PNEUMATIC EXCAVATOR AND METHODS OF USE

A pneumatic excavator is configured to be pneumatically actuated using a safety mechanism, and includes a primary actuator; a secondary actuator fluidly coupled to the primary actuator; a flow valve fluidly coupled to the primary actuator; a shuttle valve fluidly coupled to the primary actuator, the secondary actuator and the flow valve; and a barrel coupled to an egress of the flow valve, the barrel defining an outlet of the pneumatic excavator. Actuating the primary and secondary actuators causes compressed air to be transmitted from the secondary actuator to the primary actuator and then to the flow valve to open the flow valve such that the compressed air exits through the outlet. Actuating one actuator and not the other causes the compressed air to be transmitted to the exit port of the shuttle valve and then to the flow valve to close the flow valve and prevent air flow therethrough.

TECHNICAL FIELD

Implementations are directed to excavators, and more particularly to hand-held pneumatic excavators and methods of use.

BACKGROUND

Compressed air excavators cause compressed air to exit from a nozzle disposed at an end of an open pipe, which may be useful in operations such as loosening soil from buried pipes, gas mains, cables and cleaning. In prior approaches, pressurized water directed at the soil resulted in the generation of hazardous waste by the water mixing with contaminants in the soil that requires special treatment prior to disposal. In other approaches, mechanical digging implements such as blades and picks having hard cutting edges often damage the objects to be excavated or cleaned. The use of compressed air has the advantage of avoiding generation of hazardous waste while loosening soil without causing damage to the object targeted.

SUMMARY

A pneumatic excavator configured to be pneumatically actuated is thus provided. According to implementations, a pneumatic excavator includes a primary actuator; a secondary actuator fluidly coupled to the primary actuator; a shuttle valve may include a first inlet port fluidly coupled to a delivery port of the primary actuator, a second inlet port fluidly coupled to a delivery port of the secondary actuator; a flow valve may include a first port fluidly coupled to the primary actuator by at least one air actuation conduit and a second port fluidly coupled to an exit port of the shuttle valve; a barrel coupled to an egress of the flow valve, where an egress of the barrel defines an outlet of the pneumatic excavator. A primary flow passage may be defined at least by the flow valve and the barrel. Actuating the primary actuator and the secondary actuator causes compressed air to be transmitted from the secondary actuator to the primary actuator and through the at least one air actuation conduit to the first port of the flow valve to cause the flow valve to move to an open position such that the compressed air from the supply of compressed air passes through the primary flow passage and exits through the outlet of the pneumatic excavator. Then, when actuating one of the primary actuator or the secondary actuator and not actuating the other, causes the compressed air to be transmitted to the exit port of the shuttle valve fluidly coupled to the second port of the flow valve to cause the flow valve to move to a closed position, where in the closed position, the flow valve prevents the compressed air from the supply of compressed air from passing therethrough.

In various implementations and alternatives, a constant pressure conduit may be included, where a first end of the constant pressure conduit may be coupled to the pneumatic excavator at an upstream position from an egress of the flow valve, and a second end of the constant pressure conduit may be coupled to the secondary actuator.

In such implementations and alternatives, an air conduit may be provided that fluidly couples the primary actuator to the secondary actuator, where when the secondary actuator is actuated, the air conduit may be fluidly coupled to the constant pressure conduit. In addition or alternatively, the primary actuator further includes a primary actuator valve, and as the secondary actuator is actuated and when the primary actuator is actuated, the primary actuator valve may be configured to fluidly couple the constant pressure conduit to the first port of the flow valve. In addition or alternatively, as the secondary actuator is actuated and the primary actuator is not actuated, the delivery port of the primary actuator fluidly couples the air conduit to the first inlet port of the shuttle valve.

In implementations alternatives including the constant pressure conduit, the secondary actuator may further include a secondary actuator valve, where when the primary actuator is actuated and the secondary actuator is not actuated, the delivery port of the secondary actuator valve may be configured to fluidly couple the constant pressure conduit to the second inlet port of the shuttle valve.

In various implementations and alternatives, when neither the primary actuator nor the secondary actuator are actuated, the secondary actuator may be configured to transmit the compressed air via the delivery port to the second inlet port of the shuttle valve such that the flow valve is retained in the closed position or caused to move to the closed position, where in the closed position, the flow valve prevents the compressed air from the supply of compressed air from passing therethrough.

In various implementations and alternatives, at least one of the primary actuator or the secondary actuator may include a spool valve having a spool biased by a biasing mechanism. In such implementations and alternatives, the biasing mechanism may include a return spring.

In various implementations and alternatives, in the closed position of the flow valve, a piston of the flow valve may seal against a valve seat.

