Blasting machine with overvoltage and undervoltage protection for the energy storage capacitor

Claim 2

A blasting machine comprising: means for storing electrical energy; means for supplying electrical energy to said energy storage means, said means for supplying electrical energy comprising: a source of electrical energy; a transformer having a primary winding connected to said source and a secondary winding; a first diode means and said electrical storage means connected together in series across said secondary winding to store energy generated by the current flowing through said primary winding; a solid state switch oscillator connected to said source and said transformer to periodically interrupt current flow from said source through said primary winding, said oscillator including: a first transistor having collector and emitter terminals in series with said primary winding, said transistor having alternate conductive and nonconductive intervals to periodically interrupt the current flowing from said primary winding; a first voltage divider network connected across said first transistor and said primary winding, said first voltage divider network including second diode means connected to the junction between said primary winding and said first transistor to direct current from said winding in a predetermined manner; and a second voltage divider network connected across said source of electrical energy, said second voltage divider network including a second transistor having alternate conductive and nonconductive intervals to respectively control the conductive and nonconductive intervals of said first transistor whereby the flow of current from said source to said primary winding is periodically interrupted causing current to flow in an oscillatory manner through said primary winding. means for producing a plurality of electrical pulses when said energy storage means has reached a first predetermined energy level; switching means for receiving said pulses, said switching means operable to permit the discharge of said energy storage means only during the presence of said pulses, whereby said energy storage means cannot be discharged below said predetermined energy level; and means for preventing said means for storing electrical energy from exceeding a second predetermined energy level which is above said first predetermined energy level whereby said energy storage means is prevented from reaching energy levels above said second predetermined energy level.

Claim 3

A blasting machine as described in claim 1 wherein said means for preventing said means for storing electrical energy from exceeding a second predetermined voltage level includes an electrical circuit which comprises: a gaseous conductor connected in series to a resistor and a capacitor, said capacitor connected in parallel with a second resistor, said electrical circuit connected across said means for storing electrical energy whereby when said means for storing electrical enerGy reaches said second predetermined energy level, said gaseous conductor conducts to prevent said means for storing electrical energy from exceeding said second predetermined energy level.

Claim 4

The blasting machine as recited in claim 1 wherein the first voltage divider network of said means for supplying electrical energy to said energy storage means comprises: a diode having a first terminal connected to the junction between said primary winding and said source of electrical energy and a second terminal connected to the base of said second transistor; a first resistor in series with the second terminal of said diode; a second resistor in series with said first resistor, and a third resistor in series with said second resistor and having one terminal connected to the junction between said first transistor and said source of electrical energy.

Claim 5

A blasting machine as described in claim 3 wherein said means for preventing said means for storing electrical energy from exceeding a second predetermined voltage level includes an electrical circuit which comprises: a gaseous conductor connected in series to a resistor and a capacitor, said capacitor connected in parallel with a second resistor, said electrical circuit connected across said means for storing electrical energy whereby when said means for storing electrical energy reaches said second predetermined energy level, said gaseous conductor conducts to prevent said means for storing electrical energy from exceeding said second predetermined energy level.

Claim 6

A blasting machine which comprises: means for storing electrical energy; means for supplying electrical energy to said energy storage means, said means for supplying electrical energy comprising: a source of electrical energy; a transformer having a primary winding connected to said source and a secondary winding; a first diode means and said electrical energy storage means connected together in series across said secondary winding to store energy generated by the current flowing through said primary winding; a solid state switch oscillator connected to said source and said transformer to periodically interrupt current flow from said source through said primary winding, said oscillator including: a first transistor having collector and emitter terminals in series with said primary winding, said transistor having alternate conductive and nonconductive intervals to periodically interrupt the current flowing from said primary winding; a first voltage divider network connected across said first transistor and said primary winding, said first voltage divider network including second diode means connected to the junction between said primary winding and said first transistor to direct current from said winding unidirectionally to said first voltage divider network; and a second voltage divider network connected across said source of electrical energy, said second voltage divider network including a second transistor having alternate conductive and nonconductive intervals to respectively control the conductive and nonconductive intervals of said first transistor whereby the flow of current from said source to said primary winding is periodically interrupted causing current to flow in an oscillatory manner through said primary winding; means for producing a plurality of electrical pulses when said energy storage means has reached a first predetermined energy level, said means for producing electrical pulses including a second normally nonconductive gaseous conductor which is rendered conductive when a predetermined voltage is applied thereto and a resistor capacitor circuit in series with said second gaseous conductor so that when said second gaseous conductor is rendered conductive, said capacitor lowers the voltage applied to said second gaseous conductor below said predetermined value and said second gaseous conductor is rendered nonconductive; switching means for receiving said pulses, said switchinG means operable to permit the discharge of said energy storage means only during the presence of said pulses, whereby said energy storage means cannot be discharged below said predetermined energy level, said switching means including a first normally nonconductive gaseous conductor in circuit relationship with said pulse means, said first gaseous conductor being rendered conductive upon receiving said pulses, whereby when pulses from said pulse means are transmitted to said first gaseous conductor, said first gaseous conductor is rendered conductive to permit said storage means to discharge and a switch connected between said first gaseous and said pulse means, said switch operable in the ON position to permit passage of said pulses to said first gaseous conductor, whereby the energy storage means is discharged only when said switch is in the ON position and when said pulse means is producing pulses; and means for preventing said means for storing electrical energy for exceeding a second predetermined energy level which is above said first predetermined energy level whereby said energy storage means is prevented from reaching energy levels above said second predetermined energy level.

