Title:
METHOD AND APPARATUS FOR PACKING COMPRESSIBLE MATERIAL SUCH AS TOBACCO
United States Patent 3824758
Abstract:
Material such as leaf or strip tobacco is compressed between bale boards in a compression chamber, compression being carried out by a press ram engaging one of the boards and with pressure adequate to compress the material to a smaller mass than is ultimately to be obtained. The means defining the compression chamber is removed and the press ram is then backed off a predetermined small distance, allowing the compressed mass to expand toward the desired final size. Before the compressed mass has expanded adequately to cause excessive friction between the ram and the bale board it engages, the combination of the compressed mass and the bale boards is pushed laterally, away from the press ram, and is then retained by rollers engaging the bale boards while strapping is applied.


Inventors:
Hart, Joel C. (Richmond, VA)
Traughber Jr., Charles W. (Candler, NC)
Application Number:
05/358952
Publication Date:
07/23/1974
Filing Date:
05/10/1973
Assignee:
British-American Tobacco Co., Ltd. (London, EN)
Fisburne International, Inc. (Asheville, NC)
Primary Class:
Other Classes:
53/436, 100/3, 100/7, 100/215, 100/218
International Classes:
A24B1/10; (IPC1-7): B65B13/20; B65B63/02
Field of Search:
53/24,124A,124C,124D,124TS 100
View Patent Images:
US Patent References:
Primary Examiner:
Mcgehee, Travis S.
Attorney, Agent or Firm:
Roylance, Abrams, Berdo & Kaul
Claims:
What is claimed is

1. In the pressing of tobacco and the like into bales by means of a press comprising a support, a charger and compression chamber movable between a first position, in which the compression chamber is removed from the support, and a second position, in which the compression chamber is operatively disposed relative to the support, and a press ram movable through the charger and into the compression chamber to form a compressed mass of tobacco in the compression chamber, the improvement comprising

2. In a press of the type comprising a support, a compression chamber mounted for movement between a first position, in which the chamber is spaced from the support, and a second position, in which the chamber is operatively disposed relative to the support, the support being adapted to receive a first baling board and the compression chamber having access means via which a second baling board can be inserted, and a press ram movable through the charger and into the compression chamber to form a mass of compressed material against the first baling board, the combination of

3. The combination defined in claim 2, wherein the support comprises a pressure plate having a flat face directed toward the press ram, and the press ram has an opposing flat face,

4. The combination defined in claim 2 and further comprising

5. The combination defined in claim 2, wherein said confining means comprises a plurality of rollers disposed to engage the exposed faces of the bale boards.

6. The combination defined in claim 2, wherein the support comprises

7. The combination defined in claim 3 and further comprising

8. The combination defined in claim 7, wherein said confining means comprises a plurality of rollers disposed to engage the exposed faces of the bale board.

9. The combination defined in claim 4, wherein the support comprises

10. The combination defined in claim 4, wherein said confining means comprises a plurality of rollers disposed to engage the exposed faces of the bale boards.

Description:
BACKGROUND OF THE INVENTION

It is advantageous to compress certain materials, particularly leaf tobacco and strip tobacco, into rectangular bales which are retained in their compressed size and shape by bale boards applied to two opposite sides of the bale and, e.g., steel strapping secured about the bale. Such bales are superior to hogsheads because, being rectangular, they can be handled by lift trucks and easily stacked to achieve maximum use of space. Additionally, even when the bale is enclosed in a paperboard container, the cost of materials for the bale is but a fraction of the cost of a hogshead or case.

To prepare such bales, however, it has been necessary to apply the steel strapping or the like while the bale is held under some compression by the press ram. Doing so adds significantly to the total cycle time for the press and, therefore, constitutes a serious drawback from the standpoint of economy.

OBJECTS OF THE INVENTION

A general object of the invention is to provide a method and apparatus whereby bales of the type described can be produced, complete with strapping, without requiring the strapping to be applied while the bale is still held by the press run.

Another object is to devise such a method and apparatus which make use of the expansion rate of compressed material in order to make it possible to remove the bale from the press without having to overcome large frictional forces, yet still attaining the desired dimensions of the bale.

