Method and apparatus for controlling low pressure die casting

Claim 2

In a casting method, the steps of: introducing a molten casting material into a die cavity through an inlet passage by applying gaseous pressure thereto; sensing the temperature of the casting material by measuring the temperature of the casting material at at least one location in said inlet passage and at at least one location in said die cavity; generating a signal in response to the sensing of predetermined temperature conditions in said casting material, said predetermined temperature conditions comprising the situation when each of the measured temperatures has fallen below a predetermined level; and using the generated signal to terminate the application of said gaseous pressure to the molten casting material.

Claim 3

In a casting method, the steps of: introducing a molten casting material into a die cavity through an inlet passage by applying gaseous pressure thereto; sensing the temperature of the casting material by measuring the temperature of the casting material at at least one location in said inlet passage and at at least one location in said die cavity, said temperature being measured at at least three locations; generating a signal in response to the sensing of predetermined temperaTure conditions in said casting material, said predetermined temperature conditions comprising the situation when at least two of the measured temperatures have fallen below a predetermined level; and using the generated signal to terminate the application of said gaseous pressure to the molten casting material.

Claim 4

In a casting method, the steps of: introducing a molten casting material into a die cavity through an inlet passage by applying gaseous pressure thereto; sensing the temperature of the casting material by measuring the temperature of the casting material at at least one location in said inlet passage and at at least one location in said die cavity, said temperature being measured at at least three locations; generating a signal in response to the sensing of predetermined temperaTure conditions in said casting material, said predetermined temperature conditions comprising the situation when at least two of the measured temperatures have fallen below a predetermined level; and using the generated signal to terminate the application of said gaseous pressure to the molten casting material.

Claim 5

In a casting method, the steps of: introducing a molten casting material into a die cavity through an inlet passage by applying gaseous pressure thereto; sensing the temperature of the casting material by measuring the temperature of the casting material at at least one location in said inlet passage and at at least one location in said die cavity, said temperature being measured at at least three locations; generating a signal in response to the sensing of predetermined temperature conditions in said casting material, said predetermined temperature conditions comprising the situation when the average of at least two of the measured temperatures has fallen below a predetermined level; and using the generated signal to terminate the application of said gaseous pressure to the molten casting material.

Claim 6

In a casting method, the steps of: introducing a molten casting material into a die cavity through an inlet passage by applying gaseous pressure thereto; sensing the temperature of the casting material by measuring the temperature of the casting material at at least one location in said inlet passage and at at least one location in said die cavity, said temperature being measured at at least three locations; generating a signal in response to the sensing of predetermined temperature conditions in said casting material, said predetermined temperature conditions comprising the situation when the average of at least two of the measured temperatures has fallen below a predetermined level; and using the generated signal to terminate the application of said gaseous pressure to the molten casting material.

Claim 7

A method as set forth in claim 1 wherein said predetermined temperature level for said inlet passage is different than said predetermined temperature level for said die cavity.

Claim 8

In a casting machine, die means defining a die cavity and an inlet passage to the cavity; gaseous pressure injection means for applying gaseous pressure to a supply of molten casting material and forcing the same into said cavity through said passage; temperature sensing means for sensing the temperature of the casting material, said temperature sensing means including sensor means having a temperature actuated electrical contact which is closed when the temperature of the sensor is below a predetermined value; signal generating means for generating a signal in response to the sensing of predetermined temperature conditions in the casting material by the temperature sensing means; and means coupled to said signal generating means and said injection means for terminating the application of said pressure to the molten casting material when said signal is generated, said pressure application terminating means including an electrical circuit comprising a primary relay having a normally open contact, a normally closed contact and a coil connected across the supply through said temperature actuated contact, and a secondary relay having a pair of normally open contacts and a coil connected across the supply through a contact which closes when the pressure injection means are actuated, said latter contact being in series with the normally closed contact of the primary relay which is shunted by one of the normally open contacts of the secondary relay, the switching off of the pressure injection means being under the control of the normally open contact of the primary relay and the other normally open contact of the secondary relay, said last mentioned contacts being connected in series, whereby said pressure application terminating means are arranged to operate only when the temperature has risen above a predetermined level and has thereafter fallen below such level.

Claim 9

In a casting machine, die means defining a die cavity and an inlet passage to the cavity; gaseous pressure injection means for applying gaseous pressure to a supply of molten casting material and forcing the same into said cavity through said passage; temperature sensing means for sensing the temperature of the casting material, said temperature sensing means including sensor means having a temperature actuated electrical contact which is closed when the temperature of the sensor is below a predetermined value; signal generating means for generating a signal in response to the sensing of predetermined temperature conditions in the casting material by the temperature sensing means; and means coupled to said signal generating means and said injection means for terminating the application of said pressure to the molten casting material when said signal is generated, said pressure application terminating means including an electrical circuit comprising a primary relay having a normally open contact, a normally closed contact and a coil connected across the supply through said temperature actuated contact, and a secondary relay having a pair of normally open contacts and a coil connected across the supply through a contact which closes when the pressure injection means are actuated, said latter contact being in series with the normally closed contact of the primary relay which is shunted by one of the normally open contacts of the secondary relay, the switching off of the pressure injection means being under the control of the normally open contact of the primary relay and the other normally open contact of the secondary relay, said last mentioned contacts being connected in series, whereby said pressure application terminating means are arranged to operate only when the temperature has risen above a predetermined level and has thereafter fallen below such level.

Claim 10

In a casting machine, die means defining a die cavity and an inlet passage to the cavity; gaseous pressure injection means for applying gaseous pressure to a supply of molten casting material and forcing the same into said cavity through said passage; temperature sensing means for sensing the temperature of the casting material including a temperature sensor located in the die cavity; first signal generating means for generating a first signal in response to the sensing of first predetermined temperature conditions in the casting material by the temperature sensing means; means coupled to said first signal generating means and said injection means for terminating the application of said pressure to the molten casting material when said first signaL is generated; second signal generating means for generating a second signal in response to the sensing of second predetermined temperature conditions in the casting material by said temperature sensor independently of the sensing of said first predetermined temperature conditions; and control means coupled to said second signal generating means and said die means for initiating a die opening sequence when said second signal is generated.

Claim 11

In a casting machine, die means defining a die cavity and an inlet passage to the cavity; gaseous pressure injection means for applying gaseous pressure to a supply of molten casting material and forcing the same into said cavity through said passage; temperature sensing means for sensing the temperature of the casting material including a temperature sensor located in the die cavity; first signal generating means for generating a first signal in response to the sensing of first predetermined temperature conditions in the casting material by the temperature sensing means; means coupled to said first signal generating means and said injection means for terminating the application of said pressure to the molten casting material when said first signaL is generated; second signal generating means for generating a second signal in response to the sensing of second predetermined temperature conditions in the casting material by said temperature sensor independently of the sensing of said first predetermined temperature conditions; and control means coupled to said second signal generating means and said die means for initiating a die opening sequence when said second signal is generated.

Claim 12

Apparatus as set forth in claim 6 wherein said sensor includes a temperature actuated electrical contact which is closed when the temperature of the sensor is below a predetermined value, said control means including an electrical circuit comprising a primary relay having a normally open contact a normally closed contact and a coil connected across a supply through said temperature actuated contact, and a secondary relay having a pair of normally open contacts and coil connected across the supply through a contact which closes when the die is closed, said latter contact being connected in series with the normally closed contact of the primary relay which is shunted by one of the normally open contacts of the secondary relay, the opening of the dies being under the control of the normally open contact of the primary relay and the other normally open contact of the secondary relay, said last mentioned contacts being connected in series.