Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to a lifting and shifting
apparatus for lifting and substantially linearly displacing or
shifting an upper body in relation to a lower body, particularly
for :Lifting and shifting the upper sweep portion of a cistern in
relation to its lower sweep in the construction of a cylindrical
cistern. The invention particularly relates to such a device for
use in the erection of large cylindrical plated cisterns, the
plates being arranged along a helix in the sweep, which is built
up to the desired height by new plates being added at its lower
end simultaneously as the sweep is shifted upwards along the
helix. This method of erecting a cylindrical cistern is described
inter alia in the U.S. patent specifications 2,866,261 and 3,182,958.
According to the first-mentioned patent specification, geared
motors are used to drive the sweep upwards along the helix or screw
line. According to U.S. patent 3,182,958, the upper sweep is
driven with the aid of a plurality of jacks arranged between the
lower edge of the upper sweep and the upper edge of the lower
sweep. All these jacks lift the upper mantle simultaneously and
then tip forward in the direction of the screw line, the mantle
thus being rotated upwardly. The arrangement with jacks is cheaper
than a plurality of geared motors, but can cause problems in the
form of shock stresses at the end of each forward shift. It is
further known from U.S. patent specification 4,078,295 to support
the upper sweep with the aid of rollers in order to shift it for-
ward along the screw line, these rollers being caused to roll inplanes sloping forwards-downwards. In this case the sweep is
first lifted and then rolled downwards-forwards under its own
weight. The rolling movement is arrested by the upper sweep
knocking against the lower one, giving rise to troublesome shocks.
Alternatively, the upper sweep portion glides along the lower one
with great wear as a result. Control of movement is poor.
The purpose of the present invention is primarily to
avoid these disadvantages with an apparatus allowing a smooth and
controlled lifting and shifting movement which is not terminated
by a heavy shock and which does not cause wear as a result of any
scuffing movement of the sweep edge. In accordance with the in-
vention, this is achieved in that there is provided an apparatus
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for lifting and substantially linearly displacing or shifting an
upper body in relation to a lower body, particularly for lifting
and ~,hifting the upper sweep portion of a cistern in relation
to its lower sweep in the construction of a cylindrical cistern,
characterized in that a support member, resting against the lower
body, has an upwardly facing track, in that a lift member intended
for coaction with the upper body has a downwardly facing track
sloping forwards-downwards in the direction of the shifting
motion, the lift member being movable vertically as well as in
the direction of the shifting motion in relation to the support
member, in that a shift member arranged movable in relation to
the support member and lift member has two tracks, each arranged
parallel to, and coacting with the respective one of said tracks;
in that a shifting mechanism, acting between the support member
and the shift member, is adapted for giving the shift member
reciprocating motion relative to the support member; in that the
apparatus includes means which, under a first phase of the for-
ward travel of the shift member in the shifting direction of the
upper body, prevents the lift member from participating in this
movement, whereby the lift member is given a lifting movement,
and in that the apparatus also includes means adapted for also
shifting the lift member under continued motion forwards of the
shift member and during return motion of the shift member to
shift the lift member only during a terminating portion of its
movement, whereby the lift member is first allowed to lower the
upper body in its shifted position.
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The initial lifting motion of the upper sweep is thus
provided by a kind of wedge action, the sweep being maintaine~
unmoved in the shifting direction. In accordance with a pre-
ferred embodiment of the invention, this is achieved by the track
of the member which is lifted (referred to hereinafter as the
lift member) sloping just sufficiently in the shifting direction
so that the resultant acting on the upper body in the forward
direction is less than the resistance to movement counter-
acting the movement of the upper body. This resistance is
generated, e.g. in plated cisterns, by the friction between the
bottom portion of the sweep and guide rollers which guide this
portion laterally.
The shift member is preferably formed as a wedge, there
being rollers arranged between coacting tracks. According to a
preferred embodiment of the invention, arresting means are further-
more arranged between the shift member and the lift member and
adapted for coming into action after a first phase of the shift
member travel. The lift member is thus moved by the shifting
mechanism of the shift member, special members providing travel
for this purpose thus being dispensed with.
An embodiment of the invention is described below while
referring to the accompanying drawings, where Fig. 1 illustrates
from one side and partly in section along the line I-I in Fig. 5
a lifting and shifting apparatus in accordance with the invention,
mounted between the upper and lower sweeps of a cylindrical
cistern under construction. In a corresponding way, Figs. 2, 3
and 4 illustrate the apparatus in other operational positions.
