USRE21906E - Plastic extrusion molding press - Google Patents

Description

Sept. 23., 1941 v. s. sHAw PLASTIC EXTRUSION lMOLDING PRESS Original Filed May 15, 1936 l2 Sheets-Sheet 2 v/cToR s. SHAW,

Sept. 23, 1941. v. s. sHAw PLASTIC EXTRUSION MOLDING PRESS 12 sheets-sheet 5 Original Filed May l5, 1936 Traum VICTOR S. 5 HHVV,

Sept. 23, 1941.

v. s. sHAw PLASTIC EXTRUSION MOLDING PRESS Original Filed May 15, 19,36 12 Sheets-Sheet 4 V. S. SHAW Sept. 23, 1941.

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Sept. 23, 1941. v. s. SHAW PLASTIC EXTRUSION MOLDTNG PRESS i936 12 Sheets-sheet 6 Original Filed May l5,

VICTORSHHW,

Sept. 23, 1941. v s. SHAW PLASTIC EXTRUSION MOLDING PRESS Original Filed May 15, 1956 12 Sheets-Sheet 7 Imm )y wc-roR SSA-mvv, Y

" sept. 23, 1941.

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PLASTIC EXTRUSVION MOLDING PRESS Original Fled May l5, 1956 l2 Sheets-Sheet 8 134 1 y f'l (1.8. F 161.15. 203

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PLASTIC EXTRUSION MOLDING PRESS Original Filed May l5', 1936 l2 Sheets-Sheet 9 F l Gr.10.

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PLASTIC EXTRUSION MOLDING PRESS Original Filed May l5, 1936 12 Sheets-Sheet 10 wcToR s. SHA vv,

M45@ www Sept. 23, 1941. y. s. sHvy Re. 21,906

PLASTIC EXTRUSION MOLDING PRESS Original Filed May l5, 1956 l2 Sheets-Sheet 11 sept. z3, 1941. v. s. SHAW Re. 21,906

PLASTIC EXTRUSION MOLDING PRESS Original Filed May l5, 1936 l2 Sheets-'Sheet l2 VCTOR S.SHAVV,

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iriFigilresIulldZ W V UNITED STATE PRICE 'ms'rlo Ex'raUsroN nonnina russ victor s. shaw, cai-ammi. ohio. ma 'rue Hydraulic Press Corporation. Inc., Wilmington, Del., a corporation ci Delaware icl. is-soi 1s claims.

This invention relates to injection or extrusion presses, and especially toA extrusion presses foi-molding thermoplastic materials like cellulose acetate, which can be re-softened and remolded by heat after cooling. as contrasted with materials like phenol resins which acquire a permanent set upon cooling.

One object of this invention is to provide an extrusion press having die members movable into engagement with an injector, and 'a-cli'ilrging and feeding arrangement for supplying measured quantities of materials to the press.

Another object is to provide a hydraulic circuit including such a press "and charging and feeding. arrangement, in combination with pumps for operating the hydraulic plunger-s, ywhich move the dies and injector into lengagement with /on'e another, and which also operate the charging and feeding mechanism.v

Another object is to provide such a press wherein the charging arrangement is operatively connected to thev feeding arrangement so that the former distributes measured charges to the ,latter in proportion to the quantity required by the latter. L-

Another object is to provide a charging and feeding arrangement having means for heating the thermoplastic materials during the charging and feeding operations, together with means for varying the temperatures applied to diiferent a certain part of the machine so as to lower the temperature of the portion which is by-passed.

Another object is to provide a hydraulic ex- -trusion press having independent sources of supplying pressure fluid to the die clamping cylinders and to the injection or extrusion cylinders so that the clamping pressure may he maintained at a dierent pressure level from the injection or Yextrusion pressure or be kept'independent thereof. y Y

In the drawings: i Figure 1 is a front elevation of the injection y or extrusion molding press of this invention.

Figure 2 is a view of the press shown in Figure 1, with the upper portion in vertical section through the axis of the clamping plunger, and

close the mechanism therein. Figure 3 is a top plan view oi' the Vpress shown with the front of the machine removed to dis- Figure iisya-'ieft-hand end elevation oi-the press..

