U.S. patent number 3,804,570 [Application Number 05/303,284] was granted by the patent office on 1974-04-16 for block press.
This patent grant is currently assigned to Werner & Pfleiderer. Invention is credited to Gunter Hoschele, Eugen Kopp, Heinz Kroner, Xaver Strobl.
United States Patent |
3,804,570 |
Hoschele , et al. |
April 16, 1974 |
BLOCK PRESS
Abstract
There is disclosed a press such as a hydraulic press for forming
form-retaining blocks by compacting powderized or fibrous material.
The press comprises two pressure containers which are pivotal about
a common axis for automatically and selectively placing the
containers in a filling position and a compression position,
respectively. The bottom of each container consists of a pressure
plunger which is slidable in the respective container and can be
releasably locked in any selected axial position. There is further
provided a second pressure plunger and a vacuum device disposed
adjacent to the upper end of the container in the compression
position. Filling of the container in the filling position is
effected by extending a feed pipe into the container to be filled.
Compacting or compression of the material in a container is
effected by moving the two plungers toward each other. The pressure
stroke of the second plunger is accompanied by activating the
vacuum device for sucking out air initially occluded in the
material and released therefrom as the compression progresses. The
press has, among others, the advantage that only one vacuum device
is required and that filling and compacting operations can be
carried out side by side.
Inventors: |
Hoschele; Gunter (Gerlingen,
DT), Kopp; Eugen (Stuttgart, DT), Kroner;
Heinz (Lauffen/Neckar, DT), Strobl; Xaver
(Stuttgart, DT) |
Assignee: |
Werner & Pfleiderer
(Stuttgart, DT)
|
Family
ID: |
5825579 |
Appl.
No.: |
05/303,284 |
Filed: |
November 2, 1972 |
Foreign Application Priority Data
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|
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Nov 19, 1971 [DT] |
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2157465 |
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Current U.S.
Class: |
425/261; 425/78;
425/355; 425/405.1; 425/420; 425/422; 425/812 |
Current CPC
Class: |
B30B
11/10 (20130101); Y10S 425/812 (20130101) |
Current International
Class: |
B30B
11/02 (20060101); B30B 11/10 (20060101); B29c
003/04 () |
Field of
Search: |
;425/256,261,352,355,354,420,422,804,808,812,78 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Spicer, Jr.; Robert L.
Attorney, Agent or Firm: Hane, Baxley & Spiecens
Claims
1. A press for compacting discrete particles of materials to
form-retaining blocks, said press comprising in combination:
a first and a second generally cylindrical pressure container open
at its ends;
a support column pivotally supporting said containers parallel to
each other and said column for pivoting the containers about the
axis of said column alternately into a compression position and a
filling position;
feed means for feeding material to be compressed into the container
in the filling position; and
compression means for compressing material in the container in the
compression position, said compression means including
a pressure plunger and a vacuum means disposed adjacent to one end
of the container in the compression position, said plunger being
slidable in said container for applying compacting pressure in one
direction upon material in the container and said vacuum means
communicating with the container for sucking out air occluded in
the material and to release therefrom during said compression,
and
a second pressure plunger for each container, each of said second
plungers constituting the bottom of the respective container at the
other end thereof and being slidable in the respective container
for applying compacting pressure in the direction opposite to the
pressure direction of the first plunger and a clamping means on
each second plunger for releasably holding each second plunger in a
selected axial position within the respective container by pressure
engagement therewith, and
actuating means co-acting with the second plunger of the container
in the compression position for moving the respective second
plunger into a
2. The press according to claim 1 where said actuating means
comprise a servo unit including a cylinder, a piston slidable in
said cylinder and a piston rod mounted on the piston, said piston
rod being movable into and out of engagement with the second
plunger of the container in the compression position for varying
the axial position of said second plunger
3. The press according to claim 1 where said feed means comprise a
first feed pipe stationarily mounted in axial alignment with said
one end of the container in the filling position and a second feed
pipe telescopically supported on the first feed pipe at the end
