US2038721A - Machine for the production of molded pulp articles - Google Patents

Description

April 28, 1936. H. J. DESMOND MACHINE FOR THE PRODUCTION OF MOLDED PULP ARTICLES Filed Sept '7, 1954 3 Sheets-Sheet l INVENTOR HISTDESMOND.

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April 28, 1936. H. J. DESMOND MACHINE FOR THE PRODUCTION OF MOLDED PULP ARTICLES Filed Sept. 7, 1934 3 Sheets-Sheet 2 INVE NTOQ: H. 3'. 'DESMOND.

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April 28, 1936. H. J. DESMOND MACHINE FOR THE PRODUCTION OF MOLDED PULP ARTICLES Filed Sept. '7, 1934 3 Sheets-Sheet 3 INVENTOIZ:

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Patented Apr. 28, 1936 UNITED STATES Search Room PATENT OFFICE MACHINE FOR THE PRODUCTION OF MOLDED PULP ARTICLES Herbert John Desmond, Waterville, Maine, assignor to Canadian Keyes Fibre Company, Limited, a corporation of Nova Scotia, Canada Application September '7, 1934, Serial No. 743,037 In Canada March 31, 1934 7 Claims.

This invention relates to machines for the production of molded pulp articles such as plates, dishes, bottle packs, egg flats, plaques, sheets of board and the like.

The articles may be made from any kind of wood pulp, or from pulp made from any other suitable fibrous material, for example, cotton, hemp or asbestos, and may for instance, have a consistency of stock, 99 water, to 3% stock, 97% water.

The object of the invention is to provide a machine of relatively simple construction and increased eflficiency and output.

According to the invention a mat of pulp stock is gathered by suction on a reciprocatory forming die which is alternately immersed in a tank of pulp and pressed into engagement with a transfer die to mold the mat to the desired shape. After each stroke of the forming die the transfer die carrier rotates to bring another transfer die into position for cooperation with the forming die and to perform drying operations on the article just formed.

Preferably, the improved machine comprises a number of individual units so that as many different shapes or sizes of articles may be made as there are units in the machine. By means of this arrangement any unit may be started, stopped, or run at any speed within the speed limit of the machine, independently of any other unit of the machine.

The invention consists in the combination and arrangement of parts hereinafter described and more particularly pointed out in the appended claims.

Referring now to the accompanying drawings which illustrate, by way of example, a convenient embodiment of the invention,

Figure 1 is a front elevation of one unit of the machine, and a portion of a second unit,

Figure 2 is a side elevation of Figure 1,

Figures 3 and 4 are diagrammatic side elevations, partially in section, illustrating the operation of the machine.

Figure 5 is a side elevation of the hub of the transfer dies,

Figure 6 is a plan View of Figure 5 partially in section on line 6-6,

Figure 7 is an end elevation of the port box which cooperates with the hub shown in Figures 5 and 6,

Figure 8 is a section on line 8-8 of Figure 7,

Figure 9 is a plan view of the machine, partially in section,

Figure 10 is a side elevation of the main cam of the improved machine, and,

Figure 11 is a detail view showing the timed geans for creating air pressure in the forming In the illustrated form of the invention the frame of the machine comprises a main frame I, a forming die supporting frame 2, uprights .3 and a drive frame 4.

On the frame 2 is supported a stock tank 5, in which is mounted a forming die guide 6, provided with openings 1. Slidingly fitted in the guide 6 is a hollow plunger 8, the upper end of which constitutes the forming die as indicated at 9. The plunger may be provided with a pair of dies 9 as shown in Figure 1. The dies 9 are formed with a multiplicity of small perforations and are of any suitable shape depending on the shape of the articles which it is desired to manufacture, those shown in the drawings being suitable for producing plates.

The stock tank 5 of each unit of the machine is connected to a main stock tank In by means of a pipe II, as shown in Figure 4, the tank l0 being provided with an adjustable weir l2 to maintain the stock in the tank 5 constantly at the required level.

The die plunger 8 is connected to a hollow rod l3 which passes down through a gland l4 and is provided at its lower end with a hollow fitting l5 and is also connected to a piston rod l6, operated by a piston IT in a cylinder l8, associated with a suitable valve cylinder IS.

A vacuum control valve 20 is connected by a flexible hose 2| to a port in the fitting I5 leading to the interior of the rod l3 and thence to the interior of the die plunger 8. The hose 2| is omitted from Figure 1 for clearness of illustration.

The valves in cylinder I9 are operated by any convenient mechanism to admit and exhaust compressed air, or other fluid under pressure, to and from the cylinder l8. This operating mechanism is shown as consisting of a lever 22, rods 23 and 24, and a lever 25 provided with a roller 26 engaging a slot 21 in a cam 28, mounted on a counter shaft 29, journalled in bearings 30 on the drive frame 4.

