NZ601338B - Concrete mixer truck - Google Patents
Concrete mixer truck Download PDFInfo
- Publication number
- NZ601338B NZ601338B NZ601338A NZ60133812A NZ601338B NZ 601338 B NZ601338 B NZ 601338B NZ 601338 A NZ601338 A NZ 601338A NZ 60133812 A NZ60133812 A NZ 60133812A NZ 601338 B NZ601338 B NZ 601338B
- Authority
- NZ
- New Zealand
- Prior art keywords
- pressure
- mixer drum
- mixed concrete
- freshly mixed
- concrete
- Prior art date
Links
- 239000000463 material Substances 0.000 claims abstract description 40
- 239000012530 fluid Substances 0.000 claims abstract description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 24
- 238000005259 measurement Methods 0.000 description 7
- 230000000875 corresponding Effects 0.000 description 3
- 238000007689 inspection Methods 0.000 description 3
- 230000001629 suppression Effects 0.000 description 3
- 239000012615 aggregate Substances 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 210000003813 Thumb Anatomy 0.000 description 1
- 230000003213 activating Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000003247 decreasing Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006011 modification reaction Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001105 regulatory Effects 0.000 description 1
- 230000032258 transport Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
- B28C5/42—Apparatus specially adapted for being mounted on vehicles with provision for mixing during transport
- B28C5/4203—Details; Accessories
- B28C5/4206—Control apparatus; Drive systems, e.g. coupled to the vehicle drive-system
- B28C5/422—Controlling or measuring devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C7/00—Controlling the operation of apparatus for producing mixtures of clay or cement with other substances; Supplying or proportioning the ingredients for mixing clay or cement with other substances; Discharging the mixture
- B28C7/02—Controlling the operation of the mixing
- B28C7/022—Controlling the operation of the mixing by measuring the consistency or composition of the mixture, e.g. with supply of a missing component
- B28C7/026—Controlling the operation of the mixing by measuring the consistency or composition of the mixture, e.g. with supply of a missing component by measuring data of the driving system, e.g. rotational speed, torque, consumed power
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C7/00—Controlling the operation of apparatus for producing mixtures of clay or cement with other substances; Supplying or proportioning the ingredients for mixing clay or cement with other substances; Discharging the mixture
- B28C7/04—Supplying or proportioning the ingredients
- B28C7/12—Supplying or proportioning liquid ingredients
Abstract
Patent 601338 Disclosed is a concrete mixer truck having a mixer drum capable of carrying freshly mixed concrete. The mixer truck includes a driving device that is driven by rotation of an engine so as to drive the mixer drum to rotate using a fluid pressure of a working fluid. A pressure detector detects a pressure of the working fluid in the driving device and a controller has a material introduction determination unit that determines whether or not the freshly mixed concrete has been introduced into the mixer drum. A pressure determination unit determines whether or not the pressure of the working fluid detected by the pressure detector has fallen to a set pressure set in advance in accordance with a carrying amount and a fluidity of the freshly mixed concrete after the introduction of the materials for the freshly mixed concrete into the mixer drum. A notification device notifies an operator that the pressure of the working fluid in the driving device has fallen to the set pressure on the basis of the determination made by the pressure determination unit. ector detects a pressure of the working fluid in the driving device and a controller has a material introduction determination unit that determines whether or not the freshly mixed concrete has been introduced into the mixer drum. A pressure determination unit determines whether or not the pressure of the working fluid detected by the pressure detector has fallen to a set pressure set in advance in accordance with a carrying amount and a fluidity of the freshly mixed concrete after the introduction of the materials for the freshly mixed concrete into the mixer drum. A notification device notifies an operator that the pressure of the working fluid in the driving device has fallen to the set pressure on the basis of the determination made by the pressure determination unit.
Description
~ BIIIIIIII
*10060007903*
PATENTS FORM NO.5
601338
Fee No.4: $250.00
PATENTS ACT 1953
COMPLETE SPECIFICATION
"Concrete mixer truck"
I1WE Kayaba Industry Co., Ltd., a Japanese Company, of World Trade Center Bldg. 4-
1, Hamamatsu-cho 2-chome, Minato-ku, Tokyo 105-6111, Japan
hereby declare the invention, for which We pray that a patent may be granted to us, and the
method by which it is to be performed to be particularly described in and by the following
statement:
RECEIVED at IPONZ on 03 December 2012
CONCRETE MIXER TRUCK
FIELD OF THE INVENTION
This invention relates to a concrete mixer truck.
