U.S. patent number 3,833,251 [Application Number 05/295,634] was granted by the patent office on 1974-09-03 for longitudinally stiffened flexible lifter for arcuate objects.
This patent grant is currently assigned to Aerovac Corporation. Invention is credited to Jacob J. Creskoff.
United States Patent |
3,833,251 |
Creskoff |
September 3, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
LONGITUDINALLY STIFFENED FLEXIBLE LIFTER FOR ARCUATE OBJECTS
Abstract
A vacuum lifter is provided for arcuately shaped objects which
includes a flexible sheet having opposed parallel surfaces. A
supporting member is connected to one surface of the sheet and a
resilient sealing gasket is connected to the opposing surface of
the sheet about the periphery thereof. A source of vacuum is
provided and the sheet has a port through which the vacuum source
communicates. Stiffening means are connected to the flexible sheet
to prevent bending of the sheet about a line extending at an angle
transverse to the longitudinal extent of the plate. The lifter is
secured to an arcuate object by placing the gasket against the
outer surface of the object so that a partial vacuum is formed in
the compartment formed between the outer surface of the object, the
sheet and the gasket. The sheet accomodates a range of diameters of
arcuate objects by bending around its longitudinal axis to conform
to the diameter of the objects.
Inventors: |
Creskoff; Jacob J. (Wynnewood,
PA) |
Assignee: |
Aerovac Corporation
(Bala-Cynwyd, PA)
|
Family
ID: |
23138561 |
Appl.
No.: |
05/295,634 |
Filed: |
October 6, 1972 |
Current U.S.
Class: |
294/189;
294/65 |
Current CPC
Class: |
B66F
9/181 (20130101) |
Current International
Class: |
B66F
9/18 (20060101); B66c 001/02 () |
Field of
Search: |
;294/64R,65
;214/65SG,8.5D ;248/206,362,363 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Blunk; Evon C.
Assistant Examiner: Cherry; Johnny D.
Attorney, Agent or Firm: Caesar, Rivise, Bernstein &
Cohen
Claims
What is claimed as the invention is:
1. A vacuum lifter for arcuately shaped objects comprising a
flexible sheet which is formed of a flexible material and has
opposed parallel surfaces and a source of vacuum, said sheet having
a port through which said vacuum source communicates, a supporting
member connected to one surface of said sheet, a resilient sealing
gasket connected to the opposing surface of said sheet about the
periphery thereof, and stiffening means connected to said flexible
sheet to prevent bending of said sheet about a line extending at an
angle transverse to the longitudinal extent of said sheet, said
stiffening means comprising a plurality of closely spaced
longitudinally extending plates provided along the entire
transverse extent of said flexible sheet, said lifter being secured
to an arcuate object by placing said gasket against the outer
surface of said object so that a partial vacuum is formed in the
compartment formed between the outer surface of said object, said
sheet and said gasket, said sheet accommodating a range of
diameters of arcuate objects by bending around its longitudinal
axis to conform to the diameter of said object.
2. The vacuum lifter of claim 1 wherein said closely spaced
longitudinally extending plates are connected to the front and rear
surfaces of the flexible sheet.
3. The vacuum lifter of claim 2 wherein the longitudinally
extending plates connected to the side of said sheet that said
gasket is connected each have spacing means connected between the
plates and said sheet, said spacing means enabling a uniform
distribution of the partial vacuum in the compartment formed
between an object to be lifted, the gasket and said flexible
sheet.
4. The vacuum lifter of claim 1 wherein said gasket includes an
enlarged portion on one side of said lifter, said enlarged portion
being provided on the uppermost edge of said lifter when said
lifter engages an object to be lifted, said enlarged portion being
integral with said gasket and movable with respect to said sheet so
that said portion provides a fortified sealing area when said
object is lifted.
5. A vacuum lifter for arcuately shaped objects comprising a
flexible sheet having opposed parallel surfaces and a source of
vacuum, said sheet having a port through which said vacuum source
communicates, a supporting member connected to one surface of said
sheet, a resilient sealing gasket connected to the opposing surface
of said sheet about the periphery thereof, and stiffening means
connected to said flexible sheet to prevent bending of said sheet
about a line extending at an angle transverse to the longitudinal
extent of said sheet, said lifter being secured to an arcuate
object by placing said gasket against the outer surface of said
object so that a partial vacuum is formed in the compartment formed
between the outer surface of said object, said sheet and said
gasket, said sheet accommodating a range of diameters of arcuate
objects by bending around its longitudinal axis to conform to the
diameter of said object, said supporting member including an
arcuate plate which is connected centrally to said flexible sheet,
said arcuate plate including means for urging the transverse ends
of said lifter in an arcuate shape to facilitate seating of the
gasket against an arcuate object.
