US3902666A

US3902666A - Line marker

Info

Publication number: US3902666A
Application number: US388268A
Authority: US
Inventors: Hiroshi Ito; Masaharu Fukushima
Original assignee: Sakai Chemical Industry Co Ltd
Current assignee: Sakai Chemical Industry Co Ltd
Priority date: 1972-08-28
Filing date: 1973-08-14
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02

Abstract

A line marker for applying a marking material of the fusion type onto the roads in a molten state to provide marking lines thereon. The marker includes a rotary pressurizing machine for eliminating the thixotropic properties of the marking material to enable an applicator to spray the molten marking material onto the pavement smoothly and assures satisfactory adhesion of the marking material to the pavement.

Description

1 1 a :1 1' 1 1 111m Stes atent 11 1 1111 3,902,666

100 et a1. Sept. 2, 1975 [54] LINE MARKER 2,808,048 10/1957 Garrison 239/129 X 2,833,542 5/1958 Martin 239/150 X [75] Invemors: Hlmsh' OWaZUNShIYama; 3202 359 8/1965 Gill Jr. 239/150 x Masahaw Fukushlm, Sakah both 3,477,352 11/1969 Harding et al. 239/305 x of Japan FOREI N PATENTS R APP ICAT N [73] Assignee: Sakai Chemical Industrial (10., Ltd., G L IO S Ja 783,187 9/1957 United Kmgdom 239/130 pan [22] Filed: 1973 Primary ExaminerM. Henson Wood, Jr. [21] Appl. No.: 388,268 Assistant Examiner-John J. Love Attorney, Agent, or F irm-Joren, McGeady and St [30] Foreign Application Priority Data anger Aug. 28, 1972 Japan 47-100700 Aug. 18, 1972 Japan 47420779 ABSTRACT A line marker for applying a marking material of the [52] US. Cl. 239/130, 239/176, 404/94, fusion type Onto the roads in a molten State to provide 404/111 marking lines thereon. The marker includes a rotary pressurizing machine for eliminating e otrop c [58] Field of Search 239/130, 131, 125, 135, properties of the marking material to enable an appli 239/142 404/94 cator to spray the molten marking material onto the pavement smoothly and assures satisfactory adhes1on of the marking material to the pavement. [56] References Cited UNITED STATES PATENTS 7 Claims, 4 Drawing Figures 1,089,145 3/1914 McDonald 239/129 PATENTEDSEP 2l975 3. 902,666

suwuufg LINE MARKER This invention relates to a line marker for spraying mainly a marking material of the fusion type onto the road surfaces to draw center lines, lane lines and no passing markings and like pavement markings, more particularly to a line marker comprising a vehicle such as a truck carrying thereon a melting tank and a reservoir and provided in its rear with a spray gun or like spray means, wherebya thermoplastic pavement marking material is heated to a molten state and the molten material is then sprayed onto the road surfaces to provide markings thereon.

Line markers have already been known by which a thermoplastic pavement marking material is melted by heating and then sprayed onto the pavement in a mol ten state. Further known as the methods for spraying the molten thermoplastic pavement marking material are the airless spray type and air spray type.

The former airless spray method employs an apparatus including a melting tank, a reservoir adapted to maintain the molten marking material at a constant temperature and having a reciprocally driven pump to force out the marking material and a spray gun, so that the molten marking material is forcibly sent to the spray gun and is thereby sprayed onto the pavement at a high pressure in an airless fashion. According to the latter air spray method, the interior of the reservoir is pressurized to force out the molten marking material therefrom and the marking material is then sprayed by a spray gun with compressed air which is supplied sepa rately.

The reservoir employed in these conventional methods is equipped with a stirrer for stirring the marking material evenly so as to maintain the whole material at a uniform and constant temperature and to destroy thixotropy to be described later.

