U.S. patent number 3,858,926 [Application Number 05/381,886] was granted by the patent office on 1975-01-07 for vacuum lifting device.
Invention is credited to Ludger Ottenhues.
United States Patent |
3,858,926 |
Ottenhues |
January 7, 1975 |
VACUUM LIFTING DEVICE
Abstract
A vacuum lifting apparatus is composed of a plurality of
side-by-side elongated segments which engage an article to be
lifted by collectively conforming to the surface of the article
through the force of gravity. The segments are connected by a
plurality of seals which project from a main plate and a resilient
rim encircles the segments and seals. Tie rods extend from each
segment to a common hub and are immovably clamped together after
the article has been engaged, thereby locking the segments in
position while defining a desired curved configuration.
Inventors: |
Ottenhues; Ludger (4407
Emsdetten, DT) |
Family
ID: |
23506754 |
Appl.
No.: |
05/381,886 |
Filed: |
July 23, 1973 |
Current U.S.
Class: |
294/189;
294/65 |
Current CPC
Class: |
B66C
1/0231 (20130101); B66C 1/0256 (20130101); B66C
1/0293 (20130101); B66C 1/0287 (20130101); B66C
1/0281 (20130101) |
Current International
Class: |
B66C
1/00 (20060101); B66C 1/02 (20060101); B66c
001/02 () |
Field of
Search: |
;294/64R,64A,65,86
;214/1BS,1BT,1P,1PA,8.5D,65SG |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schacher; Richard A.
Assistant Examiner: Rowland; James L.
Attorney, Agent or Firm: Fitch, Even, Tabin &
Luedeka
Claims
What we claim is:
1. In a vacuum lifting apparatus for lifting articles having an
axially symmetrically curved surface, a vacuum lift device
comprising: a flexible main plate, a plurality of rigid
side-by-side elongated segments carried on said main plate for
angular movement relative to each other to define a curved
configuration adapted to the curved surface of the article, a
plurality of seals associated with said segments and projecting
from said main plate, a sealing rim of resilient material
projecting from said main plate to engage said article and to form
an air seal therewith and encircling said segments and said seals,
tie rod means pivotally connected to the outer side of segments at
first ends thereof, opposite ends of said tie rod means extending
toward a common location from said segments for positioning
relative to one another with angular movement of said segments, and
means for locking said tie rod means at said common location at
given positions to hold said segments at said angular relationships
while defining a desired curved configuration.
2. A vacuum lifting apparatus in accordance with claim 1 in which
said opposite ends of said tie rod means have elongated holes
therein and in which said locking means comprises a stationary hub
and a bolt extending through said hub and elongated holes in said
tie rod means for clamping said tie rod means in an immovable
condition relative to said hub.
3. A vacuum lifting apparatus in accordance with claim 2 in which
spacer discs are provided between adjacent tie rod means, and which
said means for locking said tie rod means comprises a pivot arm
connected to said bolt, rollers secured to said pivot arm for
engagement with said hub for engagement therewith during turning
said pivot arm between a locking and unlocking position.
4. A vacuum lifting apparatus in accordance with claim 1 in which
said vacuum lifting device is circular in shape, said segments
being arranged with segments of decreasing length in an outward
direction from the center of said circular configuration.
5. A vacuum lifting apparatus in accordance with claim 1 comprising
a plurality of said vacuum lift devices aligned in a row, a common
vacuum cylinder for producing for each of said lift devices and an
orienting device for aligning said row of lift devices relative to
the axis of said axially symmetrically curved surface.
6. A vacuum lifting apparatus in accordance with claim 5 including
an additional vacuum pump connected to said vacuum lifting
devices.
7. A vacuum lifting apparatus in accordance with claim 5 in which a
transverse rail is provided for supporting said row of vacuum lift
devices, a plurality of bolts are provided for connecting said lift
devices to said transverse rail, upper springs are provided between
the upper ends of the bolts and said rail and lower springs apply a
biasing force between said rail and said tie rod means.
