U.S. patent number 3,850,793 [Application Number 05/344,276] was granted by the patent office on 1974-11-26 for molding machine for producing uniform pulp products.
This patent grant is currently assigned to Center For Management Services And Applied Research, Inc.. Invention is credited to Lloyd H. Hornbostel, Clarence R. Knutsen.
United States Patent |
3,850,793 |
Hornbostel , et al. |
November 26, 1974 |
MOLDING MACHINE FOR PRODUCING UNIFORM PULP PRODUCTS
Abstract
A machine for molding an article such as a dash panel from a
pulp slurry includes a frame which supports a movable stock pan
containing the slurry from which the article is molded. A perforate
mold for forming the article is carried in a plenum mounted
adjacent the end of a hollow arm. A passage through the arm
communicates between a remote vacuum source and the interior of the
plenum, and a valve in the passage may be opened and closed to
control the application of the vacuum to the mold. In use, the
stock pan is lifted from its position beneath the mold to immerse
the latter in the slurry and the valve is opened so the slurry is
sucked through the mold, the pulp fibers in the slurry collecting
on the outer face of the mold. A bleed port in the passage permits
outside air to be drawn into the passage to cushion the application
of the vacuum on the mold so the pulp fibers are collected over a
relatively extended period of time to keep the density of the
article uniform throughout its thickness. Ported plates in the
stock pan streamline the flow of slurry into the stock pan from a
main supply to keep the pulp fibers uniformly distributed
throughout the slurry in the stock pan. After the article has been
molded a sprayer is advanced between the plenum and the stock pan
to spray low pressure water against the edges of the mold and
thereby wash away pulp fiber drippings. Thereafter, the sprayer is
retracted and the arm is swung through an arc to carry the mold
into a position below a press which is lowered and clamped to the
plenum. A bladder carried by the press then is inflated to squeeze
excess water from the article and, by virtue of the shape of the
plenum and the arm, the water flows out of the plenum and through
the arm for re-processing and re-use. Once the excess water is
squeezed from the article, the plenum is indexed into an inverted
position and the article is blown off the mold and onto a conveyor
by forcing pressurized air into the plenum. The arm and plenum then
are moved back to their original positions above the stock pan, and
the sprayer is advanced between the mold and the stock pan to spray
high pressure water back and forth across the outer face of the
mold to wash away any pulp fibers clinging to the mold prior to
immersing the mold in the stock pan to begin the next cycle. In an
alternative embodiment, a similar machine includes two plenums
mounted on arms extending in opposite directions from each other
and each plenum carries a mold so the capacity of the second
machine is double that of the first machine.
Inventors: |
Hornbostel; Lloyd H. (Beloit,
WI), Knutsen; Clarence R. (Beloit, WI) |
Assignee: |
Center For Management Services And
Applied Research, Inc. (Beloit, WI)
|
Family
ID: |
23349819 |
Appl.
No.: |
05/344,276 |
Filed: |
March 23, 1973 |
Current U.S.
Class: |
162/391; 162/393;
162/411; 162/228; 162/410 |
Current CPC
Class: |
D21J
5/00 (20130101) |
Current International
Class: |
D21J
5/00 (20060101); D21j 003/00 () |
Field of
Search: |
;162/387,388,391,393,390,410,411,385,220,228 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lindsay, Jr.; Robert L.
Assistant Examiner: D'Andrea, Jr.; Alfred
Attorney, Agent or Firm: Wolfe, Hubbard, Leydig, Voit &
Osann, Ltd.
Claims
We claim as our invention:
1. A machine for molding an article from a pulp slurry, said
machine including a frame, an arm mounted on said frame, a
perforate mold on said arm for forming said article from the pulp
in the slurry, a vacuum source communicating with said mold through
a passage, a stock pan containing said slurry mounted on said frame
and being movable relative to said mold from a retracted position
to an advanced position to immerse said mold in the slurry whereby
the slurry is drawn from said pan by said vacuum to form said
article on the mold, means for controlling the molding of the
article so that the density of the pulp throughout the thickness of
the article is relatively uniform, said means including a bleed
port opening into said passage and permitting outside air to be
drawn into said passage by said vacuum so the vacuum applied to
said mold builds up gradually, a press mounted on said frame and
adapted to squeeze excess water from the article after the latter
is formed on the mold, means for rotating said arm on said frame to
carry said mold between said stock pan and said press, and means
for ejecting said article from the mold after the excess water is
removed from the article.
2. A machine for molding an article from a pulp slurry, said
machine including a frame, an arm mounted on said frame, a mold
supported adjacent one end of said arm, a vacuum source, a passage
extending between said vacuum source and said mold, a stock pan
containing said slurry, mounted on said frame and having an inlet
to receive said slurry from a supply, means for lifting said stock
pan from a lower position into an upper position to immerse said
mold in the slurry, valve means in said passage movable from a
closed position into an open position so said slurry is drawn from
said stock pan by said vacuum to form said article on said mold, a
plurality of ported plates disposed within said stock pan adjacent
said inlet to streamline the flow of slurry into said pan to keep
the pulp uniformly distributed throughout the slurry, a bleed port
in said passage permitting outside air to be drawn into said
passage by said vacuum so the vacuum applied to said mold builds up
gradually to keep the pulp density relatively uniform throughout
the thickness of the article being formed, means for trimming
excess pulp from the mold after the article is formed on the mold,
a press mounted on said frame, means for rotating said arm on the
frame to move said mold between said press and said stock pan, said
press including a head, a clamp connectable between said head and
said mold to hold the mold and head together, a bladder mounted on
said head and adapted to be inflated to squeeze excess water from
said article, an air pressure source, a normally blocked pressure
line communicating between said pressure source and said mold, and
means for unblocking said line after squeezing excess water from
the mold so air from said pressure source blows said article off
the mold, said trimming means including a shower tray mounted on
said frame and adapted to move from a first position adjacent one
side of said stock pan into a second position above the retracted
position of said stock pan when said mold is positioned above the
pan, and a plurality of nozzles carried by said tray and adapted to
spray water on the mold to cleanse the latter of pulp adhering to
the mold after said article is blown from the mold and prior to
molding another article.
3. A machine for molding an article from a pulp slurry, said
machine including a frame, a movable arm mounted on said frame, a
perforate mold carried by said arm to form said article from the
pulp in the slurry, a vacuum source communicating with said mold
through a passage in said arm, a stock pan mounted on said frame
and including an immersion tank having an open upper end and a
lower inlet through which said slurry flows into said tank from a
supply, said stock pan being movable relative to said mold to
immerse the latter in the slurry contained in said tank whereby
slurry is drawn from said tank by the vacuum to form said article
on said mold, means for keeping the pulp uniformly distributed
throughout the slurry in said immersion tank, a bleed port in said
arm opening into said passage to permit outside air to be drawn
into said passage by the vacuum so the vacuum applied to said mold
builds up gradually to keep the pulp density relatively uniform
throughout the thickness of the article being formed, a press
mounted on said frame, means for rotating said arm on said frame to
move said mold between said press and said stock pan, said press
being engageable with said article to squeeze excess water from the
article, and means for ejecting the article from the mold after the
excess water is removed.
4. A machine as defined by claim 3 including means for indexing
said mold relative to said arm between selected positions for
molding and ejecting.
5. A machine as defined by claim 4 including a plenum mounted on
said arm adjacent one end thereof, said mold being mounted on said
plenum, and a tube within said plenum coacting with the outside air
to siphon water from the plenum and into said passage as said
article is formed on the mold.
