US1534134A - Apparatus for molding hollow articles - Google Patents

Description

April 21, 1925.

T. E. MURRAY APPARATUS FOR MOLDING HOLLOW ARTICLES Filed Sept. 13 1924 anoenboz 777OI77Q6 5 War/a5 Patented Apr. .21, 1925.

' UNITED STATES PATENT OFFICE.

THOMAS MURRAY, '0' BROOKLYN, NEW'YORK.

AZPIFE'ARAYTUS r03. MOLDING HOLLOW ARTICLES.

Application filed September 13, 1924.. Serial No. rear/2.

application I have described an apparatus which can be used for producing short transportable sections of such conduits. The present application is in part a division. of the aforesaid application and is directed to the making of comparativelyshort sections of conduit and to the making of a variety of other articles of concrete and similar plastic materials; such, for example,

block to be molded.

as poles, planks, railroad ties, hollow bricks or blocks for the-building of floors, walls andpartitions and for the building of conduits for the distribution of fluids and similar uses. v

The -accompanying drawings illustrate embodiments of the invention.

Fig. 1 is a-perspective view of a block molded inaccordance with this invention.

Fig. 2 is aperspective view illustrating the method of molding such blocks.

Fig. an alternative arrangement, shown in perspective, ,ior molding such.

blocks.

of ducts greater than two,jan'd is particularly useful in making articles having a multiplicity of ducts rather than a single one.

The blocks are molded in a trough or box 3 open at the top, the depth of which corresponds substantially to the thickness of the The cores 4c are carried in the box in position to form the ducts 9. These coresare preferably of thecharacter described in my application No. 670,423, highly resilient rubber tubes with walls of sufiicient thickness and strengthto support the external pressures, and adapted when pulled endwise to contract transversely and break the adhesion of the rubber to the surrounding concrete so as to permit their withdrawal by continued longitudinal pulling. Cores ofth-is sort are provided of a length corresponding to that of a considerable number of the sectional blocks 1, and are used for molding a number of such blocks at once, so as to secure uniformity in the several blocks and to lessen the work involved in setting up and withdrawing the cores of a number of blocks by doing these things for .all the blocks at a single operation. The cores pass through properly spaced holes in. bulkheads or partitions 7, extending across the box at intervals and held by grooves (S in the side walls of the box engaging tongues on the side edges of the partitions. The cores 4i makea snug lit in the holes in the partitions through which they pass; and the ends of the cores (not shown) may betastened in any way to an end wall oi the box. The parts being set up. as illustrated in Fig. 1, concrete 7 is poured from a chute or nozzleS into the successive compartments in the, box, filling them to the top. The excess may be scraped off with a straight edge (andtamped if a dense product is desired) or the exposed side may be finished in any desired way.

\Vhen the concrete is sufiiciently hard the cores 4: are withdrawn by pulling the-m longitudina-lly. The molded. blocks can then.

be pushed up from below, either with the partitions or without these partitions. Or

.therpartitions may first be pushed out from below and the concrete blocks afterwards. A "false bottom or any one or various other known expedients may be used for lifting the molded blocks out of the box.

Fig. 3 illustrates the use of the invention in connection with a movable shield similar to thatdescribed in my previous application No. 722,913. Here the forward portions of the cores & are carried in tubes 9 in a sort of shield with a front wall 10 and a rear wall 11. The tubes 9 project through the rear wall 11 of the shield, as indicated, and are passed through openings in a series of bulkheads or partitions 12. The side walls of the box 1 are formed with openings 13 in their upper edges at certain intervals. T-shaped'brackets 14 are arranged to slide on the side walls of the box and length.

