GB2241270A

GB2241270A - Apparatus for applying preformed ribs of a thermoplastics material to a line marking on a road surface

Info

Publication number: GB2241270A
Application number: GB9101086A
Authority: GB
Inventors: Brian Ashley; John William Barnes
Original assignee: ASSOCIATED ASPHALT CO Ltd
Current assignee: ASSOCIATED ASPHALT CO Ltd
Priority date: 1990-01-19
Filing date: 1991-01-17
Publication date: 1991-08-28
Also published as: GB9001283D0; GB9101086D0

Abstract

Apparatus (10) for applying a preformed pad of a thermoplastics material to a line marking (11) on a road surface comprises a roller (12) which can be rolled along the line marking. The roller is provided with at least one recess (14a-14d) to receive the ribs individually and to transport each of the ribs individually to the line marking thereby to deposit the ribs on the line marking at spaced locations. Heating means (24) may be provided to soften the line marking before the ribs are applied thereto. <IMAGE>

Description

APPARATUS FOR APPLYING PREFORMED RIBS OF A TRERMOPLASTICS MATERIAL TO A LINE MARKING ON A ROAD SURFACE This invention relates to apparatus for applying preformed ribs of a thermoplastics material to a line marking on a road surface.

Line markings, e.g. white lines, on motorways and other roads are frequently formed of a thermoplastics material which is applied to the road surface in a thermoplastic state so that it welds and bonds to the road surface on cooling.

It is often desirable to provide ribbed line markings on motorways, for example, between the inside of left hand lane and the hard shoulder, the ribs being spaced 250 mm or 500 mm apart. The ribs serve to cause vibration and noise when a vehicle tyre runs along or crosses the line marking and thus alert drivers who inadvertently cross the line due to sleep or inattention One method of laying these ribs involves forming the ribs as the line marking is applied to the road surface.

It is an object of the invention to provide improved apparatus for applying preformed ribs of a thermoplastics material on an existing thermoplastics line marking on a road surface.

According to this invention there is provided apparatus suitable for applying preformed ribs of a thermoplastics material to a line marking on a road surface, said apparatus comprising a roller which can be rolled along said line marking, the roller being provided with at least one recess to receive said ribs individually and to transport said ribs individually to the line marking thereby to deposit the ribs on the line marking at spaced locations.

Preferably, the apparatus comprises a plurality of said recesses substantially evenly spaced about the circumference of the roller, each recess being adapted to receive an individual one of said ribs for transportation to the line marking.

The apparatus may comprise bonding means for providing a bonding interface between each pad and the line member to enable the pad to bond thereto. The bonding means may comprise heating means arranged in fixed relationship to said roller to apply heat to said line marking at locations where a pad is to be deposited.

Preferably, the heating means comprises a preheater and a heater, the preheater being arranged to apply heat to said locations before the heater applies heat thereto.

The apparatus may comprise heat actuation means and at least one formation on the roller adapted to cooperate with the heat actuation means on each rotation of the roller to cause the heating means to apply heat at said locations.

The heating means may be powered by gas and the heat actuation means may comprise a valve and a cam whereby the or each formation engages the cam on each rotation of the roller to cause the cam to open the valve to increase the flow of gas therethrough to apply heat to said locations, the heating in this case being by flame. However, gaspowered radiant heating can be employed, in which the supply of gas need not be variable so that the cam or other actuation process can be dispensed with.

The apparatus may comprise a hopper to hold a plurality of said ribs, the hopper being adapted to deliver the ribs individually into the or each recess for transportation to said line marking.

A curved member may be disposed in register with the roller to maintain said ribs in the or each recess until the ribs can be deposited on the line marking.

The apparatus may be self-propelled and embodying clutch means to control the operation of the apparatus.

Reference is now made to the accompanying drawing which is a schematic side view of apparatus according to the invention and which is given by way of example.

In the drawing, apparatus 10 is shown for applying preformed ribs of a thermoplastics material to a line marking 11, e.g. a white line, on a road surface.

The apparatus 10 is self-propelled and comprises a roller 12 having formed therein a plurality of evenly spaced recesses 14a, 14b, 14c and 14d about the outer surface of the roller 12. In the embodiment shown in the drawing, four recesses are shown, but it will be appreciated that any suitable number of recesses can be provided.

