[0001] The present invention relates to a road reflector having a function for preventing
a road reflector from fogging which is liable to bring about at the time of a cold
season.
[0002] A road reflector is a safety device placed at positions where are obstructed to see
through, such as intersections, bending curves and the like, but the reflector is
fogged during the cold night and morning from autumn to spring and becomes not only
useless but also dangerous in traffic. Therefore, its solution has strongly been expected.
[0003] The main reason why a road reflector is fogged from the cold night to morning is
as follows.
[0004] That is, the temperature of a mirror surface more lowers than the dew point temperature
of ambient air by radiational cooling, and water drops are condensed on the mirror
surface or ice grains are adhered to the mirror surface. Therefore, in order to prevent
the road reflector from fogging, the mirror surface should be kept at higher temperature
than the ambient air temperature.
[0005] Japanese Utility Model Application Laid-open No. 61-19,890, as a prior art, is proposed
to form a latent heat regenerating layer between mirror surface plate and a back plate,
but the road reflector is placed at various places of the whole country, and a temperature
around the reflector is different by area. In order to exhibit a sufficient effect
at every temperature, it is effective to utilize a latent heat regenerator having
large heat regenerating energy.
[0006] Water has the largest regenerating amount. In case of a reflector, a regenerator
having 3-4 times the latent heat regeneration at a certain temperature but less than
half the water at the other temperature zone is not suitable for a reflector. Moreover,
it is a preferable method to form a regenerating layer between a surface mirror plate
and a back plate, but if heat insulation material is not provided on the back plate
side, heat is dissipated from the back plate direction and the heat dissipation increase
and no effect is almost caused.
[0007] Japanese Patent Application Laid-open No. 63-167,803 further proposes a method of
injecting an anti-freeze into a sealed vessel made between a mirror surface plate
and a back plate. The problems of this method are that a road reflector index by Japan
Highway Association provides for a stainless steel mirror plate of ∅600 mm diameter
in circle and 0.8 mm in thickness, ∅800 mm diameter in circle and 0.9 in thickness,
and ∅1000 mm diameter in circle and 1.0 mm in thickness, and that an image distortion
should be collated with a limit sample by the naked eye.
[0008] In the same manner as in Japanese Utility Model Application Laid-open No. 61-19,890,
the above proposal does not provide any heat insulation material on the back plate
side, heat dissipates from the back plate direction, and it has almost no effect.
This proposal is to inject an anti-freeze into the inside, but a mirror is ∅800 mm
in circle and an average space between the mirror surface and the back plate is 3
cm, 15 kg of an anti-freeze should be injected, so that it means to push the mirror
surface to the curved direction and lower direction so as to swell in the lower part
and it is not for use by distortion of an image.
[0009] Moreover, Japanese Patent application Laid-open No. 2-20,508 proposes to provide
a liquid regenerating agent-containing vessel on the mirror surface side between a
road reflector mirror plate and a back plate, to arrange heat insulation material
on the back plate side, to collect heat from the mirror surface within a time zone
of high air temperature in the daytime, to warm the mirror surface from the regenerating
agent when the air temperature is lowered from the night to early morning, and to
maintain a mirror surface temperature higher than the ambient air temperature.
[0010] The problem in this method is that a liquid regenerating agent is circulated by convection
when air temperature is increased from early morning, a temperature of the regenerating
agent is increased at the upper portion, but it is slowly increased at the lower portion.
[0011] Therefore, the temperature in the lower portion of the mirror plate is delayed to
increase because the temperature rise of the lower portion of the regenerating agent
is delayed even when the air temperature is increased, and in this period, the temperature
of the mirror plate is lower than the ambient air temperature to make the mirror surface
dim. Moreover, when the air temperature is lowered from the night to the early morning,
the regenerating agent within the inside is convected, the radiation of the regenerating
agent is accelerated, and the regenerating effect is lowered.
[0012] As described above, hitherto proposed techniques do not fully function in broad meteorological
condition.