In various implementations and alternatives, at least one vent port may be included and configured to vent compressed air from the flow valve. In such implementations and alternatives, at least one vent port may be defined in the primary actuator or the secondary actuator.

In various implementations and alternatives, the flow valve may be free of a biasing mechanism such that the flow valve requires the compressed air to move the flow valve to the open position and to the closed position.

According to other implementations, a method of pneumatically actuating a pneumatic excavator may involve supplying compressed air to a pneumatic excavator from a compressed air supply, the pneumatic excavator may include an elongated barrel, a primary actuator, a secondary actuator, and a flow valve, the elongated barrel having an ingress and an egress, said ingress configured to be fluidly connected to the supply of compressed air, said egress defining an outlet of the pneumatic excavator, the primary actuator may include at least one air actuation conduit and the primary actuator configured to be fluidly coupled to a shuttle valve, the secondary actuator fluidly coupled to the primary actuator and to the shuttle valve, the flow valve fluidly coupled to the primary actuator and to the shuttle valve, where a primary flow passage is defined at least by the flow valve and the barrel. The primary actuator and the secondary actuator may be actuated to cause compressed air to be transmitted from the secondary actuator to the primary actuator to the flow valve to cause the flow valve to move to an open position such that the compressed air from the supply of compressed air passes through the primary flow passage and exits through the outlet of the pneumatic excavator. Then one of the primary actuator or the secondary actuator may be actuated while the other is not actuated, causing the compressed air to be transmitted to the shuttle valve to the flow valve to cause the flow valve to move to a closed position such that the compressed air from the supply of compressed air may be prevented from passing through the flow valve.

In various implementations and alternatives, during the supplying of compressed air, compressed air may be constantly delivered to a constant pressure conduit fluidly coupled to an intake port of the secondary actuator. In such implementations and alternatives, the actuating of one and not the other, involves actuating the secondary actuator and not the primary actuator, and where the air actuation conduit further includes a first air actuation conduit fluidly coupling the primary actuator and the secondary actuator such that the compressed air may be constantly delivered to the air actuation conduit and to the primary actuator.

In addition or alternatively, the air actuation conduit may further include a first air actuation conduit and a second air actuation conduit, and during the actuating of the primary actuator and the secondary actuator, the first air actuation conduit may fluidly couple the primary actuator and the secondary actuator such that the compressed air may be constantly delivered to the first air actuation conduit and to the primary actuator, and the second air actuation conduit fluidly couples the primary actuator and the flow valve such that the compressed air may be constantly delivered from the primary actuator to the flow valve. In addition or alternatively, actuating one actuator and not the other includes actuating the primary actuator and not the secondary actuator, and the secondary actuator further includes an air conduit fluidly coupling a delivery port of the secondary actuator and the shuttle valve such that the compressed air may be constantly delivered to the shuttle valve via the air conduit.

In various implementations and alternatives, during actuation of one of the primary actuator or the secondary actuator and not the other, the shuttle valve may allow air to enter an entry port from the actuated actuator and prevents air from entering the shuttle valve from the other unactuated actuator.

In various implementations and alternatives, the flow valve may be free of a biasing mechanism such that the flow valve requires the compressed air to move the flow valve to the open position and to the closed position.

DETAILED DESCRIPTION

Turning to the Figures,FIG.1illustrates a pneumatic air excavator100of the present disclosure in an exemplary soil excavating operation. A proximal end110of the pneumatic air excavator100is removably coupled to an air supply via an elongated delivery line111. The air supply may be compressed or pressurized air, which may be provided by an air compressor such as an air compressor truck. The air supply may be air (e.g., a mixture of oxygen and nitrogen), a gas or a mixture. A distal end120of the pneumatic air excavator100may include an extension122and a nozzle130(see, e.g.,FIG.2A) configured to deliver the compressed air, for instance, to break apart soil covering a buried target object, e.g., a pipe, cable, or other structure(s). A barrel140extending between the proximal and distal end110,120of the pneumatic air excavator100may be held by a user P during use. The barrel140may include an actuator assembly150movably coupled to an exterior141of the barrel140by a releasable coupling160(see, e.g.,FIG.2A). The actuator assembly150may be held by one hand of the user P for controlling an on/off status of the pneumatic air excavator100, while a different region of the pneumatic air excavator100may be held by the other hand of the user P, such as at a safety mechanism165proximate a primary valve or flow valve170. As the soil is loosened during operation of the pneumatic air excavator100, an industrial vacuum V may extract the loosened soil and may for instance deposit the soil in a location for future use or removal.