6. A machine as defined by claim 5 wherein said pulp distribution
means includes a plurality of plates mounted within said immersion
tank adjacent said inlet and having a series of holes for
streamlining the flow of slurry into said tank.
7. A machine as defined by claim 6 wherein said plenum includes
opposite side walls, front and rear walls, an upper wall, and a
lower wall opposite said upper wall and having an opening therein,
said mold being secured to said lower wall within said opening.
8. A machine as defined by claim 7 wherein said upper wall tapers
toward said lower wall upon progressing from the rear wall toward
said front wall so that, as said arm is rotated to move the mold to
said press, said lower wall is moved into an upwardly facing
position and said upper wall is moved into a downwardly facing
position slanted relative to horizontal whereby the water squeezed
from said article by said press flows by gravity out of said plenum
and into said passage to keep said article from being rewetted
after pressing.
9. A machine as defined by claim 7 wherein said bleed port is
located in said arm adjacent said plenum and further including a
valve for selectively opening and closing said port.
10. A machine as defined by claim 9 including a removable cap
having a central opening of predetermined size, said cap being
positioned on said arm to restrict the flow of air through said
port and into said passage.
11. A machine as defined by claim 10 including a valve in said
passage between said plenum and said vacuum source and movable
between open and closed positions to connect and disconnect the
interior of the plenum with the vacuum source, a regulator in said
passage between said plenum and said latter valve for selectively
controlling the level of the vacuum applied to the interior of the
plenum through said passage.
12. A machine as defined by claim 11 including an opening in one
wall of said plenum, a corresponding hole in said arm and aligned
with the opening in said plenum so the passage communicates with
the interior of said plenum, and a seal around said opening between
said arm and said one wall.
13. A machine as defined by claim 7 including two of said arms
spaced from and extending parallel with each other, a support pipe
connected between the ends of said arms opposite said plenum, the
interior of said pipe communicating with the interior of each of
said arms to define a portion of said passage, pins projecting from
each side wall of the plenum and connecting with said arms to mount
said plenum between said arms for indexing relative thereto between
said selected positions for molding and ejecting.
14. A machine as defined by claim 13 wherein each of said arms
includes spaced, parallel side walls and top and bottom walls
tapering toward each other upon progressing from adjacent said
plenum toward said pipe to facilitate the flow of excess water
squeezed from said article through said arms and into said
pipe.
15. A machine as defined by claim 13 wherein said arm rotating
means includes a motor mounted on said frame adjacent said pipe,
gear means connected between said motor and said pipe, said motor
being selectively operable to rotate said pipe about a
substantially horizontal axis to rotate said arms from said stock
pan to said press.
16. A machine as defined by claim 15 including a counterweight
mounted on said pipe opposite said arms and extending away from
said pipe.
17. A machine as defined by claim 15 including a second set of arms
mounted on said pipe opposite said first arms, said second set
extending away from said pipe and supporting a second plenum and
mold for forming said articles.
18. A machine as defined by claim 13 wherein said stock pan
includes an outer tank having a lower outlet for returning slurry
to said supply, said immersion tank fitting within said outer tank,
a return passage defined by the space between said outer tank and
the immersion tank and communicating between the top edge of said
immersion tank and said outlet to guide overflow slurry from the
immersion tank to said outlet.
19. A machine as defined by claim 18 wherein said immersion tank
includes a lower chamber having an upper opening and a lower inlet
communicating with the supply of slurry, an upper chamber for
receiving the slurry from said lower chamber and maintaining said
slurry at a predetermined level in said immersion tank, said plates
being removably secured to said immersion tank across the upper
opening of said lower chamber.
20. A machine as defined by claim 19 wherein said lower chamber
further includes a lower outlet opposite said inlet and having a
bottom slanting downwardly from said outlet toward said inlet
whereby the cross-sectional area of said chamber becomes smaller
upon progressing toward said outlet from the inlet to help maintain
relatively even pressure in the slurry flowing through all of said
plates.
21. A machine as defined by claim 18 including fluid-actuated means
for moving said stock pan between a retracted position and an
advanced position to immerse the mold in the slurry.
22. A machine as defined by claim 20 including a sprayer adapted to
cleanse the edges of said mold of pulp drippings prior to squeezing
excess water from said article.
23. A machine as defined by claim 22 wherein said sprayer includes
a shower tray mounted on said frame to move from a first position
adjacent one side of said stock pan into a second position above
the retracted position of said stock pan, a plurality of pipes
carried by said tray and having upwardly facing small openings for
spraying water on the edges of said mold.
24. A machine as defined by claim 5 including an air pressure
source, a normally blocked pressure line communicating between said
pressure source and said plenum, and means for indexing said plenum
on said arm from said molding position into said ejecting position
to unblock said line and to seal said plenum from the outside air
whereby said pressurized air fills said plenum to blow said article
off the mold.
25. A machine as defined by claim 22 wherein said sprayer further
is adapted to cleanse said mold of pulp adhering thereto after the
article is ejected from the mold and prior to molding the next
article.
26. A machine as defined by claim 25 wherein said sprayer includes
a shower tray mounted on said frame to move from a first position
adjacent one side of said stock pan into a second position above
the retracted position on said stock pan, and a plurality of
nozzles carried by said tray and adapted to spray water on the
mold.
27. A machine as defined by claim 25 wherein said sprayer further
includes a manifold mounted on one end of said tray and having an
inlet opening communicating with a high pressure water source and a
plurality of outlet openings, said nozzles extending outwardly of
said manifold from said openings and each nozzle being pivotally
supported at opposite ends thereof within said tray and having a
plurality of orifices for spraying water onto said mold, and means
for turning said nozzles about their longitudinal axes to spray
back and forth across the surface of said mold.
28. A machine for molding an article from a pulp slurry, said
machine including a frame, an arm mounted on said frame, a
perforate mold on said arm for forming said article from the pulp
in the slurry, a vacuum source communicating with said mold through
a passage, a stock pan containing said slurry mounted on said frame
and being movable relative to said mold from a retracted position
to an advanced position to immerse said mold in the slurry whereby
the slurry is drawn from said pan by said vacuum to form said
article on the mold, means for controlling the molding of the
article so that the density of the pulp throughout the thickness of
the article is relatively uniform, a press mounted on said frame
and adapted to squeeze excess water from the article after the
latter is formed on the mold, means for rotating said arm on said
frame to carry said mold between said stock pan and said press,
means for ejecting said article from the mold after the excess
water is removed from the article, and indexing means for turning
said mold relative to said arm between selected positions for
molding and ejecting.
29. A machine for molding an article from a pulp slurry, said
machine comprising a frame, an arm pivotally mounted on said frame,
a perforate mold pivotally mounted on said arm, a supply of slurry,
means for immersing said mold in said supply, means for sucking the
slurry from said supply and onto and through the immersed mold to
form the article thereon, means for pivoting said arm on said frame
after formation of said article on said mold, a press for
thereafter engaging said article to squeeze excess water therefrom,
indexing means for thereafter pivoting said mold relative to said
arm to turn said mold to an ejecting position, and means for
ejecting the article from said mold when the latter is in said
ejecting position.
30. A machine as defined in claim 29 further including a second arm
pivotally mounted on said frame and projecting oppositely from said
first arm, means connecting said arms for turning in unison, a
second mold pivotally mounted on said second arm, and means for
pivoting said second mold relative to said second arm.
