USRE14603E - roberts - Google Patents

Description

F. T. ROBERTS.

PROCESS OF AND APPARATUS FOR MAKING HOLLOW RUBBER ARTICLES.

APPLICATION FILED JUNE 3. i918.

Reissued Mar. 4, 1919.

4 SHEE' [SSHEET 1.

F. T. ROBERTS.

PROCESS OF AND APPARATUS FOR MAKING HOLLOW RUBBER ARTICLES. APPLICATION. FILED JU.NE3. 191s.

Reissued Mar. 4, 1919. 14,603.

4 SHEETS-SHEET 2.

JWV'ENTOR Jayme W F. T. ROBERTS US FOR MAKKNG ATlON FILED JUNE HOLLOW RUBBER ARTICLES.

3 HHS,

PROCESS OF AND APPARAT APPLIC Reissued Man. 4, 1919.

'JM ENToR: 6 /Z W PM,"

. ATTKS.

F. I. ROBERTS. PROCESS OF AND APPARATUS FOR MAKING HOLLOW RUBBER ARTICLES.

APPLICATION HLED JUNE 3, IBIS.

Reissued Mar. 4, 1919.

JNVENT'ORI FRED monies aonnnrs,

OF CLEVELAND HEIGHTS, OHIO, ASSIGNOR TO THE ARANAR COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

YBOCESS OF AND APPARATUS FOR MAKING- HOLLOW RUBBER ARTICLES.

Specification of Beissued Letters Patent. Reissuedluar. 4 1919.

Original No. 1,219,851, dated March 13, 1917, Serial No. 125,598, filed October 14, 1916. Application for reissue filed June 3, 1918. Serial No. 238,013.

DIvIsIoN A.-

To all whom it may concern: 1

Be it known that I, FRED THOMAS ROBERTS, a citizen of the United States, residing at Cleveland Heights, in the county of Guyahoga and State of Ohio, have invented a certain new and useful Improvement in Processes of and Apparatus for Making Hollow Rubber Articles, of which the following is a full, clear, and exact description, referonce being-had to the accompanying draw ings.

- This invention relates to the productionof hollow rubber articles which may contain, either permanently or temporarily, an 1 internal air pressure. A convenient illustration of such an article is a playing ball, though many sorts of articles may be constructed by the same process, for example, bulbs of various sorts, rubber toys, hot water bottles, tubes for pneumatic tires, etc., in all of which cases an internal fluid pressure is desirable, at least until after the article has been vulcanized. My invention provides an air-tight room of sufficient size to accommodate one or moreworkmen, and means for maintaining compressed air having the desired pressure, within the room. Access to the room or exit therefrom, for the operators, the molds and the materials, is efiected by means of an air lock associated with the room. In this room the operator brings together, mechanically or by hand, the parts of the article, soas to entrap air within it. Thereafter, the article with such entrapped air, is held between mold members which are removed from the room and placed in a suitable vulcanizer, where the curing is completed.

In addition to the steps above broadly out-- lined, my process includes various other features, any or all of which may be employed, as desired. The first additional feature to which I call attention is the pneumatic forcing of rubber stock to its seat in forming molds by simply venting the mold cavities to the outside atmosphere, enabling theair pressure within the room to form the parts of the article before they are brought together to entrap air. Another additional feature which may be employed in my process accomplishes the entrapping within the article of air of a higher pressure than suitable for the operator to continuously breathe, and of a higher pressure than the mere adherence of raw 5 rubber parts would retain. This is efi'ecteclby surrounding the separated mold members in the room by a easing into which compressed air of a higher pressure than that in the room may be forced.

