FIELD OF THE INVENTION
[0001] The present invention relates to a boom telescoping control unit for controlling
a telescopic motion (extension and retraction) of a telescopic boom having a plurality
of boom members capable of relative displacement to telescopically extend and retract
the boom as described in
JP 2002 332 194 A.
BACKGROUND ART
[0002] Heretofore, there has been known a machine equipped with a telescopic boom, such
as a wheel crane, a rough terrain crane or an all terrain crane. The telescopic boom
comprises a single fixed boom member constituting a base end thereof and a plurality
of movable boom members provided on the side of a distal end of the fixed boom member,
that is, on the side of a boom point. The movable boom members are adapted to be moved
by a hydraulic cylinder (telescopic cylinder) in a telescoping direction (a direction
in which the entire telescopic boom is to be telescopically extended and retracted).
To extend and retract the type of telescopic boom, the member to be driven (hereinafter
referred to as "target boom member") has to be selected among a plurality of movable
boom members constituting the telescopic boom.
[0003] JP 9-2781A discloses a control unit for automatically switching a target boom member among a
plurality of boom members constituting a telescopic boom. This control unit imparts
to the boom members a extending motion sequentially in order from one thereof closest
to a boom foot (this boom member is the thickest or largest-diameter one) for extending
the telescopic boom, while imparting to the boom members a retracting motion sequentially
in order from one thereof closest to a boom point (this boom member is the thinnest
or smallest-diameter one) for retracting the telescopic boom. In this specification,
the predetermined target-boom-member switching sequence for an automatic telescoping
control as described above will be called "regular boom-telescoping sequence", and
the displacement amount of each of the movable boom members in an extension direction
when the movable boom members are moved in the regular boom-telescoping sequence (the
details will be described later) will be called "regular extension amount".
[0004] While the automatic telescoping control as described above is effective for a normal
crane operation, it is desirable to allow an operator performing maintenance, repair
or the like of the telescopic boom to manually select the target boom member, i.e.,
select one of the movable boom members to be driven. As a control unit for realizing
such manual selection of the target boom member, there may be imagined a device capable
of performing both of an automatic telescoping control for automatically moving the
movable boom members in the telescoping direction according to the regular boom-telescoping
sequence and an individual telescoping control for driving only one of the movable
boom members manually selected by an operator, in the telescoping direction, while
allowing the two telescoping controls to be manually and selectively switched.
[0005] The thus imagined control unit, however, would have a problem of difficulty in switching
the control from the individual telescoping control into the automatic telescoping
control. Since the individual telescoping control involves operations of the respective
movable boom members in an irregular sequence different from the regular boom-telescoping
sequence and the movable boom members intend to have their respective actual extension
amount different from a regular extension amount thereof, the shift from the individual
telescoping control to the automatic telescoping control cannot be performed immediately
upon the selection of the automatic telescoping control by an operator. Particularly,
in a crane equipped with the above telescopic boom and a moment limiting device for
limiting a movement of the telescopic boom based on a preset crane capacity, the shift
from the individual telescoping control to the automatic telescoping control may make
it difficult to ensure the safety by the moment limiting device. Specifically, because
the crane capacity is generally set on an assumption that each of the movable boom
members has a regular extension amount, the crane operation in an irregular telescoping
state where each of the movable boom members has a displacement amount different from
the regular extension amount may prevent the moment limiting device from adequate
limitation of the movement of the telescopic boom.
DISCLOSURE OF THE INVENTION
[0006] It is an object of the present invention to provide a boom telescoping control unit
capable of both of an automatic telescoping control for a telescopic boom comprising
a plurality of movable boom members and an individual telescoping control of each
of the movable boom members based on a manual selection thereof, while allowing the
shift from the individual telescoping control to the automatic telescoping control
to be performed in an easy and safe manner.
[0007] To achieve the above object, the present invention provides a boom telescoping control
unit for controlling a telescopic motion of a telescopic boom having a plurality of
movable boom members capable of relative displacement to each other to extend and
retract the entire telescopic boom. The control unit comprises: automatic telescoping
control means operative to determine a target boom member to be telescopically moved
from the movable boom members sequentially and make only the selected movable member
as the target member to be moved so as to sequentially make the movable boom members
be moved in a telescoping direction of the telescopic boom according to a predetermined
regular boom-telescoping sequence to automatically extend and retract the telescopic
boom; individual telescoping control means operative to make only a manually selected
one of the movable boom members be moved, individually, in the telescoping direction
of the telescopic boom; control switching means including a selector switch for selecting
a telescoping control from an automatic telescoping control performed by the automatic
telescoping control means and an individual telescoping control performed by the individual
telescoping control means, the control switching means being operative to switch the
telescoping control to be performed between the automatic telescoping control and
the individual telescoping control; automatic-telescoping-control switching prohibition
means operative to make a prohibition against switching from the individual telescoping
control to the automatic telescoping control irrespective of the selection by the
selector switch, on condition that the movable boom members have been moved in a sequence
different from the regular boom-telescoping sequence when the telescoping control
selected by the selector switch is switched from the individual telescoping control
to the automatic telescoping control; and switching-prohibition release means operative
to release the prohibition by the control switching prohibition means at the time
when the entire telescopic boom is brought into a maximally retracted state or an
maximally extended state.
[0008] The above "regular boom-telescoping sequence" is preferably a sequence in which the
movable boom members are moved in an extending direction in order from the movable
boom member closest to a boom foot, that is, closest to a base end of the telescopic
boom, to the movable boom member closest to a boom point, that is, closest to a distal
end of the telescopic boom, for extending the telescopic boom while the movable boom
members are moved in a retracting direction in order from the movable boom member
closest to the boom point to the movable boom member closest to the boom foot for
retracting the telescopic boom.
[0009] In the boom telescoping control unit of the present invention, the telescoping control
for the telescopic boom is prevented from being switched from the individual telescoping
control to the automatic telescoping control under a condition that the actual extension
amount of any one of the movable boom members is inadequate for the automatic telescoping
control. Specifically, in the case that the movable boom members have been moved in
a sequence different from the regular boom-telescoping sequence in the individual
telescoping control, which may make at least one of the actual extension amounts of
the respective movable boom members be different from a regular extension amount thereof
as mentioned above, the automatic-telescoping-control switching prohibition means
makes a prohibition against switching the telescoping control to the automatic telescoping
control, even if the automatic telescoping control is selected by the selector switch.
[0010] On the other hand, in the case that the entire telescopic boom have been brought
into the maximally retracted state or the maximally extended state, which certainly
makes the actual extension amount of each of the movable boom members be equal to
the regular extension amount even during the performance of the individual telescoping
control, the prohibition against the switching to the automatic telescoping control
is released by the switching-prohibition release means. In other words, only a trouble-free
control switching is automatically permitted.
[0011] Operators normally select the automatic telescoping control for a crane operation.