The vacuum valve 20 may conveniently be operated through a tappet 3| by means of a lever 32, rods 33, 34, and 35, and a lever 36 which is pivoted on a bracket 31 and provided with a roller 38 engaging a cam 39 on the shaft 29.

Above the forming dies 9 are arranged a plurality of transfer dies 40 which revolve intermittently and cooperate in turn with the forming dies 9. Each transfer die 48 has a shape complementary to that of the coacting forming die, and is provided with minute perforations (see Figure 3). The dies 48 are carried by hollow carriers 4| which are rigidly mounted on a hub 42 which is secured to a shaft 43 mounted in bearings 44 carried by brackets 45 bolted to the uprights 3. Coacting with one side of the hub 42 is a stationary port box 46 which may conveniently be made in two halves, bolted together, as indicated in Figures 7 and 8. The box 46 is formed with an annular passage, divided into three compartments, 41 and 48, by means of partitions 49 and 58. Between the passages 41 and 48, and the surface of the box, are formed thirteen ports a to m, the port a opening into the compartment 41 and the remainder into compartment 48. Pipes 52 and 53, leading to a suitable source of vacuum, not shown, communicate with the compartments 41 and 48 respectively. A pipe 54, connected to a source of air pressure, not shown, communicates with a small port 55 which opens at the surface 5|.

The face 5| of the port box contacts with the machined face 56 of the hub 42 which is formed with four axial ports 51 which are arranged to register successively with ports a to m. The ports 51 are L-shaped and communicate at their inner ends with the interior of the hollow die carriers 4|. Smaller ports 51a, adapted to registersuccessively with the pressure port 55, extend The hub 42, with carriers 4| and dies 48, is in-' termittently rotated, for example, by means of a bevel gear 58 keyed to the shaft 43 and meshing with a bevel gear 59 carried by a vertical shaft 68 journalled in bearings 6| and 62. At the top of shaft 68 is a bevel gear 63 meshing with a gear 64 keyed to a short shaft 65 which is mounted in a bearing 66 and furnished with a spur gear 61. The gear 61 meshes with a gear 68 connected to or integral with a disc 69 (see Figure 9). The disc 69 constitutes one element of a friction drive device, and with the gear 68, is rotatably mounted on the counter shaft 29. A friction disc 18 is splined to the shaft 29 and a spring 1| is compressed between the disc 18 and a collar 12 so that the disc 18 is constantly pressed into frictional engagement with the disc 69. The shaft 29 is driven continuously by means of a gear 13 keyed to the shaft and meshing with a smaller gear 14 carried by a main drive shaft 15 mounted in bearings 16. The shaft15 has a gear 14 for the gear 13 of each unit of the machine, but only one is shown in the drawings. The main shaft is driven by any suitable means, a pulley 11 being indicated for this purpose. The hub 42 is held stationary during the greater part of each revolution of the shaft 29 by means of a stop latch 18 pivoted at 19 on a bracket 88 which also carries the bearing 6|. The free end of the latch 18, when in its lowered position, lies in the path of four equally spaced pins 8| carried by a disc 82 which is secured to the hub shaft 43. The latch 18 is raised and lowered by means of a jointed rod 83 guided by a bearing 84 and provided at its upper end with a roller 85 which engages a slot 86 in the main cam 28.

Above the transfer dies is arranged a pair of heating dies 81 of similar construction to the forming dies 9, except in that the perforations may be omitted. The dies 81 are heated by any suitable means, not shown, and are mounted on a. carrier 88 secured to the lower end of a rod 89. The rod 89 is connected to a piston 98 in a cylinder 9| which is associated with a valve cylinder 92, the valve of which is actuated by a centrally pivoted lever 93, a rod 94, and a lever 95, the outer end of which is pivotally connected at the junction of the rods 23 and 24, so that the valve cylinders I9 and 92 are actuated simultaneously.

Within the tubular rod I3 is a smaller tube 96 which, at its upper end, opens into the interior of the plunger 8 and at its lower end communicates with a flexible hose 91 which leads through suitable valve mechanism, to a source of air pressure, not shown.

In the illustrated form of the invention the die carriers 8, 4| and 81 each carry two dies though the invention is not restricted to this arrangement as one die or more than two dies, may be provided on each carrier if desired.

