US2316352A

US2316352A - Vulcanizing press

Info

Publication number: US2316352A
Application number: US287294A
Authority: US
Inventors: Rupert G Minns; Henning T Tornberg
Original assignee: National Rubber Machinery Co
Current assignee: National Rubber Machinery Co
Priority date: 1939-07-29
Filing date: 1939-07-29
Publication date: 1943-04-13
Anticipated expiration: 1960-04-13

Description

April 13, 1943- R. G. MINNS ETAL 2,316,352

VULCANIZ ING PRES S Filed July 29, 1939 8 Sheets-Sheet l INVENTOR 2 RUPERT e. Mums & BY HENN\NC1 T TORN BERG ATTORNEY April 13, 1943;

R. .G. MINNS ETAL VULCANIZ INQ PRES S Filed July 29, 1939 8 Sheets-Sheet 2 IIII lNVENTOR cm 5 N W M. G T R E P U R HENMNG T. TORNBERG BY W ATTORNEY April 13, 1943.

FIG. 3

R. G. MINNS ETAL ,VULCANIZING PRESS Filed July 29, 1939 8 Sheets-Sheet 3 INVENTOR RUPERT G.M\NNS HENN\NG T. TORN BERG ATToRNm? R. G. MINNS ETAL VULCANIZING PRESS April 13, 1943.

Filed July 29, 1939 r N INVENTOR R UPERT c1. MmNs a HE N NING T. TORNBERG ATTORNEY MINNS ETAL VULCANIZING PRESS April 13, 1943.

Filed July 29, 1939 8 Sheets-Sheet 5 IIIIIIIIIJ INVENTOR RUPERT G. MlNNS 23 HENNMG T. TDRNBERQ ATTORN EY April 1943- R. G. MINNYS ETAL 2,316,352

VULCANI Z ING PRES 5 Filed July 29. 1939 s Sheets-Sheet 6 INVENTOR RUPERT (a. M\NNS ix 7 W HENMNG T. TORNBERG ATTORN EY April 13, 1943. GWNNS ET AL 2,316,352

VULCANI Z ING PRES S Filed July 29. 1939 8 Sheets-Sheet 7 INVENTOR RUPERT G. MlNNS HENN\NG T.'\'0RNBERG ATTORNEY April 13, 1943.

YULCANIZ ING PRES S G. MINNS EVTAL 2,316,352

led July 29, 1939 8 Sheets- Sheet s 2M0 FIG. 9

P PILOT CJRQUITH 1 l 5 Z CIRCUIT POWER PRESS PERAT LIMIT $WITCH PREss OPERATED LIMIT swn-cu 3 SNlTCH Pitessuae S OPERRTED $RFET v REvERsE COIL V ERLQAD RELFNS F RWARD Con.

b Fl 9. \2 2 START OF CYCLE STERN on VENT 0N Y 1mm \RQulT L MZ END OF CNCLE l3! I50 INVENTOR 150 I RUPERT G. M\NNS 8x HENN\NQ\ T- men BERG L3 T I M \TMER MOTOR ATTORNEY Patented Apr. 13, 1943 VULCANIZING PRESS Rupert G. Minns and Henning T. Tornberg,

Akron, Ohio, assignors to National Rubber Machinery Company, Akron, Ohio, a corporation of Ohio Applicatien July 29, 1939, Serial No. 287,294

11 Claims.

This invention relates to vulcanizing presses, and in particular relates to presses for vulcanizing sponge rubber articles, such as vehicle seat cushions, mattresses, or the like.

The general purpose of the invention is to provide an improved press unit of simple, compact and powerful construction, in which a plurality of superposed platens carrying mating mold sections are relatively movable to open positions which facilitate free access to the mold sections, as for example, for pouring liquid compounds, such as beaten latex or chemically treated rubber compounds used in manufacturing sponge rubber articles, into the lower mold cavities without interference from the adjacent platen.

Another object of the invention is to provide a press unit of the character described having means to prevent the press from opening if the steam in the curing chamber thereof is above a predetermined maximum pressure, whereby the press cannot be accidentally opened to cause injury to the operator.

Another object of the invention is to provide a press unit of the character described with means for cooling the mold sections between successive vulcanization periods, and thereby materially increasing the production output of the press in a given period of time.

Another object of the invention is to provide a press of the character described in which the vulcanized articles are quickly cooled to facilitate removal thereof from the press.

Another object of the invention is to provide an improved multiple press for the purposes de scribed and a single prime mover with means for operating the press from such prime mover.

A further object of the invention is to provide a press unit of the character described in which is obviated the use of flexible or other conduits for conveying heating fluid to the movable mold sections or supporting platens thereof.

Still another object of the invention is to provide in such presses simple effective means for causing a plurality of relatively movable platens to be operable to and from registry with each other substantially in parallel, and to be in stepped positions when the press is fully open.

Another object of the invention is to provide, in apparatus of the character described, improved means for facilitating cleaning of the mold sections.

