Patent Application
20220112670
The present invention relates generally to the construction industry and more specifically to the road building industry. In particular, the present invention is a depth guide to be used with a road paving machine to allow the operator of the road paving machine a simple means for visually assessing whether the pavement layer being created by the road paving machine is of the proper thickness.
A road paving machine typically includes a tractor component and a movable screed component. The tractor component tows the screed behind it during operation. As the road paving machine moves along the roadbed, it deposits road paving material, typically asphalt, concrete, loose aggregates, and the like, onto the roadbed. The screed passes over the road paving material and flattens it into a pavement layer of desired thickness. Because road paving material is expensive, and because so much of it is used when paving a roadway, even small deviations from the specified thickness can result in significant cost overruns, or conversely, insufficient pavement durability if too little is used.
While the screed is initially set to the proper height, as the road paving machine moves over the roadbed the initial setting may no longer be correct. Variations in the roadbed, such as dips and bulges, can cause the height of the screed over the roadbed to vary, such that the layer of pavement formed by the screed is of the wrong thickness. If the height of the screed becomes too low for the condition of the roadbed, the pavement layer will be too thin and subject to failure. If the height of the screed becomes too high for the condition of the roadbed, the pavement layer will be too thick, thereby wasting road paving material and increasing costs. An experienced operator may be able to visually determine whether the height of the screed is properly set for the variable condition of the roadbed, and can then dynamically reset the height of the screed if required to set the correct thickness of the pavement layer being laid down. However, this is not an easy skill to acquire, and many operators, especially novices, are incapable of properly assessing the height of the pavement layer being created by the screed.
Because of this, there are a multitude of devices employed in the industry to detect the thickness of the pavement layer created by the screed. Most of these are electronic devices which use some combination of transmitters of sonic waves, such as ultrasound waves, or optical waves, such as lasers, together with sensors adapted to receive those waves and processors to convert the data into distance measurements, to determine the thickness of the pavement layer. While these devices work, they are complicated and very expensive and are not often found on smaller road paving machines.
What is thus needed is an inexpensive, simple device that allows the operator of a road paving machine to easily determine whether the pavement layer created by the screed is of the appropriate thickness so that adjustment of the screed can be made if necessary.
It is therefore an object of the present invention to provide a pavement depth guide for use on a road paving machine that can provide a visual indicator of the thickness of the pavement layer created by the screed to the operator of the road paving machine.
It is yet a further object of the present invention to provide a pavement depth guide for use on a road paving machine that is inexpensive and easy to use.
It is yet a further object of the present invention to provide a pavement depth guide for use on a road paving machine which is simple in design.
It is yet a further object of the present invention to provide a pavement depth guide for use on a road paving machine that does not require electronic components.
It is yet a further object of the present invention to provide a pavement depth guide for use on a road paving machine which may be used on any design of a road paving machine employing a movable screed.
Other objects of the present invention will be readily apparent from the description that follows.
In one aspect, the present invention is a mechanical device that the operator of a road paving machine visually perceives during operation of the road paving machine, whereby the perceived proximity of the device to the roadbed provides the operator with information regarding the thickness of the road paving material being deposited onto the roadbed and formed into a pavement layer by the screed. The device comprises an attachment component which attaches the device to the screed of the road paving machine, and a depth indicator which extends downward from the attachment component towards the roadbed. In one embodiment, the device further comprises a weighted distal indicator, which is suspended from the bottom of the depth indicator and which facilitates the operator viewing the proximity of the device to the roadbed. In another embodiment the device further comprises an extension arm, which holds the depth indicator away from the attachment component to better facilitate the operator viewing the proximity of the device to the roadbed. In yet another embodiment, the device further comprises a depth control gauge, which allows for initial adjustment of the overall length of the depth indicator, to correspond with the desired thickness of the pavement layer.
Additional features and advantages of the invention will be set forth in the description which follows, and will be apparent from the description, or may be learned by practice of the invention. The foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention
The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of the specification. They illustrate various embodiments of the invention and, together with the description, serve to explain the principles of the invention.
The depth guide 1 of the present invention is intended to be used with a road paving machine 10 having a movable screed 12 attached thereto. The road paving machine 10 is capable of depositing road paving material 20 onto a roadbed 30. The screed 12 is adjustable in height to control the thickness of the pavement layer formed from the road paving material 20 deposited onto the roadbed 30. See
The depth guide 1 of the present invention comprises an attachment component 100 and a depth indicator 200. See
The depth indicator 200 is elongate and has a length, a proximate end 210, and a distal end 212. The depth indicator 200 is attached to the screed 12 by the attachment component 100. The depth indicator 200 extends in a downward direction from the attachment component 100 towards the roadbed. It is attached to the attachment component 100 at its proximate end 210.
The length of the depth indicator 200 is such that when the screed 12 is positioned at a height for forming a pavement layer having a desired thickness, the distal end 212 of the depth indicator 200 hangs just over the unpaved roadbed 30. As such, the distal end 212 of the depth indicator 200 is visually perceived by the operator of the road paving machine 10 during operation of the road paving machine 10. The proximity of the distal end 212 of the depth indicator 200 to the roadbed 30 provides the operator with information regarding the thickness of the road paving material 20 being deposited onto the roadbed 30 and formed by the screed 12 into a pavement layer. The distal end 212 of the depth indicator 200 laying on the roadbed 30 indicates the pavement layer is too thin, and the distal end 212 of the depth indicator 200 dangling too far above the roadbed 30 indicates the pavement layer is too thick.
