US2088134A - Die-casting and pressure molding machine - Google Patents

Description

DIE CAST ING AND PRESSURE MOLDING MACHINE Filed July 23, 1935 2 Sheets-Sheet 2 7n veidor:

Patented July 27; 1937 UNITED STATES PATENT OFFICE" Paul Haessler, Nuremberg, Germany Application July 23, 1936 Serial'No. 92,198

In Germany May 31, 1933 9 Claims. (01. 22-438) This invention relates to means for driving die-'- 7 casting and pressure molding, machines, more particularly for the movable half of the mold and the working piston. The object of the invention is toavoid the disadvantage of the known arrangements, which consist in this-that the entire motion is effected by hydraulic means, involving a great consumption of water under pressure. A further object of the invention is to obtain a more uniform drive than was possible with the devices hitherto employed.

An essential feature (if the invention is, that the closing motion of the mold half and the forward motion of the working piston till it enters the pressure chamber is effected mechanically, whilst the mold-closing pressure and the motion of the working piston for applying pressure are produced hydraulically. During the pressing operation the cylinder whichdrives the "working piston is rigidly connected with the movable half of the mold. A further feature of the invention is that, for avoiding the use. of the usual control valves, accumulators and pumps,

the liquid which serves during pressing for moving the working piston is forced back into the pressure accumulator through the working piston being moved back mechanically. According to the invention'the working piston may be held in its extreme position by a column of liquid. The cylinder chamber lying at the rear side of the piston has. an outlet which is provided with an adjustable valve. Preferably the outlet is in communication with a pressureless collecting chamber.

5 In the accompanying drawings the invention is illustrated by two constructional examples,

Figure 1 shows the driving apparatus according to the invention in a position in which the press mold is already closed and the working 40 piston for filling in the pressed material is still" in the initial position;

Figure 2 shows the same apparatus as Figure 1, with the workingpiston in the pressing position; 45 Figure 3 shows the same apparatus as Figures 1 and 2, with the press mold opened;

Figure 4 shows a modification of the means for returning the pressure liquid .into the pressure reservoir, in the .position immediately preceding '50 the pressing;

Figure 5 shows this modification in the pressing position; and

Figure 6 shows'the same modification immediately. after the backward movement of the work- 55 ing piston.

In the drawings is a portion of the machine pedestal of a die-casting and pressure molding machine. The standard supports the bars 3 and 4 which are connected to one another by a transverse member 2. On the transverse member 2 5 are sliding bearings 5 and Gfor bars l and B. 'I'heba-rs l and 8 have transverse members 3 and Ill. The transverse member 9 has its ends formed into sliding bearings II and I2 which are guided on the bars 3 and 4. In the standard 10 is provided a two-sided thrust bearing l3 in which the nut I4 is rotatable. I5 is a self-locking spindle which runs in the nut l4 and the head l6 of which is in the form of a piston. The nut I4 is connected to belt pulleys H which are 15 driven through a belt drive l8 by a driving pulley 20 mounted on the shaft of an electric vstationary half 22 of the mold, which is in com-,

munication with the press bore 2| is fixed to the transverse member 2. The press bore 2| is 5 continued in'the form of a slide channel 23, to

which, through anopening 24 the material to be pressed is fed. On the forward side of the transverse member 9 arev two brackets 25, to which the movable half 26 of the mold is screwed. 30 On the rear side of the transverse member 9 is a cylinder 21 in which the piston I6 can move with a stroke of about 10 mm. In the slide channel 23 a working piston 28 is slidable. The working piston 28 is mounted on a rod 29 of a pressure piston 30.- The pressure piston is disposed in a cylinder 3| which is supported by a transverse member 32 which with the aid of sliding bearings 33 'and 34 is slidable on the bars 1 and 8. On the bottom of the cylinder 3| and on the transverse member ID are brackets; between which a toggle lever arrangement 35 is disposed, which can be buckled and extended by means of a piston 31 moving in a cylinder 36.

.On the transverse member 32 are extensions 38 which strike against adjustable abutments 33. and the bars 3 and 4, whereby the forward stroke of the cylinder 3| is limited. A pressure water reservoir 43 which is loaded bycompressed air reservoir 42 is connected to apressure pipe 44.