31. A machine as defined in claim 30 in which said arms are mounted
on said frame to turn about a generally horizontal axis and are
free to turn through a complete circle, said supply of slurry being
located at the bottom of said circle and said press being located
at the top of said circle.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a machine for molding an article
from a pulp slurry and, more particularly, to the type of machine
in which a vacuum is used to form the article by drawing the slurry
through a perforate mold. As the slurry is drawn through the mold,
the pulp collects on the outer face of the mold to form the
article. Once the pump reaches a predetermined thickness, excess
water is pressed from the article and the latter is ejected from
the mold for further processing.
SUMMARY OF THE INVENTION
One primary object of the present invention is to provide a new and
improved molding machine of the foregoing character which is
adapted to form the article in a novel manner so that the article
is formed of a predetermined thickness and with a uniform density
throughout its thickness to keep from forming either an excessively
weak or an excessively strong article. A more detailed object is to
accomplish the foregoing through the use of novel means for
maintaining an even distribution of the pulp in the slurry and
further through the provision of unique means for increasing the
length of time over which the vacuum builds up to draw the slurry
through the mold so that the pulp fibers build up uniformly
throughout the thickness of the article without becoming gradated
by size.
A further object is to provide the machine to operate in a novel
manner to form said articles by swinging the mold between
successive forming and pressing stations and indexing the mold on
its swingable support between its pressing and ejecting positions
so as to orient the mold for ejection of the article from the
mold.
Another object is to provide a unique arrangement for draining
water from the machine during the forming and pressing operations
to avoid possibly rewetting the article after the excess water is
squeezed from the article.
A more detailed object of the present invention is to provide a
unique siphon arrangement for removing the strained slurry or white
water from behind the mold as the slurry is drawn through the mold
during the molding process.
Another more detailed object is to provide a unique plenum which
supports the mold and defines a pressure chamber around the back
side of the mold, the plenum being of a unique shape to drain water
away from the mold during the pressing operation so as to avoid
rewetting of the molded article once the excess water is removed
from the article.
The invention also resides in the provision of a novel stock pan
containing the slurry in which the mold is immersed to a
predetermined level and in the unique construction for moving the
mold away from the stock pan to a position beneath a press for
squeezing excess water from the article. In addition, the invention
resides in the unique manner in which the excess water is squeezed
from the article and drained out of the plenum.
The invention is characterized further by the provision of a unique
sprayer movable between the plenum and the stock pan and adapted
both to wash away pulp fiber drippings from the edge of the mold
and the article after the molding operation and prior to the
pressing operation and to cleanse the mold of pulp fibers adhering
to the outer face thereof after ejection of the article from the
mold.
These and other objects and advantages of the present invention
will become more apparent from the following detailed description
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary front elevational view of a molding machine
embodying the novel features of the present invention.
FIG. 2 is a fragmentary cross-section taken substantially along
line 2--2 of FIG. 1 and having phantom lines which show parts of
the machine moved positions.
FIG. 3 is an enlarged fragmentary cross-section taken substantially
along line 3--3 of FIG. 1.
FIG. 3a is an enlarged fragmentary cross-sectional view taken
through the mold.
FIG. 4 is an enlarged fragmentary view taken substantially along
line 4--4 of FIG. 1.
FIG. 5 is reduced fragmentary cross-section taken substantially
alone line 5--5 of FIG. 3.
FIG. 5a is an enlarged fragmentary view showing parts of the
machine in cross section.
FIG. 6 is a fragmentary cross-section similar to FIG. 2 but showing
parts of the machine in moved positions.
FIG. 7 is an enlarged fragmentary cross-sectional view taken
substantially along line 7--7 of FIG. 6.
FIG. 8 is a fragmentary cross-section taken substantially along
line 8--8 of FIG. 7.
FIG. 9 is a fragmentary cross-section similar to FIG. 6 but showing
parts of the machine in moved positions.
FIG. 10 is a fragmentary front elevational view similar to FIG. 1
but showing parts of the machine in moved positions.
FIG. 11 is an enlarged fragmentary cross-section taken
substantially along line 11--11 of FIG. 10.
FIG. 12 is a fragmentary view taken substantially along line 12--12
of FIG. 10.
FIG. 13 is a fragmentary side elevational view of another
embodiment of a molding machine incorporating the novel features of
the present invention.
FIG. 14 is a fragmentary cross-sectional view taken substantially
along line 14--14 of FIG. 13.
FIG. 15 is an enlarged fragmentary cross-sectional view taken
substantially along line 15--15 of FIG. 14.
FIG. 16 is a fragmentary side elevational view similar to FIG. 13
but showing parts of the machine in moved positions.
FIG. 17 is a fragmentary cross-sectional view taken substantially
along line 17--17 of FIG. 16.
FIG. 18 is an enlarged fragmentary cross-sectional view taken
substantially along line 18--18 of FIG. 17.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in the drawings for purposes of illustration, the present
invention is embodied in a molding machine 20 particularly suitable
for use in molding an article 21 (see FIG. 3) from a pulp slurry
23. It will be appreciated that while the present invention is
illustrated and described for molding a dashboard 21 adapted to
collapse upon impact to protect an occupant of an automobile
against serious injury, other types of articles also may be molded
with this type of machine.
Herein, a perforate mold 24 is used to strain the pulp fibers from
the slurry, the fibers collecting on the outer face 25 of the mold
in the desired shape. While different types of molds may be
employed, the mold in the present instance includes a wire screen
22 (see FIG. 3a) which may be formed from 40 to 60 mesh screen
depending upon the desired characteristics of the article to be
molded. To support the screen in its desired shape, it is backed by
a relatively rigid casting 28 which is formed of aluminum and is
perforated with 1/8 inch diameter holes drilled on 3/8 to 1/2 inch
centers.
The slurry is formed in a conventional manner from waste corrugated
paper clippings stirred in water so as to separate into fibers
about three-fourths inch long. The fibers comprise about one
percent of the slurry and flock together to give the slurry a lump
appearance. Also added to the slurry are a wet strength resin and a
thermo-setting plastic resin (e.g., phenolic resin), both of which
adhere to the fibers and thus are separated from the water with the
fibers during the forming process. The thermo-setting resin melts
upon subjecting the freshly molded dashboard to heat and, when
cooled, the resin hardens to bind the fibers together and rigidify
the dashboard.
Initially, the dashboard 21 is formed by immersing the mold 24 in
the slurry 23 and utilizing a vacuum pump 32 to draw the slurry
into and through the mold. As shown in FIG. 1, slurry from a remote
main supply 42 is collected in a stock pan 26 through a lower inlet
27 (FIG. 2) communicating with the supply through a pipe 29. The
stock pan is mounted on a frame 30 which also supports an arm 31
for carrying the mold above the stock pan. More particularly, the
mold is mounted on a plenum 33 which in turn is mounted adjacent
one end 34 of the arm. A vacuum passage 35 communicates between the
vacuum pump and the mold, the passage extending through the arm and
into the interior of the plenum.
To immerse the mold 24 in the slurry 23 collected in the stock pan
26, the latter is lifted on the frame 30 from a retracted lower
position (see FIG. 1) to an advanced upper position (FIG. 3) by two
fluid-actuated cylinders 36 connected to opposite ends 37 of the
pan by brackets 38 and supporting the pan on the frame. Once the
mold is immersed in the slurry, a main vacuum valve 39 in the
passage 35 is opened so the pump evacuates the plenum 33 and causes
slurry to be sucked through the mold, the fibers in the slurry
collecting on the outer face 25 of the mold to form the dashboard
21. The strained slurry or white water then flows through the
passage 35 toward the pump 32 and into a separator tank 48. The
white water enters the separator tank through an upper inlet 48a
and is collected temporarily in the lower portion of the tank. The
passage 35 communicates with the pump through an air outlet 48b in
the top of the tank so that only the air is drawn to the pump.
