Abstract:
A steering mechanism for a milling attachment device provides steering capability without impeding cutting depth control. The steering mechanism has at least one wheel that is rotated by an actuating mechanism such as an extending cylinder, synchronized actuators, or the like. The steering mechanism may be integrated with depth control by using a parallelogrammic structure with pivot points to assist in the depth control or may operate independent of and without impeding depth control.

Description:
RELATED APPLICATION 
       [0001]    This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/565,278 that was filed on Nov. 30, 2011, for an invention titled STEERABLE SYSTEM FOR ASPHALT MILLING DEVICE, which is hereby incorporated herein by this reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to systems and methods for milling asphalt. More specifically, the present invention relates to attachable systems and methods that improve milling by providing steering capability while maintaining depth control for a milling device. 
         [0004]    2. The Relevant Technology 
         [0005]    Portable asphalt milling attachments historically comprise two principal features. They have a way to control the depth that the milling attachment device cuts. They also have a way to facilitate the changing of bits mounted to a cutting wheel of the milling attachment device. However, such devices are quite heavy and can prove very difficult to steer and keep on line, particularly when the host vehicle is small or has difficulty moving very heavy objects. 
         [0006]    The pending application Ser. No. 12/792,933, entitled “Asphalt Milling Attachment with Depth Control and Bit Access,” which has been published as United States Publication No. 2010/0308640 A1 and which is specifically incorporated by this reference, discloses that the front of the machine could use a skid foot to contact the ground to maintain depth or it could use a wheel. Also disclosed is that the skid foot could be solid or it could pivot to follow the ground, or that it could use a combination of both. However, steering capability for the skid plate or wheel is not provided. 
         [0007]    Accordingly, a need exists for a new system and method for providing steering capability for an asphalt milling attachment while maintaining depth control and bit access. Such systems and methods are disclosed herein. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available asphalt milling/trenching attachments. 
         [0009]    This disclosure provides steering capability that operates independent of or can be integrated with depth control and will not interfere with bit access. 
         [0010]    The front of the machine has one or more steerable wheels that are controlled hydraulically, electrically, pneumatically, or by using any other suitable drive. The wheel or wheels may be of any suitable type, including caster-type wheels, and may be raised or lowered to maintain desired depth control in the milling/trenching process. In certain embodiments, the steerable wheels are disposed forward of the milling assembly such that they will not impede bit access for repair and/or replacement. 
         [0011]    Asphalt milling devices are quite heavy and some are self-propelled. The self-propelled asphalt milling devices are steerable, but are extremely expensive and have limitations. Asphalt milling attachments can be attached to and maneuvered by a host vehicle, but heretofore the host vehicle provides the steering. Because asphalt milling attachments are quite heavy, smaller host vehicles or host vehicles that have difficulty moving very heavy objects have difficulty steering when a milling attachment is attached. The attachment embodiments disclosed herein facilitate maneuverability by providing a steering mechanism for the attachment. The asphalt milling attachments of the present disclosure could use a bucket slot in the rear of the asphalt milling attachment to allow a host vehicle to connect to it. Alternatively, other known quick-connects (JRB style, skid steer or balderson style) could be used. Host vehicles for the asphalt milling attachment could include back hoes, loaders, excavators, track hoes, skid steers and the like. However, without the steering capability provided in the present disclosure, steering the asphalt milling attachment or maintaining a desired line and milling depth can prove to be very difficult for an operator of the device, particularly if the host vehicle is a smaller vehicle. The present invention is much more versatile than known asphalt milling devices because it provides steering capability for the asphalt milling attachment that can be attached to and used by a broader range of host vehicles. In one embodiment, the wheel is a caster wheel that can be locked into a particular orientation (such as directly forward) or unlocked so that the operator can steer the device right or left. In some embodiments, the steering capability is independent of the depth control, and does not interfere with depth control. In other embodiments the steering is integrated with the depth control such as when the wheel is also connected to a framework that can be raised or lowered to assist in controlling the depth of the milling performed by the device. 
