US2862266A - Pressure diecasting machine - Google Patents

Description

Dec. 2, 1958 PERAs' PRESSURE DIECASTING MACHINE 2 Sheets-Sheet 1 Filed June 1, 1956 Dec. 2, 1958 L. PERAS ,2

PRESSURE DIECASTING MACHINE Filed June 1, 1956 2 Sheets-Sheet 2 2 ,862,266 Patented Dec. 2, 1958 PRESSURE DIE'CASTIN G MACHINE Lucien Peres, Billancourt, France, assignor to Regie Nationale des Usines Renault, Billancourt, France Application June 1, 1956, Serial No. 588,653

Claims priority, application France June 23, 1955 6 Claims. (Cl. 22--68) The invention relates to improvements to machines for casting any materials, and more particularly metals, under pressure.

The present-day machines, whether they are of the cold chamber type with an injection pressure of 500 to 1,000 kg./cm. and above for aluminium, brass or steel, or of the hot chamber type with an injection pressure of the order of 150 kg./cm. for white metals, consist of a press section and an injection section. The necessary movements in the two sections are obtained by the operation of pneumatic cylinders for the low power machines and hydraulic cylinders for the highpower machines. Compressed air at a pressure of 7 to 15 kg./cm. or a liquid under a pressure of 15 to 20 kg./cm. or of 80 to 150 kg./cm. are then used respectively.

The use of compressed air permits the use of simple apparatus in which leakages do not present any serious inconvenience. But high injection pressures cannot be obtained because of the size of apparatus which would then be necessary with the low pressure used. Moreover, the compressibility of air does not permit of precise regulation of the speed of injection into the mould. On the other hand, oil or water under pressure enable powerful machines to be made with precise regulation of the speed of injection. But this is only achieved by the addition of high pressure pumps, from which the following disadvantages result: The pumps either take up a great deal or" room, in the case of conventional transmission (piston, connecting rod, crank), or are fragile, and their upkeep is very expensive. These disadvantages are found in all the other pumps of small dimensions. The improvements according to the invention permit the initial use of only one fluid at low or medium pressure, either compressed air in the case of small machines, or oil or water in the case of large machines.

Said improvements consist in using a machine which, during operation of the press (closing, opening) draws in the fluid and delivers it at high pressure to a hydro or oleo-pneumatic accumulator. This high pressure fluid is then used to produce the injection of the metal.

As a result, the disadvantages mentioned above are overcome and at the same time the machine benefits from the following advantages: 7

(a) Improved efiiciencySome of the energy lost during the closing and opening of the press is recovered in the form of oil or water under pressure.

(b) The hydraulic circuit only comprises simple apparatus: Medium pressure pump, easy to construct, not very large, maintenance therefor low; electrically controlled valves; slide valves or clack valves; pressure regulator.

An excess of high pressure oil may be provided to actuate the hydraulic jacks of the moulds (case of a pneumatic machine).

Experiments have shown that with the arrangement forming the subject of the invention, a considerable economy in energy was also obtained.

The invention will be better understood by referring to the accompanying drawings in which:

Fig. 1 shows a supply diagram of a pneumatic pressure diecasting machine; 4

Figure 2 shows a supply diagram of a hydraulic pressure diecasting machine;

Figure 3 shows a supply diagram of a hydraulic machine of the prefilling type.

Referring to Figure l, a line 1 supplies compressed air to a distributor 2 which enables said air to be transmitted through the lines 3 and 4 to the two ends of the cylinder 5, the piston 6' of which is connected to a crosshead 7 in turn connected to the pistons 8, 9 of the cylinders 10, 11. The piston 6 is the piston which, by means of the crosshead 7, eitects the closing of the mould. A reservoir for liquid (generally oil) is connected by the pipe 13 to the right-hand portion of the cylinders 14) and 11; a non-return valve 14 being mounted in said pipe 13. Said reservoir is likewise connected to the lefthand portion of the same cylinders 10 and 11 through the pipe 15 on which is mounted the non-return valve 16.

In the pipes 13 and 15, between the valves 14, 16 and the cylinders 10 and 11, there is provided a bypass consisting of the pipes 17, 18, in communication through the pipes 12, 2d, 21 with the hydraulic accumulator 22; non-return valves 23, 24 being mounted in the pipes 17, 18. A pressure-relief valve 25, set to a given pressure, is provided in the pipe 24} and permits the return of the oil to the reservoir 12 in case of excess pressure. A pressure-gauge 26, connected to the pipe 20, indicates the pressure. An electrically operated distributor valve 27 comprises a connection chamber 28 which enables the necessary connections to be established, on the one hand with the injection cylinder 29 through the pipes 30, 31 (the piston 32 of this cylinder controls the injection) and, on the other hand, with the pipes 20 and 33 which lead into the reservoir 12.

