Note: Descriptions are shown in the official language in which they were submitted.
WO 95/27602
PCT/US95/00084
A CONCRETE MIXER WITH RECIPROCATING DISCHARGE CHUTE
Background of the Invention
1. Field of the Invention
This invention relates to a concrete mixer and more
particularly to a horizontal drum concrete batch mixer.
2. Description of Related Art
Historically, concrete has been mixed in many types of
revolving drum mixers. Such mixers are powered either with
gasoline engines or electrical motors. The drums normally
are rotated in a single direction at a constant speed.
Discharge from the mixer is sometimes accomplished by
tilting a chute into the drum's interior. Such concrete
mixers usually utilize a horizontally disposed and
rotatably mounted mixing drum. Such horizontal drum mixers
are limited in production capacity due to the excessive
time required for the discharge of the mixed concrete
therefrom.
As mixer and production capacity requirements have
steadily increased, the trend in the industry has been to
resort to a tilting type mixer configuration. High
capacity tilting mixers have been the accepted design in
the concrete industry for many years with the chief
advantage being high production capacity due to the fast
discharge rate as the mixer body is tilted toward its cone-
shaped discharge end. Such tilting mixers, however, are
less portable and require substantial foundations to
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prevent overturning of the mixer as the mixer tilts
beyond the supporting framework during discharge.
In portable applications, tilting mixers are at a
further disadvantage due to their physical size. For
example, in some tilting mixers, the discharge cone must
be removed for transport to come within highway width
limits. Further, the weight, power requirements, and
cost of tilting mixers is greatly increased by the
necessary addition of the powered tilting mechanism.
Summary of the Invention
The invention in one broad aspect provides a
concrete batch mixer comprising a horizontally disposed,
hollow, cylindrical mixer drum having first and second
end walls at the opposite ends thereof, the first end
wall having an inlet opening formed therein for
introducing concrete materials into the mixer drum, and
the second end wall having a discharge opening formed
therein for discharging the mixed concrete from the mixer
drum. Means is provided for rotating the mixer drum to
mix the concrete materials therein and to discharge the
concrete materials therefrom, the mixer drum having
mixing blades provided in the interior thereof for mixing
the concrete materials, and the mixer drum includes means
in the interior thereof for transferring the mixed
concrete materials towards the second end wall. A
discharge chute is selectively movably positioned in the
discharge opening and includes inner and outer ends, the
discharge chute being selectively movable from a first
non-discharge position to a second discharge position.
The discharge chute includes a vertically disposed inner
end plate a chute member extending outwardly from the
inner end plate, and a vertically disposed outer end
plate. The chute member extending outwardly through the
outer end plate, and the chute member has an open upper
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end between the inner and outer end plates for
receiving mixed concrete materials therein when the
discharge chute is in its discharge position. The
inner end plate closing the discharge opening when
the discharge chute is in its said non-discharge
position. The outer end plate is positioned
adjacent the discharge opening when the discharge
chute is in its discharge position, and the open
upper end of the chute member is positioned inwardly
of the discharge opening when the discharge chute is
positioned in its discharge position. Means is
provided in the interior of the mixer drum adjacent
the second end wall for delivering the mixed
concrete into the open upper end of the chute member
so that the mixed concrete is discharged from the
mixer drum outwardly through the discharge chute.
In another aspect, the concrete batch mixer
above includes means for rotating the mixer drum in
a first mixing direction and to rotate the mixer
drum in a second discharge direction. The mixing
blades provided in the interior of the drum are
configured to mix concrete materials therein when
the mixer drum is rotated in the first mixing
direction and the means provided in the interior of
the mixer drum for delivering the mixed concrete
into the open upper end of the chute member are
configured to deliver the mixed concrete into the
open upper end of the chute member when the mixer
drum is rotated in the second discharge direction.
The new drum may be mounted on a trailer for
transport to a job site.
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The mixer drum may be mounted on a trailer for transport
to the job site.
Accordingly, the invention seeks to provide a
horizontal drum concrete batch mixer including a
discharge chute which is movable with respect to the
discharge opening of the drum.
Further, the invention seeks to provide a horizontal
drum concrete batch mixer which includes a novel means
for delivering the mixed concrete into a movable chute
member which may be moved between discharge and non-
discharge positions.