Other specific features of operation which may be employed in my process will be hereinafter more fully explained. My inventlon includes also certain apparatus for effectively carrying out parts of-the process, as hereinafter described. 7

The drawings illustrate the air-tight room and diflerent forms of mechanism which may be used therein for carrying out my process. Figure 1 is a side elevation o the air room with its air look, a suitable mo ding press within the room being shown in dotted llnes; Fig. 2 is a sectional plan of such apparatus; Fig. 3 is a vertical section, on a larger scale, of the molding press shown in Fig. 1, this view beingat right angles to the plane of Fig. 1; Fig. 4 is a plan of a mold plate which may be employed; Fig. 5 is a cross section of two of such plates, showing their relative position before they" are brought together; Fig. 6 is a plan of a clamp whlch may be used to. hold a rubber sheet to one of the mold plates, as illustrated in Fig. 5; .Fig. 7 is an enlarged view in vertical section illustrating one of the mold cavities and showing rubber stock in place therein; Fig. 8 is a view on the same scale as Fig. 7 showing a vulcanizing mold which may be employed with the article illustrated in Fig. 7 Fig. 9 is an outside view of a ball produced. by the molds shown in Figs. 7 and 8; Fig. 10 is a side elevation of a simpler formof'mold press, which may be employed for some purposes; Fig. 11 is a plan of such mold press; Fig. 12 isa vertical cross section, on an enlargedscale, through one of the mold cavities of the mold plates shown in Figs.10 and 11; Fig. 13 is a perspective view illustrating a hand operation of bringing two article-parts together; Fig.

j 14 isa vertical section through a vulcanizing' mold for use when the hand operation illustrated by Fig. 13 is emplloyed Fig. 15 is an outside view of the artic e produced by either the mold shown in Fig. 12, or that in Fig. 14. In Figs. 1, 2 and 3, an air-tight room is shown comprising a partially cylindrical wall 1, a. base 2 a cover 3, and a door 4. This door also forms the inner door of the air lock, which. comprises a rectangular chamber bounded by an extension 5 of the base, vertical walls 6 and 7 and An outer door 9 completes the air lock. The vertical walls, tops and base shown are secured together in an air-tight manner. It is convenient torivet the tops to the vertical walls and rivet the walls (Sand 7 tothe cylindrical wall 1 and provide these walls with base flanges-10 and 11, by whichthey may be secured to the base 2 by bolts 12, a suitable gasket 13 being emplo ed between the flange and base. This'ena les the body of the casing and lock to be separated from the base and elevated to allowthe mold press to-be conveniently installed on p the base.

Suitable gas'ketsare provided around the doors 4 and .9,- to enable these doors to make an air-tight connection, and the doors are p'rovidedwith locking levers 14 and 15, enabling either door to'be locked unlocked from within the airlock or on V the other side thereo i 16 indicates a pipe adap compressed air from a suitable pump or other soilrce. One branch 17 of this pilp'e leads into the an room and is controlled y 'a valve 18 therein, and other branches 19 the air lock, being conand 20 lead into trolled by valves '21 and22, res ectively inside of thelock and outside. 0? dicates a vent pipe from the air room to theouter air, being controlled by a valve 24 within the room. 25 and 26 indicate vent pipesfrom the air lock, controlled by suits able valvesinside and outside of the ,lock respectively. 27 and 28 indicate valved passageways whichma be provided, between theroomand air loc to insure equalization of pressure.- Suitable pre'mure gages, will be provided forthe room and air lock, as

" well as suitable means for illuminating the interiors. These, and other accompaniments adding to the conveniences of opera tion, are not shown. 3 v

From the above description it will be seen that the air under a pressure in which a workman may conveniently operate may readily be maintained within the room, while access to or from the room may be 7 efl'ected through the air look, without disturbing the internal pressure. This air lock 2 also enables the passage of molds and material to and from the room.

ted .to donve'y 3 it- 23 inthe ventin pipes 50 and 53 the upper mold, and a similar sheetmay be in the article a sti 1 higher pressure, If desired, as heretofore referred to. This may be -more apparent as the following description proceeds. 30 in Figs. 1 and 3 indicates the base of the mold press from which rise standards- 31 carrying a head 32. On the base is shown a frame 33 carryin ders 34,, from which rise p ungers 35, which carry at their tops a hollow platen 36. A hollow platen 38 is also shown as secured to the underside of the head 32. Each of these platens has passageways which com- ,municate with cavities in mold members 40 and 41 secured to the respective platens. Figs. 4 and 5 illustrate one form of mold plates, which may be securedtothe plata pair' of cy1in-- ens by suitable fasteners. The cavities 43,

as they appear in Fig. 5, have a peculiar shape which, will be hereinafter referred to. These cavities -have:vents 44 which are adapted to register with openings in the hollow platens. 50 (Fig. 3) indicates a vent pipeleading from the platen 38.- 51 is a vent passageway'within-one'of the plungers 35 leading from'the platen 36. This passageway communicates with a flexible pipe 53. The pipes50 and 53' are shown'as join ing and leading outwardly bya T-connection through the pipe 55, which is provided with a valve 56.