Figure 5 is a right-hand end elevationv of the press. v

Figure 6 is an enlarged view of a portion of vFigure 5, with portions of thecasing removed to yshow the interior of Figure 2.

Figure '1 Vis `a central vertical section through ,the charging. heating and feeding arrangement mechanism. on the line 8 8 0f the Press.

portions of the press, although the heat is supo Figure 8 is a detail view of the mechanism interconnecting and synchronizing the injecting mechanism with the charging mechanism.

Figure 9 is a view 'ol the mechanism shown in Figure 8, but partly in section, in a.k plane at right angles to the view shown in Figure V8.

Figure 10 is an enlarged sectional view oi'. the meciganism shown at the left-hand side of Fig- Figure 11 is a diagrammatic sectional view of the press and its hydraulic circuit, with the various plungers in a retracted position. Figure 12 is a view 'similar to Figure l1, but with the die members moved into engagement with the injector, and with the injection operation about to take place. f

Figure 13 is a view` similar to Figures 11 and 12, but showing the positions of the parts and control leversr after the injection operation has taken place.

Figure 14 is a plan view of the extreme lefthand portion oi' Figure 7, showing the exterior appearance of the injecting and charging dev ces. k Figure 15 is'an elevational view of the supporting structure for themechanism shown in Figure 8.

General arrangement and hydraulic circuit Referring to the drawings in detail, Figures 1 and 2 show the' press ,of this invention as consisting ofa base. generally' designated ID, forming .a `tramel for supporting the various portions of the press. and valso inclosinga iluid tank I l for containing the operating fluid, such as oil, by which the various hydraulic members are actuated. Mounted upon the tank Il are hydraulic pumps l2 and ll, operated by a motor Il. The hydraulic pump l2 is of a conventional type, and

- is iitted with a pressure and volume control opwith the lowerportionshown in frontelevation,

Verated by the hand wheel II.

The latter acts upon the variable stroke mechanism in the pump I2 in such a manner as to cause a variable output of pressure fluid at working pressures, this output decreasing to zero at a predetermined maximum or peak pressure. .Such servomotor control arrangementsior hydraulic pumps are known to those skilled inthe art, and the details thereof form no'part of the present invention. t,

. tively, (Figure 2).

The hydraulic pump I3, on the other hand. is

tted with a pressure control operated by the hand wheel I6. This control acts upon the variable stroke mechanism of the pump llgin such the line 28, running to the injection control valve 2|. The branch line 22 continues onward from the pressure line 28, and distributes pressure fluid through the` check valve 23 and the line 22a to the pistons supporting one of the diemembers.-

as hereinafter explained. y,

' From the ports 24 and 25 of the injection control valve 2I the lines 25 and 21 run, respectively. to the opposite sides of the injection piston of the press, as' hereinafter explained. From the end pox- ts 28 and 29 the line 38 discharges into the fluid `tank II. The injection control valve 2| contains a valve member 3|, having valve heads 32 and 33, these being shifted bodily by means of the crank arm 34 operated by the injection control valve hand lever 35. As the vhand lever 35 is moved to and fro the valve heads 32 and 33 are moved Iupwardly or downwardly within the valve 2| so as to distribute fluid either to the line 26 `or to the line 21, as desired.

The hydraulic pump I3 receives uid from the tank II by way of the suction line 48, and discharges pressure fluid through the line 4"| leading to the clamping control valve 42 (Figures 2 and ll). The line 4| is likewise connected to the branch line 22a between the check valve 23 and the press. The check valve 23 prevents the return flowv of fluid toward the pump I2' when the pump I3 is operating, but when the pump I2 is in a `non-delivery position. From the ports 43 and 44 of the clamping control valve 42 the lines 45 and 45 lead. respectively, to the opposite sides of the clamping plunger of the extrusion press, as hereinafter explained. From theA line 45 the branch line 41 carries iluid to one side of thecharging plunger of the press, the opposite side of which is connected by the branch line 48 valve hand leverA 53. The hand lever 53 may be moved in one direction or the other to distribute duid from the line 48 alternately to the line 45 or 45, as desired. From the end ports 54 and 55 the return line 56 runs tothe tank II.