A further object is to devise such a method and apparatus which makes it possible to achieve maximum production efficiency with a ram-and-compression chamber type of baling press.

SUMMARY OF THE INVENTION

The invention is especially applicable to packing of leaf or strip tobacco into bales by means of a press of the type comprising a support upon which one bale board is placed, a movable assembly including a compression chamber and a charger so arranged that the assembly can be lowered to locate the compression chamber over the first bale board, the tobacco then being supplied to fill the compression chamber and charger, a press ram then being forced through the charger and into the compression chamber to compress the mass of tobacco to a height less than that desired for the bale, the ram then being retracted and the second bale board inserted on top of the compressed tobacco, and the ram then again being operated to complete the pressing of the bale. According to the invention, the last pressing step is made such as to compress the mass of tobacco to a dimension (in the direction of travel of the ram) less than that desired for the bale, the compression chamber is removed, the ram is retracted to a position such that the bale can expand to the desired dimension, and, while the tobacco is expanding, the combination of the compressed mass of tobacco and the bale boards is forced laterally until free of the press ram, the bale being immediately received between restraining guides, typically rollers engaging the bale boards, to prevent further expansion. With the bale thus properly formed, but now free from the press, steel strapping or the like is applied while the bale is still restrained.

In order that the manner in which the foregoing and other objects are achieved according to the invention can be understood in detail, one particularly advantageous embodiment thereof will be described with reference to the accompanying drawings, which form a part of the original disclosure hereof, and wherein:

FIG. 1 is a side elevational view of a tobacco baling press according to one apparatus embodiment and capable of use in practicing the method;

FIGS. 2 and 3 are transverse sectional views taken generally on lines 2--2 and 3--3, FIG, 1, respectively;

FIG. 4 is a side elevational view of the compression chamber of the apparatus of FIG. 1;

FIG. 5 is a fragmentary elevational view taken generally on line 5--5, FIG. 4;

FIG. 6 is a vertical sectional view taken generally on lines 6--6, FIG. 3;

FIGS. 7-7B are semi-diagrammatic views illustrating the method as practiced with the apparatus of FIGS. 1-6; and

FIG. 8 is a sectional view taken generally on line 8--8, FIG. 7.

DETAILED DESCRIPTION OF THE APPARATUS

Referring first to FIGS. 1-6, the apparatus comprises an upright main press frame, indicated generally at 1, the base of the frame being situated in a floor well 2, and the frame extending in rigid fashion upwardly above the floor 3. Main frame 1 is of rectangular transverse cross section and comprises vertical side members 4 and cross members 5, the lowermost set of cross members 5a being disposed below the level of floor 3. In addition to frame 1, the apparatus employs a charger frame 6 and a weight frame 7. Frame 6 rigidly supports an elongated vertical tubular charger 8 and in turn is movably supported by rollers 9 mounted on main frame 1. Charger 8 is of rectangular transverse cross section throughout its length and the upper end portion of the charger is telescopically engaged over the lower end portion of an upright filling chute 10 which is fixedly secured in any suitable fashion to the main frame 1.

Frame 7 is of a rectangular transverse cross section similar to but slightly smaller than the main frame and includes vertical side members 11, transverse bottom members 12 and transverse top members 13. One parallel pair of the bottom members 12 is interconnected by a plurality of horizontal supports 14 on which is mounted a set of spaced, parallel, vertical support plates 15. A plurality of pressure fluid operated rectilinear power devices 17, FIG. 1, supported on the bottom of well 2 and forming part of a conventional weighing scale (not shown) are connected to frame 7 in such fashion that the power devices 17 can be operated selectively to raise and lower frame 7 through a relatively small distance. Cross members 5a of main frame 1 support a plurality of flat support plates 18 which lie in parallel vertical planes and are so arranged that each plate 18 projects upwardly midway between a different pair of the plates 15 carried by frame 7. The amount of vertical travel which can be imparted to frame 7 by power devices 17 is such that plates 15 can be located in an upper, operative position (seen in FIG. 1) in which the upper edges of plates 15 are above the upper edges of plates 18, or in a lower, retracted position in which the upper edges of plates 18 are disposed above the upper edges of plates 15. As best seen by comparing FIGS. 3, 6, 7 and 8, plates 15 and 18 cooperate with a flat support or pressure plate 19, the lower face of pressure plate 19 having a set of parallel grooves 15a, to engage over the upper edge portions of plates 15, and a second set of grooves 18a, to engage over the upper edge portions of plates 18.