By means of the piping-described and the valve 56, the operator-may place the mold cavlties in communication with thevouter' air. Accordingly, if an air. pressure be maintained within the room and rubber stock be placed across the mouths of the cavities of on of the molds, and that mold caused to communicate withthe outer air, the pressurewithin the room will force the stock into the cavity. It is convenient to 'vent both molds at the'sametime, and accordingly are brought together an having separate valves, as might be done if desired. 3 I H r Fig. 5'shows a sheet of stock A held across held across the lower mold. It maybe deone valve provided, instead of. 11b

sirable to clamp this sheet at the edges of the mold. For that purpose, I may provide a rectangular frame, shown in Fig. ,6. This frame, as shown, consists of two members 60 and 61, each extendin around two sides of the mold and provided at their ends 'with means for drawing the members together, as for example, the thumb nuts 63 on ping within each article air bolts 64. For some purposes it may be sufiicient, to simply lay the stock across the mouths of the molds and then vent them. Or the vents may be slightly opened and then the rubber stock placed against the mold face, when it will immediately sink into the cavities.

After the molds have been vented, so that the pressur within the room has seated the stock in the mold cavities, the molds are brought together to bring the two parts of the article into conjunction thus entraphaving a pressure equal to that surrounding the mold. It is convenient to bring the mold members together by hydraulic pressure. For this purpose cylinders M and plungers 35 are provided. indicates a pipe adapted to convey liquid under pressure to the cylinders 34. 71 is a valve controlling this pipe adapted to place it in communlcation with the supply, or close it entirely, or drain i through the pipes 72*? 3.

It should be noted that when these two mold parts are brought together with rubber stock seated, inthem respectively, they produce a series of hollow articles, as shown at A inFig. 7, with air entrapped within them. I prefer to provide a depressed portion 46 of the plate about each mold cavity, and bring the walls about the cavities to substantially an edge, as shown at 47. By this construction the sheets of rubber are cut in two around the article as the mold members come together, the excess of rubber pass ing into the space L6 surrounding the cavities. It will be noted that the annular wall between the mold cavity and the surrounding s ace is tapered both inwardly and outward y, in coming to the cutting edge. This enables the rubber of the two sections to be squeezed together between mold surfaces, as the molds come together, thus making an effective seam. The outward rib thus produced is absorbed in the vulcanization.

As heretofore mentioned, for many purposes pressure of air in which the operator may conveniently work may be as high as desired within the article, and in such case it is only necessary to provide so much of the apparatus as has been described, or a substitute for those parts, as hereinafter referred to. For some purposes, however, it is desirable to obtain within the article a higher pressure than it is healthful for the operator to continuously breathe. For this purposeI provide the additional portion of the mechanism which will now be described.

Within the frame'member 33 is a central hydraulic cylinder 80, adapted to be fed bya pipe 81, controlled by a valve 82, which may drain through the passageway 83 to the pipe 73. Rising from this cylinder 1s a plunger 85 carrying a-box 86, which has ears 87 slidably embracing the standards 31. The plungers 35 extend through the base of this box 86 in a slidable but air-tight manner, stufiing boxes being omitted for simplicity of illustration. Directly above the wall of the box 86 is a rectangular gasket 88, carried on the under side of the platen 38. 90 indicates a pipe for compressed air passing from outside of the room to the interior of the box 86, this pipe being connected with the box by a flexible connection and being controlled by a valve 91. v

Now if it be desired to entrap within the article air of a higher pressure than that within the room, the parts of the rubber stock are caused to seat in their cavities by opening the vent valve 56, as already described; then, before the mold parts are brought together, the valve 82 is opened and hydraulic pressure admitted to the cylinder 80, which raises the box 86 and forms a closed chamber about the mold members.