These and other objects will be manifest from the following brief description and the accompanying drawings,

Of the accompanying drawings:

Figure 1 is a top plan view of a closed multiple press unit embodying the invention.

Figure 2 is a side elevation thereof, partly broken away and in section, as viewed from the right of Figure 1.

Figure 3 is a rear elevation thereof, partly broken away and in section.

Figure 4 is an end elevation, similar to Figure 2, but in an intermediate open position, parts being broken away and in section through the cavity members and supporting structure therefor.

Figure 5 is a cross-section taken on line 55 of Figure 1, but with the press in fully open condition.

Figure 6 is an enlarged detail view of the cam mechanism for guiding the movable mold memher to and from registry.

Figure 7 is a cross-section taken substantially 'on line 1-1 of Figure 6.

Figure 8 is a cross-section taken substantially on line 88 of Figure 4, illustrating the piping arrangements used for heating and cooling the cavity members.

Figure 9 is an enlarged detail cross-section of the latch mechanism shown at the upper left-hand portions of Figures 4 and 5, for releasably retaining the cavity member in its mold section.

Figure 10 is a cross-section taken substantially on line l0|0 of Figure 9.

Figure 11 is a schematic wiring diagram for the press.

Figure 12 is a conventional developed view of a timer cam, which initiates the various operations in the vulcanizing cycle of the press.

Referring to the drawings, the numeral l5 designates a suitable base frame for fixedly supporting a lower platen' l6, and above the latter,

arranged to be moved to and from superposed registering relation therewith and with each other, may be intermediate and upper platens l1 and I8, respectively. When the press is closed, an opening l9 extending through intermediate platen I! is arranged to communicate, at the vertically opposite faces of the platen, with cavities or

recesses

20 and 2! in the opposing faces of the upper and lower platens I8 and I6, respectively. This provides a single closed steam chamber, indicated generally at 22 in Figure 2.

Plates

23, 23 on opposing sides of the respective platens may have flat interengaging faces. Fixed to project slightly from one of such faces in each pair of plates 23, there preferably is a gasket 24 for contacting the face of the adjacent plate 23 to insure a tight fluid seal between the platens.

The three platens may be fabricated from sheet metal to form spaced walls 25, the latter being reinforced against the internal pressure of chamber 22 by means of stays or

braces

26, 25. This provides

hollow spaces

21, 21 in the platens completely to surround the chamber 22, these spaces being filled with suitable heat-insulating material 21 such as asbestos or asbestos composition, for insulating the chamber from the exterior.

Supported by the platens so as to be enclosed within chamber 22, when the press is closed, maybe a pair of molds 2B, 28, each comprising a lower female section 29 and an upper mating section 30.

.As best shown in Figure 5, the interior surfaces of the mold sections are shaped for forming vehicle seat cushions, indicated at 3|, 3|, and a series of spaced projecting elements 32; 32 are provided on the underside of each male' member for forming recesses in the bottom sides of the cushions to increase the flexibility and ridin comfort of the cushion.

The male mold sections are releasably supported at the undersides of the intermediate and upper platens l1 and I8, respectively, to permit swinging them downwardly when the press'is fully open, as shown in chain-dotted lines at the top of Figure 5, for the purpose of cleaning scale or other accumulations from the upper surfaces of the sections, thereby to maintain uniform vulcanizing heat at all sides of the molds. For this purpose, bars 34, 34, disposed at opposite sides of the mold sections may be pivoted on

pins

35, 35 extending from the end walls of the respective supporting platens IT and I8, and the forward ends of the bars may be releasably supported by latch mechanisms 35', 35, mounted onthe platens. The bars 34 are provided with longitudinally extending dove-tail slots 3b for receiving cooperating heads 37 of bolts 38 which extend through openings 39 in blocks 43, suitablylocated' on the male sections 30, to support the latter, nuts, 4 I, being threaded on the bolts at opposite sides. of the blocks for adjustably retaining the mold sections in the proper centered positions; By shifting the bolts 38 in slots 35 and adjusting nuts" 41 on the bolts, mold sections of a. wide range of sizes may be interchangeably mounted in the platens.

Each latch mechanism 35 may have a latch 42 received through a slot 43 in bar 34 and pivoted to the latter at 44, a spring 45 being extended between the latch and a m 46. on the bar 34, normally to urge a projection 42 on the latch into engagement with the top edge portion of a plate or lug 41 extending from the supporting platen, thereby to retain the upper or male section 30 of the mold in normal operating position in the platen. To release the latches 42'for swinging male sections about the pivots 35; an operator station-ed at the front of the press engages a suitable tool in an opening 48 in thedownwardly extending end of the latches and yieldingly swings the latches on pivots 44 to disengage th same from plates 41-, thereby allowing the sections to drop to positions for cleaning the top surfaces thereof, best shown'by chain-dotted lines in Figure 5.

For supporting the female sections 29 in platens It and I1 a flange 50 extending along the front end of each of said sections may be bolted at 5|, 5| to angle bars 52 fixed in the respective platens.