Accordingly, the prohibition against switching to the automatic telescoping control
in the above manner inhibits the operators from performing the crane operation under
an unsuitable condition that the telescopic boom is irregularly telescoped, i.e.,
under a condition that each of the movable boom members may have an actual extension
amount different from the regular extension amount. This provides enhanced safety
in operation.
[0012] The switching-prohibition release means may release the prohibition against switching
to the automatic telescoping control not only in the case that the entire telescopic
boom have been brought into the maximally retracted state or the maximally extended
state, but also in another condition for preventing problem from occurring due to
switching to the automatic telescoping control. For example, it is permitted that
the boom telescoping control unit of the present invention may comprise extension-amount
storage means operative to store therein respective actual extension amounts of the
movable boom members, and the switching-prohibition release means is operative to
release the prohibition on condition that the actual extension amounts stored in the
extension-amount storage means become equal to their respective regular extension
amounts which are assumed extension amounts of the respective movable boom members
when the movable boom members have been telescopically moved in the regular boom-telescoping
sequence.
[0013] The thus configured switching-prohibition release means releases the prohibition
as long as the movable boom members have their respective regular extension amounts,
even if the telescopic boom is not maximally retracted or extended. This allows the
prohibition to be released, with no problem, in a shorter time as compared with the
case where the prohibition against switching to the automatic telescoping control
is not released except the condition that the telescopic boom is maximally retracted
or extended.
[0014] The release of the prohibition in the above configuration is performed not only in
the case that the plurality of movable boom members are actually moved in the regular
boom-telescoping sequence, but also in the case that the movable boom members are
moved in a sequence different from the regular boom-telescoping sequence but their
movements eventually let the actual extension amount of each of the movable boom members
be equal to the regular extension amount.
[0015] The boom telescoping control unit of the present invention can be used suitably also
in a crane comprising a moment limiting device adapted to set an allowable value of
a hoisting load of the telescopic boom so as to limit a tipping moment produced by
a weight of the telescopic boom itself and the hoisting load. In this case, it is
preferable that the boom telescoping control unit further comprises crane-capacity
limiting means operative to make the moment limiting device set the allowable value
of the hoisting load to a lower level, when the prohibition against switching to the
automatic telescoping control is made, than a level of the hoisting load when the
prohibition is not made. The crane-capacity limiting means lowers the allowable value
of the hoisting load set by the moment limiting device under the condition that the
prohibition against switching to the automatic telescoping control is made, that is,
in a situation where at least one of the movable boom members has an irregular extension
amount different from the regular extension amount to thereby make it difficult to
estimate the tipping moment, thus enhancing safety in crane operation by the crane.
[0016] The present invention also provides a crane having a telescopic boom, the crane comprising:
a hydraulic circuit for driving the telescopic boom; a moment limiting device adapted
to set an allowable value of a hoisting load for the telescopic boom so as to limit
an tipping moment produced by a weight of the telescopic boom itself and the hoisting
load; and a boom telescoping control unit adapted to input a control signal into the
hydraulic circuit as defined in the appended claim 5, the crane-capacity limiting
means of the boom telescoping control unit being operative to make the moment limiting
device set the allowable value of the hoisting load to a lower level, when the prohibition
against switching to the automatic telescoping control is made, than a level of the
hoisting load when the prohibition is not made.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
FIG. 1 is a schematic diagram showing a telescopic boom and a hydraulic circuit associated
with a control unit of the present invention.
FIG. 2 is an electrical block diagram showing various signals to be input into and
output from the control unit to control the hydraulic circuit in FIG. 1.
FIG. 3 is a flowchart showing a routine of the control by the control unit according
to a first embodiment of the present invention
FIG. 4 is a flowchart showing a subroutine of an automatic telescoping control in
the control routine in FIG. 3.
FIG. 5 is a flowchart showing a control routine in a control unit according to a second
embodiment of the present invention.
FIG. 6 is a flowchart showing a control routine in a control unit according to a third
embodiment of the present invention.
FIG. 7 is a flowchart showing a control routine in a control unit according to a fourth
embodiment of the present invention.
FIG. 8 is a flowchart showing an automatic telescoping control subroutine in the control
routine in FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] There will be explained various embodiments according to the invention with reference
to the drawings. The following embodiments are applied in common to a crane which
comprises a telescopic boom 10 shown in FIG. 1 and a telescopic drive mechanism for
telescopically driving the telescopic boom 10. In other words, the crane is provided
with a boom telescoping control unit according to the present invention, namely, a
control unit 40.
[0019] The telescopic boom 10 is a box-shaped boom, for example, used in a crane, comprising
a plurality of boom members telescopically arranged. Specifically, the telescopic
boom 10 comprises a single fixed boom member 11, which is a member on the side of
a boom foot which is positioned at a base end of the telescopic boom 10 and mounted
to a crane body not shown (the fixed boom member 11 is also called "base boom member"
or "first boom member"), and a movable boom member assembly 12 provided on the side
of a distal end of the fixed boom member 11, that is, on the side of a boom point
which is positioned at a distal end of the telescopic boom 10. The movable boom member
assembly 12 includes a plurality of movable boom members. The specific number of movable
boom members according to the invention is not limited. The movable boom member assembly
12 shown in FIG. 1 comprises a second boom member 12b, a third boom member 12c, a
fourth boom member 12d and a fifth boom member 12e, which are arranged in this order
from the boom foot to the boom point of the telescopic boom 10.
[0020] The telescopic drive mechanism includes a first telescopic cylinder 16, a second
telescopic cylinder 18, and a hydraulic circuit 20. The first and second telescopic
cylinders 16 and 18 are connected to the movable boom members to move the movable
boom member assembly 12 in a telescoping direction. In other words, the telescopic
boom 10 shown in FIG. 1 is telescopically driven in a two-step manner.
[0021] The first telescopic cylinder 16 is adapted to move the second boom member 12b and
the third boom member 12c of the movable boom member assembly 12. Specifically, the
first telescopic cylinder 16 has a base portion 16c, an intermediate portion 16b adapted
to be axially telescoped with respect to the base portion 16c, and a head portion
16a adapted to be axially telescoped with respect to the intermediate portion 16b;
the head portion 16a, the intermediate portion 16b and the head portion 16c are coupled
to the fixed boom member 11, the second boom member 12b and the third boom member
12c, respectively.
[0022] Similarly, the second telescopic cylinder 18 is adapted to move the fourth boom member
12d and the fifth boom member 12e of the movable boom member assembly 12. Specifically,
the second telescopic cylinder 18 has a base portion 18e, an intermediate portion
18d adapted to be axially telescoped with respect to the base portion 18e, and a head
portion 18c adapted to be axially telescoped with respect to the intermediate portion
18d; the head portion 18c, the intermediate portion 18d and the head portion 18e are
coupled to the third boom member 12c, the fourth boom member 12d and the fifth boom
member 12e, respectively.