thereof facing said container, said second pipe being extendable
into the container to feed material into
4. The press according to claim 1 and comprising a servo unit
disposed adjacent to said one end of the container in a compression
position, said servo unit including a cylinder, a piston and a
piston rod secured to the piston, said piston rod being coupled to
the first pressure plunger and the vacuum means for selectively
displacing the first plunger and the vacuum means relative to said
container so as to effect compression and
5. The press according to claim 4 wherein a gearing means couples
said
6. The press according to claim 1 wherein said vacuum means
encompasses
7. The press according to claim 1 wherein said vacuum means is
displacable into a position spaced apart from the first plunger,
and wherein a servo unit co-acts with said vacuum means for moving
the same into and out of sealing engagement with the rim at said
one end of the container in the
8. The press according to claim 1 wherein the other end of each
container constitutes an ejection end for removing from the
respective container a finished block formed of compacted material,
and wherein conveying means are disposed adjacent to said other end
of the container in the
9. The press according to claim 8 and comprising a sweeping means
for moving a finished block ejected from the container upon the
conveying means, said sweeping means including a second column
mounted parallel to said first column and a sweeper arm pivotally
supported on said second column.
Description
The invention relates to a press for producing form-retaining
blocks by compressing discrete particles such as powderized or
fibrous material. Blocks of this kind are widely used to facilitate
transportation of the material and also further processing
thereof.
BACKGROUND
One of the problems in the production of blocks of the general kind
above referred to is that the material generally contains a
considerable amount of occluded air which must be removed to obtain
a strength of the blocks so that the same can be safely conveyed to
a utilization station. Generally, the form-retaining strength of
compressed powderized or fibrous materials depends largely on the
extent to which the occluded air is removed from the material.
There are known presses for the general purpose above referred to
which include a filling station, a pressure station and a block
removable station. These stations are coupled to each other and
pivotal about a common axis. Compacting of the discrete particles
constituting the material in the pressure station is mechanically
effected in that a pressure plunger driven by a threaded spindle
presses the material to be compacted against a perforated closure
plate which is connected to a source of vacuum.
As presses of the above referred to type require three stations,
they are expensive to construct and to service. Moreover,
compacting of the material is effected in one stage, that is,
without precompression and such one-stage compacting, especially
with some types of material is not capable of removing the occluded
air to a sufficient extent. As previously stated, the
form-retaining strength of the blocks is largely dependent on the
extent to which the air is removed therefrom and a limited removal
of air has been found to be frequently the cause of crumbling or
cracking of the blocks during transportation.
There is also known a press in which the material to be compacted
is subjected to a precompression at a low pressure and subsequently
to a finishing compression at a higher pressure. In presses of this
type, the pressure container for the material is pivotally arranged
so that it can be turned first into cooperative engagement with a
precompression plunger and then with a finishing pressure plunger.
Presses of this kind have the disadvantage that neither during the
precompression nor during the finishing compression, evacuation of
the material is possible. As pointed out before, the extent of the
evacuation of the air is a very important factor for the strength
of the finished blocks. It has been found that loose or fluffy
material of the kind here involved, when fed into the pressure
container tends to increase the occlusion of air to a considerable
extent. When such fluffed-up material is subjected to the
precompression, the air remains occluded within the material as it
cannot escape during the final compression. If now the temperature
of the blocks increases for any reason, the multitude of air
bubbles occluded in the material will expand and cause crumbling of
the block.
THE INVENTION
It is the broad object of the invention to provide a novel and
improved press of the general kind above referred to, which permits
filling, precompressing and final compressing of the material in a
manner such that optimally evacuated blocks are produced in a rapid
manner.
