Note: Descriptions are shown in the official language in which they were submitted.
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1177-5
IMPROVED SCREEDING APPARATUS AND COMPONENTS THEREFOR
The present invention relates to an improved screeding
apparatus and novel components particularly suited for use with
screeding apparatus.
BACKGROUND
Screeding machines known in the art are used to level
large areas of poured, uncured concrete, such as roads or large
floors found in warehouses or department stores. These screeding
machines are typically very large and heavy. Due to their weight,
they are typically restricted to use on the ground floor of most
buildings.
The weight of many screeding devices also affects their
design in tha some screeding machines are supported by wheels
which run adjacent to the area being screed:ed. With such designs,
screeding machines can generally work along a predetermined path
and are not particularly suited for screeding smaller areas off the
predetermined path. Other screeding machines have been designed to
be driven through poured concrete while supporting a screed behind
the wheels in order to displace excess concrete and to level the
concrete surface.
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Those skilled in the concrete a:rt will also appreciate
that poured concrete is quite often strengthened; for example, by
reinforcement bars, commonly known as rebar. The strength of the
rebar limits the weight of a screeding machine since the rebar
could be damaged by excessive weight.
Since, large multi-story buildings, such as department
stores and office buildings, commonly have concrete floors, it
would be very desirable to provide a screeding machine which is
relatively light and easily maneuverable.
It would also be desirable to provide a screeding
apparatus which can pass through poured, uncured concrete in order
to maximize the areas that can be screeded.
SUMMARY OF THE INVENT7CON
One aspect of the present invention comprises a novel
screeding apparatus which is designed to be driven through poured,
uncured concrete.
According to another aspect of the present invention, a
screeding apparatus is provided with novel wheels which can be
moved through concrete after screeding and without requiring the
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re-screeding of the areas through which the wheels have passed.
According to another aspect of the present invention, a
screeding apparatus is provided with at least one open frame wheel
and at least one vibrator for vibrating at least one wheel as the
wheel passes through uncured concrete. According to one preferred
embodiment of this invention, the vibrating mechanism is adjustable
in order to increase the force and/or frequency of the vibration
applied to the wheel. As used herein, the term "open frame" is
used to indicate that concrete can flow substantially freely around
or through the wheel. For example, according to some of the
illustrated wheel embodiments, uncured concrete can flow at least
partially in a direction perpendicular to tlZe path of travel of the
screeding machine.
These and other advantageous aspects of the present
invention will be apparent to those skilled in the art from the
following description and accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a screeding apparatus of
one embodiment of the present invention.
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FIG: 2 is a side view of an alternative embodiment of the
present invention.
FIG. 3 is a top view of the embodiment illustrated in
Figure 2.
FIGS. 4-13 illustrate rotatable supports for use with
various embodiments of the present invention.
DETAILED DESCRIPTION'
One preferred embodiment of the present invention
illustrated in Fig. 1 shows a screeding apparatus 10 comprising a
frame 20 which is movably supported by four wheel assemblies 50,
only two of which are clearly shown in Fig. 1. The illustrated
wheels are designed to pass directly through uncured concrete
either before or after that concrete sect_Lon has been screeded.
The illustrated wheel assemblies 50 are attached to the frame 20 by
a pivotal, four-bar linkage 60. Those skilled in the art will
appreciate that as screeding apparatus 10 is propelled through
uncured concrete, the wheels will ride up and down over various
objects, e.g., reinforcement bars, stones, etc. Therefore, it is
desirable to provide some degree of resilience between the wheel
assemblies 50 and the frame 20 with a four-bar linkage or some
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other controlled pivotal attachment.
The preferred illustrated wheel assemblies comprise wheel
segments 52 connected to wn axle 54 which is connected to a
hydraulic drive 56. Each wheel assembly is also advantageously
provided with a vibration assembly 58 which vibrates the wheel
segments 52 as they pass through the uncured concrete. The
vibration caused by vibration assembly 58 is preferably adjustable
with suitable controls (not shown). In this manner, the frequency,
force and amplitude of the vibration imparted to the wheel assembly
can be adjusted in order to provide sufficient vibration such that
wheel assemblies passing through screeded concrete will urge the
concrete to a sufficiently smooth finish so that further screeding
is unnecessary. It is also desirable to avoid too much vibration
in some situations. For example, those ski:Lled in the concrete art
will appreciate that concrete can be vibrated too much, the stones
will settle down to the bottom of the concrete and lose part of
their effectiveness.
According to this illustrated embodiment, the actual
screeding of the concrete surface is performed utilizing a laser
leveling system, such as that provided by Topcon Laser Systems,
Inc. 5758 W. Las PositaS Blvd., Pleasanton, California. Fig. 1
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illustrates a pair of detectors 80 for the laser leveling system.
The detectors are linked to a pneumatically operated vertical
control system comprising a hydraulic piston 90 and a linear
bearing assembly 110 which cooperate to provide vertical adjustment
to the screed 120 as the screeding apparatus 10 is propelled
through the uncured concrete. Linear bearing assembly 110
advantageously bears some of the load of the vertical support bar
115 while permitting the hydraulic piston 90 to provide the needed
vertical adjustments. In addition to vertical adjustment, the
angle of the screed 120 is also advantageously adjustable utilizing
hydraulic controls 130 which are pivotally connected to vertical
support bars 115.
