Patent Application
20120038203
The present invention relates to the field of formation degradation and more specifically pavement milling. A milling machine may comprise a driving mechanism populated with a plurality of degradation assemblies, typically picks or cutters, which may degrade natural or man-made formations such as pavement, concrete, or asphalt when the driving mechanism is rotated while in contact with the formation. During normal milling operation, the degradation assemblies are often damaged due to coming into contact with hard materials buried underneath or located on the surface of the formation. The prior art discloses milling assemblies for improving the service life of said degradation assemblies.
One such milling assembly is disclosed in U.S. Pat. Pub. No. 2008/0284235 to Hall et al., which is herein incorporated by reference for all that it contains. Hall et al. discloses an apparatus for degrading natural and man-made formations including a pick with an axially spring loaded pick comprising a central axis and being attached to a holder secured to a driving mechanism. The pick comprising a steel body with an axial shank disposed within a bore of the holder. A spring mechanism may be built into the holder which allows the tip to engage the formation and then recoil away from the formation lessening drag that would otherwise occur on the tip. The recoiling effect is believed to reduce wear caused from the drag. The recoiling effect is also believed to degrade the formation in larger chunks than dragging the tip against the formation surface. The spring mechanism may comprise a coil spring, a compression spring, a tension spring, Belleville spring, wave spring, elastomeric material, gas spring, or combinations thereof. The pick may also comprise an axial shank which is press fit into the holder. The shank is secured within a holder which is secured to the driving mechanism.
Another such milling assembly is disclosed in U.S. Pat. No. 4,175,886 to Moench et al., which is herein incorporated by reference for all that it contains. Moench et al. discloses an asphalt cutting apparatus for breaking up and windowing old asphaltic pavement on a roadway or the like including the pavement adjacent to a curb or gutter. A plurality of laterally spaced, sharpened cutter discs are freely rotatably mounted on a support carriage. The support carriage is attached to a frame pivotally coupled at a forward pivot to a prime mover such as a truck or similar vehicle for movement along the asphalt surface. As the cutter discs are moved along the asphalt surface a hydraulic clamp cylinder provides a vertical movement about the forward pivot to vary the depth of cut and also maintains a downward pressure on the cutter discs and forces the discs to roll through and cut up the asphalt. The construction and mounting of the support carriage is such that the discs are adjustable movable laterally axially along a horizontal axis for selective positioning adjacent to a curb or gutter and are further adjustable movable about a pivot to slope laterally outwardly and downwardly so that the discs are positioned at different cutting depths relative to one another for cutting an asphalt surface that is sloped for drainage purposes.
In one aspect of the present invention a pick assembly comprises a rotatable drum comprising at least one block disposed on a circumferential surface of the drum wherein the at least one block comprises a cavity comprising a cylinder, and a pick comprising a working end and an opposing base end wherein the base end is disposed within the cavity and comprises a piston that is slidably retained within the cylinder.
The piston may define first and second pressure chambers within the cylinder wherein a first fluid channel may be in fluid communication with the first pressure chamber and a second fluid channel may be in fluid communication with the second pressure chamber. At least one valve may alternately connect the first and second fluid channels to a pressurized fluid channel and a relief fluid channel. The pick may comprise an expanded axial position when the pressurized fluid channel is in fluid communication with the second fluid channel and a retracted axial position when the pressurized fluid channel is in fluid communication with the first fluid channel.
In another embodiment, the first pressure chamber may comprise a first surface and the second pressure chamber may comprise a second surface wherein the second surface is substantially greater than the first surface. The first fluid channel may be connected to the pressurized fluid channel while the at least one valve alternately connects the second fluid channel to the pressurized fluid channel or the relief fluid channel. The pick may expand when the second fluid channel is connected to the pressurized fluid channel due to the difference in size between the first surface and the second surface.
The at least one valve may be controlled by a mechanical actuator comprising a linear solenoid, a rotary solenoid, or a hydraulic motor. The mechanical actuator may be in communication with an electronic circuit which my read data, redirect power, and send information about the position of the at least one valve through an armored coaxial wire.
The rotatable drum may comprise a plurality of blocks disposed on a circumferential surface of the drum. Each block may be connected to a unique electronic circuit and a single armored coaxial wire may connect all unique electronic circuits together.
