Patent Publication Number: US-2010122477-A1

Title: Hydraulic actuator assembly and scraper using same

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to a hydraulic actuator assembly, and more particularly to a hydraulic actuator assembly for translating linear motion into rotary motion. Such a hydraulic actuator assembly may be used to raise and lower an apron of a scraper, as described herein. 
     BACKGROUND 
     Earthmoving equipment is used to perform a variety of operations, including loading, or capturing, material, such as soil, at one location and dumping, or depositing, the material at another location. For example, such material movement may be employed to adjust elevations at a project site. Scrapers, which typically provide quick load, dump, and maneuver time, may be used to perform such operations, and generally include a machine having a bowl within which material may be captured, and a cutting edge located adjacent a cut opening of the bowl. Although various scraper configurations are available, scrapers are often pulled by a tractor, such as a wheeled or track type tractor. In addition, scrapers may provide their own traction via a separate engine that applies rim pull, or power, to the wheels of the scraper. In either arrangement, scrapers may also be pushed or pulled by a separate machine, or tractor, to provide additional power for scraper operations. 
     During a typical operation, or duty cycle, an apron of the scraper may be pivoted upward, to a raised position, to open, or unblock, the cut opening of the bowl, and also to increase the capacity of the bowl. The scraper may be pulled forward, at a material capturing location, while the cutting edge of the bowl is pivoted downward to cut through the material. The cutting edge, oriented perpendicular to the direction of travel, may also serve to guide the material into the bowl. When the bowl is loaded to some desired capacity, the cutting edge of the bowl may be pivoted upward so that the cutting edge is out of contact with the material, and the machine may be transported to a location where the soil is to be deposited. In addition, the apron may be pivoted downward, to a lowered position, to prevent loss of the material during transport. After the material is deposited, often with the assistance of an ejector mechanism, the scraper may be returned to the material capturing location, and the duty cycle may be repeated. 
     To move the apron between raised and lowered positions, mechanisms for actuating mechanical linkages attached to the apron are often employed. According to one example, as shown in U.S. Pat. No. 3,016,633, an apron sector gear is fixed to the front center portion of the apron and follows the vertical section contour of the apron. The apron sector gear is driven by an electric motor through a suitable gear reduction. The electric motor and the gear reductions are fixed to the upper forward bowl structure and move the apron between open and closed positions. Although this arrangement may provide suitable actuation of the apron, it should be appreciated that there is a continuing need for actuation mechanisms that provide smooth operation, increased position resolution, and that satisfy strict spatial requirements. 
     The present disclosure is directed to one or more of the problems set forth above. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect, an apron assembly includes an apron having an apron body extending between a first apron side and a second apron side. A portion of the apron includes an arcuate gear surface. A hydraulic actuator assembly includes a linear hydraulic actuator configured to actuate a drive gear, which is in mesh with the arcuate gear surface. 
     In another aspect, a scraper includes a scraper bowl supported on a frame of the scraper. The scraper bowl includes a first bowl side and a second bowl side. An apron includes an apron body extending between a first apron side and a second apron side. The first apron side is pivotably attached to the first bowl side, and the second apron side is pivotably attached to the second bowl side. A portion of the apron includes an arcuate gear surface. A hydraulic actuator assembly includes a linear hydraulic actuator configured to actuate a drive gear, which is in mesh with the arcuate gear surface. 