Rigidly secured to the end walls of said platens may be slotted bars 53, 53, similar to bars 34 which support the upper sections of the molds. for receiving

bolts

54, 54 adjustably secured in

blocks

55, 55 fixed on sections 29 adjacent the rearward corners thereof, these bolts 54 also being adjustable in the slots of bars 53 to accommodate sections of various sizes.

As best illustrated in Figure 8, the above described manner of supporting the upper and lower sections of the molds in the platens provides ample space between the molds and the in side walls of the platens for free circulation of vulcanizingor other medium about the same. For supplying vulcanizing steam under pressure to chamber 22,.a pipe 55 from a suitable source of supply (not shown) may terminate in a loop 56, a U-shaped portion 57 of which extends into recess" 21' of lower platen IE to emit the steam from a series of spaced openings 58 about the bottom of the pipe. A valv 59in pipe 55 may be automatically controlled by timer mechanism, subsequently tobe described in connection with the Wiring diagram, to circulate steam within chamber 22 when the pressis fully closed. A pipe fill communicates with adrain 6 lin the bottom of recess 2| of platen I6 for draining condensate from chamber 2 2.

For-removing the steam from chamber 22 after each vulcanizationperiod, and for cooling the molds and the vulcanized articles, a pipe 62, having spaced openings 63 therein, may be suitably supported within recess 21 of platen [6, the pipe 62 being connected to a suitable suction device (not shown) by a pipe 53-. A- valve'64 in pipe 63 may be controlled by the timer mechanism, to be described later, in coordination with steam valve 59 in pipe 55; This arrangement is such that after each vulcanization period, and while the press is still closed, valve 55 is automatically actuated to cut off the' steam supply to chamber 22, while valve 64 is actuated to apply substantial suction to the chamber, therebydrawing offthe steam and cooling the mold sections and thecontents thereof. A suitable check valve 65 in drain pipe prevents exhausted steam or cond'ensate' from being sucked back from pipe 63. Atthe start of a vulcanization period, suction may be applied in the closed chamber 22* for a few seconds simultaneously with injection of steam therein, to' eliminate air and' insure uniform circulation ofthe steam. It is obvious that suction may thus-be applied tochamber 22'before injection of steam thereto, for evacuating said chamber, and consequently th spaces between the registering mold sections.

Referring particularly to Figures 1 to '7, the intermediate platen I"! and upper platen 13 may be supported to be moved from the closed registering positions shown in' Figure 2, to intermediate parallel open positions, shown in Figure 4, and thence to the fully'open positions, as shown in Figure 5-, in which latter positions platen I? may be in parallel, rearwardly stepped, relation to lower platen l6, and upper platen 18 may be in rearwardly stepped relation to platen H and'tilted rearwardly thereofl This stepped fully open arrangement of thethree platens facilitates pour ing a liquid, such, as liquid rubber latex or other liquid rubber compounds used in manufacturing sponge rubber articles, into the

lower mold sections

29, 29 to levels indicated in chain-dotted lines at L, L.

To this end, extending upwardly from bas frame 15, at both sides and-rearwardly of the press, may be supporting

casings

66, 66 having laterally spaced

walls

61, 61.

Arms

68, 68 may be pivotally connected, at one end thereof, in casing 66, the free ends of the arms having pivoted thereto at 11, links 69 which extend downwardly to be pivotally connected at points substantially on the transverse center of the press to

pins

18, 18 fixed in the lower ends of plates 1|, 1|, suitably secured to the sides of intermediate platen I1 (see Figures 6 and 7). For pivoting arms 68 to casing 66 pins 12, 12 may be fixed in the ends of the arms to be journalled in bosses 13, 13 in the walls 61.

Arms

18, 14, arranged to be moved in parallelism with arms 68, may have

pins

15, 15 fixed in one end thereof to journal in bosses 16 in Walls 61 of the casing 86, preferably at points upwardly and rearwardly of pins 12. The free ends of arms 14 may have pivoted thereto at 11, 11, downwardly extending

links

18, 18, similar to links 69 on arms 63, which are pivotally connected to eccentric extensions 19, of

pins

88, 88, fixedly retained in plates 8|, 8| by means of set screws 92, the plates 6I being suitably secured to the sides of upper platen I8 so that pivots 19 are in substantial vertical alignment with pivots 18 of platen I1 when the platens are in registry. The positions of pins 15, relative to pins 12, are predetermined so that arms 14 will be of such length to swing upper platen I8 upwardly and rearwardly to the relative position thereof shown in Figure 5, in which there is ample clearance for pouring liquid L into the mold section 29 carried on platen For adjusting upper platen I8 vertically on supporting links 18, accurately to register the same relative to the other platens, and to regulate the amount of squeeze pressure applied to the registering faces of the mold sections, eccentric extensions 19 on pins 88 may be provided with squared heads 19 engageable by a suitable tool (not shown), after set screws 82 have been temporarily loosened to change the centers of the pins relative to the centers of the eccentric extensions.