The operation of the machine is as follows: A supply of pulp 98 of the desired consistency is maintained in the tank l8 and consequently a similar level of pulp is constantly maintained automatically in tank 5, the pulp entering the guide 6 through the aperture 1. The initial position of the parts is indicated in Figure 4 in which the die plunger 8 is at the bottom of its stroke and the die carrier 88 is in raised position. The vacuum valve 28 is open and the interior of plunger 8 is under reduced pressure. The shafts 15 and 29 are rotating but as the stop latch 18 is in lowered position the hub 42 and transfer dies 48 remain stationary, this action being permitted by the slipping of the clutch 69, 18. Water is sucked through the perforations in dies 9 and a mat of stock accumulates on these dies as indicated at 99, the mat consisting for instance, of to stock. After a suitable time interval, during which the mat 99 has acquired the necessary consistency and thickness, the roller 26 is raised by cam slot 21 and levers 25, 22, 95, 93 and links 24, 23, and 94 are actuated to cause admission of fluid to the bottom and top of cylinders |8 and 9| respectively. The forming dies 9 are therefore raised and the heating dies 81 are simultaneously lowered. The mat of pulp 99 is pressed into the dies 48 and caused to assume the shape of the dies as indicated at A, (Figure 3). The port 51 in hub 42, corresponding to the lowermost pair of dies 48 is in registry with port a in box 46 so that the die carrier 4| is under reduced pressure and moisture is therefore sucked from both sides of the articles A.

Then roller 38 falls into the depression in cam 39 and the linkage 36, 35, 34, 33, 32 is actuated to permit vacuum valve 28 to close. At the same instant a momentary blast of air under pressure is admitted to the die plunger 8 by way of hose 91 and tube 96, to permit the dies 9 to descend without removing the articles A from dies 48, in which the vacuum is maintained. The articles A are therefore transferred to the dies 48. This air blast preferably starts as soon as possible after the pressing dies 9 have been raised, so that the molded pulp is subjected to air pressure from below and suction from above, and drying is thereby expedited. The cam 21 now initiates a reverse movement of the dies 9 and 81 to lower and raise them respectively. As soon as the dies 9 are again immersed in the pulp in tank 5 the vacuum valve 28 is reopened to cause the formation of another mat 99.

Cam slot 86 now momentarily raises the stop latch 18 through the rod 83 to disengage the latch from pin 8|, and the hub 42, with its associated dies, is permitted to rotatein the direction of the arrow X in Figure 4. As soon as the pin 8| has been released, the latch is again lowered, so that it engages the next pin 8| and arrests the hub 42, after it has rotated a quarter of a revolution.

The formed articles are thus moved to position A where they remain drying by evaporation and suction, while the above described sequence of operations is repeated on the next pair of dies 40. During the movement from position A to A the port 51 passes successively over ports 17, c, and d and comes to rest in registry with port e, so that the vacuum is maintained in the die carrier 4| and the articles continue to adhere to dies 40.

When the latch 18 is again raised the article is moved on to position A the hub port 51 passing over box ports f, g, and h and coming to rest over port 1. In this position the article is engaged by the heated die 81, and the drying process is continued, partly by heat from die 81 and partly by suction due to the reduced pressure in the die carrier 4|.

When the latch 18 is again lifted the articles pass on to position A the port 57 passing over box ports 7', k, and Z and coming to rest in register with port m. The articles therefore remain in position A still subject to the drying action of the suction in the carrier ll, while a further article is being molded at position A.

When the latch 18 is next raised the dies carrying articles A resume their movement, and the port 51 moves out of register with port m thereby removing the suction from the article A The port 51 then moves over the small port 55 and a blast of air is admitted to the die carrier so that the finished article A is blown from the dies 40, as indicated at A, on to a conveyor or into a bin. The now empty die continues its movement until it comes again to position A where port 51 again registers with port a. For a moment, before the mat 99 is pressed against the dies at position A, the port a is open to atmospheric pressure through the perforations in the dies 40, but the partitions 49 and 50 prevent reduction of pressure in compartment 40 of the port box.

The timed means for creating air pressure in the forming die is shown in Fig. 11 wherein a valve I02 is mounted on the machine frame by means of a bracket I03 and in position to be operated by a screw IOI inserted in the lever 32 which operates the tappet 3| of the vacuum valve 20. When the linkage 36, 35, 34, 33, 32, is actuated as previously described to permit the vacuum valve 20 to close, the screw IUI in lever 32 comes in contact with the stem of the air valve I02, causing it to open and allowing a blast of air to pass from a suitable supply (not shown) through the pipe I04 and into the forming die carrier through the hose 9! and the pipe 95. An air pressure is thus created on one side of the article at the same time that a vacuum is created on the other side of the article.

It will be understood that the foregoing description is given by way of example only, and that many modifications within the scope of the appended claims may be resorted to without departing from the invention.

What I claim is:--

1. A pulp molding machine comprising a revolving series of transfer dies, means for revolving said transfer dies step by step, a reciprocating forming die, a tank containing pulp in which the forming die is immersed when at the bottom of its stroke, a heating die, means for simultaneously moving said forming and heating dies into and out of engagement with opposite transfer dies, means for revolving said transfer dies through one step after each reciprocation of the forming and heating dies, means for creating suction within the forming die during its upward stroke and its immersion in the pulp, means for creating suction in the transfer dies during the greater portion of their revolution, and means for creating a momentary period of air pressure in each transfer die in turn during the last step of each revolutionary movement.

