Note: Descriptions are shown in the official language in which they were submitted.
TITLE
A ground surface marker and method for surface marking.
FIELD OF INVENTION
This invention relates to a ground surface marker and method for surface
marking. A
preferred form of the invention relates to a surface marker that uses paint
embedded
with glass beads where the paint is dried using UV light.
BACKGROUND
It is known to apply surface markings, for example road markings, using paint.
Many
current road marking paints have a touch dry time from about five minutes to
one hour,
with full drying taking 24 hours or more, depending on the air temperature.
The dry
time of current paints can delay the opening of a road which may be costly
because it
increases the need for traffic control, and can expose contractors to motoring
hazards.
If roads are opened prior to full drying of the paint then the road markings
may be
compromised by contact with vehicle wheels.
OBJECT OF THE INVENTION
It is an object of a preferred embodiment of the invention to go at least some
way
towards addressing at least some of these problems. While this applies to the
preferred embodiment, it should be understood that the object of the invention
per se is
simply to provide a useful choice. Therefore any objects or advantages
applicable to
any preferred embodiment should not be seen as a limitation on the scope of
claims
expressed more broadly.
INTERPRETATION
The term "comprises", or derivatives thereof, should not be interpreted as
excluding
other features. For example, if used in relation to a combination of features
it indicates
that optionally, but not necessarily, there may be additional features that
have not been
mentioned.
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SUMMARY OF THE INVENTION
In a first aspect of the invention there is provided a ground surface marker,
comprising:
= a paint applicator;
= a dispenser adapted to dispense reflectors; and
= an LED UV light source;
characterised in that the marker can move or be moved across a ground surface
so
that as it moves:
= the applicator applies resin paint to the surface;
= the dispenser causes the reflectors to contact the paint so that at least
some are partially embedded in the paint and some are fully embedded in
the paint, at least some of the partially embedded reflectors contacting
some of the fully embedded reflectors;
= the LED light source applies UV light to the paint and reflectors so that
the
UV light refracts through the reflectors and into the paint to dry the paint
so
that the reflectors are fixed in the paint and are able to reflect visible
light.
Optionally the reflectors are of a type that allow at least a substantial
portion of the UV
light to pass through them to facilitate drying of the paint from within the
paint (eg
drying from below the upper surface of the paint).
Optionally the UV light has a wavelength in the range of about 365 to 430
nanometres.
Optionally the UV light has a wavelength in the range of about 345 to 410
nanometres.
Optionally the UV light has a wavelength of about 405 nanometres.
Optionally the UV light source incorporates a housing and a fringe of
bristles, the
bristles arranged to keep light from the UV light source substantially within
the fringe.
Optionally the surface marker comprises a pair of paint guides (eg chains or
other
threads), each guide extending vertically so that there is a space between
them, the
guides being aligned with the applicator to guide straight line application of
paint on a
ground surface.
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Optionally the reflectors comprise glass beads.
Optionally the reflectors comprise quartz beads.
Optionally the beads are generally spherical with an average diameter of from
about
100 microns to about 850 microns in diameter.
Optionally the beads are generally spherical with an average diameter of about
850
microns to about 1400 microns in diameter.
Optionally the paint applicator is arranged to spray the paint.
Optionally the marker is loaded with paint and is suitable for applying that
paint to a
ground surface to have film thickness of about 175 to about 350 microns when
dry.
Optionally the marker is loaded with paint and is suitable for applying that
paint to a
ground surface to have film thickness of about 175 to about 300 microns when
dry.
Optionally the marker is loaded with paint and is suitable for applying that
paint to a
ground surface to have film thickness of about 175 to about 250 microns when
dry.
Optionally the ground surface marker comprises:
= a motorised wheeled vehicle;
= a paint sprayer connected by a hose to a paint tank;
= the UV light source comprising a housing and a fringe of bristles; and
= a pair of paint guides, each guide extending vertically so that there is
a space
between them, the guides being aligned with the applicator;
characterised in that the marker can move or be moved across a ground surface
by a human operator so that as it moves:
= the sprayer sprays paint from the tank to the surface in a line at least
partially between the guides;
= the dispenser causes the reflectors to move to contact the paint; and
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= the UV light source applies UV light to the paint and reflectors to dry
the
paint so that the reflectors are fixed in the paint and able to reflect
visible
light, the bristles keeping light from the UV light source substantially
within
the fringe.