[0023] The hydraulic circuit 20 is adapted to supply hydraulic fluid to the first and second
telescopic cylinders 16 and 18 to impart a telescopic motion to each of the movable
boom members comprised in the movable boom member assembly 12, i.e., to extend and
retract the first and second telescopic cylinders 16 and 18. Specifically, the hydraulic
circuit 20 comprises: a tank 20T which reserves hydraulic fluid; a hydraulic pump
20P adapted to discharge therefrom the hydraulic fluid reserved in the tank 20T; a
extension/retraction selector valve 21 connected to a downstream side of the hydraulic
pump 20P (the downstream side of the hydraulic pump 20P will hereinafter be referred
to generally as "downstream side"); a cylinder selector valve 22 provided on a downstream
side of the extension/retraction selector valve 21; and first and second cylinder-telescoping
control valves 26 and 28 each connected to a downstream side of the cylinder selector
valve 22, the first and second telescopic cylinders 16 and 18 being connected to respective
downstream sides of the first and second cylinder-telescoping control valves 26 and
28. The first and second cylinders 16 and 18 discharge return fluid, which is returned
to the tank 20T through the extension/retraction selector valve 21.
[0024] The extension/retraction selector valve 21 is adapted to switch an fluid passage
between the hydraulic pump 20P and the cylinder selector valve 22 so as to allow a
movement direction of the first telescopic cylinder 16 or the second telescopic cylinder
18 to be selected between an extension direction and a retraction direction. The cylinder
selector valve 22 is adapted to switch an fluid passage on the downstream side of
the extension/retraction selector valve 21 between a passage for leading hydraulic
fluid from the extension/retraction selector valve 21 to the first cylinder-telescoping
control valve 26 and a passage for leading the hydraulic fluid to the second cylinder-telescoping
control valve 28. The first cylinder-telescoping control valve 26 is adapted to switch
an fluid passage from the cylinder selector valve 22 to the first telescopic cylinder
16 between a passage for moving the intermediate portion 16b of the first telescopic
cylinder 16 and a passage for moving the head portion 16a of the first telescopic
cylinder 16. Similarly, the second cylinder-telescoping control valve 28 is adapted
to switch an fluid passage from the cylinder selector valve 22 to the second telescopic
cylinder 18 between a passage for moving the intermediate portion 18d of the second
telescopic cylinder 18 and a passage for moving the head portion 18c of the second
telescopic cylinder 18.
[0025] The control unit 40 controls the driving of the telescopic boom 10 by the first and
second hydraulic cylinders 16 and 18 and the hydraulic circuit 20. Specifically, the
control unit 40 is operative to input after-mentioned control signals 21 s, 22s, 26s
and 28s into the extension/retraction selector valve 21, the cylinder selector valve
22, the first cylinder-telescoping control valve 26 and the second cylinder- telescoping
control valve 28 included in the hydraulic circuit 20, respectively, to thereby control
supply/discharge of the hydraulic fluid to/from each of the first and second hydraulic
cylinders 16 and 18, thus controlling the telescoping operation of the telescopic
boom 10.
[0026] The control unit 40 has an automatic telescoping control section 41, an individual
telescoping control section 42, a control switching section 45, an automatic-telescoping-control
switching prohibition section 43, and a switching-prohibition release section 44,
as shown in FIG. 3. While details of each operation of the sections will be described
later, an outline thereof is as follows.
[0027] The automatic telescoping control section 41 is operative to perform an automatic
telescoping control for sequentially making the boom members 12b to 12e of the movable
boom member assembly 12 be moved, in a telescoping direction of the telescopic boom
10, according to a predetermined regular boom-telescoping sequence to automatically
and telescopically move the telescopic boom.
[0028] The individual telescoping control section 42 is operative to perform an individual
telescoping control for moving only a manually selected one of the boom members 12b
to 12e, individually, in the telescoping direction of the telescopic boom 10.
[0029] The control switching section 45, which constitutes "control switching means" set
forth in the appended claims, in cooperation with an after-mentioned control selector
switch 32, is operative to fundamentally switch the boom telescoping control by the
control unit 40 to the selected one from the automatic telescoping control and the
individual telescoping control by the control selector switch 32.
[0030] The switching-prohibition section 43 is operative to make a prohibition against switching
from the individual telescoping control to the automatic telescoping control, irrespective
of the selection by the selector switch 32, on condition that the movable boom members
of the telescopic boom 10 have been operated in a sequence different from the regular
boom-telescoping sequence when the control selected by the selector switch 32 is switched
from the individual telescoping control to the automatic telescoping control.
[0031] The switching-prohibition release section 44 is operative to release the prohibition
by the control switching prohibition section 43 at the time when the entire telescopic
boom has been brought into a state of maximal retraction or maximal extension.
[0032] FIG. 2 is a block diagram showing a signal to be input into the control unit 40 and
a signal to be output from the control unit 40.
[0033] The crane provided with the control unit 40 comprises a boom-telescoping manual operating
device 31, a telescoping-control selector switch 32, a telescoping-target switching
permission switch 33, telescopic-boom-length detection means 36, load detection means
37 and a moment limiting device 38, each of which is connected to the control unit
40.
[0034] The boom-telescoping manual operating device 31 inputs a telescoping command signal
for commanding to extend or retract the telescopic boom 10 (see FIG. 1), into the
control unit 40. The boom-telescoping manual operating device 31 has a control lever
and a circuit for generating a command signal depending on an operation direction
of the control lever, being operative to input a boom-extension command signal 31
a into the control unit 40 corresponding to the operation of the control lever in
an extension direction and input a boom-retraction command signal 31b into the control
unit 40 corresponding to the operation of the control lever in a retraction direction.
The control unit 40 is operative to input a switching signal 21 for telescoping of
the telescopic boom 10 into the extension/retraction selector valve 21 to operate
the extension/retraction selector valve 21, based on the command signal input from
the boom-telescoping manual operating device 31.
[0035] The control selector switch 32, which is provided in a crane cab (not shown), is
to be manually operated to select a boom telescoping control to be executed by the
control unit 40 from the automatic telescoping control performed by the automatic
telescoping control section 41 and the individual telescoping control performed by
the individual telescoping control section 42.
[0036] The control selector switch 32 is operated by an operator for manually selecting
one from five items: "automatic telescoping", "2nd boom member", "3rd boom member",
"4th boom member" and "5th boom member". Furthermore, the control selector switch
32 inputs an automatic-telescoping-control selection signal 32a into the control unit
40 when the "automatic telescoping" is selected while inputs an individual-telescoping-control
selection signal 32b, upon selection of the "n th boom member (where n is an integer
of 2 to 5)", for imparting a telescopic motion to only the selected boom member (movable
boom member) into the control unit 40.
[0037] The telescoping-target switching permission switch 33 is manually operated by an
operator to permit, following the finish of a telescopic motion of one of the movable
boom members of the movable boom member assembly 12 during the automatic telescoping
control, the next one of the boom members to start its telescopic motion. The telescoping-target
switching permission switch 33 is provided, for example, to a top (not shown) of the
control lever of the boom-telescoping manual operating device 31, so as to allow an
operator to push it while manually operating the control lever, and input a permission
signal 33a into the control unit 40 in response to the pushing operation.
