FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. CONTROLLER, BOOM DEVICE, AND CRANE VEHICLE
2.
1. (A) TADANO LTD.
(B) Japan
(C) Ko-34, Shinden-cho, Takamatsu-shi, Kagawa 7610185 JAPAN
The following specification particularly describes the invention and the manner in which it is to be
performed.

2
Technical Field
[0001]
The present invention relates to a controller that controls
a boom device including a boom and a winch, a boom device, and
a crane vehicle mounted with the boom device.
Background Art
[0002]
A crane vehicle is generally mounted with a boom device (see
Patent Literature 1). The boom device disclosed in Patent
Literature 1 includes a telescopic boom, a boom drive unit, a
winch having a wire drum around which a wire is wound, a winch
drive unit, a load hook provided at a tip of the wire, and a
hook fixing ring. The boom is supported by a swivel base such
that the boom can be raised and lowered. The boom drive unit
extends and retracts and raises and lowers the boom. The wire
is pulled out from the wire drum and wound around a distal end
of the boom, and the load hook is provided at an end of the wire.
The winch drive unit drives the winch to wind the wire around
the wire drum or to unwind the wire from the wire drum. The
hook fixing ring is provided on the swivel base, and the load
hook is hung on and fixed to the hook fixing ring during crane
travelling (non-working time).
[0003]
The boom device disclosed in Patent Literature 1 includes
3
a control device that controls the boom drive unit and the winch
drive unit in order to perform a safe boom storage operation
at the end of work and a safe boom unfolding operation at the
start of work. The control device controls the drive of the
winch drive unit in the boom storage operation. Specifically,
in the storage operation, an operator first retracts and raises
the boom, and hangs the load hook on the hook fixing ring. Next,
the operator operates a boom drive device to lower the boom.
The control device winds up the wire while automatically
controlling the winch drive unit according to the lowering of
the boom so that the wire does not loosen.
[0004]
The control device controls the drive of the winch based on
a wire length S detected by a sensor for detecting a length of
the wire and a derrick angle θ of the boom detected by a derrick
angle sensor such that the wire length S and the derrick angle
θ have an ideal correspondence D (the wire is not excessively
loosened or stretched). The ideal correspondence D is
obtained by experiments or simulation using an actual machine,
and is stored in a storage unit in advance.
Citation List
Patent Literature
[0005]
Patent Literature 1: Japanese Patent Laid-Open No. 7-172775
4
Summary of Invention
Technical Problem
[0006]
The ideal correspondence D varies depending on geometry
constituted by a length of the boom in a retracted state, a
position of the distal end around which the wire is wound, a
derrick fulcrum position, a position of the hook fixing ring,
and the like. In this case, the ideal correspondence D, which
is unique to each type of boom devices, needs to be determined,
and the control device needs to be designed for various boom
devices.
[0007]
Therefore, an object of the present invention is to provide
a controller that can automatically store or raise a boom and
can be commonly used for various boom devices.
Solution to Problem
[0008]
(1) A controller according to the present invention is used
for a boom device including a base, a boom supported by the base
and capable of being raised and lowered between a lowered
position and a raised position, a winch having a wire wound
around a wire drum and wound around a distal end of the boom,
a load hook provided at a tip of the wire, a first drive source
configured to raise and lower the boom, a second drive source
configured to drive the winch and to unwind the wire from the
5
wire drum or wind the wire around the wire drum, an engaging
member provided on the base and to which the load hook suspended
from the distal end of the boom at the raised position is engaged
in a detachable manner, a derrick angle sensor configured to
detect a derrick angle of the boom, and a length sensor
configured to detect an unwinding length of the wire from the
distal end of the boom. The controller according to the
present invention includes a memory configured to store
specified values corresponding to a length of the boom and a
position of the engaging member with respect to a derrick
fulcrum of the boom. The controller according to the present
invention calculates a displacement distance from the distal
end of the boom to the engaging member based on the derrick angle
of the boom detected by the derrick angle sensor and the
specified values read out from the memory, and executes an
automatic boom drive process of driving the winch while raising
or lowering the boom between the lowered position and the raised
position in a state where the load hook is engaged with the
engaging member such that the displacement distance is a
distance corresponding to the length detected by the length
sensor, or a wire speed which is an unwinding speed or a winding
speed of the wire is calculated based on the calculated
displacement distance, and the calculated wire seed is a speed
corresponding to a detected wire speed calculated based on a
detected value of the length sensor.
[0009]
6
By executing the automatic boom drive process, the
controller can automatically perform a boom raising operation
or a boom storage operation. Therefore, work of the operator
is facilitated in the boom raising operation or the boom storage
operation. Further, the controller calculates the
displacement distance from the distal end of the boom to the
engaging member, and drives the winch while raising and
lowering the boom such that the calculated displacement
distance is the distance corresponding to the length detected
by the length sensor, or the wire speed calculated based on the
calculated displacement distance is the speed corresponding to
the detected wire speed calculated based on the detected value
of the length sensor. Therefore, the controller can prevent
the wire from being loosened, and can also prevent breakage and
the like in the boom device. Furthermore, since the controller
calculates the displacement distance from the distal end of the
boom to the engaging member based on the specified values stored
in the memory corresponding to the length of the boom and the
position of the engaging member with respect to the derrick
fulcrum of the boom, the specified values read out from the
memory change depending on a type of the boom device, and the
controller can be commonly used with various boom devices.
[0010]
(2) The first drive source may be a telescopic cylinder.