According to a further aspect of the invention there is provided a method of
marking a
ground surface comprising the steps of:
= moving along the surface a ground surface marker comprising a paint
applicator, a dispenser associated with reflectors and a UV light source;
= applying paint to the surface;
= causing reflectors to sit in the paint on the surface; and
= applying UV light to the paint and reflectors such that the light causes
the paint
to dry such that the reflectors are fixed in the paint and able to reflect
visible
light.
Optionally the reflectors are allow at least a substantial portion of the UV
light to pass
through them to facilitate drying of the paint from within the paint beneath
the upper
surface of the paint.
Optionally the UV light has a frequency in the range of about 365 to 430
nanometres.
Optionally the UV light has a frequency in the range of about 345 to 410
nanometres.
Optionally the UV light has a frequency of about 405 nanometres.
Optionally the UV light source incorporates a housing and a fringe of
bristles, the
bristles serving to keep light from the UV light source substantially within
the fringe.
Optionally the surface marker comprises a pair of paint guides (eg chains or
other
threads), each guide extending vertically so that there is a space between
them, the
guides being aligned with the applicator and used to guide straight-line
application of
the paint on the ground surface.
Optionally the reflectors comprise glass beads.
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Optionally the reflectors comprise quartz beads.
Optionally the beads are spherical and have an average diameter from about 100
microns to about 850 microns in diameter.
Optionally the beads are spherical and have an average diameter from about 850
microns to about 1400 microns in diameter.
Optionally the paint applicator sprays the paint on the surface.
Optionally the marker applies the paint to the ground surface to have film
thickness of
about 175 to about 300 microns when dry.
Optionally the marker applies the paint to the ground surface to have film
thickness of
about 175 to about 250 microns when dry.
Optionally the marker applies the paint to the ground surface to have film
thickness of
about 175 to about 200 microns when dry.
BRIEF DESCRIPTION OF DRAWINGS
Some preferred embodiments of the invention will now be described by way of
example and with reference to the accompanying drawings and images, of which:
Figure 1 is a front perspective view of a ground surface marker;
Figure 2 is a rear side perspective view of part of the marker;
Figure 3 is a front side perspective view of part of the marker; and
Figure 4 is a further perspective view of part of the marker.
Figure 5 is a diagrammatic view of UV light passing through beads in
paint.
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DETAILED DESCRIPTION
Referring to figures 1-4 a ground surface marker 1 comprises a paint tank 2, a
bead
container 3, a pump (not shown), a generator 4, a paint applicator, for
example a spray
gun 5, a bead dispenser 6, and a UV light module 7. The marker 1 is typically
used to
apply paint to a road to either create new road markings or to repaint
existing road
markings that are fading. The marker 1 may also be used for surfaces in off-
road
situations, for example for applying markings in carparks, schools, shopping
centres,
factories, and warehouses.
In the preferred embodiment shown in figure 1 the marker 1 comprises a three
or four-
wheeled motorised cart driven by a human operator 8. However, in alternative
embodiments the marker 1 may comprise a larger vehicle, for example a truck,
which
may accommodate multiple operators. In still further embodiments the marker 1
may
be towed and without its own motive force or may be automated.
A paint hose 9 connects the paint tank 2 to the spray gun 5. The hose 9 is
preferably
high pressure, polytetrafluoroethylene ("PTFE")/TeflonTm- lined, and light-
shielded. The
pump is a low shear, high pressure pump capable of delivering paint from the
tank 2 to
the spray gun 5 within a range of 1-3000 pounds per square inch ("PSI"). The
spray
gun 5 is preferably an automatic, airless spray gun with PTFE/Teflon TM low
sheer
seals. However other types of spray gun are also suitable, for example an air-
pressurised spray gun. The pump is able to deliver paint from the tank 2 to
and from
the spray gun 5.
A bead hose 10 connects the bead container 3 to the dispenser 6. The container
3 is
filled with reflectors in the form of beads. The beads may be conventional
glass beads.
In an alternative embodiment of the invention the beads may be quartz beads.
Beads
will be substantially round and sized in the range of about 100 to 1400
microns in
diameter. In the preferred embodiment the beads will be in the range of about
600 to
850 microns (called Type B beads), and in the range of about 1100 to 1400
microns in
diameter (called Type D beads).
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The beads can be fed to the dispenser 6 by a pressure feeder (not shown).
Alternatively, the beads can be moved to the dispenser 6 under gravity.
The UV light module 7 comprises a housing 11 which contains an LED UV light
which
is powered by the generator 4. Alternatively a non-LED UV light may be used.