[0013] The present invention aims to obviate said shortcoming by taking the above points
into consideration.
[0014] The present invention is to provide a road reflector having a sufficient anti-fogging
function from a lowering cycle to a rising cycle of temperature, since the main cause
of fogging a road reflector is because water in air is condensed on a mirror surface
when temperature of the mirror surface more lowers than the dew point temperature
of ambient air by radiational cooling.
[0015] An object of the present invention is to provide a road reflector with non-fogging
function comprising: a mirror plate, a back plate secured to said mirror plate in
the periphery of said mirror plate so as to make a sealed container, a heat insulating
material inserted to back side of said mirror plate within said container, characterized
in that a road reflector comprises a regenerating agent containing vessel attached
to the back side of said mirror plate within said container as being heat transferable,
a heat insulating material attached to back side of said vessel, thereby said road
reflector is united integrally with a mirror plate, a regenerating agent containing
vessel and heat insulating materials.
[0016] Another object of the present invention is to provide a road reflector wherein said
road reflector further comprises a heat buffer inserted and attached between the back
side of said mirror plate and said regenerating agent containing vessel.
[0017] Still another object of the present invention is to provide a road reflector wherein
said road reflector further comprises a roof plate attached to the upper portion of
said mirror plate, a supporting plate attached to the back side of the back plate,
a connecting piece pivotary connected to said supporting plate by a pivot, an elongated
groove and a positioning fitting so as to make positioning between said supporting
plate and said connecting piece, a clamp fitting for securing said connecting piece
to a column.
[0018] For a better understanding of the invention, reference is made to the accompanying,
in which:
Fig. 1 is a partially broken cross-sectional view by slicing the essential part showing
one embodiment of the present invention.
Fig. 2 is a partially broken perspective view showing one embodiment of a vessel containing
a regenerating agent.
Fig. 3 is a graph showing behaviors of temperature changes by comparing and measuring
performances of the road reflector (A) of the present invention and the prior products
(B) and (D).
Fig. 4 is a graph showing behaviors of temperature changes by comparing and measuring
performances of the road reflector (A) of the present invention and the prior products
(B) and (D).
[0019] Throughout different views of the drawing in Figs. 1-4, 1 is mirror plate, 1A is
mirror surface, 1B is rear surface of mirror, 2 is back plate, 3 is roof plate, 4
is regenerating agent containing-vessel, 5 is regenerating agent, 6A is heat insulation
material, 6B is heat insulation material, 7 is fastening portion for mirror surface
back plate, 8 is supporting plate, 9 is connecting piece, 10 is pivot, 11 is positioning
fittings, 12 is elongated groove, 13 is column, 14 is clamp fitment, 15 is uniform
liquid amount seal, 16 is outer peripheral seal, 16 is injection hole, and 18 is heat
buffer.
[0020] Present invention is more in detail explained with respect to Road Reflector with
non-fogging function.
[0021] A regenerating portion is the main portion of the present system, and as a regenerating
agent, use may be made of gel-like material which regenerates latent heat having uniform
specific heat within a wide temperature range.
[0022] That is, if the regenerating agent is gel-like, there is no convention, the regenerating
energy of the regenerating agent is effectively utilized for a long period of time,
there is no possibility of leaking, and there is shown a preferable tendency to vibration
during transportation. Moreover, it is possible to mold into desired curvature, and
it is also possible to integrate the molded article by fitting to a road reflector
by hand.
[0023] For the purpose of reducing manufacturing cost, such a method is possible that a
vessel which base is a mirror is formed and a liquid regenerating agent is gelled
therein.
[0024] As a vessel having less permeable loss, use is made of a three-layered film sandwiching
an aluminum foil with polyethylene films from both sides. In this case, it is preferable
to use a gel-like regenerating agent viewed from effective application of regenerating
energy and fear of liquid leakage.