Periodically, the white water is drawn from the tank through a
lower outlet 48c and is collected for reprocessing and
recycling.
After the dashboard 21 initially is formed on the mold 24, the
stock pan 26 is lowered and the mold is carried by the arm 31 to a
press 40 (see FIG. 2) adapted to squeeze excess water from the
dashboard while also compressing the latter to its desired final
thickness. Thereafter, the dashboard is ejected from the mold onto
a conveyor 41 and is carried away from the machine 20 to be dried
in an oven (not shown) and hot-pressed to set the plastic resin and
thereby complete the molding process.
When forming an article 21 in the foregoing manner, it is desirable
to control the thickness of the article as the fibers are picked up
on the mold 24 so as to keep the fibers from breaking during
subsequent pressing and thereby avoid forming cracks in the
article. Also, it is desirable to keep the density of the article
relatively uniform throughout the thickness of the article and
thereby distribute the resin evenly throughout the article so that,
during further processing, both the inside and outside portions of
the article will be of equal strength. These features are desirable
particularly when molding articles such as the impact-crushable
dashboards 21 in order to keep each dashboard from being so weak as
to collapse too easily when impacted or so strong as to be likely
to cause injury when impacted by the occupant of an automobile
during a crash.
In accordance with the primary aspect of the present invention, the
molding machine 20 includes unique means for controlling the manner
in which the pulp fibers are collected on the mold 24 so the
article 21 may be formed of a predetermined thickness and of a
relatively uniform density throughout such thickness. This is
accomplished through the novel provision of a bleed port 43 (FIG.
5) within the passage 35 to permit the vacuum pump 32 to draw
outside air into the passage so that the vacuum applied to the mold
increases gradually to a preselected intensity without causing the
larger and smaller pulp fibers to become gradated by size as they
collect on the mold to the predetermined thickness dictated by the
preselected intensity of the vacuum. Also, by virtue of the novel
construction of the stock pan 26, the pulp fibers are distributed
evenly throughout the slurry 23 in the stock pan so as to collect
evenly across the outer surface 25 of the mold. For this latter
purpose, means including a plurality of ported plates 44 (FIGS. 3
and 4) are disposed within the stock pan adjacent the inlet 27 and
streamline the flow of slurry into the stock pan so that the pulp
fibers remain uniformly distributed throughout the slurry in the
stock pan. Thus, by keeping the pulp fibers distributed evenly
throughout the slurry and by gradually increasing the vacuum to the
preselected intensity so the larger and smaller fibers collect
together on the mold without becoming gradated, the article is
formed on the mold to a predetermined thickness and the density of
the article is relatively uniform throughout such thickness.
In the present instance, the plenum 33 is supported between two
arms 31, each of which is secured at one end 45 (FIG. 3) to a
substantially horizontal tubular support 46 and is spaced from the
other arm. Herein, each of the arms is hollow so that it defines
one branch 47 (FIGS. 3 and 5) of the passage 35, the latter
communicating with the interior of the plenum through openings 49
in opposite sides 50 of the plenum. Corresponding holes 51 in the
arms are aligned with the openings in the plenum and relatively
thick sealing rings 53 bolted to the plenum around the openings
engage the arms around the aligned holes to keep the vacuum from
leaking between the arms and the plenum. As shown in FIG. 3, the
interior of the plenum is divided into two chambers 54 by a
partition 55 extending the full length of the interior of the
plenum, and the chambers each communicate with the passage 35
through the openings 49. Herein, there are four of the openings in
the plenum, one opening at each end of each chamber so that there
are two openings in each of the two opposite sides of the plenum.
One mold 24 is mounted in each of the chambers, the two molds each
being bolted to a lower wall 56 of the plenum and extending
parallel with each other within two elongated rectangular openings
57 (FIG. 3) in the lower wall. It will be appreciated that while
two molds are disclosed in the exemplary embodiment for molding the
dashboards 21, virtually any number of molds may be secured to the
plenum for molding articles such as the dashboards.
To control the manner in which the pulp fibers are collected on the
outer faces 25 of the molds 24, two of the bleed ports 43 (FIGS. 1
and 3) are formed in the arms 31 although, if desired, the ports
may be formed in the plenum and open directly into the chambers 54.
Preferably, however, one bleed port is located adjacent the free
end 34 of each arm and communicates with the branch 47 of the
passage 35 in that arm. The bleed ports are opened and closed by
valves 60a controlled by solenoids 60 (FIG. 5a), the valves being
open when vacuum is applied to the molds so as to permit outside
air to be drawn through the ports and into the passage by the
vacuum as the dashboards are being molded. This arrangement, in
effect, cushions the application of the vacuum so that the larger
and smaller pulp fibers collect on the outer face of the mold over
a relatively extended period of time and without being gradated by
size so as to keep the density of the dashboards relatively uniform
throughout their thicknesses and to cause the inside and outside
portions of the dashboards to be of generally the same
strength.
One of the porting arrangements is shown in more detail in FIG. 5a
and includes an upwardly projecting neck 43a integrally formed in
the arm around the port 43. Connected to the neck is a housing 43b
within which is mounted the solenoid 60 and the valve 60a, the
latter normally closing a lower aperture 43c in the housing under
the urging of a spring 60b. Advantageously, a removable cap 62
having a central opening 62a is threaded onto the upper end of the
housing and provides a restriction for the air entering the housing
so as to control the amount of air that can be drawn into the
passage 35 through the port 43. It will be appreciated that by
using caps having different sizes of central openings, the amount
of air entering the passage 35 during molding may be changed to
adjust the length of time it takes for the vacuum to build up to
its preselected intensity. In this way, the machine 20 may be
adjusted to mold articles with different densities and
thicknesses.
Further control of the formation of the dashboards 21 is provided
by a vacuum regulator valve 61 (FIG. 1) which is adjustable
selectively to control the ultimate intensity of the vacuum being
applied to the molds 24. The regulator valve is located within a
pipe 63 between the ports 43 and the separator tank 48. The pipe is
connected to the tubular support 46 by a rotatable joint 68,
defines a portion of the passage 35 and houses the main vacuum
valve. The regulator valve is mounted between the main valve and
the joint and provides a relatively fine control to regulate the
intensity of the vacuum applied to the molds. The intensity of the
vacuum, together with the rate control provided by the bleed ports
43, determines the thicknesses to which the pulp fibers build up on
the outer faces 25 of the molds. This is because for each vacuum
intensity, the fibers collect on the molds until the loss of
pressure through the collected fibers equals the difference between
the vacuum pressure in the plenum chambers 54 and the natural
pressure in the slurry adjacent the outer surfaces of the newly
molded dashboards. Therefore, when the bleed ports are fitted with
caps 62 having one size of opening 62a, the thicknesses of the
dashboards being formed may be increased by increasing the
intensity of the vacuum so more fibers collect on the molds, or the
thicknesses of the dashboards may be decreased by decreasing the
intensity of the vacuum.
To avoid the need of adjusting the regulator valve 61 for each
molding operation, the molds 24 are immersed to and held at a
predetermined depth in the slurry in the stock pan 26 for each
consecutive operation so that the natural pressure in the slurry 23
adjacent the molds will be virtually the same for each immersion.