BACKGROUND OF THE INVENTION
A concrete mixer truck having a mixer drum capable of
carrying freshly mixed concrete is used conventionally. The freshly mixed
concrete is generated by introducing cement, aggregate, water, and so on
into the mixer drum of the concrete mixer truck and driving the mixer
drum to rotate so that the materials are mixed.
JP2005-022640A proposes a concrete mixer truck that
includes an inspection instrument for performing a quality inspection
when transported freshly mixed concrete is unloaded. In this concrete
mixer truck, a slump test for measuring a fluidity of the freshly mixed
concrete is performed on the freshly mixed concrete as the quality
inspection. In a slump test, a slump, which is a numerical value indicating
the fluidity of freshly mixed concrete, is measured. The fluidity of the
freshly mixed concrete increases as the measured slump increases.
SUMMARY OF THE INVENTION
In a conventional concrete mixer truck, however, the slump
of the freshly mixed concrete is adjusted by an operator using a rule of
thumb, and therefore variation occurs in the slump of the freshly mixed
concrete at the time of unloading, making it difficult to manage the
quality of the freshly mixed concrete.
The present invention seeks to provide a concrete mixer
RECEIVED at IPONZ on 03 December 2012
truck that can manage the quality of freshly mixed concrete.
To achieve the above aim, this invention provides a
concrete mixer truck having a mixer drum capable of carrying freshly
mixed concrete. The concrete mixer truck comprises a driving device that
is driven by rotation of an engine so as to drive the mixer drum to rotate
using a fluid pressure of a working fluid, a pressure detector that detects a
pressure of the working fluid in the driving device, a controller having a
material introduction determination unit that determines whether or not a
material for generating the freshly mixed concrete has been introduced
into the mixer drum, and a pressure determination unit that determines
whether or not the pressure of the working fluid detected by the pressure
detector has fallen to a set pressure set in advance in accordance with a
carrying amount and a fluidity of the freshly mixed concrete after the
introduction of the materials for the freshly mixed concrete into the mixer
drum, and a notification device that notifies an operator that the pressure
of the working fluid in the driving device has fallen to the set pressure on
the basis of the determination made by the pressure determination unit.
[0006A] According to one aspect the present invention provides a concrete
mixer truck having a mixer drum capable of carrying freshly mixed
concrete, including:
a driving device that is driven by rotation of an engine so as to drive
the mixer drum to rotate using a fluid pressure of a working fluid;
a pressure detector that detects a pressure of the working fluid in
the driving device;
a controller having a material introduction determination unit that
determines whether or not the freshly mixed concrete has been introduced
into the mixer drum, and a pressure determination unit that determines
whether or not the pressure of the working fluid detected by the pressure
detector has fallen to a set pressure set in advance in accordance with a
RECEIVED at IPONZ on 03 December 2012
- 2A-
carrying amount and a fluidity of the freshly mixed concrete after the
introduction of the materials for the freshly mixed concrete into the mixer
drum; and
a notification device that notifies an operator that the pressure of the
working fluid in the driving device has fallen to the set pressure on the
basis of the determination made by the pressure determination unit.
The details as well as other features and advantages of this
invention are set forth in the remainder of the specification and are
shown in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
is a plan view of a concrete mixer truck according to
an embodiment of this invention.
is a block diagram showing control of the
concrete mixer truck according to this embodiment of the invention.
is a flowchart showing a routine for adjusting a
slump
of freshly mixed concrete, which is performed in the concrete mixer truck
according to this embodiment of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A concrete mixer truck 100 according to an embodiment of
this invention will be described below with reference to the figures.
First, referring to FIGs. 1 and 2, the overall constitution of
the concrete mixer truck 100 will be described.