Extrusion molding press construction I' The extrusion molding press parts are mounted upon the base I8 (Figures 1 and 2), and are ar- This lcontrol tim ends the nuts 55 (Figure 11) threaded upon of the strain rods 54.

The clamping cylinder assembly consists of the cylinder bore I8, having the clamping piston 61 with the piston head 88 reciprocable therein. At one end of the cylinder bore 88 the port 88 is connected to the line 45 leading to the clampingcontrol valve 42. On the opposite vside of the piston head 53 is situated the port 18, connected to the line 48, likewise leading to the clamping f control valve 42. The packing 1I, compressed by ranged upon the top member 58 thereof. I'he clamping cylinder assembly 8| is mounted upon the left-hand side of the base top member 58,

the injecting cylinder assembly 52 isH mounted upon the right-hand end thereof, and the cushioning plunger assembly 88 is arranged between the assemblies 5| and 52, these being interconnected by the strain rods 84 secured thereto by the gland 12 through the agency of the cap screws 13, prevents leakage from around the clamping piston 515 The oppositeendk of the clamping piston 81 from the clamping piston head 58 has a reduced diameter portion 1t, upon which is mounted the die head 15 having the bore 18 arranged to receivethe reduced diameter portion 14." The ,outer ends of the die head 15 are prolvided with bores 11 containing bushings 18 surrounding and engaging the strain rods 84 (Figure ll) so as to provide a sliding engagement.

The die head 151s also provided with drilled portions 18 adapted to receive the bolts 88. for securing the die member 8| thereto. e The die member 8|, in turn, is provided with a lateral bore 82 arranged to receive a knock-out rod 83, the central portion of which is 'provided with a knockout pin 84 mounted in the drilled portion 85 of the die member 8|. The outer ends of the knock-out rod 83 are adaptedtoengage the ends of the threaded stops 35, these being mounted in the threaded bores 81 of the clamping cylinder' assembly 5|, and locked in position by means ,of

the locknuts 88 (Figure 11). The purpose of and the injector plunger 92 mounted upon the 4 other end (Figure 11). The cylinder bore 88 is provided with ports 83 and 84 at its opposite ends, respectively connected by the lines 28 and 21 to the injection control valve 2|. 'I'he packing 85, compressed by the gland 88, prevents escape of uid around the piston rod 88. Mounted upon the strain rods 84 and held in position between the enlargements 81 thereof and the spacing bushings 88 engaging the injecting cylinder assembly 52, is the cross-piece 88. This cross-piece, contains the cushioning cylinder bores |88, having the ports |8| connected by the lines 22a and 22 to the control valves 2| and 42, respectively. i

Mounted to reciprocate in the cylinder bores |88 are the piston heads |82 connected to the piston rods |83, the oppositeends of which are secured, as at |84, to the crosshead |85. The leakage of fluid around the piston rods |88 is prevented by means of the packings |88, arranged to be compressed by the glands |81. 'I'he crosshead |85 is provided with bores |88 con-A taining bushings |88 adapted to provide ending engagement with the strain rods 54, the latter having annular enlargements I8 serving as stops ilk) limit the forward movement oi the crosshead 85. `Mounted upon the crosshead |85 and secured thereto, as by theybolts ||I passing through theI holes ||2, is the die member III, cooperating with the previously-mentioned die member 8l.

#injector cylinder |20, within the boro |2| of which the injector plunger operates. The injector cylinder |20 is provided with a nozzle or nose portion |22, the tip of whichis adapted to o 3 thegear portion |51 and having mounted thereon the disc |50, carrying the stub shaft |50 upon which is mounted the ratchet pawl |00. The

fit snugly within the mouth ||1 of the passageway ||0 in the die member I2 when the latter is moved into engagement therewith, as hereinafter described;

The injector `cylinder is surrounded by a casing |22, providing a chamber for the circulation o! 'heating nuid for maintaining the molding material in a plastic condition,`as hereinafter explained. Projecting laterally from the iniector cylinder |20 is a charging cylinder |24, similarly surrounded by a casing for providing a chamber for the circulation of heating iluid therebetween. The charging cylinder |24 is provided with` a bore |20, within which the charglng plunger |21v is arrangedto reciprocate. On the opposite end of the charging plunger |21 is mounted the piston head |20, arranged to reciprocate wlthin the cylinder |20.. The opposite ends of thek cylinder |20 are provided with ports |20 and |2|, connected respectively to the lines 41 and 40,'previous1y described (Figure 11).

