Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
10~54
This invention relates to vacuum lifting apparatus
for heavy cylindrical articles such as rolls of newsprint
paper or kraft paper, wrapped or not wrapped, one or several
rolls in one wrapper, in good as well as in damaged condition,
these rolls being gripped at the cylindrical surfaces
thereof. For the sake of convenience, this apparatus is
described herein in connection with rolls of newprint paper.
There are many suction pick-up devices in the
prior art, but most of these do not appear to have been very
successful when applied to a wide range of diameters.
Mechanical clamping devices are still most widely used
despite the fact that they have distinct disadvantages in
their inability to handle rolls in tightly placed situations
and often damage the rolls.
A typical suction pick-up device in common use is
mounted on the forward portion of a lift truck so that i~t
can be raised and lowered by the hydraulic system of the
truck. It includes a large suction cup which is pushed
against the side of the ~oll of paper and then vacuum is
applied to suck the roll against the cup so that the roll
can be lifted for transportation. However, the sealing
means of the vacuum cup is such that it will not easily
comply with a large range of roll diameters, limiting its
usefulness. The poorer compliance of the sealing component
also increases the level of skill required by the operator
thereby adding to the difficulty of having well trained
operators available for ship loading or discharge operations.
The vacuum lifting apparatus of the present
invention is designed to eliminate or greatly reduce these
problems. This apparatus can pick up two rolls, but it also
la~ls~4
can pick up or drop one roll at a time. Obviously, the
apparatus could be constructed to handle only one roll at a
time.
In the preferred form, the present apparatus
includes at least two pairs of suction pads or cups. Each
pad can swing horizontally and vertically, each pair of pads
can swing as a unit horizontally, and the carrier on which
the four pads are mounted can swing horizontally. These
self-aligning features and the design features of the seals
used with these pads reduce the accuracy and skill required
by the driver of the lift truck in order to pick up one or
two rolls.
Each suction pad includes a rigid backing plate
and a pneumatic seal which, combined with the self-aligning
feature of the pad, make it possible to pick up rolls of a
diameter range of from about 30 to 50 inches, or other
equivalent ranges, which is a much larger range than is
possible with existing designs. Specially designed friction
plates within an annular seal of each suction pad form an
important feature of this invention.
Another important feature of this vacuum lifting
apparatus is that when two rolls are lifted, they are swung
- and wedged together so that they do not swing apart when the
vehicle turns corners. This increases safety of operation
and keeps rolls close together for neat placement at destination.
The present apparatus is very easy to maintain,
and a suction pad can be replaced in a few minutes. The
entire lifting apparatus is designed as compact as possible
to maintain best visibility for the driver so that he can
see the rolls clearly when he approaches them for pick up,
:,.,:,
~0~954
at any height or when he is trying to place rolls at their
destination.
Vacuum lifting apparatus in accordance with this
invention comprises a support, and a first main lifting
S unit mounted on the support for limited swinging movement;
said main lifting unit compri~ing a ~acking plate hav~ng a~
inner surface in cross section in a generally shallow curve
from one edge to an opposite edge of the plate in order to
extend over the curved surface of a cylindrical article,
a seal on the inner surface of the backing plate in the form
of a continuous pneumatic tube with side sections extending
along the plate near said opposite edges and spaced apart
end sections extending between adjacent ends of said side
sections, said seal projecting outwardly from the inner
surface of the backing plate to form a cushion for a cylindrical
article and a seal against said article and forming a suc-
tion space over said inner surface, means for retaining the
seal on the backing plate, means at the backing plate
through which suction can be applied to said suction space, ~ .
and a pair of spaced-apart vertical friction plates mounted
on the backing plate and each located near a side section of
.the pneumatic tube, each of said friction plates having a
horizontally convexed outer surface to be engaged by the
surface of a cylindrical article bearing against said tube,
whereby when the backing plate of the lifting unit is moved
to press the seal against the cylindrical article said
suction.retains the article against the friction plates and
the seal, said swinging movement of the plate ensuring
contact of the entire pneumatic tube with the cylindrical
3~ article and said tube ensuring good sealing contact with
articles of different diameters.
.
If the apparatus is to be used for lifting cylindrical
rolls of many different heightsr it may have a second backing
plate above the first backing plate and having the same seal
arrangement as the latter.