8. A vacuum lifting apparatus in accordance with claim 1 including
a transverse rail, a plurality of orienting devices mounted on said
transverse rail, each of said orienting devices comprising
laterally protruding adjusting arms, rollers mounted on the lower
ends of said adjusting arms, the upper ends of said adjusting arms
being pivoted to a stationary point with respect to said transverse
rail, a plurality of push rods, each of said adjusting arms being
connected by one of said push rods to an adjusting arm at first end
thereof, a two-piece transverse web, each of said webs being
connected to the other ends of one of said rods and adapted to be
lifted from said transverse rail by its associated push rod, a
spring means applying a force to hold said transverse webs against
said transverse rail, an elongated guide slot extending vertically
on said transverse rail, a pin means guided within said guide slot
and connected to said transverse rail, and a downwardly directed
hook on each of said transverse webs including an inwardly directed
tip to engage around the lower outer edge of the transverse
rail.
9. A vacuum lifting apparatus in accordance with claim 1 in which a
cylinder means provides a vacuum for said lift device, a piston is
mounted in said cylinder means for pulling by a hoist, a flexible
strand means is connected at a fixed end to said cylinder means and
is connected at its opposite end to said hoist, guide sheaves
carried by said piston and having said flexible strand means
extending parallel to the direction of movement of the piston
between the ends fastened to said cylinder and said guide sheaves.
Description
The present invention relates to a vacuum lifting device for the
lifting of articles having an axially symmetrically curved surface,
by means of a holding vacuum.
Vacuum lifting devices for the lifting of articles having planar
surfaces are known. Heretofore, the lifting of articles having a
curved surface was always unsuccessful for the reason that the
holding or suction cup could not be given a shape which would adapt
itself to various curvatures.
It is the object of the present invention to provide a vacuum
lifting device for the lifting of articles having curved surfaces,
which device, in particular, renders it possible to safely lift
articles having axially symmetrically surfaces of most varied radii
of curvature, and to safely hold such articles in the lifted
position.
The lifting device according to the invention should be of simple
construction, easy to operate and economical in manufacture. It
should be of light weight and adapted to fit equally well to
articles having an inner or concave curvature and such having an
outer or convex curvature, and it should be capable of lifting even
extremely heavy articles.
According to the present invention, this object is solved in that
in the vacuum lifting device a suction cup is placed upon the
surface of the article to be lifted, whereby the suction cup curves
under the action of gravity and conforms itself to the surface of
the article such that segments of the suction or holding cup rest
uniformly on the curved surface, the configuration of the suction
cup is fixed in this position, a holding vacuum is produced between
the suction cup and the surface, and the article to be lifted is
raised by applying a pulling force onto the suction cup.
Accordingly, the device according to the invention comprises the
following components: A suction cup comprising a plurality of
side-by-side extending, flat and elongated segments and a seal
positioned underneath and/or between them; a sealing lip extending
around the segments; lower tie rods pivoted to each segment and
each having an elongated hole in the end remote from the segment;
and a hub passing through said elongated holes and permitting the
tie rods to be clamped.
For the uniform take-up of load of the separate segments during the
curving of the suction cup, the tie rods engaging on the individual
segments are moved such that they are shifted relative to each
other and retained against each other in immovable condition after
the application of the suction cup.
In order to compensate for minor irregularities, at least the
outermost tie rods are pivoted to the segments through bolts guided
within elongated holes. In order to facilitate the clamping of the
tie rods after the application of the suction cup, spacers may be
fitted between the tie rods, and the hub may be traversed by a
transverse bolt which is secured on a pivot arm. The end of the
pivot arm is supported by rollers, whereby the axis of rotation of
the rollers is movable somewhat beyond the center axis of the
hub.
In order that a number of suction cups according to the invention
can be arranged in side-by-side relation for the lifting of heavy
loads, a pair of the tie rods engaging on corresponding segments
are secured to a dog or claw, whereby the dog through a bolt and
elongated holes engages on a transverse rail which has positioned
thereon a plurality of suction cups in side-by-side relation.
Rubber cushions are provided between the bolts of the dog and the
transverse rail.
