USRE19524E - Means for forming plastic articles - Google Patents

Description

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, MEANS FOR FORI'ING PLASTIC ARTICLES l Original Filed Aprjil 2, 1927 2 Sheets-Sheet 2 f8 m :'7\E

76 I Y /5 :D i V wom/kot fe:- (74 j Louis WHoZLeZ, s@ uw www( Gramm,

Reissued Apr. 9, 1935 UNITED]v ,Sfija'ilzsl .PATENT OFFICE The Richardson Company, Lockland,

corporation of Ohio Ohio, a

Original No. 1,652,940, dated December 13, 1927, Serial No. 180,530, April 2, 1927. Application for reissue December 13 Claims.

Cross reference is made to applicants copending application, Serial Number 66,312, led Nov. 2, 1925, later granted his United States Patent #1,652,991, Dec. 13, 1927, which contains some features of construction of the present application. No claim is made herein to any invention claimed in said earlier application.

This invention relates to a molding press for forming hollow articles from plastic composition and has particular reference to a press construction possessing special utility for the manufacture of electrical storage battery boxes from plastic compositions of the kind.V that set and harden by cooling as distinguished from those compositions which are hardened or vulcanized by heat; at the same time the press construction being adaptable for utilizing a steam circulating system in connection withv the mold chamber and the core to provide for making hollow rubber articles such as battery boxes by pressing and vulcanization.

To that end a primary object of the invention Vis to provide a novel construction and organization of parts, in a pressof the hydraulic type, whereby a battery box or equivalent article c an be made economically and rapidly from a suitable acid-proof plastic'composition placed in a single mass in the mold and having suicient plasticity toI permit the box or article-to be formed by the closing of theI mold and a suiiicientl set or hardening given to the formed box or article by cooling or chilling the same in the mold before the removal of the completed article.

Another object of the, invention is to provide a novel mold construction and novel means for actuating and controlling the mold whereby the workmen can with great facility and with a minimum loss of time, place a mass of the plastic composition in positionl on the core of the mold, close the Vmold and form the article, open the mold and remove the article and repeat, without tearing down the mold or'otherwise interfering with a consecutive operation of the press so that a large production can be obtained on oneor a battery of such presses. A

With these and other objects in View the invention consistsin the novel construction. and arrangement of parts hereinafter more fully described, illustrated and claimed, and while the invention necessarilyfis' susceptibleof a wide range of modification' without departing from the `spirit or scope of the invention, a preferred vand practical embodiment thereof is shown in l the drawings, in whichz'- v y Fig. 1 is ay front elevation of a `cold vmolding e, 1934, serial No. '156,375

(c1. 1sf-19) press embodying the present invention and showing the mold parts separated, the mold suspending rod having reached its lower limit of travel, but the lower platenhaving a short distance further to travel before completing its downward movement.

Fig. 2 is a. side elevation of the machine with the mold parts in their closed position, said mold parts being shown in section.

Fig. 3 is a detailview of the mold parts after the mold suspending rod has reached its lower limit of travel and the mold has passed completely out of the mold casing or'chamber.

Fig. 4 is a detail view similar to Fig. 3 illustrating the relative position of the mold parts when both the mold suspending rod and the lower platen have fully completed their downward strokes, and the mold has been opened to remove the finished article.

Fig. 5 is a bottom plan view of the mold. proper.

Like reference characters designate correspending parts throughout the several gures of the drawings.

In carrying forward the present invention a characteristic feature thereof is to employ a lower power unit, consisting of the 'ram and its cylinder entirely separate and disconnected from the power unit at the upper part of the press, both of said power units' being hydraulically operated in order to facilitate the carrying out of the various operations in the manner herein particularly referred to.