A preferred form of vacuum lifting apparatus in
accordance with this invention is illustrated in the accomp-
anying drawings, in which
Figure 1 is a reduced diagrammatic side elevation
of a lift truck with the vacuum apparatus mounted thereon,
Figure 2 is a diagrammatic front elevation of the
apparatus of Figure 1,
Figure 3 is an enlarged plan view of the vacuum
lifting apparatus,
Figure 4 is a side elevation of the apparatus, but
with the near suction pad removed,
Figure 5 is another side elevation of the lifting
apparatus, showing the back of a suction pad,
Figure 6 is a front elevation of the lifting
apparatus with its left hand pair of suction pads and their
support removed, and the right hand pair of suction pads
removed but showing the support thereof,
Figure 7 is an enlarged front elevation of a
suction pad arrangement including lower and upper suction
pads,
Figure 8 is a back view of the pad arrangement of
Figure 7,
. Figure 9 is an enlarged horizontal section taken
on the line 9-9 of Figure 7,
Figure 10 is an enlarged fragmentary vertical
section taken on the line 10-10 of Figure 9,
-- 4 --
.:: .-: . : , ~, - :
-~, -: .: . , - :
10~19~4
Figures 11 and 12 are diagrammatic horizontal
sections through a suction pad illustrating the contacts
with the seals thereof made with two rolls of different
diameters,
Figure 13 is an enlarged fragmentary perspective
view of the pivotal mounting arrangement of a suction pad,
Figure 14 is a fragmentary section on line 14-
14 of Figure 13,
Figure 15 is an enlarged elevation of the cam
arrangement for a suction pad support, and
Figure 16 is a fragmentary horizontal section
taken on the line 16-16 of Figure 15.
Referring to Figures 1 and 2 of the drawings, 10
is a standard lift truck having the usual vertical tower 11
at its front upon which a carriage 12 is mounted for vertical
movement. The lift truck has the usual hydraulic system for
raising and lowering the carriage~ Vacuum lifting apparatus
15 in accordance with this invention is mounted on carriage
12 so as to be raised and lowered thereby. This apparatus
is designed to lift one or two heavy cylindrical articles,
such as rolls of newsprint paper, for transportation. ,
The vacuum lifting apparatus 15 includes a bracket
20 fixedly secured to carriage 12, and having upper and
lower lugs 21 and 22 projecting outwardly therefrom. A
carrier 25 i9 swingably connected to bracket 20 by a vertical
pin or shaft 26 which has its end supported in lugs 21 and
22. Carrier 25 includes upper and lower yokes 28 and 29
projecting forwardly therefrom through which pin or shaft 26
extends.
A pair of symmetrical supports 33 are mounted on
- 5 -
:. ,. ~ : : ;.
,, . . . - . ..
~041954
and between the upper and lower yokes 28 and 29 o~ carrier
25 at ends thereof, see Figure 3. As supports 33 and the
elements associated with the~ are substantially identical
with each other, only one will now be referred to for the
sake of convenience.
The support 33 include~ forwardly curved and
spaced vertical front and rear walls 36 and 37 joined to-
gether by upper and lower arms 38 and 39. Arms 38 and 39
are journalled to the adjacent ends of the carrier yokes 28
and 29 by a vertical pin or shaft 40. Lugs 42 and 43
project outwardly from opposite ends of upper support arm
38, another pair of lugs 45 and 46 are mounted on front wall
36 spaced below and in line with upper lugs 42 and 43 res-
pectively.
A pair of identical main suction pads or lifting
units 50 and 51 are mounted on the outer ends of the arms of
each support 33. If desired, another pair of identica~ upper
pads or lifting units 52 and 53 may be mounted above the
lower pads 50 and 51, respectively. Pads S2 and 53 are the
same as pads 50 and 51 excepting that they are shorter in
the vertical direction. As these suction pads or lifting units
are basically identical, only one will now be described in
detail, namely pad 51.
Pad 51 has a pair of spaced lugs 55 projecting from
its outer or back surface near the upper edge of the pad as
shown in Figure 8. A horizontal pin 58 journals a block 59
to lugs 55 for vertical swinging movement, see Figures 3,
~ 4 and 13, said block being journalled by vertical pin 60
! to support lugs 43 and 46 of support 33 for horizontal swing-
ing mo~ement. With this arrangement, the suction pad 51
can swing both vertically and horizontally. A stop 64 on
.
`
- 6 -
:
... _ . . . ....
- :- . ~ . :
.. - - . : :
~()419~
the back of pad 51 is aligned with lower arm 39 of support
33 to limit the inward movement of the lower portion of the
suction pad.