Generally, pavement marking materials heated to a molten state are in the form of slurry containing a large amount of fine particles of pigment and extender suspended therein, so that the particles are anisotropic in shape and tend to be bonded together loosely by a bonding force acting therebetween to form a gel. Although stirring breaks down the internal bonds of the gel to give an increased fluidity, the particles will be bonded to one another again when left to stand. Thus the marking materials have so-called thixotropy." The stirrer therefore fluidizes the marking material to a vis cous fluid within the reservoir but, while the fluid flows through a conduit from the reservoir to the spray gun, the particles become bonded together as described above in the vicinity of the conduit wall Where the flow rate is relatively low, with the consequent drawback that the flow of material through the conduit will be interrupted.

In order to overcome such drawback, the former of the conventional methods employs a reciprocally driven pump giving a high pressure of 100 to 140 kg/cm which. however, entails the disadvantage of requiring a very large compressor that is inefficient and costly to operate. hence uneconomical. Moreover, the marking material of the fusion type becomes more viscous and solidified rapidly as the temperature drops and does not permit the use of a conventional accumulator because of the high temperature and high pressure. It is therefore impossible to eliminate a pulsating phenomenon at the upper and lower extremities of stroke of the plunger and to produce a uniform spray pattern. On the other hand, the latter method needs fairly large amounts of atomizing air and inducing air inasmuch as the marking composition is highly viscous and thixotropic. In fact, the amount of air forced out from the spray gun is several hundred times the volume of the sprayed marking composition and exceeds the amount generally used for coating operations. The excess of air gives an indistinct spray pattern with blurred margins.

According to the latter method, the excess air further supercools the marking material emanating from the spray gun before it reaches the surface of pavement, permitting part of the material to undergo solidification and thereby impairing its adhesion to the pavement.

With the latter method, moveover, it is necessary to open an air supply valve and to close an exhaust valve every time the molten material is supplied to the reservoir, this resulting in the drawback that the spraying operation has to be interrupted for every batchwise op eration.

It is also known to firmly bond the sprayed marking material to the pavement with a coating of adhesive provided before the marking material is applied thereto. The adhesive is applied by a spray gun disposed in front of the spray gun described above. it is also proposed to mount the spray gun for applying the adhesive on another vehicle preceding the line marker so that when a suitable amount of volatile component of the adhesive has evaporated off the marking material is sprayed and glass beads are fixed to the unhardened coating of the adhesive.

According to the former method, however, the distance between the adhesive spray gun and the marking material spray gun is limited and the marking material is applied immediately after the application of adhesive. Consequently, the liquid marking material heated to a high temperature of to 230C will be applied to the adhesive in which the volatile component still remains unevaporated, causing the lowerboiling volatile solvent to evaporate off in an explosive fashion to pass through the coating of marking material, whereby numerous pinholes will be formed to reduce the area of adhesion. This markedly impairs the adhesion especially during winter. The latter method requires, in addition to a line marker, another vehicle and the operation involves the diffieulty that the preceding vehicle must be spaced from the following line marker by a correct distance in order to permit the adhesive to dry spontaneously for the most effective adhesion. Moreover, if another vehicle should come in or pass between the two vehicles, the vehicle will remove the adhesive with its tires, leaving a portion where the effectiveness of adhesive is reduced greatly.

The present invention has been accomplished to eliminate the foregoing drawbacks of conventional line markers.

A main object of this invention is to overcome the above-stated drawbacks due to thixotropy, to enable a spray gun to apply a marking material in a molten state reliably all the time so as to give a uniform spray pattern, to eliminate the phenominon of pulsation that is a drawback of the airless spray method described and to reduce the amount of compressed air required for the use of a spray gun of the air spray type so as to improve the spray pattern and adhesion to the pavement.

Another object of this invention is to provide a line marker including a melting tank in the form of a pressure-resistant container so that the marking material heated to a high temperature and melted to a liquid state can be forced into a reservoir with safety and without a heat loss by a pressure fluid forcibly introduced into the melting tank, the line marker thus being capable of spraying the marking material in a molten state continuously.

Another object of this invention is to provide a line marker for bonding the marking material to the pavement with an adhesive which marker permits the adhesive to exhibit its ability to a full extent and to thereby improve the adhesion of the marking material to the pavement so that the marking material can be bonded to the pavement reliably and firmly.