Still further, the invention seeks to provide a
horizontal drum concrete batch mixer which has high
discharge capabilities.
Still further, the invention seeks to provide a
horizontal drum concrete batch mixer having high mixing
capability and high discharge capability thereby avoiding
the necessity of tilting the drum for discharge.
Further still, the invention seeks to provide a more
economical and mechanically simple concrete mixer which
is more easily transported and which requires less in the
way of installation and foundation support at the job
site.
Yet further, the invention seeks to provide a system
that is more simple to manufacture and assemble due to
its cylindrical shape with flat end plates as compared to
tilting mixers which require cone ends and the necessary
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additional supporting framework to permit
tilting to discharge.
Moreover, the invention seeks to provide a
system which more efficiently contains and
exhausts dust particles by end seals which
remain engaged while those in tilting mixers
must break away during discharge exposing the
interior to atmosphere.
These and other aspects will be apparent
to those skilled in the art.
Brief Description of the Drawings
Figure 1 is a perspective view of the
horizontal drum concrete batch mixer of this
invention;
Figure 2 is an end elevational view of the
mixer;
Figure 3 is a side elevational view of the
mixer;
Figure 4 is a view similar to Figure 3
except that portions have been cut away to more
fully illustrate the invention;
Figure 5 is a partial perspective view
illustrating the internal transfer blades,
mixing blades and discharge buckets; and
Figure 6 is a side view illustrating the
mixer mounted on a mobile chassis.
Description of the Preferred Embodiment
The horizontal drum concrete batch
mixer of this invention is referred to
generally by the reference numeral
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WO 95/27602 PC"T/IJS95/00084
and includes a horizontally disposed drum 12 rotatably
mounted on a frame means 14. For purposes of description,
drum 12 will be described as including a cylindrical
portion 16 having an inlet end wall 18 and a discharge end
wall 20.
A plurality of horizontally disposed drive rollers 22
support the drum 12 and are operatively connected to a
suitable power source for rotating the drum in a first
mixing direction and an opposite discharge direction as
will be described in more detail hereinafter.
Inlet end wall 18 is provided with an inlet chute 24
which communicates with the interior of the drum 12 to
enable the concrete materials to be delivered to the
interior of the drum. An elongated flexible exhaust tube
26 is in operative communication with the inlet chute 24
for exhausting dust therefrom to prevent the escape of the
same to the atmosphere.
Discharge end wall 20 is provided with a centrally
disposed circular opening 28 formed therein in which is
movably mounted a discharge chute 30. As seen in Figure 1,
discharge chute 30 is movably mounted on a supporting frame
32 which extends upwardly from the frame means 14.
Discharge chute 30 includes an inner end plate 34 which is
disc-shaped and which has a diameter greater than the '
diameter of the opening 28. Inner end plate 34 is provided
with a peripheral seal 36 extending around its outer
surface which is adapted to sealably engage the inner
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surface of discharge end wall 20 when the discharge chute
30 is in the mixing position illustrated by solid lines in
Figure 4.
A substantially U-shaped chute member 38 extends
outwardly from inner end plate 34 and includes a bottom
wall 40 and opposite side walls 42 and 43. Chute member 38
extends downwardly and outwardly from the inner end plate
34 as illustrated in Figure 4. The numeral 44 refers to an
outer end plate of the discharge chute which is secured to
the chute member 38 as illustrated in Figures 1 and 4.
Chute member 38 is open at its upper end between inner end
plate 34 and outer end plate 44. As seen in Figure 1,
chute member 34 is enclosed by a top portion 46 outwardly
of outer end plate 44. Outer end plate 44 is adapted to
sealably engage the outer surface of end wall 20 of drum 12
when the discharge chute 30 has been moved inwardly into
the drum for discharge purposes as will be described in
more detail hereinafter.
Discharge chute 30 includes a pair of slide members 48
and 50 which roll upon the upper surfaces of the frame
members 52 and 54 of frame 32 as illustrated in Figure 1.
A pair of hydraulic cylinders or the like are operatively
connected to the slide members 48 and 50 respectively as
illustrated in Figure 1 and are referred to generally by
the reference numerals 56 and 58. The hydraulic cylinders
56 and 58 are adapted to move the discharge chute 30 from
the mixing position illustrated by solid lines in Figure 4
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to the discharge position illustrated by broken lines in
Figure 4.
