Note: Descriptions are shown in the official language in which they were submitted.
107;~56
This in~ention relates to the production of starting sheet assemblies
for use in electrolytic refinement of metal, and more particularly to a method
of and an apparatus for fabricating starting sheet assemblies to be used as
cathodes in electrolytic cells for metal refinement.
As is well known, electrolytic refinement of metal, such as copper,
is carried out by passing electric current through a number of starting sheets
as cathodes and a number of anode sheets, which are alternately disposed in
rows within an electrolytic cell. In order to increase the operating
efficiency of the refining operation in the cell, it is generally desirable
that as many anode and cathode sheets as possible be arranged in the cell.
It is therefore very important that each of the sheets has an exact flatness
to ensure exact parallelism to exist between adjoining sheets. The exact
parallelism is important to prevent short-circuiting between the sheets
thereby to maintain high level of electrolytic refining efficiency.
The starting sheets are thin sheets and usually have a thickness
of about 0.6mm. Therefore, they are subject to bending, warping and buckling
during the course of handling. For this reason, the known bead forming or
embossing operation for imparting a high degree of flatness and stiffness to
the starting sheets is very important. The operation for attaching to the
starting sheet suspension ribbons used to hang the sheet from a su~pension
bar is also very important because if the attaching operation is not performed
properly, the parallelism to be maintained betr~reen adjoining sheets suspended
in the electrolytic cell will be impaired.
Formerly, the operation for attaching the suspension ribbons to the
starting sheets and for passing the suspension bars through the loops of the
suspension ribbons was carried out manually. This manual operation often
resulted in irregularities and low accuracy in the shape and dimensions of
the starting sheet assemblies made up of the starting sheet, suspeosion bar
and suspension ribbons. It also resulted in high cost of fabrication.
1q)73~il56
Automatic systems for continuously carrying out the embossing and
ribbon attaching operations have recently been developed to fabricate the
starting sheet assemblies automatically.
One example of the known systems is shown and described in Canadian
Patent Number 704,009, issued on February 16, 1965. According to this system,
suspension ribbon blanks are placed vertically across the path of feed of the
suspension bar, and as the suspension bar is moved forward against the ver-
tically placed ribbon blanks, they are bent into U-shape so as to embrace the
suspension bar. The thus bent ribbon blanks are thereafter applied to the
starting sheet to be attached thereto. In this known system, the ribbon blank
bending and attaching operations are carried out while the ribbon blanks,
starting sheet and suspension bar are all moving. Accordingly, it is difficult
to obtain a high accuracy in the operations, the accuracy being affected by
the sheet thickness and hardness of the ribbon blanks as well as the moving
speed and vibrations caused by the movement. ~or this reason, the feed rate
of the sheets, ribbon blanks and suspension bar must necessarily be decreased,
with resultant low performance of the system.
Moreover, in the known system, the straightening or embossing
operation for imparting flatness and stiffness to the starting sheets is
carried out in a press provided separately from the ribbon blank bending and
attaching parts of the system. It is apparent that this necessitates addi-
tional operational steps and that when the press operation is carried out
before the ribbon blank bending and attaching operations, the once straight-
ened or embossed starting sheets are subjected to the risk of deformation in
the subsequent operations.
A still further difficulty exists in the known system. Since the
vertically placed ribbon blanks are bent merely by means of the advancing
suspension bar, they tend to ~ssume the shape of a loop of relatively large
curvature. This shape causes four-point contact between each ribbon blank
.
-
:~ .. , , :
107;~t~s~ i
and the suspension bar which is of rectangular cross section. This four-
point contact is not desirable because it causes inferior electric connection
and reduces remarkably the efficiency of electrolytic refinement.
It is therefore a primary object of this invention to provide a
method of and an apparatus for fabricating starting sheet assemblies
efficiently without the accompaniment of the above stated difficulties.
Another object of this invention is to enable the ribbon blanks to
be formed or bent accurately so that they fit snugly on the suspension bar.
Still another object of this invention is to enable the bent ribbon
blanks to fit positively on the suspension bar so as to provide face to face
tight contact betueen the bar and the blanks during the course of feeding the
; 10 blanks toward the starting sheet.
A further object of this invention is to enable the ribbon blank
attaching operation and the starting sheet straightening operation to be
carried out simultaneously in the same press~ whereby a compact arrangement
of the apparatus is obtained.
. .
~, A still further obJect of this invention is to speed up the fabrica-
tion of the starting sheet assemblies.
Another object of this invention is to enable the ribbon blank
attaching opera~ion to be carried out while the starting sheet is stationarily
supported in the straightening press, whereby high accuracy of the attaching
work can be obtained.
