US2269389A - Molding press - Google Patents

Description

-L/i zm ik f7 l Jan. 6, 1942 M. F. WEIDA 2,269,389

MOLDING PRESS Y Filed March 4, 1958 s sheets-sheet 1 O mumllull'llmlf 12 l Il" l www" MW f4 www l 2 l 45 Il 1 i# 5, 55- 32 20T 40 59 3, l graue/Moz Fly] f './l/illdmhida l I MW Jan. 6, 1942 M. F. WEIDA4 MoLDING PRESS I Filed March 4, 1938 5 Sheets-Sheet 2 -ulwwwfj -i W w s d 1 um Jan. 6, 1942 M. F. wElDA 2,269,389

MOLDING PRES S Filed March 4, 1958 s sheet-sheet s Patented Jan.. 6, 1942 UNITED STA-'111515 PATENT l 0F F I CE* 2,2695@ f MOLDING Plls MillardF. Weida, near Louyisyille, Ohio l Appiiatipn March 4, issaserial isp. 179:3.,95-

v9 Claims.

The invention relates to presses forv molding plastics such as rubber, Bakelite and the like, and the object of the present invention is to provide a press of this character with meansfor rapidly bringing the mold sections nearly to closed .posil tion under low pressure and then more slowly closing the moldsy under high pressure.

Another object is to provide a press of the type referred to arranged to be operated by fluid cyl-'- inders with means for holding the mold sections in closed position under high pressure so that the fluid cylinders may be released when the mold` sections are closed.

A further object is to provide a molding press in which the mold sections are arranged to `be clcsedby toggle levers, two fluid cylinders being arranged to successively operate to move the' levers to the closed position.

A still further object of the improvement is lto provide means whereby the secondr or high pressure cylinder will be automatically operated when the toggle'levers reach a predetermined position.

Still another object is to provide means forautomatically controlling the operation of the cylinders so as to move the parts throughacomplete cycle each time the press is started.

The above objects together with others which will be apparent from the drawings and followthe upper ends vof the guide rods as by the nuts yI3'loc`ated ponthe threaded upper' ends I4 of the rods, Washers I5 ofl any desired thickness being interposedbetween ther cross-head and the iixedcollars or shoulders I6 of the rods.

' The upper vor fixed mold section is adapted to l be attached to the cross-head I2 as by the T-grove I8. "The lower'mold sectionV is adapted tobe attached in` the same mannerto thel block l 9 which is slidably mounted upon the guide rods I Ian'd'provided with the T-grooves 20.

- iflpair oftogglelevers 2 I land 22 is provided for raising and lowering the block I 9 upon the guide rods, the upper lever 2 I being pivotally connected ing description or which may be later referred to,

may be attained by constructing the improved molding press inthe mannerl illustrated in the accompanying drawings in which:

Figure lis a side elevation, partly in section of a molding press constructed in accordance kwith the invention, showing the parts in the open or s initialposition; v

Fig. 2, a fragmentary sectional elevation similar to Fig. 1 showing the partsA in the vclosed or operated position; f'

Fig. 3, a transverse sectional elevation of the press taken on the line -3-3 Fig. 1;

Fig. 4, a detached, perspective View of the bifurcatedhead which'forms a connection'between the toggle levers and the second fluid cylinder; and

Fig. 5, a diagrammatical view showing the cylinders, valves and electric wiring forV operating the press.

Similar numerals refer to 'similar throughout the drawings.

The base of the press is in theform of a housparts ing I0 within which is enclosed the operatingl mechanism. i Four spaced upright guide rodsfll are secured at their lower ends to the housing I0 and a `cross-head I2 is adjustably,mountedupon tothe sliding block as by pin 23 located through the upperendo'f'the lever and `through the depending lugs 24 formed upon the block.

The '.togglelevers' v'2-I and ,22 are pivotally connected-together as by the pin 25 and the lower lever 22 is fixedV upon a shaft 26 journaled in bearings .2l.located within the housing I0 and preferably suspended ,from the cover plate 28 thereof as by the Webs 29. l

Thelever 2| maybe adjustable in length as by means of vthe'oppositely threaded screw. 30 locatedat.itsintermediateportion and received in .the split4 internally threaded sockets 3I provided Withllam'pi'ng'screws321for holding any desired adjustment, a squared or hexagonal head 33 being formed atthe central portion of the Oppositely threaded screw to`receive a wrench orLthe like for @adjusting rthe same. This adjustment provdesfor. the use `of mold sections of varying thicknesses.