Primarily the invention comprises, in its general organization what may be termed a lower power unit consisting of an ordinary hydraulic ram, and an upper power `unit which includes mold suspending means for operating the mole. proper which is composed of an articulated group or assembly of mold lining plates. These features of the press construction are operable in the same way regardless .of whether the press is worked as a cold press for (mick,A setting plastic compositions, or is a hot press for vulcanizing rubber articles, but for convenience in describe- .ing theperformance of the press in making a battery box or analogous hollow article the detailed description will be based on the preferable example of employing a cold water circulating system for 'chilling the press Darts.v

The mechanism for` closing the moldand applying pressure thereto may be of various' forms but in thepreferred form illustrated consists of a hydraulic press consisting of a cylinder I which constitutes the base of the machine, a press head.

' plates 8 and side 2 spaced from the cylinder by rods 3, a ram 4 mounted in the cylinder I and carrying a lower platen 5 opposed to the press head.

Below the head 2 of the press is rigidly mounted a mold casing or chamber 6 provided with one or more mold cavities 6a extending through the chamber and having tapered walls so that the openings on the lower side are larger than those on the upper side. In the form'shown, one of suchV cavities is present. The mold casing or chamber 6 is` preferably of a jacketed construc-l tion and provided with suitable'connecting cooling chambers or tunnels 6b having cold water inlet and outlet pipe connections 6c and 6d respectively whereby a cooling fluid may be introduced into the jacket ofv the mold casing or chamber to facilitate the quick setting or partial setting of the box or other article in order that it may be discharged from the mold with facility and without damage thereto.

The' mold consists of a top plate 1,two end plates 8, and two sideplates 9, so fitted together that they form a box open on the lower side only and of tapered or equivalent formation outside swothat the mold fits tightly in the mold cavity Ba of the mold chamber. The p1ates'1, 8 and 9 are provided with'surfaces suitable for molding the article in the desired configuration and mat7 be changed at will and others substituted therefor. To this end the top plate 1 is provided with a threaded socket 1a for attachment to a correspondingly threaded mold suspending-rod Ill connected to piston Illa operating in cylinder IIlb. The said topv plate 1 is in effect really the bottom plate of the mold, though it occupies the topmost position in the mold structure because of the fact that the articulated mold proper is suspended and controlled from the suspending rod III. Furthermore, the said top plate 1 may be and preferably is provided with concave rebates 1b around its upper edges, and the end plates 5, are each provided with corresponding convex shoulders 8a and 9a, whereby said end and side plates are loosely suspended from the top plate andare free to swing laterally except when the mold assembly is seated in themold cavity 6a. This articulation of the mold plate 1 is plainly shown in Figs. 2, 3 and 4 of the drawings and provides the mold proper which freely slides in and out of the mold casing or chamber 6 during the operation of the press.

All of the mold plates may be smooth surfaced or, as shown, provided with raised panels 8c and 9c which impart a paneled appearance to the molded article and-aiso act as dowels to prevent premature relative motion between the mold .and molded article.

Where an article such as abattery container is to be provided with integral handles at the ends, the plates 8 are made of such configuration as to provide extensions of the main cavity for this purpose. Y

For forming the interior of the article, I provide one or'more cores rigidly mounted on the lower platen 5 and provided with cooling means. where such an article is to'be a multiple celled article I provide a suitable number of such cores H, three being shown in the drawings. These cores are for convenience made separately and mounted upon a bottom plate I2 designated to cooperatewith the mold plates to form a completely yclosed cavity when assembled. Each core is provided with ashank I Ia which is held in a corresponding opening Iza. in the bottom plate.

the Shanks Ila into the plate which shrinksthereabout. holding the cores permanently. Each core is provided with cooling cavities IIb and suitable connections a: to a cold water line y are provided by flexible or sliding connections.