The controller according to the present invention keeps an
extension and retraction speed of the cylinder constant in the
7
automatic boom drive process.
[0011]
Since the controller raises and lowers the boom while
keeping the extension and retraction speed of the cylinder
constant, a target for controlling the drive according to the
displacement distance may be limited to the second drive source.
Accordingly, the controller can easily control the boom device.
Further, since the cylinder is extended and retracted at a
constant speed, a derrick speed of the boom visible to the
operator does not fluctuate little by little, which gives the
operator a sense of security.
[0012]
(3) The controller according to the present invention may
keep an angular velocity of the boom that is raised and lowered
constant in the automatic boom drive process.
[0013]
Since the controller raises and lowers the boom while
keeping the raising and lowering angular velocity of the boom
constant, the target for controlling the drive according to the
displacement distance may be limited to the second drive source.
Accordingly, the controller can easily control the boom device.
Further, since the angular velocity of the boom is constant,
the operator can be given a sense of security as compared with
the case where the angular velocity of the boom fluctuates
little by little according to the displacement distance.
[0014]
8
(4) The controller according to the present invention may
keep a rotation speed of the winch constant in the automatic
boom drive process.
[0015]
Since the controller keeps the rotation speed of the winch
constant, the target for controlling the drive according to the
displacement distance may be limited to the first drive source.
Accordingly, the controller can easily control the boom device.
[0016]
(5) The boom device may further include a tension sensor
configured to detect tension applied to the wire. The memory
stores in advance a threshold for determining an allowable
range of a difference between the displacement distance and the
unwinding length of the wire detected by the length sensor. In
the automatic boom drive process, the controller drives the
winch while raising and lowering the boom between the lowered
position and the raised position such that the difference
between the displacement distance and the length detected by
the length sensor is equal to or less than the threshold. The
controller corrects the threshold according to a magnitude of
the tension detected by the tension sensor.
[0017]
For example, when the tension detected by the tension sensor
is too large, the threshold is corrected so that the tension
becomes small. When the tension detected by the tension sensor
is too small, the threshold is corrected so that the threshold
9
becomes large.
[0018]
(6) The controller according to the present invention may
further execute a determination process of determining whether
the difference between the displacement distance and the
unwinding length of the wire is within a safe value range, and
may further execute a drive stop process of stopping the drive
of the first drive source and the second drive source upon
determining that the difference between the displacement
distance and the unwinding length is not within the safe value
range.
[0019]
The controller stops the drive of the first drive source and
the second drive source upon determining that the difference
between the displacement distance and the unwinding length is
not within the safe value range. That is, when a problem occurs
in winding of the wire by the winch, raising and lowering of
the boom and rotation of the winch are stopped. Accordingly,
it is possible to prevent the boom device and the wire from being
hindered.
[0020]
(7) The specified values may be the length of the boom and
a separation distance between the derrick fulcrum of the boom
and the engaging member.
[0021]
(8) The specified values may be the length of the boom, a
10
first separation distance in a horizontal direction between the
derrick fulcrum of the boom and the engaging member, and a
second separation distance in a vertical direction between the
derrick fulcrum of the boom and the engaging member.
[0022]
(9) The memory may store a class that generates a function
for calculating the displacement distance based on the derrick
angle and the unwinding length of the wire. The controller
according to the present invention generates the function based
on the class by using the specified values read out from the
memory.
[0023]
The controller uses a class to generate a function.
Therefore, the controller can easily generate a function
corresponding to the type of the boom device.
[0024]
(10) The present invention can also be regarded as a boom
device provided with the above-mentioned controller.
[0025]
(11) The present invention can also be regarded as a crane
vehicle including a boom device provided with the
above-mentioned controller and a traveling body mounted with
the boom device.
Advantageous Effects of Invention
[0026]
11
According to the present invention, it is possible to
provide a controller that can automatically store or raise a
boom and can be commonly used for various boom devices.
Brief Description of Drawings
[0027]
[Figure 1] Figure 1 is a schematic diagram of a crane vehicle
10 according to the present embodiment, showing a state where
a boom 32 is at a storage position.
[Figure 2] Figure 2 is a diagram showing the crane vehicle
10 in a state where a boom 42 is at a raised position.
[Figure 3] Figure 3 is a functional block diagram of the
crane vehicle 10.
[Figure 4] Figure 4 is a flowchart of a boom raising process.
[Figure 5] Figure 5 is a flowchart of a boom storage process.
[Figure 6] Figure 6 is an explanatory diagram illustrating
a displacement distance X(θ).
[Figure 7] Figure 7 is another explanatory diagram
illustrating the displacement distance X(θ).
Description of Embodiments
[0028]
Hereinafter, a preferred embodiment of the present
invention will be described with reference to the drawings as
appropriate. Needless to say, the present embodiment is
merely one aspect of the present invention, and the embodiments
12
may be changed without changing the gist of the present
invention.
[0029]
Figure 1 is a schematic diagram showing a crane vehicle 10
according to the present embodiment. The crane vehicle 10
mainly includes a traveling body 11, a boom device 12 mounted
on the traveling body 11, and a cabin 13.
[0030]
The traveling body 11 includes a vehicle body 20, axles 21,
an engine 22 (Figure 4), and a battery 23 (Figure 4).
[0031]
The vehicle body 20 rotatably supports the axles 21. Wheels
are attached to both ends of the axles 21. The engine 22
rotates and drives the axles 21. The engine 22 charges the
battery 23.
