Road structure – process – or apparatus – Traffic director
Reexamination Certificate
1998-06-08
2001-08-21
Shackelford, H. (Department: 3671)
Road structure, process, or apparatus
Traffic director
C047S025100, C040S606040, C256S001000
Reexamination Certificate
active
06276869
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a weed control plate capable of effectively preventing the propagation of weeds germinating at the roots of supports of guardrails or the like.
Guardrails are installed in such places as the boundary between a roadway and a sidewalk, the boundary between a roadway and a road shoulder, the boundary between a road and a slope face, and a median strip in a road. Weeds are likely to grow thick around the guardrails. The reason for this is that the seeds of weeds enter gaps produced around the supports of the guardrails which are driven into the ground even if the sidewalk, the roadway, the slope face and the median strip are paved, not to mention the unpaved ground, and the weeds take root into the gaps.
When cutting the weeds having luxuriated around the roots of the guardrail supports by using an automatic mower, it is necessary to take care not to touch the supports. Therefore, the weed cutting operation is considerably troublesome because of the presence of the obstructive supports. If the rotating cutting blade of the automatic mower touches a support, the cutting blade may break and injure the operator. On the other hand, it takes heavy labor to cut the weeds around the roots of the supports by a manual operation using a sickle or the like.
Under the above-described circumstances, it has heretofore been proposed to install, as shown in
FIGS. 9 and 10
, a weed control plate
200
or
250
at the root of each support of a guardrail.
More specifically, the weed control plate
200
shown in
FIG. 9
has a cylindrical portion
201
and a flange portion
203
provided at the bottom of the cylindrical portion
201
. The weed control plate
250
shown in
FIG. 10
has a conical shape close to a flat plate. It is deemed that the propagation of weeds around the root of a support
300
can be suppressed to a certain extent by the weed control plate
200
or
250
.
However, the conventional weed control plates
200
and
250
suffer from some problems as stated below.
(1) The weed control plate
200
shown in
FIG. 9
is vertically split into two separate members to install it on the support
300
. The two members of the weed control plate
200
are installed to clamp the support
300
from the right and left sides, and the cut edges of the two members are joined together. In this state, the joint portions are secured by a predetermined securing device, thereby installing the weed control plate
200
.
However, the operation of installing the weed control plate
200
on the support
300
by joining together the two members is troublesome because it is necessary to align the two members with each other. In addition, the weed control plate
200
needs to secure the two vertically split members at two joint portions. The presence of two securing portions makes it likely that the clamping force with which the two members clamp the support
300
will weaken with time owing, for example, to expansion and contraction due to solar heat and vibrations caused by the passage of vehicles. If the clamping force weakens, the weed control plate
200
undesirably comes off the ground to become unable to fulfill its purpose.
(2) The weed control plate
250
shown in
FIG. 10
is cut from the outer periphery to the inner periphery thereof along a single cutting line, and the weed control plate
250
is installed onto the support
300
by opening the cut portion of the plate
250
. Thereafter, two edge portions of the plate
250
which are divided by the cutting line are overlaid on one another, and the overlaid portions are nailed on the ground, thereby installing the weed control plate
250
.
However, nailing cannot provide very high strength for securing the weed control plate
250
to the ground. Therefore, the weed control plate
250
is likely to separate from the support
300
and fly away in a storm, e.g. a typhoon.
Even in the case of the asphalt ground, not to mention the unpaved ground, the strength with which the weed control plate
250
is secured to the ground by nails may be weakened, for example, by solar heat, vibrations caused by the passage of vehicles, or people's stepping on the plate
250
. Accordingly, it is difficult for the weed control plate
250
to continue clamping the support
300
firmly for a long period of time. If the clamping force weakens, the weed control plate
250
undesirably comes off the ground to become unable to fulfill its purpose.
In a case where the weed control plate
250
is formed from a molding resin, the resin plate
250
may be deformed by solar heat. If the weed control plate
250
is deformed, the outer peripheral portion
253
of the weed control plate
250
may be bent to turn upward, and weeds may enter through the bent portion
253
.
Although it is conical, the weed control plate
250
has an unfavorably weak strength because the slope angle of the conical surface is exceedingly small. Therefore, the weed control plate
250
may be readily broken if a heavy object, e.g. a vehicle, gets on it.
(3) The conventional weed control plates
200
and
250
are arranged such that the bottom surface of each plate is exactly perpendicular to the direction in which the support
300
stands. Therefore, if the support
300
does not stand perpendicular to the ground, the bottom of the weed control plate
200
or
250
cannot come into close contact with the ground but slopes at an angle to it, resulting in a gap. In such a case, the propagation of weeds cannot effectively be prevented. In a case where the ground is uneven, the bottom of the weed control plate
200
or
250
cannot come into close contact with the ground, resulting in a gap. In such a case also, the propagation of weeds cannot effectively be prevented.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a weed control plate which can be readily installed on a support with a strong support clamping force without the likelihood of the outer peripheral portion thereof turning up regardless of the slope or unevenness of the ground.
The present invention is applicable to a weed control plate installed at the root of one of supports of various kinds so as to cover the ground around the root to prevent the propagation of weeds. According to the present invention, the weed control plate is a thin plate having a conical surface. The plate is provided in the center thereof with an opening for passing the support. The plate has a single parting line extending from the outer periphery to the inner periphery of the plate. Two edges of the plate which are divided by the parting line are fastened so as to join together with clamping members, thereby firmly fastening the inner peripheral surface of the opening to the outer periphery of the support.
According to the present invention, arranged as stated above, the weed control plate can be installed on the support simply by firmly fastening together the two edges of the plate divided by the parting line, which is provided in a single portion of the plate, directly with clamping members. Therefore, the installation operation is easy, and the clamping force with which the weed control plate clamps the support is strong and will not weaken with passage of time. Even if expansion and contraction of the weed control plate due to solar heat or vibrations caused by the passage of vehicles occur continuously, there is no likelihood of the weed control plate coming off the ground.
Further, the weed control plate is a thin conical plate, and there is a space under the weed control plate. Therefore, even if the ground is uneven, the outer peripheral edge of the plate can be readily brought into close contact with the ground.
It is preferable that the conical surface of the weed control plate should be curved convexly upward toward radially inward of the plate.
If the conical surface of the weed control plate is formed into such a curved surface, the conical surface has an arched shape as a whole. Therefore, even if a heavy object such as a bicycle gets on the conical surfa
Armstrong Westerman Hattori McLeland & Naughton LLP
Markovich Kristine M.
Shackelford H.
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