In the preferred embodiment, the depth indicator 200 is flexible. It may be formed of a length of metal cable, or from a nylon cord, or from rope, or any other elongate flexible material. In the most preferred embodiment the depth indicator 200 is a length of chain. Chain is preferred for its durability and weight, allowing it to readily hang in a downward direction. In an alternate embodiment, the depth indicator 200 may be inflexible, such as a metal rod. In such cases the depth indicator 200 is attached at its proximate end 210 by a pivot or hinge, so that if the pavement layer being formed by the screed 12 is too thin the distal end 212 of the depth indicator 200 will lay along the roadbed 30 at an angle.
In one embodiment of the present invention, the depth guide 1 further comprises a distal indicator 300. See
In yet another embodiment of the present invention, the depth guide 1 further comprises an extension arm 400. See
While the extension arm 400 of the depth guide 1 may extend outward at a fixed angle to the screed 12, such as substantially perpendicular to the screed 12, in the preferred embodiment the extension arm 400 is pivotally attached to the attachment component 100. The pivotal attachment allows the distal end 412 of the extension arm 400 to swing both away from and towards the screed 12. This allows the depth guide 1 to be placed flush against the screed 12 when not being used. In the preferred embodiment the distal end 412 of the extension arm 400 moves in a substantially horizontal plane. In alternative embodiments, the extension arm 400 moves in a substantially vertical place. The pivotal attachment may be a hinge or a ball and socket joint or any other arrangement known in the art to allow the extension arm 400 to pivot in relation to the screed 12. In another embodiment, the pivotal attachment is lockable, so that when the extension arm 400 is placed flush against the screed 12 it remains in place, and when it is extended away from the screed 12 it remains in place. Any known locking mechanism known in the art is contemplated. In an alternate embodiment the extension arm 400 may be comprised of two or more sub-arms, with the sub-arms pivotally connected to each other. As the sub-arms are unfolded, the extension arm 400 is extended away from the screed 12.
In yet another embodiment of the present invention, the depth guide 1 further comprises a depth control gauge 500. The depth control gauge 500 is used to set the overall vertical length of the depth guide 1 when the depth guide 1 is fixedly attached to the screed 12. The depth control gauge 500 is elongate and has a proximate end 510 and a distal end 512. It has an adjustable length and is oriented substantially vertically. The depth control gauge 500 is interposed between the distal end 412 of the extension arm 400 and the proximate end 210 of the depth indicator 200, with the proximate end 510 of the depth control gauge 500 being attached to the distal end 412 of the extension arm 400 and with the proximate end 210 of the depth indicator 200 being attached to the distal end 512 of the depth control gauge 500. See
The depth control gauge 500 has associated therewith a first length and a second length, with the second length being longer than the first length. It has a means for adjusting its overall length to the first length or to the second length, and to any intermediate length between the first and second lengths. In selecting the appropriate length, the depth control gauge 500 sets the overall vertical length of the depth guide 1. The depth control gauge 500 further has a means for fixing its length at the length to which it is adjusted, so that it remains at the selected length during use. In practice, first the screed 12 is adjusted to its desired height above the roadbed 30, then the length of the depth control gauge 500 is adjusted to set the position of the distal end 212 of the depth indicator 200 (or the bottom of the distal indicator 300) to just above the roadbed, then that desired length is fixed.
In the preferred embodiment, the depth control gauge 500 has markings 550 on it, either in inches or centimeters, to assist with setting the length of the depth control gauge 500. When equipped with such markings 550, the depth guide 1 must be attached to the screed 12 at a predefined height from the roadbed 30, so that the markings correlate with the thickness of the pavement layer.
In one embodiment of the depth control gauge 500, it is comprised of an inner shaft 520 and an outer sleeve 530. The inner shaft 520 is inserted into the outer sleeve 530 and is capable of moving at least partially within the outer sleeve 530, such that when a greater portion of the inner shaft 520 is exposed exterior to the outer sleeve 530 the overall length of the depth control gauge 500 is increased, and when a smaller portion of the inner shaft 520 is exposed exterior to the outer sleeve 530 the overall length of the depth control gauge 500 is decreased. See
In an alternative embodiment of the depth guide 1, the attachment component 100 is removably attached to the screed 12. This can be achieved by securing a bracket to the side of the screed 12, with several different attachment points arranged vertically on the bracket, and the attachment component 100 being placed onto whichever attachment point corresponds to the desired thickness of the pavement layer. In another embodiment, the attachment component 100 is removably attached to the screed 12 by use of one or more magnets 130. See
Once the depth control gauge 500 is properly set (or the magnet 130 of the attachment component 100 is properly positioned), the operator of the road paving machine 10 begins depositing road paving material 20 onto the roadbed 30. See
Components, component sizes, and materials listed above are preferable, but artisans will recognize that alternate components and materials could be selected without altering the scope of the invention.
While the foregoing written description of the invention enables one of ordinary skill to make and use what is presently considered to be the best mode thereof, those of ordinary skill in the art will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should, therefore, not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.