45 is a return pipe, through which the pressure liquid flows back, after performing work, into the collecting vessel 46. Out of this collecting vessel48 the pump 43 pumps the liquid into the pressure vessel 42. By way of the pipe 45 the two ends of the cylinder 36 and the forward ends of the cylinders 21 and 3| are supplied with water under pressure. The distribution of the pressure water is effected by means of control members 41, 48 and 49. These control members are displacedpositively with the motion of the machine.

Fig. 1 shows the arrangement in the position after the closing of the mold and the withdrawal of the pressure piston. Through the nut |4 being turned to a suitable extent the spindle i5 will have moved forward, the piston it will have laid itself against the end of the cylinder 21 and consequently the transverse member 8 together with the brackets and the movable half 26 of the mold will have slid forward against the stationary half 22 of the mold. The motion of the transverse member 9 will have been shared by the parts i,

8 and I8 and consequently by the cylinder 3| 25 which issupported on the bars I and 8. On the halves of the mold meeting, the control members 41 and 48 will have been displaced. The dis placement of the control member 41 establishes the connection of the pressure water accumulator 30 42 with the front part of the cylinder 21', causing the closing pressure of the mold to take effect. By the displacement of the control member 48 pressure water will have been supplied to the cylinder 3|, so that the pressure piston 38 will have been forced backwards and the pressure liquid in the rear part of the cylinder will have been displaced into the pressure water accumulator 48. The working piston 28 will thus have reached its rearward position.

Thereupon the slide channel 23 is'fed with the material to be pressed. Through reversing the control member 48 the lower part of the cylinder 38 is connected with the pressure water accumulator 42. The piston 31 moves upwards and extends the toggle lever arrangement 35. By this means the cylinder 3| and the working piston 28 are moved into the position I shown in Fig. 2 and the material is pushed forward out -of the slide channel 23 into the press bore 2|. In this position the control member 48 connects the front space of the cylinder 3| with the return pipe 45. The pressure piston 38 which is under the pressure of the pressure water accumulator 48 and together with it the working piston 28 move forwards, the material being forced out of the press bore 2| by casting it andshearing ofl into the interior of the mold. The piston 28 now occupies the position II. During the opening of the mold, which immediately follows, the working piston 28 continues to move in the pressing direction and ejects the residue of material remaining in the press bore 2|. i

After the mold has been opened the parts of the arrangement occupy the position shown in Fig. 3. For eil'ecting the opening the two shut-off members 41 and 48 are first changed over insuch a manner that the cylinder 21 and the lower space in the cylinder 38 are connected with the return pipe .45. Simultaneously with this operation the nut i4 is turned back, causing thespindle I! to move backwards. The piston l8 lays itself against the closure of the cylinder 21. The transverse member 8 together with the brackets 25 and the movable half 28 'of the mold take part in the rearward motion. The motion of the transverse along a member.52 which is slidable on the piston 2 member 9 is shared by the bars i and 8 and the rear transverse member I8. For forcing the cylrangement 35 lags slightly behind that of the parts 1, 8, 9 and ID. The result of this is, that 10 the cylinder 3| will not prematurely leave the stops 39.

This operation is followed by the closing of the mold and the return motion of the working piston, the parts occupying the position shown 15 in Fig. 1.

Whilst in the constructional form according to Figs. 1 to 3 valves and a pump are provided for returning the liquid to the pressure vessel, in the constructional form shown in Figs. 4 to 6 the 20 return of the liquid is effected by a mechanical backward motion of the working piston. For this purpose the piston rod is provided with a flange 5| which acts as an abutment for carrying rod 29. This member 52 is connected to a rack 53 which is displaceable by means of an electric motor 51 through a pinion and worm drive 54, 55 and 56. The forward part of the space in the cylinder 3| has an outlet 58 which is in com- 30 munication by way of a controllable non-return valve 59 with a pressure-free vessel 68.

Fig. 4 shows the arrangement immediately before the pressing operation. The pressure exerted by the liquid from the pressure chamber 48 35 on the pressure piston 88 causes the valve 58 to close, so that the working'piston 28 remains in the position shown. Forpressing, the valve 59 is,

as shown in Fig. 5, opened by pressure being exerted on the control bar 8| and the water can 40 flow from the front part of the cylinderback into the vessel 88. Under the pressure of .the liquid in the pressure vessel 48 the working piston moves to the left; According to the amount the valve 58 opens the motion of the piston will 45 be quicker or slower. If the valve 59 is controlled in such a manner that for a certain portion of the forward motion of the piston 38 it allows only a small quantity of water to flow out and for the remaining portion a large amount 50 of water, the working piston will at first move only slowly, but during the last part of its path, which is the part that is of importance for the actual pressing operation, more quickly.