     In yet another aspect, a hydraulic actuator assembly includes a linear hydraulic actuator having a cylinder end and a rod end. A drive block is coupled with the rod end and is mounted on a drive shaft. The drive block includes at least one inwardly extending projection positioned within a helical groove of the drive shaft. At least one drive gear is supported on the drive shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side diagrammatic view of a machine, according to the present disclosure; 
         FIG. 2  is a perspective view of one embodiment of an apron assembly of the machine of  FIG. 1 , the apron of the apron assembly being shown in a raised position, according to the present disclosure; 
         FIG. 3  is a perspective view of the apron assembly of  FIG. 2 , the apron being shown in a lowered position, according to the present disclosure; 
         FIG. 4  is a perspective view of another embodiment of an apron assembly of the machine of  FIG. 1 , the apron being shown in a lowered position, according to the present disclosure; and 
         FIG. 5  is a perspective view, shown in cross-section, of a portion of a hydraulic actuator assembly of the apron assembly of  FIGS. 2 and 3  or  FIG. 4 , according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of a machine  10  is shown generally in  FIG. 1 . The machine  10 , as shown, includes a scraper  12  attached to a tractor  14  through an articulated hitch  16 . Although the tractor  14  is depicted as a wheeled tractor, it should be appreciated that scraper  12  may be attached and, thus, pulled or towed by any machine or vehicle, including wheeled or track type tractors. The scraper  12 , which may generally include a frame  18  having an axle assembly  20  about which a scraper bowl  22  may pivot, may also be operated in a variety of configurations, including, for example, a push-pull configuration, as is well known in the art. 
     Scraper bowl  22  may define a cut opening  24 , at a front portion  26  of the scraper bowl  22 , with a cutting edge, such as a scraper blade  28 , positioned adjacent the cut opening  24 . During an exemplary operation, an apron  30  may be pivoted upward, to a raised position, to open, or unblock, the cut opening  24 , and also to increase the capacity of the scraper bowl  22 . The scraper bowl  22  may be pivoted downward about the axle assembly  20 , such as by using one or more scraper bowl actuators or cylinders  32 , to engage the scraper blade  28  with material  34 , such as, for example, soil. Such material  34  may be collected within the scraper bowl  22  as the tractor  14  and scraper  12  are maneuvered over the material  34 . When the scraper bowl  22  is loaded to some desired capacity, the scraper blade  28  may be pivoted upward so that the cutting edge is out of contact with the material  34 , and the machine  10  may be transported to a location where the material  34  is to be deposited. In addition, the apron  30  may be pivoted downward, to a lowered position, to close, or block, the cut opening  24  to prevent loss of the material  34  during transport. Although a simplified embodiment is described, it should be appreciated that scraper  12  may include additional components or features, such as, for example, an auger attachment, elevator mechanism, or ejector. 
     The tractor  14  may provide the sole means for propulsion and, in such arrangements, the tractor  14  and scraper  12  may include a single drive axle, such as, for example, a drive axle of a front axle assembly  36 . The front axle assembly  36  may be coupled with a frame  38 , or front frame, of the tractor  14 , which may support a front engine compartment  40 . An engine, such as an internal combustion engine, or other power source may be housed within the front engine compartment  40  and may provide power to front wheels  40  of the front axle assembly  36 . According to some embodiments, the scraper  12  may also include propulsion means, such as an internal combustion engine or other power source disposed within a rear engine compartment  44 , for driving rear wheels  46  of axle assembly  20 , also referenced herein as a rear axle assembly. The rear axle assembly  20 , disposed at a rear portion  48  of the scraper bowl  22 , may thus, according to such tandem powered arrangements, provide its own power, or traction. 
     Either or both of the engines, such as internal combustion engines, of the front engine compartment  40  and the rear engine compartment  44  may provide power to a hydraulic system of the scraper  12 . Specifically, an internal combustion engine of the machine  10  may power a hydraulic pump, which may provide a flow of hydraulic fluid to control one or more hydraulic devices of the machine  10 . For example, such a hydraulic pump may supply a flow of high-pressure hydraulic fluid to one or more hydraulic actuators, such as scraper bowl cylinders  32 , to the control movement of the scraper bowl  22 . Hydraulic systems are known and only peripherally within the scope of the present disclosure. Therefore, such hydraulic control will not be discussed herein in greater detail. 
     An operator control station  50  may be supported on the front frame  38 , and may include known devices, such as, for example, a seat assembly  52  and a steering device  54  that facilitate operator control of the tractor  14  and/or scraper  12 . The operator control station  50  may include various other devices, including, but not limited to, one or more machine operation controllers  56 . For example, one or more machine operation controllers  56  may be provided for selecting or controlling an engine speed of an internal combustion engine provided within either or both of engine compartments  40  and  44 . Further, one or more machine operation controllers  56  may be provided for controlling operation of the scraper  12 , such as by controlling movement of the scraper bowl actuators or cylinders  32 . Additional controls and devices, as should be appreciated, may also be provided within the operator control station  50  for controlling various operational aspects of the tractor  14  and/or scraper  12 . Such control, as referenced herein, may include either of mechanical or electronic control means, or a combination thereof. 