In order to render possible a good sealing action of the continuous
sealing lip, the suction cup is preferably of circular
configuration, while the segments arranged in side-by-side relation
become increasingly shorter in outward direction.
In the case of articles of great length, such as pipes, it has been
found that a single suction cup does not always provide a
sufficient suction force. Accordingly, it is contemplated to
provide a lifting device capable of safely lifting and retaining
even very long tubular bodies of high weight and having great wall
thicknesses. Nevertheless, the lifting device according to the
invention should be of simple construction, universally useful and
economical in operation.
In particular, the vacuum lifting device also should be adapted to
be automatically aligned with tubular bodies or articles, such that
each separate suction cup can be applied precisely along the axis
of the cylindrical article. Hereby, the suction cup should adjust
itself automatically, i.e., without any manual aid, to the
cylindrical surface when the cup is lowered.
This additional object is solved according to the invention by a
lifting device comprising means as described in greater detail in
claim 6.
Advantageously, the suction cups by means of stay bolts may be
suspended from a transverse rail having protruding flanges, and the
stay bolts may be supported relative to the transverse rail by
coiled springs from below and by dished springs from above.
In order to align the vacuum lifting device precisely along the
center axis of the cylindrical article, preferably the vacuum
lifting device according to the invention comprises at least a pair
of orienting devices mounted on the transverse rail and having
laterally protruding adjustment arms carrying rollers at the lower
ends thereof, which arms are pivoted at their upper ends on a pivot
point being stationary with respect to the transverse rail, and
pivotally connected to pushrods between their ends, the upper ends
of said pushrods being connected to a two-piece transverse web
adapted to be lifted off the transverse rail under the force of a
spring and adapted to be collapsed about a center joint guided
within an eye of the transverse rail, said transverse web having
attached to its two legs a downwardly directed hook including an
inwardly extending tip, which hook engages around the lower outer
edge of the transverse rail.
Generally, chains or cables are used for lifting the vacuum devices
including vacuum cylinders. This results in the disadvantage that
the angle of inclination of the chains or cables relative to the
cylinder increases such that the pressure force applied to the
cylinder decreases.
Therefore, it is proposed to have the chains or cables pass around
guide rollers or sheaves at the cylinder, which sheaves are mounted
on the cylinder, whereby the draw gear (chains or cables) extends
parallel to the direction of movement of the piston in the region
between the pivot points on the cylinder and guide sheaves.
In the following, exemplary embodiments of the invention are
explained in greater detail by referring to the accompanying
drawings, wherein:
FIG. 1 is a part elevational view of a vacuum lifting device
according to the present invention;
FIG. 2 shows a first embodiment of a suction cup in relieved
condition;
FIG. 3 shows the suction cup of FIG. 2 in its curved condition;
FIG. 4 is a plan view of the suction cup of FIG. 2;
FIG. 5 is a cross-sectional view through the suction cup of FIG.
2;
FIG. 6 shows a part elevational view of a modified embodiment of a
suction cup;
FIG. 7 is a cross-sectional view through a suction cup suspended
from a transverse rail;
FIG. 8 is a cross-sectional view through an orienting device
connected to the transverse rail and
FIGS. 9a and 9b are sectional views of a vacuum cylinder in two
different positions.
As shown in FIG. 1, the vacuum lifting device according to the
invention comprises a plurality of vacuum suction cups 1 which are
mounted in series and in side-by-side relation on a transverse rail
36 which, in turn, is adapted to be raised by means of a vacuum
cylinder 2 through a hoist. The hoist is connected to a piston of
the vacuum cylinder 2 through singly sheaved chains (FIGS. 9a,b ).
When the hoist is raised the piston is drawn upwards within the
cylinder 2 so as to produce a high vacuum. During the raising
operation, the vacuum generated within the cylinder is transmitted
through not illustrated hoses to the individual suction cups where
such vacuum produces the requisite suction force.
In its operational condition (FIG. 3), the suction cup 1 contacts a
cylindrical article 5, e.g., a pipe. In its relieved condition, the
suction cup has the configuration shown in FIG. 2.