Still another object of this invention is to provide a line marker for spraying nighttime reflecting glass beads onto the surface of marking material coating on the pavement which marker is capable of placing the beads to a proper depth from the surface of the coating irrespective of the atmospheric temperature and the temperature of the pavement.

The novel construction of this invention is set forth in 'the appended claims, and the detailed construction of the invention will be fully understood from the embodiments described below with reference to the accompanying drawings in which:

FIG. 1 is a side elevation showing a line marker embodying the present invention;

FIG. 2 is a schematic view showing the system for spraying a pavement marking material in a molten state;

FIG. 3 is an enlarged view showing the applying means of FIG. 1; and

FIG. 4 is a rear view of the same.

With reference to the drawings, the line marker of this invention will be described. Indicated at is a motor truck or like vehicle carrying on its loading platform, from front to rear, an air compressor 1, an LPG container 4, a melting tank 2 for melting a marking material a, a reservoir 3 for maintaining the marking material a at a constant temperature in a molten state, an adhesive container and a glass bead container 6. The vehicle 10 is further provided at its rear lower portion with applying means 7 for spraying the marking material 0 onto the surface of road in a molten state. These means constitute the line marker of this invention as a whole.

The melting tank 2 is in the form of a pressureresistant container. The tank 2 has an inlet 21 having a cover 27 and positioned in its upper shoulder portion for feeding a solid or powdery thermoplastic marking material a and a stirrer 22 at its center. Disposed under the tank 2 is a heater 23 which burns LPG supplied from the LPG container 4.

An air duct 24 communicating with an air compressor 1 extends from a shoulder portion of the melting tank 2 to introduce compressed air from the air compressor 1 into the tank 2 and to thereby force the molten marking material into the reservoir 3. More specifically, the marking material a charged in through the inlet 21 is melted to a liquid state by the heater 23, and the liquid marking material is forced by the action of the compressed air into the subsequent reservoir 3, wherein the molten material a is maintained at a constant temperature for storage. A conduit 25 extending approximately from the bottom of the melting tank 2 has a valve 26 and is connected to the upper shoulder portion of the reservoir 3. The reservoir 3 includes at its center a stirrer 31 for agitating the stored marking material 2.

Located under the reservoir 3 is a heater 32, similar to the above, which is adjusted to maintain the marking material a at a constant temperature.

The reservoir 3 is likewise in the form of a pressureresistant container. As is the case with the melting tank 2, part of the compressed air from the air compressor 1 is introduced into the reservoir 3 by way of an air duct 33 to pressurize the liquid marking material 2. The

air ducts

24 and 33 are provided at their intermediate portions with

pressure regulators

28 and 34. If the regulator 34 for the reservoir 3 is set for a lower pressure value than the regulator 28, the marking material a can be supplied from the conduit 25 to the reservoir 3 even during a spraying operation by opening the valve 26 on the conduit 25. Indicated at 24a and 33a are air supply valves, and at 24b and 33b exhaust valves.

The marking material a liquefied at a high temperature is applied by the applying means 7 onto the road in a molten state. As shown in FIG. 2, the applying means 7 comprises spray means which may typically be a spray gun as shown in FIG. 2 or the combination of an adhesive applicator and a spray gun 71 as seen in FIG. 3.

The spray gun is a spray means of the known type which is positioned in the rear of the vehicle 10 and supported on a support frame 40 to be described later. The spray gun is connected to the reservoir 3 by a conduit 8 and has a nozzle at its front end directed to the road surface, whereby the liquid marking material a forced out from the reservoir 3 through the conduit 8 is sprayed onto the road surface.

A return duct 9 extends from the spray gun to an upper shoulder portion of the reservoir 3 and has at a position close to the reservoir 3 an escape valve 91 of the pressure regulating type. The back pressure, namely the opening degree of the valve 91 is controlled to return the excess of supplied liquid marking material a to the reservoir 3 and to control the spraying pres sure, whereby the material is sprayed from the spray gun in a stable fashion. Usually, the marking material a is supplied in an amount greater than is used, and during operation the hot marking material a flows through the return duct 9 all the time irrespective of whether the nozzle of the spray gun is opened or not to prevent the spray gun from cooling.