Another object of the invention is to provide a novel and improved
press of the general kind above referred to which is simple in
construction and can be operated in a highly economic manner in
that compression of material, evacuation of air occluded in the
material and ejection of finished blocks are sequentially effected
in continuous operation and that, moreover, a second container can
be simultaneously filled for movement into the compression station,
thereby considerably reducing the production time.
SUMMARY OF THE INVENTION
The pointed out objects, features and advantages and other objects,
features and advantages which will be pointed out hereafter are
obtained by providing at the bottom of each pressure container a
pressure plunger which can be releasably locked by frictional
pressure in any selected axial position within the respective
container. The provision of such adjustable plungers as bottoms for
the containers permits to vary the storage capacity of the
containers as desired during the operation. By suitably setting the
positions of the plungers the return stroke of the plungers, which
of course constitutes lost or idle time, can be held at a minimum.
Moreover, the extent of compression of the material and the manner
in which the same is filled into the container can be conveniently
adapted to the optimal requirements of the material to be
compressed.
The work stroke and the return stroke of the pressure plunger
constituting the bottom of the container may be effected by any
suitable means; the use of a servo unit has been to be particularly
advantageous. The piston of such servo unit mounts a rod which
co-acts directly with the pressure plunger. To this end, the servo
cylinder-piston unit is disposed co-axially to the pressure
container.
Precompression and final compression are effected in one pressure
container according to the invention. Moreover, optimal withdrawal
of occluded air is obtained by subjecting the mateial to suction
action already during the precompression by means of a vacuum
device which co-acts with the respective pressure plunger.
According to a further aspect of the invention, the feeding
assembly of the press comprises a feed pipe which is disposed
co-axially with a container in the filling position and is
stationarily mounted. A second feed pipe is telescopically
supported by the stationary feed pipe and can be displaced,
preferably by a suitable servo unit, to extend into a compression
container to be filled. With such an arrangement, the level to
which a container is filled can be easily controlled during the
filling operation while the compression operations progress without
interference in the compression station. After filling the
container to the desired level, the movable feed pipe is withdrawn
from the container.
According to still another aspect of the invention, the pressure
plunger constituting the bottom of the containers can be lowered
relative to the end of the feed pipe by means of the afore referred
to servo unit when the container is in the filling position. The
particular advantage of such an arrangement is that filling of the
material can be effected without intrusion of air. Due to the
gradual lowering of the pressure plunger the material is in effect
sucked into the container by gravity action causing it to follow
the pressure plunger as the same is lowered. Accordingly, some
compression of the material is already obtained during the filling
operation.
To carry out the final compression operations in the pressure
container, it is advantageous that the servo unit which operates
the pressure plunger constituting the bottom of a container in the
filling station is locked in position by preventing an escape of
the pressure fluid conventionally used in servo units of the kind
here involved. This has the advantage that the pressure plunger now
in effect constitutes a stationary bottom which limits the pressure
container to the desired volume.
The invention also contemplates that the cylinder of the servo unit
and the respective plunger are coupled by pressure transmitting
means to activate both the servo cylinder and said plunger
connected therewith simultaneously but opposite direction. This has
the advantage that with certain materials which can be sufficiently
compressed without precompression, especially if sieves are
provided for the filling operation, so that a uniform density of
material within the finished block can be obtained.
Sucking air from the material during the precompression step and
the final compression step can be advantageously effected by
arranging the vacuum means concentrically with the respective
pressure plunger. Moreover, the vaccum means is preferably so
arranged that it can be separated from the pressure plunger and be
placed in sealing engagement with the facing rim of the pressure
container by a suitable servo unit.
To effect automatic conveyance of the finished blocks, it is
provided that each pressure container has at its ejection end a
hydraulically or pneumatically operated device for pushing blocks
as they emerge from the container upon a suitable conveyor. The
pressure plunger serving as bottom for a container can be
advantageously and conveniently used as a means for ejecting a
finished block from the respective container.
