Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR CHANGING. THE ~?ALLETS
OF A SINTE~i~ MA.CHINE
This in~ention relates to a method and an apparatus
for changing the pallets of a sinter machine when such
pallets are damaged~
Sinter machines of the endless type including a
train of pallets which move on upper rails from the
feed end to the discharge end of the machine are well
known. As they move along the upper rails, the pallets
pass over wind boxes for sintering the ~oncentrate loaded
on the pallets. The sintered concentrate is discharged
at the discharge end of the machine and the pallets
mOve back to the feed end of the machine along lower rails.
The pallets are transferred from the lower rails to the
upper rails ~y means of a lifting wheel located at the
feed end of the machine and are guided during such
transfer by guide rails following the arcuate path of
the lifting wheel.
The pallets are provided wi:th grate bars which
support the concentrate while allow~ng passage of hot
gases therethrough for sintering the concentrate. These
grate bars must ~e regularly replaced and this operation
requires removal of the pallets from the sinter machine.
The pallets are normally changed using overhead cranes
and tne whole operation is time consuming and hazardous
for the operators.
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It is therefore the. ohject o~ the presenk invention
to provide a novel method and apparatus for changing
pallets which is safer and less time consuming than the
conventional procedure.
The method, in accordance with the presenk
- inven~ion, comprises the steps of raising a used pallet
from the lifting wheel, placing a pair of tracks underneath
the wheels of the raised used pallet and depositing the
used pallet onto the tracks, lowering the end of the
tracks remote from the sinter machine to floor level and
discharging the used pallet from the tracks,raising the
same end of the tracks to the level of a stand facing the
feed end of the sinter machine and supporting a new pallet,
rolling the new pallet from such stand onto the
tracks, clamping the new pallet, moving the tracks out
of the way, and lowering the new pallet into the sinter
machine.
The.apparatu~ for carrying out the above method
comprises means for raising the used pallets from the
lifting wheel, a pair of tracks adapted to be positioned
underneath.the wheels of the raised used pallets for
depositing the used pallets thereon and rolling it out,
a stand facing the feed end of the sinter machine
for holding a new pallet, means for lowering the end of
the tracks remote from the sinter machine to floor level
to allow discharge of the used pallet from the ~racks
and for raising the erd of the tracks to the level of
the stand for rolling the new pallet from the stand
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onto the tracks to a cla~ping posi,tion, whe~eb~ the new
pallet may ~e ~nserted ~nto the sinte,~ machine,
The means for raising used pallets is preferably
a portion of the guide rails and include means fo~
pivotally mounting the upper end of each guide rail
portion, an hydraulic cylinder for pivoting the lower end
of such guide rail portion, and clamping means mounted on
such guide rail portion for clamping the used pallets.
An end stop is pre~erabl~ located at the end of
each track remo~e from the sinter machine for preventing
rolling out o~ the used pallets from the tracks during
lowering of such end portion of the tracks. ~ center
stop is preferably located on the floor for allowin~
release of the end stops and discharge of the used
pallets from the tracks.
The invention will be disclosed,b~ way of example,
with reference to a preferred embodiment illustrated in
the accompanying drawings in which:
Figure 1 ~llustrates a ~ront view o~ the pallet
changing apparatus in accqrdance with the invention;
Figures 2, 3, 6~ 8 and 11 illustrate diagrammetric
side views of the feed end of the sinter machine showing
the pallet changing apparatus during its various steps
of operation;
Figures 4 and 5 show end and side views of the end
stops of the pal~et changing apparatus~
Figure 7 shows a side view of the center stop of
the pallet changing apparatus; and
Figures 9 and 10 show end and side view of the
pallet contact stopper.
Referring to Figure 1 of the dra~ings, there is
shown an embodiment of the pallet changing apparatus
comprising a mechanism 10 located on each side of the
sinter machine for removing the pallets from the lifting
wheel 12 of the sinter machine. Also shown ls a track
14 located on each side of the sinter machine for
rolling out a used pallet and rolling in a new pallet.
There is further shown two stands 16 for supporting a
new pallet prior to insertion into the sinter machine
and two lower stands 17 for receiving an old pallet when
removed from the sinter machine. At the center of the
pallet changing apparatus is a center stop 18 which is
used to discharge the used pallet from the tracks 14 as
it will be disclosed in detail later.
