US2961042A - Pulp molding apparatus - Google Patents

Description

H. A. WOLTER PULP MOLDING APPARATUS 3 Sheets-Sheet 1 Locu ATTORNEY Nov. 22, 1960 Filed may 10, 1957 Nov. 22, 1960 H. A. woLTER PULP MOLDING APPARATUS 3 Sheets-SheeiI 2 Filed May l0, 1957 INVENTOR am Locus ATTORNEY NOV. 22, 1950 H. A. woLTER 2,961,042

PULP MOLDING APPARATUS Filed May l0, 1957 3 Sheets-Sheet 3 INVENTOR @Q2/@ym ATTORNEY Unite States atent O PULP MLDNG APPARATUS Harry A. Wolter, Ain-on, Ohio, assignor to Diamond National Corporation, a corporation of Delaware Filed May 10, 1957, Ser. No. 658,410

8 Claims. (Cl. 162-394) This invention relates to pulp molding apparatus, and more particularly to an improvement in apparatus for successively molding pulp articles.

In the manufacture of molded pulp articles by the usual process of suction molding the articles from a Water slurry of pulp fibers, it has been customary to employ a rotary carrier having a plurality of foraminous forming dies mounted on its periphery, which dies are subjected to suction internally as they are advanced successively through a vat containing the slurry during rotation of the carrier. This action causes layers of wet pulp bers to be extracted from the slurry and deposited on the molds, thereby forming initially molded articles, known as preforms. In order to extract some of the excess moisture from the wet pulp preforms, the suction applied to the molds is continued as the molds emerge from the slurry and advance successively `upward thereabove during continued rotation of the mold carrier. At a predetermined point above the slurry, a transfer device, which is usually of the rotary type also, suc- Iessively removes the preforms from the molds and transfers them to a dryer.

The above-described rotary type multiple die molding apparatus is particularly suitable for high speed production of large quantities of relatively non-complex, small, low unit cost molded pulp products, such as pie plates and egg cartons. However, the high initial costs required for purchase and installation of this equipment represent such a large investment to be amortized, that only such large. quantity production items can be manu- `factured economically. One of the principal reasons for this situation is the high cost of the individual molding dies. In order to provide for the manufacture of smaller quantities and special orders for items requiring larger or more complex molding dies, a need has existed for less expensive apparatus combining simplicity with efficiency, and preferably this apparatus should have only a single cooperating pair of dies. Although apparatus of this general type has been known in the past, none of the prior art apparatus has been entirely satisfactory.

An object of this invention is to provide new and improved pulp molding apparatus.

Another object of the invention is to provide a more eiiicient, simplified, and inexpensive pulp molding ,apparatus of the type embodying only a single p air of cooperating dies.

Still another object of the invention is to provide a new and improved mechanical movement for a single pair of cooperating dies in a pulp molding machine.

Other objects and the nature and advantages of the instant invention will be apparent from the following description, taken in conjunction with the accompanying drawings, wherein:

Fig. l is a fragmentary side elevation view of pulp molding apparatus embodying the invention, shown in one operating position of a molding operation;

Fig. 2 is a corresponding view of the apparatus illustrated in Fig. l, but showing the apparatus in another operating position;

Fig. 3 is a fragmentary side elevation view of pulp molding apparatus forming a second embodiment of the invention, shown in one operating position of a molding operation; t

Fig. 4 is a view corresponding with that of Fig. 3, but showing the apparatus in another operating position; and

Fig. 5 is a plan view of the apparatus corresponding with Fig. 3.

Molding apparatus embodying the invention features a simplied structural organization and an improved type of simple mechanical movement, in comparison with that of the complex machines generally employed lheretofore. In the embodiment of the invention illus,- trated in Figs. 1 and 2, a molding die 19 having a forarninous forming face 11 is vertically reciprocable into and out of a vat 12 containing pulp slurry. The die 19 is secured to the lower end of a hollow vertical shaft 14, which is connected to a source of suction (not shown) for the purpose of applying suction to the interior of the die 1t) during its immersion in the pulp slurry contained in the vat 12. Any suitable means may be employed for imparting vertical reciprocatory motion to the shaft 14, and such means is so well known that it is considered unnecessary to illustrate and describe it in detail. The resultant reciprocatory motion imparted to the die 10 moves it alternately between a molding position immersed in the pulp slurry, shown in Fig. 1, and a Vcompressing position elevated above the slurry, depicted in Fig. 2.