Suitable means is provided for resiliently urging
the lower edge 65 of pad 51 forwardly or outwardly relative
to itq !3upport 33, Figure~ 13 and 14 illu~trate one way o:e
accomplishing this. Block 59 has a bore 66 therethrough
below pin 58 and extending at right angles thereto. A
spring 69 is connected at one end to plug 68 which is
threaded in the outer end of bore 66, the opposite end of said
spring projecting from the inner end of the bore and bearing
against the back of pad 51. This spring applies sufficient
pressure to urge the lower end of the pad outwardly.
The details of the construction of suction pad 51
are illustrated in Figure 7 to 10. This pad is made up of a
backing plate 75 having a shallow generally curved cross
section, see Figure 9. A sealing arrangement 76 is located
on the inner surface 77 of plate 75, and includes an annular
seal 78 of generally rectangular configuration mounted on
said inner surface. This seal preferably includes a con-
tinuous pneumatic tube 82 which projects outwardly from the
'backing plate. The seal also includes an anchoring sheet 83
of suitable flexible material, such as rubber, plastics or
the like. This sheet retains the pneumatic tube in proper
position on the backing plate. Tube 82 has vertical side
sections 8g and 85 extending along plate 75 near the side
edges thereof, and spaced-apart horizontal end sections 87
and 88 extending between and connected to adjacent ends of
the side sections. Tube 82 projects outwardly from the
inner surface of bac~ing plate 75 and forms a suction space`
'
, : ; . , : ~, ~ . .
.. . . : .:
lU'~9~4
92 enclosed by said tube.
Spaced vertical and rigid friction strips 95 and
96 are placed over anchoring sheet 83 within suction space
92 and are secured to backing plate 75 by a plurality of
socket screws 98. Upper and lower securing strips 101 and
102 are placed over this sheet within the suction space and
are secured to the backing plate by a plurality of socket
screws 104. These friction strips and securing strips
retain anchor sheet 83 in position on backing pl'ate 75, and
the central portion 106 of the sheet lies loosely against
the backing plate. It will be noted that the outer edges of
strips 95, 96, 101 and 102 are shaped so that they fit
within tube 82. In this form of the invention, tube 82 is
inflated and is fitted around these friction and securing
strips. The edge portion 108 of sheet 83 overlies tube 82
and is drawn around the adjacent edges of backing plate 75
and fitted onto studs 110 projecting from the outer or back
surface of the plate. It will be noted that the edge
portion of the sheet is drawn over the entire edge of the
backing plate all the way around tube 82.
As friction plates 95 and 96 are identical, only
'one, namely plate 95, will now be described in detail.
Friction plate 95 has an outer surface 115 which
is convex in cross section, as clearly shown in Figures 9,
11 and 12. This convex surface has a plurality of horizontal
grooves 117 therein forming horizontal teeth 118, see Figure
10. Each tooth 118 is preferably formed with an upwardly
facing flat surface 120 and a downwardly inclined lower
surface 121 forming therebetween an edge 122. The cross
sectional shape of these teeth is such that they will resist
-, . - ~, , ' . - -: .
10~ 4
downward movement of an object being held against the outer
surface 115.
In the construction just described, tube 82 is
free of anchor sheet 83 but is held in place by the latter.
On the other hand, the tube can be adhesively secured to the
anchor sheet, or the anchor sheet can be molded with the
tube incorporated therein a~d forming a part thereof.
A pipe elbow 130 communicates with an oriface 131
through backing plate 75 which in turn is substantially
aligned with a hole 132 in the central portion 106 of sheet
83 and opening into suction space 92. This central portion
of the sheet is provided with a plurality of relatively
small holes 133 therein.
The elbow 130 is connected to a flexible hose 135,
see Figure 1, which extends to a suction pump, not shown,
mounted on lift truck 10.
As stated above, the lower edge 65 of suction pad
51 is resiliently urged forwardly by spring 66 in block 59.
It is desirable to provide feelers projecting forwardly from
this lower edge to engage the surfaces of rolls to be picked
up to align the suction pads with these surfaces. In this
`example, a pair of feelers or fingers 135 and 136 are
located at opposite ends of the lower edge 65 and project
forwardly from the pad, see Figures 5 and 7 to 9. These
fingers are resiliently biased into their forward position.
In this example, fingers 135 and 136 are formed on the ends
of a piece of wire 137 which is bent in behind the lower
portion of backing plate 75 and is secured midway between
its ends to the plate by screws 138. Actually, wire 137
which is secured at its mid point to the backing plate has
'~ .
_ g _ :
. . . .. .. - . -. - :
.. . . ~ . , ~ . .