For maintaining the

arms

68 and 14 in parallelism in all positions thereof, links 84, 84 are pivotally connected at opposite ends thereof to pins 85 in arms 14 and to pins 86 in bifurcated lugs 81 on arms 68, pivots 15 and 85 being equidistant from pivots 12 and 86, respectively, and pivots 15 and 12 being equi-distant from

pivots

85 and 86, respectively, so that lines joining these pivot points always form parallelograms.

Pitmans

88, 88, preferably are pivotally connected at one end to downwardly extending projec'tions 89 on arms 14, intermediate pins 15 and 11, and the other ends thereof are pivotally connected at 98, 98 to crank arms 9|, 9I, operable to swing the

arms

68 and 14, on pivots 12 and 15, in parallelism for opening and closing the press. The cranks 9I may be secured on

shafts

92, 92, journalled in

bearings

93, 93 on frame I5, and driven through a suitable reduction gearing 94 by a reversing type motor 95.

During the final closing and initial opening movements of the press, it is desirable to move intermediate platen I1 and upper platen I8 vertically in parallelism relative to each other and relative to lower platen I6, for accurate registering of the

mold sections

29, 38, and to separate vulcanized articles from the mold sections without damaging the same. For thus guiding intermediate platen I1, between the positions thereof shown in Figures 2 and 4,

plates

96, 96, suitably secured to the sides of lower platen I6, may have upwardly extending bifurcated portions 91, in spaced relation to the sides of intermediate platen I1, providing vertical guiding or cam surfaces 98, 98 for

rollers

99, 99, carried by pins 18 on platen I1. Similarly, plates III on upper platen I8 may have downwardly extending bifurcated portions I88, I88, providing vertical guiding or cam surfaces I8I, I8I, for pairs of vertically aligned rollers I82, I83, which are journalled on pins I84, fixed between off-set portions 1-I of plates H and spacer plates I on the sides of platen I1 (see Figures 7). Plates H are slightly narrower than the diameter of rollers I82, I83, to clear the cam surfaces I8I of extension I88.

As cranks 9| are operated to swing

arms

68 and 14 on pivots 12 and 15, toward the fully open positions thereof, rollers 99 on pins 18 follow upwardly and rearwardly curving cam surfaces on the rear prongs 96 of plates 96, with a slight drag to prevent links 69 from swinging on the pivots 11, and therefore preventing lateral swaying of intermediate platen I1. Platen I1 is maintained in parallel with lower platen I6 at all times by means of a system of links operating in cooperation with arms 68, the rollers carried by plate 1| being effective for this purpose only during the initial opening and final closing movements of the press, as previously described. For this purpose arms I81, equal in length to arms 68, are pivoted on pins I98 to the inner walls 61 of casing 66, rearward extensions I89 and I I8 on arms 68 and I81, respectively, having links II 3 pivotally connected thereto at I I I and I I2 to maintain arms I81 in parallelism with arms 68, in all positions of the latter. Links of the same length as links 69 on arms 68 are pivoted at H5 to the forward ends of arms I81 and extend downwardly, pivotally to connect pins H6 extending from the sides of intermediate platen I1 at points rearwardly of the center of the press. The arrangement is such that in all positions of arms 68 and I81 the links 69 and II 4 are maintained in parallelism, and therefore platen I1 is at all times prevented from swinging on the pivots 18 to maintain it in parallelism with respect to lower platen I6.

The inner prongs 8 l of plates 6i preferably are shorter than outer prongs 8 I, so that as the arms 14 carry upper platen 58 toward the fully open position thereof, shown in Figure 5, prongs 8| will disengage rollers I82, I 83, while the top rollers I82 will continue to engage cam surfaces I8l on forward prongs Si to cause upper platen to tilt on pivots "I9 on links 18. As arms 19 approach the fully open position thereof, adjusting screws II1, suitably threaded in bosses II8 on the forward ends of the arms, are arranged to engage the rear edges of links 18 to limit rearward swing of the latter on pivots 19 and thereby hold the platen at a predetermined angle to the horizontai.

Retained between tubular housings II9, fixed on arms 14, and pins H9 in the lower ends of links 18, may be compression springs I28, yieldingly to urge the links outwardly of the arms 14 to prevent jerking movement of the platen, as it moves in either direction between the positions thereof shown in Figures 4- and 5. The tension of springs I28 may be adjusted by means of screws I 2| threaded through the ends of the housings and engaging discs I22, against which the springs abut. Stop pins I23 are provided on the platens I1 to be engaged by the outer edges of prongs 8I to prevent springs I28 from urging. the same out of. engagement with rollers I02. and. I03; in the upper positions of platens I1 and. I8, 1 1

To obviate binding of links 04' between the arms Hand 68 when. the press is closed, the openings 86P-in the. lower ends of the links are elongated. to. allow a slight. relative movement of" the arms. In order to take up this slack.while the press is opening andclosing, spiral springs I24, enclosed in: casings I25, I25, have the inner ends thereof engaged in slots I26 in the. outer ends of shafts "I2 and 15, and the outer ends attached to pins I21 in casings 66 (see Figure 2). This arrangement of the springs I24 also acts to steady the swinging movement of arms 08 and 14 in either direction, and relieves strain on motor 95 when the same is operated to open the press.

