1. Field of the Invention
The invention relates to the field of pavement/roadway construction/maintenance equipment and more particularly to an attachment for skid steer tractors configured to efficiently and economically remove pavement markings from paved surfaces.
2. Description of the Related Art
Paved surfaces, such as parking areas and roadways, are frequently provided with various patterns of markings. These markings can delineate parking spaces, travel lanes, pedestrian crosswalks, no passing zones, and the like. The markings are typically applied directly on the upper surface of the pavement and are typically formed with extremely durable and rugged paints which are designed to withstand the high wear of vehicle traffic as well as constant exposure to the elements, including temperature cycling, sunlight, and rainfall. The pavement markings are thus relatively durable, however, it is frequently desirable that the markings be removed, for example, to redesignate indicated parking spaces or to change the nature of lanes/traffic designations.
Due to the extremely durable nature of the paint marking material, as well as to provide a freshened and cleaned surface for subsequent reapplication of pavement markings, the markings are typically removed in an abrasive manner. This is typically performed by an apparatus which performs a vigorous scraping or scouring operation on the upper surface of the pavement to remove both the pavement markings as well as an upper portion of the underlying pavement. This serves both to substantially remove the pavement marking, a portion of which may have seeped into cracks or voids into the pavement surface, as well as to planarize and provide a clean roughened pavement surface which is more suitable for a subsequent application of new pavement markings.
Because of the strength and hardness of pavement material and the relatively large areas from which pavement marking is frequently removed, the process is typically performed with relatively heavy and powerful machinery to drive the abrasive cutters used to remove the payment markings. The machinery can be generally categorized into two groupings, relatively small man-propelled machines and relatively larger self-propelled machines. The smaller man-propelled machines have the advantage of lower cost and generally greater maneuverability, enabling more precise removal of pavement markings and removal in areas in which adequate clearance for larger self-propelled machines is lacking. A drawback to the man-propelled machines is that by being smaller, their rate of removal is typically lower than the larger self-propelled machines. In addition, the man-propelled machines are also typically more susceptible to operator error, including inconsistent removal of the pavement markings and/or varying removal depth resulting in a less planarized surface. The man-propelled machines also more directly expose the operator to potential hazards, such as moving traffic.
The larger self-propelled machines have the advantage of generally more rapid removal processing, including frequently both a wider removal swath and a more rapid linear rate of removal. The larger self-propelled machines also frequently offer a more consistent removal of the pavement markings and upper surface of the pavement, however, this is also highly dependent on the skill and attention of the operator. Drawbacks to the larger self-propelled machines are generally a much greater expense, both for initial purchase and ongoing utilization of the larger, more complicated machines. A further drawback is that the larger self-propelled machines are frequently of single purpose in design and construction, i.e. limited to the sole use of the machine for removal of pavement markings. Thus, a contractor or municipality performing work which includes removal of pavement marking may elect to incur the significant expense of purchase of a dedicated pavement marking machine, however, the actual use of the machine may be intermittent leading to the circumstance of an expensive piece of machinery frequently sitting unused and idle. It will be appreciated that this can be an inefficient use of limited funds and resources.
A further limitation to the larger self-propelled machines but one which is also frequently experienced with smaller man-propelled machines is that they are frequently ill-suited to readily accommodating uneven pavement surfaces. For example, transitions between a relatively flat and a cambered roadway section can result in an alteration of the engineered contour of the roadway crowning/camber and/or inconsistent removal of pavement marking and upper surfaces of the roadway.
Thus, it will be appreciated that there is a need for an apparatus for removing pavement markings which offers flexibility of use in different pavement configurations, is cost effective and easy to use, is more tolerant of lack of skill or inattention on the part of an operator, is economical in use, and offers more efficient utilization of limited construction/road rehabilitation resources.
The invention includes an attachment which can be removably attachable to a motor vehicle, such as skid steer tractor. The attachment includes an abrasive cutter which is driven to remove pavement markings as well as an upper portion of the pavement surface, depending upon the particular application. In certain embodiments, the attachment receives operating power for the cutter from the vehicle, such as hydraulic power to drive a hydraulic motor of the attachment. Moving parts of the attachment as well as an operator can be substantially enclosed to provide protection against workplace hazards as well as dust and debris which is generated during use of the system. A debris suppression system can be included to suppress dust and debris generated during use. The attachment is simple and lightweight in construction and allows economical expansion of the capability of existing motor vehicles. The attachment can be arranged on the vehicle to facilitate removing pavement markings around obstacles such as curbs.
