GB2041785A - Spraying machine - Google Patents

Abstract

A machine for spraying stripes on a substantially horizontal surface, such as a road 6, comprises ground engaging means 4 on which it can be moved over the surface and a mounting 10 for a spray gun 8, which mounting is supported by a support mechanism 16 which permits movement of the mounting but is operable to constrain such movement to a path having a component transverse to a fore and aft axis of the machine and a vertical component, whereby the mounting is movable simultaneously transversely and towards or away from said surface. This provides a simple manner of adjusting the machine to produce different stripe widths 22, 24 at different distances from the machine centre line. There may be two spray guns on the mounting 10. The spray material is preferably hot thermoplastics supplied via a conduit (28) surronded by a space (38) supplied with heated oil, Fig. 3 (not shown). <IMAGE>

Description

SPECIFICATION Spraying machine This invention relates to machines for spraying stripes on a substantially horizontal surface. It is particularly concerned with machines for spraying road marking lines or stripes. Although roads are primarily substantially horizontal they do, in parts, depart to quite a large degree from a strictly horizontal plane, for example on hills and close to the margins of some roads, and the term "substantially horizontal" in this application is to be construed accordingly.

A commonly used type of machine for spraying stripes on roads is mounted on wheels and is steerable, includes a tank for containing hot liquid thermoplastic material pius certain desired additives, and a spray gun carried on a mounting, directed towards the road, and supplied with the thermoplastic material, which material emerges from the spray gun as a diverging spray. As the machine is moved along the road the spray gun deposits a stripe of thermopiastics material on the road surface.

Stripes of different width may have to be sprayed, because regulations require that road marking stripes for different purposes should be of different specified widths. To vary the stripe width, it is known to adjust the distance between the spray gun and the ground. This changes the width of the stripe being sprayed because of the diverging pattern of the spray from the gun. It is also desirable to be able to adjust the position of the spray gun in a direction transverse to the fore and aft axis of the machine i.e. relative to the direction of travel of the machine, thereby adiusting the transverse distance between the stripe being sprayed and the fore and aft axis of the machine.

In machines that are in common use transverse movement of the spray gun has been achieved by having it clamped on a transverse bar from which it can be unclamped, shifted along the bar, and then re-clamped at a new transverse position. To achieve vertical adjustment, the mounting bar has in turn been mounted on an arrangement involving a vertical screw which, when rotated, causes the mounting bar to move vertically, this adjustment requiring many turns of the screw to achieve a substantial amount of displacement.

The invention provides a machine for spraying stripes on a substantially horizontal surface, the machine comprising ground engaging means on which it can be moved over the surface and comprising a mounting for a spray gun, which mounting is supported by a support mechanism which permits movement of the mounting but is operable to constrain such movement to a path having a component transverse to a fore and aft axis of the machine and a vertical component, whereby the mounting is movable simultaneously transversely and towards or away from said surface.

We have found that such an arrangement enables the great majority of the required adjustments of stripe width and stripe position to be made by carrying out only a single adjusting operation, instead of the two independent adjusting operations which have been required in well known machines.

Preferably, the support mechanism comprises at least one swinging link. If more than one swinging link is employed, the spray gun mounting is then preferably on a transverse member pivoted to the swinging links and extending between them.

In known machines, because the position of the gun is adjustable relative to the stationary tank from which the thermoplastic material is supplied to the gun, a flexible connection from the tank to the gun has been provided. The thermoplastic material requires to be heated as it travels from the tank to the gun in order to preserve its fluidity and consequently the flexible connection has consisted of an inner conduit for the thermoplastic material and an outer conduit through which heated oil is circulated.The exact structure of such double-walled conduits is not important for the purposes of the present invention but, in order to meet their operational requirements, they are expensive and are also somewhat stiff, this stiffness requiring that they be perhaps as much as seven or eight feet long in order to accommodate one or two feet of horizontal movement of the gun, and about one foot of vertical movement of the gun.

A further advantageous feature of the invention is that the swinging link, or one of them, may be pivoted to a fixed part of the machine by means of a pivotal joint adapted to allow flow of fluid to be sprayed, through said joint, a reservoir for said fluid being located on the machine and being coupled to said joint and the swinging link including a conduit for conducting fluid from the joint for the spray gun.

The construction of such a link can be simpler and less expensive than that of a flexible conduit, and in particular a double-walled swinging link to enable heating of the material to be sprayed can be substantially less expensive than a doublewalled flexible conduit. This economy is to a large extent due to the fact that a swinging link can be made much shorter to accommodate a given amount of gun movement, than can a flexible conduit.