     Turning now to  FIG. 2 , an exemplary apron assembly of scraper  12  is shown generally at  60 . The apron assembly  60  may generally include the apron  30 , of  FIG. 1 , and a hydraulic actuator assembly, shown generally at  62 . The apron  30  may include an apron body  64 , which may have a curved or arcuate shape, extending between a first apron side  66  and a second apron side  68 . The first apron side  66  may be pivotably attached to a first bowl side  70  of the scraper bowl  22 , while the second apron side  68  may be pivotably attached to a second bowl side  72  of the scraper bowl  22 . For example, the second apron side  68  may be pivotably attached to the second bowl side  72  at a pivotable attachment point  74 . It should be appreciated that any attachments allowing movement of the apron  30  between raised and lowered positions, relative to the scraper bowl  22 , are contemplated for attaching apron  30  to the scraper  12 . 
     As shown, a portion of the apron  30  may include a gear surface, such as an arcuate gear surface matching the contour of the apron body  64 . Specifically, according to the exemplary embodiment, a first vertically aligned arcuate gear surface  76  and a second vertically aligned arcuate gear surface  78  may be positioned on an external side  80  of the apron  30 . The first vertically aligned arcuate gear surface  76  may be positioned at, or near, the first apron side  66 , while the second vertically aligned arcuate gear surface  78  may be positioned at, or near, the second apron side  68 . Although specific embodiments are shown, it should be appreciated that one or more arcuate gear surfaces may be provided on any portion of the apron  30 , such that a drive gear of the hydraulic actuator assembly  62  is positioned to engage the one or more arcuate gear surfaces of the apron  30 . The hydraulic actuator assembly  62 , according to the exemplary embodiment, may be supported on a support brace  82 , which may be perpendicular to and extend between the first bowl side  70  and the second bowl side  72 . 
     The hydraulic actuator assembly  62  may generally include a linear hydraulic actuator  84  configured to actuate one or more drive gears, which are in mesh with the first vertically aligned arcuate gear surface  76  and the second vertically aligned arcuate gear surface  78 . For example, the linear hydraulic actuator  84  may be configured to rotate a drive shaft  86 . The drive shaft  86 , according to one embodiment, may support a first drive gear  88 , which is rotatably coupled, or in mesh, with the first vertically aligned arcuate gear surface  76 , and a second drive gear  90 , which is rotatably coupled, or in mesh, with the second vertically aligned arcuate gear surface  78 . Although rotary motion is described, it should be appreciated that the linear hydraulic actuator  84  may be configured to move a flat drive surface, such as a rack, in a linear direction to engage first and second vertically aligned arcuate gear surfaces  76  and  78 . Such a drive surface, as should be appreciated, may also have a relatively vertical orientation. 
     The linear hydraulic actuator  84 , which may be actuated using the hydraulic system described above, may be substantially parallel with the drive shaft  86 , as shown, and may include a cylinder end  92  and a rod end  94 . The rod end  94  may be rotatably coupled with a drive block  96  mounted on the drive shaft  86 . The drive block  96 , which, according to the exemplary embodiment, may be positioned along the drive shaft  86  between the first drive gear  88  and the second drive gear  90 , may be configured to translate linear motion of the linear hydraulic actuator  84  into rotary motion of the drive shaft  86 . As shown, the linear hydraulic actuator  84  and the drive shaft  86  may be substantially perpendicular to parallel planes defined by the first apron side  66  and the second apron side  68 . Although specific orientations are described, it should be appreciated that the components of the hydraulic actuator assembly  62  may be positioned according to alternative arrangements and still provide the benefits described herein. 