Claim 7

A blasting machine which comprises: means for storing electrical energy; means for supplying electrical energy to said energy storage means, said means for supplying electrical energy comprising: a source of electrical energy; a transformer having a primary winding connected to said source and a secondary winding; a first diode means and said electrical energy storage means connected together in series across said secondary winding to store energy generated by the current flowing through said primary winding; a solid state switch oscillator connected to said source and said transformer to periodically interrupt current flow from said source through said primary winding, said oscillator including: a first transistor having collector and emitter terminals in series with said primary winding, said transistor having alternate conductive and nonconductive intervals to periodically interrupt the current flowing from said primary winding; a first voltage divider network connected across said first transistor and said primary winding, said first voltage divider network including second diode means connected to the junction between said primary winding and said first transistor to direct current from said winding unidirectionally to said first voltage divider network; and a second voltage divider network connected across said source of electrical energy, said second voltage divider network including a second transistor having alternate conductive and nonconductive intervals to respectively control the conductive and nonconductive intervals of said first transistor whereby the flow of current from said source to said primary winding is periodically interrupted causing current to flow in an oscillatory manner through said primary winding; means for producing a plurality of electrical pulses when said energy storage means has reached a first predetermined energy level, said means for producing electrical pulses including a second normally nonconductive gaseous conductor which is rendered conductive when a predetermined voltage is applied thereto and a resistor capacitor circuit in series with said second gaseous conductor so that when said second gaseous conductor is rendered conductive, said capacitor lowers the voltage applied to said second gaseous conductor below said predetermined value and said second gaseous conductor is rendered nonconductive; switching means for receiving said pulses, said switchinG means operable to permit the discharge of said energy storage means only during the presence of said pulses, whereby said energy storage means cannot be discharged below said predetermined energy level, said switching means including a first normally nonconductive gaseous conductor in circuit relationship with said pulse means, said first gaseous conductor being rendered conductive upon receiving said pulses, whereby when pulses from said pulse means are transmitted to said first gaseous conductor, said first gaseous conductor is rendered conductive to permit said storage means to discharge and a switch connected between said first gaseous and said pulse means, said switch operable in the ON position to permit passage of said pulses to said first gaseous conductor, whereby the energy storage means is discharged only when said switch is in the ON position and when said pulse means is producing pulses; and means for preventing said means for storing electrical energy for exceeding a second predetermined energy level which is above said first predetermined energy level whereby said energy storage means is prevented from reaching energy levels above said second predetermined energy level.

Claim 8

A blasting machine as described in claim 5 wherein said means for preventing said means for storing electrical energy from exceeding a second predetermined voltage level includes an electrical circuit which comprises: a third gaseous conductor connected in series to a resistor and a capacitor, said capacitor connected in parallel with a second resistor, said electrical circuit connected across said means for storing electrical energy whereby when said means for storing electrical energy reaches said predetermined energy level, said third gaseous conductor conducts to prevent said means for storing electrical energy from exceeding said second predetermined energy level.

Claim 9

A blasting machine as recited in claim 5 wherein said first voltage divider network of said means for supplying electrical energy to said energy storage means comprises: a diode having a first terminal connected to the junction between said primary winding and said source of electrical energy and a second terminal connected to the base of said second transistor; a first resistor in series with the second terminal of said diode; a second resistor in series with said first resistor; and a third resistor in series with said second resistor and having one terminal connected to the junction between said first transistor and said source of electrical energy.

Claim 10

A blasting machine as described in claim 7 wherein said means for preventing said means for storing electrical energy from exceeding a second predetermined voltage level includes an electrical circuit which comprises: a third gaseous conductor connected in series to a resistor and a capacitor, said capacitor connected in parallel with a second resistor, said electrical circuit connected across said means for storing electrical energy whereby when said means for storing electrical energy reaches said predetermined energy level, said third gaseous conductor conducts to prevent said means for storing electrical energy from exceeding said second predetermined energy level.