Another featureof the invention resides in providing"mear1's` for temporarily holding the liner plates locked so that they cannot be swung free from the article molded therein when the mold assembly is moved downwardly out of the mold E. As will be observed from Fig. 5, the side plates 9 are provided 'with the flange I4 extending along the lower edge of the plates, and said flanges being formed at their ends with the L-shaped hook portions I5 which overlap the end plates 8 so that the latter cannot swing outwardly when the side plates 9 are in place. Secured to the flange I6 of the end plates B, by means of the pivots I1,. are the latch members I8 which are provided at their ends with the keeper hooks I9 which hook over the corners.

will now be made to the method of operation and in that connection'it will now have been understood that the various mold parts are cooled by the cold water circulating system and the'ram 4 is at its lowermost position and the mold suspending rod Ill lifted so as to draw thearticulated mold proper or mold lining plates into the mold casing or chamber, ready to receive the mass or charge of plastic composition when the cores are moved upwardly therein by the raising of the ram. When the parts are so positioned, that is, with the ram lowered and the core or cores in the lowermost position, the plastic composition, which previously has been prepared-and weighed for approximately the right quantity, is placed on top of the cores so that the same will be carried directly into the mold proper when the cores are lifted. Hydraulic pressure is now admitted to the ram cylinder with the result of raising the cores and carrying therewith the mass ofv composition which is carried by the cores into the mold proper and caused to flow to the cores and inner surfaces of the mold lining plates with the result ofl shaping the box or equivalent article as may be plainly seen from Fig. 2 of the drawings.

The cold water circulating about the jacket of the mold casing or chamber and throughout the interior of the cores causes the quick setting or partial hardening of the formed article so that the same can be removed from the mold casing and mold proper.

That is accomplished by first releasing the fluid pressure from the lower ram cylinder and from beneath the piston Illa and then applying hydraulic pressure to the upper end of the piston IIla in the cylinder Illb. The effect of relieving the pressure under the ram and applying pressure above the piston Ia is to cause both the ram and the mold to travel downwardly together until the mold with the core therein are completely out of the mold chamber as shown in Fig. 3, the ram, however, being free, from the start downward, to drop by gravity.

By the time the suspended mold reaches its downward limit and is eased from the lateral 5 pressure of its'tight fit in the mold core or chamber, the' cores Il will drop by gravity out of the moldedarticle as the ram continues its down- '.ward gravitating movement until stopped by the "rani cap engaging the top of the cylinder I. l This, the entire downward movement of vthe core and ram is merely a retreating movement effected by gravity and without sticking.

The mold plates are held together by the latches IB the article will not be accidentally l dropped or released from the mold, but when the latches have been moved to the position shown in Fig. 4 the plates are released ,and the side and end plates of the mold assembly can then be swung suflciently outward to permit article is held in the mold due to the mold plates retaining their closed position after leaving the mold chamber 6a, the separation of the cores from the interior of the formed article is effected merely bythe relative differential downward movement) of the mold parts carried by the suspending rod I0 and the ram from beneath which pressure has been relieved by the opening of the valved exhaust outlet.

When'it is desired to repeat the operationfor 4forming the article, the mold plates 8 and 9 are locked together by the latches II8 and the mold assembly is drawn up by putting fluid-pressure beneath into the chamber 6a and the operations of forming heretofore described are again carl ried out.

In lconnection with the foregoing operation it should be noted that the cores are preferably slightly tapered to facilitate the operation described, and also to permit atmosphere to enter the articles when the cores are moved slightly in the manner described.

' From the foregoing description it will be seen that the isolated andY disassociated lower power unit or ram carries the core. Its sole function is to raise or lift the core into the suspended mold and hold the molded article underv pressure during the forming. When the fluid pressure is eased or released from the lower cylinder, thereby vfreeing the ram from its pressure, the ram ,with the mold ,core-is free to retire under the l weight of the ram so that the latter may idle back to its lowered position.

From the foregoing it is thought that the construction, operation and advantages of the here-l in described cold molding press will be fully u nderstood without further description and it is also to be understood that changes in the form, proportion and minor details of construction may be resorted to without departing from the spirit or sacricing any of the advantages of the invention.

' Having thus described my invention, what I 65 claim as new and desire to secure by Letters 75 2. In a press for molding battery cases, a taremoval of the molded article. Since the moldedv pered mold cavity with a mold consisting of a top plate .and `articulated floating side plates correspondingly tapered and designed to be seated entirely Within said cavity with a closing plate having cores, means for forcing said cores into engagement with said mold, and means for raising and lowering said mold.