Referring to Figure 2 of the drawings, there is
shown a schematic side view of the feed end of the
slnter machine showing the lifting wheel 12 in the
process of transferring a pallet from the lower rails
to the upper rails of the sinter machine follo~ing a
pair of guide rails 19 located one on each side of the
sinter machine. It is to be understood that a series
of pallets would be moved together by the lifting
~5 wheel although a single pallet is illustrated~ A portion
20 of each guide rail is cut and equipped with the mechanism
10 for removi~g the pallets from the lifting wheel. ~he
portion 2n of each guide rail is pivotally mounted on a
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sup~ort 22 secur~d to the existing structure of the sinter
plant. ~he po.~tion 20. o~ e.ach.~uide .rail ~$ RiYoted b~ a~
hydraul~c cy~l~nder 24 whic~ is maunted on a support 26
attached to the e~isting structure of the sinter plant
and ~aving a piston connected to a movable bracket 28
which ~s itself connected to a rod 30 pivotally mounted
to the lower end of the guide rail portion 20. The lower
end of each.guide rail portion 20 is provided with a
locking device 3~ for securing it to the remaining portion
of the guide rail during normal operation. A clamping
mechanism including two jaws 34 operated by an hydraulic
cylinder 36 is mounted on each guide rail portian 20.
A safety bar 38 is provided for locking the jaws in the
open position.
As a ~irst step in the operat;~.on of th.e pallet
changing apparatus, locking devices 32 are released to
free the guide rail portions 20 and safety bars 38 are
also released allowing operation of the hydraulic
cylinders 36 to clamp the pallet axles behind wheels
40. The h~draulic cylinders 24 are then operated to raise
the pallet from the li~ting wheel as sho~n i~ Figure 3 of
the drawingsO
As a second s.tep in the operation of the pallet
changing apparatus, the pair of tracks 14 is positioned
underneath the wheels of the pallets. In the present
em~odiment of the invention, the end of each track which
is close to the sinter machine is supported by a structure
4~ ~hich is pivotally connected at one end to the side of
the track and at its other end to a base 43 on the floor
and is operated laterally by the piston o a hydraulic
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cylinder 44 (Figure 11 ta swing that end of the track
into alignment ~th.the guide rail 20 to so mo~e that
end o the track underneath the wheels 40 of the pallet.
The end of each track ~lich.is remote from the feed end
o~ the sinter machine is connected to the piston of a
hydraulic cyli:nder 46 which is operated to rais~ that
end of the track ~rom ground level to the level of stand
16, To lower the pallet onto the tracks 14 hydraulic
cylinders 24 are operated in the reversP direction.
Hydraulic cylinders 36 are subsequently operated in the
reverse direction to unclamp the used pallet.
As a third step in the operation of the pallet
changing a~paratus, the pallet is rolled out manually
to contact an end stop 48 ~hich is located at the end
of each track 14. As shown in Figures 4 and 5, each end
stop 48 is mounted on a shaft 50 which is pivotally
mounted in lugs 52 secured to the outside walls of each
track. The end stops are manually operated to the
position illustrated in Figures 4 and 5. When the pallet
is in contact with end stops 48, the hydraulic cylinders
46 are operated to lo~er the tracks to the floor level
as shown in Figure 6 of the drawings, After lowering of
the tracks 7 the pallet (which weights abaut three tons)
exerts sufficient pressure to make the release of the
end stops difficult if not impossible. As shown more
clearly in Figure 7, the centre stop 18 is therefore
operated by an hydraulic cylinder 54 mounted on the
sinter ~achine supporting structure to release the
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pressure on the end stops 48 which may then be manually
pivated out oE the way, r'h~ hydr~ulic cylinder 54 i5
subsequently released to let tKe pallet roll out to the
position shown ~n dashed line.
The la~t step in the OperatiQn of the pallet changiny
apparatus is to introduce a ne~ pallet, which is preferably
positioned on the stand 16 in advance, into the sinter
machine. To that effect, the ends of the tracks 14 are
raised to the level of the stand and the new pallet is
advanced ~y hand against contact pallst stoppers 56 as
shown in Figure 8. The contact stoppers not only prevent
the pallet from overspeeding but also provide the added
bene~it of straightening and aligning the pallet t SO as
to facilitate clamping. As shown in Figures 9 and 10,
only in order to si~lplify the drawings, each pallet
stopper 56 is mounted on a shaft 58 which is pivoted in
lugs 60 secured to the side of each track. Each pallet
stopper is operated by an air actuator 62 through a piston
64 connected to an arm 66. Once the pallet is properly
ali~ned, the contact pallet stoppers are released and
the pallet pushed against ~inal stoppers 68 located one
on each track and operated by a mechanism (not shown)
identical to the one illustrated in Figures 9 and 10.
The cylindrical cyllnders 24 and 36 are then operated to
clamp the new pallet. The hydraulic cylinders 46 are
subsequently operated to lower the end of the tracks
remote ~rom the sinter machine to ground level. The
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hydraulic cvlinders 44 connected to the track supporting
structures 42 are also operated to rnove ~he tracks out
of the way 50 that the new ~allet may be inserted into
the liting wheel by operatian o~ the hydraulic cylinders
24. The h~draulic cylinders 36 are finally operated to
release the jaws 34 and the safety bar moved dawn -to lock
the jaws in the open pQsition as shown in Figure 11 of
the drawings.
Although the invention has been disclosed with
reference to a preferred embodiment, it is to be under-
stood that various alternatives to such embodiment are
envisaged within the scope of the following cla;ms.