To supply loose compressible material, such as leaf or strip tobacco, to filling chute 10, there is provided an infeed conveyor 21, FIG. 1, and a suitable distributor (not shown) operative to distribute the loose material uniformly over the transverse cross section of chute 10 and charger 8. The apparatus includes a press head or ram 22 carried by a vertical shaft 23 equipped with a piston (not shown) to operate in an elongated vertical hydraulic power cylinder 24 so arranged that operation of the power cylinder and piston is effective to force ram 22 downwardly through chute 10 and charger 8 and then return the same to the elevated position shown in FIG. 1.

Rigidly secured to the lower end of charger 8 is a compression chamber-defining structure indicated generally at 25 in FIG. 1 and shown in detail in FIGS. 4 and 5. Structure 25 is of rectangular transverse cross-section similar to that of charger 8 and comprises flat side walls 26, vertical exterior strengthening ribs 27 and three horizontal exterior reinforcing members 28. The upper end in a structure 25 is defined by transverse right angle members 29 so disposed that webs 29a of members 29 lie in common plane and can be secured directly to a matching flange on the lower end of charger 8. The bottom end of structure 25 is open and is equipped with an axially short downwardly and outwardly flaring flange 30 for a purpose later described.

The uppermost one of horizontal reinforcing members 28 is spaced below the top of structure 25 by a significant distance. In the space between member 29 and the uppermost member 28, one of the side walls 26 is provided with an aperture 31, FIG. 5, which extends transversely, as an elongated rectangle, for the full width of the interior of the compression chamber-defining structure. Advantageously, the wall 26 in which aperture 31 is provided is one which extends at right angles to plates 15 and 18. At each corner of the compression chamber-defining structure adjacent an end of aperture 31, structure 25 includes an upright exterior reinforcing strip 32, FIG. 5, and the combination of each such strip and the wall 26 which it overlies is provided with a shallow rectangular notch 33 corresponding in height to the vertical dimension of aperture 31. Cooperating with aperture 31 is a closure member 34 in the form of a metal bar of L-shaped transverse cross section and of a length equal to the space between the outer faces of the two reinforcing strips 32, the width of one web 35 of member 34 being such as to fit snugly in the notches 33. A cylindrical metal bearing sleeve 36 is welded or otherwise secured to the outer face of the other web 37 of member 34, sleeve 36 extending along a line near and parallel to the junction between webs 35 and 37. Sleeve 36 is shorter than member 34 and is centered with respect to the length of that member. Two short sleeves 38, FIG. 4, are secured as by welding to the side wall 26 immediately below aperture 31 and are aligned coaxially and parallel to the bottom edge of the aperture. A shaft 39 extends completely through the combination of sleeves 36, 38, so that closure member 34 is supported for pivotal movement, about the axis of shaft 39, between a position closing aperture 31 (as seen in solid lines in FIG. 5) and a position such that aperture 31 is completely open (as seen in broken lines in FIG. 5).

Closure member 34 is operated by two pressure fluid operated piston-and-cylinder type power devices 40. The cylinder 41 of each device 40 is pivotally mounted on the intermediate transverse reinforcing member 28, by a clevis 42, so that the devices 40 can swing about the common transverse axis established by the clevis pins 43. Clevises 44 are secured to the free ends of piston rods 45. Two apertured plates 46 are welded to web 35 of closure member 34 and project away therefrom above web 37, each clevis 44 being connected to a different one of plates 46 by a clevis pin 47. When the power devices 40 are operated to extend piston rods 45, member 34 is pivoted to its closed position and is forcibly held in that position so long as fluid pressure is maintained in cylinder 41. When devices 40 are operated in the opposite sense, causing piston rods 45 to be retracted, closure member 34 is swung to its fully open position, uncovering aperture 31.