A particularly important feature of the invention is the fact that the motion of the die 16 is perfectly linear, being reciprocated in a straight line between its immersed position and its elevated position. Another important feature of the invention is the fact that the die 1t) is held facing its immersed position at all times, without Ytilting or turning during its reciprocatory motion. Thus, the forming face 11 of the die 1i) is always disposed horizontally and facing downwardly, although some slight deviation may be permissible. This arrangement insures a uniform depth of deposition of the pulp fibers from the slurry on all portions of the forming face of the molding die, and makes it possible to mold deep articles with greater success than was heretofore possible. If a molding die were moved into theslurry with an arcuate movement, or if the die entered sideways, a washing eiect would inevitably occur on certain portions of the die, thereby resulting in a lack of uniformity in the deposition of pulp fibers thereon. This undesirable effect is completely avoided in apparatus em bodying the invention by having the molding die enter the slurry in a straight line movement While facing its ultimate immersed position.

When the molding die 10 is in its elevated position, it is brought into registration with a cooperating compression and transfer die 16 having a foraminous forming face 17 designed to mate with the forming face 11 of the die 10. The die 16 is carried rigidly secured at one end of a swingable arm 1S having its other end mounted at a pivot point 20. Suitable means (not shown) is provided for swinging the arm 18 back and forth, thereby to oscillate the die 16 through a circular arc of approximately centered on the pivot point 20. Of course, the 0scillatory movement of the die 16 must be synchronized with the reciprocatory movement of the die 1i). In this manner, the die 16 is moved to its position registering with the die 10, whereupon these dies cooperate to compress between them the wet pulp preform which was de-A p csited on the die li during its immersion in the vat 12. This compression action assists in completing the molding of the pulp article, and at the same time more excess moisture is expressed therefrom. Following this corn? A Y Y 3 pression action the pulp article is transferred from the die to the die 16. This may be accomplished by a blowing or a sucking actionQ The suction which has been applied to the die 10 is shut oli, and suction is then applied to the ldie 16. A flexible hose 22 connects the die 16.to Athe .previously mentioned source .of suction, Vand suitable automatic controls for the suction are synchronized with the movement of the two dies.- l

At the other eXtreme limit of its oscillatory movement, the die 16 overhangs an end portion of an endless, horizontally disposed conveyor belt 26, arranged to carry the molded pulp articles toward nal drying and nishing apparatus (not shown). This end of the conveyor belt 26 is horizontally,reciprocable, so that it may be shifted out of the way of the die 16'when this die is being Aoscillated through its arcuate path toward the die 10. The reciprocatory movement of this end of the belt 26 .enables it to be positioned beneath the die 16 in the proper position to receive a molded pulp article therefrom, as illustrated in Fig. 1. It should'be observed at thisrtime that the die 16 becomes completely inverted as the result of its oscillatory motion through the 180 arcin moving away from the die 10, so that the pulp article lands on its dat bottom side as it drops onto the A belt 26 when the suction on the die 16 is stopped. Furthermore, when the belt 26 is in its receiving position beneath the die 16, it is spaced relatively closely thereto,

so that the pulparticle falls only a short distance from ,the die to the belt, thereby avoiding damage to the article whilesit isV still somewhatmoist and hence is still quite pliable and fragile. Under some circumstances, it may be desirable to applyV a blast of Vcompressed air through the `hose 22 to blow the pulp article from the die 16 Vonto the belt 26.

, jHorizontal reciprocation ofthe end of the belt 26 may `be accomplished by advancing the belt around a Xed pulley 27 and thence around a pair of horizontally shiftable pulleys 28 and 29, thereby forming a pair of parallel loops 30and 32 in the belt 26. By shifting the pulleys 28 and 29 in unison between their positions shown inY Fig. '1 and their positions shown in Fig. 2, the loop 32 is reciprocatedrbetween its receiving position beneath the die 16 and its clearing position out of the path of this die, While the loop 30 provides the necessary adjustment of the slack to allow this movement of the belt 26. It is vevident that suitable automatic controls may be provided for shifting the end of the belt 26 in proper synchronization with the movement of the die 16. Y f

TheY second embodiment of the invention illustrated in Figs. 3 and 4 is generally Vsimilar to that of the abovedescribed rst embodiment, but in the second embodiment an arrangement is provided for shortening the path traveled by the transfer die, and the adjacent end of the conveyor belt may be shifted in a diierent manner. A molding die 110 having a forming face 111 is vertically reciprocable into and out of a vat 112 containing pulp slurry.v4 The die 110 is mounted on the lower end Yof a hollow vertical shaft 114, which may be reciprocated vertically by 'any suitable means to move the die V110 between an immersed molding position, shown in Fig. 3,

and an elevated compressing position, depicted in Fig., 4.