         [0012]    With the steerable wheel system in use, the intended use of the asphalt milling device could be to cut asphalt, concrete or any other road construction/parking lot material. The milling device could also be used for soil stabilization. It could be used for full depth reclamation of roads. These and other features will become more fully apparent from the following description, or may be learned by the practice of the steerable wheel system as set forth hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0013]    In order that the manner in which the above-recited and other features and advantages of the invention are obtained will be readily understood, a more particular description of exemplary embodiments of the invention, briefly described above, will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
           [0014]      FIG. 1  is an elevation view of an asphalt milling device with a steering mechanism and showing a host vehicle in outline to illustrate one exemplary method for connecting the host vehicle to the asphalt milling device; 
           [0015]      FIG. 2  is a perspective view of an exemplary asphalt milling device with a steering mechanism; 
           [0016]      FIG. 3  is a perspective frontal view of an asphalt milling device showing various components of an exemplary steering mechanism; 
           [0017]      FIG. 4  is a perspective right side view of the steering mechanism for the asphalt milling device; 
           [0018]      FIG. 5  is a perspective left side view of the steering mechanism for the asphalt milling device; 
           [0019]      FIG. 6  is a perspective view of an alternative two-wheel embodiment of a steering mechanism for an alternate asphalt milling device showing the wheels in a forward mode; and 
           [0020]      FIG. 7  is a perspective side view of the alternative two-wheel embodiment of the steering mechanism for the alternate asphalt milling device showing the wheels in a side mode. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Exemplary embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. It will be readily understood that the components of steerable asphalt milling devices, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the present disclosure, as represented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of exemplary embodiments of the invention. 
         [0022]    The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated. 
         [0023]    In this application, the phrases “connected to”, “coupled to”, and “in communication with” refer to any form of interaction between two or more entities, including mechanical, hydraulic, electrical, magnetic, electromagnetic, and pneumatic interactions. 
         [0024]    The phrases “attached to”, “secured to”, and “mounted to” refer to a form of mechanical coupling that restricts relative translation or rotation between the attached, secured, or mounted object, respectively. 
         [0025]    The term “pivoting” refers to items that rotate about an axis. A “pivoting engagement” is an engagement between two or more items in direct contact, with one or more of the items being capable of pivoting about an axis common to each of the items. 
         [0026]      FIG. 1  is an elevation side view of an embodiment of an asphalt milling device  10  with a steering mechanism  12  and is shown as attached to an exemplary host vehicle  50 . This embodiment shows that the asphalt milling device  10  is an attachment that is connected to a bucket-type of host vehicle  50  that can be used to drive and steer the device  10 . The host vehicle  50  has a bucket  52  that engages a bucket slot  13  on the asphalt milling device  10 . Alternatively, known quick-connects (JRB style, skid steer or balderson style) can be used to connect the host vehicle  50  to the asphalt milling device  10 . Because the asphalt milling device  10  has a steering mechanism, various types of host vehicles  50  can be used to connect to and steer the steerable asphalt milling device  10 , including back hoes, loaders, excavators, track hoes, skid steers and the like. 
         [0027]      FIG. 2  is a perspective view of an exemplary asphalt milling device  10  with the steering mechanism  12  ready for connection to the host vehicle  50 . The steering mechanism  12  comprises a wheel  14  pivotally mounted to a support bar  16  via a substantially vertically disposed pivot shaft  18 , a pair of cooperating, steering actuators  20 , a pair of stationary brackets  22 , a rotating bracket  24 , and a hydraulic drive (not shown). In  FIG. 2 , the wheel  14  is a caster-type wheel securely connected to the pivot shaft  18  so that when the pivot shaft  18  rotates, the wheel  14  also rotates. It should be understood that other types of wheels can be used, but the caster-type wheel  14 , as shown in  FIGS. 2 and 3 , is particularly suitable for the intended use. 