[0038] Thus, the automatic telescoping control in this embodiment is not a full-automatic
control of automatically moving all of the movable boom members in a continuous manner,
irrespective of operator's intention, but a so-called semi-automatic control of waiting
the finish of the telescopic motion of each of the movable boom members and the input
of the permission signal 33a, thereafter, for permitting the telescopic motion of
the next movable boom member and starting telescopically moving it following the input
of the permission signal 33a. Meanwhile, the present invention includes another embodiment
with the full-automatic telescoping control. In this embodiment, the telescoping-target
switching permission switch 33 can be omitted, and each of the movable boom members
are automatically and telescopically moved in a continuous manner based on only the
manual operation of the control lever of the boom-telescoping manual operating device.
[0039] The telescopic-boom-length detection means 36 detects an actual overall length of
the telescopic boom 10 shown in FIG. 1 (the overall length will hereinafter be called
simply "telescopic boom length"), specifically, to input a telescopic-boom-length
detection signal 36a corresponding to a detected telescopic boom length into the control
unit 40. The load detection means 37 detects a hoisting load applied to the boom point
of the telescopic boom 10 and inputs a load detection signal 37a corresponding to
a detected hoisting load into the control unit 40.
[0040] The moment limiting device 38, which is designed to limit a tipping moment of the
crane so as to prevent actual tipping, overloading or the like, sets an allowable
value of the hoisting load, based on values detected by the telescopic-boom-length
detection means 36, the load detection means 37, a boom-angle detector (not shown),
etc., respectively. The allowable value is set on an assumption that the actual extension
amounts of the respective boom members 12b to 12e of the movable boom member assembly
12 are equal to their respective regular extension amounts. The allowable value, however,
may be limited, when a given condition is satisfied, by the control unit 40 (see an
after-mentioned third embodiment).
[0041] When a value detected by the load detection means 37 is greater than the allowable
value, the moment limiting device 38 inputs a stop command signal 38a into the control
unit 40 to stop a hoisting operation. It is also possible that each of the telescopic-boom-length
detection means 36 and the load detection means 37 is connected to the control unit
40 via the moment limiting device 38.
[0042] The control unit 40 may control various other operations, in addition to the telescoping
operation of the telescopic boom 10, such as hoisting or lowering of the telescopic
boom 10, slewing of a slewing upper structure (not shown), and hoisting.
[0043] Next will be described a specific telescoping control operation to be performed by
the control unit 40 with reference to the flowcharts shown in FIGS. 3 and 4. The control
includes the following routines, which are repeated every a given short period of
time.
<Control Switching (Steps S1 to S3)>
[0044] The control switching section 45 of the control unit 40 detects a control selected
through the manual operation of the control selector switch 32 (Step S1), and fundamentally
switches an actual control subroutine to the selected control. Specifically, when
the "individual telescoping control" is selected (NO in the Step S1), the control
switching section 45 switches the control to be performed by the control unit 40 to
the individual telescoping control based on the individual telescoping control section
42 (Step S20). On the other hand, when the "automatic telescoping control" is selected
(YES in Step S1), the control switching section 45 switches the control to the automatic
telescoping control (Step S10) by the automatic telescoping control section 41 on
condition that an after-mentioned automatic-telescoping-control switching prohibition
flag F1 is OFF (YES in Step S2), while the control switching section 45 does not switch
to the automatic telescoping control irrespective of the selection by the control
selector switch 32 on condition that the flag F1 is ON (NO in the Step S2). The automatic-telescoping-control
switching prohibition flag F1 is selectively set to ON or OFF by the automatic-telescoping-control
switching prohibition section 43 and the switching-prohibition release section 44,
as described in detail later. Upon the finish of the performance of the individual
telescoping control, an automatic- telescoping-control flag F2 is set to OFF (Step
S21).
<Automatic Telescoping Control (Step S10)>
[0045] The automatic telescoping control section 41 performs an automatic telescoping control
for automatically imparting a telescopic motion to each of the movable boom members
(2nd to 5th boom members 12b to 12e) according to the regular boom-telescoping sequence.
The automatic telescoping control is used during a normal crane operation.
[0046] FIG. 4 shows a subroutine for the automatic telescoping control. Immediately after
switching from the individual telescoping control to the automatic telescoping control,
the automatic-telescoping-control flag F2 is OFF (Step S21 in FIG. 3 ; NO in Step
S11); therefore, after only determining a movable boom member to be moved (hereinafter
referred to as "target boom member") based on a current telescopic boom length (Step
S12), the control unit 40 changes the automatic-telescoping-control flag F2 to ON
(Step S13). In summary, the automatic-telescoping-control flag F2 is set to OFF (1)
in its initial state, (2) during the performance of the individual telescoping control
(Step S20) , and (3) immediately after switching from the individual telescoping control
to the automatic telescoping control, while it is set to ON upon the routine for the
automatic telescoping control (the Step S 10) shown in FIG. 4 has been performed continuously
two times or more (Step S13), and subsequently will be kept ON during the performance
of the automatic telescoping control.
[0047] In the Step 12, the automatic telescoping control section 41 determines a target
boom member to be telescopically moved from the movable boom member assembly 12, based
on the current telescopic boom length, i.e., based on the telescopic-boom-length detection
signal 36a. Specifically, it makes judgment on which condition of the following conditions
A to D the current telescopic boom length meets, and selects an n th boom member (where
n is an integer of 2 to 5; the same applies to the following description) corresponding
to the met condition, as a target boom member.
Condition A: (Telescopic boom length) < (2nd length + a) |
|
→ Select the 2nd boom member 12b |
Condition B: (2nd length + α) ≤ (Telescopic boom length) < (3rd length + a) |
|
→ Select the 3rd boom member 12c |
Condition C: (3rd length + a) ≤ (Telescopic boom length) < (4th length + a) |
|
→ Select the 4th boom member 12d |
Condition D: (4th length + α) ≤ (Telescopic boom length) |
|
→ Select the 5th boom member 12e |
[0048] Herein, the term "n th length" means an actual overall length of the telescopic boom
10 under a condition that, in FIG. 1, each of the n th boom member and any of the
movable boom members located on the side of the base end with respect to the n th
boom member is maximally extended, and any of the movable boom members located on
the side of the boom point with respect to the n th boom member is maximally retracted.
Besides, "a" is a constant (e.g., 0.5 m) for letting a parameter in each of the conditions
A to D correspond to the target boom member (the boom member to be selected).
[0049] The automatic telescoping control section 41, after setting the automatic-telescoping-control
flag F2 to ON (the Step S13), inputs a control signal for imparting a telescopic motion
to the selected target boom member into each valve of the hydraulic circuit 20 (Step
S 17). Subsequently, performed is a process of judgment on switching the target boom
member (Steps S 14 to S16).
