Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a machine comprising a
machine frame movable along a track on undercarriages
supporting the machine frame on the track, the machine frame
carrying a rotary crane comprising an extensible boom and ; ;~
drives for operating the crane.
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2. Description of the Prior Art
U. S. patent No. 4,399,881 discloses such a track-bound
rotary crane, which includes an arrangement for continuously
monitoring and indicating the loads on the respective wheels -~-
of the undercarriages. In addition, a hydraulic cylinder is ~ - -
arranged between the machine frame and each undercarriage for ~ --
equalizing the loads on the wheels. In this system, it is
possible to take the additional load produced by a rotation of
the crane into account in the calculation of the wheel loads,
for which purpose an electrical pressure pickup is associated
with each hydraulic cylinder. ` ;
U. S. patent No. 4,113,111 also discloses such a vehicle `
equipped with an arrangement for equalizing the wheel loads, - -`
which is comprised of shock-absorbing pressure cylinders
mounted between the undercarriages and the machine frame. The
upper and lower cylinder chambers of the shock absorbers at
one side of the vehicle are interconnected by conduits which
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may be blocked. In this way, a desired torsion may be
imparted to the machine frame so that the more heavily loaded -
wheels may be relieved and the less heavily loaded wheels may
be subjected to an additional load.
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SUMMARY OF THE INVENTION
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It is the primary object of this invention to provide a
track-bound rotary crane of the first-indicated type, which
attains the highest attainable safety in each operating - -
position of the crane while at the same time achieving its ;
maximal operating capacity.
In a machine comprising a machine frame movable along a
track on undercarriages supporting the machine frame on the
track, the machine frame having vertically adjustable support
jacks and drives for vertically adjusting the support jacks
between a retracted position during movement of the machine
frame along the track and an extended operating position for `
support of the machine frame on the track, and the machine
frame carrying a rotary crane comprising an extensible boom,
the above and other objects are accomplished according to the
invention with a rotary crane comprising a hydraulic cylinder
drive for vertically adjusting the extensible crane boom, the ~ b
hydraulic cylinder drive including a signal transmitter
indicating the hydraulic pressure in the cylinder drive, a
drive for changing the length of the extensible boom, and a
further drive for rotating the rotary crane on the machine
frame about a substantially vertical axis whereby the crane
boom may assume different angles of rotation with respect to a
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longitudinal direction of the machine frame. The rotary crane
further comprises a control associated with the nydraulic
cylinder drive for vertically adjusting the extensible crane
boom, the drive for changing the extensible boom length and
the further drive for rotating the rotary crane. The control
is connected to the signal transmitter indicating the
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hydraulic pressure in the cylinder drive and to at least one
measuring device selected from the group consisting of a
signal transmitter indicating the superelevation of the track,
a signal transmitter indicating the angle of rotation of the
rotary crane, a signal transmitter indicating changes in the
extensible boom length, and a signal transmitter indicating
the position of the support jacks, whereby a reference value
signal corresponding to a maximum permissible load for the ;-~ -
crane in a given operating position is generated, and the -
control comprises a differential comparator unit for comparing
the reference value signal with an output signal of the signal
transmitter indicating the hydraulic pressure in the cylinder
drive. An overload device is connected to the control for
controlling the drives when the differential comparator unit
indicates an overload. `~
Such a machine makes it possible to use without any
problems the maximal load moment in every operating position
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of the rotary crane without endangering the stability of the~ -
machine. This enables the track-bound rotary crane to be used
efficiently at its highest capacity. The differential ~
comparator unit in the control assures a continuous and -~ -
constant comparison between a reference value signal which -
depends on the operating position of the crane and corresponds
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to the maximum load which the crane may carry, and the actual
value signal emitted by the signal transmitter indicating the
hydraulic pressure in the vertical adjustment hydraulic
cylinder drive. The different signal transmitters monitoring
practically all operating positions of the crane make it
possible to take into account just about every crane position
By including such parameters as the track superelevation, for
example, the load moment for the crane may be increased up to
15% at a maximum superelevation where the crane has been
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rotated toward the higher side of the superelevated track. On
the other hand, when the rotary crane is turned to the
opposite, lower track side, a corresponding reduction of the ~ ~`
maximal load and its corresponding reference value signal is
automatically achieved so that the crane may be used in track `
curves with optimal efficiency and safety. The system
excludes operating mistakes due to human error.
According to a preferred feature of the present - ;~
invention, the crane boom comprises a first arm pivotal about
a horizontal axis extending transversely to the machine frame
and a second arm slidably displaceable with respect to the -~
first arm for changing the length of the extensible crane
boom, the drive for changing the length comprising a hydraulic
cylinder for displacing the second arm with respect to the
first arm, and the signal transmitter indicating changes in ~ -
the extensible boom length being a cable potentiometer. This
arrangement provides a very simple and dependable structure
for monitoring the length of the crane boom for determining
the maximum load moment for a given crane boom length.
