4, the current that passes through coil 130 will cause the polarity of the coil 130 to change to and from −/+ (causing the armature 134 with rod 140 to move in the longitudinal direction toward the accumulator 112) to +/− (causing the armature 134 with rod 140 to move in the longitudinal direction toward the drain valve 118). It should be noted that the polarity that is applied to coil 130 to cause directional motion of armature 134 is dependent on the orientation of the magnets 132 with respect to one another as installed in core tube 138 as well as the direction of the winding of coil 130. Device 100 also includes vents or ports that are operable to move between an open position and a closed position and are fluidly connected to passageways 146 to allow air to be removed from passageways 146.

Reference is now made to FIG. 5, which illustrates a perspective view of device 100. In FIG. 5, the exterior wall of device 100 is transparent such that the interior elements of device 100 are visible. Also shown in FIG. 5 is position sensor 160, which is operably coupled to device 100. In one embodiment, device 100 has a diameter of 2.75 inches, a flange diameter of 3.25 inches and a length of 7.08 inches. It should be appreciated that embodiments of device 100 include any size provided it operates as set forth herein.

Illustrated in FIG. 6 is an exemplary flow path of fluid that passes through passageways 146 when embedded magnet actuator 116 is caused move towards pump A and accumulator 112. In this embodiment, the arrows within passageways 146 illustrate that fluid will drain from accumulator 112 and move through pump A toward to passageway 146 toward cylinder 104 and cavity A. In should be appreciated that in the embodiments depicted in FIGS. 5-6, 9-11, and 13-20, cylinder 104 is a is a double acting cylinder (as opposed to the single acting cylinder 104 as shown in FIGS. 2-3). Embodiments of the double acting cylinder and the single acting cylinder include double acting actuators and single acting actuators, respectively. It should be appreciated that embodiments of the double acting cylinder and the single acting cylinder are not limited to cylinders, but include vanes and actuators that are not cylinders. Here, cylinder 104 includes a cavity A and a cavity B that are each operable to maintain a fluid and have such fluid moved into and out of such cavity. It should also be appreciated that due to the arrangement of rod 140 with respect to the pump pistons 168, 126 and check valves 120c, 172 disposed in pumps A and B as depicted in FIGS. 5-7, 9-15, and 21-25, the embedded magnet actuator 116 is operable to charge the pump pistons 168, 126 with fluid when it compresses the pistons away from the neutral position while their respective springs are operable to pump fluid through the system upon return to their neutral or centered position. FIG. 7 illustrates a close-up view of pump A. Pump A is adjacent to rod 140 and rod pin 164. Pump A piston assembly 166 that includes a spring loaded check valve having a pump piston 168, ball holder 170, a ball 172, a first spring 174 and a second spring 176. Ball 172 is maintained within port 178 of pump piston 168 by first spring 174 obstructing a flow of fluid therethrough. The location of pump piston 168 is maintained by spring 176. When rod 140 with rod pin 164 moves towards pump piston 168, second spring 176 is compressed and the fluid is allowed to flow. In one embodiment, pump A piston assembly 166 can be replaced with a shuttle valve pump piston assembly 178 (shown in FIG. 8a) or pump piston assembly 178 having a reed valve 180 (shown in FIG. 8b). Rod pin 164 slidably disposed within body 500 (shown in FIG. 7) and isolates the fluid within core tube 138 from fluid within pump A by preventing fluid from passing between the interior of the core tube 138 and pump A. It should be appreciated that the portion of rod 140 adjacent pump B does not include a rod pin. As such, fluid is able to flow between the core tube 138 and pump B.

Reference is now made to FIGS. 9-15, which illustrate an exemplary device 100 having two drain valves 152a, 152b. In this embodiment, cavity A of double acting cylinder 104 is fluidly connected to drain valve 152a via passageway 146d. Similarly, cavity B is fluidly connected to drain valve 152b via passageway 146e. Drain valves 152a, 152b are operable to allow a flow of fluid from cavities A and B to accumulator reservoir 150. FIG. 10 illustrates a cross-sectional view of device 100 having two drain valves 152a, 152b illustrating passageway 146f from pump B to cavity B. In this embodiment, passageway 146f includes a check valve 120e. FIG. 11 illustrates a cross-sectional view of device 100 having two drain valves 152a, 152b with passageways 146g from accumulator 112 to an inlet of pump B. Referring to FIG. 12, shown is device 100 having two drain valves 152a, 152b illustrating passageway 146h from cavity B to drain valve 152a. Here, a pilot piston will open the drain valve 152a to drain cavity A of double acting actuator from passage 146d to the accumulator reservoir 150 in response to the fluid pressure in cavity B.