Charger 8 and the compression chamber-defining structure 25 combine to form a rigid assembly which is movable vertically relative to main frame 1 and weigh frame 7. Two vertically acting pressure fluid operated piston-and-cylinder type power devices 48 are provided to move charger 8 and structure 25, the power devices being located each at a different one of two opposite sides of the charger. The cylinders 49 of devices 48 are rigidly supported by brackets 50, FIG. 2, secured to upper transverse members 13 of frame 7. Piston rods 51 of the power devices extend vertically downwardly beside charger 8 and have their free ends rigidly attached to brackets 52 secured to the charger at points immediately above the junction between the charger and structure 25. Recognizing that frame 7 is supported on the floor of well 2 via power devices 17, it will be understood that the combination of charger 8, structure 25 and frame 6 is supported by frame 7 via power devices 48. With frame 7 occupying its uppermost position, power devices 48 are effective to so position the charger and structure 25 that the bottom member 30 of structure 25 is immediately adjacent plates 15 (when piston rods 51 are extended downwardly) and also to so position the charger and structure 25 that structure 25 is spaced above plates 15 by a distance greater that its own height (when piston rods 51 are retracted upwardly). As later described, the charger and structure 25 occupy the lower position during filling and pressing, and the upper position during other operations. The design of the pressing cylinder 24, shaft 23 and ram 22 are such that, when ram 22 is in its lowermost position and the combination of charger 8 and structure 25 is also in its lower position, the ram 22 is slightly below the lower edge of aperture 31.

Press ram 22 is of conventional rectangular form, save that its lower flat face 53, FIG. 1, is interrupted by a plurality of cross grooves 54 which extend at right angles to plates 15 and 18. The upper face of pressure plate 19 is similarly provided with a plurality of cross grooves 20 which are mutually parallel and at right angles to plates 15 and 18.

Referring to FIG. 6, the assembly of parallel plates 18 is such that the ends of each plate 18 overlap and are secured to one of the cross members 5a of the main frame. Each plate 18 includes a rectangular central portion 55, the upper edges 56 of portions 55 all lying in a common horizontal plane which is spaced just above floor 3. At each end of central portion 55, each plate 18 is provided with two upwardly opening notches 57. The upper edges 58 of the end portions of the plate lie in a common plane and can support tread plates 58a.

Plates 15 are supported by two parallel channel members 60 each extending through a different aligned set of the notches 57 in plates 18 so that the central portions 55 of plates 18 project upwardly between members 60. The ends of frame members 60 overlap and are secured respectively to beams 61 which are in turn rigidly supported on bottom cross members 12 of frame 7. For all positions of frame 7, cross members 12 are disposed below the assembly of plates 18, so that the stationary assembly of plates 18 does not interfere with movement of frame 7 and plates 15. In this connection, the beams 61 are parallel to plates 18 and lie outside the assembly of plates. Notches 57 are of such depth as to allow frame members 60 to move with frame 7 to position plates 15 in their raised, operative position, as seen in FIG. 1, and in their lowered position, in which plates 15 lie below the common plane occupied by the upper edges 58 of central portions 55 of the plates 18, as seen in FIG. 6.

Aligned at right angles to plates 15, 18 and supported on floor 3 is a horizontally extending roller conveyor 65, FIGS. 1 and 3. Conveyor 65 is of conventional type, with all of its rollers driven (clockwise, as viewed in FIG. 1) from a suitable power device (not shown) controlled by a foot treadle operated on-off switch. The conveyor is positioned with its input end immediately adjacent the corresponding ends of members 60, and with the rollers 66 disposed to define a supporting plane even with the upper face of pressure plate 19 when, with frame 7 in its lowermost position, the pressure plate is supported by plates 18.

At the side of the press opposite conveyor 65, a fluid pressure operated power device 67 is mounted on floor 3 and frame 1, as by bracket 68 and frame member 69. Power device 67 is of the piston-and-cylinder type, cylinder 70 extending horizontally, and piston rod 71 projecting toward the location of plates 15, 18. A rectangular pusher plate 72 is rigidly secured to the free end of piston rod 71. As best seen in FIG. 8, the upper edge of plate 72 has three projections 73 positioned and dimensioned to engage respectively in the cross grooves 54 of ram 22, and the lower edge of plate 72 is similarly provided with three projections 74 to engage in cross grooves 20 of pressure plate 19.