One embodiment includes an attachment for tractors comprising an attachment frame which is removably attachable to a tractor providing both motive power for movement of the tractor and operative power for ancillary equipment, a drive motor attached to the frame and interconnected to the tractor such that the drive motor receives operative power from the tractor, and a cutter head attached to the frame, operably interconnected to the drive motor, and arranged such that the motor can drive the cutter head so as to remove an upper portion of a pavement surface. Another embodiment is a pavement marking removal system comprising a self-propelled tractor and a marking removal attachment removably attached to the tractor and receiving operating power therefrom. These and other objects and advantages of the invention will be more apparent from the following description taken in conjunction with the accompanying drawings.
Reference will now be made to the drawings wherein like reference designators refer to like parts throughout.
The attachment 100 comprises a frame assembly 30 configured to be attached to the motor vehicle 102 and in certain embodiments the attachment of the frame assembly 30 to the motor vehicle 102 comprises a removable attachment. This provides the advantage to the user that the pavement marking removal attachment 100 may be procured and attached to the motor vehicle 102 as needed, however, when the job does not require the use of the pavement marking removal attachment 100, said attachment 100 can be readily removed and the motor vehicle 102 can be utilized for other purposes. This provides the advantage to the users that the motor vehicle 102 can be utilized in a wide variety of different applications, including a pavement marking removal process. This is a particular advantage in certain embodiments as construction companies and municipalities will frequently already own and use a motor vehicle 102, such as a skid steer tractor, for a variety of purposes, and simply by procuring and utilizing the attachment 100, the user obtains the additional capability of efficiently removing pavement markings without incurring the capital expense of a dedicated pavement marking removal machine.
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The head assembly 101 also comprises a motor pulley 2 and a drive pulley 3 which are coupled by a drive belt 23. A belt tensioner 8 also engages with the drive belt 23 to maintain a desired tension to provide good frictional contact between the motor 2 and drive 3 pulleys and the drive belt 23. Together, these components define a drive assembly 4 which is interconnected to a cutter assembly 6. The drive assembly 4 provides the advantage that varying sizes of the motor pulley 2 and drive pulley 3 can provide an upward or downward gearing to provide differential rotational speeds between the drive motor 1 and the cutter assembly 6. The drive assembly 4 also provides a limited degree of slippage between the motor pulley 2 and drive pulley 3 such that, for example, if during use the cutter assembly 6 experiences a sharp deceleration, this deceleration can induce a degree of slippage of the drive belt 23 to reduce possible damage to the attachment 100.
The head assembly 101 also comprises a chassis 5 which provides structural support and mounting structure for other components of the head assembly 101. The head assembly 101 also comprises a hood 7 which can be raised to provide access to working components of the head assembly 101 as well as lowered to provide an enclosure for the working and moving parts of the head assembly 101. The hood 7 provides this enclosure feature which provides the advantages both of shielding and protecting operators and bystanders from exposure to the moving and working parts of the head assembly 101 as well as shielding adjacent personnel from dust and debris which may be generated during use of the attachment 100. Holddowns 20 are also provided to secure the hood 7 in the lowered or enclosed position. A flexible skirt 10 is also provided at a lower region of the chassis 5 which also serves to enclose the cutter assembly 6 to shield adjacent personnel both from moving parts of the head assembly 101 and from dust and debris generated during use of the attachment 100.
The head assembly 101 also comprises a forwardly disposed attachment support 11 which in one embodiment comprises a skid assembly. The attachment support 11 is configured to slide or roll in a generally low friction manner over a pavement surface as the motor vehicle 102 propels the pavement marking removal system 200. In one particular embodiment, the attachment support 11 comprises the skid assembly with two laterally opposed skid members 39a and 39b which are provided with a durable and low friction coefficient material which can readily slide over the pavement surface during use. The head assembly 101 rests on the attachment support 11 and the weight of the head assembly 101 is thereby borne by the skid members 39a and 39b. Thus, the skid members 39a and 39b are maintained in contact with the road surface by weight load and will raise or lower with changes in the road contour. Similar rises or drops in the road contour will induce corresponding pitch changes in the head assembly 101. Opposing rises and drops from side to side will induce corresponding self-adjusting torque to the head assembly 101 to induce rotation about the roll axis R to follow gross irregularities in the pavement surface.
