Apparatus and procedure for applying marking stripes

Abstract

An apparatus associated with a motor driven vehicle capable of travelling on a road surface in a direction defined by the marking line to be formed on said surface, the apparatus comprising, in combination a device for placing on said road surface a primer or bonding layer of width larger than that of the tape which has a sticky tape-receiving upper surface, means including one or more rollers for applying and pressing a marking tape on the freshly formed and still sticky bonding layer, means for positioning a temporarily protective flexible or liquid film under said roller, such that the tape and the adjacent side portions of said sticky bonding layer will remain uncovered after the passage of the roller or rollers, and means for applying a further layer of sand on the uncovered portions of the bonding layer for minimizing its adhesive characteristics and allowing immediate accessibility of the marked road to traffic. A procedure for applying the tape by using the apparatus.

Description

BACKGROUND OF THE INVENTION

a. The Field of the Invention

The present invention is concerned with the art of forming traffic dividing and regulating lines on roadway pavements by applying on and adhesively securing to the road surface a marking material, said surface having been coated with a tape receiving under-layer (or "primer" layer) of a suitable, essentially bituminous, adhesive capable of quickly setting. More particularly, this invention is concerned with a new and improved apparatus for and a novel procedure of applying a marking tape material in such a manner that the accessibility of the marked roadway to traffic will hardly be discontinued.

B. The Prior Art

The technology of providing traffic regulating lines on a road surface by applying a marking tape of essentially elasto-plastic nature thereon has been widely developed and improved in recent years, and it is now a well worked one. No extensive comments are deemed necessary on this art. Such tape materials can be laid on the road pavement by a machine which travels along the roadway with minimal disturbance of the traffic. Examples of such machines have been described in detail in Pat. Specifications Nos. 3,007,838 and 3,155,564 issued in the United States of America to the inventor of the present invention.

An important improvement over this technology has consisted of preliminarily forming on the road surface a smooth and impervious layer of a bitumen-based composition and then applying the tape material on such layer, principally when its composition is still substantially plastic and sticky. Means for taking advantage of such improved art have been described, for example, in U.S. Pat. Specification No. 3,262,375, also issued in the United States of America to the present inventor.

The sticky characteristic of the surface of the primer or bonding or tape-receiving layer (which is necessarily wider than the tape to be applied thereon) is of paramount importance for insuring the prompt adhesion of the tape. Such an adhesive characteristic leads, however, to serious drawbacks. Although the most recent compositions and procedures of forming such bonding layers provide for a very prompt setting thereof and for a nearly immediate stabilization of the tape thereon, the side portions of the layer, uncoated by the tape, maintain their noticeably sticky character for an undesirably long time. Therefore, parts and fragments of such uncoated portions not only will stick on the surfaces of the roller or rollers employed for positioning and pressing the tape on the layer, but will also stick on the wheels of traffic vehicles thus damaging the marking, prejudicing the good adhesion of the tape edge portions, and spoiling the neat marginal definition of the traffic regulating line or marking.

It is therefore an object of this invention to provide a new and improved apparatus and procedure for applying marking tapes on road surfaces by providing the same with a sticky bonding layer in such a manner that the sticky nature of the surface of the uncoated portions of said layer will be immediately eliminated or at least so minimized after the laying down of the tape, so as to obviate such drawbacks and to promply restore the availability to traffic on the freshly marked portions of the roadway.

BRIEF SUMMARY OF THE INVENTION

According to the invention, there is provided an apparatus including means for and a procedure comprising steps of (i) providing a temporarily protective film under the roller means arranged and employed for applying and pressing the tape material on a preliminarily and freshly applied bonding layer on the road surface, (ii) causing the portions of said layer, not coated by the tape, to be uncovered after the passage of said roller means, and (iii) applying on said uncovered portions a layer of essentially powdery or finely particulated material, such as sand, adapted to immediately stick on and be incorporated in the surface of said uncovered portions of the primer layer so that the undesirable sticky character thereof will be eliminated or minimized.

These and other important objects, advantages and features of the invention will be made apparent to those skilled in the art from the following detailed description of preferred embodiments of same invention. Reference will be made to the accompanying drawings.

BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWINGS

FIG. 1 is a diagrammatical cross-sectional illustration of a marking tape applied according to the invention on a roadway pavement;

FIG. 2 is a simplified longitudinal vertical sectional view of an apparatus embodying the principles of the invention, the structural details being omitted as easily conceivable, if individually considered, by those skilled in the art to which this invention appertains;

FIGS. 3 to 7 inclusive are fragmentary sectional views and partly side views of several embodiments of the device provided for forming the said layer of powdery material, FIG. 6 being a cross-sectional view taken in the plane indicated at VI--VI in FIG. 5;

FIG. 8 is a fragmentary view, seen in a direction parallel to that defined by the applied tape, of a preferred arrangement of said device; and

FIGS. 9 to 12 inclusive are diagrammatical perspective views of several arrangements adapted for positioning the said temporarily protective film under the said roller means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to FIG. 1, there is shown a tape material 10 applied on and partially embedded into, according to prior art, a freshly applied bonding or primer layer 12 on a road surface S. In view of having the tape 10 firmly secured to the road pavement and of having the side edges of same tape 10 fully protected, the bonding layer 12 has a width Ls noticeably larger than the actual width Lm of the tape 10, so that precise relative lateral positioning of the tape and of the layer can be taken into account and compensated for.

Therefore, noticeably wide side portions 12s of the bonding layer 12 remain uncovered by the tape. The uncovered portions causes the above described drawbacks when the tape material was applied according to prior art. According to an essential feature of the invention, a further layer 14 of essentially powdery material, as sand, is then applied on the previously applied tape and bonding layer, spanning a width Lp larger than the width of the bonding layer. The feature of the provision for applying such a further layer 14 consists in the complete covering of the surface of the uncovered portions 12s of the bonding layer in order to minimize the sticky character thereof.

On the other hand, it is evident that such a sticky character is disadvantageous for the surface of the roller means employed for applying and pressing the tape 10 on and into the bonding layer 12. It is also evident that the same or similar powdery material cannot be applied on the bonding layer 12 before the application of the tape 10 thereon, because such an early application of the sand will prevent critical optimal adherence of the tape to the bonding layer.

According to a further critical feature of the invention, the surface of said roller means and/or of the tape material are provisionally and temporarily protected by positioning a suitable film under said roller means as said latter means rollingly engages the marking tape being laid and pressed on the freshly formed primer layer.

FIG. 2 illustrates a typical combination and arrangement of parts, components, and devices in an apparatus according to the principles of the invention and comprising a wheeled frame structure designed to be followed by a motor driven vehicle (not shown) on which the various sources of energy (electrical, pressurized fluids and so on) and storage means for the various materials to be applied on the road surface are located.

The illustrated apparatus comprises a tape applying roller 16 and a tape pressing roller 18, arranged for operating upstream of a suitable device D which is adapted to lay the bonding layer 12 on the road surface S. The direction of the motion of the apparatus is indicated as A. The temporary protective film consists of a thin film 20 continuously unwound from a coil 22, guidedly passed under the rollers 16 and 18, and then taken-up in another coil 24, whose outer surface is frictionally engaged with the surface of roller 18 for taking-up such film at the speed at which the vehicle travels in direction A. This thin film 20 may consist of a thin continuous polyethylene strip, any other suitable plastic material or any non-plastic material, such as waxed paper.

After the passage of the last ground engaging roller (roller 18, in FIG. 2), the side portions 12s of the bonding layer 12 remain uncovered. A metered stream 30 of powdery material, such as sand, is issued from the lower outlet 32 of a suitable feedbox connected to a known vibrator 34 and supplied through a duct 36 from a supply container 38. The flow of the stream 30 of sand can be preferably controlled discontinued by means of a plug 40 controlled by a fluid operated actuator 42.

The means for discontinuing the flow of stream 30, such as the plug 40, are evidently actuated in proper phase relationship with the discontinuance of the bonding layer and marking tape application. Such a discontinuance is preferably achieved (according to the art) by discontinuing the supply of device D, raising the roller 16, supported by a rearwardly swingable brace 44 connected to an actuator 46, and operating a cutter device 48 which transversally cuts the marking tape 10.

Different devices can be employed for metering the issuance of the stream 30 in the proper direction and the feed rate for forming the layer 14 which minimizes the sticky nature of the uncovered portions 12s of the bonding layer 12, as soon as the tape 10 has been pressed thereon and adhesively engaged thereto. As shown in FIG. 3, the device comprises a feedbox 52 adapted for storing a suitable amount 50 of sand. A stream of pressurized air is fed through a duct 54 controlled by a fluid actuated valv 56 at the bottom of the feedbox and the powdery material is carried in suspension through an outlet duct 58 to nozzle means 60. The stream 30 is metered by suitably adjusting the pressure and/or the rate of the pressurized air from duct 54.