The escape valve 91 has the same construction as a reducing valve to regulate the pressure within the return duct 9. The valve 91 is regulated to control the back pressure in the return duct 9 and to thereby control the spraying pressure of the spray gun. The control thus effected assures satisfactory spray patterns over a fairly wide viscosity range of the molten marking material.

Indicated at 72 is an air duct for supplying compressed air from the air compressor 1 to the spray gun 71 to operate the gun and is provided at its intermediate portions with a pressure regulator 77 and an air valve 78 for controlling the flow of air forced into the spray gun 71.

Another type of the applying means 7 comprises the combination of the spray gun and an adhesive applicator and is superior to the use of the spray gun alone in assuring bonding. Prior to the application of the marking material a by the spray gun, the applicator applies an adhesive to the surface of the road. Along with the spray gun 71, the applicator is mounted on the support frame 40 to be described later and comprises a spray gun 73 for applying the adhesive and a burner '74 for heating the applied adhesive. The conjoint use of the burner 74 assures effective bonding and eliminates the drawbacks heretofore experienced with this type of de vice. The spray gun 73 is designed to apply the adhesive to the pavement over the same width as or over a greater width than the spray gun 71. The burner 74 burns LPG supplied through a gas duct 740 connected to the LPG container 4 to positively evaporate off the solvent and like volatile component from the adhesive coating on the pavement and to thereby render the surface of the coating most optimum for adhesion.

The burner 74 is surrounded by a metal cover 75 for reflecting the flame and concentrating the combustion gas. Extending from the lower portion of the cover is an asbestos curtain 76 for preventing the combustion gas from spreading forward and backward.

Before the application of the marking material with the spray gun, the adhesive is applied by the adhesive applicator of the construction described and the surface of the resulting coating of the adhesive is heated by heating means which is typically the burner 74 to evaporate off a suitable amount of volatile content from the adhesive and to thereby assure the highest adhesion. The marking material in molten state is then applied by the spray gun 71 to the surface of the adhesive coating in a molten state, whereby the marking material can be bonded to the pavement with greatly improved adhesion.

A pressurizing machine 11 of the rotary type is disposed at an intermediate portion of the conduit 8 for supplying the liquid marking material a from the reservoir 3 to the applying means 7. It is located at such position that the particles of the fluidized marking material a passing through the conduit 8 have not been bonded again.

The pressurizing machine 11 is an important element of this invention. The provision of the machine 11 on the conduit 8 intermediately thereof eliminates any discontinuity of the flow of the material through the conduit 8 due to the thixotropic properties, permitting the spray gun 71 to spray the material in a molten state continuously to give a stable spray pattern all the time.

Chiefly, the machine 11 is a gear pump, screw pump, vane pump, snake pump or like rotary machine which is capable of vigorously agitating the liquid marking material a to change the gelling properties of the material in the conduit 8 to solating properties and to increase its fluidity, the machine further being capable of applying pressure to forcibly send the material forward. Our experiments have revealed that a gear pump, especially an internal gear pump, is most suitable to use. A valve 12 is mounted on the conduit 8 between the outlet of the reservoir 3 and the rotary pressurizing machine 11 to interrupt thesupply of the marking material after completion of operation.

The support frame 40 carries the applying means 7 at the rear portion of the vehicle in upwardly and downwardly movable manner. The frame 40 comprises the assembly of horizontal beams 41, upright columns 42 on the beams 41 and beams 43 fixed to the upper ends of the columns 42 and is supported by lift arms 46 and 47 through

bearings

44 and 45.

The lift arms 46 and 47 are connected to link

arms

48 and 49 respectively and are supported by

rods

50 and 51 for pivotal movement about the

rods

50 and 51. The

rods

50 and 51 are supported by

plates

61 and 62 fixed to a stationary member 60.