[0032]
The engine 22 drives an oil hydraulic pump (not shown)
included in an oil hydraulic supply device 24 described later.
The oil hydraulic pump discharges operating oil at a
predetermined pressure and drives a swivel motor 25, a derrick
cylinder 36, a telescopic cylinder 37, and an oil hydraulic
motor 38 that are shown in Figure 4 and other actuators
(hereinafter, also referred to as the swivel motor 25 and the
like).
[0033]
The vehicle body 20 is mounted with the oil hydraulic supply
13
device 24 shown in Figure 4. The oil hydraulic supply device
24 includes a solenoid valve and the like. The solenoid valve
is opened and closed by a drive signal input from a controller
50 (Figure 4) described later. The swivel motor 25 and the like
are driven by opening and closing the solenoid valve. That is,
the controller 50 controls the drive of the swivel motor 25 and
the like by outputting a drive signal for opening and closing
the solenoid valve. In the present embodiment, an example in
which the swivel motor 25 and the like are oil hydraulic
actuators is described, and all or a part of the swivel motor
25 and the like may be an electric actuator or the like.
[0034]
As shown in Figure 1, the cabin 13 is mounted on a swivel
base 31 of the boom device 12. The cabin 13 includes a driving
device 14 (Figure 3) configured to drive the crane vehicle 10,
and a manipulating device 15 (Figure 3) configured to
manipulate the boom device 12. That is, the crane vehicle 10
is a rough terrain crane, and driving of the crane vehicle 10
and manipulating of the boom device 12 are performed in one
cabin 13. However, the crane vehicle 10 may be an all-terrain
crane including two cabins, that is, a cabin including the
driving device 14 and a cabin including the manipulating device
15.
[0035]
The manipulating device 15 includes an operation lever, an
operation button, and the like for operating the boom device
14
12. The manipulating device 15 outputs an operation signal
indicating a direction and an amount of operation of the
operation lever and an operation signal indicating whether the
operation button is operated. The operation signal output by
the manipulating device 15 is input to the controller 50 (Figure
3).
[0036]
The cabin 13 includes a control box (not shown). The
control box includes a control board. The control board is
mounted with a microcomputer, a resistor, a capacitor, a diode,
and various ICs, and constitutes the controller 50 and a power
supply circuit 17 shown in Figure 3.
[0037]
As shown in Figure 1, the boom device 12 includes the swivel
base 31 rotatably supported by the vehicle body 20 and a boom
32 supported by the swivel base 31. The boom 32 includes a
proximal boom 33, one or more intermediate booms 34, and a
distal boom 35. The proximal boom 33, the intermediate boom
34, and the distal boom 35 are arranged in a nested manner, and
the boom 32 is telescopic. The proximal boom 33 is supported
by the swivel base 31 such that the proximal boom 33 can be
raised and lowered. That is, the boom 32 can be raised and
lowered and is telescopic. The swivel base 31 corresponds to
the “base” in the claims of the present invention.
[0038]
The boom 32 is extended and retracted from a retracted state
15
shown in Figure 1 to an extended state (not shown). The boom
32 is raised and lowered from a lowered position shown in Figure
1 to a raised position shown in Figure 2. The crane vehicle
10 travels in a storage state where the boom 32 is in the
retracted state and at the lowered position.
[0039]
As shown in Figure 3, the boom device 12 further includes
the swivel motor 25, the derrick cylinder 36 configured to raise
and lower the boom 32, and the telescopic cylinder 37 configured
to extend and retract the boom 32.
[0040]
The swivel motor 25 is provided on the vehicle body 20. The
swivel motor 25 is rotated by being supplied with the operating
oil from the oil hydraulic supply device 24 so as to swivel the
swivel base 31.
[0041]
The derrick cylinder 36 is provided on the swivel base 31.
The telescopic cylinder 37 is provided on the boom 32. The
derrick cylinder 36 and the telescopic cylinder 37 are extended
and retracted by being supplied with the operating oil from the
oil hydraulic supply device 24. The derrick cylinder 36 that
is extended and retracted raises and lowers the boom 32. The
telescopic cylinder 37 that is extended and retracted extends
and retracts the boom 32. A swivel joint (not shown) is
provided between the vehicle body 20 and the swivel base 31.
The oil hydraulic supply device 24 provided on the vehicle body
16
20 supplies the operating oil to the derrick cylinder 36 and
the telescopic cylinder 37 via the swivel joint. The derrick
cylinder 36 corresponds to the “first drive source” and the
“cylinder” in the claims of the present invention.
[0042]
The boom device 12 further includes the oil hydraulic motor
38, a winch 39, a load hook 40, and an engaging member 41. The
oil hydraulic motor 38 is rotated by being supplied with the
operating oil from the oil hydraulic supply device 24 via the
swivel joint. A rotation speed of the oil hydraulic motor 38
is controlled by the controller 50. The rotating oil hydraulic
motor 38 rotates a wire drum 29 of the winch 39. The rotating
wire drum 29 winds up a wire 42 or unwinds the wire 42. The
oil hydraulic motor 38 corresponds to the “second drive source”
in the claims of the present invention.
[0043]
The wire 42 is connected to the load hook 40. The load hook
40 is suspended by the wire 42 from a distal end of the boom
32. The load hook 40 rises and falls as the winch 39 rotates.
[0044]
The engaging member 41 is a member that engages with the load
hook 40 to fix the load hook 40. The engaging member 41 is fixed
to the swivel base 31. The engaging member 41 is located right
below the distal end of the boom 32 at the raised position and
in the retracted state. The engaging member 41 fixes the load
hook 40 such that the load hook 40 does not move while the crane
17
vehicle 10 is traveling.