2. A pulp molding machine comprising a frame, a shaft mounted in said frame, a hub carried by said shaft, a plurality of hollow die carriers on said hub, perforated dies on said carriers, ports in said hub opening into said carriers, a stationary box having ports coacting with the ports in the hub, yielding means constantly tending to rot-ate said shaft, a disc on said shaft, projections on said disc, a pivoted latch coacting with said projections, means for intermittently moving said latch to permit the shaft to rotate until the next projection engages the latch, a reciprocated perforated forming die, a tank, means for moving said forming die alternately into said tank and into engagement with said transfer dies in turn, and means for creating suction in said transfer and forming dies.

3. A pulp-molding machine comprising a tank, means for maintaining pulp at a desired level in said tank, a. perforated forming die mounted to reciprocate within said tank and to pass beneath the pulp level therein, means for creating a suction beneath said die when it is below the pulp level to form a mat of pulp stock thereon, a revolving series of complementary perforated transfer dies above said tank, means for imparting an intermittent movement to said transfer dies to successively bring them to a position above said forming die, means for intermittently raising said forming die to cause the mat thereon to be pressed against a transfer die when one of said transfer dies has been moved to a position above the forming die, means for causing the mat of pulp on the forming die to be transferred to the transfer die, means for creating suction within said transfer die to maintain the pulp mat thereon, a reciprocating heated die adapted to cooperate with the transfer dies successively after they have received a mat of pulp from the forming die, and means for successively discharging the formed pulp from the transfer dies after they pass said heated die.

4. A pulp-molding machine comprising a tank, means for maintaining pulp at a desired level in said tank, a perforated forming die mounted to reciprocate within said tank and to pass beneath the pulp level therein, means for creating a suction beneath said die when it is below the pulp level to form a mat of pulp stock thereon, a revolving series of complementary perforated transfer dies above said tank, means for imparting an intermittent movement to said transfer dies to successively bring them to a position above said forming die, means for intermittently raising said forming die, to cause the mat thereon to be pressed against a transfer die when one of said transfer dies has been moved to a position above the forming die, means for causing the mat of pulp on the forming die to be transferred to the transfer die, means for creating suction within said transfer die to maintain the pulp mat thereon, a reciprocating heated die substantially in alignment with the forming die and means for simultaneously moving the forming die and the heated die towards opposite transfer dies.

5. A pulp-molding machine comprising a tank, means for maintaining pulp at a desired level in said tank, a perforated forming die immersible in the pulp in said tank, means for creating suction beneath said die to form a mat of pulp stock thereon, a revolving series of transfer dies, a continuously-driven shaft, a friction clutch driven by said shaft, gearing driven through said friction clutch for causing a revolving movement to be imparted to said transfer dies, a latch to arrest the movement of the transfer dies to cause said clutch to slip, means for intermittently operating said latch whereby an intermittent movement will be imparted to said dies to bring them successively into a position for cooperation with said forming die, means for intermittently raising said forming die to cause the mat thereon to be pressed against the cooperating transfer die, and means for creating suction within said transfer dies.

6. A pulp-forming machine comprising a revolving series of transfer dies, means for revolving said transfer dies step by step, a forming die, a tank adapted to contain pulp in which the forming die is immersed, a heating die, means for simultaneously moving said forming and heating dies into and out of engagement with the transfer dies, means for revolving said transfer dies after the forming and heating dies have been brought into engagement therewith, means for creating suction within the forming die when it is immersed in the pulp in the tank to cause a mat of pulp to be formed thereon, means for creating suction in the transfer dies during a portion of their revolution, and means for creating a momentary period of air pressure in each transfer die to discharge the molded pulp therefrom after the heating die has been moved out of engagement with said transfer die.

'7. A pulp-molding machine comprising a tank, means for maintaining pulp at a desired level in said tank, a perforated forming die immersible in said pulp, means for creating suction beneath said die to form a mat of pulp stock thereon, a. hub shaft mounted above said tank, a hub member rotatable with said shaft, transfer dies carried by said hub member, a continuously-driven shaft, a friction clutch driven from said shaft, gearing driven through said clutch and operatively connected to said hub shaft to rotate the same, means for intermittently rendering said friction clutch inoperative to drive said gearing whereby an intermittent movement is imparted to said transfer dies and said transfer dies successively are brought into position for cooperation with said forming die, means for intermittently raising said forming die to cause the mat thereon to be pressed against the cooperating transfer die, and means for creating suction within said transfer dies.

HERBERT JOHN DESMOND.

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