Reference is now made to FIG. 13, which illustrates an exemplary block diagram of device 100. It should be appreciated that the lines connecting the block elements illustrated in the block diagrams depicted herein represent the passageways that allow fluid to flow therebetween and therefore fluidly connect such block elements. In this embodiment, device 100 is operable to charge the single coil embedded magnet solenoid and move an armature either towards pump A or pump B to allow a flow of fluid toward the other pump that has not been compressed. In this embodiment, device 100 includes relief valve A and relief valve B. Relief valve B is fluidly connected to the accumulator and the inlet of Pump B and can drain fluid from cavity B of the double acting cylinder. Relief valve A is fluidly connected to the accumulator and the inlet of pump A and can drain fluid from cavity A of the double acting cylinder. Device 100 shown in FIG. 14 operates similarly that shown in FIG. 13, however, there are no relief valves in this embodiment. In the embodiment shown in FIGS. 4, 13-15, and 22-25 each pump limits the maximum pressure by using the spring for the pumping. The mechanical limitations of the spring limit the output pressure capability of the pump. FIG. 15 illustrates another exemplary device 100. In this embodiment, pumps A and B include shuttle valves 1502, 1504 rather than a spring loaded check valve.

Referring to FIGS. 16-20, shown are exemplary steps in which the embedded magnet actuator 116 will cause fluid to flow through device 100. The arrows in the passageways in FIGS. 16-20 illustrate the direction of flow of fluid through the paths. It should be appreciated that in the embodiments depicted in FIGS. 15-20 and 26-27, the embedded magnet actuator 116 is operable to pump fluid through the system by compressing the pistons 1602, 1604 (movement away from neutral) while the springs 1603, 1605 within the pistons 1602, 1604 will cause the pistons 1602, 1604 to charge with the fluid when the rod 1606 and armature 1608 from the embedded magnet actuator 116 return to their neutral or centered position. In FIG. 16, the spring 1603, 1605 within the piston 1602, 1604 causes the piston 1602, 1604 to return opening check valve 1610 and charge the pump with fluid or oil. At this point, the check valve 1610 in pump 1604 opens and check valve 1612 will be closed obstructing the flow of fluid to the double acting actuator. When the coil 130 is energized with a first polarity, the embedded magnet actuator 116 pushes the piston of pump 1604 towards the accumulator 112 causing check valve 1610 in pump 1604 to close and check valve 1612 to open which allows the volume of fluid being pumped to flow through check valve 1612 and into the double acting actuator cavity A. The force applied by embedded magnet actuator 116 minus the spring load divided by the pump piston area is the pressure applied to the double acting actuator piston. In FIG. 17, embedded magnet actuator 116 pumps fluid through the system and compresses the springs. Embedded magnet actuator 116 is operable to compress pump B when the coil is operated with a second polarity to allow a flow of fluid through a passageway in communication to double acting actuator cavity B, inlet of drain valve B, and pilot piston of drain valve A (not shown). Also shown is the fluid communication from the accumulator reservoir to inlets of pump A and pump B. The pilot pressure from pump A shown, acts on the piston and opens drain valve B to allow cavity B to drain when pump A is operating and pump B is not. Also shown is the fluid bleed from cavity B to the environment.

In FIG. 18, the embedded magnet actuator 116 is operable to compress pump A to allow a flow of fluid to cavity A. Relief valve A is operable to allow a flow to accumulator 112 if the pressure from the fluid reaches a certain threshold. In FIG. 19, embedded magnet actuator 116 compresses pump B and applies pressure to the pilot piston of drain valve A. This allows a flow of fluid from cavity A to flow through the passageways from double acting actuator cavity A to drain valve A and to the accumulator reservoir fluidly connected at the inlet of pump A. Referring to FIG. 20, shown is an exemplary device 100 having check valves 2002, 2004 intermediate pump A, pump B and relief valve A and B, respectively.