[0045]
The boom 32 further includes a length sensor 26 configured
to detect an unwinding length of the wire 42, and a derrick angle
sensor 27 configured to detect a derrick angle of the boom 32.
A tension sensor 28 shown in Figure 3 will be described in a
modified example.
[0046]
The length sensor 26 and the derrick angle sensor 27 are used
for a boom raising process and a boom storage process which will
be described later.
[0047]
The length sensor 26 is, for example, a rotary encoder
configured to detect an amount of rotation of the winch 39. The
length sensor 26 outputs a pulse signal whose voltage value
changes according to rotation of the winch 39. The length
sensor 26 is connected to the controller 50 by a signal line
such as a cable. The controller 50 calculates the unwinding
length of the wire 42 based on the number of pulses input from
the length sensor 26. However, any kind of sensor may be used
for the length sensor 26 as long as the sensor can detect the
unwinding length of the wire 42.
[0048]
Existing optical or magnetic sensors that output a voltage
value corresponding to the derrick angle of the boom 32 and
rotary encoders are used as the derrick angle sensor 27. The
18
derrick angle sensor 27 is connected to the controller 50 by
a signal line such as a cable. The controller 50 calculates
the derrick angle of the boom 32 based on a signal voltage output
by the derrick angle sensor 27. For example, the controller
50 calculates the derrick angle of the boom 32 with reference
to a position of the boom 32 at a storage position. In the
following, the derrick angle of the boom 32 calculated by the
controller 50 is also referred to as a “detected derrick angle”.
[0049]
The power supply circuit 17 is a circuit configured to
generate electric power to be supplied to the controller 50 and
the like. The power supply circuit 17 is, for example, a DC-DC
converter. The power supply circuit 17 converts a DC voltage
supplied from the battery 23 into a DC voltage having a
predetermined stable voltage value and outputs the DC voltage.
[0050]
The controller 50 includes a central processing unit 51 (CPU)
and a memory 52. The memory 52 includes, for example, a ROM,
a RAM, an EEPROM and the like.
[0051]
The memory 52 stores an operating system 53 (OS), a control
program 54 for controlling the drive of the boom device 12,
specified values, a first threshold, a second threshold, and
a safe value. The OS 53 and the control program 54 are executed
by the CPU 51 in a pseudo-parallel manner by a multi-task
process.
19
[0052]
The specified values refer to “L”, “D”, and “φ” shown in
Figure 6. “L” is the length of the boom 32 from a proximal end
to the distal end. The proximal end of the boom 32 is a position
of the derrick fulcrum P of the boom 32. The distal end of the
boom is, for example, a mounting position of a member around
which the wire 42 is wound. “D” is a distance from the derrick
fulcrum P of the boom 32 to the load hook 40. “φ” is a
depression angle of the load hook 40 with respect to the derrick
fulcrum P of the boom 32. The specified values are stored in
the memory 52 in advance according to the type of the boom device
12. “D” corresponds to the “separation distance” in the claims
of the present invention.
[0053]
The first threshold, the second threshold, and the safe
value are used for a determination process in the boom raising
process and the boom storage process which will be described
later. Details will be described later. The first threshold
and the second threshold correspond to the “threshold” in the
claims of the present invention.
[0054]
The CPU 51, the memory 52, the above-mentioned length sensor
26, the derrick angle sensor 27, and the like are connected to
a communication bus (not shown). The control program 54
executed by the CPU 51 reads a function, the first threshold,
and the second threshold from the memory 52 through the
20
communication bus, receives a detected signal output from the
length sensor 26 and the derrick angle sensor 27, and writes
and stores information and data in the memory 52.
[0055]
The control program 54 has a class. That is, the class is
stored in the memory 52. The class creates an instance
(object). Specifically, the class generates a function X(θ)
as an instance by being given the specified values stored in
the memory 52. The function X(θ) is a calculation formula for
calculating a displacement distance X(θ) {θ: detected derrick
angle}, which is a distance from the distal end of the boom 32
to the load hook 40, using the detected derrick angle θ of the
boom 32. The control program 54 feedback-controls the drive
of the boom device 12 such that a difference between the
displacement distance X(θ) and an unwinding length S of the wire
42 detected by the sensor 26 is equal to or larger than the first
threshold and less than the second threshold. Details will be
described later. The method for generating the function X(θ)
is not limited to those using a class. Other methods may be
used as long as the method can generate the function X(θ) based
on the specified values.
[0056]
The control program 54 is a program for executing the boom
raising process of automatically raising the boom 32 stored in
the storage state (Figure 1) to the raised position (Figure 2)
and the boom storage process of automatically lowering the boom
21
32 at the raised position to the storage state to storage the
boom 32. The boom raising process is an example of an automatic
boom drive process. The boom storage process is an example of
the automatic boom drive process.
[0057]
More specifically, after the crane vehicle 10 arrives at a
work site, an operator makes the control program 54 execute the
boom raising process. That is, the boom raising process is a
process executed for the crane vehicle 10 to start a work at
the work site.
[0058]
The operator makes the control program 54 execute the boom
storage process so that the crane vehicle 10 travels away from
the work site. That is, the boom storage process is a process
executed for the crane vehicle 10 to complete the work at the
work site.