Fig. 6 shows the backward motion-of the pis 55 ton 38. Under the action of the pinion and the rack the member52 is caused to bear against the flange 5| and takes the piston rod 29 and the piston 38 along with it to the right. The piston'38 forces the water out of the rear end of 60 the cylinder into the accumulator 48, whilst through the automatically opening valve 59 water flows back out of the vessel 88 into the front part of the cylinder. When the piston 38 has reached the position shown in Fig, 6, the motor 65 51 is reversed, whereby the rack is brought back again into the position shown in Figs. 4 and 5. The motor is then cut oif.

The mechanical gearing of the constructional form shown in Figs. 4 to 6 can also be con- 70 structed in another way. The screw spindle drive which effects the displacement of the movable half of the mold could .also be replaced by any other mechanical drive. The screw spindle driveis however preferred, as the force to be 75 enemas given on by the spindle is the same in all positions, in contradistinctionto a crank, eccentric or toggle lever drive. Between the spindle and V the motor driving the spindle a slip coupling is with advantage interposed, preferably a hydraulic oil coupling, in order to prevent the mo tor and the machine being overloaded? What I claim is:- I .1. In a pressure molding device a pressing mold having a movable part and anon-movable part, mechanical means ;for moving thesaid movable part, a charging channel on the said non-movable part, a pressure cylinder movable towards and away from the non movable part of the mold, a pressing piston slidable in the said pressure cylinder; a working piston and movable along the said charging channel,

connected to the said pressing piston and mov able along thesaid charging channel, means capable of moving the pressure cylinder and the working piston into the closing position and for actuatingthejpressing piston in the pressure cylinder and thereby moving the working piston into the pressing position.

2. In a pressure molding device a pressing mold having a non-movable part, a charging Y channel on the said non-movable part, an axially displaceable pressure cylinder in line with the charging channel, a pressing piston axially displaceable in said cylinder, 9. working piston rigidly connected with the said pressing piston means adapted'to move the movable pressure cylinder and the working piston into the closing position and means for actuating thepressing piston in the pressure cylinder and thereby moving the workingpiston into the pressing position.

3. A pressure. molding device as 'claimed in claim 2, -and in which the-said meansfor actuating the pressing piston comprise a storage vessel containing asupply of liquid under pressure and a pipe connecting said vessel with the, rear pressure space offth'e said pressure cylinder.

4. A- pressure molding device as claimed in claim 2 and in which the said means adapted to move the movable pressure cylinder comprise a spreading device having two pressure applying bars adapted, when in the spread position, to

5. A-presure molding device as claimed in hold the said pressure cylinder rigidly.

claim 2 and in which the said means adapted'to move the movable pressure cylinder comprise a spreading device having two pressure applying bars adapted, when in the spread position, to

hold thensaid pressure cylinderj rigidly. and a hydraulic pressure arrangement for moving the I pressure bars.

6. In a pressure molding device a pressing mold having a non-movable part, a charging channel on dhe said non-movable part, an axially displaceable pressure cylinder in line with the- .charging channel,a pressing piston axially displaceable in said cylinder, 9. working piston rigidly connected with the said pressing piston and movable along the said charging channel,

means adapted to move the movable pressure cylinder and the working piston into the closing position, means for actuating the pressing piston in the pressure cylinder and thereby moving.

the working piston into the,pressin'g position, and mechanical means, capable of returning the pressing piston into the initial position.

. 7. In a pressure molding'device as claimed in claim 6, an outlet at the forward pressure space of the said pressure cylinder andon the said 1 the said outlet.

9. In a pressure molding device as claimed in claim 6, an.outlet at the forward pressure space 01' the said pressure cylinder, on the said outlet a non-return valve adapted to control the escape oi. liquid from the forward pressure space, the said mechanical means for returning the a pressing piston comprising a connecting rod,

connected to the pressure piston a piston rod,

an abutmenton'the said piston rod, a' driving"v member on the s'aidconnecting rod ,which is adapted to engage the abutment member on one side and driving means for moving the. said connecting rod to and fro. f

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