The suction cup comprises a plurality of adjacently disposed, flat
segments 3 which are parallel to each other and of which the
outermost segments are shorter than the inner segments, such that
the segments in their curved condition jointly form a circular
disc.
Sealing elements 4 are secured or vulcanized between and/or below
the segments, such that a sealing and flexible plate is formed
under the suction cup.
The segments 3 and the seal 4 are surrounded by a continuous
sealing lip 35 which prevents air from penetrating into the vacuum
space under the sealing elements 4.
The individual segments 3 carry webs 20 which have fitted into them
bolts 9 extending along the respective segment. Lower tie rods 6
are pivoted to the bolts 9, which tie rods extend from the bolts 9
to a central hub 8 being movable within an elongated hole of the
lower tie rods 6. A normal circular hole is provided for the inner
tie rods only because the inner tie rods 6 are the only members
which need not shift relative to the hub 8.
Spacer discs 11 (FIG. 4) are provided between the separate tie rods
6 which are arranged symmetrically on either side of the center
line of the suction cup. By the provision of a thrust sleeve 21
which acts against the next inner tie rod 6, the hub is held
stationary relative to one of the outer tie rods 6. At its opposite
end, the hub 8 carries a clamping device 50 by means of which the
tie rods 6, with the exception of the tie rod on the left side in
FIG. 4, may be clamped together as a stack. The clamping device 50
comprises a pivot lever 13 which is pivoted to the end of the hub 8
through a bolt 12.
The flanges of the lever 13 carry rollers 14 which press against
the outermost one of the tie rods 6.
When the hand lever 13 is pivoted in the direction of the arrow by
means of the handle 22, the lever 13 cams on the rollers 14 and
thereby draws the hub 8 outwardly, such that the tie rods 6 are
immovably clamped or locked to each other as a stack. When the
pivot lever 13 is pivoted beyond the outermost tension point, it is
automatically jammed since in this condition the transverse joint
between the flanges abuts the hub 8.
In the manner described above, it becomes possible to lock the tie
rods in most simple manner in their position adapted to the surface
of the curved article. The locking can be effected also by other
means, e.g., by remote control, hydraulically, pneumatically, or by
electromotoric or mechanical means. Hereby, the hydraulic or
pneumatic energy may be produced also by the extension movement of
the piston from the vacuum cylinder 2 if, for instance, a hydraulic
or pneumatic cylinder is mounted parallel to the vacuum cylinder 2
and connecting conduits are provided between the transmitting and
the receiving pistons on the suction cups. Also, the expert is
aware of a number of other measures for the clamping operation.
It has been found to be advantageous to pivot the tie rods 6 to the
bolts 9 by means of elongated holes the longitudinal direction of
which extends parallel to the segments 3 in their horizontal
position. These elongated holes provide for an improved force
transmission to the individual segments and, at the same time,
provide a compensation for slight surface irregularities.
In order to lift heavy loads, it is necessary to arrange a number
of suction cups serially in side-by-side relation. In this case
(FIG. 3), a transverse rail 36 carries the suction cups through
bolt 16, whereby the respectively outermost tie rods 6 which are
secured to the innermost one of the segments 3, are attached to a
dog 15. The bolt 16 passes through an elongated hole in the
vertically extending flanges of the dog 15 so as to be able to
compensate for minor distance irregularities between the separate
suction cups. Rubber cushions 19 are positioned between the
horizontal bottom wall of the dog 15 and the transverse rail 36,
which cushions transmit the power to the transverse rail 36 while
compensating for a certain clearance.
In the space confined under the seal 4, a vacuum is produced either
by an additional vacuum pump or by the vacuum cylinder 2 via
conduits. The vacuum cylinder which is positioned above the
transverse rail 36, is expanded when the hoist is raised and
thereby produces the vacuum required for the lifting of the
article. An additional vacuum pump is required in the case that the
device is to be accommodated to the lifting of extremely heavy
loads. The additional pump is driven by external means, i.e., by an
electric motor or the like, but not through the linkage.