The head assembly 101 also comprises a height adjustment assembly 200 including in this embodiment a threaded adjuster bolt 21, an adjuster washer 22, an adjuster nut 19, and an adjuster lock 18. In this embodiment, the adjuster assembly 200 threadably engages with the attachment support 11 in an adjustable manner such that the vertical spacing or height of the head assembly 101 with respect to the pavement surface can be adjusted. In one embodiment, loosening of the adjuster lock 18 allows the adjuster bolt 21 to rotate. Rotation of the adjuster bolt 21 as threadedly engaged with the attachment support 11 changes the axial engagement of the adjuster bolt 21 with the attachment support 11, thus varying the height or extension of the attachment support 11 with the rest of the head assembly 101 upwards or downwards, depending on the direction of rotation of the adjuster bolt 21. This provides the advantage of providing a varying cutting or removal depth such that the amount of material removed during a pass of the attachment 100 over the pavement surface can be adjusted to the requirements of specific applications. The adjuster lock 18 provides the advantage that once set to the desired removal depth, further adjustment of this removal depth is inhibited by the adjuster lock 18 fixing the adjuster bolt 21 in place. This decreases the likelihood that an unskilled or inattentive operator would misadjust the setting of the removal depth.
In one particular embodiment in which the drive motor 1 comprises a hydraulic motor, the head assembly 101 also comprises a hydraulic hose 12 which provides pressurized fluid, such as hydraulic fluid or water, to the drive motor I and returns the fluid to the motor vehicle 102. The head assembly 101 also comprises a hose adaptor 26, a hydraulic nipple 27, and a check valve 9 to interconnect the hydraulic hose 12 to the drive motor 1. The check valve 9 provides pressure relief should undesirably elevated pressures appear in the hydraulic line 12. Drive bushings 24 and motor bushing 25 are also provided to interconnect the cutter assembly 6 to the drive motor 1.
In this embodiment, the attachment 100 also comprises a dust suppression system including an inner dust suppression hose 16, an outer dust suppression hose 17, and a nozzle 28 which are interconnected together. In one embodiment, the nozzle 28 is attached to an underside of the chassis 5 adjacent a working or cutting area of the cutter assembly 6 and within the interior of the flexible skirt 10. In one embodiment, the dust suppression system comprises a water delivery and spray capability to apply a water spray to the working surface to suppress dust and debris which is generated during use of the system 200. In this embodiment, the nozzle 28 is arranged to direct a spray of water towards the working area of the cutter assembly 6 such that water sprays so as to dampen and suppress dust generated during cutting operations. In other embodiments, the dust suppression system comprises a vacuum system. In these embodiments, the nozzle 28 is similarly arranged adjacent a working or cutting area of the cutter assembly 6 and interconnected to the inner and outer hose 16, 17 which provide vacuum to draw away dust and debris which is generated during use of the system 200. In preferred embodiments, water supply and/or vacuum for the dust suppression system is provided by the motor vehicle 102 to simplify the construction of the attachment 100 as well as to reduce the costs thereof.
The head assembly 101 also comprises a motor plate 13 configured to support the drive motor 1 and drive assembly 4. The head assembly 101 also comprises one or more motor bolts 29 to secure the drive motor 1 to the motor plate 13. It will also be appreciated that in other embodiments, the height of the cutter assembly 6 from the pavement surface can be adjusted to provide the variable removal depth by adjusting the height of the drive motor and drive assembly 4 with respect to the chassis 5. Thus, in certain embodiments, the attachment of the drive motor 1 and drive assembly 4, such as via the motor plate 13 and motor bolts 29, is adjustable along a vertical extent such that the protrusion of the cutter assembly 6 can be varied along the vertical extent to adjust the removal depth.
In one embodiment, the chassis 5 of the head assembly 101 includes a threaded extension 51 extending generally rearwards from a rear face of the chassis 5. The head assembly 101 also comprises in this embodiment a pivot nut 14 sized and configured to threadedly engage with the threaded extension 51 and a pivot washer 15 interposed between the head assembly 101 and the frame assembly 30. The threaded extension 51 extends into a corresponding opening of the frame assembly 30 and is interconnected therewith via the pivot nut 14 and pivot washer 15. The pivot nut 14 is tightened sufficiently to secure the head assembly 101 to the frame 30, however loosely enough to allow rotation of the head assembly 101 with respect to the frame 30 under sufficient force. Thus, the head assembly 101 can rotate about the roll axis R as secured to the frame assembly 30 via the pivot nut 14 and pivot washer 15, for example due to imposed roll torques provided by contact of the skid members 39a and 39b with a varying road surface. This embodiment provides a particularly simple and robust construction which is durable and reliable in use.