         [0028]    The pivot shaft  18  is carried in a shaft opening in the support bar  16  and extends above the support bar  16  so that the rotating bracket  24  can be attached to the pivot shaft  18 . The rotating bracket  24  comprises a collar  28  and laterally extending ears  30  (the reference numerals  28 ,  30  are not shown in  FIG. 2  so not to obscure other features of the device; however, collar  28  and ears  30  may be similar to what is shown in  FIG. 3 ). The collar  28  fits snug about the pivot shaft  18  and can be secured to the pivot shaft  18  by any suitable means, such as by screw, bolt, key, set screw, weld, or the like. Ears  30  provide a location for pivotally attaching the cooperating steering actuators  20 . Each of the stationary brackets  22  is secured to the support bar  16  and spaced to provide locations for pivotally attaching the cooperating steering actuators  20 . One end of each steering actuator  20  is pivotally attached to a stationary bracket  22  while the other end is pivotally attached to ears  30  of the rotating bracket  24 , so that distance between the two stationary brackets  22  is covered by the ears  30  and steering actuators  20 , with the ears  30  being disposed between the two steering actuators. In this manner, as one of the steering pistons  20  contracts, the other steering piston  20  extends, thereby causing the ears  30  to move to the right or left and rotating the pivot shaft  18  and wheel  14  accordingly. A hydraulic drive (not shown in  FIG. 2 ) is connected to the steering pistons  20  via hydraulic hoses and fittings  32  (not shown in  FIG. 2 ). By regulating the extension and contraction of the steering actuators  20  via the delivery of hydraulic fluid through the hoses and fittings  32 , the user can steer the wheel  14  in a desired direction. Although a hydraulic drive is disclosed, it should be understood that other types of drives may suitably rotate the pivot shaft  18 , thereby steering the wheel  14 . 
         [0029]      FIG. 3  is a perspective frontal view of an exemplary embodiment of an exemplary asphalt milling device  10 . The steering mechanism  12  comprises a wheel  14  pivotally mounted to a support bar  16  via a substantially vertically disposed pivot shaft  18 , a pair of cooperating, steering actuators  20 , a pair of stationary brackets  22 , a rotating bracket  24 , and a hydraulic drive (not shown). In  FIG. 3 , the wheel  14  is a caster-type wheel securely connected to the pivot shaft  18  so that when the pivot shaft  18  rotates, the wheel  14  also rotates. It should be understood that other types of wheels can be used, but the caster-type wheel  14  is particularly suitable for the intended use. 
         [0030]    The pivot shaft  18  is carried in a shaft opening in the support bar  16  and extends above the support bar  16  so that the rotating bracket  24  can be attached to the pivot shaft  18 . The rotating bracket  24  comprises a collar  28  and laterally extending ears  30 . The collar  28  fits snug about the pivot shaft  18  and can be secured to the pivot shaft  18  by any suitable means, such as by screw, bolt, key, set screw, weld, or the like. Ears  30  provide a location for pivotally attaching the cooperating steering actuators  20 . Each of the stationary brackets  22  is secured to the support bar  16  and spaced to provide locations for pivotally attaching the cooperating steering actuators  20 . One end of each steering actuator  20  is pivotally attached to a stationary bracket  22  while the other end is pivotally attached to ears  30  of the rotating bracket  24 , so that distance between the two stationary brackets  22  is covered by the ears  30  and steering actuators  20 , with the ears  30  being disposed between the two steering actuators. In this manner, as one of the steering actuators  20  contracts, the other steering actuator  20  extends, thereby causing the ears  30  to move to the right or left and rotating the pivot shaft  18  and wheel  14  accordingly. As shown in  FIG. 3 , the steering actuators  20  are hydraulic pistons. However, it is contemplated that the steering actuators  20  may be electrical, pneumatic, or may be powered by any other suitable drive without departing from the concepts of the invention contemplated. For clarity in the remaining description, the steering actuators  20  are hydraulic pistons, as shown. 
         [0031]    The hydraulic drive (not shown in  FIG. 3 ) is connected to the steering actuators  20  via hydraulic hoses and fittings  32 . By regulating the extension and contraction of the steering actuators  20  via the delivery of hydraulic fluid through the hoses and fittings  32 , the user can steer the wheel  14  in a desired direction. 