Fig. 5 is a section along the line V-V in Fig. 1 and to a larger
scale.
The support member 1 of the apparatus is hung on the
upper edge 3 of the lower cistern sweep 2 and is formed as a
channel-shaped frame, the web of which is formed by two hori-
zontal spac~r plates 4,` each having one end welded to a square
tube 5 running along the lower sweep 2. The spacers 4 rest on
the sweep edge 3, and in the initial position, illustrated in
Fig. 5, the lower edge 7 of the upper sweep 6
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rests on said spacers 4. The square tube 5 thus forms one
channe~ flan~e, while the other flange is formed by one or
mo.re legs 8 attached to the spacers 4 on the other.side of
the lower sweep 2. Set screws 9 extend.through threaded holes
5 in the legs 8 and can be tightened against the sweep 2 for
locking the support member or frame 1 thereto.
On the upper side of each spacer 4 there are two guide
rollers 10,11 carried by stub shafts 12,13 and arranged on
either side of the upper sweep 6 to guide it laterally. Above
( 10 this square tube S the edges of the spacers 4 ~acing towards
each other are each provided with a perpendicularly upstand-
ing guide block 14, the upper face of which is formed as a
c slide surface 15 A carrier member 16 rests on the slide
surfaces 15 and extends parallel to the.up~er sweep 6, and is
15 formed at its bottom edge such that it is not displaceable
longitudinally along the sweep 6. On the other hand, the
carrier body 16 can slide to and from the sweep 6 on the
slide surfaces lS. The carrier body 16 is acted on by a
spri~g-loaded p.in 17 in a direçtion towards the sweep 6, this
20 pin being.carried in a post 18 upstanding from the square
tube 5 between the spacers 4. The upper edge of the carrier
member 16 has a.track 19 for a plurality of rollers 20.
Associated with the support mem~er 1 there is also a post 21
C! on the right-hand end of the carrier body 16 in Fig. 1, the
upper end of this post being formed as a spring anchorage,
its lower portion forming a mounting for one end of a single-
~- acting hydraulic cylinder 22, extending parallel to the
track 19.
There is a shift means in the form of a wedge 24,
resting with its downwardly facing track 23 on the rollers 20
of the track 19. As with the carrier member 16, the wedge 24
is made as an elongate thick plate parallel to the upper
sweep 6 ana also having an upper track 25 carrying rollers
20, similar to the track 19. The track 25 slopes downwards to
the left in Fig. 1. At the right-hand end of the wedge 24
there is.a conical recess, not shown specifically. The
rounded end of a push rod 26 rests in the recess, the other
end of the rod, which is also rounded, resting in a conical
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recess in the piston 27 of the hydraulic cylinder 22. The
push rod 26 is not guided in the mounting of the cylinder 22
to the post 21, but runs through it with large free play,
allowing for lateral movement of the wedge 24 in relation to
the cylinder 22.
A rod 28 projects in the longitudinal direction of the
wedge 24 from the left-hand end of the latter and carries at
its end an upstanding post 29, the upper end of which is
formed as a spring anchorage. A tension spring 30 is mounted
( 10 between this anchorage and the anchorage in the post 21 to
keep the wedge 24 engaged against the push rod 26.
A lift member 32 with a U-shaped cross section, where
~ the joining portion of the U forms a downwardly facing track
- 31, rests on the rollers 20 of the upper track 25. The track
1~ 31 extends parallel to the upper track 25 of the wedge 24 to
carry the lift member 32, which thus hangs as a yoke with its
legs 33 and 34 on either side of the wedge 24 and carrier
member 16. The leg 33, closest to the sweep 6, has its middle
portion extended downwards and bent`to form a lifting hook 35
20 extending in between the edges 7 and 3 of the sweep portions
6 and 2. In the initial position illustrated in Fig. 5, the
lift member 33 with its lift hook 35 assume their lowest
position, in which there is a vertical~clearance between the
C bottom edge 7 of the upper sweep and the upper face of the
hook 35 under the-edge 7. The lift hook 35 forms an angle of
~ somewhat less than 90 to the leg 33. When the sweep 6 is
C" lifted by the hook 35, the moment thus formed is taken up by
the sweep and the hook is locked in position against the
sweep so that it cannot slip out. At the beginning of the
30 lifting movement, the spring-biassed pin 17 answers for the
leg 33 lying tight against the sweep 6.