For this purpose, the stock pan includes an outer tank 64 (FIG. 3)
and an immersion tank 65 having side walls 66 spaced inwardly of
the side walls 67 of the outer tank and of a height less than the
height of the side walls 67 so the upper edges 69 of the side walls
66 serve as weirs to maintain a constant level of slurry within the
stock pan. When the molding machine 20 is in use, the amount of
sluurry flowing from the main supply 42 exceeds the amount required
for molding the dashboards 21, and a portion of the excess slurry
flows over the weirs into a return passage 70 defined by the space
between the side walls 66 and 67 of the two tanks. The return
passage communicates with a lower outlet 71 (FIG. 4) in the outer
tank, and the excess slurry flows through the return passage and
the outlet in a return pipe 73 communicating with the main supply
to return the excess slurry to the main supply. Accordingly, when
the cylinders 36 are actuated to lift the stock pan 26 a
predetermined distance, the molds are immersed in the slurry 23
contained in the immersion tank 65 to a predetermined depth
regardless of the amount of slurry displaced by the molds 24 and
the amount of slurry sucked through the molds by the vacuum.
To control the flow of slurry 23 into the immersion tank 65 so the
pulp fibers remain evenly distributed throughout the slurry, the
immersion tank includes an inlet chamber 74 (see FIG. 3) and an
upper chamber 75. The ported plates 44, there herein being four
such plates, are disposed between the two chambers and have spaced
apertures 72 to streamline the flow of the slurry from the inlet
chamber upwardly into the upper chamber within which the molds are
immersed. The inlet chamber is defined by spaced end walls 76 and
77 (FIG. 5), and the inlet 27 for the stock pan 26 is formed in the
end wall 76 above the outlet 71. An outlet 79 is formed in the
opposite end wall 77 and opens into a pipe 80 which leads to the
main supply 42 of slurry to return a portion of the slurry entering
the inlet chamber to the main supply. In the top of the inlet
chamber is an opening 81 (see FIG. 4) within which the four plates
44 are mounted. Each of the plates is bolted to an angle iron 83
extending around the opening for easy removal and replacement with
different plates with different sizes of apertures so as to provide
a means for controlling the rate at which the slurry flows into the
upper chamber. By virtue of the ported plates, the flow of slurry
into the immersion chamber is streamlined to avoid the formation of
areas in the chamber where pulp fibers may concentrate either to a
greater or lesser degree and possibly cause the formation of
excessively thick or thin spots in the dashboards being molded.
As shown in FIG. 5, a wall 84 defining the bottom of the inlet
chamber 74 is spaced upwardly of a bottom wall 85 of the outer tank
64 and slants upwardly upon progressing from the inlet 27 toward
the outlet 79 of the inlet chamber. Accordingly, the
cross-sectional area of the inlet chamber becomes progressively
smaller toward the outlet and this advantageously keeps the
pressure of the slurry in the inlet chamber relatively even across
all of the plates 44 so that approximately the same amount of
slurry flows upwardly through each of the four plates into the
upper chamber 75.
To avoid an accumulation of white water within the plenum 33 as
slurry from the immersion chamber 75 is sucked through the molds 24
by the vacuum, the white water is siphoned out of the plenum and
into the two branches 47 of the passage 35 to be sucked by the
vacuum through the tubular support pipe 46 and into the separator
tank 48. This is accomplished with four siphon tubes 86 (FIGS. 3
and 5) and by taking advantage of the outside air which is drawn
into the two branches of the passage through the bleed ports 43 to
suck the white water from adjacent the bottom wall 56 of the plenum
and into the two branches of the passage. Two of the siphon tubes
are located within each of the chambers 54, the tubes being
disposed at opposite ends of the chambers and extending upwardly
from open lower ends 87 adjacent the bottom wall to open upper ends
89 extending into the openings 49 in the sides 50 of the plenum.
The outside air flows across the open upper ends of the siphon
tubes thereby creating a pressure differential between the upper
and lower ends of the tubes so the white water is sucked up through
the tubes and into the passage branches. Thus, the plenum is
emptied of white water as an incident to the molding operation, and
the white water is collected for reprocessing and recycling.
Once the dashboards 21 are formed on the molds 24 in the manner
described, the stock pan 26 is lowered to its retracted position by
the cylinders 26, and a sprayer 90 (FIGS. 1 and 10) is advanced
between the molds and the stock pan to wash away any excess pulp
and pulp fiber drippings adhering to the edges of the molds and the
newly formed dashboards. As shown in FIG. 1, the sprayer normally
rests on support members 91 which are secured to the frame 30
adjacent one end 37 of the stock pan and includes a shower tray 93
supported by wheels 94 on tracks 95 extending along the tops of the
support members. Additional tracks 96 extend along the upper edges
of the front and rear walls 67 of the outer tank 64 of the stock
pan and are aligned with the tracks on the support members to
permit the shower tray to be rolled into position beneath the
plenum 33. The shower tray is generally rectangular in shape and
encompasses an area somewhat larger than the area defined by the
lower wall 56 of the plenum. The tray includes opposite end walls
97 and 98, side walls 99 (FIG. 11) and a bottom wall 100. A toothed
rack 101 is secured to the outside surface of the rearward side
wall of the tray along the upper edge thereof and engages a gear
103 fixed on a rotatable shaft 104 projecting forwardly from a
small motor 105 (FIG. 10) mounted on the frame 30 adjacent the
rearward side wall. With this arrangement, the tray may be advanced
beneath the plenum by actuating the motor to rotate the shaft in a
counterclockwise direction (FIG. 10).
To wash away the pulp fiber drippings from the edges of the molds
24, four spaced pipes 106 are mounted within the shower tray 93 and
extend parallel with each other, the opposite ends 107 of the pipes
being supported by the end wall 98 of the tray and a header 92
attached to the wall 97. A low pressure water source (not shown)
communicates through a small hose 109 which connects to one end of
the header and, as water from the source is forced through the
header and into the pipes, small openings 110 along the tops of the
pipes direct the water upwardly to wash the pulp fiber drippings
off the edges of the molds. Advantageously, the water sprayed from
the pipes falls back into the tray and thus is kept from diluting
the slurry 23 in the stock pan 26. As shown in FIG. 10, the bottom
wall 100 of the tray is slanted downwardly from the end wall 98
toward the other end wall 97 so that the water flows out of the
tray through a drain 111 located adjacent the latter wall and is
collected for reprocessing and recirculation.
After the drippings are cleaned from the edges of the molds 24, the
tubular support 46 is rotated on the frame 30 to move the arms 31
through a predetermined arc (herein, about 180.degree.) to carry
the molds away from the stock pan 26 and into predetermined
positions beneath the press 40 (see FIG. 2). Attached to the
support opposite the arms is a generally cylindrical counterweight
113 adapted to offset the weight of the plenum 33 and the molds.
Prior to rotating the arms to carry the molds to the press, the
sprayer 90 is retracted from between the molds and the stock pan
and into its normal rest position on the support members 91 so as
to be out of the way of the counterweight. When positioned beneath
the press, the molds are oriented so their outer faces 25 are
directed upwardly toward the press (see FIG. 6) as is the wall 56
of the plenum which, in this position, is located essentially in a
horizontal plane.
To move the molds 24 and the plenum 33 into position beneath the
press 40, the tubular support 46 is secured to two spaced A-shaped
members 114 (FIGS. 1 and 2) by two collars 115 and 116 journaled
within the upper ends of the members. The collars 115 opposite a
closed end 112 of the support 46 includes a large gear 117 fixed to
the support adjacent the rotatable joint 68, and a hydraulic motor
119 is supported on the frame 30 by a platform 120 located beneath
the gear. The motor is drivingly connected to the gear by way of a
rotatable shaft 121 and a small gear 123 which is mounted on the
shaft to turn the large gear and thereby rotate the arms 31 to
carry the molds toward the press.