In order to stabilize press ram 22 during operation of pusher plate 72, an additional fluid pressure operated power device 75 is rigidly mounted on frame 1 above the input end of conveyor 65 and at a vertical position such that, as seen in FIGS. 7-7B, device 75 is aligned horizontally with ram 22 when the latter is in its final position of the pressing cycle. Of the piston and cylinder type, device 75 is disposed with its piston rod 76 projecting horizontally toward ram 22. At its free end, rod 76 rigidly carries a rectangular plate 77 which extends at right angles to the rod and has a flat front face dimensioned for engagement with the total area of the vertical side face 22a, FIG. 1, of the ram. Plate 77 carries two parallel side frame members 78, best seen in FIG. 3, the members 78 projecting rearwardly each from a different end of plate 77. The vertical dimension of plate 77 is substantially larger than the diameter of rod 76, and the rod joins the plate near the upper edge thereof, so that portions of members 78 are below cylinder 79 of power device 75, room thus being provided to accommodate two parallel rollers 80 which are journalled on and extend between frame members 78. Power device 75 can be operated to move the combination of plate 77, members 78 and rollers 80 between the retracted position seen in FIG. 1 and the extended position shown in FIG. 7. In the retracted position, plate 77 is spaced horizontally from the pressing location adequately to allow free movement of the compression chamber defining structure 25. In the extended position, the front face of plate 77 engages side face 22a of the ram, and rollers 80 are located near the ram.

To complete the structure, an upper roller conveyor 81, FIG. 1, is suitably mounted with its input end immediately adjacent power device 75. A plurality of rollers 82 of conveyor 81 are driven (counterclockwise as viewed in FIG. 1) from the same power source (not shown) employed for lower conveyor 65. At its output end, conveyor 81 comprises one or more free rollers 83. Rollers 80, 82 and 83 lie in a common horizontal plane. A conventional strapping guide, illustrated diagrammatically at 84, FIG. 1, lies in a vertical plane passing between the last of driven rollers 82 and the first free roller 83.

OPERATION OF THE APPARATUS TO PRACTICE THE METHOD

In practicing the method of the invention with the apparatus of FIGS. 1-6, the assembly of charger 8 and compression chamber-defining structure 25 is raised, by action of power devices 48, so that bottom member 30 of structure 25 is spaced above plates 15 and 18. Press ram 22 is raised to its uppermost position. Power devices 17 are operated to raise frame 7 to its upper position, so that the upper edges of plates 15 are disposed above the upper edges 56 of support plates 18. Pressure plate 19 is in place, as seen in FIG. 1, with the top edge portions of plates 15 engaged in slots 15a. A first bale board 85, which can be a piece of heavy plywood of rectangular plan conforming to and slightly smaller than the transverse cross section of chamber 25, is placed on pressure plate 19. At this stage, both pusher plate 72 and stabilizer plate 77 are in their retracted positions. Power devices 48 are now operated to lower the charger and structure 25 until member 30 has embraced bale board 85, with the bale board received in the lower end of structure 25. So disposed, board 85 forms an effective bottom closure for the compression chamber defined by structure 25. Power devices 40 are operated to swing member 34 to its closed position and to hold that member closed. Infeed conveyor 21 is operated to supply loose tobacco, or other compressible material to be packed, continuously until the combination of charger 8 and structure 25 has been filled, the amount of material thus supplied being weighed via plates 15 and power devices 17. When the proper amount of material has been delivered and the weighing operation has been completed, power devices 17 are operated to lower frame 7 until, plates 15 having descended below upper edges 56 of plates 18, the pressure plate 19 rests directly on upper edges 56 of the support plates 18.

