Cold chamber pressure casting machine

Claim 2

In a cold chamber pressure casting machine with a mold charge injector, a melting or heat-retaining crucible, and an injector supplying piston pump extending into the crucible, the piston pump having a pump chamber communicating with a feed opening which is beneath the level of the melt in the crucible: the improvement comprising, melt displacement means operatively associated with the melt in said crucible to maintain the level thereof substantially constant in the range of said piston pump; control means for controlling the effect of said displacement means on the melt level; and melt level feeler means positioned in said crucible in the range of the melt surrounding said piston pump for providing an indication of the melt level to said control means.

Claim 3

In a cold chamber pressure casting machine with a mold charge injector, a melting or heat-retaining crucible, and an injector supplying piston pump extending into the crucible, the piston pump having a pump chamber communicating with a feed opening which is beneath the level of the melt in the crucible: the improvement comprising, melt displacement means operatively associated with the melt in said crucible to maintain the level thereof substantially constant in the range of said piston pump; control means for controlling the effect of said displacement means on the melt level; and meLt level feeler means positioned in said crucible in the range of the melt surrounding said piston pump for providing an indication of the melt level to said control means; said displacement means comprising an immersion body mounted for lowering into said crucible and closed on all sides at least in the range of its contact with the melt.

Claim 4

In a cold chamber pressure casting machine with a mold charge injector, a melting or heat-retaining crucible, and an injector supplying piston pump extending into the crucible, the piston pump having a pump chamber communicating with a feed opening which is beneath the level of the melt in the crucible: the improvement comprising, melt displacement means operatively associated with the melt in said crucible to maintain the level thereof substantially constant in the range of said piston pump; control means for controlling the effect of said displacement means on the melt level; and meLt level feeler means positioned in said crucible in the range of the melt surrounding said piston pump for providing an indication of the melt level to said control means; said displacement means comprising an immersion body mounted for lowering into said crucible and closed on all sides at least in the range of its contact with the melt.

Claim 5

In a cold chamber pressure casting machine with a mold charge injector, a melting or heat-retaining crucible, and an injector supplying piston pump extending into the crucible, the piston pump having a pump chamber communicating with a feed opening which is beneath the level of the melt in the crucible: the improvement comprising, in combination, melt displacement means operatively associated with the melt in said crucible to maintain the level thereof substantially constant in the range of said piston pump; control means for controlling the effect of said displacement means on the melt level; melt level feeler means positioned in said crucible in the range of the melt surrounding said piston pump for providing an indication of the melt level to said control means; said displacement means comprising an insert mounted in said crucible and including a lateral wall and a closed upper end forming a pressure medium chamber having an open end below the maximum displacement level of the melt in a downward direction; and a pressure medium supply line connected to said insert and communicating with said pressure medium chamber; said control means also being for controlling flow of pressure medium through said supply line to maintain the melt level constant in the range of said piston pump.

Claim 6

In a cold chamber pressure casting machine with a mold charge injector, a melting or heat-retaining crucible, and an injector supplying piston pump extending into the crucible, the piston pump having a pump chamber communicating with a feed opening which is beneath the level of the melt in the crucible: the improvement comprising, in combination, melt displacement means operatively associated with the melt in said crucible to maintain the level thereof substantially constant in the range of said piston pump; control means for controlling the effect of said displacement means on the melt level; melt level feeler means positioned in said crucible in the range of the melt surrounding said piston pump for providing an indication of the melt level to said control means; said displacement means comprising an insert mounted in said crucible and including a lateral wall and a closed upper end forming a pressure medium chamber having an open end below the maximum displacement level of the melt in a downward direction; and a pressure medium supply line connected to said insert and communicating with said pressure medium chamber; said control means also being for controlling flow of pressure medium through said supply line to maintain the melt level constant in the range of said piston pump.