The operation of the press for a complete vulcanizing cycle will now be described with reference to the schematic wiring diagram, shown in Figure 11. In this description it is to be assumed that initially the press is in the fully open position shown in Figure 5, with the previously vulcanized seat cushions 3I removed from mold sections 29, and that new batches of treatedliquid rubber latex L, or the like, used in making sponge rubber articles, have been poured into the

female mold sections

29, 29, as indi cated in chain-dotted lines.

Referring particularly to Figure 11, the operatcr, by pressing the start button, momentarily closes contacts Ia, to connect the pilot circuit P1-P3, on one side of the line through contacts a-c on a pressure-operated switch S, and on the other side through I-b on a pressoperated limit switch C1, thereby energizing a forward coil F1. Energizing coil F1 closes mechanically interlocked switches F in the power circuit to actuate the motor 95 to close the press. Switch C1 is normally closed across I-b by action of a cam I28 on driving shaft 92, when the press is fully open, but as soon as the press starts to close the cam opens I--b and closes b--2, which remains closed until the press.

completes a cycle of operation and is again in fully open condition. As soon as the start button is released the circuit through I-a is broken, but in the meantime, actuation of coil F1 closes a sticker switch FS, and a press-operated cam I29 on drive shaft 92 closes switch 02. thereby closing a new circuit from P1, through the stop button, switch C2, the reverse button, sticker switch FS, coil F1, and pressure switch S, to P3, thus keeping coil F1 energized, and consequently continuing the operation of motor 55 to close the press.

Previously to pressing the start button, the connection across b-I on switch C1 maintains a latching relay LR,1 in energized condition to hold switches L1 and L2 normally closed, and switches L3 and L4 normally open, thus maintaining the timer mechanism in inoperative condition whenthe press is fully open. When b-2 is closed by the closing movement of the press, as described above, the relay LR1 is de-energized to open switches L1 and L2- and close switches L3. and L1, thereby closing a circuit across P1--P3, through. b-2 on switch C1, switch L3, and timer motor T, to start the latter. This starts rotation of a disc cam I30 to actuate a series of mercury switches M1, M2, LIB,.1VI4 and M5 in predetermined sequence, as will be described.

When the. press is fully closed cam I29 on drive shaft. 92 again opens switch C2, thereby deenergizing forward coil F1 to open the interlocked switches F and stop motor 95, and at the same time opening sticker switch FS.

As the cam I30 continues to rotate for the curing cycle, switch M5 is actuated at point W on the cam (see Figure 12) to close a circuit through P1P3, b--2, M5, and L4, to energize coils ST1 and V. This actuates vent valve 64 and steam valve 59 (Figure 8), simultaneously to draw air from chamber 22 and to inject steam therein for a few seconds to assure good circulation of the steam. This preferably takes place after the liquid rubber L in the molds has jelled or set a sufiicient length of time to expand and fill the mold cavities, by virtue of chemical agents mixed with the liquid.

At point X on. cam I30 switch M5 opens to (la-energize coil V. A device in coil mechanism V thereby closes vent valve 64 to stop suction or venting of air from chamber 22, and a lock in coil mechanism ST1 holds steam valve 59 open to maintain the steam pressure in the chamber.

At Y on cam I30 switch M1 closes to energize coil LRz, thereby closing switches L1, L2 and opening switches L3 and L4, the steam in chamber 22 remaining on. Just before switch L3 closes, switch M3 is actuated by cam I30 to maintain the circuit through timer motor T to keep cam I30 rotating to the end of its cycle. Switch M2 is actuated to close at point Z on cam I30, to-close a circuit P1--P3, b--2 of switch C1, latching relay switch L1 and mercury switch M2, thereby energizing a coil STz to close valve 59 and shut off the steam supply to chamber 22 (Figure 8). At the same time a circuit is closed through relay switch L2, energizing coil V to open valve 64 and applying suction through pipe 52. This draws all steam from the chamber 22 and substantially cools the mold parts and vulcanized articles 3|, before the press opens.

It is understood that during the curing period the steam in press chamber 22 actuates safety switch S to maintain the press motor operating circuit open across ac, and closes a circuit across d--c, thereby energizing signal lamp S2. Hence, the operator will be warned that the press is about to open, when the steam pressure is vented from chamber 22, because the circuit across d-c will be opened and signal S2 will go out.

When timer cam I30 reaches the end of the curing cycl thereof, mercury switch M3 is opened to stop. timer motor T. At the same instant, switch M4 is momentarily closed to make a circuit through pilot P1-P3, b-2 of switch C1, relay switch L1, mercury switch M4, coil F1 and safety switch ac. This-energizes coil F1 again to close switches F in the power circuit to start motor for opening the press. Before the press starts to open, switch Mz'is opened allowing the device in coil V to close vent valve E i to stop the suction from chamber 22. As soon as the press starts to open, the circuit through switch C2 and the reverse button keeps motor 95 running until cam I29 stops'the motor in the fully open condition of the press.