Surprisingly, with the device described above it is not only
possible to lift the articles, but also to safely hold or suspend
them for an extended period of time. To this end, it is necessary
that the suction cup conforms itself to the surface from its
horizontal position as shown in FIG. 1, when it is applied to the
article 5 to be raised, whereby the tie rods adjust themselves to
their respective position. Hereby, the hub 8 is shifted within its
elongated holes 7. As soon as such adjustment has been effected,
the tie rods are clamped against each other in immovable condition
so as to uniformly take up the lifting force. Thereafter, the
device is evacuated and the article is lifted.
A rough calculation and a test show that the suction cups according
to the invention are capable of lifting even pipes having wall
thicknesses of from 20 to 30 centimeters.
In the modified embodiment shown in FIGS. 6 to 8, the modification
resides particularly in the suspension and orientation of the
suction cup. The construction of the suction cups per se is
substantially identical to that according to FIGS. 2 to 5.
The embodiment according to FIG. 6 uses other suspensions than in
the example of FIG. 3. At the point of attachment of the suction
cup 1, the transverse rail 36 includes laterally protruding flanges
38 having bores 42, whereby stay bolts 37 are supported relative to
the flanges 38 at their upper ends by means of dished springs 40
and at their lower ends by means of coiled springs 39. In this way,
the suction cups 1 may be adjusted relative to the transverse rail
36 without causing the applied lifting power to become non-uniform,
since the dished springs 40 are of substantially greater stiffness
than the coiled springs 39.
Upon placing the vacuum lifting device upon a tubular body or
article, the suction cups - as described above - conform themselves
to the surface configuration of the article to be lifted In this
position, in the illustrated embodiment a common shaft 33 extending
from one suction cup 1 to the other through universal joints is
rotated by means of a handcrank 41, which shaft is mounted with
threaded portions within the individual clamping devices 50 of the
suction cups 1. When the shaft is rotated, the clamping devices 50
are pivoted in the clamping or locking direction, and the
individual tie rods 6 of the suctions cups 1 are clamped
together.
In order to release the clamping engagement, the shaft 33 is
rotated in the opposite direction. Thereby, the clamping device 50
again moves through its dead center and relieves the clamping force
applied to the tie rods 6.
In view of the fact that most frequently a number of articles of
identical curvatures are lifted one after the other, the rapidly
performed clamping and releasing does not involve any substantial
expenditure of work.
In order that a tubular article may be properly lifted by means of
the suction cups 1, the suction cups during their placement must be
precisely aligned axially over the tubular article. In order to
effect such precise axial alignment, both arms of the transverse
rail 36 have adjacent the outer ends thereof one orienting device
34 each for the adjustment or orientation of the lifting
device.
As shown in FIG. 8, each orienting device 34 has a pair of
adjusting arms 52 carrying rollers 51 at the lower ends thereof and
having their upper ends pivoted to a common pivot point 55. The
adjustment arms 52 are angled at their lower ends. At this point,
push rods 54 are pivoted the upper ends of which are pivotally
mounted on a transverse beam 53.
The transverse beam 53 comprises a pair of arms which are pivotable
relative to each other about a center joint 57. Each of these arms
has secured thereto a downwardly projecting hook 59 which engages
under the lower side of the transverse rail 36.
The axle of the center joint 57 is adpated to be moved vertically
upwards and downwards within an eye 58 secured to the transverse
rail 36. The center joint 57 is retained by a spring 56 in its
position abutting the transverse rail 36.
The aligning or orienting operation by employing the orienting
device 34 is effected as follows:
During the normal placement of the vacuum lifting device, one of
the adjustment arms 52 will first contact the surface and be
deflected thereby. This deflections is transmitted via the pushrod
54 to the transverse beam 53 such that its arm remote from the
pushrod 54 is raised and moves the hook 59 away from the transverse
rail 36. Now, the movement of the transverse beam 53 is limited by
the fact that a lug 64 mounted to the inner upper end of the
pushrod 54 contacts the hook 59 thereby preventing further upward
movement of the adjustment arm 52.