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The pivoting angle of the crane boom arms may be
monitored ready with an arrangement wherein the crane boom
further comprises a support arm, the hydraulic cylinder drive
for vertically adjusting the extensible crane boom being
connected to the support arm and the first arm being linked to ~;
the support arm for pivoting about the horizontal axis,
further comprising a hydraulic cylinder drive linking the
first arm to the support arm for pivoting the first arm, and a ~ -
measuring device for indicating the angle between the support
and first arms. This enables an increase in the maximally
permissible load moment due to a position of the crane boom
arms closer to the vertical than the horizontal to be taken
into account. The angle indicating measuring device may be a
cable potentiometer arranged to indicate changes in the length
of the hydraulic cylinder drive for pivoting the first arm or
a rotary potentiometer whose axis of rotation is coaxial with
the horizontal axis.
According to another preferred feature, the rotary crane
further comprises a support column mounted on the machine
frame for rotation about the vertical axis by the further ~ ~
drive, the support column carrying the support arm and the `~- `
hydraulic cylinder drive connected thereto, a counterweight
mounted on the support column for displacement in a horizontal
plane in a dir~ction extending perpendicularly to the
horizontal axis, and a drive for displacing the counterweight.
Such a structure provides a very efficient crane operating `-~
within the loading gage of the track.
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The signal transmitter indicating the superelevation of
the track may comprise a pendulum mounted on the machine frame
for pivoting about a horizontal axis extending in the
longitudinal direction, the pendulum carrying a damped :~-
pendulum weight, which has the advantage that the track
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superelevation may be dependably monitored even if the shut~
off device for the shock absorbers of the undercarriages does ~ ;~
not function properly.
Furthermore, the signal transmitter indicating the angle
of rotation of the rotary crane preferably has a positive and
a negative signal range respectively positioned at a left and -~
a right half of the machine frame on respective sides of a ~`
common zero position defined by a plane extending in the
longitudinal direction through the vertical axis. This makes
it possible accurately to determine the angular position of ~ -
the crane boom not only relative to the longitudinal direction
but also with respect to the left and right halves of the
machine frame.
Finally, the machine may further comprise an auxiliary
frame mounted on the machine frame for rotation about a
vertical axis over an angle of rotation of 180~, the rotary
crane being mounted on the auxiliary frame at one end thereof,
as seen in the longitudinal direction. This makes it possible
simply and rapidly to relocate the crane from one end of the
machine frame to the other by turning the auxiliary frame,
rather than having to turn around the entire machine, which
would be time-consuming and creates problems with the
stability of the machine.
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BRIEF DESCRIPTION OF THE DRAWING
The above and other objects, advantages and features of
the present invention will become more apparent from the ~--
following detailed description of a now preferred embodiment
thereof, taken in conjunction with the accompanying, somewhat
schematic drawing wherein
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FIG. 1 is a side elevational view showing a machine
according to this invention; and
FIG. 2 is a simplified circuit diagram of the control
circuit.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing and first to FIG. 1, there
is shown machine 1 comprising machine frame 2 movable along
track 40 on undercarriages 3 supporting the machine frame on
the track. Machine 1 may be used as a railway crane, as a
freight car for transporting materials and personnel, as well
as an auxiliary vehicle in track maintenance or rehabilitation
work. Undercarriages 3 are three-axle trucks. A rotary ~;~
support 6 mounts an auxiliary frame 5 on machine frame 2, and ;
drive 7 engages the rotary support for rotation of the
auxiliary frame about vertical axis 8 over an angle of
rotation of 180. A rotary crane 4 is mounted on auxiliary
frame 5 at one end thereof, as seen in the longitudinal
direction. A blocking device 9 is arranged at each end of
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auxiliary frame 5 to retain the auxiliary frame in its
respective end position in alignment with machine frame 2.
The machine frame has vertically adjustable support jacks 32
and hydraulic drives 33 for vertically adjusting the support
jacks between a retracted position during movement of the
machine frame along the track and an extended operating
position for support of the machine frame on the track.
Rotary crane 4 carried by machine frame 2 comprises
extensible boom 18 comprised of first arm 12 and second arm
13, the first arm being linked to support arm 11 for pivoting
about horizontal axis 16 extending transversely to the machine
frame and second arm 13 being slidably displaceable with
respect to first arm 12 for changing the length of the
extensible crane boom. A hydraulic cylinder drive 14 for
vertically adjusting the extensible crane boom is connected to ~ ~:
support arm 11 and a hydraulic cylinder drive 15 links first
arm 12 to support arm 11 for pivoting the first arm.