According to one aspect of this invention, there is provided a meth-
od of fabricating a starting sheet assembly for electrolytic refinement of
metal, the assembly being made up of a starting sheet, a suspension bar, and
suspension ribbons connecting the sheet and the bar, said method comprising
: :
the steps of preparing flat ribbon blanks, pressing each of the blanks into a
ribbon blank bending die to form it into a substantially U-shaped bent ribbon,
transporting the bent ribbon along a path to a ribbon attaching position in
~, . .i ~ . . ........... . . .
. .
10'7;~St;
a press while it is being held in the bending die with the open side of the .. :
bent ribbon directed toward the press while at the same time embracing the
suspension bar placed in said path and pushing the bar toward the press,
supplying the starting sheet into the press, applying the two free ends of
the bent ribbon onto both side faces of the starting sheet in the press at
the end of said path, and operating the press to straighten the starting
sheet and to attach the bent ribbon to the starting sheet.
According to another aspect of this invention, there is provided
an apparatus for fabricating a starting sheet assembly for electrolytic
refinement of metal, the assembly being made up of a starting sheet, a sus-
pension bar, and suspension ribbons connecting the sheet and the bar, said
apparatus comprising press means for straightening the starting sheet and
attaching the suspension ribbons to the same, ribbon bending dies each dis-
posed adjacent to said press means, pusher means for forcing a flat ribbon
blank into each of said dies to form the same into a substantially U-shaped
bent ribbon, and means for moving each of said dies to said press along a
path with the U-shaped bent ribbon held therein and with the open side of the
bent ribbon directed toward ~aid press thereby to ena.ble the suspension bar
placed in said path transversely thereto to be embraced by the bent ribbon as
; 20 it is moved toward the press, whereby the bent ribbon moved to the press is
attached to the starting sheet in the press by the operation of the same
with the suspension bar passed through the bent ribbon.
A preferred embodiment of the invention will now be described by way
of example and with reference to the accompanying drawings in which like parts
are designated by like reference characters and numerals. . .
In the drawings:
Figure 1 is a perspective view showing a typical starting sheet
. assembly which can be fabricated according to this invention;
Figure 2 is a perspective view explanatory of the basic principle
.
10'7;~56
of this invention, showing how flat ribbon blanks are bent and applied to a
starting sheet,
Figure 3 is a side elevation showing schematically a preferred
form of the apparatus for fabricating starting sheet assemblies according to
this invention;
Figures 4, 5, fi and 7 are views similar to Figure 3, but showing
the apparatus in different succeeding stages of operation, and
Figure 8 is a fragmentary vertical section on a much enlarged
scale showing an eyelet punching device used in the apparatus shown in
Figures 3 through 7.
Referring to Figure 1, there is illustrated an example of a starting
sheet assembly which can be fabricated by the method and apparatus according
to this invention. The starting sheet assembly comprises a starting sheet S,
suspension ribbons R of inverted U-shape and a suspension bar B, as is well
known in the art~ Each suspension ribbon R is passed around the bar B and
fixedly secured to the sheet B at 2.
According to this invention, each ribbon R is first prepared in the
form of a flat straight ribbon or ribbon blank Rl as shown in Figure 2, which
is then subjected to a bending operation to be formed into a bent ribbon R2
shown in the same figure. The bend ribbon R2 is then caused to assume the
horizontal position shown in the solid lines and thereafter applied to the
starting sheet S by being moved in the direction of arrow 3, with the bar B
passed through the space formed between two bent arms of each bent ribbon R2.
The starting sheet assembly fabricating apparatus generally desig-
nated by reference character E in Figures 3 through 7 performs the above
stated operation to produce the assembly shown in Figure 1.
~ eferring first to Figure 3, the starting sheet assembly fabri-
cating apparatus E comprises essentially an apparatus section C for shaping
and feeding ribbons and an apparatus section D for straightening starting
... ': ' .
~l~7;~ 6
sheets and attaching the ribbons thereto.
The apparatus section C comprises a pair of ribbon blank storage
boxes 4 disposed adjacent to each other and each adapted to store therein a
stack of ribbon blanks Rl of the shape shown in Figure 2. It is to be under-
stood that only one of the blank storage boxes 4 can be seen in Figure 3.
One of the boxes 4 is adapted to supply the ribbon blank Rl to be attached to
one side of the starting sheet S, and the other box 4 the ribbon blank Rl
to be attached to the other side of the starting sheet S. The boxes 4 are
fixedly mounted on a stationary frame (not shown) of the apparatus.