[0050] This judgment is based on the permission signal 33a of the telescoping-target switching
permission switch 33. Specifically, when the permission signal 33a is OFF (NO in Step
S14), the selection of the currently target boom member is continued, regardless of
the actual telescopic boom length (Step S16). For example, during the extension operation
of the telescopic boom 10, even if the 2nd boom member 12b is selected as the target
boom member and the extension operation of the 2nd boom member 12b has been completed,
an extension operation of the 3rd boom member 12c is not started during the period
in which the permission signal 33a is OFF.
[0051] When the telescoping-target switching permission switch 33 is operated to change
the permission signal 33a from OFF to ON (YES in the Step S14), the next target boom
member is allowed to be determined based on the current telescopic boom length (Step
S15). In other words, upon the finish of the extension or retraction of the currently
selected target member, the movable boom member to be selected as the target boom
member is automatically switched to the next movable boom member.
[0052] In this way, the automatic telescoping control section 41 in this embodiment switches
the target boom member to a next movable boom member only after the manual operation
of the telescoping-target switching permission switch 33 (the rise of the permission
signal 33a), thus allowing the semi-automatic control, which complies with the regular
boom-telescoping sequence while taking the operator's intention into consideration,
to be achieved.
[0053] Furthermore, the telescoping-target switching permission switch 33, provided on the
control lever of the boom-telescoping manual operating device 31 as mentioned above,
allows an operator to manually operate both of the telescoping-target switching permission
switch 33 and the control lever at the same time, which prevents the efficiency of
the operation by the operator from being lowered and inhibits the burden on the operator
from being increased.
[0054] In this embodiment, the determination of the target boom member in the Step S15 is
performed by the judgment on which condition of the following conditions A to G a
current telescopic boom length meets. Specifically, the judgment on whether the current
telescopic boom length meets each of the conditions A to G is sequentially carried
out in this order, and the movable boom member (n th boom member) corresponding to
the met condition is selected as the target boom member.
Condition A: (Telescopic boom length) < (2nd length - a) |
|
→ Select the 2nd boom member 12b |
Condition B: (2nd length - a) ≤ (Telescopic boom length) < (2nd length + a) |
|
→ Switch between the 2nd and 3rd boom members 12b and 12c |
Condition C: (2nd length + α) ≤ (Telescopic boom length) < (3rd length - a) |
|
→ Select the 3rd boom member 12c |
Condition D: (3rd length - α) ≤ (Telescopic boom length) < (3rd length + a) |
|
→ Switch between the 3rd and 4th boom members 12c and 12d |
Condition E: (3rd length + a) ≤ (Telescopic boom length) < (4th length - a) |
|
→ Select the 4th boom member 12d |
Condition F: (4th length - a) ≤ (Telescopic boom length) < (4th length + a) |
→ Switch between the 4th and the 5th boom member 12d and 12e |
Condition G: (4th length + a) ≤ (Telescopic boom length) |
|
→ Select the 5th boom member 12e |
[0055] When either of the conditions B, D, F is met, the target boom member is switched
to the distal end-side one of the two movable boom members during the extension operation,
whereas the target boom member is switched to a base-end-side one (a boom-foot-side
one) of the two movable boom members during the extraction operation. For example,
in the case where the condition B is met during the extension operation, the target
boom member is switched from the 2nd boom member 12b to the 3rd boom member 12c; in
the case where the condition B is met during the retraction operation, the target
boom member is switched from the 3rd boom member 12c to the 2nd boom member 12b. In
the above conditions, "a" is a constant (e.g., 0.5 m) for letting a parameter in each
of the conditions A to D correspond to the target boom member (boom member to be selected).
[0056] The automatic telescoping control section 41 inputs the control signals 21 s, 22s,
26s and 28s (FIG. 2) for moving the thus determined target boom member into each of
the valves 21, 22, 26 and 28 in the hydraulic circuit 20 (the Step S17).
<Individual Telescoping Control (Step S20)>
[0057] The individual telescoping control section 42 performs an individual telescoping
control for making only a manually selected one of the movable boom members be moved
individually in the telescoping direction of the telescopic boom. This individual
telescoping control is used, for example, during maintenance (or repair, inspection,
etc.) of the telescopic boom 10.
[0058] The individual telescoping control is not only performed in a first case that the
individual telescoping control is selected by the control selector switch 32 but also
continued in a second case that the automatic telescoping control is selected while
the automatic-telescoping-control switching prohibition section 43 prohibits switching
from the individual telescoping control to the automatic telescoping control. Specifically,
the individual telescoping control section 42, in the first case, selects a movable
boom member (one of the n th boom members 12b to 12e) which is manually selected by
an operator using the control selector switch 32, i.e., which is specified by the
individual-telescoping-control selection signal 32b, as the target boom member, and
then inputs the control signals 21 s, 22s, 26s and 28s into the valves 21, 22, 26
and 28 of the hydraulic circuit 20 respectively to make the selected target boom member
be moved. In the second case where, in spite of the selection of the automatic telescoping
control by the control selector switch 32, the individual telescoping control is continued
due to the automatic-telescoping-control switching prohibition flag F1 of ON, the
individual telescoping control section 42 does not output the control signals, that
is, keep the telescopic boom 10 in a current state.
[0059] On the other hand, upon the finish of the performance of the individual telescoping
control, the automatic- telescoping-control flag F2 is set to OFF (Step S21).
< Prohibition against Switching to Automatic Telescoping Control (Steps S31 and S32)>
[0060] The automatic-telescoping-control switching prohibition section 43, when the telescoping
operation of the telescopic boom 10 fulfils a specific condition (Step S31), sets
the automatic-telescoping-control switching prohibition flag F1, which is one for
switching the control selected by the control selector switch 32 from the individual
telescoping control to the automatic telescoping control, to ON (Step S32).
[0061] Specifically, in the Step S31, a judgment is performed on whether the movable booms
of the movable boom assembly 12 are operated in a sequence different from the regular
boom-telescoping sequence or not. If operated in a sequence different from the regular
boom-telescoping sequence (YES in the Step S31), the automatic-telescoping-control
switching prohibition flag F1 is set to ON (the Step S32). This produces a prohibition
against switching to the automatic telescoping control. If operated in the regular
boom-telescoping sequence (NO in the Step S31), the current automatic-telescoping-
control switching prohibition flag F1 is maintained.
