US 3804570 A
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.
Description (OCR text may contain errors)
United States Patent [191 Hiischele et al.
[ Apr. 16, 1974 BLOCK PRESS  Assignee: Werner & Pfleiderer, Stuttgart,
Germany 22 Filed: Nov.2, 1972  Appl. No.: 303,284
 Foreign Application Priority Data Nov. 19, 1971 Germany 2157465  US. Cl 425/261, 425/355, 425/420, 1 V 1 425/422, 425/78, 425/812  Int. Cl. B29c 3/04  Field of Search 425/256, 261, 352, 355, 425/354, 420, 422, 804, 808, 812, 78
.  References Cited UNITED STATES PATENTS 2,481,232 9/1949 Moore 425/352x 2,598,016 5/1952 Richardson, Sr. 425/78 X' 2,904,835 9/1959 Thomas .1 425/78 3,172,156 3/1965 1314mm... 425/352 x 3,191,232 6/1965 Haller 425/78 3,209,057 9/1965 .Lassman. 425/420 X 3,225,410 12/1965- Boyer 425/352 3,613,166 10/1971; Wallace et a1. 425/352 7/1972 Bowles 425/261 7 Primary Examiner-Robert L. Spicer, Jr.
Attorney, Agent, or Firm-Plane, Baxley & Spiecens [5 7] ABSTRACT There is disclosed a press such as a hydraulic press for forming form-retaining blocks by compacting powderize d 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 theupper 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 sec- 0nd plunger is accompanied by activating the vacuum 9 Claims, 4 Drawing Figures PATENTEBAPRIsIQM' 3804,570-
sman a or 2 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 utilizationstation. 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 sufficientextent. As previously stated, the formretaining 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, .whenfed 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 inovement 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 bottomof 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 thepressure plunger. To this end, the servo cylinder-piston unit is disposed co-axially to thepressure container. r
Precornpression 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 withthe respective pressure plunger. i I
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 ofa 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 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 engage'able 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 con-' tainer 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 compres sion position (Iefthand positionlin 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 compressionplunger '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 positiondue 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.
What is claimed is:
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 selecte'd 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 selected axial position within said container.
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 by varying the position of the piston in the cylinder.
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 the same to a selected level.
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 sucking out of air occluded in the material.
5. The press according to claim 4 wherein a gearing means couples said piston rod to said first plunger and vacuum means.
6. The press according to claim 1 wherein said vacuum means encompasses said first plunger coaxially therewith.
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 compression position.
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 compression position.
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.