me apparatus section C further comprises a conveying device 5 for
taking the ribbon blanks Rl out of the boxes 4 and conveying them to a desired
location. The conveying device 5 is made up of stationary rails 5a fixed to
the apparatus frame, a carriage 5b horizontally movable on and along the
rails 5a, vertical pneumatic piston-cylinder devices 5c secured to the carriage
5b, a common support member 5d rigidly secured to the free ends of the piston
rods of the piston-cylinder devices 5c, and vacuum heads 5e. The carriage
5b is driven by a motor, not shown, along the rails 5a and c~n be moved to a
position over the boxes 4. When the pistons in the piston-cylinder devices
5c are moved downward at this position, the vacuum heads 5e are brought into
contact with the upper surfaces of the uppermost ribbon blanks Rl in the boxes
4, and when the pistons are moved upward thereafter, the uppermost ribbon
blanks Rl are lifted by the heads Se. Thereafter, the carriage 5b is moved to
the left as viewed in the figure along the rails 5a. When the pistons are
then moved downward again after the carriage 5b has arrived at the position
shown and the ribbon blanks Rl are released from the heads 5e by cutting off
the vacuum in the heads, the blanks Rl are placed on the desired location for
subse~uen* processing.
The apparatus section C further comprises a ribbon blank mov~ng
device 6, which includes a pair of ribbon blank pushers 12 in the form of
~0~ 56
pneumatic piston-cylinder devices mounted on the apparatus frame. mese
pushers 12 are located below the ribbon blank storage boxes 4, respectively.
Each pusher 12 has a piston (not shown) therein and a piston rod 13 extends
horizontally outward therefrom. The piston rod 13 has a pushing head 14.
The pushers 12 are mounted on a hori ontal table 6a on which the ribbon blanks
Rl released from the vacuum heads 5e are placed. After the ribbon blanks
Rl are put on the table 6a, the rod of the pusher 12 is advanced to the left
in accordance with an operating sequence of the apparatus E so as to move the
blanks Rl on the table 6a to the left to cause the same to be subjected to the
operation of a subsequent ribbon blank bending device 8.
The ribbon blank bending device 8 comprises a pair of pushers 17
in the form of pneumatic cylinders each provided with a ribbon bending head
16 at the leading end of a piston rod 15. Each of these pushers 8 is ver-
tically mounted on the frame (not shown) of the apparatus E. The rods 15 of
the pushers 17 are movable downward in accordance with the operating sequence
of the apparatus E to press each of the ribbon blanks Rl into a ribbon bending
die 7 while pressing the center part of the ribbon blank from above so as to -
bend the blank into a U-shaped ribbon R2 in cooperation with laterally ad-
joining bending rolls 18 and 19.
me apparatus section C further comprises a bent ribbon transport-
ing device 9 including a pair of moving members 21 movably supported through
wheels 21a on horizontally disposed guides 20, which are mounted on the
apparatus frame (not shown~ so as to be located below the aforementioned de-
vices, a rotary member 22 provided with the ribbon forming die 7 and pivotally
mounted at 22a on the foremost end of each moving member 21, and a pneumatic
cylinder 24 secured to each moving member 21 through a bracket 23, the
cylinder 24 having a piston rod 25 with its free end pivotally connected at
22b to the lower end of the rotary member 22.
This device 9 is operated in accordance also with the operating
1073~56
sequence of the apparatus E.
Before the rod 15 of the ribbon blank bending device 8 starts
moving down, the rod 25 of the cylinder 24 extends to rotate the rotary member
22 clockwise, thereby directing the ribbon bending die 7 thereof upwardly
(see Figure 3). The rod lS is then moved down to press the ribbon blank Rl
into the ribbon bending die 7 so as to form the blank into an app~ximately
U-shaped form as shown in Figure 4. Thereafter, when the rod 15 is moved up,
the rod 25 of the cylinder 24 is retracted to rotate the rotary member 22
counterclockwise, with the base end of the ribbon R2, which has already
been formed into the bent form, held within the ribbon bending die 7 as shown
in Figure 5. Then, the moving members 21 are moved forward to the left to
transport the thus bent ribbons R2 to the ribbon attaching position of the
apparatus section D. to cause the ribbons R2 to hold therein suspension bar
B, which is fed in advance in the paths of movement of the ribbons R2, as
shown in Figures S and 6. When the ribbons R2 have been attached to the
starting sheet S in the apparatus section D, the moving members 21 are retracted
to the right for preparation of succeeding bent ribbons R2, as shown in
Figure 7.
Ne~t, description of the apparatus section D for straightening
starting sheets and attaching ribbons thereto will be presented. This section
D comprises a starting sheet straightening part 27 for subjecting the starting ~-
sheets S to an embossing operation and a ribbon attaching part 28, said parts
27 and 28 having a common surface disposed in a single horizontal press plane.
The apparatus section D has a press platen 29 associated with an upper movable
die 38 capable of simultaneously carrying out both the embossing operation
and ribbon attaching press operation, in cooperation with a lower stationary
die 33, in a single press cycle. The press has eyelet hole punching devices
. - .
30 adapted to be actuated~a~t t~ s~a~me as the actuation of the press to
make, in the starting sheet S fed in the press eyelet, holes for attaching the
-- 8 --
107~56
bent ribbons to the sheet S. The eyelet hole punching devices 30 are pro-
vided in the ribbon attaching part 28.