The operation of the device is as follows:

The distributor 2 is displaced in such a manner as to permit the compressed air arriving through the line 1 to pass through the pipe 4 into the cylinder 5 and to displace the piston 6 towards the left, which corresponds to closing the press.

During this operation, the pistons 3 and 9:, in the cylinders 10, 11 take in oil from the reservoir 12 through the pipe 13 passing through the non-return valve 14 and drive the oil in the left-hand compartments of the cylinders 10 and 11, at high pressure, through the pipe 15, the pipe 18, the valve 23, the p'pe 19, the pipes 20 and 21, into the oleo-pneumatic accumulator 22.

The operation of the combined electro-magnetic pilot valve and pressure-responsive distributor unit 27,28, causes the injection of the metal by affording a. passage for the. high pressure oil from the accumulator 22 to the cylinder 29, the piston 32 of which is displaced down: wardly.

The reverse operation of the combined electro-magnetic pilot valve and pressure-responsive distributor 27, 28 and of the distributor 2, restores the machine tov its initial. position. The pistons 8 and 9, being displaced towards.

V the right at the same time as the piston 6, draw in from the reservoir 12 through the pipe 15 and. the non-return. valve 16, while the same pistons force the oil through the pipe 13, the pipe 17, the valve. 24 and the pipes 19, 20 and 21, into the accumulator 22.

The regulator 25 enables the high pressure to be regulated to the desired value; this pressure is indicated by the pressure gauge 26.

Figure 2 illustrates'a modified embodiment in. which a pump 34 is associated with the reservoir 12 and forces the oil at a medium pressure; intothe, oleo-pneumatic accumulator 36, said pressure being given by the pressuregauge 37 and regulated by the regulator 38. The combined electro-magnetic valve and distributor 39 is in communication, on the one hand with the pipe 40 leading to the reservoir 12 and with the pipe 41 likewise leading to the reservoir 12 and in which is mounted the pressure regulator 38, said pipe 41 communicating with the pipe 35 connecting the pump 34 to the medium pressure accumulator 36.

' The combined electro-magne'tic valve and distributor 39 is also in communication with the pipes 42, 43, leading to the two ends of the cylinder 44, the piston 45 of which is connected to the mould-closing crosshead 46. This crosshead 46 is rigidly connected to the pistons 47, 48, which are displaced in the cylinders 49, 50. The lefthand ends of the cylinders 49, 50 are in communication, through the pipes 51, 52, with the pipe 53 in which is inserted the non-return valve 54, with the pipe 55 leading into the pipe 56, in communication with the combined electro-magnetic valve and distributor 57.

The right-hand ends of the cylinders 49, 50 are in communication, through the pipes 58, 59, with the pipe 60 in which is inserted the non-return valve 61, and with the pipe 55. Connected to the pipes 53, 60 are the bypasses 63, 62, which communicate with the pipe 66 leading into the reservoir, with the interposition of the pressure regulator 67. A pressure-gauge 68 enables the pressure to be read. Welded to the pipe 66' is the pipe 69 which is in communication with the high pressure accumulator 70. The latter is in communication with the combined electro-magnetic valve and distributor 57 through the pipe 71. valve and distributor 57 is in communication through the pipes 72, 73 with the ends of the cylinder 74, of which the piston 75 produces the injection. A pipe 76 brings the combined electro-magnetic valve and distributor 57 into communication with the pipe 77 which leads into the reservoir 12.

The operation of the device in Figure 2 is as follows:

The pump 34 drives the oil from the reservoir 12 into the medium pressure accumulator 36, the pressure of which is checked on the pressure gauge 37 and regulated by the regulator 38. The combined electro-magnetic valve and distributor 39 enables the oil from the accumulator 36 to be directed through the pipes 35, 41 into the cylinder 44, the piston 45 of which displaces the crosshead 46 and causes the closing of the mould at the same time as, during this displacement, the pistons 47, 48 in the cylinders 49, 50 take in oil from the accumulator 36 through the pipes 58, 59, 60, the valve 61, the pipes 55 and 35. During this operation, the pistons 47, 48 drive the oil under high pressure into the accumulator 70 through the pipes 51, 52, 53, 62, the valve 66, the pipes 66' and 69. The operation of the combined electromagnetic valve and distributor 57 aflords a passage for the oil from the accumulator 70 into the cylinder 74 through the pipes 71, 73, which displaces the piston 75 downwards and causes the injection of metal into the mould.