An air cylinder 52 is interposed between the link arm 48 and the plate 62, and a link 53 is provided between the

link arms

48 and 49 to deliver the movement of the air cylinder 52 to the link arm 49, the arrangement being such that the air cylinder 52;, when operated, moves the support frame 40 upward of downward through the

link arms

43 and 49 and lift arms 46 and 47 while maintaining the frame 40 in a horizontal position. The length of the link 53 is adjustable as desired by an adjusting screw 54.

The support frame 40 carries ground wheels 55 having rubber tires to support the frame 40 at a predeter mined level when the frame 40 is lowered.

If the pressure of the air cylinder is adjusted when the support frame 40 is to be lowered, the air cushion afforded by the cylinder 52 serves to mitigate the impact transmitted through the ground wheels 55. Thus the air cylinder 52 acts as an ideal shock absorber, permitting the spray gun on the frame 40 to produce a very distinct spray pattern.

The support frame 40 constructed as above carries, from the front to the rear, the spray gun 73 for applying adhesive b, burner 74 for heating adhesive and spray gun 71 for applying marking material to provide the applying means 7. As will be apparent from FIG. 3, the spray guns and burner 74 are positionable by racks 56 and pinions 57 at varying levels individually independently with respect to the surface of the road. Indicated at 58 are handles for rotating the pinions.

When drawing a marking line at a work site, the air cylinder 52 is operated from the drivers cab of the vehicle to lower the support frame 40 and the spray guns and burner 74 are adjusted to optimum levels in conformity with the conditions at the site. After operation, the frame 40 is elevated to permit the frame 40 to clear projections on the road so that the vehicle can travel free of trouble.

The present apparatus further includes a spray gun 63 for glass beads c. Disposed immediately behind the spray gun 63 is a propane gas heater 64 of the heat radiation type as an example of means for controlling the degree to which the glass beads are to be embedded into the coating. When marking lines are drawn in a cold district during winter, glass beads are forced into the surface of unhardened marking material and the 1 surface is then heated by the heater 64 to prevent rapid hardening of the marking material, permitting the glass beads to be embedded into the marking material by more than half their diameter. During winter, the heating also serves to prevent the marking material of the fusion type from embrittlement due to internal strain caused by rapid cooling.

The heater 64 is provided with a heat radiation reflecting plate 65 by which the heat radiation is effectively concentrated onto the surface of the marking material.

Each of the burner 74 and heater 64 is provided with a temperature or pressure regulator to control the amount of LPG to be burned and to thereby control the heating temperature.

During a very hot season in summer, the thermoplastic marking material sprayed from the spray gun 71 will take an extremely prolonged time to harden and the glass beads placed on its surface will sink to excess. This is prevented by replacing the LPG heat radiation heater 64 by a cold water spray gun which controls the depth to which the beads are to be embedded.

According to the construction of the airless spray type described, the air flowing through the air duct 72 and electromagnetic valve 78 is used only for opening ad closing the spray gun nozzle. The spraying pressure is determined by the internal pressure of the reservoir 3 and the pressure applied by the rotary pressurizing machine 11. Accordingly, the spraying pressure can be readily controlled by varying the speed of rotation of the rotary pressurizing machine 11, or by adjusting the pressure regulator 34 for the reservoir 33, or by adjusting the pressure regulator 91 on the return duct 9, whereby a satisfactory spray pattern will be obtained.

To apply this invention to a spray gun of the air spray type, the airless spray gun 71 is replaced by an air spray gun. The air is then used for opening and closing the air spray gun, for induc.'ton of the marking material and for spraying and atomization. The pressure of the marking material can be easily controlled similarly by varying the speed of rotation of the rotary pressurizing machine 11 or by adjusting the pressure regulators 34 and 91. Even with the use of the air spray type spray gun, the provision of the powerful pressurizing machine 11 of the rotary type minimizes the amount of air for atomization to prevent supercooling of the sprayed thermoplastic marking material, giving a much more distinct spray pattern and higher adhesion to the pavement than conventional air spray devices,

To spray the marking material a onto the pavement in a molten state using the embodiment described, a predetermined amount of the thermoplastic marking material in a solid or powder form is placed into the melting tank 2 from the inlet 21 and is then liquefied by driving the stirrer 22 and operating the heater 23. The cover 27 and exhaust valve 24b are thereafter closed and the air supply valve 24a is opened to introduce compressed air into the tank and to transfer the liquid marking material a from the pressurized tank to the reservoir 3 through the conduit 25.