Hydraulic cylinder drive 14 includes signal transmitter 25
indicating the hydraulic pressure in the cylinder drive. -
Hydraulic drive 17 connects second arm 13 to first arm 12 for
slidably displacing the second arm to change the length of the
extensible boom. Further drive 19 is arranged to rotate
rotary crane 4 on machine frame 2 about substantially vertical
axis 20 whereby the crane boom may assume different angles of
rotation with respect to a longitudinal direction of machine
frame 2. The illustrated rotary crane further comprises
support column 10 mounted on machine frame 2 for rotation ~;
about vertical axis 20 by further drive 19, the support column ``
carrying support arm 11 and hydraulic cylinder drive 14 being
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connected to support column 10. Support arm 11 is supported
on support column 10 for pivoting about horizontal axis 16'
extending parallel to axis 16 so that hydraulic cylinder drive
14 may lower and raise the crane boom. A counterweight 22 is -~
mounted on support column 10 for displacement in a horizontal
plane in a direction extending perpendicularly to horizontal
axis 16, and drive 21 is arranged to displace the
counterweight.
At the end opposite the end supporting rotary crane 4,
auxiliary frame 5 carries driver's cab 30, and the auxiliary
frame defines loading platform 31 beneath boom 18 of the
rotary crane. Spaced from each other in the longitudinal
direction, three support jacks 32 are mounted on machine frame
2 at each side thereof. The vertically adjustable support
jacks have shoes 34, and drives 33 are operable for vertical
adjustment of support jacks 32 between a retracted position
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during movement of the machine frame along track 40 and an
extended operating position for support of the machine frame
on the track when jack shoes 34 engage the ends of the track
ties and support machine frame 2 thereon. - -~
A motor 37 is connected to drives 38 for moving machine 1
along the track and to hydraulic system 39 connected to
operating drives 14, 15, 17 and 19 for rotary crane 4.
Undercarriageg 3 have conventional blocking devices to block
the springs arranged between the undercarriages and machine
frame 2 so that the machine frame is held rigidly during
operation of the crane.
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Control circuit 23 controls the operation of hydraulic
cylinder drive 14 for vertically adjusting the extensible
crane boom, drive 17 for changing the extensible boom length
and further drive 19 for rotating rotary crane 4. The control
is connected to signal transmitter 25 indicating the hydraulic
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pressure in cylinder drive 14, and is further connected to at
least one measuring device selected from the group consisting ~-
of signal transmitter 26 indicating the superelevation of the `
track, signal transmitter 27 indicating the angle of rotation
~ of the rotary crane, signal transmitter 28 indicating
changes in the extensible boom length, and signal transmitter
35 indicating the position of support jacks 32, whereby a
reference value signal corresponding to a maximum permissible
load for the crane in a given operating position is generated. `
Control circuit 23 comprises differential comparator unit 44
for comparing the reference value signal with an output signal ~ ;~
of signal transmitter 25 indicating the hydraulic pressure in
cylinder drive 14. Overload control device 24 is connected to
the differential comparator unit of control 23 for controlling
the drives when the comparison of the signals in differential ~`
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unit 44 indicates an overload.
The signal transmitter 28 indicating a change in the ~-
extensible boom length is illustrated as cable potentiometer -~
29, one end of the cable being connected to the cylinder of
drive 17 while its other end is connected to the piston rod of
the drive so that the cable measures the length of the piston
rod extending from the cylinder.
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A measuring device including signal transmitter 41 is ~ -
provided to indicate the angle between the support arm 11 and
first arm 12, and this measuring device may be a cable
potentiometer arranged to indicate changes in the length of
hydraulic cylinder drive 15 for pivoting the first arm, -~-
similar to the cable potentiometer described hereinabove in -~--
connection with measuring device 28, or a rotary potentiometer
whose axis of rotation is coaxial with horizontal axis 16.
As shown in FIG. 2, signal transmitters 25, 26, 27, 28,
35 and 41 of the respective measuring devices are connected to
differential comparator unit 44 through signal amplifiers 42 ;
and microprocessor 43 to transmit the output signals of the
signal transmitters to the input of the differential -
comparator unit 44 after the output signals have been
amplified and processed in the microprocessor so that the sum
of the output signals of signal transmitters 26, 27, 28, 35
and 41 forms a reference value signal corresponding to a
maximum permissible load for the crane in a given operating
position. This reference value signal is fed to differential
unit comparator 44 in which it is compared with the actual
value signal transmitted by signal transmitter 25 indicating
the hydraulic pressure in cylinder drive 14. Overload control
device 24 is connected to the differential comparator unit of
control circuit 23 for controlling the drives when the
differential comparator unit emits an output signal indicating
an overload. The overload control device includes servo
valves 45 in the lines of hydraulic system 39 leading to -~
respective drives. The hydraulic lines from servo valves 45
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to vertical adjustment drive 14 and to drive 15 are shown in
FIG. 2. -~
Signal transmitter 26 indicating the superelevation of
track 40 comprises a pendulum mounted on machine frame 2 for
pivoting about a horizontal axis extending in the longitudinal
direction, the pendulum carrying a damped pendulum weight.