Referring to FIG. 22, shown is a block diagram of an alternative embodiment of device 100. In the embodiment shown in FIG. 22, device 100 includes drain valve A which is fluidly connected to the passageway flowing from the embedded magnet solenoid to check valve 3, and drain valve B which is fluidly connected to the passageway flowing from the embedded magnet solenoid to check valve 2. This arrangement allows the double acting cylinder to remain in a static position when the embedded magnet solenoid is powered off. Also shown in FIG. 22 are two controlled leaks. Each controlled leak is located past the pilot pistons of drain valve A and B and are fluidly connected to the accumulator reservoir. Embodiments provide that the controlled leaks can allow a flow of fluid at a plurality of different rates. FIG. 22 also depicts two optional check valves. Optional check valves are located in series with the pilot pistons of drain valves A and B, respectively. It should be noted that the optional check valve can be deployed within or integral with the drain valves A and B rather than as a separate element. Referring to FIG. 23, shown is another block diagram of an embodiment of device 100. In this embodiment, device 100 includes a safety drain valve 2300. This arrangement also allows the cylinder to remain static when the embedded magnet solenoid is powered off. The safety drain valve 2300 allows for the fluid to be drained from cavity A if the system loses power allowing the cylinder to move towards cavity A that the oil is being drained from. It should be appreciated that the location of the safety drain valve 2300 with respect to the other elements of device 100 is determined by the fail safe direction required of the double acting cylinder. Embodiments provide that the safety drain valve 2300 can be disposed such that it is operable to drain fluid from cavity B instead of cavity A as depicted in FIG. 23 allowing the cylinder to move towards cavity B that the oil is being drained from. FIG. 23 also illustrates two controlled leaks. In this embodiment, controlled leaks are located past the pilot pistons of drain valves A and B, respectively, and are located in parallel to safety drain valve 2300. Also, shown in FIG. 23 are optional check valves disposed in series with the pilot piston of drain valves A and B, respectively. It should be appreciated that the optional check valve and controlled leaks can be disposed within or integral to Drain Valves A and B, and that the controlled leaks can be located within the pilot piston of drain valves A and B. Reference is now made to FIG. 24, which depicts yet another block diagram of an embodiment of device 100. In this embodiment, the relief valves have been removed from device 100, which limits the maximum fluid pressure in the system. As depicted, pump A and pump B are arranged such that movement of the armature of the embedded magnet solenoid toward either pump A or pump B compresses the spring within their respective pistons. After the pump pistons are compressed and the armature moves back to its center or neutral position, the springs cause the pump pistons to move back to their neutral position thereby pumping fluid through the passageways. Since the springs are causing or forcing the fluid to flow, the upper limits of the force the springs are able to generate act as a cap or maximum for the amount of pressure that can be generated within the device 100. In FIG. 24, controlled leaks at shown as being located past the pilot piston to the accumulator reservoir. Controlled leaks are disposed in series with optional check valves, which are positioned such that they are in parallel with drain valve pilot piston A and B. It should be appreciated that the controlled leaks can be disposed with the pilot piston of drain valves A and B.

Referring now to FIG. 25, depicted is another block diagram of yet a further alternative embodiment of device 100. This embodiment is similar to that found in FIG. 24, however, in this embodiment, device 100 includes a safety drain valve 2300 in addition to having drain valves A and B. It should be appreciated again that the location of the safety drain valve 2300 is determined by the fail safe direction required of the double acting cylinder towards the cylinder the oil is being drained from by the safety drain valve. Embodiments of the safety drain valve 2300 include it being located within device 100 such that it is operable to drain fluid from cavity B instead of cavity A as depicted in FIG. 25. Similar to FIG. 24, FIG. 25 includes controlled leaks being located past the pilot piston to the accumulator reservoir in parallel with optional check valves. Optional check valves illustrated in FIG. 24 are located in parallel to drain valve pilot piston A and B, respectively. It should be noted that the optional check valve and the controlled leaks can be deployed within drain valves A and B. The controlled leaks can be disposed within the pilot piston of drain valves A and B. Referring to FIG. 26, shown is another block diagram of another embodiment of device 100. In this embodiment, device 100 includes check valves 2 and 5. Check valve 2 is disposed between pump B and cavity B of the cylinder and its outlet is connected to relief valve B inlet and cylinder cavity B. Check valve 5 is disposed between pump A and cavity A of the cylinder and its outlet is connected to relief valve A inlet and cylinder cavity A. As indicated by the dotted line in FIG. 26, Drain valve A pilot section is connected between check valves 1 and 2. As indicated by the dotted line in FIG. 26, Drain valve B pilot section is connected between check valves 4 and 5. FIG. 26 also illustrates controlled leaks located past the pilot piston to the accumulator reservoir. In this embodiment, controlled leaks are disposed in series with optional check valves. Optional check valves are disposed in series with the pilot piston of drain valves A and B, respectively. It should be noted that the controlled leak and optional check valves can be located within the drain valves A and B. The controlled leaks can be deployed within pilot pistons A and B. FIG. 27 presents a block diagram of device 100 similar to that found in FIG. 26. However, in this embodiment, there is a safety drain valve 2300 disposed in parallel with the drain valve A. It should be appreciated that the location of safety drain valve 2300 is determined by the fail safe direction required of the double acting cylinder. Embodiments provide that the safety drain valve 2300 can be located such that it is operable to drain fluid from cavity B when connected in parallel to drain valve B. As shown, drain valve A pilot is fluidly connected between check valves 1 and 2, and drain valve B pilot is connected between check valves 4 and 5. FIG. 27 illustrates controlled leaks located past the pilot piston to accumulator reservoir and are in series with optional check valves. Optional check valves are disposed in series with the pilot piston of drain valves A and B. It should be appreciated that the controlled leaks can be disposed within the drain valve pilot piston. It should also be noted that the optional check valve can be located within drain valves A and B. One of the controlled leaks is located in parallel with safety drain valve 2300. It should be appreciated that in each of the embodiments of device 100 illustrated in FIGS. 22-27, the double acting cylinder is operable to remain in a static position when the embedded magnet solenoid is powered off.