,Material-'niasurina and charging arrangement The material-measuring and charging devices .latter is arranged to engage the ratchet wheel IGI, which is secured by the key |02 to the shaft |41. Supported by the guide rollers |52 and arranged to engage the teeth ofthe gear portion |51, is a rack |00 (Figure 8), one end oi which is pivotally mounted/upon the pin |04 secured to the split collar |00. The latteris clamped to the arm `|00 by meansof the bolt |01. The inner end of the arm |00 is secured within the bore |00 in the crank armv |00 mounted upon the end of the shaft |10, and held in position by the nut |1| upon the threaded portion |12 thereof (Figures 8 and 9). The shaft |10 is supported in antifriction bearings |12, |14 and |15. The bearings |12 are mounted in a bracket |10 secured to the bracket |22. The anti-friction bearings |14'and |15, however, are mounted in a bracket |11, the lower portion of which rests upon the top member 00 of the main base I0 ofthe press.

are mounted upon a hollow` base |22, extending rearwardly approximately at right angles to the main `portion of the press (Figure 7)?. The cylinder |29, containing the piston headr |20 for operating the charging plunger |21, is supported by the bracket |22 mounted upon the top por- `tion |34 of the base |22. The charging cylinder bore |20 is aligned with a bore |25 (Figure '1), having an `aperture |20 in one side thereof. Above this aperture |30 is arranged a funnel member |21, adapted to direct materials through the aperture |20 into the bores |25 and |20.

The cylinder |20 is provided with a projection |30, this projection on the upper Vside of the cylinder |20 being adapted to support the chargemcasuring assembly. generally designated |20. The latter consists of a casing |40, having a conicai` upwardly extending portion |4| and a horizontal cylindrical bore |42 connected therewith by the vertical passageway |42. The conical portion |4| is provided with an interior conical surface |44 adapted to receive the conical lower portion of a hopper |45. The outer end of the bore |42y is connected to the funnel |21 so as to discharge into this funnel. Arranged to rotate within the bore |42 is a material-moving screw conveyor |40, mountedV upon the shaft |41 (F18- ures 9 and 10), the latter being journalled in tho anti-iriction bearings and |42, the latter being supported by the bracket extending rearwardly from the casing |40. Surrounding' the shaft |41 is a downwardly depending bracket 15|, .arranged to support the guide rollers |52 secured thereto, as 'by kthe cap screws |52 (Figures Band l0). The outer end of the shaft |41 terminates in a threaded portion |54 having the y thereon isy the sleeve |50, containing the teeth of Mounted upon the oppomte end of the shaft |10 from the crank arm |00 is a bifurcated arm |10 (Figure 9),- the outer ends of which are pivotally connected, as at |00, to links |19 (Figure 2). The opposite ends of the links |10 are pivotally connectedfas at"|0|, to a collar |02 mounted upon the piston rod 00. Consequently,

the reciprocation of the piston rod 00 and the injector plunger 02 will cause the bifurcated arm |10 to rotate the shaft |10, and move the varm |00 and the rack |02 to and fro by amounts directly proportional to the motion ofthe piston rod 00. As the rack |52 moves to the left (Figure 8') it will rotate the gear |51, and with it the disc |50, but the pawl |00 will slip loosely over the ratchet wheel |0| without engagement therebetween. Consequently, no rotation is imparted to the shaft |41 during the return motion of the injector plunger 02 and its position rod 00. During the injection stroke thereof, however, the

' gear |51and disc |50 will be rotated in the `opposite direction by the motion of the rack |02 to the right (Figure 8), whereupon the pawl |00 (Figure 10) will operatively engage the ratchet wheelv |0| and rotate the shaft |41.v The rotation of the shaft |41 and ,screw conveyor |40 will cause material placed in the hopper |45 to move to` the right (Figure 9), and be expelled into the funnel |21 andA thence through the aperture |20, intothe charging cylinder bores |35 and |20. The charging then takes place by the 4action o! the charging plunger |21 as impelled by the piston head |20, in a manner subsequently o to be described.