- Apinion 34 is fixed upon the shaft 26and may be formed integrally with the .lever 22 vas best shown injFigs. 1 and 2. 'I'his pinion meshes with arack bar35, slidable within a guidewayn36 which may be. formed integral withthe bearings 2l and supported by the webs 29. l

Afluid operated low pressure cylinder. 3l is mounted within the bottomof the housing I0 and .the piston rody 38. thereof is fixed to the rack bar 35 solthatithe rack bar is reciprocated within its guide when thecylinder isoperated.

Ahighlpressure fluid operated cylinder 39 is locatedV in the upper portion of the housing and thel piston.. rod,40 thereof has the yokev 4I fixed to its outer end. This yoke is arranged to straddley the toggle rlevers and/fis mounted to slide within guides I2A formed in the cover plate28 of thehousing. n

The lever 22 has an oir-set portion 43 at its o uter end through which is located a pin 44 extending outward .toeach side of thev lever and 2 adapted to be received in the notches 45 of the yoke 4| as will be later described.

In order to automatically operate the press through a complete cycle each time the same is started, a series of valves and switches as diagrammatically shown in Fig. 5 may be provided for operating the low and high pressure cylinders at the proper times.

The cylinders are adapted to be operated by means of a pump 46 connected with a reservoir or tank 41 and with a four-way valve 48 arranged to selectively admit uid under pressure to either end of each of the cylinders 31 and 39.

The pump 46 may be driven by an electric motor 49 which is adapted to be operated through a reversing switch indicated generally at 50 by means of the three-phase circuit comprising the wires 5l, 52 and 53 leading from any suitable source of electric energy. I

The four-way valve 48 is connected by a pipe 54 with the tank 41 and is also connected by a pipe 55 with the three-way valve 56. A pipe 51 leads from the four-way valve to the forward end of the low pressure cylinder 31, and a pipe 58 communicating therewith and having the speed control device 59 located therein leads to the three-way valve 56 which is connected as by the pipe 60 with the rear end of the high pressure cylinder 39.

A pipe 6| leads from the four-way valve 48 to the forward end of the high pressure cylinder 39 and communicates with the pipe 62 which leads to the rear end of the low pressure cylinder 31.

The three-way valve 56 is arranged to be operated by a pilot valve indicated generally at 63 and connected by a pipe 64 with the pump 46.

Pipes 65 and 66 are arranged to provide communication between the pilot valve 63 and opposite ends of the three-way valve 56 so that oil pressure from the pump through the pipe 64 may be conveyed through the pilot valve 63 to either end of the three-way valve 56 in order to seat the same in either operative position.

A hand operated lever 61 is provided for throwing the four-way valve 48 to either position and is operatively connected to a pair of double pole switches indicated generally at 68 and 69 and adapted to be operated by a solenoid 10.

The reversing switch indicated generally at 50 comprises two multiple blade switches 1| and 12 for operating the motor 49 forward and in reverse respectively, these switches being arranged to be operated by the magnets 13 and 14 respectively.

Line wires 5|, 52 and 53 are connected to the contact points 15, 16 and 11 respectively of the forward side of the switch and the corresponding contact points 18, 19 and 80 respectively are connected as by the wires 8|, 82 and 83 to the motor 49, the switch blades 84, 85 and 86 respectively being adapted for closing the circuit from the line wires through these wires to the motor to operate the same forwardly.

. 'I'he line wires are similarly connected'to the contact points 81, 88 and 89 of the reversing side of the switch and the corresponding contact points 90, 9| and 92 are connected by the wires 93, 94 and 95 respectively to the motorA 49, and the blades 96, 91 and 98 respectively being adapted to close the circuit from the line wires to the motor to operate the same in reverse.

The solenoid operated switch 68 has two blades 99 and 99a, the blade 99 closing a circuit through the magnet 13, normally closed plunger switch |0| and switch blade |06 of the starting switch. The normally open plunger switch |02 controls a circuit through the magnet 14 on the reversing side of the reversing switch 50.

A timer |03 is provided in the circuit for controlling the period during which the mold sections remain closed in each cycle of operation of the press. A magnet operated switch |04 is adapted to be operated by the timer.

To start the automatic operation of the press, the switch blade |00 on the push-button station is thrown to the auto position. The starting switch |05 is closed and the lever 61 of the fourway valve 48 is thrown to the forward position.

'The circuit to the motor 49 is closed through the forward side of the reversing switch 50 by the closing of the one set of contacts through the blade 99 of the double pole switch 68 which energi'zes the magnet 13 closing the multiple blade switch on the forward side of the reversing switch 50. Through the other blade 99a. of the switch 68 the circuit is closed through the timer |03.