As shown in the concrete mixer truck 100 is a vehicle
including an operating cab 11 and a frame 1. The concrete mixer truck
100 includes a mixer drum 2 carried on the frame 1 to be capable of
carrying freshly mixed concrete, a driving device 4 that drives the mixer
drum 2 to rotate, and a controller 10 that controls rotation of the mixer
drum 2. The concrete mixer truck 100 transports freshly mixed concrete
carried in the mixer drum 2.
The freshly mixed concrete can be generated by introducing
materials such as cement, aggregate, and water into the mixer drum 2 of
the concrete mixer truck 100 and driving the mixer drum 2 to rotate so that
the materials are mixed.
The mixer drum 2 is a closed-end cylindrical container that is
carried rotatably on the frame 1. The mixer drum 2 is carried such that a
rotary axis thereof is oriented in a front-rear direction of the vehicle. The
mixer drum 2 is tilted in the front-rear direction when carried so as to
gradually increase in height toward a rear portion of the vehicle.
An opening portion is formed in a rear end of the mixer drum
2, and the freshly mixed concrete can be introduced and discharged
through the opening portion. The mixer drum 2 is driven to rotate using a
traveling engine 3 installed in the concrete mixer truck 100 as a power
source.
The driving device 4 is driven by rotation of the engine 3 so as
to drive the mixer drum 2 to rotate using a fluid pressure of a working fluid.
A rotary motion of a crankshaft in the engine 3 is transmitted to the driving
device 4 by a power take-off (PTO) mechanism 9 that continuously draws
power from the engine 3, and a drive shaft 8 (see that couples the
power take-off mechanism 9 to the driving device 4.
As shown in the power take-off mechanism 9 is
provided with a rotation sensor 9a that detects a rotation speed and
transmits a rotation speed signal corresponding to the detected rotation
speed to the controller 10. A rotation speed of the drive shaft 8 may also be
detected using the rotation sensor 9a.
In the driving device 4, working oil is used as the working
fluid. An incompressible fluid other than working oil may be used as the
working fluid. As shown in the driving device 4 includes a
hydraulic pump 5 that is driven by the engine 3 to serve as a fluid pressure
pump for discharging the operating fluid, and a hydraulic motor 6 that is
driven by the hydraulic pump 5 to serve as a fluid pressure motor for
driving the mixer drum 2 to rotate. The driving device 4 is capable of
rotating the mixer drum 2 forward and in reverse, and increasing and
decreasing a rotation speed of the mixer drum 2.
The hydraulic pump 5 is driven to rotate by power drawn
continuously from the engine 3 via the power take-off mechanism 9.
Accordingly, a rotation speed of the hydraulic pump 5 is greatly affected by
variation in the rotation speed of the engine 3 corresponding to a traveling
condition of the vehicle. Hence, in the concrete mixer truck 100,
operations of the hydraulic pump 5 and the hydraulic motor 6 are
controlled by the controller 10 so that the mixer drum 2 reaches target
rotation conditions in accordance with the rotation speed of the engine 3.
The hydraulic pump 5 is a swash plate type axial piston
pump having a variable capacity. Upon reception of a command signal
from the controller 10, the hydraulic pump 5 switches a tilt angle of the
pump to a positive rotation direction or a reverse rotation direction. The
hydraulic pump 5 includes a solenoid valve for adjusting the tilt angle. By
switching the solenoid valve, a discharge direction and a discharge capacity
of the hydraulic pump 5 are adjusted.
The working oil discharged from the hydraulic pump 5 is
supplied to the hydraulic motor 6, whereby the hydraulic motor 6 rotates.
The mixer drum 2 is coupled to the hydraulic motor 6 via a reduction gear 7.
The mixer drum 2 thus rotates in accordance with the rotation of the
hydraulic motor 6.
When the mixer drum 2 is operated to rotate forward by the
hydraulic pump 5, the freshly mixed concrete in the mixer drum 2 is
agitated. When the mixer drum 2 is operated to rotate in reverse by the
hydraulic pump 5, on the other hand, the freshly mixed concrete in the
mixer drum 2 is discharged to the outside through the opening portion in
the rear end.
An oil pressure of the working oil discharged from the
hydraulic pump 5 varies according to a carrying amount and a slump of
freshly mixed concrete carried in the mixer drum 2. The hydraulic pump 5
is provided with a pressure sensor 5a (see that serves as a pressure
detector for detecting the pressure of the discharged working oil.