3. In a mold for battery containers, an end plate, side plates hingedly suspended to the perimeter of said end plate, means to retain said side plates and end plate in engagement with each other, said means having internally heated walls, and a core mold adapted to force a mass of plastic material against the interior surface of said mold plates.

4. In' a press for forming plastic articles, a tapered mold cavity, and a mold consisting of a top plate and floating side plates correspondingly tapered and designed to be seated entirely within said cavity with a closing plate having core means, and means for forcing said core means into engagement with -said mold.

5. In a mold. for battery containers, an end plate,l side plates hingedly suspended to the perimeter of the end plate, means to retain said side plates and end plate in engagement comprising a member surrounding the mold throughout a substantial portion of its extent including the zone of hinged suspension of the said plates, said side plates being tapered, and said member correspondingly tapered, and a mold core adapted to force a mass of plastic material against the intrior surface of said mold plates.

6. In a press for molding plastic articles, a mold casing having a mold receiving cavity, an articulated mold suspended 'below said cavity, a closing plate having a core mounted below the mold, means for seating the mold into the cavity and ejecting it therefrom, and means for forcing the closing plate against the mold and for removing it therefrom and pulling the cores from the ar-` ticle.

7. In a press for molding plastic articles, a mold casing laving a mold cavity, a mold having a top plate and side plates suspended therefrom, means for seating "the mold in the cavity and ejecting it therefrom, a bottom plate provided with a core, and means for forcing said bottom plate against the mold and subsequently removing it therefrom.

8. In a press for molding plastic articles, a mold having a top plate provided with a concave rebate around its edges, side plates each provided with a convex bead for engagement with said rebate, and having their outer sides tapered, a mold on said movable platen, a mold case mounted on said stationary platen, an articulated mold supported in said mold case, said mold having a top plate and a plurality of side plates supported thereby, means on said mold plates for dowelling a molded article to the mol i, and means for ejecting the mold from the mold case after the core has been removed fromthe mold by downward movement of the platen, and thereby releasing the article from the dowelling means. 1

10. In a machine of the class described, a press ram, a press platen on the upper end of said ram, a container mold core on said platen, anupper stationary press plate above said platen, a llask having a mold receiving recess therein suspended from the under side of said upper press plate, a mold box adapted to t into said recess, a thrust rod secured to said mold box and extending upwardly through said upper press plate, and cylinder and piston mechanism adapted to operate said thrust rod to draw said mold box into said mold'receiving recess and force the same out of said recess.

11. In a mold for battery containers,- an end plate for forming the bottom of a battery container, side plates for forming the wallsof a battery container, said sideplates hingedly suspended to thevend plate, a retaining member for retaining the side plates in an erect position, andY engaging a substantial portion of the side plates when same are held erect and in molding position, and a core element for said mold, the said core element being tapered with relation to the side plates.v

l2. In a mold for battery containers, an end plate for forming the bottom of a battery container, side plates for forming the walls of a battery container, said side plates hingedly suspended tothe end plate, a retaining member for retaining the side plates in an erect position, and

engaging a. substantial portion of the side plates i when same are held erect and inmolding position, and a core element for said mold,` the said core element being tapered, and the said retaining member and the, side plates tapered correspondngly.

13. In a mold for battery containers, an end plate, side plates hingedly suspended to the perimeter .of the end plate, means to retain said side plates and end plate in engagement comprising a member surrounding the mold throughout a' substantial-portion of its extent including the zone of articulation of the said plates, said side plates being' tapered, and said member correspondingly tapered, and a mold core adapted to force a mass of plastic material against the interior surface of said mold plates, pressure means for enforcing relative movement of the core and mold plates whilethe latter are embraced in the surrounding member-to accomplish the molding, and means-for enforcing a preliminary separation between two of said three members, to wit, the surrounding member, the mold plates, and the mold core acting through a limited distance, and means whereby the force of gravity operating through an additional distance eiects separation of the third member, whereby all three members are separated from each other, permitting a withdrawal of the pressedA article from the plates released from the surrounding member.

LOUIS W. Ho'r'rEL.

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