As shown in FIG. 4, the feed rate of the stream 30 is controlled by rotary adjustment of a rotary slot-type valve 64 located at the bottom outlet of a feedbox 62, wherein the downward motion of the sand 50 can be insured by a vibrator (not shown).

As shown in FIGS. 5 and 6, the feedbox 62 is provided with a grooved roller 66 located in its bottom outlet 68 and rotated via a gearing 70 by a suitably variable speed fluid or electric motor (not shown). The rate of flow of the stream 30 is metered by adjusting the rotary speed of the grooved roller 66. The rate may be discontinued by discontinuing such rotation.

As shown in FIG. 7, the stream 30 of sand is issued through a slot outlet 74 formed at the bottom of a feedbox 72 having a stationary bottom portion 76 downwardly converging over a vibratable slat portion 78 vibrated by a vibrator 82. Another vibrator 80 provides for proper downward motion of the sand 50 within the feedbox. The rate of flow of the stream 30 is adjusted by adjusting the speed and therefore the vibrational energy of vibrator 82.

FIG. 8 provides an example of selective placement of the sand to provide the layer 14 (FIGS. 1 and 2) in the location of interest only. The controlled outlet means (such as that of FIGS. 5 and 6) comprise two separate parts whiich provide individually two streams 30a and 30b directed to cover with excess sand, the uncovered portions 12s of the bonding layer. Such streams 30a and 30b are spaced by an interval I smaller than the width Lm of the tape 10.

The said temporarily protective film under the roller means can also be selectively provided by employing various means. FIG. 9 illustrates an arrangement adapted for an apparatus of the type shown in FIG. 2. The polyethylene film 20 is supplied in direction B by a guide roller 86 under the applying roller 16 concurrently with the tape 10 and guided by a roller 84. FIG. 9 illustrates also that the film 20 might be advantageously wider than the width Lm of the tape or may at least partially cover the uncovered portions of the primer layer 12 (FIG. 1), so that the edges of the tape, in service on the road surface, will remain clean and neatly defined.

FIG. 10 illustrates another embodiment in which the apparatus comprises one roller 16 which performs both the applying and the pressing of the tape 10. In this embodiment the film 20 is taken-up immediately rearwardly of said one roller in the direction C for being rewound.

FIG. 11 illustrates a further embodiment. The protective film consists of a belt 88 driven in a closed loop about the applying and pressure roller 16 and a guide roller 90. Of course, if the apparatus further comprises two or more pressure rollers (such as roller 18 of FIG. 2), the closed loop will circumscribe all the rollers of the apparatus. Alternatively a corresponding arrangement can be individually provided for protecting each roller. Suitable cleaning means, such as a motor driven rotary brush 92, are provided for continuously cleaning the belt 88. Such a belt may consist of a suitable fabric of synthetic fibers, a fine mesh textile network, a fine net or screen of metallic wires, or also a flat flexible metallic or plastic band.

FIG. 12 illustrates a still further embodiment for forming the protective film. In this embodiment, the film is a liquid film continuously re-formed on the surface of roller 16 (or of the other rollers provided in the apparatus, if any) by means of wetting roller 94 made of spongy material and meteredly fed through a duct 96 and a rotary coupling 98 with a suitable liquid adapted to prevent or minimize the adhesion of bitumen-based compositions on the thus protected roller. Such liquid may consist of an aqueous solution of a soap or of another agent possessing surface activity, such as an alkyralic suphonate. The spongy wetting roller 94 can be rotated, for example, by the same roller 16 by means of a suitable transmission belt 100.

The liquid film prevents dirt, bitumen fragments, and so on from sticking to the surface of the roller 16 (or of any other thus protected roller). The film, the dirt, and the fragments carried therein are continuously removed by suitably scraping means, such as a doctor blade 102, a rotary brush (such as that indicated at 92 in FIG. 11), or other suitable means. It has been found that the wetting of the uncovered portions 12s of the primer layer 12 (FIG. 1) does not prejudice the prompt penetration of the powdery material thereinto, but also facilitates the cleaning of the upper surface of the marking tape.