The reverse operation of the combined electro-magnetic valve and distributor 57 and then of the combined electromagnetic valve and distributor 39 restores the various members of the machine to their initial position. The oil, under medium pressure in the accumulator 36, passes through the pipes 35, 41 and 43 into the cylinder 44. At the same time, the pistons 47, 48 are displaced towards the right by medium pressure oil from the accumulator 36, passing through the valve 54, the pipes 53, 51 and 52. The same pistons 47, 48 send oil under high pressure through the pipes 58, 59, 60, 63, the valve 65, the pipes 66' and 69 into the high-pressure accumulator 70.

The regulator 67 enables the high pressure to be regulated to the desired value, which pressure is read ofi on the pressure gauge 68.

Figure 3 shows a modified embodiment applicable in The combined electro-magnetic particular to the arrangement in Figure 2 where a medium pressure accumulator and a high pressure accumulator are provided. As a result of the construction in Figure 3,

the injection movement of the molten metal takes place at the beginning with medium pressure fluid and ends with high pressure fluid, thus ensuring the most economical operation of the machine and perfect filling of the mould.

The medium pressure and high pressure accumulators are indicated respectively at 36 and 70. The combined electro-magnetic valve and distributor associated with the injection cylinder 74 is illustrated at 78. The medium pressure accumulator 36 is in communication with the top of the cylinder 74 through the pipe 79 in which is inserted the non-return valve 80. The high pressure accumulator 70 is in communication with the cylinder 74 through the pipe 81, with the interposition of a timedelay device 82.

The operation of the combined electro-magnetic valve and distributor unit 78 establishes the circuit from the medium pressure accumulator 36 to the cylinder 74, passing through the non-return valve 80.

The injection takes place by displacement of the piston 75.

During this operation, the hydraulic time-delay device 82 is actuated and after a pre-set time establishes the circuit from the high pressure accumulator 70 to the cylinder 74, the valve 80 being closed.

The reverse operation of the combined electro-magnetic valve and distributor 78 restores the piston 75 to its initial position under the action of the medium pressure.

The time-delay device 82 may be replaced: by a successive action valve, by an electric control, by a mechanical control.

It remains understood that the arrangement forming the subject of the invention apply to any pressure diecasting machine and even to any machine in which jacks have to be supplied with high-pressure fluid.

I claim:

1. In a fluid operated die-casting machine having a pressure space for molding molten metal therein under pressure, in combination, a cylinder, 2. press piston in said cylinder and having a first operating position and a second operating position, means operable by said piston for opening and closing said pressure space when said press piston is in said first and second positions respectively, an injection cylinder, an injection piston reciprocable in said injection cylinder and being movable in a direction for injecting molten metal into said pressure space and in an opposite direction to an initial starting position, a first source of fluid under pressure, means for selectively applying fluid under pressure from said first source to the press piston to actuate it between said two operating positions, an accumulator for accumulating fluid under high pressure therein, a second source of fluid, a pressure intensifier operable by said press piston for delivering fluid from the second source of fluid to the accumulator under high pressure in response to the reciprocation of the press piston, first conduit means providing communication between the second source of fluid and the pressure intensifier and second conduit means providing communication between the pressure intensifier and the high pressure accumulator, means for controllably applying fluid under pressure to the injection piston from the high pressure accumulator to reciprocate it in both of said directions once during closure of the pressure space bythe closure means operated by the press piston.

2. In a fluid operated die-casting machine having a pressure space for molding molten metal therein under pressure, in combination, a cylinder, at press piston in said press piston is in said first and second positions respectively, an injection cylinder, an injection piston reciprocable in said injection cylinder and being movable in a direction for injecting molten metal into said pressure space and in an opposite direction to an initial starting position, a first source of hydraulic fluid under pressure, means for selectively applying fluid under pressure from said first source to the press piston to actuate it between said two operating positions, an accumulator for accumulating hydraulic fluid under high pressure therein, a second source of hydraulic fluid, a pressure intensifier operable by said press piston for delivering fluid from the second source of fluid to the accumulator under high pressure in response to each reciprocation of the press piston, first conduit means providing one way communication between the second source of fluid and the pressure intensifier and second conduit means providing one-way communication between the pressure intensifier and the high pressure accumulator, means for controllably applying hydraulic fluid under pressure to the injection piston from the high pressure accumulator to reciprocate it in both of said directions once during closure of the pressure space by the closure means operated by the press piston.