FIGS.2A and2Billustrate an isometric view and an exploded isometric view, respectively, of the pneumatic air excavator100of the present disclosure. As shown inFIG.2A, components of the pneumatic air excavator100may be coaxially arranged such as the nozzle130, barrel140, portions of the actuator assembly150, the releasable coupling160, a safety mechanism165and the primary flow valve170. A primary flow passage105of the pneumatic air excavator100may extend along a central axis thereof and may be defined at least by the flow valve170, the barrel140and nozzle130.

At the proximal end110of the air excavator100, a port or fitting112may be provided for removably connecting to the air supply via the delivery line111to establish a fluid coupling to the air supply. For instance the delivery line111may include a fitting that is complementary to the fitting112, or the two may otherwise be configured for coupling to one another directly or indirectly to provide an air tight connection. For instance, the fitting112may be a quick connect fitting, a claw connector such as a Chicago claw connector, or other air supply connection. The proximal end110may optionally include an angled conduit or pipe113and/or a straight conduit or pipe114, each of which may for instance facilitate ergonomics of using the pneumatic air excavator100when coupled to the delivery line111. Alternatively, the port or fitting112may be positioned at a distal end120of the air excavator100, as shown inFIG.2D, and for instance may be arranged distal to the actuator assembly150and the releasable coupling160. In such case, the barrel140extending between the proximal and distal ends110,120may enable the releasable coupling160to be moved to various positions along the barrel140and locked thereto, and this portion of the barrel140, in some instances, may not receive airflow from the air supply, and may thereby provide flexibility in the configuration of the releasable coupling160and the barrel140. Arrangement of the port or fitting112at the distal end120may lower the center of gravity of the pneumatic excavator to a more centralized position, for instance to provide better ergonomics and reduce fatigue. In such examples, the barrel140may be arranged both at the inlet end179of the flow valve170and the outlet end178of the flow valve170as shown inFIG.2D.

The distal end120of the pneumatic air excavator100may define an outlet and may include a nozzle130coupled thereto. For instance, the nozzle130may be coupled to an egress of the barrel140, and the nozzle130may define an outlet for the pneumatic excavator100. The nozzle130may have various configurations depending on the desired delivery pressure and flow geometry emitted therefrom. For instance, the nozzle130may have a supersonic nozzle design. The nozzle130may be constructed of various materials such as metal including brass, stainless steel, composites such as polymers, reinforced polymers, a combined construction of metallic and polymer materials, and combinations thereof. The type of nozzle may include but is not limited to 30-300 cubic feet per minute (cfm) at 70 to 250 psi. The nozzle130may be interchangeable with other nozzles and may be releasably coupled to the distal end120such as via a threaded engagement or other fastening mechanism, e.g., quick connect. Alternatively, the nozzle130may be non-detachably connected to the distal end120of the pneumatic air excavator100. In addition or alternatively, the nozzle130may include a non-conductive cover or coating, e.g., a rubber, polymer, of the like, for protecting the air excavator100and user from electrical shocks during excavation operations near power sources.

In some implementations, the distal end120of the pneumatic air excavator100may be formed of an optional barrel extension122as illustrated inFIG.1. The barrel extension122may have the same or a different configuration as the barrel140of the pneumatic air excavator100and may be detachably coupled to the barrel140such as via a threaded collar or via another fastening mechanism such as those disclosed herein. The barrel extension122may enable the user P to use the pneumatic air excavator100in excavation applications at varying depths, and for instance, a longer extension122may be joined to the barrel140when the target object has a depth that is deeper than the length of the barrel140. This may enable the user P to operate the pneumatic air excavator100more comfortably, as the user may operate the system in a standing position instead of a kneeling or bent position. In some implementations, the extension122and the barrel140may be telescopically arranged, and the length of the pneumatic air excavator100may be adjustable, such as by operating an adjustment collar that permits telescopic movement of the extension122relative to the barrel140. The extension122may be constructed of the same or different material from the barrel140, and for instance may be constructed of a non-conductive material such as fiberglass, plastics, rubbers, polymers, lined or coated material, aluminum, and so on.

The barrel140may define a portion of the primary flow passage105of the pneumatic air excavator100for delivering compressed air to the nozzle130. The barrel140may be configured as a rigid, elongated tubular conduit having an ingress and an egress, and the ends may be coupled to various components as described herein, e.g., the ingress may be coupled to the delivery line111and the egress may be coupled to the nozzle130in a detachable or non-detachable manner. The barrel140may be constructed of a non-conductive material such as fiberglass, plastics, rubbers, polymers, lined or coated material, aluminum, and so on. In some implementations, an adjustable shield142may be slidably arranged on the barrel140proximate the distal end (FIG.2C). The adjustable shield142may be cone-shaped and may deflect debris during an excavation operation.