The four-way valve 48 has thus been operated by moving the lever 61 forward to admit fluid to the forward end of the low pressure cylinder 31 driving the piston rod 38 thereof inward and reciprocating the rack bar 35 in the direction of the arrows shown in Figs. 1 and 5 operating the toggle levers 2| and 22 rapidly to raise the sliding block I9 almost to the position where the die sections are closed.

As the toggle levers reach a position where the pins-44 on the lever 22 are received into the notches 45 in the sliding yoke 4| further movement of the toggle levers in this direction will slide the yoke 4| a slight distance in the direction of the arrow shown in Fig. 5.

The finger |06 upon the yoke operates the pilot valve 63 to admit oil under pressure to the threeway valve 56 to set said valve in position to admit fluid to the rear end of the high pressure cylinder 39 which continues the movement of the yoke 4| in the direction of the arrow slowly closing the mold sections under high pressure and throw- 4 ing the pivot 25 of the toggle levers over center at which time the plunger switch |0| is opened by contact with the yoke 4|.

It will be seen that the plunger switch |02 will close as soon as the Vtoggle levers first start to operate. The opening of the plunger switch |0| breaks the circuit to the motor, stopping the same and holding the dies closed Without operation of the fluid pressure cylinders.

At the end of the set time-the timer will operate to energize the magnet |08 closing the switch |04 which in turn energizes the solenoid 10 which pulls the valve lever 61 to the reverse position breaking Contact of the blade '|09 of the switch 69 and closing contact by the blade ||0 of said switch, pulling the reversingY switch to the reversed position, starting the motor in reverse, and stopping and resetting the timer. The valves are thus operated to reverse the flow of fluid through the cylinders 31 and 39 to bring the toggle levers 2| and 22 back to the initial position and as they reach this position they will automtically open the plunger switch |02 stopping the motor.

The machine Will now remain idle until the oil valve lever 61 is again moved to the forward position starting another cycle of operation.

Although the arrangement of valves, pipes and electric wiring and switches diagrammatically shown in Fig. 5 has been found in practice to be very satisfactory for automatic operation for the improved molding press, it is pointed out that e acca-'seo there may be many-other arrangements of valves and wiringY by means of which th'epr'e'ss may be operated but this one arrangement is 'shown to illustratev completely the operation of the press which in itself forms the subject matter of the present invention rather than any particular electrical or fluid control means. t

I claim:

l. iA molding press including a stationary mold section, va movable mold section, a pair of 4toggle levers pivotally connected together, one lever being pivotallyconnected to said movable 4mold sec'- tion, a rotatable shaft'uponwhich'the other lever is Xed, a fluid cylinder for .rotating said lshaft to move `the toggle levers until the mold. sections are nearly closed, a second 'cylinder having a piston rod, a valve forv controlling theadmission of fluid .to the second fluid cylinder, pin and shoulder means upon rsaid 'piston rod and upon oneof said levers adjacent to the pivotal joint of said levers, positioned to be interengaged upon movement of said toggle levers to close the mold sections, said shoulder being `moved by said pin while being so: interengaged and means on said piston rod and movable by said shoulder for opening said valve to admit fluid .to the second fluid cylinder when the pin engages and moves the shoulder whereby the last named piston rod will further move the toggle levers in order to fully close the mold sections.

2. A molding press including a stationary mold section, a movable mold section, a pair of toggle levers pivotally connected together, one lever being pivotally connected to said movable mold section, a rotatable shaft upon which the other lever is fixed, a fluid cylinder for rotating said shaft to move the toggle levers until the mold sections are nearly closed, a second fluid cylinder having a piston rod, a valve for controlling the admission of fluid to the second fluid cylinder, and pin and shoulder means upon said piston rod and upon one of said levers adjacent to the pivotal joint of said levers positioned to be interengaged upon movement of said toggle levers to close the mold sections, said shoulderbeing moved by said pin While being so interengaged and means on said piston rod and movable by said shoulder for opening said valve to admit fluid to the second fluid cylinder when the toggle levers reach a predetermined position and when the pin engages and moves the shoulder whereby the' second fluid cylinder will further move the toggle levers in order to fully close the mold sections.

3. A molding press including a stationary mold section, a movable mold section, a pair of toggle levers pivotally connected together, one lever being pivotally connected to said movable mold section, a rotatable shaft upon which thev other lever is fixed, a fluid cylinder for rotating said shaft to move the toggle levers until the mold sections are nearly closed, a pin upon one of the levers, a second fluid cylinder having a piston rod' provided with a shoulder positioned to be engaged by said pin and to be moved thereby upon movement of said levers to close the mold sections, a valve for controlling the admission of fluid to said second fluid cylinder and means upon the piston rod of the second fluid cylinder for operating the valve when the pin engages the shoulder upon the piston rod and moves the piston rod whereby the piston rod will further move said toggle levers in order to fully close the mold sections.

