Fluid sprinkling – spraying – and diffusing – Processes
Reexamination Certificate
1999-07-14
2001-05-08
Scherbel, David A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Processes
C239S455000, C239S456000, C239S505000, C239S668000, C239S673000, C239S676000
Reexamination Certificate
active
06227454
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to devices and methods for marking road surfaces and, more particularly, to devices and methods for creating road markings of various patterns including markings having varying thicknesses across their widths for increased reflectivity.
2. Description of the Related Art
The surfaces of roads, highways, parking lots and the like (hereinafter “road surfaces”) are commonly marked with lines, stripes and other indicators (hereinafter “road markings”) for designating traffic and parking lanes, and for similar purposes. To improve the visibility of such road marking s during low-light and nighttime conditions, the markings are commonly formed using reflective materials, including small glass beads that are frequently deposited over the road markings shortly after the markings are applied to a road surface (and before the markings dry or cure)
To further increase the reflectance of road markings, it is known to form multiple steps or tiers in the markings, where adjacent tiers are connected by an inclined or sloping section. These tiered and sloping sections, referred to in the trade as “profiles,” constitute retroreflective surfaces that generally reflect light into the line of sight of oncoming traffic. Road markings of this type are commonly formed using a road marking device comprising a material hopper, a floor gate, a pair of side runners and a vertically oriented shutter. In use, the side runners are dragged along, and support the hopper above, the road surface. The floor gate is positioned adjacent to an outlet extending through a bottom side of the hopper and, in its closed position, covers the outlet and prevents marking material from flowing therethrough. When the floor gate is moved away from the outlet, marking material flows through the outlet and onto the road surface between the pair of side runners. The runners thus serve both to provide sliding support for the device as well as to provide side forms which limit lateral flow of the marking material and thereby define the side edges of the road marking. The tiers are formed in the road marking (i.e., the thickness of the road marking is intermittently varied along its length) by adjusting the height of the vertically oriented shutter, which is positioned between the side runners of the device and rearwardly of the hopper outlet. If the shutter is arranged, for example, such that its bottom edge is spaced an eighth of an inch from the road surface, the shutter will permit only one-eighth of an inch of marking material to pass thereunder, thus yielding a road marking having, at that location, a uniform thickness of approximately one-eighth of an inch. Changing the elevation of the shutter as the device is advanced along the road surface results in the inclined or sloped sections mentioned above.
Although suited for its intended purpose, the device described immediately above can produce road markings having only limited profile patterns (i.e., the aforementioned multi-tiered patterns), where the thickness of the road marking at any given point is generally constant across its width.
There is also known a method for applying a road marking where the thickness of the marking is varied across its width to increase the reflectivity of the road marking while preventing water from accumulating along the edges thereof during wet conditions. However, the numerous steps associated with this method render it difficult and expensive to implement. These steps include applying a traffic stripe to a road surface, applying a reflective material to the traffic stripe, applying an anti-adhesion agent to prevent adhesion between the applied traffic stripe and a deformation means passing over it, and then deforming the traffic stripe using a rotatable wheel having a plurality of projections or teeth around the periphery thereof to form spaced grooves in the traffic stripe. This method is also disadvantaged in that the grooves formed in the road stripe are a function of the tooth pattern on the rotatable wheel. Thus, when it is desired to change the pattern of the grooves formed in the road stripe, the tooth pattern on the rotatable wheel must somehow be changed, or a different rotatable wheel must be employed.
What is needed is a device and method for producing night-visible road markings having profile patterns in addition to the multi-tiered patterns discussed above, where the additional profile patterns would increase the reflectivity of the road marking during low-light and night time conditions. Preferably, such patterns could be formed in a single pass of the device over the road surface, and the profile patterns could preferably be varied “on the fly” without requiring equipment changes.
SUMMARY OF THE INVENTION
In order to solve these and other needs in the prior art, the inventors hereof have succeeded at designing and developing a device and method for applying marking material to a road surface, where the thickness of the marking material can be varied not only along its length, but across its width as well. Significantly, such markings can be formed in a single pass of the device, and the particular profile pattern of the marking can be varied as desired “on the fly” without requiring equipment changes. Moreover, a virtually limitless number of profile patterns can be implemented using the teachings of the present invention.
In accordance with one aspect of the present invention, a road marking device comprises a hopper for holding marking material, where the hopper includes an outlet for dispensing the marking material onto a road surface, and a plurality of shutters for controlling the thickness of marking material dispensed onto the road surface by the device. The shutters are preferably positioned on a rear side of the device for reciprocal movement in a generally vertical direction, and are preferably positioned adjacent to one another and configured for selective movement into different relative positions for creating a road marking having a varying thickness across its width. The device may also comprise a gate positioned on a bottom side thereof for reciprocal movement in a generally horizontal direction, and the shutters are preferably substantially aligned with the gate so as to traverse the same portion of road surface as the gate when the device is moved along the road surface. Preferably, the gate and shutters are selectively movable into sealing engagement with one another for covering the hopper outlet. The preferred number of shutters is two, although a greater number of shutters can easily be employed, if desired.
In accordance with another aspect of the present invention, in a road marking device having a bottom opening and a bottom gate selectively movable with respect to the bottom opening between open and closed positions, where the device is configured to dispense marking material through the bottom opening and onto a road surface when the bottom gate is in the open position, the improvement comprises at least two shutters substantially aligned with the bottom opening for controlling the thickness of any marking material dispensed therethrough. The shutters are preferably positioned immediately adjacent one another and rearwardly with respect to the bottom gate, and the bottom gate is preferably arranged for reciprocal movement in a generally horizontal direction, while the shutters are arranged for reciprocal movement in a generally vertical direction. The width of each shutter is preferably one-half the width of the bottom gate.
In accordance with yet another aspect of the present invention, a method of marking a road surface comprises the step of applying onto the road surface a layer of marking material having a varying thickness across its width. This applying step preferably includes the steps of applying a first stripe of marking material onto the road surface, and applying a second stripe of marking material onto the road surface adjacent to the first stripe, where the thicknesses of the first and second stripes a
Schierling Howard
Wolf Charles R.
Dunlap Codding & Rogers P.C.
Jackson Products, Inc.
Scherbel David A.
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