' Then the valve 91 is opened and compressed air of any pressure desired is admitted to the interior of the box 86, the pressure being indicated by the gage 93. When the desired pressure is obtained within the box the valve 71 is opened and the plungers 35 I raised, thus closing the mold within this surrounding air of higher pressure.

After the parts of the article have been brought together within a surrounding atmosphere of compressed air (either the "air which fills the entire room or the comparatively'high pressure air within the box), it is desirable. to remove the articles from the molds LO and 41 for vulcanizing. By removing them and vulcanizing them in a separate mold, and outside of the press'shown, one press may be operated continuously in the formation of the article, and vulcanization of'a number of molds may be performed at one time in a vulcanizer. This has advantages of economy of equipment over vulcanizing in the press where the article is formed.

In the operation of the apparatus without employing the higher air pressure and without using the box 86,- air of a pressure equal to that which is within the room generally is entrapped within the article. Then, after the molds are separated, the articles are taken out of the molds and placed in another mold within the same room, which mold is clamped together to hold the articles with the entrapped air. This mold is then removed for vulcanization. Such a mold 1s illustrated in Fig. 8, and is shown as having two mold plates 100 and 101, clamped together by a beveled Wedge-shaped stirrup 102, which overhangs wedge ribs 103- and 104 on the mold members.

It is convenient, of course, to have 'a cornparatively large number of these vulcanizing molds within the room, which are :filled one after the other, clamped, and removed together, to avoid air-losses in the lock. 110-- and 111 in Fi' 2, illustrate two su ports or" tables adapte to carry respective y emtpty molds and filled molds, and ii: is to be un erstood that after theoperator has filled a sufficient number .of molds for vulcanizing, he places them in the air lock 5, and closes the door 4. The air ressure is then reduced within the air 1 from the outside (by means of the external valve on the vent 26) and then the supply of molds is removed and a supply of empty molds placed in the air lock, the door closed and the-pressure built up, through the passageway controlling the external valve 22.

During the operation of transferring the closed articles which contain simply the room-pressure of air, from the mold press to the vulcanizing mold, there is no tendency of the articles to separate, because the pres sure outside of the article is the same as that within it. I find, "however, that the adhesionof the raw rubber will hold aconsiderable air pressure within the articles, and the pressure supplied to the box 86 exceeds the air pressure within the room by an amount which should be less than that which the adhesionxoff the raw rubber will hold.

Accordingly, by using the pressure in the room and also the pressure within the box, I can have the advantage of obtaining a higher pressure within the article thanthe adhesion of the raw rubber itself will hold,

and a higher pressure than it is healthful for an operator to work in. lean, accordingly, obtain this high pressure and still have the 'cheapnws of operation resulting from transferring the molded articles from their forming molds to vulcanizing molds.

To make a concrete illustration of this built-up air pressure within the article, sup-1 pose the adhesion of raw rubber stock will hold a pressure of fifteen pounds per square inch above the atmosphere,andsuppose that an operator may conveniently work in an air pressure of twenty-five pounds. Then if the article were closed within a chamber containing an atmosphere of compressed air of over fifteen pounds pressure, as described in' my prior Patent'No, 1,146,523, issued July" D 13, 1915, it would not be feasible to. transfer the article in the open. air to another mold sure would cause it to separate. Hence, in carrying out the process of that patent the article has been vulcanized in the same mold in which it was placed to entrap air. If, however, the article be closed by the present Jprocess, in aroom containing an air pressure of twenty-five pounds, it may readily I be transferredto a vulcanizing mold while the latter is in that room, and thus a pressure for vnlcaniz ing, because the internal. pres.-.

of twenty-five pounds obtained within the and forty pounds in the box 86. Accord ingly, I Wlll entrap air'of forty pounds pressurewithin the article (which pressure, it is assumed, would be inconvenient for the operator toqw'ork in), and still may avail myself of the economy of transferring the article to another vulcanizing mold in the room, because the difference between the internal-land external pressure in the article is only fifteen pounds. It is to be understood that the actual pressures of" fifteen, twenty-five and forty pounds above referred.

to, are selected simply as illustrative, and

will vary with circumstances.