,:,
~04~9~4
laterally-extending arms 140 and 141 which are free of and
extend along the back surface of plate 75 and beyond the
ends of lower edge 65 of said plate. Fingers 135 and 136
are formed on the free ends of arms 140 and 141 so that when
suction pad 51 is moved towards a roll, fingers 135 and 136
engage the transversely curved surface of the roll at two
spaced-apart points to align the suction pad properly with
the roll. Continued forward movement of the suction pad
causes fingers 135 and 136 to be depressed until the lower
portion of seal 78 engages the roll surface, following which
the lower edge of the suction pad swings rearwardly until
the entire seal engages the roll surface.
Suction pads 51 can be used alone, but it is
preferable to provide an upper suction pad 53 above each pad
51. The upper pad and its sealing arrangement are the same
as pad 51 and its sealing arrangement 76, with the exception
that pad 53 is not as-long vertically as pad 51. By referring
to Figure 8 it will be seen that lugs 55 are relatively long
and project upwardly above the upper edge of backing plate
75. These lugs are secured to the back of backing plate 144
of pad 53. These lugs are made large and strong enough to
act as strongbacks rigidly securing the backing plates 75
and 144 together.
The lower suction pad is used alone for relatively
short rolls, while the upper pad 53 is brought into play
along with the lower pad for longer or higher rolls. The
upper suction pad has it own elbow 145 which is connected by
; a hose 146, see Figure 1, to the suction source on the lift
truck. The suction of the upper pad is controlled indepen-
' 30 dently of that of the lower pad so that either suction pad
'.
-- 10 --
.
.
5i4
can be used alone or they can be used at the same time.
Summing up, the vacuum lifting apparatus 15 is
made up of two pairs of lower suction pads 50 and 51, and
two pairs of upper suction pads 52 and 53 fixedly secured to
pads 50 and 51, respectively. The pads 50, 52 and 51, 53
form two sets of suction pads. Each set of pads is mounted
so tha~ it can swing to a limited degree both vertically and
horizontally independently of the other set of pads. The
suction pads of each pair are mounted side by side on a
support 33 which is mounted for limited horizontal swinging
action. The two supports 33 are mounted on carrier 25
which, in turn, i9 mounted on lugs 21 and 22 of bracket 20
for limited horizontal swinging action. Bracket 20 is
mounted on carriage 12 of lift truck 10 so that apparatus 15
can be raised and lowered by the hydraulic system of the
lift truck.
It is desirable to prevent rolls that are being
transported by apparatus 15 from swinging away from each
other when being conveyed around a corner, and to hold said
rolls together. For this purpose each pair of suction pads
50, 51 is provided with a cam arrangement 150, shown in
Figures 15 and 16.
- First of all the support 33 is mounted for vertical
movement on shaft 40, and is biased upwardly by a spring 154
against the upper yoke 28 of carrier 25.
The rear wall 37 of support 33 has a cam 158
mounted thereon near its lower edge and located outwardly a ;~
little in a lateral direction relative to shaft 40, see
Figure 16. This cam has a curved cam surface 159 facing
generally downwardly as shown in Figure 15. Carrier 25 is
- 11 - ' `
lO~ L
provided with a complementary cam 162 near its lower yoke
29, said cam having a curved cam surface 163 facing generally
upwardly. The cam surface 159 is normally above cam surface
163, and these surfaces are aligned. The curves of cam
S surfaces 159 and 163 are such that when support 33 is moved
downwardly these ~urfaces engage and cause support 33 to
swing inwardly, that is, generally towards the central
vertical shaft 26.
When carrier 25 is raised by carriage 12 while two
rolls are being gripped by the pairs of suction pads, the
weight of the rolls pulls supports 33 downwardly against the
action of springs 154 causing the cams 158 to engage cams
162. The action of the two cams causes supports 33 to swing
inwardly until the two rolls come into engagement. The cams
cause the rolls to be pressed together so that they do not
swing freely during transport and are in close contact when
placed at destination.
Figures 11 and 12 illustrate the purpose of the
transversely curved outer surfaces llS of friction plates 95
and 96. The line 178 in Figure 11 represents the peripheral
curve of a roll of relative large diameter. This surface
,contacts the surfaces of friction plates 95 and 96 in the
areas 180 and 181. The line 184 in Figure 12 represents the
curved peripheral surface of a roll of relatively small
diameter. The surface of this roll contacts the friction
plate surfaces in the areas 186 and 187. Thus, in both
cases, the roll surfaces contact gently curved surfaces of
the friction plates. This prevents either of the roll
surfaces from coming into contact with vertical corners of
the friction plates. As a large portion of the lift applied
- 12 -
~041~S4
to the rolls is provided through the areas of contact of the
friction plates with the roll surfaces, it is important that
no sharp edges, and particularly vertical edges, of any
length come into contact with the roll surfaces.