The actuator assembly150of the pneumatic air excavator100may be arranged along the barrel140as shown inFIGS.2A,2C and2D. The actuator assembly150may generally include an actuation switch and may be releasably coupled to the barrel140by the releasable coupling160described herein. The actuation switch of the actuator assembly150may include a trigger151, e.g., a push button, coupled to a trigger valve152. The trigger151may be biased by a biasing mechanism such as a spring or a solenoid valve. For instance, the trigger valve152may include a spool valve with a spool and spool pilot, where the spool is biased by a biasing mechanism such as a spring or solenoid valve, and the trigger151may move the spool against the bias force of the biasing mechanism. An actuation conduit153may at least be coupled between the actuator assembly150and the flow valve170and between the safety mechanism165and the actuator assembly. The actuation conduit153may be movably adjustable as provided herein and may include one or more conduits such as air hoses or conductive wires.

Operation of the actuation switch may cause the pneumatic air excavator100to be turned on and off. For instance, to activate the actuator assembly150, the actuation switch may be moved to a closed position, e.g., by depressing the trigger151. In response, the actuation conduit153coupled between the actuator assembly150and the flow valve170sends a signal to cause the main valve170to move to an open position, such that compressed gas from the delivery line111is permitted to pass through the main valve170as well as the primary flow passage105of the pneumatic air excavator100such that the compressed air exits through the nozzle130. The actuator assembly150may be deactivated or released by the actuation switch moving to an open position, e.g., by releasing the trigger151. Where the trigger151includes a biasing mechanism, deactivation may cause the trigger151to move to a normal position where the biasing mechanism, e.g., a return spring, is relaxed. In response, the actuation conduit153may send a signal to cause the flow valve170to move to a closed position to prevent the compressed gas from passing through the main valve170and thus the primary flow passage105. The actuation conduit153may be a flexible conduit that can be extended and retracted along the barrel140of the pneumatic air excavator100. For instance, the actuation conduit153may be configured as flexible air tubing (e.g., an air actuation conduit), as a flexible electrical conduit (e.g., a conductive wire), and may be coiled around the barrel140, strung along the barrel140, e.g., between the actuator assembly150and the flow valve170, or may be telescopic along the barrel140. In some implementations, a sleeve may cover the actuation conduit153. The actuation conduit153may be provided as one or more conduits. For instance, one, two, three, four, five six, seven or more conduits may be provided in the actuation conduit.

Although the actuator assembly150is illustrated as being positioned on the releasable coupling160, the actuator assembly150may alternatively be positioned on the flow valve170or another portion of the pneumatic air excavator100. In addition or alternatively, although the actuator assembly150is illustrated as being positioned distal to the flow valve170, the actuator assembly and, in some cases, the releasable coupling160carrying the actuator assembly150, may alternatively be positioned proximal to the flow valve170of the pneumatic air excavator100.

The releasable coupling160may be configured to releasably couple the actuator assembly150to the barrel140in a plurality of locked positions along a length of the barrel140when in a released position, and may be locked or fixed to the exterior141of the barrel140in the locked position. The releasable coupling160may include a sleeve-shaped portion161(FIG.3) surrounding the barrel140, which may be locked and unlocked by a locking mechanism162such as a clamp or a cam lock, e.g., clamping handle coupled to a split ring or clamp, for establishing a pinch, compression, and/or friction lock. The locking mechanism162may engage with the barrel140via a pinch or clamping mechanism along the external diameter of the barrel140. In an unlocked position of the locking mechanism162, the releasable coupling160may be in a released position and be moved or slid along the exterior141of the barrel140, and due to the actuation conduit153being adjustable or flexible, movement of the releasable coupling160slaves the actuation conduit153along the barrel140of the pneumatic air excavator100(e.g., in an expansion or a retraction movement) and thus the coupling between the actuator assembly150and the flow valve170via the actuation conduit153can be maintained in any position of the actuator assembly150relative to the flow valve170. The locking mechanism162of the releasable coupling160may be moved to a locked position to secure or lock the releasable coupling160to the exterior141of the barrel140.

In some implementations, the sleeve-shaped portion161of the releasable coupling160may include the trigger151of the actuator assembly150coupled thereto, and for instance the trigger151may be arranged on or in the sleeve-shaped portion161to provide a user with a grippable portion via the sleeve-shaped portion that can be simultaneously used to actuate the actuator assembly150via the trigger151between an on and off state. In some implementations, the releasable coupling160may additionally include a handle163(FIGS.5A and5B), which may extend from the sleeve-shaped portion161and/or may be integrated with the sleeve-shaped portion161. As shown inFIGS.5A and5B, the trigger151of the actuator assembly150may be integrated with the handle163of the releasable coupling160and the trigger151may be movable between an off position (FIG.5A) and an on position (FIG.5B). In some implementations, the handle163may be positioned perpendicularly, at an angle, or parallel relative to the releasable coupling160and the barrel140. In addition, the handle163may be an adjustable handle that is adjustable to the aforementioned positions. It will be appreciated that the actuator assembly150and releasable coupling160may be integrated into an assembly configured to be held or gripped by a single hand of the user P to facilitate ergonomics and use of the pneumatic air excavator100. In further implementations, a second handle143(FIG.2C) may be releasably coupled to the barrel140using a second releasable coupling144, e.g., a cam lock or clamp, and may be configured to be movable to a plurality of locked positions along the length of the barrel140independent from the releasable coupling160.

