Patent Application
20110268503
The present invention relates to an adjustment mechanism for adjusting the position of an adjustable machining tool, such as a drum, in a degradation machine.
Examples of prior art height adjustment mechanism for milling drums are disclosed in U.S. Pat. No. 3,767,264 to Eckey, U.S. Pat. No. 4,103,973 to Cutler, U.S. Pat. No. 4,961,173 to Sehr which are all herein incorporated by reference for all that they contain.
In one aspect of the invention, a degradation machine comprises motorized vehicle supported by a plurality of translation elements. A rotary degradation drum is attached to the vehicle. At least one device provides a subsurface boundary profile. An adjustment mechanism continuously adjusts a drum position to maintain a distance of the drum from the subsurface boundary profile.
The adjustment mechanism may comprise an adjustment arm that is in mechanical communication with an axle of the drum. The adjustment arm may comprise multiple layers of piezoelectric material. The adjustment arm may comprise multiple layers of magnetostrictive material. The adjustment arm may comprise multiple layers of electrostrictive material, conducting polymers, dielectric elastomers, or combinations thereof. The adjustment arm may comprise a linear screw actuator. The adjustment arm may comprise a hydraulic system comprising a piston connected to the axle of the drum.
The machine may be a mining machine or a road milling machine. The axle of the drum may be substantially normal to an underside of the machine. The axle of the drum may be substantially perpendicular to an underside of the machine. The at least one device may be a ground penetrating radar. The at least one device may be a GPS mounted on the machine. The at least one device may be a remote database with the subsurface boundary knowledge. The at least one device may be an acoustic sensor mounted in front of the machine.
In another aspect of the invention, a method of continuously adjusting a rotary degradation drum position of a motorized vehicle comprises the steps of providing a degradation drum attached to a degradation machine, determining a subsurface boundary profile and continuously adjusting the depth of cut to maintain a distance of the drum from the subsurface boundary profile by adjusting mechanism.
The subsurface boundary may be a boundary of a coal or mineral seam. The subsurface boundary may be a boundary between layers of pavement. Torque applied to the drum may continuously change with respect to the depth of cut. The adjustment mechanism may adjust the position of the drum to maintain a distance above the reference, below the reference or combinations thereof. The adjustment mechanism may adjust the position of the drum horizontally, vertically, or combinations thereof. The subsurface boundary profile collected by the at least one device may be communicated to the adjustment mechanism via a control unit. The adjustment mechanism may comprise a hydraulic accumulator controlled by the control unit.
a is a diagram of an embodiment of a degradation machine.
b is a prior art diagram of a milling procedure.
a is a cross-sectional diagram that shows a plurality of degradation assemblies 101 attached to a driving mechanism 102, such as a rotatable drum attached to the underside of a pavement milling machine 103. The milling machine 103 may be a planer used to degrade man-made formations 104 such as pavement prior to placement of a new layer of pavement. The degradation assemblies 101 may be attached to the drum 102, bringing the degradation assemblies 101 into engagement with the formation 104. A holder, such as a block welded or bolted to the drum, is attached to the driving mechanism 102 and the degradation assembly is inserted into the holder. The holder may hold the degradation assembly 101 at an angle offset from the direction of rotation, such that the degradation assembly engages the formation 104 at a preferential angle. The arrow 105 shows the machine's direction of travel.
b discloses a prior art milling procedure of a road surface structure. In the prior art, the depth of cut is controlled by using the top surface layer 120 as a reference layer. For example, a contractor will is hired to take an inch off the top of a paved surface. However, as shown in
For example, roads originally made of cement slabs are often covered with a layer of asphalt after the cement slabs have shifted over time. The shifted slabs cause the asphalt layer 130 to have a non-uniform thickness that is unknown to the contractor. Cement is much harder than asphalt. Often, if a contractor mills into the cement slabs at the same speed and toque as the when milling the asphalt, the contractor's milling equipment may risk serious damage. The cement slabs 140 may shift from their original position horizontally, vertically, angularly, or combinations thereof. The degradation assemblies 101 may follow at a uniform depth of cut as it proceeds forward as illustrated by the dashed lines 150 in the figure.
In some embodiments, electromagnetic impulses of UHF and/or VHF frequency may be emitted from the moving antenna and propagated into the ground. Impulses 200 may be reflected at subsurface boundaries 160 where density changes. Reflected impulses may be detected by the antenna receiver and digitally stored for data processing and interpretation. The GPR method may be non-destructive, revealing subsurface detail without requiring coring, breaking out or other destructive actions. The information collected by the device 210 may be fed to an adjustment mechanism via a control unit.
In other embodiments, the road may be scanned before milling and a subsurface boundary location along the road may be stored off site. The milling machine may be in wireless/remote communication with a database containing information about the subsurface boundary as the machine mills. In such embodiments, the machine may be equipped with a location device, such as a global positioning system unit that is adapted to communicate with satellites to identify its location. Thus, the machines may integrate its knowledge of changing location and the databases subsurface boundary profile as the machine moves. In some embodiments, the database may be stored directly on the machine.
The adjustment mechanism may continuously adjust the position of the drum 102 to maintain a distance of the drum 102 from the subsurface boundary profile. As opposed to the prior art, where the depth of cut is maintained from the top surface, the present invention uses the subsurface boundary as the reference for positioning the drum. The drum may be positioned at a uniform distance above or below the subsurface boundary profile, or in some embodiments, the contractor may desire to cut along the boundary.
The adjustment mechanism may raise the position of the drum 102 to maintain its distance from the subsurface boundary between the asphalt 130 and cement slabs 140 as illustrated in
The degradation assemblies 101 may penetrate deeper into the formation while adjusting its distance from the subsurface boundary 160. In some embodiments, the degradation assemblies 101 may experience more resistance as it goes deeper into the formation. High resistive forces may cause failure of the degradation assemblies 101. To avoid such failure, the adjustment mechanism continuously changes torque applied to the degradation assemblies 101 with respect to the depth of cut.
In the prior art, the milling drum's height, which determines the depth of cut, is generally adjusted periodically by adjusting hydraulic cylinders position above the tracks of the machine.
In some embodiments, the adjustments in the drum's position may only need to span within a few inches. Thus, the adjustment mechanism may be designed for small, but precise, adjustments. Preferably, the adjustments mechanism responds instantaneously to follow the subsurface boundary's profile precisely.
Referring now to
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.