Claims

I claim:

1. In an apparatus for applying traffic lines and markings on a road surface, a combination comprising means for placing a bonding layer on the road surface, said bonding layer having an adhesive upper surface when freshly formed; means including a first and second roller means for applying and pressing a marking tape of a width less than the width of said bonding layer onto said adhesive upper surface while the apparatus travels on the road surface; means for temporarily positioning a protective film intermediate said roller means and said marking tape and adhesive upper surface where said roller means contacts said marking tape and the adjacent uncovered lateral portions of said bonding layer; and means for depositing a layer of powdery material on at least said uncovered lateral portions so as to become embedded in the uncovered portions of said bonding layer to minimize the adhesiveness of said upper surface of the latter.

2. The apparatus as defined in claim 1, wherein said positioning means comprises a delivery coil, a take-up coil, and roller guide means positioned and driven for continuously supplying said film in the form of a thin strip of flexible material under said first roller means which engages said tape intermediate said roller means and said tape, and for concurrently continuously removing said film from above said tape downstream to said second roller means which presses on said tape.

3. The apparatus as defined in claim 1, wherein said positioning means further comprises a temporarily film forming strip of flexible material arranged in a closed loop circulating about said roller means which applies and presses said tape on said bonding layer, and cleaning means positioned for frictionally engaging the outer surface of said closed loop at a position spaced from the part of said loop adjacent to said tape for continuously removing from said strip any substance which may have been stuck on said strip where engaged with said tape and said uncovered portions of said bonding layer.

4. The apparatus as defined in claim 1, wherein said closed loop film forming strip consists of a fine flexible network.

5. The apparatus as defined in claim 1, wherein said positioning means further comprises wetting means positioned for continuously applying and re-forming a liquid film on the surface of said roller means which applies and presses said tape on said bonding layer, and dirt and liquid film removing means engaging the surface of said roller means after said surface has engaged said applied tape and said uncovered portions of said bonding layer.

6. The apparatus as defined in claim 1, wherein said depositing means comprises a feedbox adapted to store a supply of said powdery material, said feedbox being connected to outlet means positioned above said uncovered portions of said bonding layer, downstream of said roller means which has applied and pressed said tape on said layer, and valve and metering means cooperatively associated with said outlet means for meteredly issuing streams of said powdery material from said outlet means onto said uncovered portions.

7. The apparatus as defined in claim 6, wherein said feedbox has a source of pressurized air connected to its lower portion, and said outlet means is connected to the upper portion of said feedbox whereby a stream of air will transport in suspension said powdery material.

8. The apparatus as defined in claim 6, wherein said feedbox has said outlet means at its lower portion, and issuing and metering mechanical means are cooperatively arranged in said outlet means.

9. A method of applying traffic lines and markings on a road surface, comprising the steps of placing a bonding layer on the road surface, said layer having an adhesive upper surface when freshly formed; applying and pressing with rolling means a marking tape of a width less than the width of said layer onto said adhesive surface; temporarily positioning a protective film intermediaate said roller means and said tape and said adhesive surface to prevent contact of said roller means with the uncovered portions of said surface laterally of said tape; and depositing a layer of powdery material onto at least said uncovered portions for embedding in said uncovered portions of said upper surface of said bonding layer to minimize the adhesiveness of said upper surface.

10. The method as defined in claim 9, wherein said temporarily protective film consists of a continuous thin strip of flexible material continuously fed under said roller means which applies and presses the tape on the bonding layer inermediate said roller means and said tape, and wherein the step of positioning a protective film further includes the step of concurrently continuously taking-up said film from under said roller means which has pressed said tape onto said bonding layer.

11. The method as defined in claim 9, wherein the step of positioning said temporarily protective film includes the steps of forming a liquid film made of a solution of an agent having surface tension properties, continuously applying and re-forming said liquid film on the surface of said roller means, and continuously removing therefrom together with any substances which have contacted said surface.

12. The method as defined in claim 9, wherein the step of depositing said powdery layer includes the step of forming at least one stream of sand on the surface of the uncovered portions of said bonding layer.

13. The method as defined in claim 12, wherein said step of forming said stream of sand includes the step of transporting said sand in suspension by means of injecting a pressurized air stream through said sand.

14. The method as defined in claim 12, wherein said step of forming said stream of said includes the step of arranging mechanical means so as to cooperate with an outlet of a storage means wherein an amount of sand is stored.

15. The method as defned in claim 1, wherein said step of arranging mechanical means includes the step of vibrating said outlet of said storage means so as to cause said stream of sand to issue.