The apparatus 10 is designed to be moved along the line marking 11 in the direction of the arrow A. The apparatus 10 is provided with a handle 16 to enable the operator to control its speed and steering. A lever 18 is provided on the handle which is connected to a clutch (not shown)to control the drive from a motor (also not shown) provided to propel or drive the apparatus 10.

The apparatus 10 comprises a holder 20 to hold a plurality of ribs stacked one on top of the other. As the apparatus 10 is moved in the direction of arrow A, the roller will rotate in the direction of arrow B. This enables the holder 20 to deliver into each recess 14 an individual rib as each recess 14 passes under the holder 20. In the embodiment shown, the recess 14b is disposed under the holder 20 and is in position to receive a rib.

The roller 12 is mounted for rotation on a chassis 22.

Also mounted on the chassis 22 is a heating means 24 comprising a preheater 26 and a heater 28. The preheater 26 is spaced from the heater 28 by a distance which is substantially equal to the distance between the heater 28 and the point X. The point X is the point where a line perpendicular to the line marking 11 passes through the hub 30 of the roller 12. The point x is also the point where each recess 14 deposits onto the line marking 11 the rib which was recessed therein. In the embodiment shown, the recess 14d is in the position to deposit its rib onto the line marking 11.

The recesses 14 are evenly spaced about the roller 12 by a distance which is substantially equal to the distance between the heater 28 and the point X and the distance between the preheater 26 and the heater 28.

The preheater 26 and the heater 28 are connected to each other via a manifold 32, which is, in turn, connected to a gas cylinder 34 via a pipe 36. Disposed in the pipe 36 is a valve 38 which is controllable by operation of a cam 40.

Adjacent ends of the recesses 14a, 14b, 14c and 14d there is respectively a formation 42a, 42b, 42c and 42d, as shown in the drawing. Each of the formations is in the form of pegs projecting from the roller 12 such that each can cooperate with the cam 40.

As the apparatus 10 is moved in the direction of arrow A, and the roller 12 rotates in the direction of arrow B each formation 42a-42d will pass the position which the formation 42c occupies in the drawing. As each formation 42a-42d passes this position it will engage the cam 40 causing the valve 38 to be opened thereby allowing the flow of gas to the heating means to be increased. Thus, as each formation 42a-42d engages the cam 40 the preheater 26 and the heater 28 apply heat to the line marking 11 to soften it. As soon as the formations 42a-42d have passed the cam 40, the valve 38 is closed thus reducing the flow of gas to the heating means 24. With this arrangement, the heating of the line markings 11 is by gas flame, with the flame size increased when actual heating is required so as to conserve gas.

It will be appreciated therefore, that since the distance between the preheater and the heater is substantially the same as the distance between the heater and the point X which is, in turn, substantially the same as the spacing between the recesses on the roller, the heating means 24 only applies heat to the locations on the line marking 11 where a pad is to be applied by the apparatus 10.

In order to provide support for the apparatus 10 at the end thereof remote from the roller 12 a caster wheel 44 is provided.

The operation of the apparatus 10 will now be described. The holder 20 is filled with ribs and the gas from the cylinder 34 is turned on to supply gas to the preheater 26 and the heater 28 which is ignited. The apparatus 10 is then moved along the line marking 11 and as one of the recesses 14b passes under the holder 20 a rib is delivered into the recess 14b. At the same time the formation 42c engages sthe cam 40 causing the valve 38 to open. This causes the preheater 26 and the heater 28 to apply heat to the line marking Il to soften it at the locations directly under the preheater 26 and the heater 28.

As the apparatus 10 is moved further along, a rib is received in the next recess 14 and as the formation 42b engages the cam 40 the preheater 26 and the heater 28 apply heat to the line marking 11. As the recess 14b reaches the bottom of the roller 12, the recess 14b is directly over a location heated by the heating means 24 and the rib received therein is deposited onto the softened area of the line marking 11. This process is then repeated as the apparatus 10 is moved along the line marking 11 until a desired number of ribs have been applied to the line marking. It will be appreciated that ambient conditions will affect the operation of the apperatus from a temporal standpoint so that it may be necessary for the operator to introduce a dwell period during the actual heating mode of the apparatus.The operator will, by trial and error, establish the required dwell time necessary to heat the line marking to the required temperature and then control the apparatus accordingly, using the clutch control lever 18. A dwell time of the order of 5 or 6 seconds may be required in cold conditions, with this reducing in warm conditions.