4. A molding press including a stationary mold section, a movable mold section, a pair of toggle levers pivotally connected together, one lever berod provided with a shoulder positioned to be engaged by said pin and be moved thereby upon movement of said lcvers-to close the mold sections, a valve for controlling the admission of fluid to said second fluid cylinderl and means upon the piston rod of the second fluid cylinder for operating the valve when the pin engages the shoulder upon the piston rod and moves the piston rod whereby the piston rod will further move said toggle levers over center in order to fully close the mold sections and hold them inclosed position, and means for then stopping the operation of the fluid cylinders.

5. A molding press including a static-nary mold section, a movable mold section, a pair of toggle levers pivotally connectedtogether, one lever being pivotally connected to said movable mold section, a rotatable shaft upon which the other lever is fixed, a fluid cylinder for rotating said shaft to move the toggle -levers until the mold sections are nearly closed, a pin upon one of the levers,

a second fluid cylinder having a piston rod provided with a notch positioned to be engaged by said pin and be moved thereby upon movement of said levers t0 close the mold sections, a valve for controlling admission'of fluid to said second cylinder and means upon the piston rod of the second fluid cylinder for operating the valve when the pin engages said notch and moves said piston rod whereby the piston rod will further move said toggle levers in order to fully close the mold sections.

6. A molding press including a stationary mold section, a movable mold section, a pair of toggle levers pivotally connected together, one lever being pivotally connected to said movable mold section, a rotatable shaft upon which the other lever is fixed, a fluid cylinder for rotating said shaft to move the toggle levers until the mold sections are nearly closed, a pin upon one of the levers, a second fluid cylinder having a piston rod provided with a notch positioned to be engaged by said pin and be moved thereby upon movement of said levers to close the mold sections, a valve for controlling the admission of fluid to said second cylinder, means upon the piston rod of the second fluid cylinder for operating the valve when the pin engages said notch and moves the piston rod whereby the piston rod will further move said toggle levers over center in order to fully close the mold sections and hold them in closed position, and means for then stopping the operation of the fluid cylinders.

7. A molding press including a stationary mold section, a movable mold section below the stationary mold section, a pair of toggle levers pivotally connected together, the upper end of one lever being pivotally connected to the movable mold section, a rotatable shaft upon which the lower portion of the other lever is fixed, a fluid tioned to be interengaged upon movement of said toggle levers to close the mold sections and means upon the piston rod of the second uid cylinder for opening the valve to admit fluid to the second fluid cylinder when the pin and shoulder means interengage and move said piston rod whereby the last named piston rod will further move the toggle levers to fully close the mold sections.

8. A molding press including a stationary mold section, a movable mold section below the stationary mold section, a pair of toggle levers pivotally connected together, the upper end of one lever being pivotally connected to the movable mold section, a rotatable shaft upon which the lower portion of the other lever is fixed, a low pressure fluid cylinder operatively connected to the last named lever below said shaft for moving the toggle levers until the mold sections are nearly closed, a high pressure fluid cylinder having a piston rod, a valve for controlling the admission of fluid to the high pressure fluid cylinder and pin and shoulder means upon said piston rod and upon one of said levers adjacent to the pivotal joint of said levers positioned to be `interengaged upon movement of said toggle levers to close the mold sections and means upon the piston rod of the high pressure fluid cylinder for opening the valve to admit iluid to the high pressure fluid cylinder when the pin and shoulder means interengage and move said piston rod whereby the last named piston rod will further move the toggle levers to fully close the mold sections.

9. A molding press including a stationary mold section, a movable mold section, a pair of toggle levers pivotally connected together, one lever being pivotally connected to said movable mold section, a rotatable shaft to which the other lever is fixed, a gear upon said shaft, a low pressure fluid cylinder having a piston rod, a rack upon said piston rod engaging said gear for rotating said shaft to move the toggle levers until the mold sections are nearly closed, a pin upon one of the levers adjacent to the pivotal joint of the levers, a high pressure fluid cylinder having a piston rod provided with a shoulder positioned to be engaged and moved by said pin, a valve for operating the high pressure fluid cylinder, and means upon the piston rod of the high pressure cylinder `for opening the valve and starting the high pressure fluid cylinder when the pin engages and moves said shoulder whereby the last named piston rod will further move the toggle levers in order to fully close the mold sections.

MILLARD F. WEIDA.

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