The interior of drum 12 is provided with a plurality
of spaced-apart transfer blades 60 which extend around the
interior of the cylindrical portion 16 as illustrated in
the drawings. As seen in the drawings, the transfer blades
60 are disposed at an angle with respect to the
longitudinal axis of the drum 12 so that the blades will
tend to maintain the contents in the drum towards the inlet
end of the drum during the mixing operation but which are
designed to transfer the mixed concrete towards the
discharge end of the drum when the drum is rotated in its
discharge direction. A plurality of spaced-apart mixing
blades 62 are secured to the transfer blade 60 as
illustrated in the drawings and are designed to mix the
concrete in the drum as the drum is rotated in its mixing
direction.
A plurality of spaced-apart discharge blades or
buckets 64 are secured to the interior surface of drum 12
adjacent discharge end wall 20 as best illustrated in
Figures 4 and 5. The discharge blades or buckets 64 extend
around the discharge opening 28 and are designed to dump or
drop the mixed concrete into the open upper end of the
chute member 38 when the discharge chute 30 is in its
discharge position and the drum 12 is rotated in its
discharge direction.
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. Figure 6 illustrates the horizontal drum concrete
batch mixer 10 of this invention mounted on a mobile
chassis for transportation purposes to the job site. As
seen in Figure 6, mixer 10 is mounted on a bed 66 of a
mobile chassis 68 which is in the form of a trailer.
Chassis 68 includes a hitch means 70 at its forward end
which is bolted to the bed 68 and which includes a king pin
72 provided thereon for connection to the fifth wheel of a
truck or the like. The numeral 74 refers to a running gear
assembly which is bolted to the rear of the bed 66 as
illustrated in Figure 6. Thus, the mixer 10 may be mounted
on the mobile chassis or trailer 68 and transported to the
desired job site. When the mixer 10 has been transported
to the job site, the hitch means 60 and running gear
assembly 74 may be removed from the bed 66 with the bed 66
being placed on a suitable supporting surface.
In operation, the discharge chute 30 is normally in
the position illustrated by solid lines in Figure 4. The
power means for the mixer will normally be activated to
rotate the drum 12 in its mixing direction. The materials
for the concrete are then delivered to the interior of the
drum 02 through the inlet chute 24. The rotation of the
drum 12 by the power means causes the components of the
concrete to be mixed through the action of the mixing
blades 62. During the mixing operation, the transfer
blades 60 tend to maintain the concrete in the drum towards
the inlet end of the mixer drum. During the mixing
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operation, the inner end plate 34 of discharge chute 30
sealably engages the interior surface of the discharge end
wall 20 around discharge opening 28 to prevent the escape
of materials therethrough. The exhaust tube 26 also
prevents the escape of dust to the atmosphere.
When the concrete has been mixed and it is desired to
discharge the concrete from the drum 12, the rotation of
the drum is reversed from its mixing direction to its
discharge direction. The hydraulic cylinders 56 and 58 are
then actuated to cause the discharge chute 30 to be moved
inwardly with respect to the drum 12 from the position
illustrated by solid lines in Figure 4 to the position
illustrated by broken lines in Figure 4. The discharge
position of the discharge chute 30 is also illustrated in
Figure 1. As the drum 12 is rotated in its discharge
direction, the transfer blades 60 transfer the concrete in
the drum towards the discharge end thereof. The discharge
blades or buckets 64 pick up the concrete in the drum and
move the same upwardly as the drum is rotated. As each
discharge blade or bucket 64 moves towards its vertically
disposed position above the open upper end of the chute
member 38, the concrete thereon falls downwardly therefrom
into the open upper end of the chute member 38. The mixed
concrete which falls into the chute member 38 then passes
outwardly through the chute member 38. During the
discharge operation, the outer end plate 44 sealably
engages the outer surface of the discharge end'wall 20 of
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drum 12 to prevent the escape of materials from the drum
other than through the discharge chute 30.
Thus it can be seen that a novel horizontal drum
concrete batch mixer has been provided which has a large
capacity and which does not require the tilting of the drum
during discharge. The mixer of this invention not only has
high mixing capability but also has high discharge
capability. Thus it can be seen that the invention
accomplishes at least all of its stated objectives.
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