It should be noted that the opening of the box 86 discharges thehigher 'pressure airinto'the'room and thus to a greater or less extent may compensate for lea age from theroom. In any event, the pressure in the room is maintained at the desired amount (indicated by some suitable gage, not shown) by occasional operation of the admission and venting valves 18 and 24. The

vent pipe 23 may conveniently lead from the bottom of the room and the admission pipe 17 enter at the top, so that the operator may use these pipes for supplying fresh air as needed for respiration, the vent valve 24 bein occasionallyo ened to allow the exit of t e carbonic aci which would accumulate near the floor. p

While the above described press is very satisfactory for accomplishing the entrapping of air, whether it be of higher pressure than that in the room or of the same pressure, a much simpler form of press may be used in the; latter case. Such simpler form is illustrated in Figs..10, 11 and 12, where 120 and 121 are two cavity mold plates adapted to be held separated or snugly brought together by a screw 123.

TlllS screw is shown as having a head 124 rotatably held the mold plate 120, having threads engagmg internal threads in the mold plate 121. A removable socket wrench 125- provides means for rotating the screw. owelwpins'126 properly position one mold plate over the other. This mold press may conveniently be carried on the portable support indicated at 128. 1

In operating the mold press just de-' scribed, hollow shown at B, B may vbe supplied to the operators within the room. Such. operators separate the mold plates sufliciently'to insert these hemispheres and then turn down the screw, bringing the parts together'to entrap the air of the semi-cured hemispheres, 1

ressure within the. room. If the article to made in this form fore being placed in the vulcanizing mold, described and claimed herein,

In operating with semi-cured stock the ad- .have found that in pneumatically forcing 14,eos C i a is a ball it may conveniently have overjust described,-and the process including as lapping beveled diametric edges, as india step the use of such mold are claimed in cated at 'b in Fig. 12. After the parts of a division of the present application filed the article are brought together, thus en-v concurrently herewith and numbered Serial trapping air of the pressure within the No. 238,014 and intended to issue concurroom, the mold with its closed articles is rently herewith. fThat application explains removed and placed in the vulcanizer. It further characteristics and advant es of is convenient to allow a number of these the mold illustrated inFig. 7. The lnvenmolds to accumulate in the room, to prevent tion covered in the present application is inloss of air in the air lock. dependent of the form of the mold.

Figs. 13 and 14 illustrate a still simpler When the distorted ball is removed from way of making an inflated hollow rubber the mold of Figs. 5 ad 7, it is put into a article. In this case the two article-sections spherical vulcanizing "cavity, as shown in (shown as hollow hemispheres B, B, with Fig. 8. It is convenient to make the article beveled edges b), have cement placed on slightly smaller in diameter than that of the their meeting edges and are simply brought vulcanizing cavity, as illustrated in Fig. 8, together by hand in the room, as illustrated as this provides for the expansion of the b the operators hands C in Fig. 13. When article during vulcanization and also ent e parts of the article are thus brought toables the article to be very readily placed gether, inclosing air of a pressure equal to in the vulcanizing mold. that in the room, the closed article is placed If the internal pressure in the article is in a vulcanizing mold within the room. greater thanthe atmosphere in the room, the Such mold is illustrated in Fig. 14, comarticle will assume a spherical shape as soon prising the plates 130 and 131, and a suitas removed from 'themold of Figs. 5 and 7. able clamp for holding them together. This N If the higher internal-pressure, obtained by clamp may consist of a wedge-shaped stirusing the box 86, .is not employed, the arrup 132 overhanging wedge-shaped ribs 133 ticle may be of a dented. shape when it is and 134, as heretofore explained in connecplaced in the vulcanizing mold, but it will tion with Fig. 8. The article is placed in assume true spherical shape when the vulthis mold with the diametric seam out of canizing mold is removed from the room, as registration with the faces of the molds, the air in the mold cavity outside of the ar-- as illustrated in Fig. 14, the result being ticle'will leak out between the mold plates. that the seam has a very firm surface to My prior patent No. 1,201,627 issued rest against during vulcanization, and ef- October. 17, 1916, shows and claims a system fective joining is accomplished. of removing hollow inflated articles from Fig. 15 illustrates a ball B made in either molds, consisting of opening the mold, as it the molds of Fig. 10 or those of Fig. 14. comes from the vulcanizer, within an air chamber containing air under pressure, this hesion is not as great as with raw rubber air being reduced in pressure after the mold stock, but where the internal air is at the is p n d s oper tion prevents concensame pressure as that within the room there trated bulging of the article at th line of is no tendency of the parts to separate beeparation. Now my air room operation,

may accomand that mold holds them in shape until pllsh an analogous result. The molds, the are vulcanized and the seam thus cured.