It should be appreciated that FIGS. 28-30 show additional embodiments of device 100 in which pilot operated logic control valves that control the motion of the embedded magnet actuator when it receives a pressure signal from the solenoid pumping system as previously described herein to the control valves as described and shown herein. FIG. 27 illustrates an embodiment of device 100 that utilizes two three-way pilot operated valves, which are typically in the closed position. FIG. 29 shows an embodiment that utilizes two three-way pilot operated valves that are typically in the open position. FIG. 30 shows one 3-position, 5-ported, spring centered pilot operated valve.

Reference is now made to FIGS. 31 and 32, which depict block diagrams of exemplary electro-hydrostatic actuator assembly 3100 having a first accumulator 3108 and a second accumulator 3110. Shown in FIGS. 31 and 32 are electro-hydrostatic actuator assembly 3100 having a cylinder body 3102 (shown in FIG. 33). Cylinder body 3102 includes a single acting cylinder 3104 (shown in FIG. 31) and a fill port 3106. Alternatively, cylinder body 3102 includes a double acting cylinder 3204 (shown in FIG. 32). Electro-hydrostatic actuator assembly 3100 also includes a first accumulator 3108, a second accumulator 3110, a first piston pump 3112, a second piston pump 3114, an embedded magnet actuator 3116, a pressure isolation pin 3118, a first check valve 3120, a second check valve 3122, a release valve 3124, a 3-way pilot operated valve 3126 and an air bleed valve 3128. Embodiments include orifices 3130, 3132. It should be appreciated that single acting cylinder 3104 includes a position sensor 3105 operable to sense a position of the location of the single acting cylinder 3104.

Embedded magnet actuator 3116 is similar to that embedded magnet actuator 3116 described above. However, in this embodiment, embedded magnet actuator 3116 is operable to activate first piston pump 3112 and second piston pump 3114. In this embodiment, passing current through its coil 3134 of embedding magnet actuator 3116 in a first polarity direction will cause armature 3136 to move toward the first piston pump 3112 in a first direction. This will cause the first check valve within first piston pump 3112 to open and allow a flow of fluid through it. Movement of armature 3136 toward first piston pump 3112 in the first direction will also cause pressure isolation pin 3118 to compress first pump spring 3138 and will draw or urge fluid from the first accumulator 3108.

When current through coil 3134 stops, armature 3136 will return to a centered or neutral position within embedded magnet actuator 3116 such that it is not acting on either first piston pump 3112 or second piston pump 3114. When armature 3136 is moving toward the neutral position the first pump spring 3138 of the first piston pump 3112 will push or move the first piston pump 3112 in a second direction opposite the first direction towards the second piston pump 3114, and the first check valve 3120 will open allowing a flow of fluid. Movement of the first piston pump 3112 by moving the first pump spring 3138 from the compressed state to an uncompressed state will urge or move fluid in the first piston pump 3112 through the second check valve 3120 into the second accumulator 3110. After the volume of fluid from the first piston pump 3112 has moved to the second accumulator 3110, check valve 3120 will close preventing a flow of fluid.