6. The vacuum lifter of claim 5 wherein said means for urging
includes a pair of leaf springs which extend through said arcuate
plate and urge the outermost edges of said flexible sheet inwardly,
said springs enabling said transverse ends of said lifter to be
resiliently flexible when said edges engage an object to be
lifted.
7. The vacuum lifter of claim 1 and further including limiting
means provided on at least one of said transverse edges of said
lifter, said limiting means acting to prevent more than a
predetermined spacing between said flexible lifter and said support
means.
Description
This invention relates generally to vacuum lifters and more
particularly to a flexible lifter which is longitudinally stiffened
to enable its use for cylindrical or arcuate objects such as
newsprint rolls.
One of the most difficult handling problems for stevedores in
loading and unloading cargo ships, trailers and other formes of
conveyance are newsprint rolls which are generally in a weight
range of 1,000 pounds to 3,000 pounds and are cylindrically shaped
having a diameter ranging from approximately 36 inches to 44
inches. At present, newsprint rolls are normally loaded and
unloaded by use of fork lift trucks having clamping devices which
embrace the newspaper roll and are then clamped tightly against the
outer surface to frictionally engage the roll while lifting the
roll and moving it from one place to another. In order to
frictionally engage the newsprint roll the clamping surfaces are of
necessity abrasive to permit slippage of the newsprint roll when
the roll is lifted and lowered. The lifting and lowering stresses
as well as the abrasive surface of the lifters often causes damage
to the newsprint roll. In addition, unless the roll is standing on
one of its planar edges, it is difficult for the clamping device to
get underneath the roll in order to embrace and carry the roll.
It is therefore an object of the invention to overcome the
aforementioned disadvantages of the prior lifting devices.
Another object of the invention is to provide a new and improved
lifting attachment for use on fork lifting trucks which will enable
newsprint rolls to be easily handled and which will withstand the
operational shocks and prevent damage to the newsprint rolls.
Yet another object of the invention is to provide a new and
improved lifting attachement for use on fork lift trucks which will
facilitate the handling of newprint rolls whether the newsprint
roll is standing on its planar or cylindrical surface.
Still another object of the invention is to provide a new and
improved flexible lifter which is stiffened longitudinally to
enable securement of the flexible lifter to the object to be lifted
from a lateral disposition.
Still another object of the invention is to provide a new and
improved flexible lifter attachment which can be utilized by fork
lift trucks and other conveyance devices which are secured to an
object from a lateral position.
These an other objects of the invention are achieved by providing a
new and improved vacuum lifter for arcuately shaped objects which
comprises a flexible sheet having opposed parallel surfaces.
The sheet has a supporting member connected to one surface of the
sheet and a resilient gasket connected to the opposing surface of
the sheet about its periphery thereof. A source of vacuum is
provided which is connected through a port in the sheet. A
stiffening means is provided which is connected to the flexible
sheet to prevent bending of the sheet about a line extending at an
angle transverse to the longitudinal extent of the sheet. The
lifter is secured to an arcuate object by placing the gasket
against the outer surface of the object so that a partial vacuum is
formed in the compartment formed between the outer surface of the
object, the sheet and the gasket. The sheet accomodates a range of
diameters of arcuate objects by bending around the longitudinal
axis to conform to the diameter of the object.
Other objects and many of the attendant advantages of this
invention will be readily appreciated as the same becomes better
understood by reference to the following detailed description when
considered in connection with the accompanying drawings
wherein;
FIG. 1 is a front elevational view facing the gasket side of the
vacuum lifter;
FIG. 2 is a top plan view of the lifter;
FIG. 3 is a side elevational view of the lifter;
FIG. 4 is an enlarged sectional view taken along the line 4--4 in
FIG. 1; and
FIG. 5 is an enlarged fragmentary sectional view taken along the
line 5--5 in FIG. 1.
Referring now in greater detail to the various figures of the
drawing wherein like reference numerals refer to like parts, a
flexible vacuum lifter embodying the invention is shown generally
at 20 in FIG. 1.
As seen therein, the flexible lifter 20 basically comprises a
flexible sheet 22 having a pair of opposed parallel surfaces a
sealing gasket 24, a supporting member 26 (FIG. 2) and longitudinal
stiffening means comprising a plurality of narrow longitudinally
extending plates 28 connected to the front surface of sheet 22 and
similar plates 30 connected to the rear surface of the sheet
22.