When the press reaches the fully open position (Figure 5), switch C2 is opened by cam I29 at the rear of the press to stop motor 95, and switch C1 is actuated by cam I28 to close a pilot circuit across. b-I, thereby to hold latching relay coil LE1 in the in position, with switches L1 and L2 closed, and switches L3 and L4 open, ready for starting a new cycle of operation of the press, as described.

The safety switch S is of known type having a conduit I39 which communicates with the interior of chamber 22 of the press (see Figure 3). Should an attempt be made to open the press while steam, above a predetermined degree of pressure as low as a fraction of a pound per square inch, remains in the steam chamber, switch S will be actuated to open any of the motor driving circuits to prevent motor from running. Switch S also closes contacts dc to flash a signal at S2 to give warning that there is steam pressure in chamber 22. Of course, under normal conditions the steam will always be vented from chamber 22 before the press opens, switch S being provided to prevent accidental opening of the press before the pressure in the chamber is below a safe level.

Motor 95 may be reversed at any time, when there is no pressure in chamber 22, by pressing the reverse button, closing a circuit through pilot P1P3, the stop button 3e on the reverse button, reverse coil R1, and safety switch S, the circuit being held after the motor is started, through reversing sticker switch RS. Energizing of coil R1 closes mechanically interlocked switches R in the power circuit to operate motor in reverse. The reversing circuits have no effect on the timer circuits.

The general operation of the press is readily understood in connection with the foregoing description of the wiring diagram. Briefly, it is the usual practice in manufacturing plants to arrange a battery of presses to open in sequence, according to the settings of the press timers, the operator or operators moving from one press to another as they open, stripping the finished cushions 3| from the upper mold sections, and, pouring fresh batches of liquid rubber compound L into the lower mold sections 29.

After the cured cushions 3|, 3| have been removed from the open press, as shown in Figure 5, the operator pours the liquid L in the cavities of lower mold sections 29, the latter operation being greatly facilitated by the fact that the platens I6, I1 and iii are in spaced rearwardly stepped relation. Next, he presses the sta button (Figure 11) which, through various instrumentalities shown in the wiring diagram, starts motor 95, to close the press. The motor swings cranks 9I in clockwise direction (Figure 2) causing link 88 to swing arms I4 and 63, carrying platens I8 and I1, respectively, downwardly in parallelism, the intermediate platen II being constantly maintained in horizontal condition to prevent spilling of the liquid L from mold section 29 mounted therein.

As the platens IT and I8 are moved toward intermediate positions thereof, shown in Figure 4, the cam surfaces on plates 99 at the sides of lower platen I 6, and on plates 8|, at the sides of the upper platen I8, engage rollers 99, I92, and I93 carried by intermediate platen IT, to guide platens I7 and I8 in vertically superposed parallelism with each other and with lower platen I6. Continued downward movement of platens I1 and I 8 to the fully closed positions, shown in Figure 2, brings the adjacent faces 23 of the respective platens into registering relation, the respective pairs of

mold sections

29 and 30 then also being in registering relation. When the press reaches the fully closed condition, cam I 29 on driven shaft 92 actuates switch C2 to stop motor 95, the timer motor T in the meantime having been started to operate the timer circuit for a curing cycle.

For a short period before the actual curing process begins, the batches of liquid compound L are allowed to jell or set, chemicals of known type in the compound causing expansion of the batches so as to fill all parts of the mold cavities. For a few seconds after the end of the jell period, the timer simultaneously actuates

valves

59 and 64 on steam supply line 55 and suction line 63, respectively, to vent all air from press chamber 22 and insure free circulation of the steam about the

molds

28, 28. The timer then closes vent valve 64 and allows the valve 59 to remain on for a sufficient period of time to cure contents of molds 28 to the shape of the mold cavities.

At the end of the cure the timer closes steam valve 59 and opens suction or vent valve 69, thereby venting the steam from chamber 22, through

pipes

62 and 63. The suction is applied in chamber 22 for a short period after the steam is vented for the purpose of cooling the interior chamber, and hence substantially cooling molds 28 and the sponge rubber cushions 3I contained therein. When the parts have been allowed to cool a suflicient length of time to facilitate handling the cured cushions 3|, for example, vent valve 64 is closed by the timer. The latter then starts press motor to continue swinging cranks 9| in clockwise direction (Figure 2), for swinging arms 68 and I4 upwardly in parallelism, thereby carrying the platens I! and I8, initially in vertically superposed parallelism with the horizontal, and then swinging them rearwardly to the stepped positions thereof shown in Figure 5. In the latter positions platen II ismaintained in parallelism with the horizontal by the parallelogram linkages, indicated generally at H, and platen I8 is tilted rearwardly by action of forward cam surfaces I M on plates 8|, riding on top rollers I02 carried by the intermediate platen I'I. When the press reaches this fully open condition the press-operated limit switch C2 is actuated by cam I29 on shaft 92 to stop motor 95, and the similar cam I28 on shaft 92 actuates limit switch C1 to reset the timer circuit for a succeeding cycle of operation, timer motor T in the meantime having stopped with timer cam I39 set in proper position for this purpose. The press remains fully open until the start button is again pressed.

The rearwardly stepped arrangement of the three platens permits the finished cushions 3! to be readily stripped from the upper or male mold section 39, as well as facilitating ready access for pouring liquid L into the cavities of the female mold section 30, on both the lower and intermediate platens I6 and I1. Since the mold sections are substantially cooled by the venting operation before the press opens, as previously described, the liquid L may be poured'substantially as soon as the press is opened, thereby effecting a considerable saving in time usually wasted in waiting forthe mold parts to cool. It should be noted that since the intermediate platen I1 is closed in parallelism with the horizontal and with a steady movement due to the action of spiral springs I24 connected to the platen arms 68 and Hi, the liquid L will not be spilled from the female mold section 29.

Modifications of the inventions may be resorted to without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

l. A press of the class described, comprising a plurality of members relatively movable into registry with each other, said members having recesses therein to :formaclosed chamber when the members are in registry, mating mold sections, means for supporting said mold sections on said members to be in mating relation within said chamber when closed, and releasable means 'for securing said sections against pivotal movement on said members, said releasable means being releasable to permit swinging said pivoted sections outwardly of the supporting members thereof when the press is open.

2. A press of the class described comprising a plurality of relatively movable press members adapted to be in superposed registering relation when the press is closed, said members being recessed to form a single closed chamber in the closed position thereof for containing fluid heating medium, a series of mating upper and lower mold sections mounted on said members to provide a plurality of superposed article-forming molds within said closed chamber, means for supporting said members to berelatively movable between said closed position of the press and in open position thereof in which all said members are in vertically spaced and substantially transversely-stepped relation, said stepped relation of the members facilitating pouring'articleforming material into said lower mold sections, means for moving said supporting means to open and close the press, and means for maintaining said lower mold sections substantially horizontal in all positions of said members for preventing spilling of article-forming material therein.

3. A press of the class described, comprising upper and lower press members relatively movable vertically into registrywith each other, said members having recesses therein to form a single closed chamber when the members are in registry, mating upper and lower mold sections supported insaid members to be in mating relation when thepress is closed, the upper moldsection being mounted to be shiftable downwardy of the upper member for cleaning the upper surfaces of the upper mold section when the press is open, and quickly releasable means for normally securing said upper mold section against shifting downwardlyof said upper member.

4. A press of the class described, comprising upper, lower and intermediate members-arranged to be in superposed registering relation'when the press is closed, a shiftable support forsaid upper member, ashiftable support for said intermediate member, said shiftable supports being relatively shiftableto move the members thereon from said closed position of the press to an open position in which all of said members are in spaced-apart, substantially stepped relation, means for shifting said supports to open and close the press, and means for maintaining said intermediate member in parallelism with said lower member between the open and closed positions thereof, said stepped relation of the members'being such that at least a substantial portion of each member is unobstructed from above by the member or members above it.

5. A vulcanizing press of the class described comprising a relatively fixed lower mold member and relatively movable upper and intermediate mold members arranged to be in superposed registering relation when the press is closed, separate arm members forsupporting said movable mold members to swingthe same in separate upwardly and rearwardly extending arcs-about fixed pivots, connectingimeans pivoted-at spaced points to said arm members, and power means connected to one of said arm members for swinging both said arm members to open and close the press, said arm members being proportioned and arranged with respect to each other for swinging said movable mold members in said separate .arcs from said closed positions thereof to positions in which all of the mold members are in spaced apart, substantially stepped relation.

6. -A vulcanizing press of the class described comprising a. relatively fixed lower mold member and relatively movable upper and intermediate mold members arranged to be in superposed registering relation when the press is closed, separate arm members for supporting said movable mold members to swing the same in separate upwardly and rearwardly extending arcs about fixed pivots, connecting means pivoted at spaced points to said arm members, power means connected to-one of said arm members for swinging both said arm members to open and close the press, said arm members being proportioned and arranged with respect to each other for swinging said movable moldmembers in said separate arcs .from said closed positions thereof to positions in whichall of the mold members are in spaced apart, substantially stepped relation, and means for maintaining said intermediate mold member in parallelism with said lower mold member between theopen and closed positions thereof.