BRIEF DESCRIPTION OF THE INVENTION
In the accompanying drawing, a preferred embodiment of the
invention is shown by way of illustration and not by way of
limitation in the drawing:
FIG. 1 is an elevational sectional view of a hydraulic block
producing press, according to the invention;
FIG. 2 is a detailed view of a part of FIG. 1 on an enlarged scale
and, more particularly, of a plunger or ram of the press;
FIG. 3 is a plan view of FIG. 1; and
FIG. 4 is a section taken on line IV -- IV of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawing figures more in detail, the press
according to the invention comprises two cylindrical pressure
containers or pots 1 and 2 open at their ends. The containers are
pivotal about a column 3 and joined by a cross-wise bracket 8. The
press further comprises a second column 4 and an upper and a lower
head portion 5 and 6, respectively. A bearing assembly for column 3
comprise an axial bearing 7, which springingly abut against the
lower head 6 and an axial bearing 9 for the upper head 6.
The two containers 1 and 2 are reversible through 180.degree., by
means of a hydraulic rotary piston 10 via a gearing 11 and an
intermediate member 12, so that the two containers can be
alternately placed in the operating position.
Compression plungers or rams 13 and 14 are displaceable in vertical
direction in containers 1 and 2. The plungers constitute the bottom
of the containers, and as it is shown in detail, in FIG. 2, the
plungers are slidably guided by means of guide rings 15 and 15',
respectively, on the inner walls of the containers. To effect an
adequate sealing of the compression spaces above and below the
plungers, sealing rings 16 and 17 are provided.
Both plungers can be locked in position by a clamping means in any
selected position relative to the inner wall of the containers by a
frictional between the plunger and the respective inner wall. This
clamping means comprises, according to the FIG. 2 a clamping or
pressure ring 18 and set screws 19, which co-act with the guide
ring 15' and the sealing ring 17. The pressure exerted by the
clamping means and lock the frictional force with which the
plungers are pressed against the inner wall of the press containers
can be varied within the desired limits by appropriately tightening
the set screws.
The actuation of the plunger, which is in the compression position
(the lefthand plunger) is effected by a pressure cylinder which is
disposed co-axially with container 1 and a piston 21. This piston
is engageable via its piston rod 21' with the pressure plunger in
any position thereof within the respective container. For this
purpose, pressure cylinder 20 is secured to the lower crosshead 6
of the press.
The upper crosshead 5 mounts a pressure cylinder 22 in which a
pressure piston 24 acting as compression member is disposed
co-axially with the pressure container 2. Accordingly, pressure
plunger 14 and compression piston 24 act in opposition.
Piston 24 is concentric with a cap-shaped vacuum device 27, so that
a shoulder on piston 24 co-acts with a shoulder 26 in a manner such
that the vacuum device is returned into its starting position
during the return stroke of piston 24.
Sealing rings 28 and 29 prevent ingress of air during the
evacuation of the material to be compacted consisting, as
previously stated, for instance, of discrete particles or of
fibers. Evacuation is effected when the vacuum device is lowered by
means of pressure cylinders 30 and 30' into sealed engagement with
the rim of the compression cylinder. The vacuum device is provided
with a suction connector 31 to effect withdrawal of air from the
pressure container.
Actuation of pressure plunger 13 when in the filling position
(righthand position) is effected by a feed pipe 32, which is
vertically slidable on a stationarily mounted feed pipe 33 and thus
constitutes an extension of pipe 33 when it is partly pulled out of
the same. Displacement of the movable pipe 32 is effected by a
suitably disposed pressure cylinder 34.
FIG. 3 shows an assembly for removing finished blocks. A lever 35
is mounted on column 4 and is operable by a rotary member. By
pivoting lever 35 a finished block ejected from the respective
pressure container is transferred to a conveyor means 50 such as a
conveyor band, which is presumed to be conventional and is hence
not shown in detail.