The
module 7 is attached to a metal frame 12 which forms part of the marker 1. The
lower
part of the housing 11 is open and surrounded by a fringe of coarse bristles
13 which
assists in protecting the eyesight of people in the vicinity of the marker 1
by
substantially blocking UV light from view. The bristles 13 are similar to
those used in
commercial and automotive dust, spray and light barriers.
As can be seen in figures 1 and 3, the marker 1 may also have a substantially
L-
shaped pole 14 that extends from the front of the marker 1. Fixed to the end
of the
pole is a pair of pair of guiding arms 15 from which chains 16 hang, to assist
the
operator to apply road markings in the correct position. To do this, the
operator 8 aligns
the marker 1 so that the chains 16 hang over either side of worn pre-existing
markings
as a visual cue for the operator 8. The spray gun 5 is arranged to deliver
paint
accurately when the chains 16 hang either side of pre-existing markings. If
new
markings are being painted, then the operator 8 aligns the marker 1 so that
the guide
chains 16 hang over either side of a guide line indicating where new road
markings
should be painted.
In use, the container 3 is filled with beads and the tank 2 is filled with
suitable paint. In
the preferred embodiment filled, thick film resin road marking paint is used.
The road
marking paint comprises synthetic resin, pigments, and packing
materials/particles.
Other types of paint may also be suitable for use in the invention, for
example water-
based paints, latex paints and acetone paints. White pigments in these paints
may
comprise titanium dioxide, zinc oxide, and lithophone. Yellow pigments in
these paints
may comprise heat-resistant yellow lead.
In the preferred embodiment, to apply or to reapply road markings the marker 1
is
driven by the operator to the correct position on the road. The operator
determines the
correct position by aligning the marker 1 and the chains 16 to hang as visual
cues, as
described above.
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The operator drives forward and activates the pump, spray gun 5, bead
dispenser 6
and the generator 4 to power the UV light module 7. The pump feeds paint to
the spray
gun 5. As can be seen in figures 1-4, the spray gun 5 applies paint to the
road. In the
preferred embodiment the paint is applied as a medium film build of about 175-
300
micron dry film thickness ("DFT"). Alternatively the film build can be in the
range of
about 175-250 micron DFT or about 175-200 micron DFT. However, the paint may
also
be applied as a high film build of up to about 350 micron DFT. The DFT may be
adjusted by the size of the spray tip and by the speed that the paint is
applied. Type D
beads are preferred for use with paint applied as a medium film build. Type B
beads, or
Type B beads mixed with Type D beads, are preferred for use with paint applied
as a
high film thickness.
At the same time beads are fed to the dispenser 6, which is positioned behind
the
spray gun 5, and the beads are sprayed onto the road and are fully or
partially
embedded into wet paint as the marker 1 moves forward. The UV light module 7,
powered by the generator 4, then passes over the bead-embedded paint and
causes
drying of the paint with embedded beads normally within about 0.5 to 1.5
seconds.
In an alternative embodiment of the invention, there are two bead containers
feeding
beads of alternative sizes to two corresponding bead dispensers. The two bead
dispensers are mounted one behind the other, dispensing larger beads (for
example,
Type D beads) first followed by smaller beads (for example, Type B beads)
after which
the UV light causes drying of the paint with embedded beads of different
sizes.
More specifically and referring to figure 5, the majority of the beads 17 are
partially
embedded in the paint 18 while some of the beads are fully embedded. The fully
embedded beads will typically be contacting or adjacent the partially embedded
beads.
UV light waves 19 pass through the partially embedded beads because they
protrude
from the paint and so are exposed to the UV light. UV light waves will also
pass
through embedded beads that are contacting the partially embedded beads. The
UV
light refracts through the beads and into the paint to dry it. The spherical
shape of the
beads assists in the refraction of the UV light. This drying is facilitated by
the
wavelength of the UV light. In the preferred embodiment of the invention the
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wavelength of the UV light is about 405 nanometres ("nm"). However, ranges of
about
365 to 430 nm and of about 345 to 410 nm are also effective. The process above
using UV light causes the paint to dry through the film within about 0.5 to
1.5 seconds
rather than only from the top down which is what happens when paint dries in
sunlight.
Using the marker 1 to dry paint means that the area painted does not need to
be
closed off to allow for drying for as long as with many conventional road
marking
methods. The operator may also reverse over lines already painted almost
immediately
without smudging the paint so that multiple lines that need to be painted or
repainted in
a small area can be done without having to wait long periods for paint to dry.
While some preferred embodiments of the invention have been described by way
of
example it should be appreciated that modifications and improvements can occur
without departing from the scope of the following claims.
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