     The hydraulic actuator assembly  62  may be configured to raise the apron  30  to a raised, or open, position, as shown in  FIG. 2 . Specifically, the linear hydraulic actuator  84  may be extended, using known hydraulic or other fluid means, such that the rod end  94  exerts a linear force on the drive block  96 . The drive block  96  translates the linear force or motion into rotary motion, which is described below, causing rotation of the drive shaft  86 . As the drive shaft  86  rotates, the first drive gear  88  and second drive gear  90 , supported on the drive shaft  86 , also rotate. Such rotation, in a first direction, causes the first drive gear  88  to engage the first vertically aligned arcuate gear surface  76 , and the second drive gear  90  to engage the second vertically aligned arcuate gear surface  78 , thus driving the apron  30  upward. When the linear hydraulic actuator  84  is retracted, using known hydraulic or other fluid means, the drive block  96  causes rotation of the drive shaft  86  in a second, or opposite, direction. Such opposite rotation causes the drive gears  88  and  90  to engage vertically aligned arcuate gear surfaces  76  and  78 , respectively, to drive the apron downward, to a closed position shown in  FIG. 3 . 
     As shown in both  FIG. 2  and  FIG. 3 , the scraper bowl  22  may include shields to protect the teeth of the gear surfaces, in at least one position of the apron  30 . Specifically, the scraper bowl  22  may include a first arcuate shield  100  that extends from the first bowl side  70  and is aligned with the first vertically aligned arcuate gear surface  76  in the closed position of the apron  30 . The second bowl side  72  may include a second arcuate shield  102  that extends from the second bowl side  72  and is aligned with the second vertically aligned arcuate gear surface  78  in the closed apron position. The first arcuate shield  100  and the second arcuate shield  102 , and/or additional shields, may be integral with any portion of the scraper bowl  22  or, alternatively, the apron assembly  60 , or may comprise separate components that are fixedly attached to the scraper bowl  22  or apron  30  using any known attachment means. In addition, the first and second arcuate shields  100  and  102  may match the contour of the apron body  64 , and thus first and second vertically aligned arcuate gear surfaces  76  and  78 , as shown. 
     Although two drive gears  88  and  90  and two gear surfaces  76  and  78  are shown, it should be appreciated that any number and/or type of drive gear surface, driven by the linear hydraulic actuator  84 , may be configured to drive any number and/or type of gear surfaces of the apron  30 . For example, as shown in  FIG. 4 , the apron  30  may include a single vertically aligned arcuate gear surface  110  positioned on the external side  80  of the apron  30 . Specifically, for example, the single vertically aligned arcuate gear surface  110  may be positioned at a central portion  112  of the external side  80  of the apron body  64 . According to this exemplary embodiment, the drive shaft  86  may include a single drive gear  114  rotatably coupled, or in mesh, with the single vertically aligned arcuate gear surface  110 . According to this, and other embodiments, the gear surfaces, and corresponding drive gears, may be positioned such that the linear hydraulic actuator  84  has sufficient space to fully extend and retract, as necessary. 
     Turning now to  FIG. 5 , the portions of the hydraulic actuator assembly  62  are shown in greater detail. Specifically, the drive block  96  may include at least one projection, such as a first inwardly extending projection  120  and a second inwardly extending projection  122 , positioned within a helical groove  124  of the drive shaft  86 . When the linear hydraulic actuator  84  is extended, the rod end  94  exerts a linear force on the drive block  96 . As the drive block  96  moves, in a linear direction, the first and second inwardly extending projections  120  and  122  engage the helical groove  124 , thus causing rotation of the drive shaft  86  in a first direction. As the rod end  94  of the linear hydraulic actuator  84  is retracted, the drive block  96  is moved in an opposite direction, causing first and second inwardly extending projections  120  and  122  to engage the helical groove  124  and rotate drive shaft  86  in a second, or opposite, direction. 
     It should be appreciated that the apron  30  and hydraulic actuator assembly  62 , as described herein, may provide a means for adjusting a position of the apron  30  relative to the scraper bowl  22 . Such adjustments may be made electronically and, further, may be made in response to a position of the front portion  26  of the scraper bowl  22  and/or a weight of material  34  within the scraper bowl  22 . For example, it may be desirable to raise the apron  30  when the front portion  26  and, thus, scraper blade  28  is pivoted downward to engage the material  34 . It may also be desirable to lower the apron  30  when the front portion  26  of the scraper bowl  22  is pivoted upward, such as when the scraper bowl  22  has reached a desired capacity. Alternatively, or additionally, such adjustments may be made manually, such as by actuating one or more of the machine operation controllers  56 . Additional adjustments, as should be appreciated, may be made, as desired, throughout operation of the scraper  12 . 