[0062] According to the first embodiment, whether the sequence of the operations of the
respective movable boom members conforms to the regular boom-telescoping sequence
is judged based on the reference of the telescopic boom length and the target boom
member manually selected by the control selector switch 32. Specifically, if the target
boom member to be selected in the Step S12 (see FIG. 4) of the automatic telescoping
control is different from the actually manually selected target boom member, the telescopic
boom is judged as being in an irregularly selected state (YES in the Step S31). The
control unit 40 according to the first embodiment further comprises a operation limitation
section operative to fundamentally input the stop command signal 38a into the moment
limiting device 38 to automatically stop the telescoping operation of the telescopic
boom 10, in the case of the judgment of the telescopic boom as being in an irregularly
selected state, in addition to the prohibition against switching to the automatic
telescoping control switching prohibition. However, upon switching operation of an
automatic stop release switch (not shown) provided in the moment limiting device 38
to a "release" position, the telescoping operation of the movable boom members comprised
in the movable boom member assembly 12 is permitted in spite of the irregularly selected
state.
< Release of Prohibition against Switching to Automatic Telescoping Control (Steps
S41 and S42)>
[0063] The switching-prohibition release section 44, when the telescoping state of the telescopic
boom 10 satisfies a specific condition (YES in Step S41), releases the prohibition
against switching to the automatic telescoping control (Step S42). Specifically, the
switching-prohibition release section 44, in the Step S41, makes a judgment on whether
the state of the telescopic boom 10 satisfies a prohibition release condition that
the telescopic boom 10 is brought into a maximally shorten state where the telescopic
boom length is equal to a basic length, or into a maximally extended state (longest
state), by the individual telescoping control. The switching-prohibition release section
44, only in the case that the prohibition release condition is satisfied (YES in the
Step S41), set the automatic-telescoping-control switching prohibition flag F1 to
OFF (the Step S42), whereas, in the case of not satisfied (NO in the Step S41), it
maintains the automatic-telescoping-control switching prohibition flag F1 in a current
state. As described above, the control unit 40 according to the first embodiment has
a feature of comprising the automatic-telescoping-control switching prohibition section
43, and the switching-prohibition release section 44, as shown in FIG. 3. The automatic-telescoping-control
switching prohibition section 43 makes a prohibition against switching from the individual
telescoping control to the automatic telescoping control in the case that the movable
boom members are telescopically moved in a sequence different from the regular boom-telescoping
sequence during the individual telescoping control (the Step S32), because, in this
case, the telescopic boom 10 can be placed in an irregular telescope state where the
movable boom members have respective actual extension amounts different from their
respective regular extension amounts. Furthermore, the switching-prohibition release
section 44, when the telescopic boom 10 has been brought into the maximally retracted
or maximally extended state by the manual operation in the individual telescoping
control, releases the prohibition against switching to the automatic telescoping control
(the Step S42), because the maximal extension or retraction of the telescopic boom
10 always makes an actual extension amount of each of the movable boom members be
equal to the regular extension amount.
[0064] The above prohibition against switching to the automatic telescoping control is effective
in enhancing safety in a crane operation. Since operators, in general, select the
automatic telescoping control for performing a crane operation so as to rely on a
machine, the prohibition against switching to the automatic telescoping control can
allow the operators to know that the telescopic boom 10 is in the irregular telescope
state where the actual extension amounts of the movable boom members are different
from their respective regular extension amounts, thereby inhibiting the operators
from wrongly performing a crane operation based on the automatic telescoping control
in the irregular telescope state.
[0065] Next will be described a second embodiment according to the present invention with
reference to the flowchart shown in FIG. 5 corresponding to the flowchart in FIG.
3. The second embodiment is the same as the first embodiment except a difference in
the following points a to c.
- a. The control unit further comprises an extension-amount storage section 46 operative
to store respective actual extension amounts of the movable boom members of the movable
boom member assembly 12 shown in FIG. 1 (Step S25).
- b. The control unit further comprises an extension-amount correction section 47 operative
to correct the stored actual extension amounts (Steps S71 and S72).
- c. The switching-prohibition release section 44 has a function of removing, when the
telescoped state of the telescopic boom 10 is different from the irregular telescope
state (YES in Step 43), the prohibition against switching to the automatic telescoping
control (Step S42).
[0066] The extension-amount storage section 46 stores therein respective actual extension
amounts of the movable boom members, i.e., the 2nd to 5th boom members 12b to 12e.
Each of the actual extension amounts is calculated based on a change in the telescopic
boom length (based on change in the telescopic-boom-length detection signal 36a) and
the selection of the target boom member. The storage of the actual extension amounts
is performed even during the performance of the automatic telescoping control which
cannot cause the irregular telescope state. During the performance of the automatic
telescoping control, the actual extension amount can be calculated also by subtracting
a sum of respective lengths of the movable boom members on the side of the boom foot
with respect to the target boom member from an actual overall length of the telescopic
boom 10.
[0067] Following the storage of the actual extension amounts, the extension-amount correction
section 47, if the telescopic boom 10 is in the maximally retracted or extended state
(YES in the Step S71), corrects the actual extension amounts stored in the extension-amount
storage section 46 (the Step S72). Specifically, the extension-amount correction section
47 corrects the actual extension amounts of the movable boom members to 100% of their
respective length when the telescopic boom 10 is maximally extended, while it corrects
the actual extension amounts of the movable boom members to 0% of their respective
length when the telescopic boom 10 is maximally retracted.
[0068] Following the correction, the switching-prohibition release section 44 makes a judgment
on whether the telescopic boom 10 is in the irregular telescope state (the Step S43),
that is, a judgment whether there is a difference between an actual extension amount
of at least one of the movable boom members stored in the extension-amount storage
section 46 and the regular extension amount corresponding to the stored extension
amount. More specifically, the switching-prohibition release section 44 checks each
of the extension amounts of the movable boom members stored in the extension-amount
storage section 46, in order from one thereof closest to the boom foot to one thereof
closest to the boom point, and determines that the telescopic boom is in the irregular
telescope state, if a boom member having an actual extension amount greater than a
given value (e.g., 0.5 m) exists on the side of the boom point with respect to a boom
member having an actual extension amount of less than the 100% length (± a (e.g.,
a = 0.5 m)).
[0069] When it is determined that the telescopic boom is not in the irregular telescope
state (YES in the Step S43), the switching-prohibition release section 44 sets the
automatic-telescoping- control switching prohibition flag F1 to OFF to release the
prohibition against switching to the automatic telescoping control. If the automatic-telescoping-control
switching prohibition flag F1 has been already set to OFF, this is maintained. Meanwhile,
the irregular telescope state is ascertained (NO in the Step S43), the switching-prohibition
release section 44 keeps the automatic-telescoping-control switching prohibition flag
F1 in the current state.
[0070] The switching-prohibition release section 44 of the control unit 40 according to
the second embodiment releases the prohibition against switching to the automatic
telescoping control (the Step S42) on a condition that the actual extension amounts
of all of the movable members are equal to their respective regular extension amounts
(the Step S43) even if the telescopic boom 10 is not maximally retracted or extended.
This enables the prohibition to be adequately released more in a shorter period of
time, as compared with the cases where the prohibition against switching to the automatic
telescoping control is released only on the condition that the telescopic boom 10
is placed in the maximally retracted or extended state.