The slump is a numerical value indicating a fluidity of the
freshly mixed concrete. The fluidity of the freshly mixed concrete increases
as the numerical value of the slump increases. In other words, as the
numerical value of the slump increases, the freshly mixed concrete becomes
softer, and as the numerical value of the slump decreases, the freshly mixed
concrete becomes harder. The freshly mixed concrete is mixed by driving
the mixer drum 2 to rotate, and as a result, the slump of the freshly mixed
concrete is adjusted so that an appropriate slump is realized at the time of
unloading.
As shown in the pressure sensor Sa transmits a load
pressure signal to the controller 10 in accordance with the detected
pressure of the working oil. The pressure sensor Sa may be provided in the
hydraulic motor 6 rather than the hydraulic pump 5 in order to detect the
pressure of the working oil in the hydraulic motor 6. In other words, the
pressure sensor Sa is used to detect the pressure of the working oil in the
driving device 4.
The hydraulic motor 6 is a swash plate type axial piston
motor having a variable capacity. The hydraulic motor 6 is driven to rotate
upon reception of a supply of the working oil discharged from the hydraulic
pump 5. The hydraulic motor 6 includes a solenoid valve that adjusts a tilt
angle of the motor upon reception of a command signal from the controller
. By switching the solenoid valve, the capacity of the hydraulic motor 6
is switched between two stages, namely a small capacity for high-speed
rotation and a large capacity for normal rotation.
The controller 10 controls the driving device 4. The
controller 10 is a microcomputer including a CPU (Central Processing Unit),
a ROM (Read-Only Memory), a RAM (Random Access Memory), and an I/O
interface (input/output interface). The RAM stores data used in
processing performed by the CPU. A control program of the CPU and so on
are stored in the ROM in advance. The I/O interface is used to input and
output information to and from a connected device. Control of the driving
device 4 is realized by operating the CPU, the RAM, and so on in accordance
with the program stored in the ROM.
As shown in when an operator starts the engine 3 by
operating an ignition switch in the operating cab 11, an ignition power
supply is input into the controller 10. As a result, a power supply relay 21
is switched such that a main power supply from a main battery 23 is
supplied to the controller 10, thereby activating the controller 10.
The concrete mixer truck 100 also includes a water tank 12
storing water, a water pressure pump 13 that aspirates and discharges the
water in the water tank 12, and an open/close valve 14 provided between
the water pressure pump 13 and the mixer drum 2.
The water pressure pump 13 and the open/ close valve 14 are
provided in a supply passage for supplying water into the mixer drum 2
from the water tank 12. The water pressure pump 13 is activated by an
activation signal from the controller 10. The open/close valve 14 is opened
and closed in accordance with an open/close signal from the controller 10.
The water in the water tank 12 is supplied into the mixer
drum 2 when the water pressure pump 13 is activated and the open/close
valve 14 is switched to an open state. The water in the water tank 12 can
be replenished from an external water line at a plant or the like.
Next, referring to control of the concrete mixer truck
100 will be described.
The controller 10 controls the operations of the hydraulic
pump 5 and the hydraulic motor 6 such that the rotation direction and
rotation speed of the mixer drum 2 reach target rotation conditions in
accordance with a calculated rotation speed of the engine 3. More
specifically, the controller 10 calculates a discharge direction and a
discharge capacity of the hydraulic pump 5 such that the rotation direction
and rotation speed of the mixer drum 2 reach the target rotation conditions.
Further, the controller 10 calculates the capacity of the hydraulic motor 6,
and outputs a control signal to the hydraulic pump 5 and a two-speed
switch signal to the hydraulic motor 6.
A load pressure signal is input into the controller 10 from the
hydraulic pump 5 via the pressure sensor 5a, and a rotation direction signal
and a rotation speed signal are input into the controller 10 from the
hydraulic motor 6 via sensors. The controller 10 controls the operations of
the hydraulic pump 5 and the hydraulic motor 6 on the basis of these input
signals.