3. In a fluid operated die-casting machine having a pressure space for molding molten metal therein under pressure, in combination, a cylinder, a press piston in said cylinder and having a first operating position and a second operating position, means operable by said piston for opening and closing said pressure space when said press piston is in said first and second positions respectively, an injection cylinder, an injection piston reciprocable in said injection cylinder and being movable in a direction for injecting molten metal into said pressure space and in an opposite direction to an initial starting position, a first source of fluid under pressure, means for selectively and controllably applying fluid under pressure from said first source to the press piston to actuate it between said two operating positions, an accumulator for accumulating hydraulic fluid under high pressure therein, a reservoir of hydraulic fluid, a pressure intensifier operable by said press piston for delivering hydraulic fluid from the reservoir to the accumulator under high pressure in response to the reciprocation of the press piston, first conduit means providing one-way communication between the hydraulic fluid reservoir and the pressure intensifier and second conduit means providing one-way communication between the pressure intensifier and the high pressure accumulator, means for controllably applying fluid under pressure to the injection piston from the high pressure accumulator to reciprocate it in both of said directions once during closure of the pressure space by the closure means operated by the press piston, and means to discharge the hydraulic fluid to the reservoir when the injection piston returns to its initial starting position.

4. In a fluid operated die-casting machine having a pressure space for molding molten metal therein under pressure, in combination, a cylinder, a press piston in said cylinder and having a first operating position and a second operating position, means operable by said piston for opening and closing said pressure space when said press piston is in said first and second positions respectively, an injection cylinder, an injection piston reciprocable in said injection cylinder and being movable in a direction for injecting molten metal into said pressure space and in an opposite direction to an initial starting position, a first source of fluid under pressure, means for selectively and controllably applying fluid under pressure from said first source to the press piston to actuate it between said two operating positions, an accumulator for accumulating hydraulic fluid under high pressure therein, 'a second source of fluid, a pressure intensifier comprising a pair of cylinders and pistons reciprocable therein and operable by said press piston for delivering fluid from the second source of fluid to the accumulator under high pressure in response to each reciprocation of the press piston, first conduit means providing one' way communication between the second source of fluid and the pressure intensifier and second conduit means providing one-way communication between the pressure intensifier and the high pressure accumulator, means including third conduit means for controllably applying fluid under pressure to the injection piston from the high pressure accumulator to reciprocate it in both of said directions as a cycle during closure of the pressure space by the closure means operated by the press piston.

5. In a fluid operated die-casting machine having a pressure space for molding molten metal therein under pressure, in combination, a cylinder, a press piston in said cylinder and having a first operating position and a second operating position, means operable by said piston for opening and closing said pressure space when said press piston is in said first and second positions respectively, an injection cylinder, an injection piston reciprocable in said injection cylinder and being movable in a direction for injecting molten metal into said pressure space and in an opposite direction to an initial starting position, a first source of hydraulic fluid under pressure, means for selectively and controllably applying fluid under pressure from said first source to the press piston to actuate it between said two operating positions, an accumulator for accumulating hydraulic fluid under a high pressure which is higher than the fluid pressure in said first source, a second source of fluid, a pressure intensifier operable by said press piston for delivering fluid from the second source of fluid to the accumulator under high pressure in response to the reciprocation of the press piston, first conduit means providing one-way communication between the second source of fluid and the pressure intensifier and second conduit means providing one-way communication between the pressure intensifier and the high pressure accumulator, means for controllably applying fluid under pressure to the injection piston firstly from the first source and subsequently from the high pressure accumulator to reciprocate it in both of said directions once during closure of the pressure space by the means operated by the press piston, said last mentioned means including control means for controllably applying the high fluid pressure from the accumulator to the injection piston only during the injection stroke of said injection piston and subsequent to the application of fluid under pressure from said first source.

6. A fluid operated die-casting machine according to claim 5, in which the first source of hydraulic fluid under pressure comprises another accumulator and in which said second source comprises a reservoir, and including means comprising a pump connected to pump hydraulic fluid from the reservoir to the other accumulator at an intermediate pressure which is lower in value than the high pressure in the high-pressure accumulator.

References Cited in the file of this patent UNITED STATES PATENTS 539,072 Mis May 14, 1895 962,906 March June 28, 1910 993,707 Murphy May 30, 1911 1,527,018 Smith Feb. 17, 1925 2,228,973 Polak Jan. 14, 1941 2,465,580 Ernst Mar. 29, 1949 2,634,468 Holder Apr. 14, 1953 FOREIGN PATENTS 597,111 Germany May 17, 1934 653,608 Germany Nov. 29, 1937

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