[0025] A preferable regenerating agent has a large regenerating amount per volume through
all the area within a wide temperature range from -40°C to +40°C and does not freeze
at low temperature as possible, such as an aqueous solution of ethylene glycol, propylene
glycol, diethylene glycol and the like.
[0026] Any method can be used for gelling a regenerating agent. For example, there is a
method of gelling a regenerating agent with the use of a proper amount of high water
absorbing resin available on the market, or a method of adding 5-10 wt% of polyvinyl
alcohol available on the market, solving at high temperature, and freezing it, or
a method of adding a bifunctional monomer such as ethylene glycol, dimethacrylate
and the like to a water-soluble monomer such as hydroxyethyl methacrylate and the
like and carrying out a polymerization reaction. Any method can be used for gelling.
[0027] A heat insulation material, use is made of such material having independent air bubbles
and a role as a buffer, such as urethane foam and expanded styrol.
[0028] The present invention will be further explained in detail by referring to example.
[0029] Fig. 1 is a cross-sectional view of a road reflector according to the present invention.
Fig. 2 is a partly broken perspective view of a vessel for containing a regenerating
agent.
[0030] In Fig. 1, 1 is a metallic mirror plate having a mirror surface 1A of suitable curvature,
2 is an integrally joined back plate having a space for housing suitable contents,
and 3 is a roof projected from said mirror plate upwardly. In the present invention,
a heat buffer 18 is provided adjacent to the inner side of the mirror plate 1. Next,
a vessel 4 for containing a gel-like regenerating agent is housed by adhering to the
heat buffer 18, a gel-like regenerating agent 5 is filled within the vessel 4, heat
insulation material 6A is adhesively arranged on the rear of this regenerating agent-containing
vessel 4, and further heat insulation material 6B is arranged between the heat insulation
material 6A and the back plate 2, thereby preventing the surface of the reflector
1 from fogging by moisture condensation.
[0031] Reference numeral 7 is a fastening portion for integrally connecting the mirror plate
1 and the back plate 2. 8 is a supporting plate fitted to the rear of the back plate
2. 9 is a connecting piece, 10 is a pivot for pivoting the connecting piece 9 to the
supporting plate 8. 11 is a fittings for positioning between the supporting plate
8 and the connecting piece 9. 12 is an arc-like elongated groove for fitting the fittings
11. 13 is a column for supporting the connecting piece 9, and 14 is a clamp fitting
thereof. As a regenerating agent, it is preferable to use a gel-like regenerating
agent having a large regenerating amount per volume in the whole zone of a wide temperature
range from about -40°C to +40°C, without freezing at low temperature with no toxicity,
and being stable for a long period of time.
[0032] Moreover, compatibility of the regenerating agent with a vessel should fully taken
into consideration.
[0033] The present invention takes the above conditions into consideration, and in case
of using a mirror of 800 mm∅ in diameter for example, 2.5% high water absorbing resin
is added to a compounded solution of propylene glycol and water and injected into
the vessel 4 for use. The gel-like regenerating agent 5 is contained in the vessel
4 and fixed between the heat buffer 18 and the heat insulation material 6A. In case
of a road reflector of 800 mm∅, a suitable curvature radius of the mirror surface
is 3000 mm.
[0034] It is desirable to adhere the vessel 4 for containing the regenerating agent 5 to
the inside surface 1B of the mirror plate 1 via the heat buffer 18 with respect to
the curve of the mirror surface. It is also desirable to make regenerating agent volumes
per unit area of the center portion and the outer peripheral portion of the mirror
plate 1 substantially the same. Moreover, as explained above, a use temperature is
from -40°C to +40°C, so that it is necessary to prevent the vessel 4 from breaking
by volume expansion of the regenerating agent 5 and to prevent the regenerating agent
5 from dissipating to the outside.
[0035] Under consideration of these conditions, the present invention uses a round vessel
as the vessel 4 by using a three-layered film made by sandwiching an aluminum foil
with polyethylene film and a polyester film, but the vessel is not limited thereto.