The second accumulator 3110 is fluidly connected to the second piston pump 3114 via an inlet of the second piston pump 3114 by one of a plurality of passageways within the cylinder body 3102. When current is passed through its coil 3134 of embedded magnet actuator 3116 in a second polarity direction will cause armature 3136 to move toward the second piston pump 3114 in a second direction. The second polarity is opposite the first polarity. The movement of the armature 3136 in the second direction is opposite the first direction. Movement of the armature 3136 to move toward the second piston pump 3114 in a second direction will cause the third check valve 3140 to open and allow a flow of fluid through it. Movement of armature 3136 toward second piston pump 3114 in the second direction will also cause the rod of embedded magnet actuator 3116 to compress second pump spring 3142. This will cause second piston pump 3114 to draw or urge fluid from the second accumulator 3110 via the fluidly connected passageway. When the current ceases to pass through coil 3134 of embedded magnet actuator 3116, armature 3136 will move to the neutral position. The neutral position pertains to a location along the long axis of the embedded magnet actuator 3116 in which armature 3136 is centered and the rod is not compressing both the first piston pump 3112 and second piston pump 3114. The second pump spring 3142 will then move from a compressed state to an uncompressed state, the third check valve 3140 will close. Next, a fourth check valve 3144 will open and allow pressurized flow of fluid into the single acting cylinder 3104. The flow of fluid into the single acting cylinder 3104 each time the second pump spring 3142 is moved from a compressed state to an uncompressed state will correspond to the volume of fluid maintained by the second piston pump 3114 when the second pump spring 3142 is in the compressed state. Accordingly, fluid will stop flowing into the single acting cylinder 3104 when the second pump spring 3142 is in the uncompressed state.

It should be appreciated that embodiments include the fluid pressure created by the first piston pump 3114 when fluid is moved by the first piston pump 3114 from the first accumulator 3108 to the second accumulator 3108 will be at a first level. The fluid pressure created by the second piston pump 3114 when fluid is moved by the second piston pump 3114 from the second accumulator 3108 to the single acting cylinder 3104 will be at a second level. Embodiments include the second level being greater than the first level. In this regard embodiments of the electro-hydrostatic actuator assembly 3100 are operable to create higher levels of fluid pressure than an assembly having only a single accumulator.

Referring to FIGS. 32-35, shown is an alternative embodiment of an electro-hydrostatic actuator assembly 3200 having a cylinder body 3202. Electro-hydrostatic actuator assembly 3200 includes a first accumulator 3208, a second accumulator 3210, a first piston pump 3212, a second piston pump 3214, an embedded magnet actuator 3216, a pressure isolation pin 3218, a first check valve 3220, a second check valve 3222, a third check valve 3223, a release valve 3224, first air bleed valve 3228, and a second air bleed valve 3229. In this embodiment, movement of armature 3236 towards the first piston pump 3212 causes first piston pump 3212 to move fluid from the first piston pump 3212 to the second accumulator 3210 and check valve 3222 to open. The fluid will then move to cavity A 3223 of double acting cylinder 3204. When armature 3236 moves back to a neutral position, first piston pump 3212 is urged by first pump spring 3238 to return to an uncompressed state, which moves fluid into first piston pump 3212 from the first accumulator 3208. When the armature 3236 moves towards the second piston pump 3214, the pressure isolation pin causes the second piston pump 3214 to move fluid from the second accumulator 3210 to cavity B 3225 of the double acting hydraulic cylinder 3204. When the armature 3236 moves back to the neutral position, second piston pump 3214 is urged by second pump spring 3242 to the uncompressed state, which moves fluid into second piston pump 3214 from the second accumulator 3210.

Referring to FIGS. 36-41, shown are exemplary embodiments of a flexible reed valve 4300. An embodiment of reed valve 4300 is also illustrated as reed valve 180 in FIG. 8b. Embodiments of flexible reed valve 4300 can be utilized in hydraulic actuators depicted herein, and any type of fluid pumps or fluid pump systems. Embodiments of flexible reed valve 4300 can be used in place of check valves in multiple locations in hydraulic systems and pneumatic systems. Embodiments of a flexible reed valve 4300 include an inlet that allows fluid to flow into the flexible reed valve 4300, and an outlet that allows fluid to flow out of the flexible reed valve 4300. Embodiments of flexible reed valve 4300 are operable to obstruct and prevent the movement or flow of a fluid through a fluid pump or fluid pump system until a threshold pressure (also known as a cracking pressure) is reached on the inlet side of the flexible reed valve 4300. Once the threshold pressure differential (or cracking pressure) is reached between the inlet side and the outlet side of the flexible reed valve 4300, the flexible reed valve 4300 flexes or bends allowing the fluid on the inlet to flow through the flexible reed valve 4300 and out the outlet of the flexible reed valve