The frame assembly 30 also comprises in this embodiment a pair of rearwardly disposed attachment supports 34 comprising caster wheels. In a similar manner to the forwardly disposed attachment supports 11, the rearwardly disposed attachment supports 34 also provide support for the attachment 100 and facilitate relatively low friction sliding or rolling of the attachment 100 over a pavement surface. It will be appreciated that in various embodiments the attachment supports 11, 34, can include skids, caster wheels, and/or track balls.
The cutter assembly 6 comprises a plurality of cutter wheels 62 which are rotatably connected to a mount 64 via a corresponding plurality of laterally extending wheel shafts 82. The cutter wheels 62 are secured to the wheel shafts 82 and mount 64 via a corresponding plurality of wheel fasteners 76, lock washers 78 and washers 80.
The cutter assembly 6 also comprises a hub connector 66 configured to be threadedly engaged with the second end of the drive shaft 44. The hub connector 66 is connected to the mount 64 via a plurality of spacers 84 and dampeners 68 via mounting fasteners 72 with corresponding washers 74. In one embodiment, the cutter wheels 62 comprise tungsten carbide tipped cutters and are arranged to the cutter assembly 6 so as to provide a cutting width of approximately 8 inches. The cutter wheels 62 can be replaced when worn and it will be appreciated that in other embodiments, a cutter assembly 6 can be arranged to provide greater or narrower cutting widths.
In embodiments wherein the drive motor 1 comprises a hydraulic motor, the drive motor 1 can operate with a relatively low hydraulic flow and in preferred embodiments, can readily operate with flow rates of approximately 10 to 15 gallons per minute. The combined weight of the attachment 100 in certain embodiments is approximately 500-550 lbs. which can be readily accommodated by conventional commonly available motor vehicles 102, such as conventional skids steer tractors. The system 200 can provide a linear cutting rate of approximately 50 ft. per minute depending upon the working conditions. The overall dimensions of the attachment 100 are approximately 60 inches in length, 46 inches in width, and 23 inches in height which again can be readily accommodated by conventional commonly available motor vehicles 102. Further advantages are that the operator is substantially completely enclosed within the motor vehicle 102 and is much less directly exposed to the hazards of traffic and other dangers which would be encountered with the man-propelled pavement marking removal machines.
In addition, in preferred embodiments, there are substantially no exposed moving parts. For example, the cutter assembly 6 and drive assembly 4 are enclosed which provides increased safety during use to the operator and any bystanders. The automatic belt tensioner 8 provides continuous automatic adjustment of the belt 23 tension and thus relieves the burden on an operator or owner of the attachment 100 to periodically adjust the belt 23. Further, the drive assembly 4 includes the drive belt 23 which can be readily replaced when worn with a relatively inexpensive item. The sealed bearings in the moving parts, such as the drive motor 1 and drive assembly 4 are sealed and pre-lubricated to reduce the requirements for periodic maintenance and cleaning. In certain embodiments, the drive motor 1 comprises a hydraulic motor which does not require maintenance such as oil changes, tune-ups, etc. and receives operating power from the motor vehicle 102 which simplifies the maintenance requirements for owners/users of the system 200 as well as reducing the costs. The attachment supports 11, 34, particularly when comprising casters or track balls allow the system 200 to readily sweep the attachment 100 from side to side which facilitates removal of relatively large areas of pavement marking.
Although the foregoing description of the preferred embodiment of the present invention has shown, described, and pointed out the fundamental novel features of the invention, it will be understood that various omissions, substitutions, and changes in the form of the detail of the apparatus as illustrated, as well as the uses thereof, may be made by those skilled in the art without departing from the spirit of the present invention.
This application claims the benefit of the U.S. Provisional Application Ser. No. 60/613,017 entitled “Pavement Marking Remover Attachment For Skid Steer Tractor” filed Sep. 23, 2004, which is incorporated in its entirety herein.
Number | Date | Country | |
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60613017 | Sep 2004 | US |