Solid state electronic timer

Claim 2

A control circuit comprising a a pair of terminals adapted to be connected across a source of potential, a silicon controlled rectifier having an anode, a cathode and a gate electrode, said silicon controlled rectifier being adapted to conduct when the potential applied to said gate electrode reaches a predetermined value, lead means for connecting the anode-cathode path of said silicon controlled rectifier between said pair of terminals, a relay operable between an energized and a deenergized state for controlling the operation of an associated device, circuit means for connecting said relay with said silicon controlled rectifier for moving said relay from one state to the other in response to the conduction of said silicon controlled rectifier, biasing means operably connected to and establishing biasing potentials for said silicon controlled rectifier, time delay means for applying said predetermined value of potential to said gate electrode a preselected interval of time after said time delay means is energized, said time delay means comprising resistor means connected in series with a capacitor between said anode and cathode electrodes, means for directly connecting said gate electrode to the junction of said resistor means and said capacitor, said relay being connected in parallel with the anode-cathode path of said silicon controlled rectifier, said relay includes normally open contacts connected between said silicon controlled rectifier and one of said pair of terminals, said contacts being opeRable to close in response to the energization of said relay, and a switch, a resistor having one end connected to said junction and the other end connected to said one terminal through said switch, said capacitor having one end connected to said one terminal through said switch, whereby the opening of said switch causes said capacitor to charge to said predetermined value of potential in said preselected interval of time.

Claim 3

A control circuit comprising a pair of terminals adapted to be connected across a source of potential, a silicon controlled rectifier having an anode, a cathode and a gate electrode, said silicon controlled rectifier being adapted to conduct when the potential applied to said gate electrode reaches a predetermined value, lead means for connecting the anode-cathode path of said silicon controlled rectifier between said pair of terminals, a relay operable between an energized and a deenergized state for controlling the operation of an associated device, circuit means for connecting said relay with said silicon controlled rectifier for moving said relay from one state to the other in response to the conduction of said silicon controlled rectifier, biasing means operably connected to and establishing biasing potentials for said silicon controlled rectifier, time delay means for applying said predetermined value of potential to said gate electrode a preselected interval of time after said time delay mean is energized, said time delay means comprising resistor means connected in series with a capacitor between said anode and cathode electrodes, means for directly connecting said gate electrode to the junction of said resistor means and said capacitor, said relay being connected in parallel with the anode-cathode path of said silicon controlled rectifier, a switch connected between one of said terminals and said capacitor, said relay including a movable armature engaging a first contact and adapted to engage a second contact in response to the energization of said relay, said armature being connected to said one terminal through said switch, means connecting said second contact with said one terminal, a resistor, and means connecting said resistor between said junction and said first contact, whereby the closure of said switch causes the energization of said relay to move said armature from said first to said second contact to initiate charging of said capacitor.

Claim 4

A control circuit comprising a pair of terminals adapted to be connected across a source of potential, a silicon controlled rectifier having an anode, a cathode and a gate electrode, said silicon controlled rectifier being adapted to conduct when the potential applied to said gate electrode reaches a predetermined value, lead means for connecting the anode-cathode path of said silicon controlled rectifier between said pair of terminals, a relay operable between an energized and a deenergized state for controlling the operation of an associated device, circuit means for connecting said relay with said silicon controlled rectifier for moving said relay from one state to the other in response to the conduction of said silicon controlled rectifier, biasing means operably connected to and establishing biasing potentials for said silicon controlled rectifier, time delay means for applying said predetermined value of potential to said gate electrode a preselected interval of time after said time delay mean is energized, said time delay means comprising resistor means connected in series with a capacitor between said anode and cathode electrodes, means for directly connecting said gate electrode to the junction of said resistor means and said capacitor, said relay being connected in parallel with the anode-cathode path of said silicon controlled rectifier, a switch connected between one of said terminals and said capacitor, said relay including a movable armature engaging a first contact and adapted to engage a second contact in response to the energization of said relay, said armature being connected to said one terminal through said switch, means connecting said second contact with said one terminal, a resistor, and means connecting said resistor between said junction and said first contact, whereby the closure of said switch causes the energization of said relay to move said armature from said first to said second contact to initiate charging of said capacitor.