Claim 7

In a cold chamber pressure casting machine with a mold charge injector, a melting or heat-retaining crucible, and an injector supplying piston pump extending into the crucible, the piston pump having a pump chamber communicating with a feed opening which is beneath the level of the melt in the crucible: the improvement comprising, in combination, melt displacement means operatively associated with the melt in said crucible to maintain the level thereof substantially constant in the range of said piston pump; control means for controlling the effect of said displacement means on the melt level; melt level feeler means positioned in said crucible in the range of the melt surrounding said piston pump for providing an indication of the melt level to said control means; said displacement means comprising an insert mounted in said crucible and including a lateral wall and a closed upper end forming a pressure medium chamber having an open end below the maximum displacement level of the melt in a downward direction; a pressure medium supply line connected to said insert and communicating with said pressure medium chamber; said pressure medium supply line having, in the range of the maximum displacement level of the melt in a downward direction and in said insert, an opening; and a pressure followup valve connected to said pressure medium supply line and serving as said control means and said melt level feeler means; said pressure followup valve maintaining the pressure in said pressure medium chamber at a value corresponding to the hydraulic pressure of the melt between the nominal level of the melt in the crucible and said opening, said opening being at the lowest displacement level of the melt in said crucible.

Claim 8

In a cold chamber pressure casting machine with a mold charge injector, a melting or heat-retaining crucible, and an injector supplying piston pump extending into the crucible, the piston pump having a pump chamber communicating with a feed opening which is beneath the level of the melt in the crucible: the improvement comprising, in combination, melt displacement means operatively associated with the melt in said crucible to maintain the level thereof substantially constant in the range of said piston pump; control means for controlling the effect of said displacement means on the melt level; melt level feeler means positioned in said crucible in the range of the melt surrounding said piston pump for providing an indication of the melt level to said control means; said displacement means comprising an insert mounted in said crucible and including a lateral wall and a closed upper end forming a pressure medium chamber having an open end below the maximum displacement level of the melt in a downward direction; a pressure medium supply line connected to said insert and communicating with said pressure medium chamber; said pressure medium supply line having, in the range of the maximum displacement level of the melt in a downward direction and in said insert, an opening; and a pressure followup valve connected to said pressure medium supply line and serving as said control means and said melt level feeler means; said pressure followup valve maintaining the pressure in said pressure medium chamber at a value corresponding to the hydraulic pressure of the melt between the nominal level of the melt in the crucible and said opening, said opening being at the lowest displacement level of the melt in said crucible.

Claim 9

In a cold chamber pressure casting machine, the improvement claimed in claim 2, including a piston mounted for movement in a cylinder and connected to said immersion body; said control means supplying pressure fluid to one side of said piston to immerse said body in the melt.

Claim 10

In a cold chamber pressure casting machine, the improvement claimed in claim 5, including a spring biasing said piston in a direction to elevate said immersion body.

Claim 11

In a cold chamber pressure casting machine, the improvement claimed in claim 3, including a piston designed as a float within said insert.

Claim 12

In a cold chamber pressure casting machine, The improvement claimed in claim 3, in which the open end of said insert is closed except for a restricted port.

Claim 13

In a cold chamber pressure casting machine, the improvement claimed in claim 8, including a piston, designed as a float, in said chamber.

Claim 14

In a cold chamber pressure casting machine, the improvement claimed in claim 3, in which said control means comprises a pressure limiting device connected to said pressure medium chamber.

Claim 15

In a cold chamber pressure casting machine, the improvement claimed in claim 10, in which said insert is formed with a measuring chamber having an open end communicating with said pressure medium chamber adjacent the open end of the latter, and having its opposite end connected with and communicating with said pressure limiting device.

Claim 16

In a cold chamber pressure casting machine, the improvement claimed in claim 3, in which said pressure medium is a protective gas.

Claim 17

In a cold chamber pressure casting machine, the improvement claimed in claim 4, in which said pressure medium supply line is a passage formed in the lateral wall of said insert; said opening communicating with said pressure medium chamber.

Claim 18

In a cold chamber pressure casting machine, the improvement claimed in claim 4, in which said pressure followup valve is set to a fixed pressure value.

Claim 19

In a cold chamber pressure casting machine, the improvement claimed in claim 4, in which the upper wall of said insert is formed with a closable opening above the operating level of the melt.

Claim 20

In a cold chamber pressure casting machine, the improvement claimed in claim 15, including a float in said crucible in the range of the operating level of the melt and controlling said closable opening.