Heating arrangement .for maintaining materials in plastic condition f The molding material is maintained in a plastic, condition by the circulation of heated oil aroundconnected by the lines |05 and |00 (Figure 7) to o the indicating thermostat |01 (Figure i). The oil is circulated from the reservoir |02, throughout the various chambers, by means of a pump |00 driven by thev motor |00. The fluid is drawn from the reservoir |02, through the passageway |00 and the line |0I, 4into the pump |00, from which it is expelled through the line |02, into the chamber between the injector cylinder |20-and its surrounding casing |22 (Figures '1 and 1l).

From this chamber the oll ows through the pipe |93 and valve |94, into the chamber -between the charging cylinder |24 and its surrounding casing The oil then flows from the opposite end of the chamber, through the lines |95 and |96 into thel reservoir |63. The line |93 is connected to the line |96 by the by-pass line |91, containing the by-pass valve |98.

The oil in the 'reservoir |83K is heated by th heating unit |84 in response to the control of the thermostat |81. 'I'he heated oil. in passing through the passageway |90 on its way to the pump |88, surrounds the bulb |99,which is connected by the conduit 290 to the thermostat |81 so that the thermostat responds to the temperature of the oil surrounding the bulb |99 and im-' parts its control to the electrical heating unit |84 through the lines |85 and |66 leading thereto. The heated oil reaches the reservoir |83 from an ante chamber 20|, access to which is obtained through the filling connection 202 (Figure '1).

'I'he indicating thermostat |81 is mounted in a convenient location 'upon the front of Ithe press, as shown in Figure l. Also mounted in similar locations are the pressure gauges 203 and 204, arranged to indicate the pressure existing in the injecting and clamping circuits, respectively. The hand wheels I and I6 for controlling the pumps I2 and I3 and the hand levers 35 and 53 also project from the front apron ofthe press base, where they may be conveniently manipulated by the operator. t

Operation Before operating the press the various plungers are placed in retracted positions by shifting the control valve hand levers 35 and 53 away from one another, as shown in Figure 1l. The pumps I2 and I3 lare then started by starting the motor I4, and the heating fluid pump' |88 is operated by starting the motor |89. 42 in the positions shown in Figure 11, pressure iluid ilows from the pump I2, through the line 20, into the bore of the valve 2|, thence through the port 25, the line 21 and the port 94, into the space to the left of the piston head 9| within the injection cylinder bore 69, forcing the piston head 9| to the right and retracting the injector plunger 92. At the same time fluid ilows from the line 20, through the branch line 22, the check valve 23, the line 22a. and the ports 0|, into the cushioning cylinders |00, where this iluid acts against the piston heads |02 to force the crosshead 63 and die member ||3 to the left.

Meanwhile, the iluid expelled from the opposite end oi' the injection piston cylinder 89 returns With the valves 2| and to the tank by way oi the port 93, the line 26,