[0059]
The boom raising process is a process in which the control
program 54 automatically performs a raising operation of the
boom 32, which has been manually performed by the operator using
the manipulating device 15. The boom storage process is a
process in which the control program 54 automatically performs
a storage operation of the boom 32, which has been manually
performed by the operator using the manipulating device 15.
Hereinafter, the boom raising process and the boom storage
process will be described in detail with reference to Figures
22
4 and 5. An execution order of steps executed by the control
program 54 in the boom raising process and the boom storage
process may be changed as long as the execution order does not
change the gist of the present invention.
[0060]
After the crane vehicle 10 arrives at the work site, the
operator uses the manipulating device 15 to perform an
operation instructing execution of the boom raising process.
As shown in Figure 1, when the crane vehicle 10 arrives at the
work site, the boom 32 is retracted and lowered down, and the
load hook 40 is fixed to the engaging member 41. The boom
raising process is executed with the load hook 40 fixed to the
engaging member 41 such that the load hook 40 does not move in
the boom raising process.
[0061]
The control program 54 starts to execute the boom raising
process shown in Figure 4 in response to input of an operation
signal instructing the execution of the boom raising process
from the manipulating device 15. First, the control program
54 extends the derrick cylinder 36 at a constant speed (S11).
Alternatively, the control program 54 extends the derrick
cylinder 36 such that the boom 32 is raised at a constant angular
velocity (dθ/dt = constant). More specifically, the control
is more complicated if the control program 54 has two drive
systems to be subjected to feedback control. The control
program 54 extends the derrick cylinder 36 at a constant speed
23
or a constant angular velocity for ease of control. The boom
32 is gradually raised as the derrick cylinder 36 is extended
at a constant speed or a constant angular velocity.
[0062]
Next, the control program 54 rotationally drives the winch
39 at an initial rotation speed V1 (S12). The direction of
rotation of the winch 39 is a direction to which the wire 42
is unwound. That is, the wire 42 is gradually unwound while
the boom 32 is gradually raised.
[0063]
Next, the control program 54 reads the specified values L,
D, and φ from the memory 52, and uses the read specified values
and the class stored in the memory 52 to generate the function
X(θ) that is an instance (S13). Then, the control program 54
differentiates the generated function X(θ) with respect to a
time t, and calculates a time change of the function X (θ), that
is, a unwinding speed V(t) of the wire 42. The differentiation
of the function X(θ) may be performed by a differentiating
circuit using an operational amplifier.
[0064]
Figure 6 shows d(X(θ))/dt obtained by differentiating the
function X(θ) with respect to the time t. “dθ/dt” in the figure
is a time change of the derrick angle θ of the boom 32, that
is, the angular velocity of the boom 32. When the control
program 54 raises the boom 32 at a constant angular velocity,
“dθ/dt” in the figure is a constant. The constant “dθ/dt” is
24
stored in the memory 52 in advance. Further, when the control
program 54 extends the derrick cylinder 36 at a constant speed,
“dθ/dt” is stored in the memory 52 in advance or calculated by
the control program 54. The control program 54 calculates the
unwinding speed V(t) of the wire 42 by using the calculated
“dθ/dt” or “dθ/dt” stored in the memory 52.
[0065]
Next, the control program 54 calculates an unwinding speed
dS/dt of the wire 42 based on the detected signal input from
the length sensor 26 (S15). For example, the control program
54 acquires the detected signals output by the length sensor
26 per unit time, and calculates a differential in the lengths
of the wire 42 indicated by the acquired detected signals. The
differential is the length of the wire 42 per unit time, that
is, the unwinding speed dS/dt of the wire 42. The control
program 53 calculates the actual unwinding speed dS/dt of the
wire 42 by calculating the above-mentioned differential.
[0066]
Then, the control program 54 calculates a difference Z = “V(t)
- dS/dt” between the unwinding speed V(t) of the wire 42
calculated as a calculated value and the actual unwinding speed
dS/dt of the wire 42, and determines whether the calculated Z
is less than the first threshold (S16). That is, in step S16,
whether the unwinding speed of the wire 42 is too high is
determined.
[0067]
25
If the control program 54 determines that Z is less than the
first threshold (S16: Yes), that is, it determines that the
unwinding speed of the wire 42 is too high, the control program
54 reduces a rotation speed of the winch 39 (S17).
Specifically, the control program 54 reduces the rotation speed
of the oil hydraulic motor 38 from the initial value V1
according to the magnitude of the value of Z. In contrast, if
the control program 54 determines that Z is equal to or larger
than the first threshold (S16: No), the control program 54 skips
the process of step S17.
[0068]
Next, the control program 54 determines whether the value
of Z is equal to or larger than the second threshold (S18).
That is, in step S18, whether the unwinding speed of the wire
42 is too low is determined.
[0069]
If the control program 54 determines that the value of Z is
equal to or larger than the second threshold (S18: Yes), that
is, it determines that the unwinding speed of the wire 42 is
too low, the control program 54 increases the rotation speed
of the winch 39 (S19). Specifically, the control program 54
increases the rotation speed of the oil hydraulic motor 38 from
the initial value V1 according to the magnitude of the value
of Z. In contrast, if the control program 54 determines that
the value of Z is less than the second threshold (S18: No), the
control program 54 skips the process of step S19.
26
[0070]
The first threshold and the second threshold are set to
values such that a tension T applied to the wire 42 is less than
a predetermined value and the wire 42 does not loosen in the
process in which the wire 42 is gradually unwound while the boom
32 is gradually raised. That is, the control program 54
feedback-controls the derrick cylinder 36 and the oil hydraulic
motor 38 such that the tension T applied to the wire 42 is less
than the predetermined value and the wire 42 does not loosen.