The controller 10 includes a material introduction
determination unit 15 that determines whether or not the materials for
generating the freshly mixed concrete have been introduced into the mixer
drum 2, and a pressure determination unit 16 that determines whether or
not the working oil pressure detected by the pressure sensor 5a has fallen
to a preset set pressure.
The material introduction determination unit 15 determines
whether or not the materials for generating the freshly mixed concrete have
been introduced into the mixer drum 2 on the basis of the load pressure
signal from the pressure sensor 5a. When the materials are introduced
into the mixer drum 2, greater force is required to rotate the mixer drum 2
than before the materials are introduced. Therefore, the discharge
pressure of the hydraulic pump 5 increases.
The material introduction determination unit 15 determines
that the materials have been introduced by detecting an increase in the
discharge pressure. More specifically, the material introduction
determination unit 15 determines that the materials have been introduced
when an increase width of the discharge pressure of the hydraulic pump 5
exceeds a preset predetermined increase width.
In a steady state, the mixer drum 2 is driven by the driving
device 4 to perform agitation rotation, which is rotation at a rotation speed
at which a quality of the freshly mixed concrete in the mixer drum 2 can be
maintained. When the material introduction determination unit 15
determines that the materials have been introduced into the mixer drum 2,
the mixer drum 2 switches to mixing rotation, which is rotation at a higher
speed than the agitation rotation. Thus, the materials in the mixer drum 2
can be mixed to generate the freshly mixed concrete.
The pressure determination unit 16 determines whether or
not the freshly mixed concrete in the mixer drum 2 has reached an
appropriate slump on the basis of the load pressure signal from the
pressure sensor 5a. After a set time has elapsed following introduction of
the materials for the freshly mixed concrete into the mixer drum 2, the
pressure determination unit 16 determines on the basis of the signal from
the pressure sensor 5a whether or not the discharge pressure of the
hydraulic pump 5 has fallen to the set pressure.
When the freshly mixed concrete in the mixer drum 2 is
mixed, the freshly mixed concrete gradually becomes softer, and therefore
the force required to rotate the mixer drum 2 gradually decreases.
Accordingly, the discharge pressure of the hydraulic pump 5 gradually falls.
When the discharge pressure of the hydraulic pump 5 falls below the preset
set pressure, the pressure determination unit 16 determines that the
freshly mixed concrete has reached the appropriate slump.
The set pressure is set in advance in accordance with the
amount of freshly mixed concrete carried in the mixer drum 2 as a working
oil pressure at which the freshly mixed concrete in the mixer drum 2
reaches the appropriate slump.
To set the set pressure, first, an overall weight of the mixer
drum 2, including the freshly mixed concrete carried therein, is measured
using a weight sensor. The amount of carried freshly mixed concrete is
then calculated by subtracting the weight of the mixer drum 2 from the
measured weight.
Next, the mixer drum 2 is caused to perform the high-speed
mixing rotation so that the freshly mixed concrete is mixed, whereupon the
mixer drum 2 is switched to low-speed measurement rotation. The
measurement rotation is rotation at a rotation speed for suppressing
variation in the working oil pressure accompanying rotation of the mixer
drum 2.
Next, a part of the freshly mixed concrete is removed from the
mixer drum 2 and subjected to a slump test to measure the slump of the
freshly mixed concrete. When the measured slump takes an appropriate
numerical value, the discharge pressure of the hydraulic pump 5 is
measured while the mixer drum 2 rotates in accordance with the
measurement rotation. The discharge pressure of the hydraulic pump 5 at
this time serves as the set pressure corresponding to the amount of freshly
mixed concrete carried in the mixer drum 2.
It should be noted that the set pressure may be calculated in
advance by the operator on the basis of the carrying amount and the slump
of the freshly mixed concrete and input through an input unit provided on
an operating device 32.
A parking brake 31, the operating device 32 for operating the
mixer drum 2, and a notification device 35 for issuing notifications to the
operator are disposed in the operating cab 11.
A detector that detects a lever position of the parking brake
31 is provided on the parking brake 31. When the parking brake 31 is
applied, a stop signal is output to the controller 10 from a detector.