FIG. 4 shows in detail the means for locating the pressure
containers by flanges or other suitable protrusions. As in the
final position of pressure containers 1 and 2, considerable
rotating masses must be braked, correspondingly powerful braking
means are provided. The required braking or retardation is effected
in the exemplified press by shock absorbers or cushioning devices
37 and 37', respectively. These devices are fixedly mounted on the
frame structure of the press, as formed by columns 3 and 4, and the
upper and lower crosshands 5 and 6. A lug 39 or other suitable
abutment member is secured to bracket 8, and is hence pivotable in
unison with pressure containers 1 and 2. This lug 39 is retarded by
devices 37 and 37' while being pivoted in unison with containers 1
and 2 as it approaches and finally engages the adjustable limit
stops 40 and 40'.
The operational cycle of the press is initiated by placing the
pressure containers in positions which they engage limit stops.
Such positioning of the containers can be conveniently effected by
an electric control system of conventional design (not shown).
Filling of the press starts with lowering the movable feed pipe 32.
The quantity and thus the volume of the discrete particles or other
material to be fed into the press is controlled by selecting the
extent of the lowering of the movable pipe by correspondingly
setting the stroke of the piston in the pressure cylinder 34. Such
setting can also be conveniently effected by a suitable electric
control system (not shown). As the movable pipe 32 pushes the
pressure plunger 13 downwardly during the feeding operation, the
loose particles fed into the pressure container are subjected to
suction action. This manner of filling effectively and
advantageously prevents a fluffing of the material with which the
press is charged.
The filled container is then pivoted into the compression position
(lefthand position) in which the material in the container is
compressed or compacted to the desired extent and the formed
finished block is then ejected from the respective container. In
the event the material to be compressed is of a type which makes it
difficult to remove the occluded air, it is advantageous to carry
out the compression or compacting of the material in two steps, one
step being the precompression step and the other the finishing
compression step.
The next step of operation is to lower the precompression plunger
together with a vacuum device to the level of the material in the
pressure container 2. By applying pressure to pressure piston 21,
the compression plunger 14 compresses the material against the
precompression plunger 24, thereby reducing the volume of the
material in container 2. At the same time, the pressed-out air is
sucked off through the suction duct 31 of the vacuum device 27.
Upon completion of the displacement of the piston 21, the piston is
retained in its position for instance by closing the backflow
acting upon the piston, so that the final compression can be
effected by moving the compression plunger 24 toward the stationary
compression plunger 14.
The subsequent removal of the now finished block of material from
the respective pressure container (container 2) is effected by
renewed operation of the piston 21. The finished block is clamped
in a tongue-like fashion between the compression plunger 24 and the
plunger 14, and carried out over the rim of the pressure container.
A wiper 35' on lever 35 then pushes the finished block on the
before referred conveying means 50, which should be visualized as
being in position ready for receiving the block. The lever is
pivotal for instance by means of a conventional pneumatic means.
Simultaneously, piston 21 returns into its starting position, while
the compression plunger 14 remains in its upper position due to the
as described clamping means 15, 15' and 19. After pivoting of the
containers, as previously described, the compression plunger can be
lowered by means of the movable feed pipe 32.
The aforedescribed function of the press has the advantage of an
uninterrupted sequence of all operations. Moreover, precompression
and final compression in one of the pressure containers can be
carried out simultaneously with the filling operation in the other
pressure container.
By effecting the precompression and the final compression in the
same container, only one vacuum device is required. The volumes of
the filled-in material and the volumes of the compressed material
are freely adjustable within the limits of the total volume of the
pressure containers. Accordingly, the function of the press can be
readily adapted to the specific requirements of the materials to be
compacted.
While the invention has been described in detail with respect to a
certain now preferred example and embodiment of the invention, it
will be understood by those skilled in the art, after understanding
the invention, that various changes and modifications may be made
without departing from the spirit and scope of the invention, and
it is intended, therefore, to cover all such changes and
modifications in the appended claims.
* * * * *