Suitable controls are provided to operate and coordinate
each of the various operations of screeding apparatus 10. For
example, one or more potentiometers can be used to control the
speed and vibration of the screed as it passes through the uncured
concrete. As the particular types of controls can be selected by
one skilled in the art, these controls are mot explained in greater
detail herein.
An alternative embodiment of the present invention is
illustrated in Figures 2 and 3. In this embodiment, a screeding
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apparatus 200 is designed to be self-propelled through uncured
concrete in the direction indicated by arrow A. Located at the
forward end of screeding apparatus 200 is a plow blade 205 which is
height adjustable in order to remove large quantities of excess
concrete. Following adjustable plow blade 205 is a set of wheel
assemblies 220 which are vibrated by vibration mechanisms 225.
Additional concrete vibrators 230 are provided to impart desired
vibrations to the uncured concrete. Following the forward wheel
assemblies is a rotatable auger 240 which is preferable designed to
direct finer quantities of excess concrete either in a single
desired direction or out to both sides of the screeding apparatus
200. Following the rotatable auger is another set of wheel
assemblies, preferably having vibration mechanisms similar to the
forward wheel assemblies. Following the rear wheel assemblies is
a laser leveling apparatus, which can be of the type described in
reference to Figure 1. While a laser leveling system is
preferred, it is within the scope of the present invention to use
other leveling systems such as sonar" string line guide,
mathematical adjustment and manual adjustment.
Suitable controls are provided to operate and coordinate
each of the various operations of screeding apparatus 200
including, for example, the speed of rotation of the wheel
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assemblies, the direction of the wheel assemblies, the frequency
and force applied by the different vibrating mechanisms, the
heights and pitches of the plow augers and levelers. These
controls are most preferably remote controls.
Fig. 13 shows greater detail of a wheel assembly 50
wherein wheel segments 52 are connected to axle 54. In this
illustrated embodiment, the wheel assembly comprises four wheel
segments. Each wheel segment comprises a spoke portion 51 and a
support portion 53 comprising an arcuate surface. Each of the
illustrated support portions 53 of this illustrated embodiment
preferably pass through an angle of about 70 - 130° degrees. In
order to provide a relatively smooth ride, adjacent, spaced wheel
segments are positioned with circumferentially overlapping portions
in the same manner as wheel assemblies 220 illustrated in Fig. 2.
Other wheel designs may be utilized without departing
from the scope of the present invention. For example, wheels
similar to wheel assemblies 50 may be utilized using different
numbers of wheel segments which pass through greater or smaller
circumferential arcs.
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The present invention offers a number of different
designs for supporting a screeding apparatus. From the present
description, those skilled in the art will appreciate that a
particular support can be selected for a particular application.
Elevated decks and subgrades can include sand, gravel, metal
decks, wood decks, plastic barriers and different reinforcement
materials including rebar, wire mesh and/or fiber mesh. Therefore,
the particular support utilized will take the particular decking
and/or subgrade into account.
Figure 4 illustrates an alternative drive mechanism
wherein a plurality of radially-offset spherical supports 63 are
supported in space relation from a central hub by spoke portion
61. Each of the spoke portion 61 are connected to a cylindrical
axle 64. In order to facilitate repair and/or replacement of the
spherical support 63, in the event of damage or routine maintenance
and replacement, the axle 64 is also formed in a plurality of
segments which can easily be removed and replaced.
Figure 5 illustrates an alternative arrangement
comprising a plurality of radially-offset generally arcuate support
73 positioned at the ends of spoke portion 71 each of which are
connected to a axle segment 74.
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In an alternative embodiment illustrated in Fig. 6, a
plurality of closed loop supports 83 are connected via spoke
portions 81 to axle segments 84.
Figure 7 illustrates an alternative embodiment wherein
closed segments 93 are attached to axle segments. As with the
embodiment illustrated in Figs. 2 and 3, the generally arcuate,
closed supports 93 are preferably designed to overlap when viewed
along the longitudinal axis of axle portions 94. The support
sections 93 are most preferably formed with rounded outer faces in
order to provide a smooth motion for the screeding device through
uncured concrete. The supports 93 can either be solid or hollow.
Figures 8 and 9 illustrate further embodiments which
comprise disks 103 mounted on axles 104 and irregular disks 113
mounted on axle 114, respectively.
The embodiment of Fig. 10 comprises an open wire
structure 122 supported by rounded disks 123 and mounted on a
central axle 124. The spacing of the wire in this embodiment is
most preferably designed to permit the wire structure to be rotated
out of the uncured concrete while leaving the concrete sufficiently
smooth to avoid the need for additional sc:reeding.
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Figures 11 and 12 illustrate further embodiments of
supports of the present invention wherein a plurality of spaced
wheels are mounted on axles by spaced spokes or supports.
Another aspect of the present invention comprises method
of leveling uncured concrete comprising the steps of providing a
screeding apparatus comprising a plurality of supports which pass
through the uncured concrete and a leveling mechanism; passing said
screeding apparatus through said uncured concrete such that at
least one of said supports passes through a section of concrete
which has already been leveled by said leveling mechanism.
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