Hydraulic and earth engineering – Fluid control – treatment – or containment – Flow control
Reexamination Certificate
1999-02-18
2001-04-24
Lillis, Eileen D. (Department: 3673)
Hydraulic and earth engineering
Fluid control, treatment, or containment
Flow control
C405S119000, C405S121000, C405S123000, C249S010000, C249S011000, C404S002000, C404S003000
Reexamination Certificate
active
06220784
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the construction industry and more specifically to apparatus used in constructing grate-covered trenches.
BACKGROUND OF THE INVENTION
The use of concrete lined, grate or solid covered trenches are well known in the road, parking lot, and manufacturing plant construction industry. The typical trench construction includes a pair of spaced rails, wherein each rail has a grate supporting surface upon which a central grate rests.
FIGS. 1 and 2
illustrate a typical prior art trench-forming assembly
10
. Each rail
12
,
14
is made of a rigid material which preferably can be easily and inexpensively molded, cast, extruded, or stamped into a desired rail shape. As indicated in these figures, each rail
12
,
14
can be Z-shaped in cross-section and connected by a connecting rod
16
which typically is attached to the rails by welding to an inside surface
17
of each rail. When such connecting rods
16
are used, at least two such connecting rods are placed between each set of rails, typically with one rod positioned at the end of each rod pair. The connecting rods
16
are used to maintain the rails
12
,
14
in a fixed position relative to each other prior to and during the curing of the hardenable material used to form the completed trench.
Adjustable anchoring means typically are used to adjust the slope and height of the rails
12
,
14
. As indicated in
FIGS. 1 and 2
, one such means includes a connecting member
18
that extends outwardly from an outside surface
20
of the rails
12
,
14
to connect to an anchor rod
22
that is adapted to be driven into the ground at the bottom of the excavated trench. As is further indicated in the figures, the connecting member
18
includes a collar
24
through which the rod
22
can be passed. Each collar
24
includes a fastening member such as a thumb screw
26
which is threadingly inserted into an aperture formed within each collar so that, when the fastening member is tightened, the connecting member
18
can be fixed relative to the rod
22
such that the rails
12
,
14
can be supported by the rods in the desired position.
The prior art assembly
10
of
FIGS. 1 and 2
further includes a form
28
. Although capable of alternative construction, the form
28
typically is made of an expanded polystyrene foam which is adapted to be held in a fixed position between the rails
12
,
14
. The form
142
normally includes an upper surface
30
and a shaped lower surface
32
. The lower surface
32
can be shaped into any contour, but preferably is tapered from the upper surface
30
to facilitate simple removal from the final trench. In the embodiment illustrated in
FIGS. 1 and 2
, a plurality of grooves
34
are formed in the upper surface
30
of the form
28
to receive each connecting rod
16
provided along the rails
12
,
14
. The grooves
34
allow each connecting rod
16
to laterally traverse the form
28
to secure the form
28
in position while held between the rails
12
,
14
as shown in FIG.
2
. Once the assembly is arranged as illustrated in FIG.
2
and the anchoring means adjusted into the desired position, hardnenable material (typically concrete) is poured into the excavated trench to surround the form
28
. After the hardenable material has cured, the form
28
can be removed to reveal a completed trench having the contours of the lower surface
32
of the form
128
. To facilitate removal of the form
28
, however, the connecting rods
16
first must be removed from the rails
12
,
14
. In that the connecting rods
16
usually are welded to the rails, the rods typically must be cut from the rails with an electric grinder or saw.
Although adequately functional in design, there are several disadvantages associated with the prior art forming system set out in
FIGS. 1 and 2
. First, the upward buoyancy forces exerted on the form
28
often is sufficient to deepen the grooves
34
which receive the connecting rods
16
. As a result, the form
28
can be displaced upwardly, resulting in an uneven trench bottom surface. This result is particularly disadvantageous to the liquid displacing function of the trench in that it can create stagnant puddles of liquid therein. Furthermore, the connecting rods
16
can deform into an upwardly convex orientation, especially in wider form applications, due to the buoyancy forces imposed by the hardenable material. This deformation can cause misalignment or twisting of the frames, and can result in an uneven bottom trench surface, as described above.
Another disadvantage associated with the assembly illustrated in
FIGS. 1 and 2
, and other similar known systems, pertains to the attachment and removal of the connecting rods. Specifically, additional labor is required to weld each of the rods between the rails, which increases the cost and complexity of the assembly and makes it less economical to manufacture. In addition to the unnecessary labor associated with attachment of the connecting rods, additional labor is needed to remove them. Because the connecting rods normally must be cut away from the rails, the welded rod feature requires the presence of electrical power on a construction site or the use of gasoline powered tools. In the absence of such equipment, a hack saw must be used, making the removal of the form extremely labor intensive and quite expensive.
From the above, it can be appreciated that it would be advantageous to have a form assembly which is more resistant to the buoyancy forces imposed by the hardenable material, and which is less difficult to use.
SUMMARY OF THE INVENTION
Generally speaking, the present invention relates to an apparatus for forming a trench which is adapted to receive at least one grate that will cover the trench. The apparatus comprises first and second frame rails that are connected by at least one removable spacer. The spacer is sized and configured to maintain proper alignment and spacing between the first and second frame rails during the formation of the trench. The removable spacer is connected to the first and second frame rails with spacer securing means.
Once the first and second frame rails have been connected with the spacer securing means, the frame rails can be positioned within the excavated trench in a desired orientation. At this point, a hardenable material such as concrete can be poured into the excavated trench to surround the first and second frame rails. Once the hardenable material has cured to an adequate degree, the at least one removable spacer can be removed from the first and second frame rails and replaced with one or more grates. Typically these grates are fixedly secured to the first and second frame rails by using at least a portion of the securing means that was used to releasably secure the at least one spacer to the first and second frame rails. In that the securing means is used to secure both the at least one spacer and the one or more grates, the apparatus of the present invention can be more economically manufactured and more easily used.
The objects, features, and advantages of the present invention will become apparent upon reading of the following specification when taken in conjunction with the accompanying drawings.
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p
Lee Jong-Suk
Lillis Eileen D.
Thomas Kayden Horstemeyer & Risley LLP
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