The liquid marking material thus sent into the reservoir 3 is maintained at a constant temperature therein by virtue of rotation of the stirrer 31 and heating by the heater 32.

In the course of or upon completion of transfer of the liquid marking material a, the exhaust valve 33b is closed and the air supply valve 33a is opened to pressurize the interior of the tank 3, forcing out the material through the conduit 8 extending from the bottom of the reservoir. The material passes through the valve 12 into the rotary pressurizing machine 11, where it is further pressurized and agitated at the same time. This destroys the thixotropy, and the material is sent forward as a completely viscous fluid under an increased pressure, flows through the conduit 8 at a continuous flow rate and reaches the applying means 7. The marking material is therefore sprayed from the spray gun 7] in a molten state under controlled conditions to give a desired spray pattern.

In the foregoing spraying operation conducted by the spray gun, an adhesive may be applied and then heated by the burner 74 to an optimum state to cause the marking material to bond to the pavement firmly as already described.

In the case where a glass beads spray gun 63 is disposed immediately behind the spray gun 71 for applying the marking material, glass beads are placed by the spray gun 63 into the surface of unhardened coating of marking material after the application of the marking material. During a very cold season in winter, the heater 64 makes it sure to retain the beads in the embedded position and prevents embrittlement of the marking due to internal strain caused by rapid cooling, whereas during a hot summer season the heater 63 may be replaced by a cold water spray gun which promotes hardening of the beads bearing coating surface to prevent complete embedding of the beads. In this way the beads can be embedded to an optimum degree in whatever season to give a marking line which is highly reflective at nighttime.

As described above, the present invention makes it possible to eliminate any influence of the peculiar property of the pavement marking material, namely the thixotropy thereof, by the rotary machine provided at an intermediate portion of the conduit, enabling the liquid marking material to flow from the conduit to the spray gun or like spray means with extreme smoothness, good stability, in a continuous manner and free from pulsation and 'vibration unlike conventional apparatuses. Consequently, the spray gun produces uniform and distinct spray patterns all the time.

Furthermore the present invention can be applied to either airless spray type gun or to air spray type gun to give uniform and distinct spray patterns.

In the case where the marking material is bonded to the pavement with a coating of adhesive, the adhesive coating is heated by a heater to cause the volatile component of the adhesive to evaporate off, permitting the adhesive to give the highest adhesion, whereupon the marking material is applied to the adhesive coating. Consequently, although the operation can be effected by one line marker, the marking material can be bonded very satisfactorily with improved adhesion.

Briefly, the present invention makes it possible to provide pavement markings under most ideal conditions in any season and to maintain the same state correctly. In addition, the invention assures an efficient operation since the whole operation is performed by one line marker.

What we claim is:

l. A line marker assembly for spraying onto a road surface a thermoplastic road marking material having thixotropic properties and containing pigments and extenders in a molten state so as to provide a traffic marking line, said assembly comprising, in combination: an automotive vehicle having a loading platform; a melting tank mounted on said loading platform for melting therein road marking material; a reservoir mounted on said loading platform and connected to receive molten marking material from said melting tank for maintaining molten the marking material contained therein at a constant temperature; spray means supported upon said vehicle for spraying molten marking material onto a road surface; first conduit means for supplying molten marking material therethrough from said reservoir to said spray means; compressed air supply means; means for applying compressed air from said supply means to said reservoir to pressurize said reservoir and thereby effect transfer of said marking material from said reservoir to said spray means through said first conduit means; and a pressurizing device of the rotary type connected within said first conduit means between said reservoir and said spray means for agitating and disintegrating said marking material to overcome viscosity effects therein of said thixotropic properties thereby to provide smooth viscous flow of said marking material to said spray means.