In some implementations, a safety mechanism165may be included with the air excavator100configured to require actuation of primary and secondary actuators for the pneumatic excavator100to operate, which actuators may be arranged such that both hands of a user are required for actuation, e.g., by depressing the two actuators using separate hands. This may ensure that the operator always has two hands on the pneumatic excavator100during operation and reduces the chances of an accidental discharge. Accordingly, the safety mechanism165may include a secondary trigger or actuator166, which may be operated in combination with the actuator150(e.g., the actuation switch or trigger151) in order for the user to operate of the pneumatic excavator100. The actuator150is also referred to as a primary actuator for purposes of discussion in connection with the secondary actuator166. Depressing both the primary and secondary actuators150,166, respectively, may result in completion of a circuit that enables the flow valve170to receive a signal that causes movement to the open position (FIG.4B) and flow of air through the primary passage105. In such examples, depressing only one of the primary and secondary actuators150,166may result in the flow valve170remaining in a closed position or moving to a closed position (FIG.4A) for instance due to providing an incomplete circuit, such that the flow valve170is held in a closed position and/or is prevented from receiving a signal that otherwise can cause movement to the open position. The safety mechanism165may be coupled to the primary actuator150via the conduit153, which may include an air hose154d(FIG.2B) and for instance the signal may be an air signal, such as compressed air. Alternatively, the conduit153may be configured to carry an electrical signal. The safety mechanism165may be arranged along the barrel140in a separate location from the actuator150. In some implementations, a releasable coupling160′ (FIG.2A), e.g., a second releasable coupling, may include the safety mechanism165or components thereof integrated therein, and the releasable coupling160′ may be used to lock the safety mechanism165to the barrel140. For instance, as shown inFIG.2B, the actuator166of the safety mechanism may be provided on the releasable coupling160′ and arranged along the barrel140in a location separate from the other releasable coupling160and the primary actuator150. Accordingly the releasable couplings160,160′ and their respective trigger151and actuator166may be movable relative to each other along the length of the barrel140.

The flow valve170also referred to as a primary valve or main valve of the pneumatic excavator100may be arranged between the pipe114and the barrel140as illustrated inFIGS.4A and4Band may be responsible for delivering airflow through the pneumatic air excavator when in the actuated or open position. Referring toFIGS.3,4A and4B, the flow valve170may include ports171a,171b,171c,a piston175, a valve seat176, an outlet end178and an inlet end179, where the portion of the flow valve170defining the primary flow passage105extends therebetween. In some implementations the flow valve170may be free of a return spring, such as where the flow valve170is pneumatically operated, while in other implementations, a mechanical biasing mechanism such as a return spring may be included in the flow valve170. The flow valve170may be configured as a pneumatically piloted valve such as a coaxial valve, a double acting coaxial valve, or as a solenoid actuated coaxial valve, as a pneumatic actuated angle seat valve or as a pneumatically actuated ball valve.

Ports171a,171b,and171cof the flow valve170may be coupled to the actuator assembly150via the actuation conduit153. For instance, referring toFIGS.2B and3, the actuation conduit153may include at least two flexible air hoses, such as three air hoses154a,154b,and154c.Air hose154amay be configured as a constant pressure conduit, a first end of which may be coupled to the pneumatic air excavator100at a port171aupstream from the piston175of the flow valve170, and the air hose154amay extend to and be coupled to the actuator assembly150, e.g., at port158a,at a second end. Although the port171ais illustrated as being defined in the flow valve170, it will be understood that the port171amay be defined in other portions of the pneumatic excavator100upstream from the flow valve170. The air hose154amay be constantly supplied compressed air when the delivery line111transmits pressurized air. Air hoses154b,154cmay each be coupled to respective other ports171b,171cof the main valve170and to respective ports158b,158cof the housing157of the actuator assembly150.