Once the molds 24 are located in their predetermined positions
beneath the press 40, the latter is advanced toward the molds from
an upper out-of-the-way position into a lower position to engage
the upwardly facing wall 56 of the plenum 33 and to compress the
dashboards 21 to their desired thicknesses while, at the same time,
squeezing excess water from the dashboards through the molds and
into the two chambers 54 within the plenum. Herein, the press
includes a generally rectangular head 124 (FIG. 7) which is
approximately the same size and shape as the lower wall of the
plenum. The head is connected on the lower end of a fluid-operated
actuator 125 (FIG. 2) secured to the frame 30, the actuator
comprising an elongated rod 126 which projects downwardly from a
cylinder 127 and which is bolted to the center portion of the head.
Preferably, two inflatable bladders 129 (FIG. 7) are sealed to the
underside of the head, each of the bladders being positioned on the
head to compress the dashboard in one of the molds when the head is
clamped to the wall 56 of the plenum 33. Two air lines 130 leading
from the head above each of the bladders provide air from a high
pressure source (not shown) for inflation of the bladders.
Holding the press head 124 and the plenum 33 together as the
bladders 129 are inflated are six clamps 131 (see FIGS. 1 and 2),
three each being mounted on the press head along opposite sides
thereof to lock against front and rear walls 133 and 134 of the
plenum. As shown in FIG. 6, each of the clamps is operated by a
fluid-actuated cylinder 135 mounted on top of the press head and
having a rod 136 projecting beyond the edge of the head. An eye 137
on the end of each rod is pinned to the upper end of a downwardly
extending lever 139 which is mounted by a pivot 140 on the side of
the press head intermediate the ends of the lever. The lower ends
of the levers are hooked inwardly to fit within notches 141 (FIG.
1) located in the front and rear walls 133 and 134 of the plenum to
lock the plenum together with the press head as the rods are
advanced from their cylinders.
Once the press head 124 and plenum 33 are locked together, the
bladders 129 are inflated to compress the dashboards 21 on the
molds 24 while also squeezing excess water through the molds and
into the chambers 54. In accordance with another novel aspect of
the present invention, the plenum 33 and the arms 31 each are
shaped in a novel manner to drain the excess water away from the
molds to avoid rewetting the articles 21 (e.g., the dashboards)
after they are squeezed by the press 40 to remove the excess water.
For this purpose, the plenum and the arms are each constructed, as
shown in FIG. 2, so that walls 142 and 143 of the plenum and the
arms, respectively, slope downwardly toward the tubular support 46
once the arms are swung through the predetermined arc from above
the stock pan 26 to carry the plenum to its predetermined position
(shown in phantom) beneath the press 40. By virtue of this
arrangement, the excess water squeezed from the molded articles
flows by gravity and with the help of the vacuum out of the
chambers 54 (see FIGS. 6 and 7) in the plenum, through the openings
49 in the sides 50 of the plenum and downwardly through the arms
into the tubular support to be collected for reprocessing and
recycling. Thus, the excess water is kept from possibly being
captivated in the plenum to rewet the articles after the latter are
compacted by the press.
Once the dashboards 21 are compacted by the press 40, the main
vacuum valve 39 is closed so the air entering the chambers 54
through the bleed ports 43 breaks the vacuum in the plenum 33, and
the air in the bladders 129 is vented through the air lines 130.
Then, the press head 124 is unclamped from the plenum 33 and is
retracted into its out of the way position. The bleed ports 43 then
are closed by de-energizing the solenoids 60.
To eject the dashboards from the molds 24, the plenum 33 is indexed
on the arms 31, the plenum being pivoted into an inverted position
relative to the arms. Then, pressurized air is forced into the two
chambers 54 to below the dashboards off the molds and onto the
conveyor 41. Herein, the plenum is mounted between the arms on two
pins 144 (see FIGS. 2 and 7), each projecting outwardly from fixed
connections to the opposite sides 50 of the plenum and journaled
through the side walls 145 and 146 of each of the arms. Mounted on
the outer wall 145 of one of the arms is a fluid-actuated cylinder
147 (see FIG. 8) and a toothed rack 148 which is connected on the
end of a reciprocable rod 149 projecting from the cylinder. The
rack meshes with a pinion 150 secured to the outer end portion of
the adjacent one of the pins 144 so that, as the rod is
reciprocated in the cylinder, the rack is moved to turn the pinion
and, in turn, the pin pivotally indexes the plenum relative to the
arms. When advanced, the rod indexes the plenum in a clockwise
direction (as shown in FIG. 8) to invert the plenum relative to the
arms so the wall 56 and molds 24 face downwardly toward the
conveyor 41.
By inverting the plenum 33 relative to the arms 31, the openings 49
in the opposite sides 50 of the plenum are moved out of alignment
with the holes 51 in the inner walls 146 of the arms so that
portions of the sides 50 of the plenum block the holes in the sides
of the arms and thereby seal the chambers 54 in the plenum from the
two branches 47 of the passage 35. At the same time, vertically
extending wings 151 (FIG. 7) on the walls 146 of the arms block the
openings 49 in the opposite sides 50 of the plenum (see FIG. 9) to
seal the plenum from the outside. Ports 152 in the two wings
normally are blocked by the sides of the plenum prior to inverting
the latter relative to the arms but, when the plenum is inverted,
the ports align with the openings 49 in the sides of the plenum
(see FIG. 9). Air pressure lines 153 communicating between the
ports and an air pressure source 128 provide the air for blowing
the dashboards from the molds and onto the conveyor.
After the dashboards 21 are ejected from the molds 24, the plenum
33 is indexed by the rack 148 and pinion 150 back into its original
position relative to the arms 31, and the latter are rotated by
actuation of the motor 119 to carry the plenum and molds back to
their positions above the retracted stock pan 26 (see FIG. 10).
Thereafter, the sprayer 90 is advanced between the empty molds and
the stock pan and is actuated to wash away any pulp fibers adhering
to the outer faces 25 of the molds.
To wash away the pulp fibers, a plurality of elongated nozzles 154
(FIG. 12) are mounted within the shower tray 93 and extend parallel
to the pipes 106. Each of the nozzles includes one end portion 155
extending through the end wall 97 of the tray and an opposite end
portion 156 journaled in a block 157 fixed to the other end wall
98. More particularly, the nozzles are attached to a manifold 158
around a plurality of outlets 159 by pivotable couplings 160. The
manifold communicates with a high pressure water source (not shown)
through an inlet 161 and is supported on the end wall 97 of the
tray by a bracket 162. From the high pressure source, the water
flows into the manifold and is divided thereby to flow into the
nozzles. Each nozzle includes a plurality of orifices 163 which
open upwardly toward the molds and which are spaced from each other
along a substantial portion of the length of the nozzle. By
pivoting the nozzles back and forth about their longitudinal axes,
the water sprayed upwardly through the orifices washes back and
forth across the outer surfaces 25 of the molds to cleanse the
molds of pulp fibers possibly adhering thereto.
Herein, the means for pivoting the nozzles 154 includes a yoke 164
(FIG. 11) disposed below the nozzles and between the manifold 158
and the end wall 97 of the tray 93. A plurality of connectors 165
corresponding in number to the number of nozzles and comprising
parts of the yoke extend upwardly from pivot connections 166 to a
lower crosspiece 167 and are secured to the nozzles between the
couplings 160 and the tray. Extending downwardly from the
crosspiece is a fixed tongue 168 which is attached by a pivot 169
to a rod 170 projecting forwardly from a fluid-actuated cylinder
171 mounted on the underside of the bottom wall 100 of the tray by
an L-shaped bracket 173. When the rod is reciprocated in the
cylinder, the yoke moves back and forth thereby pivoting the
nozzles to spray back and forth across the outer faces 25 of the
molds 24. As with the low pressure spray, the water sprayed from
the nozzles falls back into the tray 93 and is collected for
reprocessing and recirculating and thus is kept from diluting the
slurry 23 in the stock pan 26. Once the molds are cleaned in the
foregoing manner, the motor 105 is actuated to retract the shower
tray from beneath the molds and into its normal rest position
thereby completing one cycle in the operation of the molding
machine 20.