[0071]
Next, the control program 54 determines whether an absolute
value of Z is less than the safe value stored in the memory 52
(S20). The safe value is a value larger than the first
threshold and the second threshold. That is, in step S20, it
is determined in the winch 39 whether a problem has occurred
in the unwinding of the wire 42 or whether a problem has occurred
in the rotation of the winch 39. The process of step S20
corresponds to the “determination process” in the claims of the
present invention.
[0072]
If the control program 54 determines that the absolute value
of Z is equal to or larger than the safe value stored in the
memory 52 (S20: No), the control program 54 stops driving the
derrick cylinder 36 and the oil hydraulic motor 38 (S21). That
is, the control program 54 stops the boom 32 and the winch 39.
Then, the control program 54 executes a notification process
27
(S22). For example, the control program 54 makes a speaker
output a warning sound, or makes a monitor provided in the
manipulating device 15 display a warning screen. The process
of step S21 corresponds to the “drive stop process” in the
claims of the present invention.
[0073]
Next, the control program 54 determines whether the detected
derrick angle θ is equal to or larger than α (S23). α is a value
of θ when the boom 32 is at the raised position, and is stored
in the memory 52 in advance. That is, in step S23, it is
determined whether the boom 32 has arrived at the raised
position. The control program 54 repeatedly executes the
processes from step S16 to step S20 until the boom 32 arrives
at the raised position and the detected derrick angle θ has
reached α (S23: No).
[0074]
If the control program 54 determines that the boom 32 has
arrived at the raised position and the detected derrick angle
θ has reached α (S23: Yes), the control program 54 stops the
drive of the derrick cylinder 36 and the oil hydraulic motor
38 (S24), and ends the boom raising process.
[0075]
Next, the boom storage process will be described with
reference to Figure 5. The same process as the boom raising
process is given the same step number as the step number
associated with the boom raising process, and the description
28
thereof is omitted.
[0076]
When the operator finishes the work of the crane vehicle 10,
the operator first uses the manipulating device 15 to make the
boom 32 in the retracted state and make the boom 32 at the raised
position as shown in Figure 2. Then, the operator engages the
load hook 40 with the engaging member 41 to fix the load hook
40 with the engaging member 41. After that, the operator uses
the manipulating device 15 to perform an operation instructing
the execution of the boom storage process.
[0077]
The control program 54 starts to execute the boom storage
process shown in Figure 5 in response to input of an operation
signal instructing the execution of the boom storage process
from the manipulating device 15. First, the control program
54 retracts the derrick cylinder 36 at a constant speed (S31).
As the derrick cylinder 36 is retracted at a constant speed,
the boom 32 is gradually lowered.
[0078]
Next, the control program 54 rotationally drives the winch
39 at an initial rotation speed V2 (S32). The direction of
rotation of the winch 38 is a direction to which the wire 42
is wound up. That is, the wire 42 is gradually wound up while
the boom 32 is gradually lowered. The initial rotation speed
V2 may be the same as the initial rotation speed V1 or different
from the initial rotation speed V1.
29
[0079]
Next, the control program 54 executes processes from steps
S13 to S22 in the same manner as the boom raising process. That
is, the control program 54 performs feedback control to
gradually lower the boom 32 and to gradually wind up the wire
42 in a manner such that the tension T applied to the wire 42
is less than a predetermined value and the wire 42 does not
loosen.
[0080]
Next, the control program 54 determines whether the detected
derrick angle θ is equal to or less than β (S33). β is a value
of θ when the boom 32 is at the lowered position, and is stored
in the memory 52 in advance. β is, for example, “0”. That is,
in step S33, it is determined whether the boom 32 has arrived
at the lowered position. The control program 54 repeatedly
executes the processes from steps S16 to S20 until the boom 32
arrives at the lowered position and the detected derrick angle
θ reaches β (S33: No).
[0081]
If the control program 54 determines that the boom 32 has
arrived at the lowered position and the detected derrick angle
θ has reached β (S33: Yes), the control program 54 stops the
drive of the derrick cylinder 36 and the oil hydraulic motor
38 (S24), and ends the boom storage process.
[0082]
[Operation and Effect of Embodiment]
30
[0083]
In the present embodiment, the control program 54 executes
the boom raising process and the boom storage process, so that
the raising operation of the boom 32 and the storage operation
of the boom 32 can be automatically performed. Therefore, the
work of the operator is facilitated in the raising operation
of the boom 32 and the storage operation of the boom 32, and
it is possible to prevent “irregular winding” in the winch 39,
and further, it is possible to prevent the boom device 12 from
being damaged. More specifically, the operator must operate
two operating targets, the boom 32 and the winch 39 when
manually performing the raising operation of the boom 32 and
the storage operation of the boom 32. That is, the operator
operates the winch 39 while the raising and lowering the boom
32 and monitoring a tension state of the wire 42. The operation
requires the mastery skill of the operator. If the operator
makes a mistake in the operation, excessive tension acts on the
wire 42, which may damage the engaging member 41 and the winch
39. Further, if the operator makes a mistake in the operation,
the wire 42 may loosen, causing the “irregular winding” in the
winch 39. In the present embodiment, the control program 54
executes the boom raising process and the boom storage process,
so that the work of the operator is facilitated, and it is
possible to prevent the “irregular winding” from occurring in
the winch 39, and further, it is possible to prevent the boom
device 12 from being damaged.