The rod 28 of the wedge 24 extends out between the legs
33 and 34 of the lift member 32. The left-hand ends, in
Fig. 1, of the legs 33 and 34 are mutually united by plates
35 36 which allow through assage of the rod 28 but form a stop
for the left-hand end of the wedge 24. The push rod 26
extends outwards between the legs 33 and 34 at the right-hand
end of the lift member 32 in Fig. 1.
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The edges 3 and 7 of the sweeps 2 and 6 run helically
and can slope upwards, for example, to the left in Figs. 1
ana 3 at an angle ~ of 1 - 2. The track 19 of the carrier
member 16 is parallel to the upper edge 3 of the lower sweep
5 2. The angle ~ between the upper and lower tracks 23 and 25
of the wedge 24 will be sèlected small enough for the
friction and other forces counteracting the shifting movement
of the upper sweep 6 to exceed the resultant of the sweep
weight acting in the shifting direction. In practice, the
10 taper angle ~ should be chosen less than abou~ 5 for a < 2.
For the construction of a cistern, a plurality of
lifting and shifting apparatuses in accordance with the
C figures are arranged at equal spacing around the sweep edge.
If each apparatus is dimensioned for about 10 tons, for
15 example, the spacing between the apparatuses can be 2 - 3 m,
depending on the buckling tendency of the sweep plating. All
the hydraulic cylinders 22 of the apparatuses are connected
via pressure lines 37 in parallel to a common hydraulic
pressure source, and thus operate in unison. The clearance
20 between the lift hook 35 and the sweep edge 7 can be about
2 mm.
The apparatus functions in the following manner. Figs. 1
and 5 illustrate the initial position in which the hydraulic
cylinder 22 is unpressurized and the tension sprinq 30 has
25 returned the wedge 24 to its right-hand end position. The
lift member 32 has thus also been lowered to its lowest
C position and has also assumed its right-hand end position.
When the lifting movement is to be started, the hydraulic
cylinder 22 is pressurized, the piston 27 and thereby the
30 wedge 24 being shifted to the left a distance b to the
position illustrated in Fig. 2. During this wedging movement
the lift member 32 is not shifted and thereby neither is the
sweep 6 in the direction of shift travel, but is solely
provided with a vertical lifting movement c, Fig. 2. The
35 lifting distance c is suitably selected at about 8 mm, which
is obtained with a piston and wedge travel b of about 190 mm.
In the position illustrated in Fig. 2, at the end of the
travel b of the wedge 24, the left-hand end of the wedge has
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just come lnto engagement against the stop plates 36 on the
liEt member 32. For continued piston travel d! the wedge 24
is shifted further to the left, taking with it the lift
member 32 by means of its engagement against the plates 36.
The wedge 24 now travels on the rollers 20 on the track 19
of the carrier member 16, whereby the upper sweep 6 is
shifted along and parallel to the lower sweep 2. The motion
is continued until the piston 27 has reached its left-hand
end position in the cylinder 22. The shifting movement is 10 denoted d, and this position is shown in Fig. 3. The
effective shift travel can amount to about 100 mm.
A lifting movement c of about 8 mm is thus obtained
{~ with a total piston movement b f d of about 240 mm, which
signifies a large force ratio. Smooth lifting and lowering
15 movements are thus obtained and the cylinder 22 can be given
small dimensions, e.g. a diameter of merely 30 mm for the
above-mentioned lifting force of 10 tons.
After terminated shifting motion, the pressure in the
hydraulic cylinder 22 is reduced. The wedge 24 is moved to
20 the right under the action of the weight of the sweep 6 and
the bias of the spring 30. The sweep 6 does not accompany
this movement but is lowered perpendicularly to the track 19.
The motion will be smooth as a result of the large ratio
+ d. When the sweep 6 has been lowered so that its bottom
2S edge 7 comes to rest on the spacers 4, the position as shown
in Fig. 4 has been reached. When the pressure is further
C reduced in the cylinder 22, the wedge 24 as well as the lift
member 32 are returned to their right-hand end positions
under the action of the tension spring 30, after which the
30 initial position shown in Fig. 1 has once again been reached.