A knob type operating switch 32a for switching the rotation
direction and rotation speed of the mixer drum 2, a stop switch 32b for
halting rotation of the mixer drum 2 in an emergency, and an automatic
agitation switch 32c for causing the mixer drum 2 to perform the agitation
rotation automatically are provided on the operating device 32. Further,
an introduction mode switch 32d for switching an introduction mode in
which the materials of the freshly mixed concrete can be introduced into the
mixer drum 2, a slump readjustment switch 32e for readjusting the slump
of the freshly mixed concrete in the mixer drum 2, and a mixing switch 32f
for mixing the freshly mixed concrete in the mixer drum 2 for a
predetermined time are provided on the operating device 32.
When the operator operates the respective switches 32a to
32f, command signals are output to the controller 10 from the operating
device 32. On the basis of the command signals, the controller 10
determines the target rotation conditions of the mixer drum 2, or more
specifically the rotation direction and rotation speed.
A rotation operation of the mixer drum 2 will now be
described. When the automatic agitation switch 32c is ON, the stop signal
is not output from the parking brake 31, and when a vehicle speed is equal
to or higher than a predetermined speed, the controller 10 determines that
the vehicle is traveling. Accordingly, the controller 10 causes the mixer
drum 2 to perform the agitation rotation automatically, thereby preventing
discharge of the freshly mixed concrete and maintaining the quality of the
freshly mixed concrete.
When the automatic agitation switch 32c is OFF, on the other
hand, the controller 10 may operate the operating device 32 to rotate the
mixer drum 2 in reverse so that the freshly mixed concrete in the mixer
drum 2 can be discharged to the outside even though the vehicle is traveling.
The controller 10 may likewise operate the operating device 32 to rotate the
mixer drum 2 in reverse so that the freshly mixed concrete in the mixer
drum 2 can be discharged to the outside when the stop signal is output
from the parking brake 31.
On the basis of the determination made by the pressure
determination unit 16, the notification device 35 notifies the operator that
the working oil pressure has fallen to the set pressure. The notification
device 35 is a buzzer that notifies the operator by sound, a lamp that
provides the operator with visible notification, or similar.
A rear portion operating device 38 with which the mixer drum
2 can be operated from the exterior of the concrete mixer truck 100 is
disposed on a rear portion of the concrete mixer truck 100. Similarly to the
operating device 32, the rear portion operating device 38 is provided with a
knob type operating switch 38a for switching the rotation direction and
rotation speed of the mixer drum 2, and a stop switch 38b for halting
rotation of the mixer drum 2 in an emergency. When the operator operates
the rear portion operating device 38, command signals are output to the
controller 10 from the rear portion operating device 38.
Further, an automatic washing/mixing operating device 39
that enables automatic washing of the interior of the mixer drum 2 and
mixing of the freshly mixed concrete from the exterior of the concrete mixer
truck 100 is disposed on the concrete mixer truck 100.
Next, referring to a routine for adjusting the slump of
the freshly mixed concrete, which is executed on the concrete mixer truck
100 by the controller 10, will be described. The controller 10 executes this
routine repeatedly at flxed time intervals of 10 milliseconds, for example,
while the engine 3 is operative.
The operator drives the concrete mixer truck 100 in advance
to a material introduction position on a plant, and then stops the vehicle.
When the concrete mixer truck 100 is stationary in the material
introduction position and preparation for material introduction is complete,
the operator operates the introduction mode switch 32d.
In a step 1, the introduction mode switch 32d is operated by
the operator. When the introduction mode switch 32d is operated, the
controller 10 switches to a material introduction mode and then advances
to a step 2.
In the step 2, agitation rotation is begun in the mixer drum 2.
In a step 3, a determination is made as to whether or not the
materials for the freshly mixed concrete have been introduced into the
mixer drum 2. When it is determined in the step 3 that the materials for
the freshly mixed concrete have been introduced, the routine advances to a
step 4. When it is determined in the step 3 that the materials for the
freshly mixed concrete have not been introduced, on the other hand, the
routine returns.
In the step 4, the mixer drum 2 is switched to the high-speed
mixing operation. As a result, the materials of the freshly mixed concrete
introduced into the mixer drum 2 are mixed.