31
[0084]
The control program 54 generates the function X(θ) using the
specified values stored in the memory 52, and calculates the
displacement distance X(θ) {θ: detected derrick angle} from the
distal end of the boom 32 to the engaging member 41 using the
generated function (θ). Then, the control program 54 performs
feedback control using the calculated displacement distance
X(θ). Therefore, since the specified values read out from the
memory 52 are changed depending on the type of the boom device
12, the controller 50 can be commonly used with various boom
devices 12. Accordingly, the controller 50 with high
versatility can be realized.
[0085]
In the present embodiment, since the control program 54
extends and retracts the derrick cylinder 36 at a constant speed
(S11 and S31), the target of feedback control may be limited
to the oil hydraulic motor 38 of the winch 39. Accordingly,
the control program 54 can easily control the boom device 12.
Further, in the boom 32 which is visible to the operator, if
a derrick speed fluctuates little by little, the operator may
be anxious. In the present embodiment, since the derrick
cylinder 36 is extended and retracted at a constant speed, the
derrick speed of the boom 32 does not fluctuate little by little,
which gives the operator a sense of security.
[0086]
In the present embodiment, the control program 54 stops the
32
boom 32 and the winch 39 upon determining that the absolute
value of the difference between the displacement distance X(θ)
and the unwinding length S of the wire 42 is equal to or larger
than the safe value. Therefore, it is possible to prevent the
boom device 12 from failing or the wire 42 from being damaged.
[0087]
In the present embodiment, the control program 54 generates
the function X(θ) using the specified values L, D, and φ read
out from the memory 52, and the class, and calculates the
displacement distance X(θ) {θ: detected derrick angle} using
the generated function X(θ). Therefore, in step S14, the
displacement distance X(θ) can be calculated without reading
the specified values L, D, and φ from the memory 52. Therefore,
the number of times of reading the specified values L, D, and
φ from the memory 52 can be reduced. Accordingly, the speed
of processes from steps S14 to S19 is increased. Since the
speed of the processes is increased, the feedback control can
be performed in a period shorter than the case when the
specified values L, D, and φ are sequentially read out from the
memory 52 to calculate the displacement distance X(θ).
Accordingly, it is possible to further prevent the “irregular
winding” from occurring in the winch 39, and further prevent
the boom device 12 from being damaged.
[0088]
[Modification]
[0089]
33
In the present modification, an example in which the tension
T applied to the wire 42 is detected and the first threshold
and the second threshold are corrected based on the detected
tension T will be described.
[0090]
The boom device 12 further includes the tension sensor 28
as shown in Figure 3. The tension sensor 28 is a sensor
configured to output a detected signal of the voltage value
corresponding to the tension T applied to the wire 42. The
tension sensor 28 is, for example, a load cell.
[0091]
The tension sensor 28 is connected to the controller 50 by
a signal line such as a cable. The detected signal output by
the tension sensor 28 is input to the controller 50. The
controller 50 determines the tension T applied to the wire 42
by the detected signal input from the tension sensor 28. Then,
the controller 50 corrects or re-determines the first threshold
and the second threshold stored in the memory 52 based on the
determined tension T. Specifically, the memory 52 stores in
advance a correction formula for correcting the first threshold
and the second threshold from the tension T, or a correspondence
table in which the tension T is associated with the first
threshold and the tension T is associated with the second
threshold. The controller 50 corrects or re-determines the
first threshold and the second threshold by using the
determined tension T and the above-mentioned correction
34
formula, or by using the determined tension T and the
above-mentioned correspondence table. Re-determination of
the first threshold and the second threshold is also included
in the correction of the first threshold and the second
threshold.
[0092]
For example, when the tension T detected by the tension
sensor 28 is larger than a first determination value stored in
the memory 52, the second threshold is corrected or
re-determined so that the second threshold becomes small. The
tension T applied to the wire 42 decreases when the second
threshold becomes small. Further, when the tension T detected
by the tension sensor 28 is smaller than a second determination
value stored in the memory 52 and the wire 42 is not sufficiently
stretched, the first threshold is corrected or re-determined
so that the first threshold becomes large. The wire 42 is
stretched with an appropriate tension T when the first
threshold becomes large.
[0093]
The controller 50 executes the determination processes of
step S16 and step S18 by using the corrected or re-determined
first threshold and second threshold. Other processes are the
same as those of the embodiment.
[0094]
[Operation and Effect of Modification]
[0095]
35
In the present modification, the magnitude of the tension
T applied to the wire 42 can be controlled more appropriately
by correcting the first threshold and the second threshold by
the tension of the wire 42 detected by the tension sensor 28.
[0096]
[Other Modifications]
[0097]
In the above-mentioned embodiment, an example in which the
specified values are “L”, “D”, and “φ” has been described.
However, the specified values are not limited to “L”, “D”, and
“φ”. The specified values may be “L”, “φ”, “a”, and “b” as
shown in Figure 7. The specified value “D” can be replaced with
the specified values “a” and “b”. Specifically, “D” can be
replaced with “a” and “b” as “D squared” = “a squared” + “b
squared”. “a” corresponds to the “first separation distance”
in the claims of the present invention. “b” corresponds to the
“second separation distance” in the claims of the present
invention.
[0098]
In the above-mentioned embodiment and modifications, an
example in which “φ” is included in the specified values has
been described. However, “φ” can be excluded from the
specified values with the derrick angle θ used as an elevation
angle from the engaging member 42. That is, “φ” is excluded
from the specified values with θ + φ used as a new θ.