[0071] There will be described a third embodiment of the present invention with reference
to FIG. 6 corresponding to the flowchart in FIG. 3. The third embodiment is the same
as the second embodiment except that the third embodiment further includes a crane-capacity
limiting section 48 to limit a crane capacity when the telescopic boom is in the irregular
telescope state (NO in Step S43).
[0072] Specifically, the crane-capacity limiting section 48 is operative to make the moment
limiting device 38 set the allowable value of the hoisting load to a lower value when
the switching-prohibition release section 44 ascertains the irregular telescope state
(NO in the Step S43) than a value when the switching to the automatic telescoping
control is permitted, i.e., when the telescopic boom is not in the irregular telescope
state. In the third embodiment, the crane-capacity limiting section 48 is configured
to input an allowable-value limiting command signal 38b (FIG. 2) for limiting the
allowable value to a given value or less into the moment limiting device 38 (Step
S81), thereby limiting the crane capacity as compared with a normal state. The allowable
value of the hoisting load may be limited to 0 (zero) t, which results in a full prohibition
of a crane operation of hoisting a load while permitting only a movement of the telescopic
boom 10. Alternatively, the allowable value of the hoisting load may be set to a give
value (> 0) enough to reliably avoid damage of the telescopic boom 10. On the other
hand, when the telescopic boom is not in the irregular telescope state (YES in the
Step S43), the crane-capacity limiting section 48 returns the allowable value of the
hoisting load to be set by the moment limiting device 38 to a normal value (Step S82).
[0073] In the control unit according to the third embodiment, the crane-capacity limiting
section 48 limits the crane capacity when the prohibition against switching to the
automatic telescoping control is performed, i.e., the telescopic boom is in the irregular
telescope state where an actual extension amount of at least one of the movable boom
members is not equal to its regular extension amount, to thus preventing an operator
from performing a crane operation of hoisting a load in the irregular telescope state
without noticing, thereby further enhancing the safety of the crane operation.
[0074] As shown in the flowcharts of FIGS. 7 and 8, which correspond to FIGS. 3 and 4 respectively
and discloses an embodiment not included in the present invention, only the crane
capacity may be limited without inhibiting the switching to the automatic telescoping
control. In FIG. 7, when the automatic telescoping control is selected by the control
selector switch 32 (YES in Step S1), the boom telescoping control routine is unconditionally
switched to an automatic telescoping control subroutine (Step S410), and the automatic-telescoping-control
flag F2 is set to ON (Step S44) when the telescopic boom is not in the irregular telescope
state (YES in Step S43).
[0075] On the other hand, in the automatic telescoping control (the Step S410), the target
boom member is determined, irrespective of the telescopic boom length (Steps S418,
S419a and S419b), as shown in FIG. 8, when the telescopic boom is in the irregular
telescope state (NO in Step S 11); , the target boom member is set based on the telescopic
boom length (Steps S 14 to S16) when the telescopic boom is not in the irregular telescope
state (YES in Step S 11), the target boom member is set based on the telescopic boom
length (Steps S 14 to S16).
[0076] In the Steps 418, there is made a judgment on whether the telescoping operation is
an extension operation or a retraction operation. In the case of not extension operation
(NO in the Step S418), the target boom member is selected from the movable boom members
in order from one thereof closest to the boom point, irrespective of the telescopic
boom length. Then, following the finish of the retraction operation of the selected
target boom member, an adjacent one of the movable boom members on the side of boom
foot is newly selected as a next target boom member. More specifically, for example
in FIG. 1, the 5th boom member 12e as a movable boom member closest to the boom point
is firstly retracted. Then, following the finish of the retraction operation of the
5th boom member 12e (for example, after a given time from the time at which a change
in the telescopic boom length has been stopped), an retraction operation of the adjacent
4th boom member 12d is started. Switching will be thus sequentially performed in the
order from the boom point to the boom foot.
[0077] On the other hand, in the case of the extension operation of the telescopic boom
10 (YES in the Step S418), the target boom member is selected from the movable boom
members in order from one thereof closest to the boom foot (from the 2nd boom member
12b, regardless of a length of the telescopic boom 10 (see FIG. 1). Then, following
the finish of the extension operation of the selected target boom member, an adjacent
(boom-point-side) one of the movable boom members is selected as a next target boom
member. In other words, performed is an operation reverse to the Step S419a.
[0078] The present invention is not limited to the above embodiments. For example, the control
unit 40 may additionally have a function of controlling an indicator adapted to indicate
an occurrence of the irregular telescope state where an actual extension amount of
each of the movable boom members is not equal to a regular extension amount thereof,
and/or a settlement of the irregular telescope state, within a crane cab. The indication
lets an operator know the present or absence of the irregular telescope state, thereby
more effectively preventing a normal crane operation from being continuously performed
in the irregular telescope state.
[0079] The number of boom members of the telescopic boom 10 shown in FIG. 1 can be changed.
Means for driving the movable boom members is not limited to the telescopic cylinder;
for example, in place of or in addition to the telescopic cylinder, there may be employed
a wire rope for telescopically driving the movable boom members. For example, there
may be a 6th boom member and a 7th boom member to be attached to the side of a distal
end of the 5th boom member 12e so as to be telescopically and simultaneously driven
by the wire rope. In this case, the above telescoping control may be performed for
the 2nd to 5th boom members 12b to 12e.
[0080] Provided is a boom telescoping control unit (40) for controlling a telescoping operation
of a telescopic boom (10) having a plurality of movable boom members (12b to 12e).
The boom telescoping control unit (40) comprises automatic telescoping control means
(41) to perform an automatic telescoping control for sequentially moving the movable
boom members (12b to 12e) according to a regular boom-telescoping sequence; individual
telescoping control means (42) to perform an individual telescoping control for moving
only a manually selected one of the movable boom members individually; control switching
means (45) including a selector switch_(32) for selecting between the automatic telescoping
control and the individual telescoping control, wherein the control switching means
switches, based on the selection by the selector switch, between the two telescoping
controls; automatic-telescoping-control switching prohibition means (43) operative
to make a prohibition against switching from the individual telescoping control to
the automatic telescoping control, irrespective of the selection by the selector switch
(32), under a condition that, when the telescopic control selected by the selector
switch (32) is switched from the individual telescoping control to the automatic telescoping
control, the movable boom members (12b to 12e) have been moved in a sequence different
from the regular boom-telescoping sequence; and switching-prohibition release means
(44) to release the prohibition when the entire telescopic boom (10) has been brought
into a maximally retracted or extended state.