In another embodiment of the present invention a pick assembly may comprise a rotatable drum comprising a cavity within the drum, the cavity comprising a cylinder. At least one block may comprise a first end and an opposing second end wherein the second end is disposed within the cavity and comprises a piston that is slidably retained within the cylinder. A pick comprising a working end is rigidly secured to the first end of the at least one block.
In another embodiment of the present invention a method of milling a surface with a pick assembly comprises sending an electrical signal through a single armored coaxial wire to a piston cylinder device instructing the piston cylinder device to expand or retract. The method may further comprise sending an electrical signal through the single armored coaxial wire to independent piston cylinder devices instructing the piston cylinder devices to expand or retract independently. Each piston cylinder device may comprise a unique identifier signal wherein the piston cylinder device recognizes the identifier signal when it is sent through the single armored coaxial wire.
The method may further comprise providing an object detection system, passing the object detection system over a surface, and detecting at least one object on or beneath the surface with the object detection system. An electrical signal may be sent comprising information about the detected at least one object. The rotatable drum may pass over the surface and the piston cylinder device may retract to avoid making contact with the detected at least one object. The object detection system may comprise ground penetrating radar or a metal detector. The step of retracting the piston cylinder device to avoid making contact with the detected at least one object may comprise retracting the piston cylinder device automatically or manually.
The method may further comprise passing the rotatable drum over a surface, removing a portion of the surface with the at least one pick, and varying a volume of the portion removed by expanding or retracting the piston cylinder device.
An electrical signal may be sent comprising stored information about at least one object on or beneath a surface. The rotatable drum may pass over the surface and the piston cylinder device may retract to avoid making contact with the at least one object.
a is a cross-sectional view of an embodiment of a pick assembly.
b is a cross-sectional view of another embodiment of a pick assembly.
Referring now to the figures,
a discloses an embodiment of a pick assembly 106 wherein the pick 302 is in an expanded axial position. In this embodiment, the at least one valve 310 connects the pressurized fluid channel 311 to the second fluid channel 309 and the relief fluid channel 312 to the first fluid channel 308. When the pressurized fluid channel 311 is connected to the second fluid channel 309, fluid may flow into the second pressure chamber 307 and apply pressure to a second surface 402 forcing the pick 302 to expand axially. Any fluid in the first pressure chamber 306 may exit through the first fluid channel 308 and subsequently the relief fluid channel 312.
b discloses an embodiment of a pick assembly 106 wherein the pick 302 is in a retracted axial position. In this embodiment, the at least one valve 310 connects the pressurized fluid channel 311 to the first fluid channel 308 and the relief fluid channel 312 to the second fluid channel 309. When the pressurized fluid channel 311 is connected to the first fluid channel 308, fluid may flow into the first pressure chamber 306 and apply pressure to a first surface 401 forcing the pick 302 to retract axially. Any fluid in the second pressure chamber 307 may exit through the second fluid channel 309 and subsequently the relief fluid channel 312.
The at least one valve 310 may be controlled by a mechanical actuator 501 which may comprise a linear solenoid, a rotary solenoid, or a hydraulic motor. The mechanical actuator 501 may be in communication with the electronic circuit 502. The electronic circuit 502 may read data and redirect power from the armored coaxial wire 503 to the mechanical actuator 501. The electronic circuit 502 may also send information about the position of the at least one valve 310 through the armored coaxial wire 503.
The object detection system 902 may comprise ground penetrating radar to detect hard materials buried underneath or located on the surface of the formation 905. It is believed that many hard materials, such as a man-hole cover, may comprise ferrous objects. The object detection system 902 may comprise a metal detector to detect specifically those hard materials comprising ferrous objects.
Upon detecting the at least one object 906, the electrical signal may be sent directly to the pick assemblies 904 such that the piston cylinder devices will retract automatically to avoid making contact with the detected at least one object 906. The electrical signal may be sent to the information processor 908. An operator 909 may manually control the axial position of each pick 911 in the pick assemblies 904 using the information processor 908 such that the operator 909 may retract the piston cylinder devices to avoid making contact with the detected at least one object 906.
An electrical signal comprising stored information about the at least one object 906 may be sent to the pick assemblies 904. The electrical signal may instruct the piston cylinder devices to retract to avoid making contact with the at least one object 906. The stored information may come from a previous survey of the formation 905, from the operator 909, or another source.
Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.