B igs. 5 and 7 show a peculiar form of may be taken from the vulcanizer, and, after mold adapted for use in making a ball. I cooling, passed into the air room, and there I opened. The pressure within the article is rubber stock into cavities the effect is to thus entirely or partly counterbalanced, by stretch the stock most at the central porthe external pressure in the room, and the tion, leaving it thicker adjacent to the edges troublesome concentrated bulging does not of the mold, and, accordingly, it is difficult result. At some convenient time the finished to make, by such process, a wall of uniform articles are removed from the room through thickness from initial stock which has a unithe air lock, where the pressure is gradually f hi k T save th expense d reduced. There is, accordingly, no strain difliculties of forming the stock of irregular 0n the-articlethickness, to compensate for the difierentgsg It will be seen from h b VB description stretching, I have devised the mold shown in that the apparatus shown is adapted for a Figs.'5 and 7, wherein there. is an inward protuberance 48, which supports the central portion of the stock and causes the'stretching action to take place where needed, in-

stead of at the center.

The characteristics of the distorted mold number of different specific operations in performing my process. The apparatus is ofipmy invention, and important and novel parts thereof are claimed herein, but I do not wish to be limited to the apparatus shown, as the process may be performed clamped shut with their inclosed articles,

Ill

what I claim is:

with various forms of apparatus, as already explained. It is operated somewhat dlfierently when using semi-cured molded rub- .ber sections than when making the articles from raw rubber, pneumatically. seated. The additional step of giving the superpressure within the article is also of Value, but need not be em loyed unless desired.

Reference shoul be made to my Patents Nos. 1,201,502 and 1,201,503, issued October 17,1916 for claims covering the process of pneumatically seating the stock in. vented mold cavities by a superior pressure within the article, and covering also.

the moldpress having mold plates and hel low platens, as shown in Fig. 3. v v

Having thus described my nvention,

1. The process of making hollow articles of plastic material consisting of bringlng the parts together within a room occupied by the operator and containing air underpressure. V

.2. The process of making hollow artlcles of plastic material consisting of bringing, the parts together within a room occupled by the operator and containing air under pressure, holding the closed article in" a vulcanizing mold and vulcanizing the article while so held.

.3. The process of making hollow rubber articles consisting of bringing the parts of the article together in a room occupied by the operator and'filled with compressed air, holding the parts together by mechanical means while they are removed from the air room, and vulcanizing the article outside of the air room.

4. The process of making hollow rubber articles consisting of bringing the parts of the article together in a room occupied by the operator and filled with compressed air, holding the parts together by a vulcanizing .mold closed within the air room, removing such mold with its inclosed article from the air room, and vulcanizing the article while in said mold.

5. The process of making hollow rubber articles consisting of bringing the parts of the articles together in a surrounding atmosphere ofcompressed air, then transferring the article to a vulcanizing mold located in such compressed air atmosphere, closingthe mold in such atmosphere, and vulcanizing the article.

6. The process of making hollow articles consisting of bringing the parts of the article together in a surrounding atmosphere of compressed air,- transferring the article to a vulcanizing mold while .in the same surrounding. atmosphere, locking said mold shut, removing it from the atmosphere, and

vulcanizing the article while in said mold.*

7. The process of hollow rubber prior compressed air,

does not exist, whereby articles consisting of brin the cupshaped parts of the article while retained in mold members into edge engagement in a room occupied by the operator and containing air under pressure, then transferring such article to a separate vulcanzing mold in said room and closing the mold, then removing such closed mold from such room, and vulcanizing the article while it remains in that mold.