As the heated locations of the line marking 11 cool they harden so that the rib deposited thereon is bonded thereto. As each rib is deposited onto the line marking 11, the weight of the roller 12 presses the rib onto the line marking 11.

A curved member 50 is provided adjacent the roller 12.

The curved member 50 is arranged relative to the roller 12 as shown in the drawing so that the ribs in the recesses 14 are prevented from falling out by the member 50.

The flame heating described above may be replaced by radiant heating which is conveniently gas-powered. This arrangement has been found to be preferable over flame heating in minimizing the dwell time and it also dispenses with the need for heat actuation means, such as the cam 40 and associated formations 42a, 42b, 42c and 42d. A mesh, for example a wire gauze, is heated to provide the required radiant heat and the gas supply is maintained substantially constant as the mesh needs to be maintained at the optimum temperature in order to minimise, in operation of the apparatus, the dwell time and hence increase the rate of rib laying.

Preferred ribs suitable for use with this invention are formed of a first layer of a thermoplastics material and a second layer of a reflective material. The thermo-plastics material is referred to as British Standard Material BS3262 and includes titanium dioxide to render it of a white colouration. It also includes aggregate to improve its abrasion resistance.

The second layer of the reflective material is in the form of a plurality of hemispheres of substantially 4 mm diameter attached together such that the curved surface of the spheres face away from the first layer. The hemispheres are preferably formed of glass or a clear plastics material.

Claims

1. Apparatus suitable for applying preformed ribs of a thermoplastics material to a line marking on a road surface, said apparatus comprising a roller which in the use of the apparatus can be rolled along said line marking, the roller being provided with at least one recess to receive said ribs individually and to transport each of said ribs individually to the line marking thereby to deposit the ribs on the line marking at spaced locations.

2. Apparatus according to Claim 1 comprising a plurality of recesses substantially evenly spaced about the circumference of the roller, each recess being adapted to receive an individual one of said ribs for transportation to the line marking.

3. Apparatus according to Claim 1 or 2 comprising bonding means to provide a bonding interface between each pad and the line marker to enable the pad to bond thereto.

4. Apparatus according to Claim 3 wherein the bonding means comprises heating means arranged in fixed relationship to said roller to apply heat to said line marking at locations where a pad is to be deposited.

5. Apparatus according to Claim 4 wherein the heating means comprises a preheater and a heater, the preheater being arranged to apply heat to said locations before said heater applies heat thereto.

6. Apparatus according to Claim 4 or 5 comprising heat actuation means and at least one formation adapted to cooperate with the heat actuation means on each rotation of the roller to control the application of heat to said locations.

7. Apparatus according to Claim 6 wherein the heating means are powered by gas and the heat actuation means comprises a valve and a cam, whereby the or each formation can engage the cam once on each rotation of the roller such that when said cam is engaged by the or each formation, the cam causes said valve to open to increase the flow of gas therethrough.

8. Apparatus according to any of Claims 1 to 5, wherein the heating means are of the radiant type.

9. Apparatus according to Claim 8, wherein the heating means are gas-powered.

10. Apparatus according to any of the preceding claims, wherein the apparatus is self-propelled and comprises clutch means to control the operation of the apparatus.

11. Apparatus according to any preceding claim comprising a holder to hold a plurality of said ribs, said holder being adapted to deliver said ribs individually into the or each recess for transportation to said line marking.

12. Apparatus according to any preceding claim comprising a curved member disposed in register with said roller to maintain said ribs in the or each recess until the ribs can be deposited on the line marking.

13. A preformed pad to be applied to a line marking on a road surface, said pad comprising a first layer of a thermoplastics material and a second layer of a reflective material.

14. Apparatus for applying preformed ribs of a thermoplastic material to a line marking on a road surface substantially as herein particularly described with reference to the accompanying drawings.