the valve ports 24 and 28 and the line 30. During this time the pump |3 discharges pressure fluid through the line 4|, into the clamping control valve 42, thence through the port 44 and the line 46, into the space to the right of the clamping piston head 68, forcing the piston head to the left and with it they die member 8|. The pressure iluid also continues from the line 46, through the line- 48 and the port |3I, into the cylinder |29, where it acts against the piston |28 to move the charging plunger |21 into its retracted posiltion. The huid expelled `from the opposite sides of the piston heads |28 and 68 passes through Jeewr, the handy lever s: 1s moved to the right into the position shown in Figure l2. In this position the pressure iiuid flows-from the control valve 42, through the line 45, into the space to the left of the clamping piston head 68, forcing the latter inwardly until the die member 8| en gages the die member I I3. When this occurs the die member ||3 is forced `rearwardly until its mouth ||1 comes into engagement with the nose |22 of the injector. The impact is cushioned by the gradual yielding of the cushioning piston heads |02 in the iace of the superior thrustog the clamping plunger 61. y M ggg While this is occurring pressure fluidi passes" from the line 45, along the line 41 and through the port |30, into the cylinder |29 (Figure 1l), where it acts against the piston head |28, forcing it inwardly and directing a charge of the molding material into the injector cylinder |20. The parts have now arrived in the positions shown in'Figure 12, with the two die members 8| and I I3 in engagement with one another and with the injector. To cause the injector plunger 92 to force the plastic material into the space between the molds, the hand lever 35 is now moved to the left until it occupies the position shown in Figure 13. AUnder thes'econditions pressure iluld now passes 'from the injector control valve 2|, through the line 26 and the port 93, into the space to the right of the injector piston head 9|, causing the `piston head 9|, the piston rod 90 and the injector plunger 92 to move to therleft, forcing a charge of the plastic material through the passageway ||6 into the recesses ||4 and ||5 ln the die members. Meanwhile, the material has been maintained in a plastic condition by reason of the circulation of the heated oil from the reservoir |83 through the lines previously described, and through the chambers surrounding :1;: charging cylinder |24 and injector cylinder When the molding operation is completed the hand levers 35 and 53 are moved away from one anotherinto the position shown in Figure l1. whereupon the various plungers are retracted, in the manner previously described. and returned to their original positions. As the die member 8| nears its retracted position the ends of the knockout rod B3 engage the ends of the threaded stopv members 85, bringing the rod to a halt, while the die -member 8| continues its motion to the left. (Figure 11.) This causes the knock out pin 84 to push the molded article out of the recesses 19 of the die vmember 8|, expelling the article and causing it tovdrop into the chute 20| (Figure 3), whence it emerges through the mouth 206 thereof (Figure 1) and falls into any suitable container.

When the advance of the injector piston rod occurs it moves the collar |82 forwardly and causes theracl: |63 to bring about a rotation of the screw conveyor |46, in the manner previously described in connection with the construction thereof. lA measured charge of the plastic Amaterial falls "through the funnel |31 and the aperture |36, into the bore |35,l whence it is im- ,pelled intor the bore |26 upon the subsequent Upon the return or f stroke of the plunger |21. retraction stroke of the injection piston rod 90. however, the rack |63 does not rotate the screw conveyor |46, due to the slippage oi' the pawl |60 over the ratchet wheel |6|. l

The thermostat |81 controls the electrical heating unit |84 to maintain the oil within the reservoir |83 at a substantially constant temperature verse the clamping plunger in order to close.

' In the` I have provided separate high. pressure pumps,

inresponse to the temperature of the oil impinging upon thebulbv III of the thermostat (Figure '1) If the by-pass valve vIII is completely closed the heated oil' will pass through the various chambersk and make a complete circuit. maintaining these chambers at substantially the same Y lmperamre. rf. however. it n desired to main- :a diiference"in temperature between-the l tain chamber surrounding the charging cylinder and the injection cylinder, the bypass valve ill is partially opened so that a por' tion of thenuid news `through the by-pass 'line Ill back to the reservoir Ill without.:passing through the'chamber surrounding the'charging cylinder |24. The by-pass valve |98 may be manipulated untii.the desired temperature difc ifereutial is obtained between the .various chamv Hbenal m Hitherto in injection or extrusion presses a single high pressure pump has been ,employedA to peri'ornithe functions both of clamping and 'of predetermined charge of material. and m nism automatically responsive to the motion of the material injecting element of said machine for rotating said screw conveyor to measure out and feed a predetermined charge oi' material to said charging chamber.