[0099]
36
In the above-mentioned embodiment, an example in which the
derrick cylinder 36 is extended and retracted at a constant
speed in steps S11 and S31 has been described. However, the
drive of the derrick cylinder 36 may be controlled such that
the boom 32 is raised and lowered at a constant speed.
[0100]
In the above-mentioned embodiment, an example in which the
derrick cylinder 36 is extended and retracted at a constant
speed and the oil hydraulic motor 38 of the winch 39 is
feedback-controlled has been described. However, the winch 39
may be rotated at a constant rotation speed, and the derrick
cylinder 36 of the boom 32 may be feedback-controlled.
[0101]
In the above-mentioned embodiment, an example in which the
drive of the winch 39 is feedback-controlled such that the
difference Z between the unwinding speed of the wire 42 and the
actual unwinding speed of the wire 42 detected by the length
sensor 26 is within a range indicated by the second threshold
has been described. However, the drive of the winch 39 may be
feedback-controlled such that the difference between the
unwinding length of the wire 42 and the actual unwinding length
of the wire 42 detected by the length sensor 26 is within the
threshold range. Also in this case, it is possible to prevent
the “irregular winding” from occurring in the winch 39, and
further prevent the boom device 12 from being damaged.
37
Reference Signs List
[0102]
10 crane vehicle
11 traveling body
12 boom device
26 length sensor
27 derrick angle sensor
31 swivel base
32 boom
36 derrick cylinder
38 oil hydraulic motor
39 winch
40 load hook
41 engaging member
42 wire
50 controller
52 memory

38
We Claim:-
[Claim 1]
A controller used for a boom device,
the boom device including
a base,
a boom supported by the base and capable of being raised and
lowered between a lowered position and a raised position,
a winch having a wire wound around a wire drum and wound
around a distal end of the boom,
a load hook provided at a tip of the wire,
a first drive source configured to raise and lower the boom,
a second drive source configured to drive the winch and to
unwind the wire from the wire drum or wind the wire around the
wire drum,
an engaging member provided on the base and to which the load
hook suspended from the distal end of the boom at the raised
position is engaged in a detachable manner,
a derrick angle sensor configured to detect a derrick angle
of the boom, and
a length sensor configured to detect an unwinding length of
the wire from the distal end of the boom,
the controller comprising:
a memory configured to store specified values corresponding
to a length of the boom and a position of the engaging member
with respect to a derrick fulcrum of the boom,
and the controller executes an automatic boom drive process of
39
driving the winch while raising or lowering the boom between
the lowered position and the raising position in a state where
the load hook is engaged with the engaging member based on
derrick angle of the boom detected by the derrick angle sensor
and based on the specified values read out from the memory,
and wherein in the automatic boom drive process of driving,
the controller calculates the displacement distance from the
distal end of the boom to the engaging member, and matches the
displacement distance to a distance corresponding to the length
detected by the length sensor,
or the controller further calculates the wire speed which is
an unwinding speed or a winding speed of wire based on the
displacement distance and matches the calculated wire speed to
a speed corresponding to a detected wire speed calculated based
on a detected value of the length sensor.
[Claim 2]
The controller according to claim 1, wherein
the first drive source is a telescopic cylinder, and
an extension and retraction speed of the cylinder is kept
constant in the automatic boom drive process.
[Claim 3]
The controller according to claim 1, wherein
an angular velocity of the boom that is raised and lowered
is kept constant in the automatic boom drive process.
[Claim 4]
The controller according to claim 1, wherein
40
a rotation speed of the winch is kept constant in the
automatic boom drive process.
[Claim 5]
The controller according to any one of claims 1 to 4, wherein
the boom device further includes a tension sensor configured
to detect tension applied to the wire,
the memory stores in advance a threshold for determining an
allowable range of a difference between the displacement
distance and the unwinding length of the wire detected by the
length sensor,
in the automatic boom drive process, the controller drives
the winch while raising and lowering the boom between the
lowered position and the raised position such that the
difference between the displacement distance and the length
detected by the length sensor is within the threshold range,
and
the controller corrects the threshold according to a
magnitude of the tension detected by the tension sensor.
[Claim 6]
The controller according to any one of claims 1 to 5, wherein
the controller executes a determination process of
determining whether the difference between the displacement
distance and the unwinding length of the wire is within a safe
value range, and
the controller further executes a drive stop process of
stopping the drive of the first drive source and the second
41
drive source in response to determination that the difference
between the displacement distance and the unwinding length is
not within the safe value range.
[Claim 7]
The controller according to any one of claims 1 to 6, wherein
the specified values include
the length of the boom, and
a separation distance between the derrick fulcrum of the
boom and the engaging member.
[Claim 8]
The controller according to any one of claims 1 to 6, wherein
the specified values include
the length of the boom,
a first separation distance in a horizontal direction
between the derrick fulcrum of the boom and the engaging member,
and
a second separation distance in a vertical direction between
the derrick fulcrum of the boom and the engaging member.
[Claim 9]
The controller according to any one of claims 1 to 8, wherein
the memory stores a class that generates a function for
calculating the displacement distance based on the derrick
angle and the unwinding length of the wire, and
the controller generates the function based on the class by
using the specified values read out from the memory.
[Claim 10]
42
A boom device comprising:
the controller according to any one of claims 1 to 9.
[Claim 11]
A crane vehicle comprising:
the boom device according to claim 10; and
a traveling body mounted with the boom device.
Dated this 25th day of January 2022.