2. An assembly according to claim I wherein said pressurizing device is a gear pump.

3. An assembly according to claim 1 including second conduit means defining a flow path for said molten marking material from said melting tank to said reservoir, and means for applying compressed air from said supply means to said melting tank to pressurize said melting tank thereby to effect transfer of said marking material from said melting tank to said reservoir through said second conduit means.

4. An assembly according to claim 3 further including an adhesive applicator disposed forwardly of said spray means relative to said vehicle, and adhesive hesive heater means is an LPG burner mounted upon said vehicle to be disposed at varying levels relative to said road surface.

6. An assembly according to claim 1 including means for spraying glass beads upon. said road surface, said glass beads spray means being disposed upon said vehicle rearwardly of said spray means thereby to apply said glass beads to said road surface subsequent to application thereof of said marking meterial, and heater means disposed upon said vehicle rearwardly of said glass beads spray means for heating said marking material subsequent to application thereof of said glass beads thereby to promote imbedding of said glass beads into said marking material.

7. An assembly according to claim I particularly suitable for use during hot weather conditions including means for spraying glass beads upon said road surface, said glass beads spray means being disposed upon said vehicle rearwardly of said marking material spray means whereby said glass beads may be applied to said road surface subsequent to application thereof of said marking material, and cold water spray means disposed upon said vehicle rearwardly of said glass beads spray means to promote imbedding of said glass beads into said marking material.

* l a l UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Pa o, 3,902 ,666 Dated September 2 1975 Inventor(s) Hiroshl Ito et 31.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of patent, insert Signed and Scaled this sixteenth Day Of December 1975 Nov. 2 1972 Japan .47-109996 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Patents and Trademarks

Claims

1. A line marker assembly for spraying onto a road surface a thermoplastic road marking material having thixotropic properties and containing pigments and extenders in a molten state so as to provide a traffic marking line, said assembly comprising, in combination: an automotive vehicle having a loading platform; a melting tank mounted on said loading platform for melting therein road marking material; a reservoir mouNted on said loading platform and connected to receive molten marking material from said melting tank for maintaining molten the marking material contained therein at a constant temperature; spray means supported upon said vehicle for spraying molten marking material onto a road surface; first conduit means for supplying molten marking material therethrough from said reservoir to said spray means; compressed air supply means; means for applying compressed air from said supply means to said reservoir to pressurize said reservoir and thereby effect transfer of said marking material from said reservoir to said spray means through said first conduit means; and a pressurizing device of the rotary type connected within said first conduit means between said reservoir and said spray means for agitating and disintegrating said marking material to overcome viscosity effects therein of said thixotropic properties thereby to provide smooth viscous flow of said marking material to said spray means.

2. An assembly according to claim 1 wherein said pressurizing device is a gear pump.

4. An assembly according to claim 3 further including an adhesive applicator disposed forwardly of said spray means relative to said vehicle, and adhesive heater means disposed between said applicator and said spray means whereby an adhesive substance may be applied to said road surface and heated with subsequent application of said molten marking material thereover.

5. An assembly according to claim 4 wherein said adhesive heater means is an LPG burner mounted upon said vehicle to be disposed at varying levels relative to said road surface.

6. An assembly according to claim 1 including means for spraying glass beads upon said road surface, said glass beads spray means being disposed upon said vehicle rearwardly of said spray means thereby to apply said glass beads to said road surface subsequent to application thereof of said marking meterial, and heater means disposed upon said vehicle rearwardly of said glass beads spray means for heating said marking material subsequent to application thereof of said glass beads thereby to promote imbedding of said glass beads into said marking material.

7. An assembly according to claim 1 particularly suitable for use during hot weather conditions including means for spraying glass beads upon said road surface, said glass beads spray means being disposed upon said vehicle rearwardly of said marking material spray means whereby said glass beads may be applied to said road surface subsequent to application thereof of said marking material, and cold water spray means disposed upon said vehicle rearwardly of said glass beads spray means to promote imbedding of said glass beads into said marking material.