2,- A measuring and charging device for supplying material to a machine with a material injecting elementl andcomprising a charging chamber, a charging member therein, a measuring casing. a screw conveyor member therein adapted when rotated to measure out and feed a predetermined charge of material, a gear on said conveyor, a rack engaging said gear, and

mechanism automatically responsive to the motion-of. .the material injecting element of said machine for moving said rack to operate said .conveyor to measure out and feed a predetermined chargeof material to said charging chamber. 1

; '3. A measuring and charging device for supextrusion or injection'l assisted in some instances,v l

by a .flash pressure device orA by' check valves to trap the high pressure oil in the clamping cylinder whilethe high pressure pump actuated theV extrusion or injection plunger. Where a second pump was employed it was merely a large volume, low pressure pump, serving solely to rapidly trav,-

dies. V f 4 present invention it will be seen that each with its own automatic pressure control to supply pressure iluid'separately to the'cla'rnping plungers and extrusion or injection plunger. In

plying material to a machine withsl material linjecting' element and comprising a charging chamberi a charging member therein, a measuring casing, a screw conveyor member therein `adapted' when rotated to measure out and feed "a predetermined charge of material, a gear on said conveyor, a rack engaging said gear. mechanism automatically `responsive to the motion ofthe material injecting element of said machinefor 'moving said rack to operate said conveyor to measure out and feed a predetermined "charge ,of material to said charging chamber,

this manner it is possible to run the extrusion or injection pressure .at a lower level than the clamping pressure, and such a feature has' been found valuable in the practical operation of such presses. In this connection, it is apparent that and ratchet means disposed between said rack and said'- conveyor and adapted to operate said conveyor byfthe motion in one direction only of the die area, which the press will handle is dil Areetly proportional to the clamping pressure and inversely proportional to the extrusion pressure. yIt is therefore sometimes desirable to run the clamping pressure up tol the maximum and keep '4 the extrusion pressure as low as is practical with the material being handled.

In the present invention the high pressure pump l! is of relatively large capacity and is so y in the circuit that it serves the function. of rapidly traversing the clamping plunger and also the feeding plunger on both their forward and'return strokespthus serving the purpose of an additional low pressure booster pump. During the extrusion or injectionvstroke both the clamping and feeding plungers are at rest, with their pressure ,being held at these points by the small highpressure pump Il, and during'this forward extrusion stroke the extrusion or injec tion is carried out solely by the large high pressure pumpll. This pump I2 enables the elimination of lliash pressure devices previously used..

Itwill be understood that I desire to compre hend within my invention such modications as come within the scope of the claims and the invention. p

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is;

i. A measuring and`charg'ing device for supplying material to a machine with a'material injecting element and comprising a charging chamber. a charging member therein, a mesur'- ing casing, a screw conveyor member therein adapted when rotated to measure out and feed a 4.1 In combination. a pair of mutually engageable die members. agmolding material injector therefor. a chargingchamber for said injector. a charging member in said charging chamber for charging said injector, hydraulic plungers for fmoving said die Vmembers into engagement vwith each other and with said injector, avhydraulic plunger for operating said injector, and measuring mechanism automatically synchronized with the motion of said charging chamber plunger to measure out and supply measured charges of `molding material to said injector.

y 5. An, apparatus for injection molding heated plastic materials comprising a machine including anv injection cylinder, a casing surrounding said cylinder, and a compartment between said casing and cylinder, a charging cylinder, a casing surrounding said cylinder and a compartment between said charging cylinder and its casing, said compartments being adapted to contain fluid for interchanging heat between the same and said cylinders. a iluid container, means for .circulating the fluid from said container through said compartments, means for heating said fluid in said container, and means for by-passing a 'portion ofthe fluid past one of said compartments whereby to establish a temperature differential between said chambers.

6. An apparatus for injection molding heated plastic materials comprising a machine including an injection cylinder, a casing surrounding said cylinder, and a compartment between said casing and cylinder, a charging cylinder, a casing surrounding said cylinder and a. compartment between said charging cylinder and its casing. said compartments being adapted to contain fluid forinterchanging heat between the same and said cylinders, a iluid container. vmeans for cirfor maintaining a substantially constant temper- A ature in said fluid container.