As, in the case'of the iirst described embodiment of the Iinvention, the die 110 is reciprocated in a perfectly straight line motion, without tilting or turning, and while held with its forming face 111 facing its immersed position at all times. Y

VA cooperating compression and transfer `die 116 is priovlded with a foraminous face 117 designed to mate with tl1e forming face 111v of the dier110. The die 116 is oscillated into mating registration with the die 110, when this die is inits elevated position, by means of an oscillating mechanism including a swingable arm 118 having one end thereof secured at a pivot point V120. The Vdie 116 is also provided with a pair of rigid parallel arms 1.2717, 0f Which Only one appears in the drawings, Vfor securing this die pivotally to the other end of the swingable arm 118. A flexible hose 122 connects the die 116 to a source of suction, in the same manner as the hose 22 described in the tirst embodiment of the invention. A pair of cam rollers 123, of which only one is shown in Figs. 3 and 4, mounted,k on opposite sides of the die 116 ride in an arcuate cam track designed to turn the die 116 about its transverse axis during its oscillatory movement. The cam rollers 123 serve as a pivot point for this turning motion, and the die 116 becomes completely inverted as it swings between the extreme limits of its oscillatory motion. It should be noted that the forming face 117 of the die 116 is disposedY horizontally at both of the extreme limits of its swing. During its inversion, the die 116 travels through a circular arc of more than 90 but of considerably less than 180 with respect to the pivot point 120, due to its simultaneous turning about the pivot point provided by the cam rollers 123. This mechanical movement advantageously facilitates a more compact arrangement of the entire pulp molding machine.

An adjacent end portion of an endless conveyor belt 126 is disposed horizontally and arranged to receive molded pulp articles, dropped or blown from the die 116, to carry these articles to the final drying and nishing apparatus. Y Thisend of the belt 126 passes around a movable pulley Y127 and over a pair of superposed fixed pulleys 12S and 129, thereby forming a swingable end loop 130 in the belt 126. By swinging the pulley 127 through a short circular arc centered on the pulley 129, the loop 130 may be shifted back and forth between its horizontal position aligned with the rest of the belt 126, shown in Fig. 3, and its inclined position, shown in Fig. 4, wherein it has been dropped away from the path of the die 116. By this arrangement the successively produced molded pulp articles fall only a `short distance from the die 116 to the belt 126.Y

It is evident that the two systems described in the two embodiments for temporarily moving VVthe adjacent end of the conveyor belt out of the path of t-he transfer die are interchangeable, and that -any other suitable system may be employed for this purpose. For example, instead of having a shiftable end portion for a relatively stationary conveyor belt as herein described, an entirely separate shiftable table or conveyor could be employed conjunction with an entirely relatively stationary conveyor belt. Furthermore, other types of transfer mechanisms, such as chutes, roller conveyors, and the like, may sometimesV be substituted for the endless belt conveyor described herein.

Although the invention has been illustrated and described with particular reference to only a single pair of cooperating dies, it is to be understood that each of these dies may be of the multiple type. That is, a plurality of individual dies may be mounted side by side for movement as a group on a single die platen.

It will be obvious to those skilled in the art that various changes may be made without departing Yfrom the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is.:

. 1. Vliulp molding'apparatus, comprising a molding die having a foraminous forming face designed to form pulp articles by deposition of pulp. fibers from a slurry thereof, means for vertically reciprocating the die in a straight line between a molding position immersed in pulp slurry and a compressing position elevated above the slurry, said forming face of the die'being disposed horizontally and'held facing downwardly toward its immersed position vduring itsV entirerecprocatory movement, an oscillative and invertible transfer die mounted adjacent to the compressing positionof the molding die, said transfer dieV having a face designed to mate with the forming face of the molding die, and meansfor Yoscillating the transfer die and inverting it as it moves in a circular arc between a discharge position spaced `away from the molding die and a compressing position in which it is in mating registration with the molding die, said transfer die becoming completely inverted as it oscillates.