8, The process of making hollow rubber articles consisting of closing the parts of the article within an atmosphere ofcompressed air in a room occupied by the operator' and to which access is had by means of an air lock, and thereafter vulcanizing the closed article.

9. The process of making hollow rubber articles consisting of closing the parts of the article Within an atmosphere. of compressed air in a room occupied by the operator and to which access is had by means of an air lock, placing such closed article.

said. room, and removing the closedmold from said room by means of an air lock, and vulcanizing the article while in said mold outside of said room.

10. The process of making hollow rubber articles consisting of bringing the parts of the article together in an atmosphere of then placing such closed article while in canizing mold with the seam of the article out ofregistration with the separation faces of the mold, and 'vulcanizing the article While held in such mold.

11. The ber ball consisting of bringing hemispherical sectionstogether-in a room occupied by the operator and filled with co procem of making a hollow rub pressed air,

such atmosphere in a vul-' then placing such closedball in a two-part sphericalmold with the seam out of registration with the separation faces of the mold, locking such 'mold,-removing it .from theair room, andheating the mold .to'vuh can ze the articles 12. The process of making hollow articles of plastic materials, consisting of placing rubber stock across the'mouth of a mold cavity, and, while the mold is located in an atmosphere of compremed fluid, venting the cavity to the outside to allow the compressed me the stock toseat in the.

fluid pressure to 0 mold cavity, brlngmg such formed part into conjunction with another part, andcuring the closed'article.

13. .The process of articles,

mold is located in an inclosu're containing an under pressure,

venting the mold cavity hollow rubber v consisting of placing raw rubber stock across the mouth of a mold while the p to'a point where as high an air pressure the rubber stock is seated in the cavity, then bringing such seated stock into conjunction with other stock to form a closed article with compressed air,-venting the cavity to the outside air to allow the compressed air pressure to force the stock to seat in the mold cavity, bringing such formed part into conjunction with another part to entrap compressed air, transferring the closed article to a vulcanizing mold and vulcanizing it therein.

15. The process of making hollow articles by the employment of an air-tight room in which the operator works and which contains air under pressure, consisting of placing plastic stock in such room across the mouth of mold cavities, venting such cavities tothe outside air whereby the pressure in the room seats the stock, and bringing two of such seated parts together in said room to entrap compressed air between them.

i 16. The process of making hollow rubber articles consisting of placing raw rubber stock across the mouths of mold cavities in a mold contained in a room in which the operator works and which is filled with compressed air, venting such cavities to the outside air, whereby said compressed air seats the rubber in the cavities, bringing two of such seated parts together in said room to entrap compressed air within the article, transferring the closed article while in the room to a vulcanizing mold and vulcanizing the article.

, 17. The process of making hollow rubber articles, consisting of placing rubber stock across the mouth of a mold cavity, while the mold is located in a' room in which the operator works and which ;is filled with compressed air, then venting the cavity to the. outside air to allow the compressed air pressure to force the stock to seat in the mold cavity, then bringing such formed part into conjunction with another part in the same room to entrap air under pressure within the article, then transferring such article while in the room to a vulcanizing mold which is then closed, removing the vulcanizing mold from the room and thereafter vulcanizing the article therein.

"18. The-process of making hollow articles of lastic material consisting of closing the art1cle within an atmosphere of compressed fluid, which atmosphere is contained in a separable casing located in a room containing compressed fluid of lower ressure, re-

moving the article from the high pressure chamber into the low pressure room and placing it in a mold in such room, and curing the article. A

19. The process of making hollow rubber articles consisting of closing the article within an atmosphere of compressed air, which atmosphere is contained in a separable casing located in a room containing compressed air of lower pressure, removing the article from theehigh pressure chamber into the low pressure room and placing it in a mold therein, removing such mold in a closed condition from such room and thereafter heating it to vulcanize the inclosed article.

20. The process of making articles containing fluid under pressure comprising the bringing of the parts of the article together in an atmosphere of fluid under pressure which is contained within a casing located within a room in which the operator works and which contains air under pressure but of a lower pressure than that within the casing, then opening the casing and removing the article into the room, and placing it in a moldjtherein.