7. An apparatus for injection molding heated plastic materials comprising a machine including an injection cylinder, a casing surrounding said cylinder, and a compartment between said casing and cylinder, a charging cylinder, a casing surrounding said'cylinder and a compartment between said charging cylinder and its casing, said compartments being adapted to contain iiuid for interchanging heat between. the same and said cylinders, a fluid container, means for circulating the uid from said container through said compartments, means for heating said iiuid in said container, means for by-passinga portion .of the fluid past one of said compartments whereby to establish a temperature diilerential between said chambers, thermostatic means for maintaining a substantially constant temperature in said iiuld container, and a valve in said by-passing means for controlling the proportionate quantity of fluid by-passed.

8. In combination, movable die means, hydrauli'cally actuated devices for moving said die means into a closed position, an injector adapted to inject molding material into said die means, a charging chamber for said injector, acharging member therein i'or charging said injector, and mechanism automatically responsive to the operation of said injector formeasuring out and distributing measured charges oi' molding material to said charging chamber.

9. In combination, movable die means, hy-

draulically actuated devices for moving said die means into a closed position, an injector adapted to inject molding material into said die means, a charging chamber for said injector, a charging member therein ior-charging said injector, and mechanism automatically responsive to the operation cf said injector for measuring out and distributing measured charges o! molding material to said charging member, said mechanism being operated upon the retraction stroke only of said injector.

10. In combination, movable die means, a directly acting hydraulic motor i'or moving said die means into a closed position, an injector adapted to inject molding material into said. die means, a charging chamber for said injector, a charging member therein forfcharging material therefrom to said injector, and mechanism operatively responsive to the operation of said injector for measuring out and distributing measured charges of molding material to said charging chamber. 1l. In combination, movable die means, a directly acting hydraulic motor for moving said die means into a closed position, an injector adapted to inject molding material into said die means, a charging chamber for said injector, a

c' charging member therein for charging material therefrom to said injector, and mechanism operatively responsive to the operation oi' said injector for measuring out and distributing measured charges oi' molding materialto said charging chamber, said mechanism being operated upon the retraction stroke only of'said injector.

12.-In combination, movable die means, a directly acting hydraulic motor forY moving said amos culating the iluid from said container through f die means into a closed position, an injector adapted to inject molding material into said die means, a charging chamber for said injector, a charging member therein for charging material therefrom to said injector, mechanism operatively responsive to the operation of said injector for measuring out and distributing measured charges of molding material to said charging chamber, and a hydraulic motor i'or operating said injector. 1

13. In combination, movable die means, a directly acting hydraulic motor ior moving said die means into a closed position, an injector adapted to inject molding material into said die means, a charging chamber for said injector, a charging member therein for charging material therefrom to said injector, mechanism operatively responsive to the operation o! said injector for measuring out and distributing measured charges of molding material to said charging chamber, a hydraulic motor i'or operating said injector, and a hydraulic motor for operating said charging member.

.14. In combination. a pair oi' mutually engageable die members, a molding material injector therefor, hydraulic plungers for moving said die members into engagement with each other and with said injector, a hydraulic plunger for operating said injector, a charging chamber for said injector, charging means associated with said chamber and synchronized with the motion of said injector plunger for charging molding material from said chamber to said injector, a hydraulic motor for operating said charging means, measuring means for measuring out and supplying measured portions of molding material to said charging chamber, and mechanism automatically synchronized with the motion oi' said injector `plunger for operating said hydraulic charging operating motor.

15. In combination, a pair oi mutually engageable die members, a molding material injector therefor, hydraulic plungers for moving said die members into engagement with each other and with said injector, a hydraulic plunger for operating said injector, a charging chamber in flow communication with said injector, charging means therein synchronized with the motion of said injector plunger for charging molding material therein to said injector, a hydraulic motor for operating said charging means, measuring means for measuring out and supplying measured portions of molding material to said charging chamber, and mechanism automatically synchronized with the motion of said injector plunger foroperating said measuring means.

16. In combination, a pair of mutually engageable die members, a moldingl material injector therei'or,'hydraulic plungers for moving said die members into engagement with each other and with said injector, a hydraulic plunger l

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