In implementations of use, the pneumatic air excavator100may be pneumatically turned on and off using the same compressed air supply that is used to operate the pneumatic air excavator100. For instance, the actuation conduit153may include air hoses, e.g., air hoses154a,154b,and154c.The air hoses may receive compressed air from the delivery line111or may carry compressed air emitted from the actuator assembly150to the flow valve170. For instance, the compressed air received by the actuator assembly150may be derived from the air supply from the delivery line111, and thus the actuator assembly150may receive the same compressed air supply that is used to operate the pneumatic air excavator100, e.g., when the flow valve170is open and the compressed air passes through the primary flow passage105.

In such implementations, actuation of the trigger151of the actuator assembly150may open a valve of the trigger valve152, e.g., by movement of a spool against a biasing mechanism such as a return spring, to cause pressurized air from the actuator assembly150to enter the actuation conduit153, e.g., air hose154c,fluidly coupled to the main valve170, and the actuation conduit153may deliver the pressurized air to a port, e.g., port171c,of the main valve170to cause the main valve170to open and thereby permit pressurized air to flow through primary flow passage105of the pneumatic air excavator100. Release of the trigger151may cause the trigger valve152to relax, for instance as a biasing force is released such as via relaxation of a spring, which may also cause pressurized air from the air supply to enter the actuation conduit153, e.g., at air hose154b,and be delivered to the main valve170, but the pressurized air may be routed to another port, e.g., port171bof the main valve170to close the main valve170and thereby prevent pressurized air from flowing through the primary flow passage105and exit the nozzle130. Thus, the actuator assembly and the air hoses of the actuation conduit153may be configured to enable the actuator assembly150to pneumatically actuate and deactivate the pneumatic air excavator100.

In implementations of use, the releasable coupling160may be movable along the barrel140at various stages of use of the pneumatic air excavator100. For instance, the releasable coupling160may be used to adjust the position of the actuator assembly150prior to delivering compressed air through the delivery line111, however, the releasable coupling160may be operated while the compressed air111is active. In examples, the trigger151of the actuator assembly150may be in an open, un-depressed state, the releasable coupling160may be unlocked, moved to a selected position, locked to the barrel140, and then the trigger151may be depressed in an excavating operation. In other examples, the trigger151may be depressed in connection with an excavating operation while the releasable coupling is unlocked, moved to a new position, and locked to the barrel140.

In some implementations of use, at least a portion of the actuator assembly150and releasable coupling160may be held by one hand of the user P to turn on and off the pneumatic air excavator100. Due to the releasable coupling160being movable, the pneumatic air excavator100may be simplified because the user is allowed to select where along the barrel140to the actuator assembly150should be positioned and operated, for instance, depending on how the pneumatic air excavator100is being used or intended to be used, and move the releasable coupling160to the selected position. In addition to selecting where the user's hand will be on the air excavator100when operating the actuator assembly150, this flexibility may also facilitate operation due to the ability to adjust and select where the user's other hand is positioned on the pneumatic air excavator100relative to the other hand on the actuator assembly150. Thus, the releasable coupling160may provide an ergonomic approach to air excavation and operational control that has not otherwise not been possible.

With reference toFIGS.6A-6C, the pneumatic excavator100may include the safety mechanism165configured to receive an air signal such as compressed air. In this case, the secondary actuator166may be configured as a valve for receiving and transmitting compressed air, such as a spool valve. The secondary actuator166may be actuated, for instance, using a trigger of the secondary actuator166. The secondary actuator may be fluidly coupled to at least one air conduit. For instance, the actuator166may include an intake port168aconfigured to constantly receive compressed air, such as from a constant pressure conduit154a′ configured to receive compressed air from a port upstream of the flow valve170, and may be configured with a delivery port168bfor coupling via an air delivery conduit169to a shuttle valve167a,as well as another delivery port168cfor coupling via an air delivery conduit to an intake port150athe primary actuator150. For instance, the air hose154dmay be configured as a constant pressure conduit configured to conditionally receive an air signal from the constant pressure conduit154a′ such as when the secondary actuator166is in an actuated or closed position.

FIG.6Aillustrates an initial state of the secondary actuator166of the safety mechanism165prior to actuation, such as in a normal position of the secondary actuator166configured as a valve spool biased by a biasing mechanism. In the initial state, the pressure signal entering the secondary actuator166may be routed into the shuttle valve167a.The shuttle valve167amay include an entry or intake port on each side167b,167c,and a separate exit or delivery port167d, e.g., on the bottom. The shuttle valve167amay allow air flow through the entry port with the higher pressure, and blocks the entry of air flow into the entry port having the lower pressure. InFIG.6A, the intake port167bof the shuttle valve is pressurized via air delivery conduit169, e.g., an air hose, and the intake port167cis vented back to atmosphere at this phase via, flow is allowed from the intake port167bto the exit port167dand the intake port167cis blocked-off. The pressure signal from the exit port167dof the shuttle valve167ais directed into the port171bof the main valve170, ensuring that the main valve170remains shut while both actuators166,150are in the initial state or normal position. The shuttle valve167amay prevent the pressure signal from the secondary actuator166from looping back through primary actuator150and venting to atmosphere. At this phase, if the primary actuator150was actuated but not the secondary actuator166, no change would occur since no pressure signal is provided at the intake port150aof the actuator150. In addition, any entrapped air at the port171cof the main valve170may be vented through vent port159aof the actuator assembly150via the air hose154c.