In order that the invention may be more clearly understood, a preferred embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a transverse cross-section through a spraying machine in accordance with the invention, the cross-section being taken .looking towards the rear of the machine from a position between the front wheels and the rear wheels of the machine; Figure 2 is a partly cross-sectional view taken on the line li-Il of Figure 1; and Figure 3 is a cross-sectional view taken on the line Ill-Ill of Figure 1.

Figure 1 shows only those parts of the machine necessary for an understanding of the machine.

Other parts, such as the form of the chassis, the suspension, the steering and drive arrangements, the compressor for the spray material, the heat source for keeping the sprayed material heated, and the reservoir tank for the sprayed material are not shown and they may all be of conventional kind.

The machine has a chassis comprising two main chassis members extending in the fore and aft direction. The left hand one of these members is shown as 2 in Figure 1 and the other is not shown but would be at the corresponding position on the right hand side of the drawing. One rear wheel 4 of the machine is shown on the left and the other rear wheel would be at the corresponding position on the right, both these wheels being mounted on the chassis in any suitable manner. The forward direction of movement of the machine over a road surface 6 is perpendicularly to the plane of Figure 1, towards the viewer.

A spray gun 8 of the well known type, for spraying a heated thermoplastic material contained desired additives, is mounted at one end of a mounting plate 10 which, in turn, is mounted on a transverse member 1 2 which is pivoted by means of suitable plain pivotal joints 14 to the lower ends of two parallel swinging links 16, thus extending between the two links. The upper ends of the two links 1 6 are pivoted by means of similar plain pivotal joints 1 8 to respective lugs 20 (of which only the left hand one is shown) which are welded or otherwise fixed to the main chassis members 2. A further spray gun mounting plate 10 is shown at the right hand end of the transverse member 12, so that one or more spray guns can be mounted at that side of the machine, as well as or instead of the gun shown at the left.

It will be appreciated that such a support mechanism, comprising the swinging links 16, enables the transverse member 12 and hence the gun 8 carried on it to be swung in either direction from the position shown, and in the plane of Figure 1. In broken lines this whole assembly is shown swung to the left and it can be seen that the link constrains the gun to move along a path which has a vertical component, so that the gun is raised away from the ground, and also a horizontal component so that the gun is moved away from the centre line of the machine, these movements occurring simultaneously and the path in fact being of arcuate form.

It will be appreciated that this movement requires only a single adjusting operation to be carried out, but, in fact, we have found that this nevertheless enables most of the commonly required adjustments of line width, and line position relative to the centre line of the machine, to be dealt with without making any additional adjustments to the machine. To explain further, one common requirement is to spray a single relatively narrow stripe. To make the stripe narrow, the spray gun 8 should be relatively close to the ground. It should also be kept as close to the main body of the machine as possible because in the circumstances in which the machines operate it is undesirable and dangerous for the gun to project farther than is necessary from the machine.On the other hand, the spray gun 8 must not lie immediately ahead of the rear wheel 4 because if it does that wheel will roll on the freshly sprayed line and spoil it. Consequently, a suitable gun position for spraying a narrow line is just outside the rear wheel track of the machine, and relatively close to the ground as shown in Figure 1.

In order to spray a broader stripe or line, the gun needs to be further from the ground but, if its distance from the ground is increased while it -remains relatively close to the main body of the machine, the resulting increased distance and width of the spray makes it likely that sprayed material will start to impinge on parts of the machine. The support mechanism shown avoids this problem in a simple manner because in order to raise the gun it must be swung also to the left, consequently given greater clearance between the gun and the machine when spraying a broad stripe or line.

A further common requirement is to spray two stripes or lines which are parallel to each other, as is common between road carriageways running in opposite directions, and these lines also normally have to be broad. To achieve this with the machine which is shown, a second gun 8 would be provided on mounting 10, spaced inwardly from the gun 8 which is shown. This second gun can be switched off when spraying a single line but, when it is desired to spray two broad parallel lines the transverse member 12 is swung out to the broken line position, or perhaps a little further, and then both guns will be at a relatively large distance from the road, thus producing two broad lines, and both of them will be sufficiently far from the rear wheel 4 and the body of the machine to avoid fouling the machine and to avoid the wheel 4 running over the inner step sprayed stripe.