[0062) In a step 5, a determination is made as to whether or not a
predetermined time has elapsed following the start of the mixing operation
in the mixer drum 2. When it is determined in the step 5 that the
predetermined time has elapsed, the routine advances to a step 6. The
predetermined time is set at a time required to generate the freshly mixed
concrete through the mixing operation in the mixer drum 2 following
introduction of the materials into the mixer drum 2.
[0063) In the step 6, the mixer drum 2 is switched to the low-speed
measurement rotation. The rotation speed of the mixer drum 2 during the
measurement rotation may be identical to the rotation speed during the
agitation rotation.
[0064) In a step 7, a determination is made as to whether or not the
discharge pressure of the hydraulic pump 5 has fallen to the set pressure.
When it is determined in the step 7 that the discharge pressure of the
hydraulic pump 5 has not fallen to the set pressure, the routine advances to
a step 10.
[0065) In the step 10, the water pressure pump 13 is activated and
the open/close valve 14 is switched to the open state for a set time. As a
result, a predetermined amount of the water stored in the water tank 12 is
supplied to the mixer drum 2. At this time, the freshly mixed concrete in
the mixer drum 2 has not yet been mixed to the appropriate slump, and
therefore, by supplying the predetermined amount of water to the mixer
drum 2, the freshly mixed concrete in the mixer drum 2 is brought closer to
the appropriate slump.
[0066) After the predetermined amount of water has been supplied
to the mixer drum 2 in the step 10, the routine advances to the step 4.
Accordingly, the freshly mixed concrete in the mixer drum 2 is mixed
further such that the slump of the freshly mixed concrete is adjusted.
When it is determined in the step 7 that the discharge
pressure of the hydraulic pump 5 has fallen to the set pressure, on the
other hand, this means that the freshly mixed concrete in the mixer drum 2
is at the appropriate slump, and therefore the routine advances to a step 8.
In the step 8, the notification device 35 is switched ON. By
notifying the operator that the pressure of the working in the driving device
4 has fallen to or below the set pressure, the operator can be informed that
the freshly mixed concrete in the mixer drum 2 has been adjusted to a
predetermined slump.
Hence, in contrast to a conventional concrete mixer truck, in
which the slump of the freshly mixed concrete is adjusted by the operator
using a rule of thumb, the freshly mixed concrete carried on the concrete
mixer truck 100 can be regulated to an appropriate slump automatically.
As a result, variation in the slump of the freshly mixed concrete at the time
of unloading can be suppressed, and the quality of the freshly mixed
concrete can be managed.
In a step 9, the mixer drum 2 is switched to the agitation
rotation. When the mixer drum 2 is switched to the agitation rotation in
the step 9, slump adjustment of the freshly mixed concrete is complete, and
therefore the routine advances to a step 11.
In the step 11, a determination is made as to whether or not
the slump readjustment switch 32e has been operated. For example, the
operator may readjust the slump of the freshly mixed concrete by operating
the slump readjustment switch 32e before the freshly mixed concrete is
discharged or the like. In so doing, the quality of the freshly mixed
concrete can be checked immediately prior to unloading.
When it is determined in the step 11 that the slump
readjustment switch 32e has been operated, the routine advances to the
step 6, where the mixer drum 2 is switched to the measurement rotation,
and then to the step 7, where the determination as to whether or not the
discharge pressure of the hydraulic pump 5 has fallen to the set pressure is
made again. When it is determined in the step 11 that the slump
readjustment switch 32e has not been operated, on the other hand, the
routine returns.
It should be noted that the operator may switch the mixer
drum 2 to the high-speed mixing rotation for a predetermined time to remix
the freshly mixed concrete by operating the mixing switch 32f before the
freshly mixed concrete is discharged.
With the embodiment described above, the following effects
are obtained.
The discharge pressure of the hydraulic pump 5 for driving
the mixer drum 2 to rotate is detected by the pressure sensor Sa, and when
the detected pressure falls to the set pressure, the operator is notified
thereof by the notification device 35. The discharge pressure of the
hydraulic pump 5 varies according to the carrying amount and the slump of
the freshly mixed concrete in the mixer drum 2. The set pressure is set in
advance in accordance with the carrying amount and the slump of the
freshly mixed concrete.