The curvature of backing plate 75 and the convexity
and thickness of friction plates 95 and 96 are selected to
use the range of compressibility of the seal tube 82 to best
advantage, that is, to accommodate the largest range of roll
diameters. The seal tube must be depressed to a certain
degree to make a good seal, and should not be depressed
beyond a predetermined point. In other words, there is a
range of depressibility in which the seal tube is most
effective. The backing plate curvature and the cross
sectional curvature of the friction plates are such as to
accommodate with effective sealing as many different roll
diameters as possible.
Assuming that lines 178 and 184 represent rolls of
the largest and smallest diameters, respectively, the
general curve of plate 75 and the transverse curv~s and the
thickness of friction plates 95 and 96 are arranged in
the following manner. The distance 190 between maximum
diameter line 178 and the backing plate at the centre of the
latter in Figure 11 is substantially the same as the distance
191 between the minimum diameter line 184 and the backing
plate at sealing tube 82 in Figure 12. Similarly, the
distance 193 between minimum diameter line 184 and the
centre of the backing plate in Figure 12 is substantially
the same as the distance 194 between the maximum diameter
line 178 and the backing plate at the sealing tube in Figure ;
11.
~4~9~j4
The operation of lifting apparatus 15 is quite
simple. When the operator of lift truck 10 wants to pick up
a pair of rolls, he moves the truck towards the rolls with
carriage 12 at a height corresponding with that of the rolls
to be picked up. The feeler fingers 135 and 136 at the
lower edges of suction pads 50 and 51 first come into
contact with the rolls. These fingers properly align the
suction pads with the roll surface, and further movement of
the truck causes the pads to swing around their horizontal
axes until the seals of the pads are pressed against the
roll surfaces, as shown in Figure 3. The suction pads 52
and 53, if present, are moved against the roll surfaces at
the same time. The pivotal mountings of carrier 25, supports
33 and the suction pads enable the latter to readily adjust
to rolls of different diameters and to compensate for any
errors in alignment of the truck with the rolls when driven
up to these rolls. As the seals 78 project forwardly from
their respective backing plates 75, see Figure 9, they first
come into contact with the surface of each roll and are
compressed until the seal contacts the roll along the entire
length of the seal. As these seals are tubes, they compress
readily, and yet will fit into any depression in the roll
surface. The pneumatic tubes are superior to the resilient
elements used for sealing purposes in the prior art. The
latter do not have the compressibility and the surface
fitting properties of the pneumatic tubes. At this time,
the operator causes suction to be applied to the suction
spaces 92 within the pneumatic seals of the suction pads.
Alternatively, detector or sensor means may be provided at
each suction pad to automatically apply the suction when the
roll surace moves into complete contact with the seals
- 14 -
. ~
~ Q ~
surrounding the suction spaces thereof. The fact that the
pads are hingedly suspended about two axes results in an
even application of the sealing tubes to the roll surface.
The lower section of each tube engages the roll first and
then the suction pad swings vertically until the side
sections and upper section of the tube come into contact
with the roll surface. This results in the pneumatic seal
being aligned prior to making firm contact instead of just
being pushed against the roll which produces seal wear and
might result in the tube not being properly placed against
the surface.
Once the suction has been applied, and the vacuum
forces draw the roll against friction plates 95 and 96,
carriage 12 can be raised to lift the roll upwardly. The
swinging action of carrier 25 and of the two supports 33
enable the pairs of pads to be properly placed against their
respective rolls. When the two rolls are gripped, carriage
12 is elevated to lift them off the ground, after which they
may be transported to any desired location. After carriage
12 is lowered to deposit the rolls the suction is cut off,
and both rolls are free. If it is desired to lift or
discharge one roll only, the vacuum is applied or removed
selectively by means of the operator's controls.
When carriage 12 is raised with rolls gripped by
apparatus 15, the weight of each roll overcomes the upward
force of spring 154 and cam arrangement 150 of each support
33 carrying a roll is brought into action to shift the rolls
against each other. This prevents the rolls from swinging
during transportation, particularly when the lift truck
makes a turn, and keeps rolls in close contact for neat
placement at destination.