For the purpose of illustration, a narrow stripe 22 and a broad stripe 24 are shown in Figure 1, as produced by the gun 8 when in its full line position and in its broken line position, respectively.

Further details of the relevant part of the machine will now be described, referring to Figures 2 and 3 as well as to Figure 1.

The material to be sprayed, normally a hot thermoplastics material, is contained in a reservoir (not shown) mounted on the machine. It is taken from the reservoir by means of a pipe which need only be two or three inches long, to a pivotal joint 26 which is at a fixed location on the machine.

From that joint it flows into a conduit 28 which is within a central swinging link 30 which is parallel to the swinging link 1 6. From there is passes through a further pivotal joint 32 into a conduit 34 which is within the transverse member 12. From there, it is fed to the spray gun 8 as will be described later with reference to Figure 2. First, it will be explained how the material to be sprayed is heated throughout its passage from the joint 26 down to the spray gun 8.

The central swinging link 30 has a sealed outer casing 36 which forms, together with the central conduit 28, a space 38 surrounding the conduit 28, through which heated oil can be circulated from a heating system mounted on the machine in conventional manner, and coupled to the space 38 by suitable flexible tubes and inlet and outlet fittings (not shown); this enables the material to be sprayed to be heated as it travels from pivotal joint 26 to pivotal joint 32.

Joints 26 and 32 can be of the same construction and some detail of the joint 32 is shown in Figure 3. The joint 32 comprises a boss 40 which is welded to the outer casing 36 of link 30 with its central aperture in register with the open end of conduit 28. The boss 40 has an annular flange 42 around it and this flange is lightly clamped, by means of bolts 44, between a centrally apertured plate 46 and an annular clamping ring 48, both these latter components being relieved so as to be a close fit around the periphery of the boss 40. This arrangement allows link 30 to pivot relative to the fixed plate 46, while at the same time maintaining an adequate seal between the sliding surfaces.

Plate 46 is welded to one side of the hollow transverse member 1 2. The equivalent fixed plate of the other pivotal joint 26 is welded or otherwise secured to the end of the short pipe which carries the material to be sprayed, from the reservoir tank to the joint 26.

The conduit 34 is formed by a U-shaped channel having its open side welded to plate 10, and has a short branch 50 leading off it, the open end of this branch being welded to the periphery of an aperture 52 which is in register with the central aperture through the pivotal joint 32, so that the spray liquid can flow through the joint, through the branch 50 and into the conduit 34.

Having flowed along conduit 34 the liquid is then introduced to the spray gun by flowing through an aperture 56 in the spray gun mounting plate 10.

The liquid is received from aperture 56 by the spray gun 8, and sprayed under pressure, in conventional manner, the spray gun being supplied with compressed air For the purpose of forming the pressurized spray.

It will be understood that the conduit 34 lying within the transverse member 12 forms a closed space 60 between these elements, through which heated oil can be circulated by means of suitable flexible supply and return lines, and connections, so as to ensure that the liquid to be sprayed is kept heated as it travels from pivotal joint 32 out to the spray gun 8.

It can be seen from Figure 2 that the spray gun mounting plate 10 has chamfered upper and lower edges and the spray gun body is provided with a notch which fits over the upper edge and with a chamfered clamping element 62 which fits against the lower edge and which clamps the spray gun to the clamping plate in any given position when a clamping bolt 64 is tightened. In order to provide a variety of different positions for the spray gun along the clamping plate 10, a plurality of apertures 56 are provided and, when not in use, can be sealed by means of suitable plugs which, if necessary, can be threadedly mounted in the apertures.

The arrangement is supported in any selected position by, for example, a chain 66 whose lower end is coupled to an eye 68 on one of the links 16 and one of whose upper links is hooked on a hook 70 swivel-mounted on a screw 72 carrying an operating handwheel 74, the screw 72 being threadedly engaged in a plate 76 on chassis member 2. Coarse adjustment is obtained by selecting which chain link is hooked on hook 70 and fine adjustment by rotating handwheel 74 and thus screw 72. A similar arrangement may be provided at both sides so that the spray bar can be supported when swung to either side, or plate 76 may be removably fitted to chassis member 2 so the whole chain support arrangement can be transferred to the other side of the chassis when the spray bar is to be swung out to the right.