With reference toFIG.6B, once the secondary actuator166is actuated, e.g., depressed, the pressure signal may instead be routed into the entry or intake port150aof the primary actuator150for instance via a conduit or air hose154dconfigured to conditionally receive an air signal from the constant pressure conduit154a′ when the secondary actuator166is actuated. In the state ofFIG.6B, the conduit154dmay also function as a constant pressure conduit by receiving a constant supply of compressed air when the delivery line111is transmitting pressurized air to the pneumatic excavator100. If the primary actuator150is in the initial or normal position, then the pressure signal may be routed into the shuttle valve167a.At this phase the intake port167bof the shuttle valve is routed to atmosphere, so the pressure signal at the other intake port167cis passed to the exit or delivery port167d,and the intake port167bis blocked. Again, the pressure signal at the exit port167dmay be routed to the port171bof the main valve170, ensuring that the main valve170remains shut even if one of the two actuators is depressed. In addition, any entrapped air at the port171cof the main valve170may be vented through vent port159aof the actuator assembly150via the air hose154c.

With reference toFIG.6C, a next phase of operation is illustrated when both the primary and secondary actuators150,166are actuated. With the secondary actuator166depressed the air signal is routed into the entry or intake port150aof the actuator150. With the actuator150actuated, e.g., the trigger151depressed, the air signal may then be routed into the port171cof the main valve170thereby forcing the main valve170into an open position. Entrapped air in the main valve170received from port171bmay then exit this port171band be routed through the shuttle valve167aand vented through one of the actuators166,150, e.g., at vent port159bof the primary actuator150and vented to atmosphere.

According to implementations of use, as shown in the flow diagram ofFIG.7, a method300of operating a pneumatic excavator100including a safety mechanism165may involve, in operation310, supplying compressed air to the pneumatic excavator100from a compressed air supply, e.g., via delivery line111. The method300may continue by actuating the primary actuator150and the secondary actuator166of the safety mechanism165in operation320to cause compressed air to be transmitted from the secondary actuator166to the primary actuator150and then to the flow valve170to cause the flow valve170to move to an open position (FIG.4B) such that the compressed air from the supply of compressed air passes through the primary flow passage105and exits the pneumatic excavator100. Actuating one of the primary or secondary actuators150,166and not actuating the other in operation330may cause the compressed air to be transmitted to the shuttle valve167ato the flow valve170to cause the flow valve170to move to a closed position (FIG.4A) such that the compressed air from the supply of compressed air is prevented from passing through the flow valve170.

For instance, in operation310, the compressed air may be supplied via delivery line111to the inlet end179of the flow valve170such that the compressed air enters the constant pressure conduit154a′ and is received by an intake port of the secondary actuator166of the safety mechanism165.

Prior to actuation of the actuators in operation320of method300, the compressed air supply may be prevented from passing through the barrel140and exiting the nozzle130due to the flow valve170being in a closed position (FIG.4A) and the primary or secondary actuator150,166routing pressurized air to the shuttle valve167a,which transmits the compressed air to the flow valve170to retain or move the piston175to seal against a valve seat176of the flow valve170(FIG.4A). For instance, the constant pressure conduit154a′ may receive the compressed air from the port171apositioned upstream of the piston175such that the compressed air is permitted to constantly pass through the constant pressure conduit154a′ and to the secondary actuator166as long as the delivery line111is supplied with compressed air. Where the secondary actuator166is open, e.g., unactuated, the compressed air is routed from the secondary actuator166to the port171bof the flow valve170via the exit port167dof the shuttle valve167ato close or retain the flow valve170in a closed position. Where the secondary actuator166is closed, e.g., actuated, but the primary actuator150is open, e.g., unactuated, the compressed air is received at the primary actuator150from the air hose154d,e.g., configured as a conditional constant pressure conduit, but again is routed to the port171bof the flow valve170via the exit port167dof the shuttle valve167a,to again close or retain the flow valve in the closed position. Thus, the pneumatic excavator100is provided with a safety mechanism permitting operation, e.g., air flow through the primary flow path105, only when both actuators are actuated.