21. i The process of making inflated rubber articles containing fluid under pressure comprising the bringing of the parts of the article together in an atmosphere of air under pressure which is contained within a casing located within a room in which the operator worksand which contains air under pressure but of a lower pressure than that within the casing, then opening the casing and-removing the article into the room and placing it in a vulcanizing mold located in the room, then closing the vulcanizing mold and removing it from the room and heating it to vulcanize the article. I

22. The process of making Hollow articles. having an internal air pressure, consisting of placing stock for the article across the mouth of a mold cavity which is located in an inclosure which contains compressed fluid, venting the cavity to a point outside the inclosure to enable the compressed fluid to seat the stock in the cavity, 'forming a smaller inclosure about the seated article and supplying fluid under still'higher pressure to said smaller inclosure, bringing the seated article while in said smaller inclosure' into conjunction with otherstock to entrap high pressure fluid within it, removing the article into the larger inclosure, and placing it in a mold therein, and curing tha article.

23. The process of making hollow rubber articles having an internal air pressure consisting of placing stock for the article across the mouth of a mold cavity which is located. in a room in which the operator works and which contains compressed air, venting the cavity to a point outside the room to enable the compressed air to seat the stock in the cavity, forming an inclosure about the seated 4 process descrl vided with an airlock,

,vulcanizing mold in said room,

plying. air (pressure to said inclosure,"

article while in said inarticle within the room and. sup under still higher bringing the seate closure into conjunction with other rubber stock to entrap high pressure air within it,

o eningthe'inclosure and removin the artice to a'place 1n the room 0111381 e of said.

inclosure, placing the removed article in a and heating said mold to'lvulcanize the article.

24. An ap aratus for carrying out the 'hed comprising a room adapted to house the operator, means for admitting com ressed air to the room, a cavitarymold. in t e room, and means for causing pneumatic communication between the mold cavity in the room and a point outside of the room.

25. An apparatus for carrying out the process described comprising a room promeans for admitting compressed air to the room, and means for venting .a mold cavity in the roomrto a point outside of the room.

26. In an apparatus of the character described, the combination with suitable walls providing a'closed air chamber, an air lock adapted to communicate with said chamber and having two doors leading to and from the lock, pipes for conveying compressed air from the interior of theroom, a cavitary mold in said room, and a pipe leading from the mold cavity to a point outside of the 27...In an apparatus of the character described, the combination' of an air-tight "room, anair lock adapted to enable communlcation wlth the room, compressed 311' plpes and vent pipes commumcatmg with the room and with the air look, amoldwith in the room having cavities, passageways from said cav1t1es room, and a valve for controlling such pasentra air from the room within sageways, whereby the cavities may be vent- .ed when desired. v 28. In an apparatus of the class described,

the combination of an air tight room in which an operator may work, means for maintaining an air pressure Within said room,-a pair of mold parts within the room, and means for bringing them together to an article seate in the mold members.

29-. The combination of a room in which an operator may work,,means formalntalning air under pressure therein, a mold press airto the room,

i about the to a point outside of the plying fluid unde'rlhigher pressure to the inclosure.

31. The combination of a room adapted to be occupiedby the. operator, molds therein aving cavi-tles, molds, means for supplying compressed air to the room, means for supplying compressed air of higher pressure to the inclosure, and means for venting the mold cavities to a point outside of the inclosure.

32. In an apparatus of the characterdescribed, the -combination of an air tight room, an air lock adapted to enable communication with the room, means for supplying compressed air to the room and air look, a mold within the room having cavities, passageways from said cavities to a point outside of the room, a valve for con- 33. The combination of a room adaptedto be occupied by the .operatona mold press n therein, means for supplying compressed means for venting the mold press to a point outside of a casing, means for placing it vented cavities, plyingcompressed fluid to the interior of the casing, and means for bringing such seated article part into conjunction with another part of the article while in said casing and while the pressure therein is maintained higher than that'in the room, means for then opening the casin .enabling the removal of the articles wit the entrapped air,-and' amold in theroom and outside of the casing in which such article may be placed and held.

In testimony whereof, I hereunto aflix my signature.

. FRED THOMAS ROBERTS.

cavities in the the room,

means for supan inclosure about the

Images