It should be appreciated that many variations on the detailed construction of the machine may be made, as compared with the particular example which has been described. Although in the described version the spray gun mounting moves in the plane which is transverse to the fore and aft axis of the machine, it may simultaneously or additionally be movable also in the fore and aft direction. It is envisaged that instead of employing two swinging links 1 6 in addition to the fluidconducting swinging link 30, the link 30 could serve in place of one of the swinging links 1 6. In fact, it is also feasible for the spray gun to be rigidly mounted at the end of a fluid-conducting link such as the link 30, and for the transverse member 12 to be dispensed with. This clearly gives less flexibility in positioning the spray gun and causes its spray to be angled relative to the road surface when the link is swung to one side, but may be acceptable in certain circumstances.

Of course, the system may be used, or adapted for use, with other sprayable materials than thermoplastics, such as hot and cold traffic paints, or epoxy or other two-component paints.

Claims (3)

1. A machine for spraying stripes on a substantially horizontal surface, the machine comprising ground engaging means on which it can be moved over the surface and comprising a mounting for a spray gun, which mounting is supported by a support mechanism which permits movement of the mounting but is operable to constrain such movement to a path having a component transverse to a fore and aft axis of the machine and a vertical component, whereby the mounting is movable simultaneously transversely and towards or away from said surface.

2. A machine as claimed in claim 1 wherein as the spray gun mounting is moved transversely away from the fore and aft axis of the machine its distance from said surface increases.

3. A machine as claimed in claim 2, wherein the wground-engaging means includes at least rear wheels, a downwardly directed spray gun is on said mounting ahead of said rear wheels, and is movable on said support mechanism along a path from a position closer to said surface and outside the rear wheel track to a position farther from said surface and farther outside said rear wheel track.

1 3. A machine as claimed in claim 12, comprising at least one downwardly directed 'spray gun mounted on each said mounting.

3. A machine as claimed in claim 2 wherein the ground-engaging means includes at least rear wheels, a spray gun is on said mounting ahead of said rear wheels, and is movable on said support mechanism along a path from a position closer to said surface and outside the rear wheel track to a position farther from said surface and farther outside said rear wheel track.

4. A machine as claimed in any one of claims 1 to 3 wherein the support mechanism comprises at least one swinging link pivoted to a fixed part of the machine and supporting the spray gun mounting.

5. A machine as claimed in claim 4 wherein the support mechanism comprises two swinging links each pivoted to fixed parts of the machine and spaced from each other transversely of the machine, the spray gun mounting being on a transverse member pivoted to both swinging links and extending between them.

6. A machine as claimed in claim 5 in which the, one of the, or a further, swinging link is a fluid-conducting link pivoted to a fixed part of the machine by means of a pivotal joint adapted to allow flow of fluid to be sprayed, through said joint, a reservoir for said fluid being located on the machine and being coupled to said joint and the swinging link including a conduit for conducting fluid from the joint to the spray gun.

7. A machine as claimed in claim 6 wherein the fiuid-conducting swinging link is also Divoted to the heating fluid, to enable heating of the fluid conduit therein.

8. A machine as claimed in claim 6 or claim 7 comprising one said fluid-conducting link and a respective non-fluid-conducting link located to each side of the fluid-conducting link.

9. A machine as claimed in any one of claims 6 to 8, when dependent on claim 5, wherein the fluid conducting swinging link is also pivoted to the transverse member by a pivotal joint adapted to allow fluid flow therethrough from the conduit in the link to a conduit of the transverse member.

10. A machine as claimed in claim 9 wherein the transverse member includes a jacket for heating fluid, to enable heating of the fluid conduit therein.

11. A machine as claimed in claim 9 or claim 10 wherein the conduit of the transverse member has a plurality of tapping points spaced along it and a spray gun is selectively connnectable to any one of the tapping points.

12. A machine as claimed in any one of claims 5 to 11 comprising a spray gun mounting at each end of the transverse member.

13. A machine as claimed in claim 1 2 comprising at least one spray gun mounted on each said mounting.

14. A machine for spraying stripes of different width on a horizontal surface, substantially as hereinbefore described with reference to the accompanying drawings.

New claims or amendments to claims filed on 24-8-79.

Superseded claims 1, 3, 13.

New or amended claims:

1. A machine for spraying stripes on a substantially horizontal surface, the machine comprising ground engaging means on which it can be moved over the surface and comprising a mounting for a spray gun, which mounting is supported by a support mechanism which permits movement of the mounting but is operable to constrain such movement to a path having a component transverse to a fore and aft axis of the machine and a vertical component, whereby the mounting is movable simultaneously transversely and towards or away from said surface, the support mechanism being adapted to keep the mounting in a substantially constant orientation as it moves along said path.