2. Pulp molding apparatus comprising a single molding die having a foraminous forming face designed to form pulp articles by deposition of pulp fibers from a slurry thereof, means for vertically reciprocating the die in a straight yline between a molding position immersed in pulp slurry and a compressing position elevated above the slurry, said forming face of the die being disposed horizontally and held facing downwardly toward its immersed position during its entire reciprocatory movement, a single oscillative and invertible transfer die having a face designed to mate with the forming face of the molding die, `and .an oscillating mechanism including a swingable arm having one end mounted at a pivot point `and joined at its other end to the transfer die for osc-illating the transfer die in a circular arc centered on said -pivot point, said transfer die becoming completely inverted as it oscillates between a discharge position overhanging a discharge conveyor and a compressing position in which it is in mating registration with the molding die when the molding die is elevated.

3. The apparatus defined by claim 2 in which the transfer die is rigidly joined to said other end of said swingable arm, and the die oscillates through a circular arc of approximately 180 centered on the pivot point at said one end about which the other end of the swingable arm is mounted.

4. Pulp molding apparatus comprising a molding die having a foraminous forming face designed to form pulp articles by deposition of pulp fibers from a slurry thereof, means for vertically reciprocating the die in a substantially straight line between a molding position immersed in pulp slurry and a compression position elevated above the slurry, said forming face of the die being disposed horizontally and held facing downwardly toward its immersed molding position during its entire reciprocatory movement, a transfer die mounted oscillatively and invertibly adjacent to the elevated compressing portion of the molding die, an oscillating mechanism including an arm swingable about a pivot point at one end thereof land joined pivotally at its other end to the transfer die whereby the arm oscillates the transfer die in a circular arc centered on said pivot point between a discharge position spaced away from the molding die and a compressing position in which it is in mating registration with the molding die, and means for turning the transfer die as it is oscillated by the arm to invert said die completely as it oscillates through considerably less than 180 of the circular arc.

5. The apparatus defined by claim 4 in which the turning means includes a pair of cam rollers mounted on opposite sides of the transfer die, and a pair of arcuate 5 cam tracks cooperate with said rollers to invert said die completely as it oscillates through considerably less than ofthe circular arc.

6, Pulp molding apparatus comprising a molding die having a foraminous forming face designed to form pulp articles by deposition of pulp fibers from a slurry thereof, means for vertically reciprocating the die in a substantially straight line between a molding position immersed in pulp slurry and a compressing position elevated above the slurry, said forming face of the die being held disposed horizontally facing downwardly toward its immersed molding position during its entire reciprocatory movement, a transfer die mounted oscillatively and invertibly adjacent to the elevated compressing position of the molding die, an oscillating arm joined at one end thereof to the transfer die and swingable about a fixed pivot point at the other end of the arm for oscillating the transfer die in a circular arc centered on said pivot point between a compressing position wherein it is in mating registration with the rno-lding die and a discharge position spaced away from the molding die, said transfer die being disposed horizontally at opposite limits of its oscillating movement in its compression position and in its discharge position, and an endless movable belt discharge conveyor disposed generally horizontally adjacent to the discharge position of the transfer die, the adjacent end portion of the conveyor being movable between a receiving position directly beneath and spaced closely to the transfer die when the die is in its discharge position and a clearance position wherein the movable end of the conveyor allows clearance for the oscillating movement of said die.

7. The apparatus defined by claim 6 in which the movable end portion of the horizontal endless movable belt discharge conveyor is shiftable horizontally between its receiving position and its clearance position.

8. The apparatus defined by claim 6 in which the movable end portion of the horizontal endless movable belt discharge conveyor is mounted pivotally for swinging movement downwardly to its clearance position and upwardly to its receiving position, said end portion being in alignment with the main portion of the conveyor when said end is in its receiving position.

References Cited in the file of this patent UNITED STATES PATENTS 1,158,634 Chaplin Nov. 2, 1915 1,203,197 Hogue Oct. 31, 1916 1,397,375 Grunwald Nov. 15, 1921 1,880,458 Morris Oct. 4, 1932 2,225,134 Skolnik Dec. 17, 1940 2,628,540 Randall Feb. 17, 1953 FOREIGN PATENTS 655,944 Great Britain Aug. 8, 1951

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