carry pins 15 which may be dropped into vanced and the partitions are caught in succession by brackets 14 placed at intervals along the sides; While the concrete is being poured into the mold thus formed be tween the partitions 12 and 12 theshield can be moved forward until the next partition 12 arrives at the desired point, where it will be clamped by means of brackets 14, sothat the filling of concrete may proceed in the space imn'iediately behind it while the shield and the other partitions are tak ing a further step forward. 13 are set so close together that the partitions may be fastened at intervals of varying length, depending on the length of the core which. will hold itself substantially straight when supported at the ends. of course, the partitions can be set closer if it be desired to make the blocks of less This arrangement has some advantages over the simpler arrangement of Fig. 2. It is easier to locate the partitions 12 on the extendedends of the metal tubes 9 than it is to locate them 011 a rubber tube. lVhen a partition, as 12, is fastened in place and the shield moved on to pull the rear ends of the tubes 9 out of the partition, the cores 4 will fit the holes in the partition with suliicient closeness to prevent the passage of the plastic material.

The shape ofthe box, which forms the outside of the molded article, can be straight or curved or of various irregular shapes. The flexibility oi": the cores. makes it possible also to bendthem around to form curved ducts. And where a plurality of cores are used they may be parallel or may converge according to the particular design otthe block and the duct required. In that case all the cores may be pulled out at one operation as by clamping them to the shield in Fig. 3, or they may be pulled out separately if that be more convenient; thus in building sections of a multiple-duct conduit all the cores may be pulled out of all the molded sections at one operation, with a great saving of time. And,though the invention may be applied to different styles of core, yet there are special advantages in simplicity and economy of production in the use of such resilient tubular The openings The ,cores described may also be .used with variousother styles of mold and with partitions between the successive molds whichare fixed instead of being movable like those illustrated.

Fig. 4 illustrates the making of hollow blanks or railroad ties or the like and hollow circular poles. The mold box 15 has a rectangular opening or trough 16 extending lengthwise of it, and a semi-circular trough 17. In theformer is a core 18 of highly resilient rubber, solid in the case illustrated, but it may be hollow if of sufficiently large size. In the semi-circular trough is a semicircular core 19, with the central portion removed. The cores are held at intervals in their length by partitions or bulkheads similar to those in Figs. 1 and 2. A cover 20,

preferablymade in sections, is removed during the pouring operation. The troughs are filled and levelled off and thecover laid on to secure an even finish on the upper surface. It will be understood, of course, that the trough 17 forms only a semi-circular segment of the post, two such segments being afterwards cemented together to make the finished product. Ordinarily, where two or moreniolds or troughs are arranged along side of each other in a single structure they will be of the same shape. I have illustrated diii'erent shapes in order to show the variety. of products to which the invention is ap plicable. o v I Although I have described with greatparticularity of detail. certainembodiments of my invention, yetit is not to be understood therefrom that the invention is restricted to the particular embodiments disclosed. Va-

rious modifications may be made by those skilled in the art without departure from the invention as defined in the following claims.

What I claim is 1. An apparatus for molding a plurality of hollow articles comprising a moldbox, partitions therein, and a core passing through the several partitions so that the same core serves in the several compartments sition during the casting of plastic material around it comprising means for supporting the core and a plurality of separate bulkheads at the rear of said supporting means adapted to be used in succession.

3. An apparatus for holding a plurality of cores properly spaced during the casting of plastic material around them, comprising means for supporting said cores in proper relative positions and a plurality of separate bulkheads at the rear adapted to be used in succession. I

4. An apparatus'for molding hollow arti lit) cles comprising a plurality of molds and a common core passing through said molds, said, core being tubular, of sufiicient strength to support the external pressures and of such a composition that when pulled it Will con tract transversely and separate from the surrounding material so as to permit its Withdrawal and of such resiliency that when released it will resume its original shape.

5. An apparatus for holding a core properly spaced during the casting of plastic material around it, comprising means for supporting said core in proper positions and a plurality of separate bulkheads at the rear adapted to be used in succession.

6. An apparatus for holding a plurality of cores properly spaced during the casting of plastic material around them, comprising means for supporting said cores in proper relative positions and a plurality of separate bulkheads at the rear adapted to be used in succession.

In Witness whereof I have hereunto signed my name.

THOMAS E. MURRAY.

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