Signal transmitter 27 indicating the angle of rotation ~ of
rotary crane 4 has a positive and a negative signal range
respectively positioned at a left half 46 and a right half 47
of machine frame 2 on respective sides of a common zero
position defined by plane 36 extending in the longitudinal
direction through vertical axis 20. ; ~-
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Signal transmitters 35 may emit signals indicating the
hydraulic pressure in drives 33 for hydraulic jacks 32 to
indicate when the support jacks on at least one side of
machine frame 2 are in their extended operating position
wherein their shoes 34 rest on the tie ends to support at ~ ;
least one half of the machine frame on the tie ends, thus
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enhancing the stability of machine 1. In this operating
position, hydraulic system 39 operates automatically to supply
high hydraulic pressure to the operating drives of rotary
crane 4 whereby the crane is enabled to make full use of its
lifting capacity. When support jacks are retracted while
machine 1 is moved between operating sites or when crane 4 is
not used, as shown in FIG. 1, hydraulic system 39 operates
automatically at low pressure, at which the loading moment of
the crane is reduced. To assure a safe operation of rotary
crane 4 independent of the operating positions, shut-off
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device 24 in hydraulic system 39 is connected tomicroprocessor 43 and the signal transmitters 25, 26, 27, 28,
35 and 41 of the measuring devices. Signal transmitter 25 ~-~
transmits its output signal to microprocessor 43 and this
output signal indicates the prevailing value of the loading
moment to which crane 4 is subjected.
The reference value signal formed in microprocessor 43 is
the sum of the output signals received from signal ~ -~
transmitters 26, 27, 28, 35 and 41, which monitor and measure ;
the superelevation of the track, the rotary angle of the
crane, the length of the boom, position of the support jacks,
and the relative angular position of the first and support -
arms of the boom. In other words, this reference value signal
corresponds to the maximum permissible load depending on the
prevailing operating position of rotary crane 4.
The measuring device including signal transmitter 27 will
accurately monitor angle ~, which is the angle the crane boom ~
encloses with plane 36 at the right half or left half of ;~ ;
machine frame 2. If this angle is less than 20, the crane
can be subjected to its maximum load. If the angle exceeds
20-, microprocessor 43 will reduce the measuring signal by a ;~
predetermined amount, which depends on the structural details
of the crane, so that this signal corresponds to the maximum
load permissible at the monitored rotary angle of the crane.
'rhe measuring device including signal transmitter 26 will
accurately monitor the superelevation of track 40 to determine
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its output signal in track curves. If crane boom 18 is
positioned on the higher half of the machine frame in a curve, ~ -`
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the measuring signal is correspondingly amplified. In other
words, in this position of the boom, a higher load is
permissible. On the other hand, if the crane boom is
positioned on the lower machine frame half, the measuring
signal, i.e. the reference value signal, is reduced.
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Since the maximum load for the crane also depends on the
length of boom 18, the signal received from signal transmitter
28 is also a component of the reference value signal. Another
component is the signal from signal transmitter 41 because the
angle which crane boom 18 encloses with the horizontal also
influences the maximum load. -~
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The reference value signal derived from the sum of all `
these output signals in microprocessor 43 is compared in
differential comparator unit 44 with the actual value signal
emitted by signal transmitter 25 which monitors the prevailing ~;;
hydraulic pressure in hydraulic lifting cylinder 14, i.e. ;-~
indicates the actual value. If this actual value exceeds the
reference value, the output signal from the differential `~
comparator unit immediately actuates overload control device
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24, i.e. servo valves 45 are selectively operated so that
hydraulic drives 15, 17 and 19 may change the angle between
support arm 11 and first arm 12, the length of crane boom 18,
and the angle of rotation ~ of crane 4 so that the load moment
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is reduced. Furthermore, the load lifted by winch 48 on the
crane can only be lowered in this condition. When the
actual value is smaller than the reference value, overload
control device 24 is not activated and drives 14, 15, 17 and
19 continue to operate undisturbed.
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If desired, the distance of counterweight 22 from support
column 10 of rotary crane 4 may also be monitored by a further ~ -
measuring device including signal transmitter 49. This, too,
may be connected to control circuit 23 so that its output
signal forms à further component of the reference value
signal. It would also be possible to add another measuring ;
device monitoring a transverse displacement of support jacks ~ :~
32 which may be displaceable transversely to the longitudinal
direction by transverse displacement drives.
Since the maximum load for the crane in any given -
position of crane boom 18 is continuously monitored by the
various measuring devices and the reference value derived
therefrom is continuous compared with the actual value derived
from the crane lifting drive, the crane may be used at its
highest efficiency at all times. -~
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