1. Auslegerteleskopiersteuereinheit (40) zum Steuern einer Teleskopierbewegung eines
Teleskopauslegers (10), der eine Vielzahl von bewegbaren Auslegerelementen (12b bis
12e) hat, die in der Lage sind, relativ zueinander verschoben zu werden, um den gesamten
Teleskopausleger teleskopisch zu bewegen, wobei die Auslegerteleskopiersteuereinheit
(40) Folgendes aufweist:
ein Automatikteleskopiersteuermittel (41), das dazu betriebsfähig ist, ein Zielauslegerelement
zu bestimmen, das von den bewegbaren Auslegerelementen (12b bis 12e) sequenziell teleskopisch
zu bewegen ist, und nur das ausgewählte, bewegbare Element als das Zielelement so
bewegen zu lassen, um die bewegbaren Auslegerelemente (12b bis 12e) in einer Teleskopierrichtung
des Teleskopauslegers (10) gemäß einer vorbestimmten, regulären Auslegerteleskopiersequenz
sequenziell bewegen zu lassen, um den Teleskopausleger (10) automatisch teleskopisch
zu bewegen;
ein Individualteleskopiersteuermittel (42), das dazu betriebsfähig ist, lediglich
ein manuell ausgewähltes der bewegbaren Auslegerelemente (12b bis 12e) individuell
in der Teleskopierrichtung des Teleskopauslegers (10) bewegen zu lassen;
ein Steuerschaltmittel (32, 45), das einen Wählschalter (32) zum Auswählen zwischen
einer durch das Automatikteleskopiersteuermittel (41) durchgeführten Automatikteleskopiersteuerung
und einer durch das Individualteleskopiersteuermittel (42) durchgeführten Individualteleskopiersteuerung
aufweist, wobei das Steuerschaltmittel (32, 45) dazu betriebsfähig ist, auf Grundlage
der Auswahl durch den Wählschalter (32) zwischen der Automatikteleskopiersteuerung
und der Individualteleskopiersteuerung umzuschalten;
ein Automatikteleskopiersteuerungschaltverhinderungsmittel (43), das dazu betriebsfähig
sind, ein Verbot gegen das Umschalten von der Individualteleskopiersteuerung auf die
Automatikteleskopiersteuerung ungeachtet der Auswahl durch den Wählschalter (32) unter
der Bedingung zu erlassen, dass die bewegbaren Auslegerelemente (12b bis 12e) in einer
Sequenz bewegt wurden, die sich von der regulären Auslegerteleskopiersequenz unterscheidet,
wenn die durch den Wählschalter (32) ausgewählte Teleskopiersteuerung von der Individualteleskopiersteuerung
auf die Automatikteleskopiersteuerung umgeschaltet wird; und
ein Schaltverbotaufhebungsmittel (44), das dazu betriebsfähig ist, das Verbot durch
das Steuerschaltverbotmittel (43) aufzuheben, wenn der gesamte Teleskopausleger (10)
in einen maximal eingefahrenen Zustand oder einen maximal ausgefahrenen Zustand gebracht
wurde.
2. Auslegerteleskopiersteuereinheit (40) gemäß Anspruch 1, wobei die reguläre Auslegerteleskopiersequenz
eine Sequenz ist, in der die bewegbaren Auslegerelemente (12b bis 12e) in einer Ausfahrrichtung
in der Reihenfolge von dem bewegbaren Auslegerelement am nahesten zu einem Basisende
des Teleskopauslegers zu dem bewegbaren Auslegerelement am nahesten zu einem distalen
Ende des Teleskopauslegers bewegt werden, um den Teleskopausleger (10) auszufahren,
während die bewegbaren Auslegerelemente (12b bis 12e) in einer Einfahrrichtung in
der Reihenfolge von dem bewegbaren Auslegerelement am nahesten zu dem distalen Ende
zu dem bewegbaren Auslegerelement am nahesten zu dem Basisende bewegt werden, um den
Teleskopauslegers (10) einzufahren.
3. Auslegerteleskopiersteuereinheit (40) gemäß Anspruch 1 oder 2, der ferner ein Ausfahrbetragspeichermittel
(46) aufweist, das dazu betriebsfähig ist, in sich jeweilige gegenwärtige Ausfahrbeträge
der bewegbaren Auslegerelemente (12b bis 12e) zu speichern, wobei das Schaltverbotaufhebungsmittel
(44) dazu betriebsfähig ist, das Verbot unter der Bedingung aufzuheben, dass die in
dem Ausfahrbetragspeichermittel (46) gespeicherten gegenwärtigen Ausfahrbeträge gleich
wie ihre jeweiligen regulären Ausfahrbeträge werden, die angenommene Ausfahrbeträge
der jeweiligen bewegbaren Auslegerelemente (12b bis 12e) sind, wenn die bewegbaren
Auslegerelemente (12b bis 12e) in der regulären Auslegerteleskopiersequenz teleskopisch
bewegt wurden.
4. Auslegerteleskopiersteuereinheit (40) gemäß einem der Ansprüche 1 bis 3, der dazu
ausgelegt ist, in einem Kran verwendet zu werden, der eine Momentbegrenzungsvorrichtung
(38) aufweist, um einen zulässigen Wert einer Hublast des Teleskopauslegers (10) festzulegen,
um ein durch ein Eigengewicht des Teleskopauslegers (10) und die Hublast erzeugtes
Kippmoment zu begrenzen, wobei die Auslegerteleskopiersteuereinheit (40) ferner ein
Krankapazitätsbegrenzungsmittel (48) aufweist, das dazu betriebsfähig ist, die Momentbegrenzungsvorrichtung
(38) den zulässigen Wert der Hublast auf ein Niveau festzulegen, wenn das Verbot gegen
das Umschalten auf die Automatikteleskopiersteuerung durch das Automatikteleskopiersteuerschaltverbotmittel
(43) erlassen wird, das niedriger als ein Niveau der Hublast ist, wenn das Verbot
nicht erlassen wird.
5. Kran, der mit einem Teleskopausleger (10) ausgestattet ist und Folgendes aufweist:
einen Hydraulikkreislauf (20) zum Antreiben des Teleskopauslegers (10);
eine Momentbeschränkungsvorrichtung (38), die dazu angepasst ist, einen zulässigen
Wert einer Hublast für den Teleskopausleger (10) so festzulegen, dass ein durch ein
Eigengewicht des Teleskopauslegers (10) und die Hublast erzeugtes Kippmoment begrenzt
wird; und
eine Auslegerteleskopiersteuereinrichtung, die dazu angepasst ist, ein Steuersignal
in den Hydraulikkreislauf (20) einzugeben, wobei die Auslegerteleskopiersteuereinheit
aus der in Anspruch 4 definierten Auslegerteleskopiersteuereinheit (40) ausgebildet
ist,
und wobei das Krankapazitätsbeschränkungsmittel (48) der Auslegerteleskopiersteuereinheit
(40) dazu betriebsfähig ist, die Momentbeschränkungsvorrichtung (38) den zulässigen
Wert der Hublast auf ein Niveau festzulegen, wenn das Verbot gegen das Umschalten
auf die Automatikteleskopiersteuerung durch das Automatikteleskopiersteuerschaltverbotmittel
(43) erlassen wird, das niedriger als ein Niveau ist, wenn das Verbot nicht erlassen
wird.