Pressure fluid is then supplied to press cylinder 24 to drive shaft 23 downwardly through the charger until ram 22 reaches a position just below aperture 31, so that the material in charger 8 and structure 25 is compressed into the chamber defined by structure 25. Operation of the press is then reversed, withdrawing ram 22 upwardly to a location immediately above the lower end of charger 8. Power devices 40 are then operated to swing closure member 34 to fully open position. The mass of tobacco or other material retains its compressed state to such an extent that the top of the mass is below aperture 31, there thus being a substantial free space between ram 22 and the compressed mass. A second essentially rigid flat bale board 86, identical to board 85, is now inserted through aperture 31 and allowed to drop onto the upper surface of the compressed mass. Power devices 40 are then operated to return member 34 to its closed position, and the press ram is again driven downwardly, the extent of such movement being so controlled that not only does the lower face 53 of the ram come into engagement with board 86 but alos the mass of tobacco or the like is placed under some additional compression. This step of the pressing operation is carried out to, in effect, "overcompress" the mass of tobacco or the like, i.e., to reduce the height of the compressed mass below that desired for the finished bale. In the typical case of a bale which is to be 1.1 meters high, this step is carried out to reduce the height of the compressed mass to approximately 0.9 meter.

While ram 22 is retained in engagement with board 86, and the mass of tobacco or the like remains under compression between boards 85 and 86, power devices 48 are operated to raise the combination of charger 8 and structure 25 until the bottom of structure 25 is spaced well above the press ram. Ram 22 is now raised to precisely the bale height desired. Simultaneously, power device 67 is operated to move pusher plate 72 toward the compressed mass, and power device 75 is operated to move the combination of plate 77, frame members 78 and rollers 80 toward ram 22. By suitable control means (not shown), the step of raising the press ram to the desired bale height and the steps of operating power devices 67 and 75 are so timed that pusher plate 72 engages the compressed mass substantially at the time when ram 22 stops at the desired bale height. Due to the inherent resiliency of the compressed mass, the mass tends to expand as the ram 22 is raised. Upward movement of the ram is at a rate such that the ram retreats at least as fast as the compressed mass expands. Accordingly, there is a relatively short time period during which the mass does not urge board 86 against press ram face 53 so strongly as to create a large frictional force between the board and ram face. During this short period of time, pusher plate 72 acts to push the combination of the compressed mass of tobacco or the like and bale boards 85, 86 laterally from beneath the press ram in the manner shown in FIGS. 7 and 7A. Considering FIGS. 7 and 8, it will be noted that projections 73 of plate 72 are slidably engaged in cross grooves 54 and that projections 74 are slidably engaged in cross grooves 20 of pressure plate 19 so that positive engagement of pusher plate 72 and both bale boards 85 and 86 is assured.

As pusher plate 72 applies pressure to the compressed mass and bale boards, the stabilizing structure comprising plate 77 prevents press ram 22 from moving in the direction of travel of plate 72. In this connection, it is to be noted that, at this stage, the press ram would be restrained only by its shaft 23, which is so long as to be laterally yieldable, were it not for engagement of plate 77 with the press ram.

The stroke of power device 67 is such that the power device forces plate 72 substantially completely through the space between ram 22 and pressure plate 19, the position of plate 72 shown in FIG. 7A being a typical limit for travel of the pusher plate. As plate 72 advances, the combination of the compressed mass and bale boards emerges and is engaged between upper rollers 80 and the driven rollers 66 of lower conveyor 65. As soon as lower board 85 is engaged by rollers 66, conveyor 65 acts to positively advance the combination of the compressed mass and bale boards away from the press. When the leading end of the combination advances beyond strapping guide 84, FIG. 1, conveyors 65 and 81 are stopped, and a first strap or band 87, FIG. 7B, is applied to extend over both bale boards and completely around the still-compressed mass. Conveyors 65, 81 are then started again to advance the combination of the compressed mass and bale boards until the midpoint thereof is at the strapping guide, at which time the conveyors are stopped and a second strap or band 87 is applied. The conveyors 65, 81 are then started again, the combination advanced to bring the trailing end near the strapping guide, the conveyors stopped, and the third strap or band 87 applied, the conveyors then being started so that conveyor 65 can operate to deliver the completed bale to an appropriate location, spaced from the press, for further handling.

As soon as the combination of the compressed mass and bale boards has been pushed out of the space between ram 22 and pressure plate 19, power devices 67 and 75 are operated to retract the pusher plate 72 and stabilizing plate 77, respectively, and the press ram is raised, as indicated in FIG. 7B. Thus, even though the bale just formed is still being strapped, the next cycle of the press can commence. Since the time required for the strapping operation is shorter than the cycle time of the press, the press can be operated cycle after cycle without the press cycle time being affected by the strapping operation.