The vessel 4 for containing a regenerating agent is composed of a film 2 with a uniform
liquid amount seal 15 and an outer peripheral seal 16 at certain intervals to control
a permeable loss for making the gel-like regenerating agent 5 substantially the same
volume over the whole mirror surface. The vessel 4 is provided with an injection hole
for injecting the regenerating agent 5.
[0036] Heat insulation materials 6A and 6B are inserted between the vessel 4 and the back
plate 2. The heat insulation materials 6A and 6B are made by laminating two sheets
of 40 mm thick × 800 mm∅ and 20 mm thick × 400 mm∅, putting in a polyethylene film
bag, and waterproofing. At a time zone of high air temperature during the daytime,
heat is collected from the mirror surface, transmitted to the regenerating agent 5
and regenerated. When the air temperature is lowered from the night to early morning,
the mirror surface 1A is warmed from the inside by dissipating heat only from the
side of the mirror plate 1, and the temperature is kept higher than the ambient air
temperature. Moreover, the regenerating agent is gelled so as to dissipate quantity
of regenerated heat by taking much time.
[0037] A sponge used as heat insulation material plays a role of a buffer by adhering the
vessel 4 to the inner surface 1B of the mirror surface with the aid of its resilience.
[0038] Fig. 3 shows a result of comparing the road reflector A of the present invention
with the prior road reflector B having a non-fogging device with the use of a liquid
regenerating agent on the back of a reflector.
[0039] As shown in Fig. 3, it shows records and graphs of ten day's observation for a mirror
surface temperature and its ambient temperature at 6:30 every morning in the wintertime,
that the mirror surface temperature (A) of the reflector of the present invention
is higher than the mirror surface temperature (B) of the reflector having no-fogging
function and higher than the ambient temperature (C) over the whole zone of an observation
period. The prior product (B) shows substantially the same temperature as the ambient
temperature (C).
[0040] Fig. 4 shows a result of comparing the road reflector of the present invention with
a road reflector having a non-fogging device of the system proposed by Japanese Patent
Application Laid-open No. 2-204,508, which is called a prior product (D) hereinafter.
[0041] Fig. 4 show records and graphs of the mirror surface temperature and its ambient
temperature of both the reflectors for 24 hours, and that the mirror surface temperature
of the reflector of the present invention shows a high temperature from the night
to 10 o'clock in the morning as compared with the prior product (D). This is because
the ambient temperature starts to lower from the evening, and regenerated temperature
energy released from the regenerating agent, which is gelled in the present invention,
continues its regenerating effect for long time. While, the prior product (D) which
mirror surface temperature is increased without any time lag with increase of the
ambient temperature from the morning cannot continue a regenerating effect by a convection
action because of the use of a liquid regenerating agent.
[0042] It shows from the above comparative test result that the reflector of the present
invention shows an extremely effective non-fogging effect.
[0043] The present invention relates to improvement of a road reflector provided at intersections
and hardly visible places, uses a gel-like regenerating agent as a regenerating agent,
and utilizes long regenerating time, so as to prevent the reflector from fogging generated
at the cold season and from the night to the early morning with high humidity and
to constantly perform a function of the road reflector, and has such a remarkable
effect that safety of traffic can be increased.
[0044] The prior road reflector has been tried to prevent fogging variously, but a non-fogging
effect is not sufficient, and hindered at the cold or humid season, but the present
invention solves the problem by such a simple mechanism that a heat buffer is inserted
in the inside of the mirror surface of the reflector, a soft vessel containing a gel-like
regenerating agent is adhered thereto, a heat insulation material is attached to the
back thereof and a back plate is heat-insulatingly buffered. As a result, fogging
by surface condensation of the mirror plate can be prevented as compared with the
use of an anti-freeze and liquid regenerating agent, heat is well conducting, and
the mirror surface is prevented from distorting, so as to remarkably increase its
effect and to be useful industrially.