By way of summary, it will be seen that the novel molding machine
20 of the present invention operates in a unique manner to mold
articles 21 such as the exemplary impact-crushable dashboards. To
start the molding machine, the main vacuum valve 39 and the bleed
ports 43 are opened and the vacuum regulator valve 61 is adjusted
to obtain the desired thickness of the dashboards to be formed.
Then, the molds 24 are immersed in the stock pan 26 by raising the
latter with the main cylinders 36 so the vacuum applied to the
plenum chambers 54 through the passage 35 draws the slurry 23 from
the stock pan and through the molds, the latter serving to strain
the pulp fibers from the slurry so that the fibers collect on the
outer faces 25 of the molds to form the dashboards. Advantageously,
the bleed ports 43 in the passage cushion the initial build-up of
the vacuum so the larger and smaller pulp fibers collect uniformly
on the molds throughout the thickness of each dashboard being
formed. Moreover, the ported plates 44 in the stock pan between the
immersion chamber 75 and the inlet chamber 74 keep the pulp fibers
evenly distributed throughout the slurry in which the molds are
immersed. The outside air drawn into the passage by the vacuum also
is used to siphon the white water from the chambers 54 through the
tubes 86 so the water may be removed from the plenum and recovered
for reuse.
Once the dashboards 21 are formed on the outer faces 25 of the
molds 24, the stock pan 26 is retracted and the sprayer 90 is
advanced between the molds and the stock pan to spray low pressure
water against the edges of the molds to wash away pulp fiber
drippings. Thereafter, the sprayer is retracted and the arms 31 are
pivoted by actuation of the motor 119 to carry the molds to their
positions beneath the press 40. The press head 124 then is advanced
to engage the upwardly facing wall 56 of the plenum and is clamped
to the plenum. The bladders 129 on the head are inflated to squeeze
excess water from the dashboards and, by virtue of the novel shape
of the plenum and the arms, the excess water is squeezed from the
dashboards flows by gravity out of the plenum and through the arms
to be returned to the main supply of slurry with the help of the
vacuum.
After squeezing the excess water from the dashboards 21, the vacuum
valve 39 is closed so the air entering the chambers 54 through the
bleed ports 43 breaks the vacuum in the plenum. The air in the
bladders then is vented to permit the press head 124 to be
unclamped from the wall 56 of the plenum. Then, after retracting
the press head, the bleed ports are closed and the plenum is
pivotally indexed on the arms 34 by the rack 148 and pinion 150
into an inverted position to seal the plenum from the passage 35
while at the same time unblocking the ports 152 through which
pressurized air is forced into the chambers 54 to blow the
dashboards off the molds 24 and onto the conveyor 41. Thereafter,
the plenum is indexed back into its original position relative to
the arms, and the arms are swung reversely to carry the plenum back
into position above the stock pan 26. The sprayer 90 then is
advanced between the molds and the stock pan and high pressure
water is sprayed from the nozzles 154 as the latter are pivoted
back and forth across the outer faces 25 of the molds by operation
of the cylinder 147 to wash away pulp fibers clinging to the molds.
After cleansing the molds, the sprayer is rolled back to its normal
rest position from beneath the plenum thereby to complete one cycle
of the molding machine 20.
Another embodiment of the invention is illustrated in FIGS. 13
through 18 where parts corresponding to those described above are
indicated by primed reference numerals. In this embodiment, a
molding machine 20' operates in essentially the same manner as the
molding machine 20, but includes two sets of arms 31' extending in
opposite directions from each other from a rotatable support 46'
(see FIG. 14). Advantageously, each of the sets of arms carries a
plenum 33' thereby doubling the capacity of the molding machine 20'
over that of the molding machine 20.
In the molding operation, the support 46' is rotated through a
complete revolution, stopping each 90.degree. as one of the basic
steps of forming, draining, pressing or ejecting is performed.
Herein, the support is rotated in a clockwise direction as viewed
in FIG. 13, the arms being swung through successive 90.degree. arcs
beginning with the arms oriented vertically.
In the first position, articles 21' (FIG. 15) are formed on molds
24' carried in the lower plenum 33'a while excess water is squeezed
by a press 40' (FIG. 13) from the articles 21' carried in the upper
plenum 33'b. Thereafter, the stock pan 26' is retracted and a
sprayer 90' is advanced between the stock pan and the newly molded
articles to trim pulp fiber drippings from the edges of the mold
with a low pressure water spray. After moving the sprayer back into
its rest position to one side of the stock pan, the arms 31' are
swung 90.degree. clockwise into substantially horizontal positions
and the two plenums are each indexed relative to their respective
arms 90.degree. in a clockwise direction (see FIG. 16) so the
articles in the plenum 33'a face upwardly for draining and the
articles in the plenum 33'b face downwardly for ejection onto a
conveyor 41' (FIG. 13). Once the draining and ejecting operations
are performed, the plenums each are indexed back into their
original positions and the arms are swung through another
90.degree., placing the articles in the plenum 33'a in position for
pressing and the molds in the plenum 33'b in position for forming
new articles from the slurry in the stock pan 26'.
After the articles in the plenum 33'a are pressed and new articles
are formed on the molds 24' in the plenum 33'b and trimmed of pulp
fiber drippings by the sprayer 90' the arms 31' are swung another
90.degree. clockwise and the plenums are indexed 90.degree.
clockwise relative to the arms, positioning the plenum 33'b for
draining and the articles in plenum 33'a for ejection from the
molds onto the conveyor. Thereafter, the plenums again are indexed
back to their original positions relative to the arms and the
latter are swung clockwise through another 90.degree. by the
support 46' as it finishes rotating through one revolution. Then,
to complete one cycle in the operation of the molding machine 20',
the sprayer again is advanced between the molds and the retracted
stock pan, this time to spray high pressure water back and forth
across the surfaces of the molds to cleanse the latter of adhering
pulp fibers.
Because the various steps in the molding process take place at
different times for each of the two plenums 33'a and 33'b, the
interior of the support 46' is divided into two separate passages
35'a and 35'b (FIG. 14) by a partition 180 extending longitudinally
through the support from a rotatable joint 68' to a closed end
portion 112' of the support. A fixed pipe 63' (FIG. 17) leading
from the joint to a vacuum pump 32' also is divded in half by a
partition 181 which extends longitudinally through a portion of the
pipe between the joint and two main vacuum valves 39'a and 39'b
which are mounted in the passages 35'a and 35'b respectively. In
the positions illustrated in FIG. 14, articles 21' are formed on
the molds 24' by evacuating the air from the plenum 33'a and
immersing the molds in the slurry by lifting the stock pan 26' with
the cylinders 36' so the vacuum draws slurry through the molds
causing the fibers in the slurry to collect on the outer surfaces
25' of the molds. At the same time, previously molded articles in
the plenum 33'b are squeezed by the press 40' to remove excess
water from the articles.