By notifying the operator that the discharge pressure of the
hydraulic pump 5 has fallen to the set pressure, the operator can be
informed that the freshly mixed concrete in the mixer drum has been
adjusted to a predetermined slump. As a result, variation in the slump of
the freshly mixed concrete at the time of unloading can be suppressed, and
the quality of the freshly mixed concrete can be managed.
[0077) Although the invention has been described above with
reference to certain embodiments, the invention is not limited to the
embodiments described above. Modifications and variations of the
embodiments described above will occur to those skilled in the art, within
the scope of the claims.
For example, in the above embodiment, the mixer drum 2 is
switched to the mixing rotation after the materials are introduced into the
mixer drum 2 and then switched to the measurement rotation after the
predetermined time has elapsed following the switch to the mixing rotation.
Further, the pressure determination unit 16 determines whether or not the
discharge pressure of the hydraulic pump 5 has fallen to the set pressure.
However, this invention is not limited thereto, and instead,
after the materials have been introduced into the mixer drum 2 and the
mixer drum 2 has been switched to the mixing rotation, the pressure
determination unit 16 may determine whether or not the discharge
pressure of the hydraulic pump 5 has fallen to the set pressure
continuously while the mixer drum 2 continues to perform the mixing
rotation.
In this constitution, the mixer drum 2 is switched from the
mixing rotation to the agitation rotation after the pressure determination
unit 16 determines that the discharge pressure of the hydraulic pump 5 has
fallen to the set pressure. Further, in this constitution, the predetermined
amount of water is supplied to the mixer drum 2 in the step 10 when the
pressure determination unit 16 determines that the discharge pressure of
RECEIVED at IPONZ on 03 December 2012
the hydraulic pump 5 has not fallen to the set pressure following the
elapse of a predetermined time after the mixer drum 2 is switched to the
mixing rotation.
The embodiments of this invention in which an exclusive
property or privilege is claimed are defined as follows:
Throughout this specification and the claims which follow,
unless the context requires otherwise, the word "comprise", and variations
such as "comprises" or "comprising", will be understood to imply the
inclusion of a stated integer or step or group of integers or steps but not
the exclusion of any other integer or step or group of integers or steps.
The reference in this specification to any prior publication
(or information derived from it), or to any matter which is known, is not,
and should not be taken as, an acknowledgement or admission or any
form of suggestion that that prior publication (or information derived from
it) or known matter forms part of the common general knowledge in the
field of endeavour to which this specification relates.
RECEIVED at IPONZ on 03 December 2012
C.lNRPonbl\DCCILGLI4771 1 26JDOC-1 112912012
Claims (3)
- CLAIMS 5 1. A concrete mixer truck having a mixer drum capable of carrying freshly mixed concrete, including: a driving device that is driven by rotation of an engine so as to drive the mixer drum to rotate using a fluid pressure of a working fluid; a pressure detector that detects a pressure of the working fluid in 10 the driving device; a controller having a material introduction determination unit that determines whether or not the freshly mixed concrete has been introduced into the mixer drum, and a pressure determination unit that determines whether or not the pressure of the working fluid detected by the pressure 15 detector has fallen to a set pressure set in advance in accordance with a carrying amount and a fluidity of the freshly mixed concrete after the introduction of the materials for the freshly mixed concrete into the mixer drum; and a notification device that notifies an operator that the pressure of 20 the working fluid in the driving device has fallen to the set pressure on the basis of the determination made by the pressure determination unit.
- 2. The concrete mixer truck as defined in Claim 1, wherein the set pressure is set in advance in accordance with the carrying amount of the 25 freshly mixed concrete in the mixer drum as a working fluid pressure at which a slump, which is a numerical value indicating the fluidity of the freshly mixed concrete in the mixer drum, reaches an appropriate numerical value that the fluidity of the freshly mixed concrete is appropriate at the time of unloading.
- 3. The concrete mixer truck as defined in Claim 1 or 2, wherein, in a
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2011204860 | 2011-07-19 | ||
AU2011204860A AU2011204860B2 (en) | 2011-07-19 | 2011-07-19 | Concrete mixer truck |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ601338A NZ601338A (en) | 2012-12-21 |
NZ601338B true NZ601338B (en) | 2013-03-22 |
Family
ID=
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