Now, the system which has been rendered stiff in this way aligns
the transverse rail 36 with the center axis of the tubular article
5. Then, the roller 51 opposite the first roller 51, and, thus, the
adjustment arm 52 opposite the first adjustment arm 52, tend to
act, with a slight swinging movement, against the surface of the
article 5, thereby to effect a re-alignment towards the opposite
side, whereby, with the swinging motions becoming increasingly
smaller, the transverse rail 36 will be gradually aligned exactly
axially with the article 5.
After such alignment, both adjustment arms 52 are simultaneously
engaged on both sides. During the further lowering of the vacuum
lifting device, the two pushrods 54 are simultaneously moved in
upward direction, whereby both hooks 59 are concurrently released
from the underside of the transverse rail 36. It is only in this
aligned condition that the center joint 57 can be moved upwards
within the eye 58 against the force of the spring 56. The suction
cups 1 being aligned as a whole, can then be placed onto the
tubular article 5.
Under these circumstances, the force of the spring 56 may be very
small because it need only perform a fixing function of the center
joint 57 until alignment is obtained, whereby the thrust force
proper is taken up by the hook 59 in each case.
It has been found that a simple pivoting, acting with a spring
force, of the adjusting arms on the transverse rail does not
require so high a spring force for the alignment that the sucking
function of the suction cups would be affected or the lifting force
exerted by the suction cups would be removed in part. In a manner
being surprising to the expert, with the proposed orienting device
34 it is possible with very low spring forces only, to obtain a
proper alignment of the complete system of the suction cups 1 on
the tubular article 5. In another embodiment of the invention, a
single suction cup may be mounted under the vacuum cylinder, which
suction cup carries on both sides thereof an orienting device each,
e.g., on the transverse rail.
FIG. 9 shows in detail a vacuum cylinder 2 by means of which the
complete arrangement may be lifted and the suction cup may be
supplied with a vacuum. The vacuum cylinder comprises a cylinder in
which a piston 72 is sealingly guided. The sealing can be effected
either by smooth or grooved circular cord rings 86 or by a
diaphragm or membrane. The lower end of the piston 72 includes a
piston face 73 on which support arms 75 including guide sheaves 76
engage through intermediate members. The cylinder 2 has sealing
lips 74 at its lower end in order to protect the cylinder space
against the penetration of air from the outside when the piston 72
is moved upwards to thereby produce a vacuum. A draw gear, e.g., a
chain 77, a cable, a rope, a steel belt or the like, is passed
around the guide sheaves, which draw gear is pivoted to the
cylinder at 78. The pull is transmitted to the chain 77 through a
support ring 79 by a hoist, for example a crane.
Now, when the crane pulls up the support ring 79, the chain is
placed under tension and thereby draws the piston 72 in upward
direction via the guide sheaves 76. The tension of the chain 77 is
transmitted to the cylinder via the point 78, thereby urging the
cylinder in the opposite, vertical direction. This pressure action
provides an extremely good sealing function. The ends of the chain
between the pivot point 78 and the guide sheaves 76 extend parallel
to the direction of movement of the piston and, therefore, do not
change their direction with respect to the cylinder during a
movement of the piston. Accordingly, the magnitude of the force
exerted by the chain on the cylinder is independent of the already
effected piston stroke of the stroke which may still be
performed.
In a further embodiment of the cylinder, it is possible to pass the
draw gear repeatedly between the piston and the cylinder, thereby
to obtain a multiplication of the pressure force.
In an alternative embodiment of the method according to the
invention, the power transmission from the support ring to the
cylinder may be effected through levers which have a draw bar
pivoted thereto e.g., in the mid portion thereof, which draw bar,
again, is secured with its lower end to the piston and through
which the pull is transmitted to the piston.
In a further embodiment, the support ring is connected to racks
which, in turn, are in engagement with gears secured to the draw
bar of the piston. The gears are each in engagement with further
racks of the cylinders. Retraction of the racks results in rotation
of the gears and thereby produces a force which acts upon the racks
of the cylinder in pressing direction. In this embodiment, too, an
exactly vertically directed pressure force relative to the cylinder
is provided. By means of a plurality of gears (at least two gears),
any desired gear ratio of the force to be exerted can by
obtained.
* * * * *