System for welding control

Claim 2

In a control system for timing a predetermined sequence of functions in an industrial process, electrical supply means, a voltage developing RC charging circuit connected to said potential supply means, a plurality of resistive circuits connected in parallel to said potential supply means and each being assigned to the timing of a respective funtion, a voltage comparator circuit having a plurality of inputs, a first one of which is connected to the capacitor charged terminal of said RC charging circuit, a common link between said resistive circuits and voltage comparator circuit, and means for seletively connectiNg each of said resistive circuits through said common link to the second input of said voltage comparator circuit, said voltage comparator circuit deriving an output control signal when the voltage of said RC charging circuit is of a predetermined relationship to the voltage applied by the connected resistive circuit.

Claim 3

Apparatus as claimed in claim 1, wherein each resistive circuit comprises a potentiometer adjustable to determine the voltage applied to the voltage comparator circuit.

Claim 4

Apparatus as claimed in claim 2, wherein each resistive circuit also comprises a resistance serially connected with the potentiometer, and the voltage applied to the voltage comparator circuit is derived from a tapping on the potentiometer.

Claim 5

Apparatus as claimed in claim 1, wherein said control system further includes diode means in circuit with said first input and said capacitor charge terminal.

Claim 6

Apparatus as claimed in claim 1, wherein said means for selectively connecting each of said plurality of resistive circuits includes transistor switch means connected to respective outputs of a shift register which is stepped from stage to stage by said output control signals.

Claim 7

Apparatus as claimed in claim 5, wherein said RC charging circuit includes a timing capacitor, wherein said transistor switch means includes a plurality of transistor switches a first one of which includes a resistor means connected to said capacitor charged terminal and operable to prevent charging of said timing capacitor by discharging voltage impressed on said capacitor through said resistor whenever the remainder of said transistor switches are in circuit with said resistive circuits to individually energize said circuits upon application of a positive current to the input terminal of said switches connected thereto.

Claim 8

Apparatus as claimed in claim 1, wherein said voltage comparator circuit derives an output control signal when the voltage of the RC charging circuit exceeds a voltage applied by the connected resistive circuit.

Claim 9

In a control system for generating a control signal to time automatically a predetermined sequence of functions in an industrial process, a voltage source, an RC circuit including a capacitor connected to receive an electrical charge from said voltage source, a plurality of resistive circuits connected in parallel across said voltage source and each associated with the timing of an individual function in the sequence and providing an output voltage indicative of a parameter of the associated function, a common link between the resistive circuits and the RC circuit, means for connecting in turn to the common link the output of selected ones of said resistive circuits, and voltage comparator means in the common link to compare the voltage of the charge in the RC circuit with the output voltage of the connected resistive circuit, said voltage comparator means providing said output control signal when the former voltage is of a predetermined relationship to the latter voltage.

Claim 10

In a control system for generating a control signal to time automatically a predetermined sequence of functions in an industrial process, a voltage source, an RC circuit including a capacitor connected to receive an electrical charge from said voltage source, a plurality of resistive circuits connected in parallel across said voltage source and each associated with the timing of an individual function in the sequence and providing an output voltage indicative of a parameter of the associated function, a common link between the resistive circuits and the RC circuit, means for connecting in turn to the common link the output of selected ones of said resistive circuits, and voltage comparator means in the common link to compare the voltage of the charge in the RC circuit with the output voltage of the connected resistive circuit, said voltage comparator means providing said output control signal when the former voltage is of a predetermined relationship to the latter voltage.

Claim 11

Apparatus as claimed in claim 8, wherein the voltage comparator means comprises a diode, a pulse generating transformer, and an output transformer whose primary winding is serially connected with the diode and the transformer, whereby pulses from the pulse generating transformer are normally blocked by the diode from passing through the output transformer util the voltage of the charge in the RC circuit is of a predetermined relationship to the output voltage of the connected resistive circuit.

Claim 12

Apparatus as claimed in claim 8, wherein a second electrical RC charging circuit is connected in parallel with the voltage source and its capacitor is connected also to receive the output voltage from the connected resistive circuit, the time constant of the second RC charging circuit being less than that of the first mentioned RC circuit.

Claim 13

Apparatus as claimed in claim 8, wherein the means of selectively connecting ones of the resistive circuits are switches connecteD to respective outputs of a shift register stepped from stage to stage by said output control signals.