     INDUSTRIAL APPLICABILITY 
     The present disclosure finds potential application in any machine, such as a tractor scraper or a towed scraper, which utilizes a bowl, such as a scraper bowl. Further, the disclosure may be specifically applicable to scrapers having a cutting edge located adjacent a cut opening of the bowl, and an apron that may be raised or lowered to effectively open or close the cut opening. Yet further, the present disclosure may be applicable to aprons, or apron assemblies, that require smooth operation and increased position resolution. Such machines may include, but are not limited to, single engine scrapers, tandem powered scrapers, scrapers operating in a push-pull configuration, and other machines known in the art that utilize a bowl and apron for collecting material. 
     Referring generally to  FIGS. 1-5 , a machine  10 , such as a scraper  12 , may be pulled by a tractor  14  and may generally include a frame  18  and a rear axle assembly  20 , about which a scraper bowl  22  may pivot. The scraper bowl  22  may define a cut opening  24 , at a front portion  26  of the scraper bowl  22 , with a cutting edge, such as a scraper blade  28 , positioned adjacent the cut opening  24 . During a typical operation, or duty cycle, an apron  30  of the scraper  12  may be pivoted upward, to a raised position, to open, or unblock, the cut opening  24  of the bowl  22 , and also to increase the capacity of the bowl  22 . The scraper  12  may be pulled forward, at a material capturing location, while the cutting edge  28  of the bowl  22  is pivoted downward to cut through the material  34 . When the bowl  22  is loaded to some desired capacity, the cutting edge  28  of the bowl  22  may be pivoted upward so that the cutting edge  28  is out of contact with the material  34 , and the machine  10  may be transported to a location where the soil  34  is to be deposited. In addition, the apron  30  may be pivoted downward, to a lowered position, to close, or block, the cut opening  24  to prevent loss of the material  34  during transport. After the material  34  is deposited, the scraper  12  may be returned to the material capturing location, and the duty cycle may be repeated. 
     Utilizing the apron  30  and hydraulic actuator assembly  62 , as described herein, may provide an improved means for adjusting a position of the apron  30  relative to the scraper bowl  22 . Specifically, a linear hydraulic actuator  84  may be extended, using automatic or manual actuation means, such that a rod end  94  of the linear hydraulic actuator  84  exerts a linear force on a drive block  96 . The drive block  96  translates the linear motion into rotary motion, by engaging inwardly extending projections  120  and  122  with a helical groove  124  of a drive shaft  86 , causing rotation of the drive shaft  86 . As the drive shaft  86  rotates, a first drive gear  88  and a second drive gear  90 , supported on the drive shaft  86 , also rotate. Such rotation, in a first direction, causes the first drive gear  88  to engage a first vertically aligned arcuate gear surface  76  of the apron  30 , and the second drive gear  90  to engage a second vertically aligned arcuate gear surface  78  of the apron  30 , thus driving the apron  30  upward. 
     Similarly, when the linear hydraulic actuator  84  is retracted, using automatic or manual actuation means, the drive block  96  causes rotation of the drive shaft  86  in a second, or opposite, direction. Such opposite rotation causes the drive gears  88  and  90  to engage vertically aligned arcuate gear surfaces  76  and  78 , respectively, to drive the apron downward, to a closed position. Such an actuation means, as described herein, may provide improved actuation of apron  30 . Specifically, the hydraulic actuator assembly  62  may provide smooth operation and increased position resolution of the apron  30 , relative to the scraper bowl  22 . In addition, the components of the hydraulic actuator assembly  62  may provide an actuation means that satisfies strict spatial constraints. Such a hydraulic actuator assembly  62  may have a variety of uses, in addition to apron actuation, especially in machines that are already equipped with hydraulic systems and have strict spatial requirements for actuation mechanisms. 
     It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims.