US3759649A

US3759649A - Multiple-section molding press

Info

Publication number: US3759649A
Application number: US00223506A
Authority: US
Inventors: C Tyler
Original assignee: Tyler Machinery Co Inc
Current assignee: Tyler Machinery Co Inc
Priority date: 1972-02-04
Filing date: 1972-02-04
Publication date: 1973-09-18
Anticipated expiration: 1990-09-18

Abstract

A multiple-section molding press having molding press sections arranged in aligned vertical and horizontal rows. Each section has a fluid pressure-operated platen. A vertically movable horizontal elevator platform member is adapted to receive box molds from a conveyor, and the box molds can be moved along the platform member so as to be manually positioned adjacent any of the vertical rows of press sections. A bank of illuminated control switches is provided for the sections. The elevator platform is provided with pushers and ejection devices aligned with the respective vertical rows. Automatic vertical positioning circuits are provided for the platform member, as well as press cycling circuits, operating in response to the actuation of a selected illuminated control switch to place a mold box at the level corresponding to the selected illuminated switch. The associated pusher automatically moves the mold box into press position and simultaneously ejects a previously compressed mold box therefrom onto the discharge side of the platform so that it is engaged by the associated ejection device. The platform returns to conveyor level. A respective timer is provided to control the action of each of the press sections and to indicate completion of a press cycle.

Description

[ 1 Sept. 18, 1973 MULTIPLE-SECTION MOLDING PRESS [75] Inventor: Claude T. Tyler, Warsaw, Ind.

[73] Assignee: Tyler Machinery Co., Inc., Warsaw,

, Ind.

22 Filed: Feb. 4, 1972 [21] Appl. No.: 223,506

[52] US. Cl. 425/145, 425/169, 425/156,

7 425/234, 425/33s [51] Int. Cl..;.... 1130b 7/02, 1330b 15/16, 329g 7/02 [58] Field of Search 425/333, 339, 340, 425/341, 455, 394, 397, 234, 145

[56] References Cited UNITED STATES PATENTS 3,157,910 11/1964 Schlipphak 425/254 3,206,800 9/1965 Muller 425/339 X 3,611,482 10/1971 l-lutz 425/338 X 2,543,582 2/1951 Lyijynen 425/339 X 2,831,213 4/1958 Klarmann ct al 425/339 3,170,189 2/1965 l-lutter 425/339 3,368,242 2/1968 Loewenfeld et al. 425/339 X 3,517,610 6/1970 Siempelkamp.. 425/341 X 3,551,944 l/1971 Muller 425/340 Primary Examiner- J. Howard Flint, Jr. Attorney-Hyman Berman et al.

[ I ABSTRACT A multiple-section molding press having molding press sections arranged in aligned vertical and horizontal rows. Each section has a fluid pressure-operated platen. A vertically movable horizontal elevator platform member is adapted to receive box molds from a conveyonand the box molds can be moved along the platform member so as to be manually positioned adjacent any of the vertical rows of press sections. A brink of illuminated control switches is provided for the sections. The-elevator platform is provided with 'pushers and ejection devices aligned with the respective vertical rows. Automatic vertical positioning circuits are provided for the platform member, as well as press cycling circuits, operating in response to the actuation of a selected illuminated control switch to place a mold box at the level corresponding to the selected illuminated switch. The associated pusher automatically moves the mold box into press'position and simultaneously ejects a previously compressed mold box therefrom onto the discharge side of the platform so that it is engaged by the associated ejection device. The platform returns to conveyor level. A respective timer is provided to control the action of each of the press sections and to indicate completion of a press cycle.

O00 0 '000 0000 000 000 00 0000 Dog 0000 PATENTED SEN 8 I973 SHEET 1 0F 8 PATENTEU SEP 1 8 I975 SHEEI 8 [1F 8 PATENIED SEPI 81973 SHEEI 7 BF 8 .m m WUx-Q pacity, and which ishighly automated.

, I I MULTIPLE-SEGTION MOLDING PRESS This invention relates to pressure molding devices, and more particularly to improvements in multipleplaten presses for use in molding plastic parts.

A main object of the invention is to provide a novel and improved multiple-section platen press which is relatively simple in construction, which has a high ca- A further object of the invention is to provide an improved multiple-section platen press for making plastic foam castings and for makingvarious other types of plastic castings having sizable face areas relative to ing' height.

A still further object of the invention is to provide an improved multiple-section platen press having elevator means for transferring mold boxes to the proper height to be inserted beneath an available platen, the elevator arrangement being such that it returns automatically to FIG. d is a fragmentary transverse vertical crosssectional view taken substantially on the line d-d of FIG. 2, showing the rear, or discharge, side of the multiple-section molding press of FIG. I;

FIG.'5 is an enlarged fragmentary horizontal cross sectional view taken substantially on the line E-fi of FIG; 2;

FIG. 6 is a vertical cross-sectional view taken substantially on the line 6-45 of FIG. 5;

FIG. 7 is a partial schematic diagram showing the fluid circuit of one of the press sections of the multiplesection molding press of FIG. I; and

FIGS. ha and 8b together constitute an electrical wiring diagram showing the electrical connections of the electrical components associated with uppermost, left end press section of the multiple-section molding press of FIG. I, and typifying the electrical circuits employed for all of the molding press sections of the assembly.

The rapidly growing field of foam castings as replace- 0 ments for many wood parts or parts made of other realtively expensive materials calls for suitable apparatus for retaining the foam securely while the chemicallygenerated heat therein expands the foam to till a mold box. If the casting has a substantial face area, relative 5 to depth, this retention can often best be done by employing a platen press. A platen press is very satisfacpliedsubstantially uniformly over the platen surface.

normal conveyor height. so that mold boxes can be supplied from a feed conveyor by simply rolling the mold boxes onto the elevator platform where the mold boxes can be properly positioned for feeding beneath available platens, and whereby processed mold boxes can be conveniently moved onto a receiving conveyor for further processing.

A still further object of the invention is, to provide an improved multiple-section molding press employing molding press sections of the pressure-vacuum pod type, the sections being arranged in aligned vertical and horizontal rows, and automatic elevator means being provided to automatically place a mold box at the proper level corresponding to an available molding press section, the elevator member automatically returning to normal conveyor height, thereby greatly faciliting the supplyof mold boxes to the apparatus and the removal of compressed mold boxes therefrom, the apparatus providing a considerable saving in labor in the handling of the mold boxes and providing a relatively high capacity for processing mold boxes therethrough because of its time-economizing features.

Further objects of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

F101 is a perspective view showing a typical multiple-section molding press assembly constructed in accordance with the present invention;

FIG. 2 is an enlarged frgmentary front elevational view, partly in vertical cross-section, of the right side portion of thernultiple-section molding press assembly shown in FIG. 1;

FIG. 3 is afragmentary transverse vertical cross-- sectional view, taken substantially on the line 3-3 of FIG. 2, showing the front, or receiving, side of the multiple-section molding press;

At the present time, it appears that a pressure of -20 to 30 lbs. per sq. inch on'the mold box is adequate to resist the foaming action.-

Wherethere is a requirement for a substantial vol- ,ume of production, a-corresponding large number of platen presses is required, and these must be employed in an organized manner in view of the fact that poured foam must be placed under pressure with in about 1 min.,' the pouring time being only a few seconds, and whereas the curing time under preddure is of the order of several minutes. A prime purpose of the present invention is to provide an apparatus embodying a substantial number of individual platen press assemblies embodied in a compact assemblage with provision 5 being made to take care of the necessay timingrequirements of properly pouring, compressing and curing foam castings of the type above mentioned and insuring efficient utilization of the large number of platen press assemblies provided in the apparatus.

A unique characteristic of the present invention is the provision of vertically stacked individual platen press assemblies with an automatic elevator system to move mold boxes to the proper level corresponding to available platen press assemblies. Another unique feature of the present invention is the alternate use of pressure and vacuum in the pressure pods of the'platen press assemblies. In each platen press assembly, vacuum is employed to raise the associated platen to thus permit instant movement of a mold box into the press assembly for subsequent compression by the platen. This feature enables the apparatus to occupy a minimum amount of vertical space, which is of considerable importance because a substantial number of rows are 5 required to provide the necessary production capacity and this number is limited by ceiling height factors.

Another unique feature of the present invention'is the location of the pressure. pod elements the framework immediately above the platen. This feature provides a substantial reduction in vertical height requirements, as well as allowing suitable distribution of load carrying members within the framework of the apparatus so as to provide most efficient utilization of the framing and to minimize local deflections of its members.

Still another important and novel feature of the present invention is the provision of an elevator system which always returns automatically to the same elevation; namely, on the in feed side to the elevation corresponding to that of the input conveyor, thus enabling an operator to simply roll a newly filled mold box to the proper position, as indicated by a signal lamp on the control panel, whereas on the output side of the machine, the elevator automatically returns to the proper elevation which corresponds to that of the receiving conveyor on which a mold box containing a cured casting can be rolled onward in the plant for de-molding and further processing. A still further interesting and unique feature of the apparatus of the present invention is the ability of easily enlarging the machine so as to add additional platen press assemblies, add the required longer elevator screws, and easily reassemble the machine with its substantially increased production capacity.

As will be presently described, the use of the elevator member provides considerable economy in time and reduction in required physical labor. The elevator also is provided with powered pusher mechanisms which push the mold boxes into press positions in their associated platen press assemblies while at the same time starting finished molds out of the assemblies on the opposite side. The elevator portion of the apparatus is likewise provided with powered rollers which engage the emerging mold boxes and carry them out the remaining necessary distance on the exit side of the assembly. An out feed operator is then able to roll the mold boxes along the elevator in a longitudinal direction; namely, at right angles to the movement of the mold boxes into and out of the platen press assemblies. As above mentioned, the elevator automatically returns its home" position. At this home elevation its surface registers with the plant conveyor and pouring station elevations. Also, in this home" position the elevator registers with the elevation of one of the horizontal rows of platen press assemblies in the machine.

Referring to the drawings, generally designates an improved multiple-section molding press constructed in accordance with the present invention. The assembly 20 is provided with an upstanding rigid framework having a pair of transversely extending supporting

base angle bars

21,21. Perpendicularly secured to the bottom angle bars 21,21 is a rectangular box-shaped bottom frame structure comprising front and rear longitudinally extending vertical plates 22 connected by transversely extending vertical end plates 23 rigidly secured thereto. Rigidly secured on the top edges of the

plates

22 and 23 is a horizontal support plate 24, employed as the mold box supporting plate for the lowermost horizontal row of platen press assemblies, presently to be described. The frame structure is provided at its top portion with a similar longitudinally-extending box-like structure comprising front and rear longitudinally extending vertical plate members 26 connected at their ends by transversely extending vertical plate members g7, A pair of vertical frame bars 28,28 are rigidly connected at the top and bottom ends respectively to the

transverse plate members

27 and 23 at the opposite ends of the main supporting frame. A horizontal top cover plate 29 is secured rigidly to the top edges of the

plates

26 and 27 at the top portion of the main supporting frame. Depending bracket members 30 are rigidly secured to the opposite end portions of the bottom plate members 22 and are secured in the transverse angle bars 21.

The main supporting frame also includes a plurality of uniformly spaced rectangular box-like platforms similar to that defined by the

top plate members

26, 27 and 29, said additional platforms being uniformly spaced between the top structure defined by said

members

26, 27 and 29 and the bottom box-like rectangular fixed structure defined by the

plate members

22, 23 and 24. Thus, the intermediate fixed horizontally extending platform structures comprise longitudinally extending front and rear vertical plate members 26 and transverse vertical end plate members 27, longitudinally extending horizontal plate members 24 being rigidly secured to the top edges of the

plate members

26 and 27. The top horizontally extending plate member 29 is similar to the plate members 24 except that it is provided with upstanding bearing brackets 31 rotatably supporting a horizontal shaft 32 for a purpose presently to be described.

In the typical embodiment illustrated in the drawing and described herein, there are five box-like structures spaced above the bottom box structure, defining five horizontal press spaces. The box structures above each of said spaces are further provided with internal longitudinally extending rectangular central tubular members 33 rigidly secured at their top walls to the

horizontal plate members

29 or 24 and rigidly secured at their opposite ends to the transverse plate members 27. Rigidly secured transversely between the front and rear vertical plate members 26 of each of the fixed box-like structures and the vertical front and rear walls of the tubular member 33 are transversely extending plate members 34 spaced to define respective rectangular enclosures for bellows-like pressure pods 35 secured to horizontal platen ssemblies 36 presently to be described. In the typical embodiment described herein, four sets of enclosures are defined for each horizontal fixed frame portion and the bellows-like pod elements are arranged in pairs located respectively on opposite sides of the longitudinal tubular frame member 33 of each horizontal frame section, as shown in FIGS. 5 and 6. Each bellows-like pod member 35 is secured to and depends from a pair of spaced transversely extending angle bars 38,38 rigidly secured between the vertical walls of the central horizontal tubular frame member 33 and the longitudinally extending outer vertical plate members 26, as shown in FIGS. 5 and 6. Each platen member 36 is secured to and moved by the bottom walls of a pair of transversely aligned bellows-like pod members 35. As shown in FIGS. 2 and 6, the horizontal platen members 36 are generally rectangular in shape and are of hollow construction. The platen members are provided at their comers with upstanding vertical plunger elements 39 which slidably engage in depending vertical guide cylinders 40 rigidly secured to and depending from the horizontal

top plate members

24 or 29, so as to accurately guide the horizontal platen members 36 for vertical movement.

The pressure pods 35 are of conventional construction, and may be similar to Airstroke Actuators manufactured by Firestone Industrial Rubber Products Company, Noblesville, Indiana.

The platen members 36 are lowered and raised by the respective expansion and contraction of their associated pressure pod members 35. Each'set of pressure pod-members35,35', associated with a particular platen member 36,-is'connected by a respective conduit 41 to a supply conduit 42 (see FIG. 7), the conduits 41 extending through the central horizontal longitudinal hollow member 33. Conduit 42 may be communicatively connected to either a vacuum line 45 or a compressed air line 46 depending upon the condition of an associated main control valve 44 which is of the two-position type and which is connected between the pair of pods 35 and the

lines

45 and 46 in the manner diagrammatically illustrated in FIG. 7. Thus, the main control valve 44 associated with each pair of bellows-like pod elements 35 is normally biased to a position such as that diagrammatically illustrated in FIG. 7 wherein the conduit 42 is connected through the valve and a conduit 47 to the vacuum line 45. Valve 44 is of the pressureactuated type, and each valve 44 is controlled by 'a respective pilot valve 48 of the solenoid type. Thus, in the normally, deactivated, condition of main valve 44 the line 42 is connected to the vacuum line 47, as above mentioned. When the valve 44 is actuated the line 42 becomes connected to a conduit 49 which is in turn connected to the compressed air line 46. This occurs when the solenoid of the associated pilot valve 48 is energized, thereby connecting the conduit 50, shown in FIG. 7, to the pressure conduit 46. Thus, in a normal condition of the parts, the

bellows members

35,35 are connected to the vacuum line 45and are contracted, causing the platen member 36 to be elevated. When the solenoid of the associated pilot valve 45 becomes energized, compressed air is admitted to the associated main valve 44 through the line 50, and the supply line 42 for the

pods

35,35 becomes connected to the compressed air supply conduit 49 by the action of valve 44, causing the

pods

35,35 to expand and to exert downward force on the associated platen member 36, causing said platen to move downwardly through a mold box-compressing stroke.

From the above, it will be apparent that a pilot valve 48 is provided for each of the twenty platens 36 of the typical assembly illustrated in the drawingsand described herein. The diagram of FIG. 7. illustrates the manner in which the

pods members

35,35 of the extreme uppermsot left platen member are connected to the main compressed air. supply line 46 and vacuum line 45, and in this typical instance, the solenoid for the associated pilot valve 48 is identified as 81A. The pneu matically actuated components, shown in the dotted rectangle in FIG. 7 represent those required for eachv platen member 36, and it will understood that corresponding' assemblies are provided for each of the other nineteen platen members of the illustrated apparatus.

As shown in FIG. 7, vacuum is maintained in line 45 by a vacuum pump 52 driven by an electric motor M3. A vacuum sensing switch SW6, presently to be described, is connected to the vacuum line 45.

Elevator screws 53 are vertically joumaled at the respective corners of the frame structure thus far described. Thus, the lower ends of the screws are rotatably supported in bearing brackets 54 rigidly secured motor M1 of the reversible type. The motor M1 is suitto the lower portion of the plate members 23 and the upper portions of the screws are rotatably supported in sleeved bearing brackets 55 secured to the transverse top end plate 27. The top ends of the screws 53 have bevelled gears 56 secured thereto, said bevelled gears being meshingly engaged by bevelled gears 57 provided on the ends of the shaft 32. Mounted on the intermediate portion of shaft 32 is a relatively large sprocket wheel 53 which is drivingly coupled by a sprocket chain to a smaller sprocket wheel on the shaft of a drive ably mounted on horizontal top plate 29. Motor MI is operated in a conventional manner and the forward and reverse operation thereof occurs in response to en ergization respectively of coils MlF and MIR illustrated schematically in FIG. 8B.

It will be understood that a drive shaft 32 is provided at each side of the machine; namely, on the front side and on the rear side, and that each shaft 32 is coupled ina similar manner to the respective elevator screws 53,53 at its side of the machine. The rear driving shaft 32 is provided with a sprocket wheel 58 and is coupled by .a sprocket chain to a smaller'sprocket on the shaft of the motor M1 in the same manner as above de scribed for the front elevator screws 53. Thus, when the motor M1 is energized, the screws 53 rotate simultaneously in the same direction, either forward or reverse, to provide elevation or lowering of the elevator assembly presently to be described.

The elevator assembly is designated generally at 60 and comprises a generally rectangular framework having transversely extending end plate members 61 whose front ends are rigidly connected by a longitudinally extending vertical plate member 62. The transversely extending end plate members 61 are located outwardly adjacent the vertical frame bars 28,23 at each end of the main frame of the machine, and are provided with internally threaded vertical sleeve members 64 rigidly secured to the plate members 61 and threadedly engaged with the elevator screws 53. A longitudinally extending angle bar 65 is employed to rigidly connect the transversely extending vertical end plates 61 at the lower marginal portions of said transversely extending plates at the front portion of the elevator assembly. 60, and a longitudinally extending channel bar 66 is likewise employed to connect the lower portions of the plates 61 adjacent the stationary main frame of the machine, as shown in FIG. 3, to rigidify this portion of the elevator member. The rear portions of the transversely extending end plates 61 are rigidly connected by a pair of longitudinally extending spaced channel bars 69 and means for limiting rearward movement of mold boxes ejected rearwardly from the platen press assemblies. as shown in dotted view in FIG. 4. i

As shown in FIG. 3, alongitudinally extending channel bar 74 is secured vertically between the end plates 61 adjacent the vertical plane of the front wall plates 26 of the pod enclosures on the main chine.

As shown in FIG. 2, the adjacent transverse edges of elevator top plates 27 at the front portion of the elevator assembly 60 are spaced apart to define guide ways substantially centered with respect to the vertical rows of platen members 36. Rigidly secured in these guide ways are parallel pairs of transversely extending

guide rods

75,75, the front ends of the rods being secured to brackets 76 rigidly secured to the upper marginal portion of front plate 62, and the rearends of the guide rods 75 being secured to supporting blocks 77 which are in turn rigidly secured to the top flange of the longitudinally extending channel-shaped frame bar 74. Slidably mounted on the respective pairs of guide bars 75,75 are pusher carriage blocks 77 having horizontal flat bar members 78 rigidly secured to and projecting rightwardly therefrom, as viewed in FIG. 3. Rigidly secured on the rightward ends of the bar members 78, as viewed in FIG. 3, are clamping blocks 79 having horizontal slots in which are adjustably mounted horizontally extending pusher bars 80 which extend parallel to the guide rods 75 and which are provided at their rearward ends (right ends as viewed in FIG. 3) with mold box-engaging longitudinally extending vertical pusher plates 81, the bars 80 being adjustably clamped in the blocks 79 by the provision of manually operable clamping screw members 82 thread-edly engaged through the top walls of the slots in the blocks 79.

The carriage blocks 77 are provided with pairs of depending spaced bracket elemetns 83 which receive therebetween and are secured to the top runs of respective endless sprocket chains 84 which extend transversely and which are supported on respective

idler sprockets

85 and 86 secured on

longitudinal shafts

87 and 88 journaled between the end plates 61, the shaft 87 being located adjacent the front longtudinal wall plate 62 and the shaft 88 being located adjacentthe longitudinally extending channel bar 74, as is clearly shown in FIG. 3. A pusher motor M2 provided with a reducing gear assembly 90 is mounted on the longitudinally extending channel bar 66 and has an output sprocket 89 drivingly coupled by a sprocket chain 91 to a sprocket 92 mounted on the shaft 88, whereby the motor M2, which is of the reversible type, is drivingly coupled to the carriage blocks 77 of the respective above-described pusher assemblies.

As shown in FIG. 4, a longitudinally extending shaft 93 is journaled between the upper portions of the plates 61 and secured on shaft 93 are a plurality of rollers 94, shaft 93 being located rearwardly adjacent the vertical plane of the rear wall plates 26 of the platen pod enclosures. The rollers 94 are located so that their top peripheral surface portions are substantially coplaner with the top plane of the upstanding mold conveyor assemblies 68, as is shown in FIG. 4. Shaft 93 is drivingly coupled to shaft 88 by a sprocket chain 95 which is meshingly engaged respectively with a drive sprocket 96 secured on the end of shaft 88 and a driven sprocket 97 secured on the end of shaft 93. Thus, the rollers 94 are simultaneously rotated in a clockwise direction, as viewed in FIG. .4, as the pusher carriage blocks 77 move rightwardly, as viewed in FIG. 3. Therefore, as a mold box, shown at 98 is pushed rightwardly by a pusher pad 81, as viewed in FIG. 3, it engages a previously processed mold box restingon a horizontal supporting plate 24 and pushes said previously processed frame of the mamold box rightwardly as viewed in FIG. 3 and as viewed in FIG. 4, so that it is engaged by a roller element 94 and propelled further rightwardly onto the spherical ball conveyor elements 68, its rightward movement being limited by it engagement with the stop bar 73, above described.

As shown in FIG. 1, the platen members 36 are constrained to move vertically by the provision of vertical guide means comprising upstanding vertically projecting guide bars 99 rigidly secured to the mid-portions of their front edges, said guide bars 99 being slidably received between and being contained between cooperating pairs of inwardly flanged vertical guide rails 100,100 vertically secured to the outside surfaces of the longitudinally extending wall plates 26 of the pod enclosures. Cooperating guide bars 99 and pairs of guide rails 100 are provided both on the front side and the rear side of each pod enclosure so that the associated platen member 36 is positively contrained to move vertically. This assures that parallelism will be maintained between the platen members 36 and the cooperating subjacent fixed supporting plate members 24.

In a generalized mode of operation of the machine, the elevator member 60 is normally positioned at a level so that it is flush with a mold box-feeding conveyor leading from a station at which the molds are filled. A filled mold box from said station is manually rolled onto the elevator 60 from said station, being supported on the transfer ball assemblies 68 and is manually moved into alignment with a vertical row of platen press assemblies containing a platen press assembly which is ready to be refilled. As will be presently described, an illuminated indicator on a control panel 101 informs the operator of the correct location in which to place the mold box to be processed. The operator then actuates'a suitable control switch to bring the elevator member 60 to the proper level corresponding to the available platen press unit, after which the associated platen member 36 is elevated and the pusher mechanism is activated to push the new mold box into the platen press position and simultaneously cause the previously processed mold box to be ejected and moved to the rear portion of the elevator assembly in the manner above described; namely, by the action of a roller 94. The pusher member 77 is retracted and positive pressure is applied to the pod assembly containing the new mold box, whereby to apply molding pressure thereto, and the elevator member 60 is returned to its home position, flush with a receiving conveyor on which the previously processed mold box is moved, and at which the elevator is in the proper position to receive the next mold box to be processed from the feeder conveyor.

The above described general cycle of operation may be accomplished either by manual control of the electrical circuits associated with the respective operating motors, or by an automatic control circuit, presently to be described.

Thus, referring to FIGS. 8a and 8b, the apparatus is provided with a main supply transformer 102 having input terminals L1 and L2 which may be suitably connected to a source of energizing alternating current. The secondary winding 103 of transformer 102 has one terminal connected through series-connected normally closed protective motor overload switches XMI, XM2 and XM3 to a common supply wire 104. The remaining terminal of transformer secondary winding 103 is connected through a fuse 105 and a normally closed stop switch SW5 to the stationary contact 1106 of a two position selector switch SW4 having a pole ll)? which may be moved either to a first position bridging contacts 106 and d or a second position bridging contact 109 and Jill). The stationary contact 1% is connected to stationary contact Hit.

A wire llllll, associated with the various switches for providing manual operation of the elements of the machine, is connected to the stationary contact 1W9. When switch SW4 is placed in its manuaP position; namely, with the pole 107 in a dotted view position thereof shown in FlG; 8a, the wire 1111 is connected to the secondary 1030f transformer i102, and the various operating components may be independently controlled through respective individual energizing circuits connected to wires 1111 and 1104 through respective manually operable control switches. Thus, the forward and reverse coils MllF and MllR of the elevator motor Ml may be independently controlled by employing a conventional reversing switch for selectively connecting these coils between the wires 111i and lltld so as to provide operation of the elevator member 6d in a desired direction. Likewise, the forward and reverse actuating coils MZF aNd MZR of the feeder motor M2 may be selectively controlled by a manually operated reversing switch in the same manner; namely, by providing a means for selectively connecting these coils between the wires lllll and 104, as desired. This provides manual control of both the elevator motor M1 and the feeder motor M2. In the same manner operated selector switches may be provided on a controlpanel 112 for energizing the respective timers employed to control the energization of the solenoids of the respective press pilot valve 48 associated with each of the pairs of

pressure pods

35,35 of the respective platen press as semblies. Thus, manuallyoperated energizing switches may be employed to selectively energize the solenoids of the pilot valves 4b to provide a timed press cycle. The manually controlled energizing circuits are not illustrated herein, since it is believed that these circuits are in themselves quite conventional and would be well known to anyone skilled in the art. I

As will be presently described, the timers which are employed to control the duration of energization of the solenoids of the press pilot valves 48 are of a type which includes a signal lamp 128 which becomes energized simultaneously with the energization of the timer as it begins its timed period of operation. The timer MT employed in each platen press assembly is of a commercial type and may be similar to Model No. 125 manufactured by Eagle Signal Company, Inc., Baraboo, Wisconsin.

FIGS. ha and db, taken together, represent the typical circuit arrangement required to operate one of the platen press assemblies automatially, for example, the uppermost left end platen press assembly of the 2d unit machine shown in FIG. l. The control circuits for the other platen press assemblies are substantially identical to that illustrated in FIGS. 8a and 3b and are interconnected with the main components of the system in the same manner as illustrated in these figures. Thus, the uppermost left end press assembly in the machine of FIG. I is identified by the reference numeral 1A, and in the circuit description certain elements will be referred to this identifying symbol, while other elements in the circuit will be referred to corresponding identifying symbols relating to elements controlled by portions of the circuit components of other press assemblies of the machine so as to provide required interlocks. Thus, a relay R1 is provided, this relay being associated with the uppermost level of platen press assemblies. A corresponding relay R2 is associated with the next subjacent level, etc., the relay for the lowest level being identified by R3. in the over-all system, alphabetical designations are employed to distinguish between different vertical rows of platen press assemblies; for example, A, B, C andD, reading from left to right in FIG. 1, and numerical indicia are used to distinguish between different levels proceeding downwardly from the uppermost level. For example, FIG. ll illustrates a mold box 33 being pushed into the platen press assembly 41); namely, the fourth platen press assembly from the top at the right end of the machine, as viewed in FIG. 1.

. Certain portions of the circuit of FIGS. 8a and 8b are common to all the other platen press assembly circuits. For example, the vacuum switch SW6, connected in the manner shown in FIG. 8b will afiect the circuits of the other platen press assemblies in the same manner as it affects the circuit of the platen press assembly 1A. The same is true with respect to the relay shown at R6, and the elements thereabove, including the enable switch SW3, the automatic-manual selector switch SW4 and the stop switch SW5.

With the switch SW il in the full line position thereof shown in FIG. 8a; namely, with its pole 107' bridging the stationary contacts 106 and N8, it will be seen that the enable relay 7 R6 becomes energized when the enable switch SW3 is operated toits dotted view position, and relay R6 will be held energized by the closure of its holding contacts R6,. With all the elements in normal positions; namely, with no mold boxes in the platen press assemblies, this will illuminate all of the push button switches, which are of a type provided with illumination lamps 129, the lamps 1129 being connected in the manner illustrated in MG. 3a. Thus, the lamp 129 associated with switch SWllA has one terminal thereof connected to wire W4 and has its other terminal connected by a wire ll 13 to a stationary contact 3 of the associated timer MT. The contact 3 is connected by a wire lid to a wire 1115, which is in turn connected to a stationary contact 7 of timer MT, normally engaged by a pole llllb of the timer switch assembly, said pole having a terminal 6. Terminal 6 is connected by a wire 117 to a wire 118 which is connected to a stationary contact 1.19 of the push button switch SW TA. Contact 1119 is connected through the contact R6 of relay R6 to a wire 120 which is connected to one of the contacts 121 of switch SW3, which in turn is connected to stationary contact W8 of the selector switch SWd. Therefore, lamp 129 becomes energized with the closure of the relay contacts R6 and remains energized until timer switch pole lilo disengages from contact 7.

It will be understood that in the normal starting condition of the press, the elevator member 60 is in its intermediate position; namely, at a position aligned with the third or middle horizontal row of platen press assemblies. As above explained, in this position the elevator member 6% is flush with the conveyor leading from the mold box-filling station, and therefore can receive a filled mold box therefrom. Assuming that the mold box is to be processed in platen press assembly 1A, the operator moves the filled mold box leftward on the elevator member 6d until it is aligned with the first vertical row of platen press assemblies; namely, that containing the platen press assembly 1A. With the mold box in this position, the operator then actuates the illuminated push button switch SW1A. Switch SWlA is of the two pole type and has a first pole 122 bridgingly engageable with a pair of

stationary contacts

119 and 123, and a second pole 124 bridgingly engageable with a pair of

stationary contacts

125 and 126. When pole 122

bridges contacts

119 and 123, a platen relay RlA becomes energized, since the winding of this relay has one terminal thereof connected to wire 104 and the other terminal thereof connected by a wire 127 to contact 123. Relay R1A is held closed through a holding circuit including its contacts R1A RlA and R1A which connect wire 127 to switch contact 119. Relay contacts RlA are of the normally closed time opening type providing a time delay in opening after relay RIA becomes energized. The relay R1 for the first elevation is likewise energized by the actuation of switch SW1A, since the winding of this relay has one terminal thereof connected to supply wire 104 and the other terminal thereof connected by a wire 130 through normally closed timed-opening contacts R1, of this relay to the switch contact 126. As shown in FIG. 8a, the opposite stationary switch contact 125 is connected to the wire 118, which is in turn connected through contacts R6 to switch contact 108, as above described. Relay Rl-is held energized for a period of time since the contacts R1 are of the timed opening type.

Energization of the relay R1 causes its contacts R1 (FIG. 8b) to close, which energizes the forward-driving motor coil MlF of the elevator motor M1 through a circuit including normally closed reverse coil interlocked contacts M1 the normally closed contacts RM 1,, of a motor-starter relay RMl, a wire 131, a set of normally closed limit switch contacts 132, and the relay contacts R1 From FIG. 8b it will be seen that the motor driving coil MlF is connected in this branch circuit between the

power supply wires

104 and 118. The limit switch contacts 132 are normally closed and are part of a limit switch assembly LS1 having a second pair of contacts 133 which are normally open as shown in FIG. 8b. The limit switch LS1 is mounted on the frame of the machine in a position so that it becomes actuated by the elevator member 60 when the elevator reaches the uppermost level of platen press assemblies; namely, that containing the selected platen press assembly 1A.

As shown in FIG. 8b, the reverse motor driving coil MIR, for lowering the elevator assembly 60, has an en- -ergizing circuit connected between

wires

118 and 104 which includes normally closed interlocked switch contacts Mlp which open when the forward motor driving coil MlF becomes energized. This energizing circuit also includes in series connection normally closed contacts RMl of the starter relay RM], normally closed interlock relay contacts R R4 R2 and R1 and a normally closed limit switch LS located on the main frame of the machine in a position such that it is held open when the elevator member 60 is in its normal home position; namely, at the intermediate, or third, level of platen press assemblies.

The energization of the elevating coil MlF, by the circuit above described, causes the elevator member 60 to move upwardly, allowing limit switch LS4 to close, but the energizing circuit for reverse driving coil MIR remains open because contacts R1, of relay R1 are held open at this time.

When the elevator member 60 reaches its intended height, namely, the level of the selected platen press assembly 1A, it operates the limits which LS1, opening the contacts 132 and closing the contacts 133.

The opening of the contacts 132 de-energizes the forward motor driving coil MlF, causing the motor to stop and causing the elevator to stop at the intended level; namely, that corresponding to the platen press assembly 1A.

. The vacuum responsive switch SW6 has a first set of normally open contacts 134 which close responsive to a predeterminded degree of vacuum in the vacuum line 45. This degree of vacuum must be sufficient to cause the

pods

35,35 of the selected platen press assembly to contract and elevate their associated platen member 36 sufficiently to permit the insertion of a mold box therebeneath. The vacuum responsive switch SW6 has another set of contacts 135 connected in the energizing circuit of the vacuum pump motor M3, the contacts 135 closing when the vacuum falls below a limiting level, so that the motor M3 is energized sufficiently to maintain the required degree of vacuum in the line 45.

Thus, with the required vacuum in line 45, when limit switch LS1 is actuated, closing its contacts 133, a relay RFS becomes energized. As shown in FIG. 8b, the winding of the relay RFS is connected between supply wire 104 and wire 118 through the normally closed contacts RFl of a forward feeder control relay RFl, the normally closed contacts 136 of a limit switch LS2, the vacuum switch contacts 134, the contacts 133 of limit switch LS1, the relay contacts RIA, of relay RlA, the wire 115, timer contact 7, timer swith pole 116, timer terminal 6, and wire 117. This energizes the relay RFS. This relay has a set of slow closing contacts RFS connected between a wire 137 and one terminal of the forward driving coil M2F of the feeder motor M2. As shown in FIG. 8b, the wire 137 is the same as that connected to one terminal of relay RFS in the branch circuit above described. Thus, after the time period required to close contacts RPS, the forward driving motor coil MZF becomes energized in parallel with the winding of the relay RFS.

The elevator member 60 is provided with a limit switch LS3 which is normally engaged by the feeder mechanism, for example, the carriage member 77 so as to maintain the first set of its contacts 138 open and a second set of its contacts 139 closed. When the motor M2 becomes energized in the manner above described, the feeder mechanism is actuated so as to move the carria'ge member 77 and associated parts inwardly; namely, rightwardly as viewed in FIG. 3, which releases the limit switch LS3.

It will be noted that a relay RE has its winding connected between

wires

104 and 118 through the limit switch contacts 139. When limit switch contacts 139 open responsive to the inward movement of the feeder carriage assembly, relay RE becomes de-energized. Relay RE has a set of contacts RE,, and therefore these contacts close when relay RE becomes de-energized. It will be noted from FIG. 8a that the contacts RE are in shunt with the timed-opening contacts Rl in the holding circuit of the relay R1. Thus, relay R1 continues to be energized during this phase of operation.

The contacts 138 of limit switch LS close but do not have any effect at this point.

The feeder mechanism reaches the end of its stroke wherein the mold box 98 is pushed into the press space beneath the associated platen member 36. The elevator member is provided with the limit switch LS2 located so as to be operated by the carriage assembly as it reaches the end of its stroke. Limit switch LS2 has respective sets of contacts 140 and 136, as shown in FIG. 8b, the contacts 136 being normally closed and the contacts 141) being normally open. When the feeder mechanism reaches the end of its inward stroke, the contacts 136 open and the contacts 1410 close. The relay RFS becomes ole-energized, opening its contacts RF5,, thereby de-energizing the forward motor drive coil M2F. This causes the feeder to stop its operation at this point. Thus, the contacts RPS, are of the slow closing type, so that there is a short time delay after relay RFS becomes energized before the motor coil MZ becomes energized, but these contacts open immegiately responsive to the de-energization of relay RF The closure of the contacts 149 of limit switch LS2 energizes a relay RF2 whose winding is connected between wire IM and wire 118 through the limit switch contacts 140, as shown in FIG. 8b.

The timer operating coil, shown at 141 in FIG. @ahas one terminal thereof connected to supply wire 11M and the other terminal thereof connected to timer terminal 1, which is in turn connected through normally open contacts RF2, of relay RF2 and through contacts R1A of relay R1A to the switch stationary contact 119, and hence to supply wire 118. Hence, the closure of relay contacts RF2, causes the timer winding 141 to become energized and to initiate a timer cycle.

Since the contacts 138 of limit switch LS are closed when the feeder carriage member 77 moves inwardly, the energization of the relay RFZ at the end of the inward feeding stroke causes its contacts RF2 to close and to energize a relay R1 1 which is connected between

wire

101 and 118 through said relay contacts and the limit switch contacts 139. A pair of holding contacts RF1, of relay RF1 also close, these contacts being connected across the relay contacts RF2 as shown in FIG. 3b, thereby holding relay RFll energized. A short time thereafter, the timer contacts 6 and 3 are bridged by. the timer switch pole 116, causing the solenoid 81A of the associated press pilot valve to be energized, since this connects said solenoid, shown at 81A inFlG. 8a, between wire 104. and wire 117. Similarly, the timer contacts 9 and 10 are bridged by another pole 112 of the timer switch assembly, which establishes a holding circuit for the timer winding 141 through the closed timer contacts 11 and 12 which, as shown in FIG. 8a are at this time bridged by a switch pole 143 of the timer switch assembly. Thus, with pole 142 in engagement with contact 19, the holding circuit for the timer winding 1 11 will comprise wire 11M, a wire 114, the timer winding 141, the timer terminal 1, a wire 1 16 connected to the timer stationary switch contact 12,

pole M3, a wire 1147, switch contact 111, the pole 142, the timer terminal 9, and wire 117, which is connected to the other supply wire 11%. The energization of the solenoid of press pilot valve SlA causes the associated

pod elements

35,35 to become inflated, in the manner above described, and thereby causes the platen member 36 to move downwardly and exert pressure on the mold box. As will be apparent from FIG. 3b, the energization of the relay RF1 de-energizes the forward driving coil MZF of the feeder motor M2 by the opening of the relay contacts RFL. The relay RF1 has a set of slow closing contacts RF1, which are connected in series with the reverse driving coil M2R'in a circuit between wire 11% and limit switch contacts 133, so that after a short period of time subsequent to energization of relay R1 1, the reverse driving coil MZR ot the feeder motor M2 becomes energ'zed and starts the feeder carriage member '77 back toward its home" position. This releases limit switch LS2, causing contacts Mil to open and 13b to close, thereby de-energzing relay R1 2, but no other change takes place in the system at this point since the relay RE remains de-energized, its contacts Re, remaining closed and thereby maintaining relay R1 energized. Relay contacts RF2 open due to the deenergization of relay RFZ, but relay RF1 is held energized through its holding contacts RF1, and contacts 133 of limit switch LS3. The closure of limit switch contacts 136 does not efl'ect any change since at this point the contacts RlF1, of relay RFI remain open.

The feeder carriage member 77 eventually returns to its leftward, or starting, position and trips limit switch LS3, closing the contacts 139 and opening the contacts 133. The closure of the contacts 139 energizes relay RE whose winding is connected between wires 11141 and 113 through the limit switch contacts 139, as shown in FIG. 8b. This de-energizes the relay R1, since its holding circuit is opened by the opening of the contacts RE, of the relay RE, as shown in FIG. 8a. It will be seen from this figure that the holding circuit for the relay R1 comprises parallel-connected sets of relay contacts R1 and RE,, together with a set of relay contacts R1, of the relay R1. The relay contacts R1 shown in FIG. 8a are of the timed opening type, so that after the relay R1 becomes energized, the contacts R1 open after a short time period, so that the resultant holding circuit then consists of the contacts RE, and the contacts R1, in series. Thus, the opening of the relay contacts RE, opens this holding circuit, causing relay R1 to drop out when limit switchLS3 is tripped as above described.

The opening of the contacts 133 of limit switch LS3 tie-energizes the relay R1 1, causing its contacts RF1 to open and thereby de-energize the reverse driving coil MZR of the feeder motor M2. The feeder motor thus stops leaving the carriage member 77 in its normal starting position, as shown in full line view in FIG. 3.

The de-energization of the relay R1 at this point causes its'contacts R1 as shown in FlG. 8b to close. Since at this time the elevator member 69 is away from its normal position, the contacts of the limit switch LS4 are closed,; namely, in the dotted position thereof shown in FIG. 3b, so that the energizing circuit for the reverse driving coil M1R of the elevator motor becomes completed, through the closed interlock contacts Mllp, RM1 R5,, R4,, and R2,. Elevator 60 then begins to descend, releasing limit switch LS1, causing its contacts 133 to open and its contacts 132 to close. However, no other change in the system occurs at this point, since contacts R1,, of relay R1 are open. The opening of the limit switch contacts 133 likewise causes no further change in the system at this point, since the contacts RF5, of the relay RPS are likewise open. When elevator 61) reaches its normal position; namely, its intermediate position above described wherein it is at the third level of the assembly, it trips limit switch LS4, causing it to open and thereby tie-energizing the reverse driving coil M1R of the elevator motor M1, causing the elevator to stop in this position. The relay RlA has a timed-opening set of contacts 121A, which times out after a period of energization of relay RlA sufficiently long to allow the above described events, so that the relay RlA then drops out, allowing its other holding circuit contacts RIA, and RlA as shown in FIG. 8a, to open, and also allowing another set of contacts thereof R1A.,, connected between wire 115 and contacts 133 of limit switch LS1 to open.

After a preset time interval, timer contacts 11 and 12 open by the disengagement of pole 143 from contacts 12, causing the timer to be reset. Pole 116 separates from contact 8, thereby opening contacts 6-8, thus deenergizing the solenoid 81A of the associated press pilot valve, allowing its main valve 44 to return to its normal position, as shown in FIG. 7, wherein the

pods

35,35 are reconnected to the vacuum line 45. This releases the pressure on the mold box and elevates the associated platen member 36 therefrom. Shortly before this time, pole l 16 engages contact 7, bridging the contact 6 and 7 and energizing the signal lamp 129 associated with the corresponding push button switch SWlA. Thus, this switch which is located on the panel assembly 101, becomes illuminated shortly before the end of the above described cycle, indicating that the mold box press unit 1A is available to receive another mold box to be processed in the machine. I

As previously described, when a mold box is inserted by the action of the feeder assembly, above described, the previously processed mold box is pushed outwardly onto the rear portion of the elevator member being engaged by a roller member 94 in the manner above described, to move the mold box 98 onto the roller elements 68 and rearwardly into engagement with the stop strip 73. The ejected mold box may then be manually moved onwardly on the receiving conveyor for demolding and further processing.

As abovementioned, the illuminated switches on the control panel assembly 101 inform the operator as to the correct positions to place mold boxes to be processed on the elevator member 60. Thus, the illuminated switches represent the respective available molding spaces in the machine and the operator places a mold box to be processed in alignment with a vertical row of spaces corresponding to that of an illuminated switch on board 101, which will thereafter be operated to automatically insert the mold box into the indicated processing space. The timer may be so arranged as to illuminate the signal lamp 129 a short time prior to the preset press time required; for example, the amount of prior time allowed may be about two seconds more than the length of time required for the elevator to move the mold box to its intended insertion position. When the operator pushes the start button, such as the operating button of the switch SWlA, as above described, the above cyce of events takes place, the associated signal lamp 129 becoming de-energized when the platen timer coil 141 becomes energized, initiating the timer cycle. This occurs when pole 116 disengages from contact 7, disconnecting wire 114 from wire 117, as above described. As previously mentioned, each timer is provided with another signal lamp 128 connected in parallel with its operating coil 141, and becoming energizing simultaneously with the energization of said operating coil.

From the above description, it will be seen that when the machine is placed in the "automatic" mode of operation, by operating the switch SW4 to the position thereof shown in full line view in FIG. 8a, all movements are automatic except for the placement by the operator of the mold box in alignment with the vertical row of platen press assemblies containing the one in which the mold box is to be inserted. The operation of the elevator and feeder members is quite rapid, and in a typical embodiment of the invention, the maximum time that the elevator member 60 is away its home" position was about 15 seconds.

As will be readily understood, when the mold box is to placed at levels below the home" position of the elevator member 60; for example, at the fourth of fifth level from the top, the response of the motor M1 which drives the elevator must be reversed as compared with that described above in connection with the placement of a mold box in the platen press space 1A. Thus, a reversing relay RMl (see FIG. 8b) is provided which responds to the operation of any of the push buttons associated with the fourth or fifth levels. Thus, the winding of the relay RMl is connected in an energizing circuit which includes parallel-connecting contacts of relays in the control circuits for the fourth and fifth level platen press assemblies corresponding to the relay RlA shown in FIG. 8a. Thus, operation of a push button associated with the fourth or fifth horizontal row of platen assemblies energizes a relay similar to the relay RlA, and closure of one of its contacts completes the energizing circuit for the relay RM]. and energizes same. As shown in FIG. 8b, the driving coils MlF and MlR have normal energizing circuits respectively containing normally closed contacts RMI, and RM1 of the relay RMl. Thus, energization of the relay opens these normal energizing circuits. Reversing connections are provided for energizing the drive coils MlF and MIR through respective reversing branch connections indicated respectively at 162 and 163. The reversing branch 162 contains a set of normally open contacts RMl of the relay RM1 which close responsive to the energization of relay RMl and thereby allow energization of the reverse drive coil M1R from the conductor 131 in place of the forward drive coil MlF. Similarly, the energization of the relay RMl closes a set of normally closed contacts RM1 of relay RMl connected in the reversing branch connection 163, allowing energization of the forward drive coil M1F in place of the reverse drive coil MIR. Thus, energization of relay RM1 provides a reversal of the connections for operating the motor drive coils MlF and M1R, required for moving the elevator member 60 to the fourth and fifth levels instead of to the first and second levels of platen press assemblies.

It will also be noted from FIG. 8b that the energizing circuits for the driving coils MlF and MIR contain respective normally closed interlock switch contacts shown at M1,, and MI Contacts M1,, open responsive to the energization of the motor driving coil MIR thereby preventing energization of the motor drive MlF at this time. Similarly, the energization of the motor drive coil MIF opens the interlocked switch contacts M1,, preventing energization of motor drive coil MIR. These interlocking sets of switch contacts prevent simultaneous energization of both motor drive coils. Similarly, the interlocking contact R1,, R2,, R4,, and R5, are normally closed and are connected in the energizing circuit for the motor driving coil which is energized to return the elevator member 60 to its home position, along with the limit switch LS4. These interlocked switch contacts open responsive to the energization of the relays corresponding to the relay R1 associated with the platen press assemblies of the first, second, fourth, and fifth levels. As shown in FIG. ha, the relay R1 becomes energized responsive to the bridging of

contacts

125 and 126 by the pole 154 when the switch SWllA is operated. Thus, the interlocked contacts R1 R2,, R5 prevent any return movement of the elevator member 60 when any of the relays for the first, second, fourth and fifth levels is energized.

While the multiple molding press of the present invention has been above described specifically for handling mold boxes employed with foaming plastic materials, it is readily apparent that the press of the present invention can have application for other types of work pieces, such as various types of laminated glued wood objects including laminated table tops, cabinet walls, top panels, or the like. These parts may be carried on a board, or similar plate-like support into position in the press. The press system of the present invention is also applicable to other gluing operations where; for example, two or more flat panels are stacked, freshly glued, ready for pressing.

While a specific embodiment of an improved multiple molding press assembly has been disclosed in the foregoingdescription, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed onthe invention except as defined by the scope of the appended claims.

' WHAT IS CLAIMED IS:

l. A multiple molding press assembly comprising upstanding frame means, a plurality of vertically spaced fixed horizontal work piece support elements on said frame means, respective horizontal platen members mounted on said frame means over said support elements, means to'independently reciprocate said platen 2. The multiple molding press assembly of claim l,

and wherein the means to reciprocate said platen member comprises respective fluid pressure-operated driving members connected between the platen members and said frame means. r

3. The multiple molding press assembly of claim 2,

sources, and means for selectively connecting said positive and negative pressure fluid sources to said fluid pressure-operated driving members.

41. The multiple molding press assembly. of claim 3, and wherein said driving members comprise flexible bellows members connected between the platen members and upwardly adjacent portions of said frame means.

5. The multiple molding press assembly of claim 41, and means normally connecting the bellow members to said negative pressure fluid source, said means for selectively connecting the sources to the bellows mem- '55 and respective positive andnegative pressure fluid bers comprising reversing valve means interconnecting the bellows members with said pressure fluid sources.

6. The multiple molding press assembly of claim 5, and wherein said reversing valve means comprises respective main fluid pressure-operated valves connected between the fluid pressure sources and said bellows members and having ports normally connecting said negativefluid pressure source to said bellows members and other ports connecting the positive fluid pressure source to the bellows members responsive to operating fluid pressure applied to the main valves, and independently controlled pilot valve means operatively connected between the positive fluid pressure source and the main valves.

7. The multiple molding press assembly of claim 6, and wherein said pilot valve means comprise respective valves having operating solenoids, and means to selectively energize said solenoids.

8. The multiple molding press assembly of claim 7, and means to prevent energization of a selected solenoid unless the vertically movable work piece receiving member is at a level substantially registeringwith the corresponding work piece support element.

9. The multiple molding press assembly of claim ll, and transversely movable work piece-engageable feeder means on the front portion of the work piece receiving member. I

, 110. The multiple molding press assembly of claim 9, and means to actuate said feeder means responsive to the positioning of said work piece receiving member at a selected position of registry with a horizontal work piece support element.

11. The multiple molding press assembly of claim 10, and means to move each platen member downwardly to press position responsive to actuation of said feeder means through a feeding stroke substantially sufficient to move a work piece beneath the platen member.

12. The multiple molding press assembly of claim 1 l, and means to maintain downward press force on the platen member for a timed period and to thereafter release the platen member.

13. The multiple molding press assembly of claim 12, and wherein said means to move each platen member downwardly to press position comprises an expansible bellows member connected between the platen member and an upwardly adjacent portion of said frame means, and means to admit pressure fluid into said bellows member responsive to the actuation of said feeder means through said feeding stroke.

14. The multiple molding press assembly of claim 13, and means to return said feeder means on said work piece receiving member after said feeder means reaches the end of said feeding stroke.

15. The multiple molding press assembly of claim 14, and wherein said work piece receiving member has a normal home position, and means to return said work piece receiving member to said home position at the end of the retraction stroke of said feeder means.

116. The multiple molding press assembly of claim 15, and wherein said normal home position of said workpiece receiving member is substantially in registry with one of said horizontal work piece support elements.

117. The multiple molding press assembly of claim 16, andwherein at least three vertically spaced fixed horizontal work piece support elements are provided and said normal home.position is in registry with an intermediate work piece support element.

18. The multiple molding press assembly of claim 1, and wherein the means to move said work piece receiving member vertically on said frame means comprises vertical screw means on said frame means and threadedly engaged with said work piece receiving member, and means to rotate said vertical screw means.

19. The multiple molding press assembly of claim 18, and wherein said screwmeans is journaled on said frame means and said means to rotate said vertical screw means comprises a reversible electric motor and means drivingly coupling said electric motor to said vertical screw means.

20. The multiple molding press assembly of claim 1, and transversely movable workpiece-engageable feeder means on the front portion of the workpiece receiving member, and wherein said transversely movable feeder means comprises transverse guide rail means on said workpiece receiving member, a workpiece engaging abutment member slidably mounted on said rail means, and drive means connected to said abutment member.

21. The multiple molding press assembly of claim 20, and wherein said last-named drive means comprises a reversible electric motor mounted on said workpiece receiving member, and means drivingly connecting said last-named electric motor to said abutment member.

22. The multiple molding press assembly of claim 20, and horizontal drive roller means longitudinally journaled on said rear portion of said workpiece receiving member for drivingly engaging a workpiece ejected rearwardly from beneath a platen member, and means drivingly coupling said roller means to said abutment member for actuation simultaneously therewith.

23. The multiple molding press assembly of claim 1, and wherein the means to reciprocate said platen members comprises respective fluid pressure-operated driving members connected between the platen members and said frame means, respective positive and negative pressure fluid sources, means for selectively connecting said positive and negative pressure fluid sources to said fluid pressure-operated driving members, and means to maintain the pressure of said negative pressure fluid source between predetermined limits.

24. The multiple molding press assembly of claim 23, and wherein said negative pressure fluid source comprises a vacuum pump and a drive motor operatively connected to said pump, said last-named motor having an energizing circuit including a pressure-responsive switch connected so as to respond to the output pressure of said vacuum pump, said switch having auxiliary contacts, transversely movable workpiece-engageable feeder means on the front portion of the workpiece receiving member, and means to inhibit action of said feeder means unless said auxiliary contacts are closed.

25. The multiple molding press assembly of claim 1, and transversely movable workpiece-engageable feeder means on the front portion of the workpiece receiving member, means to actuate said feeder means responsive to the positioning of said workpiece receiving member at a selected position of registry with a horizontal workpiece support element, means to move each platen member downwardly to press position responsive to actuation of said feeder means through a feeding stroke substantially sufficient to move a workpiece beneath the platen member, means to maintain downward press force on the platen member for a timed pe riod and to thereafter release the platen member, indicator means, and means to energize said indicator means a short time prior to the end of said timed period, whereby said workpiece receiving member may be started toward said selected position of registry with the horizontal workpiece support element.

26. A multiple molding press assembly comprising a support, a plurality of vertically spaced independently operable press units on said support, means to selectively operate said press units, a workpiece elevator adjacent said support adapted to receive a workpiece for pressure processing, means to selectively move said elevator vertically into registry with said press units, and means on the elevator to move a workpiece horizontally into a press unit when it is in registry with said press unit.

Claims

1. A multiple molding press assembly comprising upstanding frame means, a plurality of vertically spaced fixed horizontal work piece support elements on said frame means, respective horizontal platen members mounted on said frame means over said support elements, means to independently reciprocate said platen members, a horizontal work piece receiving member engaged on said frame means and being vertically movable thereon, said work piece receiving member having a horizontal front portion registrable with a selected horizontal work piece support element for feeding a work piece thereto for pressure processing and a horizontal rear portion simultaneously registering with the work piece support element for receiving a processed work piece therefrom, and means to selectively move the work piece receiving member vertically on said frame means to positions of registry with said horizontal work piece support elements.

2. The multiple molding press assembly of claim 1, and wherein the means to reciprocate said platen member comprises respective fluid pressure-operated driving members connected between the platen members and said frame means.

3. The multiple molding press assembly of claim 2, and respective positive and negative pressure fluid sources, and means for selectively connecting said positive and negative pressure fluid sources to said fluid pressure-operated driving members.

4. The multiple molding press assembly of claim 3, and wherein said driving members comprise flexible bellows members connected between the platen members and upwardly adjacent portions of said frame means.

5. The multiple molding press assembly of claim 4, and means normally connecting the bellow members to said negative pressure fluid source, said means for selectively connecting the sources to the bellows members comprising reversing valve means interconnecting the bellows members with said pressure fluid sources.

6. The multiple molding press assembly of claim 5, and wherein said reversing valve means comprises respective main fluid pressure-operated valves connected between the fluid pressure sources and said bellows members and having ports normally connecting said negative fluid pressure source to said bellows members and other ports connecting the positive fluid pressure source to the bellows members responsive to operating fluid pressure applied to the main valves, and independently controlled pilot valve means operatively connected between the positive fluid pressure source and the main valves.

8. The multiple molding press assembly of claim 7, and means to prevent energization of a selected solenoid unless the vertically movable work piece receiving member is at a level substantially registering with the corresponding work piece support element.

9. The multiple molding press assembly of claim 1, and transversely movable work piece-engageable feeder means on the front portion of the worK piece receiving member.

10. The multiple molding press assembly of claim 9, and means to actuate said feeder means responsive to the positioning of said work piece receiving member at a selected position of registry with a horizontal work piece support element.

12. The multiple molding press assembly of claim 11, and means to maintain downward press force on the platen member for a timed period and to thereafter release the platen member.

15. The multiple molding press assembly of claim 14, and wherein said work piece receiving member has a normal ''''home'''' position, and means to return said work piece receiving member to said ''''home'''' position at the end of the retraction stroke of said feeder means.

16. The multiple molding press assembly of claim 15, and wherein said normal ''''home'''' position of said work piece receiving member is substantially in registry with one of said horizontal work piece support elements.

17. The multiple molding press assembly of claim 16, and wherein at least three vertically spaced fixed horizontal work piece support elements are provided and said normal ''''home'''' position is in registry with an intermediate work piece support element.

19. The multiple molding press assembly of claim 18, and wherein said screw means is journaled on said frame means and said means to rotate said vertical screw means comprises a reversible electric motor and means drivingly coupling said electric motor to said vertical screw means.

25. The multiple molding press assembly of claim 1, and transversely movable workpiece-engageable feeder means on the front portion of the workpiece receiving member, means to actuate said feeder means responsive to the positioning of said workpiece receiving member at a selected position of registry with a horizontal workpiece support element, means to move each platen member downwardly to press position responsive to actuation of said feeder means through a feeding stroke substantially sufficient to move a workpiece beneath the platen member, means to maintain downward press force on the platen member for a timed period and to thereafter release the platen member, indicator means, and means to energize said indicator means a short time prior to the end of said timed period, whereby said workpiece receiving member may be started toward said selected position of registry with the horizontal workpiece support element.