With the arms 31' positioned vertically, both of the main vacuum
valves 39' are open as are bleed ports 43' which are located
adjacent the free ends of each of the arms. Also, regulator valves
61'a and 61'b (shown in FIG. 17) are located in each of the
passages 35'a and 35'b, respectively, between the main vacuum and
the rotatable joint 68' and are adjusted so as to achieve the
desired predetermined thickness for the articles 21' being formed.
In the vertical position of the arms, the partition 180 extends
crosswise of the partition 181 (see FIGS. 13 and 14) so the white
water evacuated from plenum 33'a may flow through either or both of
the passages 35'a and 35'b in the fixed pipe 63', past the main
vacuum valves 39'a and 39'b to a separator tank 48' located between
the main vacuum valve and the pump 32'. In the lower plenum 33'a,
the white water in the chambers 54' is drawn from adjacent the wall
56' through siphon tubes 86' as a result of the outside air
entering the branches 47' of the passage 35'a through the bleed
ports 43'. In the upper plenum 33'b, the water squeezed from the
articles flows from the chambers in that plenum, through the arms
and eventually to the separator tank with the white water drawn
from the lower plenum.
Herein, the openings 49' and holes 51' in the end walls 50' of the
plenums and the inside walls 146' of the arms 31', respectively,
are arranged in a slightly different manner than the similar
openings and holes in the first embodiment. Although each chamber
54' includes two openings 49' located in the opposite end walls
50', three holes 51' are formed in the inside walls of each arm so
that, when the arms are in the molding and pressing positions, the
two openings in the walls 50' of the plenums are aligned with two
of the three openings in the arms, the other holes in the arms
being blocked by the adjacent sides of the plenums. Similarly, when
the plenums are indexed 90.degree. relative to their respective
arms, such as when the plenums are positioned for draining and
ejecting, the two openings in the plenum walls still are aligned
with two of the three holes in the arms (compare FIGS. 15 and
18).
After the articles 21' are formed on the molds 24' in the lower
plenum 33'a, the stock pan 26' is retracted and the sprayer 90' is
advanced from its normal rest position on a support 91' adjacent
one side of the stock pan along the tracks 95' and 96' into
position beneath the lower plenum by actuation of a motor 105'.
After pulp fiber drippings have been washed away from the edges of
the molds 24', the sprayer is retracted back to its rest position
and the arms 31' are swung in a clockwise direction through a
90.degree. arc by rotation of the support 46'. As in the first
embodiment, the support is rotated by a motor 119' which drives
gears 123' and 117'. As the support rotates the arms 31' into
horizontal positions, the partitions 180 and 181 align with each
other (see FIGS. 16 and 17) and the plenums each are indexed
90.degree. in a clockwise direction by actuation of cylinders 147'
so the wall 56' of the plenum 33' a faces upwardly and the wall 56'
of the plenum 33'b faces downwardly.
With the two partitions 180 and 181 aligned with each other, the
passages 35'a and 35'b are sealed from each other so that the
vacuum still may be applied to the chambers 54' of plenum 33'a
while pressurized air is forced into the chambers of plenum 33'b.
This is accomplished by leaving the main vacuum valve 39'a open and
closing the vacuum valve 39'b along with the bleed ports 43' which
open into the passage 35'b. Then, to blow the articles off the
molds 24' and onto the conveyor 41', pressurized air is forced into
passage 35'b, through the aligned holes 51' and openings 49'
through the walls 146' and 50' of the arms and plenum,
respectively, and into the chambers 54'. The conveyor 41' then
carries the articles away for further processing. In this
embodiment, only one pressure line 153' (FIG. 17) is used to
deliver pressurized air from an air pressure source 128'. Herein,
the line is connected to the passage 35'b between the regulator
valve 61'b and the joint 68' thereby avoiding separate connections
between the air pressure source and each of the two plenums 33'a
and 33'b.
With the plenum 33'a in position for draining, any white water left
in that plenum and the arms 21' flows, with the help of the vacuum,
into the passage 35'a and toward the separator tank 48'.
Advantageously, each of the plenums is shaped in such a fashion so
as to facilitate drainage of the white water toward the support
pipe 46'. In each plenum, a wall 142' opposite the lower wall 56'
is comprised of two sections 183 and 184 (FIG. 18), one covering
one of the chambers 54' in the plenum and the other section
covering the other chamber. Each of the sections slants toward the
lower wall upon progressing outwardly from the center of the
plenum. Thus, when the plenums are positioned for draining, the
white water drains toward the center of the plenums through the
aligned openings 49' and holes 51' and into the arms 31' both as a
result of the vacuum and gravity.
Once the draining and ejecting steps of the molding process are
completed, the plenums 33'a and 33'b are indexed back to their
original positions relative to their respective arms 31'. At this
point, an extension 185 (FIG. 13) of the conveyor 41' is pivoted
counterclockwise into a position as shown in FIG. 13 to locate the
extension out-of-the-way so the plenum 33'b may be swung into
position above the retracted stock pan 26'. Herein, the extension
comprises a plurality of belts 186 trained around rollers 187 and
driven by a roller 188 which also serves as the end roller of the
stationary portion of the conveyor. A pivotal arm 189 connected
between the rollers is supported vertically by a rod 190 extending
outwardly of a cylinder 191 which is mounted on a member 192
supporting the conveyor. The outer end of the rod is pinned to the
outer end of the arms and normally is advanced from the cylinder so
the belts are supported horizontally to receive the articles 21'
blown from the molds 24'.
To move the conveyor extension 185 out of the way, the rod 190 is
retracted within the cylinder 191, thereby pulling the arm 186
downwardly in a counterclockwise direction as shown in FIG. 13 so
the arms 31' may be swung past the conveyor to position the plenum
33'b above the stock pan 26' and the plenum 33'a below the press
40'. Once the arms are again oriented vertically, the cylinder is
actuated to advance the rod and thereby reposition the conveyor
extension so that it extends in a horizontal position. At about the
same time, the forming and pressing steps are repeated with new
articles being formed on the molds 24' being carried by plenum 33'b
and the articles carried by plenum 33'a being squeezed of excess
water by the press 40'.
Thereafter, the arms 31' are swung another 90.degree. clockwise and
the plenums are indexed, carrying the plenum 33'b into its draining
position and the plenum 33'a into position for ejecting the
articles 21' from the molds 24' in that plenum. It will be
appreciated that in these positions, the partitions 180 and 181
again are aligned with each other so the portions of the passages
35'a and 35'b within the support 46' now align with the stationary
portions of the passages 35'b and 35'a, respectively, leading to
the separator tank 48' and pump 32'. Accordingly, the portion of
passage 35'b extending from the main vacuum valve 39'b to the joint
68' is alternately pressurized and subjected to vacuum during the
molding process while the portion of the passage 35'a extending
from the main valve 39'a to the joint 68' is continually subjected
to vacuum.
Once the plenum 33'b is drained of excess white water and the
articles 21' are ejected from the molds 24' on the plenum 33'a and
carried away by the conveyor 41', the latter is moved into its
out-of-the-way position and the plenums are indexed 90.degree.
counterclockwise to be swung with the arms 31' through 90.degree.
arcs so plenum 33'a is positioned above the stock pan 26' and the
plenum 33'b is positioned below the press. The conveyor then is
swung back into its horizontal position and the sprayer 90' is
advanced from its support 91' and into position between the plenum
and the stock pan for spraying high pressure water back and forth
across the outer faces of the molds 24' to cleanse the latter of
pulp fibers adhering to the molds. One cycle of the molding
operation of the molding machine 20', then is completed by
retracting the sprayer from between the stock pan 26' and the
plenum 33'a preparatory to the beginning of the next cycle.
* * * * *