Turning now to Figure 8, each eyelet hole punching device 30 com-
prises a cylinder 31 such as a hydraulic or pneumatic cylinder, a head 35
mounted on the upper end of a piston rod 32 of the cylinder 31 and slidably
received within a guide sleeve 34 secured to the lower surface of the lower
die 33 of the press, a punching pin 35a on the head 35, a hole making die 37
mounted above a through hole 36 for the head 35 formed in the lower die 33,
and an aperture 39 formed in the upper die 38 in opposed relationship to the
hole making die 37.
As most clearly shown in Figure 4, a pair of walking beams 40 are
disposed along the pass line 41 of the press in suitably spaced relation.
These beams 40 are provided to deliver finished starting sheet assemblies
from the apparatus section D in accordance with the operating sequence. On
the opposite side of the apparatus section or press D, conveying means may be
provided to supply the starting sheets S into the press.
me process for the production of the starting sheet assemblies in
accordance with this invention will be described below in the order of steps.
.
A ribbon blank Rl taken out of each ribbon blank storage box 4 by
means of the ribbon blank conveying device 5 is conveyed to be positioned
directly below the ribbon blank bending device 8 by means of the ribbon blank
moving device 6. At this time, the ribbon bending die 7 formed in the rotary
member 22 of the bent ribbon transporting device 9 is directed upward as shown
in Figure 3. Then, the bending head 16 of the ribbon blank bending device 8
is moved down to press the ribbon blank Rl into the ribbon bending die 7,
whereby the flat ribbon blank Rl is formed into the U-shaped bent ribbon R2
as shown in Figure 4. When the rod 15 of the bending device 8 is raised, the
rotary ~ember 22 of the bent ribbon transporting device 9 rotates counter-
olockwise while holding the base end of the bent ribbon R2 within the ribbon
.
~0'~;~8S6
bending die 7, as shown in Figure 5 Then, the moving member 21 is moved for-
ward to the left as shown in Figure 6 to transport the thus bent ribbon R2
to the ribbon attaching position in the apparatus section D, while holding the
suspension bar B, which has been placed in advance in the path of movement of
the ribbon R2, between the two arms of the bent ribbon R2. It is to be
noted that each single pressing operation of the apparatus section D can per-
form both the embossing operation for imparting plane form and stiffness to
the starting sheet S and the ribbon attaching press operation for attaching
the bent ribbons R2 to the starting sheets. After the bent ribbons R2 have
been attached to the starting sheet S, the moving member 21 is returned to its
original position as shown in Figure 7 in preparation for the next cycle. It
will of course be understood that succeeding ribbon blanks Rl to be handled
have already been taken out of the boxes 4 and placed in the position on the
bending rolls 18 and 19 by this time by the operation of the ribbon blank
conveying device 5 and the ribbon blank moving device 6, and that feeding of
a starting sheet into the apparatus section D and delivering of the finished
; starting sheet assembly have also been carried out in accordance with the
operating sequence of the apparatus E.
The operation of the apparatus section D for straightening starting
sheets and attaching ribbons thereto will further be described below.
When the starting sheet S is fed to the desired position between
the upper and lower dies 38 and 33 of the press and the bent ribbons R2 to be
attached to the starting sheet are fed to the desired position, the press is
first actuated, whereby the upper die 38 descends to effect the embossing
operation in order to impart plane form and stiffness to the starting sheet S,
during which operation, pressurized fluid is introduced into the cylinder 31
of the punching device 30 to raise the rod 32. As a consequence~ the punching
pin 35a of the head 35 is passed through the hole making die 37 so as to punch
a hole through the starting sheet S placed thereon as well as through the bent
_ 10 --
107~ S6
ribbon R2, and at the same time, ribbon attaching work is performed. More
specifically, an eyelet-hole burr formed around the punched hole by the
punching pin 35a extended therethrough is pressed downward and deformed by
the upper die 38 to join the ribbon R2 to the sheet S. Thus, both the
straightening operation and the ribbon attaching operation are simultaneously
accomplished in a single press cycle thereby to obtain a f~nished starting
sheet assembly having excellent planar form. It will be understood that the
thus obtained starting sheet assembly can maintain excellent parallelism
with adjoining similar sheet assemblies when suspended in the electrolytic
cell.
In accordance with this invention, each ribbon blank Rl taken out
of the storage box is pressed into the U-shaped bent ribbon R2 outside the
press, and, therefore, the ribbon blank can be processed in a stabilized state
irrespective of blank thickness and hardness, whereby a high level of dimen-
sional and other forming accuracies can be obtained. In addition, the thus
formed bent ribbon can be transported to the ribbon attaching position as it
is without any additional adjusting work, whereby a starting sheet assembly
of high quality can be obtained.
'.