7. A vulcanizing press of the class described comprising a relatively fixed lower mold member and relatively movable upper and intermediate mold members arranged to be in superposed registering relation when the press is closed, a relatively fixed support rearwardlyof the press, an arm member pivoted on said fixed support, said intermediate mold member being supported on the free end of said arm member to swing therewith in an upwardly and rearwardly extending arc, a relatively longer arm member pivoted on said fixed support, said upper mold member being pivotally supported on the free end -of said longer arm member to swing therewith in aseparate upwardly and rearwardly extending arc, a link pivoted at spaced points to said arm members to connect the same, power means connected to one of said arm members for swinging both said arm members to open and close the press, the fixed pivot of said longer arm member being spaced upwardly and rearwardly of the fixed pivot of the shorter arm member and the pivotal connections of said link to said arm members being arranged relative to said fixed pivots whereby said power means is operable to swing said arm members to move said intermediate and upper mold members in said arcs to positions in which all of said mold members are in upwardly spaced, rearwardly stepped relation, and means for maintaining said intermediate mold member in parallelism with said lower mold member.

8. A vulcanizing press of the class described comprising a relatively fixed lower mold member and relatively movable upper and intermediate mold members arranged to be in superposed registering relation when the press is closed, a relatively fixed support rearwardly of the press, an arm member pivoted on said fixed support, said intermediate mold member being supported on the free end of said arm member to swing therewith in an upwardly and rearwardly extending arc, a relatively longer arm member pivoted on said fixed support, said upper mold member being pivotally supported on the free end of said longer arm member to swing therewith in a separate upwardly and rearwardly extending are, a link pivoted at spaced'points to said arm members to connect the same, power means connected to one of said arm members for swinging both said arm members to open and close the press, the fixed pivot of said longer arm member being spaced upwardly and rearwardly of the fixed pivot of the shorter arm member and the pivotal connections of said link to said arm members being arranged relative to said fixed pivots whereby said power means is operable to swing said arm members to move said intermediate and upper mold members in said arcs to positions in which all of said mold members are in upwardly spaced, rearwardly stepped relation, and means for maintaining said intermediate mold member in parallelism with said lower mold member, the pivots of said link between said arm members being in substantially parallelogram relation with respect to said fixed pivots of the arm members.

9. A vulcanizing press of the class described comprising a relatively fixed lower mold member and relatively movable upper and intermediate mold members arranged to be in-superposed registering relation when the press is closed, a relatively fixed support rearwardly of said mold members, an arm member pivoted on said fixed support, a link element pivotally depending from the free end of said arm and pivot ally connected at its lower end to said upper mold member to support the same, another arm member pivoted on said fixed support, a link element pivotally depending from said other arm and pivotally connected at its lower end to said intermediate mold member, a link element pivotally connected at opposite ends to said arm members, said arm members being shiftable on the fixed pivots thereof to swing said movable mold members in separate upwardly and rearwardly extending arcs about the fixed pivots of the arm members, and power means for moving said arm members, said arm members being proportioned and arranged with respect to .each other to swing said movable mold members in said separate arcs from said closed positions thereof to positions in which all of the mold members are in vertically spaced, substantially rearwardly stepped relation.

10. A vulcanizing press of the class described comprising a relatively fixed lower mold member and relatively movable upper and intermediate mold members arranged to be in superposed registering relation when the press is closed, a relatively fixed support rearwardly of said mold members, an arm member pivoted on said fixed support, a link element pivotally depending from the free end of said arm and pivotally connected at its lower end to said upper mold member to support the same, another arm member pivoted on said fixed support, a link element pivotally depending from said other arm and pivotally connected at its lower end to said intermediate mold member, a link element pivotally connected at opposite ends to said arm members, said arm members being shiftable on the fixed pivots thereof to swing said movable mold members in separate upwardly and rearwardly extending arcs about the fixed pivots of the arm members,

power means for moving said arm members, said arm members being proportioned and arranged with respect to each other to swing said movable members in said separate arcs from said closed positions thereof to positions in which all of the mold members are in vertically spaced, substantially rearwardly stepped relation, means for maintaining said intermediate mold member in parallelism with said lower mold member during movement thereof, and cooperating guide means on said relatively movable mold members operable when the same are between intermediate and closed positions for maintaining the upper mold member in parallelism with the intermediate mold member.

11. A vulcanizing press of the class described comprising a relatively fixed lower mold member and relatively movable upper and intermediate mold members arranged to be in superposed registering relation when the press is closed, a relatively fixed support rearwardly of said mold members, an arm member pivoted on said fixed support, a link element pivotally depending from the free end of said arm and pivotally connected at its lower end to said upper mold member to support the same, another arm member pivmed on said fixed support, a link element pivotally depending from said other arm and pivotally connected at its lower end to said intermediate mold member, a link element pivotally connected at opposite ends to said arm members, said arm members being shiftable on the fixed pivots thereof to swing said movable mold members in separate upwardly and rearwardly extending arcs about the fixed pivots of the arm members, power means for moving said arm members, said arm members being proportioned and arranged with respect to each other to swing said movable members in said separate arcs from said closed positions thereof to positions in which all of the mold members are in vertically spaced, substantially rearwardly stepped relation, and cooperating guide means on said relatively movable mold members operable when the same are between intermediate and closed positions for maintaining the upper mold member in parallelism with the intermediate mold member.

RUPERT G. MINNS. HENNING T. TORN'BERG.