         [0032]      FIGS. 4 and 5  are perspective right side and left side views, respectively, of the steering mechanism  12 , showing a height-adjustment mechanism  34  for the steering mechanism  12  Because the asphalt milling device  10  can mill to various depths, the height of the wheel  14  of the steering mechanism  12  is also adjustable to assist in maintaining depth control. In some embodiments, the wheel  14  can be raised and lowered using a pivoting parallelogrammatic structure, generally designed as  36 , and comprising four pivot points  38   a ,  38   b ,  38   c , and  38   d . Between pivot points  38   a  and  38   c , a height-adjusting strut such as a height-adjusting hydraulic piston  40  is provided. By extending and contracting the length of the height-adjusting strut (e.g., a hydraulic piston  40 ), the configuration of the parallelogrammatic structure  36  will change and the support bar  16  and wheel  14  can be raised and lowered to achieve a desired milling depth or to lift the front of the asphalt milling device  10  to clear a zero milling depth. Although a hydraulic piston  40  is shown, it should be understood that any type of height-adjusting strut that effectively alters its operating length with respect to the parallelogrammatic structure  36  may be used. Also, it should be understood by those skilled in the art that the height-adjusting strut can be connected to the parallelogrammatic structure  36  between points on the structure other than pivot points  38   a  and  38   c , so long as the strut can still change the configuration of the structure  36  to raise and lower the support bar  16 . By way of example of struts other than a hydraulic piston  40 , the strut can be length-adjustable or telescoping linkage that is attached between adjacent sides of the parallelogrammatic structure  36 . 
         [0033]    As shown in both  FIGS. 4 and 5 , a support arm  41  is connected to the support bar  16  and a portion of the support arm  41  (designated as  43 ) forms one of the sides of the parallelogrammatic structure  36 . 
         [0034]      FIG. 4  also shows the hydraulic hoses and fittings  32  extending from the steering mechanism  12 . Similarly, the height-adjusting hydraulic piston  40  has hoses and fittings  42 . These hoses  32 ,  42  are connected to the hydraulic drive (not shown) which is controlled by control means known in the industry. However, it should be understood that more than one hydraulic drive (or any other type of suitable drive) may be used to drive the various driven components described herein. 
         [0035]      FIGS. 6 and 7  are illustrations of an alternative embodiment, using a two-wheel configuration on an asphalt milling device  10 , showing a different steering mechanism  12  and height control. With this alternative embodiment, each wheel  14  is mounted to an arm  26  that extends from the support bar  16 . The pivot shaft  18  is encased within a cylinder  44  on the end of the arm  26 . The direction of each wheel  14  can be controlled by independent synchronized actuator steering or can be locked, using a locking mechanism  45 , into a particular direction manually (see e.g., the array of pin holes  46  and the locking pin hole  48  into which a locking pin (not shown) can be inserted). Independent synchronized actuator steering can be controlled hydraulically (hydraulic fittings  32  are shown in  FIG. 6 ) to rotate the wheels  14  for steering. When a single, constant direction is desired, the locking mechanism  45  can be locked into a particular direction. Though the steering mechanism  12  differs from the single wheel embodiment described above, one skilled in the art can readily practice the two-wheeled embodiment based on the above disclosures and the figures shown. 
         [0036]    The alternative embodiment of a two-wheel configuration for the asphalt milling device  10  of  FIGS. 6 and 7  illustrates an embodiment where an outer frame  54  is rigid and is supported by the wheels  14  and an inner frame  56  that can hydraulically lift or lower the rotating cutting head  58  into place for milling at depths ranging from zero depth to full depth. The inner frame  56  is lifted/lowered so that the cutting head  58  is disposed in the desired cutting position by hydraulic struts  60  while the outer frame  54  maintains its disposition supported by the wheels  14  and the host vehicle  50 . 
         [0037]    Additionally, the arms  26  may pivot about their connections to the support arm  16  so that the wheels  14  can swing from a forward mode ( FIG. 6 ) to a side mode ( FIG. 7 ). When in the side mode, the cutter head  58  can advance much closer to a wall, an obstacle, a barrier, or the like, at the front of the asphalt milling device  10 , while maintaining steering capability. 
         [0038]    Although the exact configuration of the hydraulic drive together with the hoses and fittings, and the controls for regulating the hydraulic power have not specifically been shown, one skilled in the art, armed with the disclosure provided herein can configure the hydraulics to provide both steering and height-adjustment by locating needed controls in the host vehicle  50 . 
         [0039]    The present invention may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.