Returning to method300, upon actuating the primary actuator150and the secondary actuator166in operation320, the actuator assemblies may each move to a closed position, and compressed air may be transmitted from the constant pressure conduit154a′, air hose154dand through the air hose154cof the actuation conduit153, to the flow valve170to cause the flow valve170to move to an open position (FIG.4B) where the compressed air from the compressed air supply passes from the delivery line111and through the primary flow passage105of the pneumatic excavator100and exits the nozzle130. In the open position of the flow valve170, the piston175is pushed away from the valve seat176to permit air to pass through. In this state of the actuators150,166, the shuttle valve167amay not receive compressed air. For instance, when both actuators150,166are first depressed and the piston175shifts to the open position there may be an initial venting of air from port171b,which may exit shuttle valve171aand to atmosphere. After this initial venting the shuttle valve171amay remain open to atmosphere on both intake ports until one or both of the actuators150,166, e.g., triggers151and/or trigger of the secondary actuator166, has been released.

Releasing one or the other primary or secondary actuator150,166, e.g., while keeping the other actuated in operation330, may result in the airflow from the constant pressure conduit154a′ being routed to the shuttle valve167ato thereby cause the flow valve170to again move to the closed position (FIG.4A). For instance, during the actuating of one of the primary actuator150or the secondary actuator166and not actuating the other, the shuttle valve167aallows air to enter one entry port167bor167cfrom the actuated actuator and prevents air from entering the other entry port. In some implementations, the flow valve170is a pneumatic valve requiring the delivery of compressed air to one of its ports171band171cin order to open and close, and accordingly the flow valve170may be free of a biasing mechanism such as a return spring.

Accordingly, the actuator assembly150and safety mechanism165may together be configured to pneumatically actuate the flow valve170via completion of an air circuit from the constant pressure conduit154a′ to the flow valve170via the air hose154dand the air hose154c, as provided herein. In addition, as provided herein, the actuator150and the safety mechanism165may be remotely arranged from each other and from the flow valve170as illustrated in the Figures. Pneumatically actuating the pneumatic air excavator100may provide advantages because use of pressurized air as a means to trigger the flow valve170provides an efficient use of pressurized air at the safety mechanism165and the actuator assembly150where a small air signal may be used, e.g., via the safety mechanism165and actuator assembly150including the aforementioned conduits, results in a short throw length or relay to cause a large pressure change at the flow valve170to cause the flow valve170to close and open (FIGS.4A and4B). A coaxial-style valve as illustrated in these figures, as well as other pneumatic valves such as ball or angled seat, may thus be operated using a small mechanical operator, like the trigger151and secondary actuator166, to cause pressurized air to flow through the flow valve170as provided herein.

Venting may occur during operation of the compressed air excavator100to cause opposing pressure to be vented to the atmosphere. In some implementations, the flow valve170may be vented via one or more ports171b,171cwhen the valve is in the open and/or closed position to facilitate reliable operation of the pneumatic air excavator in the on and off positions. For instance, when the flow valve170is in the closed position ofFIG.4A, e.g., due to the compressed air from air hose154bentering port171bof the flow valve170and forcing the piston175against the valve seat176, any entrapped air present in the port171cmay be vented, for instance through the air hose154cand to an exhaust port159a(FIG.3) of the actuator assembly150. Similarly, when the flow valve170is in the open position ofFIG.4B, e.g., due to the compressed air from the air hose154centering port171cof the flow valve and forcing the piston175away from the valve seat176, any air present in the port171bmay be vented, for instance through the air hose154band to the exhaust port150of the actuator assembly150. In addition or alternatively, entrapped air in the main valve170received from port171bmay exit this port171bwhen the flow valve170is moved to an open position, and the entrapped air may be routed through the one of the actuators166,150, e.g., through exhaust or vent ports described herein and vented to atmosphere. In some implementations, the flow valve170may include a mechanical biasing mechanism such as a return spring to facilitate movement of the piston175to the closed position.

In some implementations, the actuator assemblies and the controller valves may be biased such as spring loaded. For instance, depressing the trigger151against a spring force may cause trigger valve152to shift from its initial or normal position and the flow valve170to move to an open or on position as provided herein. When the trigger151is released, the spring relaxes and may cause the trigger valve152to shift back to its initial or normal position, which may cause the flow valve170to move to the closed or off position as provided herein.

Various changes may be made in the form, construction and arrangement of the components of the present disclosure without departing from the disclosed subject matter or without sacrificing all of its material advantages. The form described is merely explanatory, and it is the intention of the following claims to encompass and include such changes. Moreover, while the present disclosure has been described with reference to various embodiments, it will be understood that these embodiments are illustrative and that the scope of the disclosure is not limited to them. Many variations, modifications, additions, and improvements are possible. Functionality may be separated or combined in blocks differently in various embodiments of the disclosure or described with different terminology. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure as defined in the claims that follow.