The sealing gasket 24 is connected about the periphery of the front
surface of the sheet 22 and is preferably comprised of a resilient
deformable closed cell material such as neoprene. The flexible
sheet 22 preferably comprises a thin sheet of polyurethane but may
also be formed of other suitable high tensile strength flexible
materials such as neoprene or metal.
The supporting member 26 as best seen in FIG. 4 basically comprises
a cylindrically arcuate supporting plate 32, a pair of transversely
extending lifting bars 34, which are suitably welded to the
supporting plate 32, and a plurality of integrally formed planar
ribs 36 which extend transversely to the plane of arcuate lifting
plate 32 and lifting bars 34. A supporting bar 38 is interposed
between the supporting plate 32 and the flexible sheet 22. A
similar supporting bar 40 disposed adjacent the front surface of
the flexible sheet aligned with the supporting bar 38 and centrally
of the flexible sheet 22 is also provided. A plurality of suitable
fastening elements 42 extend through the supporting plate 32,
supporting bars 38, sheet 22 and bar 40 to secure a sheet to the
supporting member 26.
As best seen in FIG. 1, the stiffening plates 28 extend
longitudinally of the flexible lifter and are transversely spaced
along the transverse extent of the front surface of the sheet 22.
As best seen in FIG. 2, the longitudinally extending plates 30
extend parallel to and are aligned with corresponding plates 28 on
the opposing surface of sheet 22. The plates 30 also extend
longitudinally and parallel to a supporting bar 38.
As best seen in FIG. 5, each of the plates 28 includes a plurality
of washers 44 which are spaced along the length of the plate 29.
Each of the washers 44 are preferably welded to the plates 28 and
are aligned with an opening through which a suitable threaded
fastener 46 extends. A similar plurality of openings are provided
in plate 30 which are aligned with plates 28 so that fastener 46
can be telescoped through the plate 28, the washer 44, the plate 30
and then suitable secured to a nut 48 on the opposite side of plate
30. The head of the fastener 46 is preferably countersunk so that
the front surfaces of plates 28 are completely flush and do not
provide an abrasive surface which can abut the newsprint rolls.
Referring to FIG. 2, it should be noted that supporting member 26
further includes a bridging plate 47 which is integrally connected
between lifting bars 34 and is integrally welded to a collar 49
which is journalled over a lifting pin 50 of a fork lift truck (not
shown).
The support mechanism for supporting the lifter 20 is shown in
phantom in FIGS. 1 and 2. The supporting mechanism is preferably of
the type that rotates 90.degree. about the horizontal axis
extending longitudinally of the truck and centrally through the
center of the support mechanism. The support mechanism of the truck
may also rotate 360.degree. about the same axis.
As best seen in FIG. 4 a pair of L-shaped brackets 52 are secured
to the rear of the support plate 32 preferably by welding. The
brackets 52 are mounted adjacent a pair of longitudinally extending
slots 54 which extend through the supporting plate 32. Both of the
brackets 52 support a leaf spring 56 which extend through openings
54 and are secured to the brackets 52 by suitable fasteners 58. The
leaf springs 56 act to urge the flexible lifter to its smallest
diameter which is shown in phamtom at 20' in FIG. 2.
Referring to FIG. 4, it can be seen that plates 40, 38 and 32 as
well as the sheet 22 includes an opening through which one leg of
an L-shaped pipe 60 extends. Pipe 60 is connected to a suitable
source of vacuum as indicated by arrow 62 in FIG. 4. The preferred
source of vacuum is reservoir tank which is in turn connected to a
suitable vacuum pump.
The plates 28 which act as stiffening members also act in
combination with washers 44 to distribute the vacuum uniformly
through the entire front surface area of the flexible lifter 20.
That is, the washers 44 space the major portion of plates 28 from
the front surface of sheet 22. Accordingly, as is indicated by
arrows 64 in FIG. 4, air can readily pass beneath the plates 28
past the washers 44 even when the resilient gasket 24 is deformed
so that the plates 28 rest against the outer surface of an object
being lifted.
As best seen in FIG. 4, a suitable cylindrical object such as a
newsprint roll 66 can be secured to the lifter 20 by disposing the
gasket 24 against the outer periphery of the roll 66. Suitable
valves are then opened to connect the port provided in the sheet 22
by pipe 60 to the source of vacuum and thereby cause a reduced
pressure within the compartment formed between the outer surface of
the roll 66, the gasket 24, and the front surface of sheet 22. Once
the gasket 24 has been properly seated, a partial vacuum is formed
very quickly within this compartment and thereby enables the
flexible lifter to be so secured to the roll 66 as to easily enable
the lifting of the newsprint roll 66.
As best seen in FIGS. 3 and 4, a limiting member 68 is provided on
the leftmost (as seen in FIG. 4) stiffening plate 30 of the
flexible lifter. The limiting member 68 basically comprises a pin
70 having a pair of transversely extending end pins 72 and 74 which
are integrally secured at the ends of pin 70. Pin 70 is connected
centrally of the end pins 72 and 74.
The end pin 74 is suitably journalled in a pair of annular collars
76 which are preferably welded to plate 30. Pin 70 extends through
a slot 78 in the plate 32. The pin 70 is thus pivotable around an
axis through pin 74 which is journalled in collars 76. The maximum
separation of the plate 30 from plate 32 is limited by pin 72 which
abuts the rear surface of plate 32 when plate 30 is moved with the
flexible lifter 20 to the position shown in phantom at 20' in FIG.
2. The limiting member 68 is provided so that the flexible lifter
20 may be used not only as shown in FIGS. 1 through 5 where the
longitudinal plates 28 and 30 extend vertically but also when the
lift truck rotates the flexible lifter to a position where the
longitudinal plates 28 and 30 extend horizontally.
When the plates 28 and 30 extend horizontally, the limiting member
68 is at the uppermost end of the flexible lifter and prevents the
weight of plates 28 and 30 from causing the upper portion of the
flexible sheet to be bent to a diameter which is too small to fit
over a cylindrical object. That is, the weight of the plates could
cause the flexible sheet to curl over which prevents the gasket
from being properly seated without the limiting member 68.
As best seen in FIG. 1, the sealing gasket 24 has four enlarged
portions 80, 82, 84 and 86. The portions 80, 82, 84 and 86 which
extend outwardly of the periphery of the remaining portion of the
gasket 24 are not adhesively secured to the front surface of the
sheet 22 as is the remaining portion of the gasket. The enlarged
portions 80, 82, 84 and 86 are provided where the vacuum lifter 20
can be rotated 360.degree. about an axis extending horizontally and
transversely to the center plate 40. In most lift trucks where
there is only 90.degree. of rotation, only two enlarged portions of
the gasket need be provided. For example, in FIG. 1 only portions
84 and 86 would be required since these would be the portions of
the gasket which are in the uppermost position when the flexible
lifter is seated against the outer surface of an object to be
lifted.
The enlarged portions of the gasket are therefore provided because
as the arcuate object is picked up off the ground, the maximum
unseating stress comes at the uppermost portion of the gasket and
the extra portion of the gasket acts to prevent the unseating at
its most vulnerable spot.
It can therefore be seen that a new and improved flexible lifter
has been provided for lifting arcuate objects. The stiffening
members comprised of plates 28 and 30 act to enable the flexible
sheet 22 to be arcuately bent only about a longitudinally extending
line. Similarly, the stiffening members prevent the bending of the
flexible sheet about a line transverse to the longitudinal extent
of the lifter.
In operation the flexible lifter 20 is used in combination with a
truck having a supporting system which is capable of raising and
lowering as well as rotating the flexible lifter 20. In its typical
utilization the flexible lifter is urged laterally towards an
object which is to be lifted and as soon as the gasket is
substantially seated the source of vacuum is connected to the
vacuum compartment formed between the gasket and the flexible sheet
22. As soon as the gasket is seated, the compartment is closed by
the outermost surface of the object.
As set forth above, a newspaper roll may be attached to the
flexible lifter when the roll is either in a vertical or horizontal
position. When the roll is in a vertical position the flexible
lifter is laterally moved to substantially the center of the roll
and laterally engages the roll as set forth above.
Similarly, when the roll is on its side, the lifter 20 is rotated
to a position 90.degree. from the position shown in FIG. 1 and is
lowered so that the lifter plate 40 is substantially aligned with
the center of the roll. The lifter 20 is moved laterally towards
the roll and as soon as the gasket is substantially aligned with
the roll the source of vacuum is connected to the compartment
formed between the gasket 24, the outer surface of the roll and the
front surface of sheet 22. As soon as the partial vacuum is formed
in this compartment, the newspaper roll can be lifted and
transported as desired. To remove the roll from the lifter, a
suitable valve is opened to restore atmosphere pressure to the
lifter compartment.
Without further elaboration, the foregoing will so fully illustrate
my invention that others may, by applying current or future
knowledge, readily adapt the same for use under various conditions
of service.
* * * * *