Safety circuit for electric steering system

Claim 2

A control circuit for a marine propulsion installation including a marine propulsion device having a steering unit swingable about a steering axis under normal operating conditions and a steering wheel remote from the steering unit, said control comprising a first potentiometer adapted to be connected to a source of electrical current and having a first wiper connected to the steering wheel and movable in response to steering wheel movement to afford variation in the potential at said first wiper in accordance with steering wheel setting, a second potentiometer adapted to be connected to a source of electrical current in common with said first potentiometer and including a second wiper connected to the swingable steering unit and movable in response to steering unit movement to afford variation in the potential at said second wiper in accordance with the position of the swingable steering unit, means adapted to be connected to a source of electrical current and to said wipers for generating a first output for swinging said steering unit in response to operation of said steering wheel, and means for informing an operator of the presence of a difference in potential at said wipers above a predetermined value including switch means for generating, when the difference in potential at said wipers exceeds the predetermined value, a second output for actuating said operator informing means, said switch means comprising a relay switch having a coil, a first transistor having a collector adapted to be connected to a source of electrical current, a base connected to said first potentiometer wiper, and an emitter connected to one end of said coil, a second transistor adapted to be connected to a source of electrical current in common with said collector of said first transistor, a base connected to said second potentiometer wiper, and an emitter connected to the other end of said coil.

Claim 3

A control circuit in accordance with cLaim 1 wherein said emitters are also connected to ground.

Claim 4

A control circuit in accordance with claim 1 wherein said relay switch includes a first terminal adapted to be connected to a source of electrical current, a second terminal adapted to be connected to an electrical device operable to alert the operator, a contact member moveable between a first position connecting said first and second terminals and a second position disconnecting said first and second terminals, means biasing said contact member to one of said positions, and an armature extending through said coil, connected to said contact member, and operable to displace said contact member to the other of said positions in response to energizing of said coil above a predetermined value.

Claim 5

A marine propulsion installation including an engine with an ignition system, a steering unit swingable about a generally upright axis under normal operating conditions, a steering wheel remote from the steering unit, and a control comprising a first potentiometer connected to a source of electrical current and having a first wiper connected to said steering wheel to afford variation in the potential at said first wiper in accordance with the setting of said steering wheel, a second potentiometer connected to a source of electrical current in common with said first potentiometer and including a second wiper connected to said swingable steering unit to afford variation in the potential at said second wiper in accordance with the position of said swingable steering unit, and switch means connected to a source of electrical current, to said wipers, and to said ignition system, and including means for generating an output operable, when the difference in potential at said wipers exceeds a predetermined value, for preventing operation of said ignition system.

Claim 6

A marine propulsion installation including an engine with an ignition system, a steering unit swingable about a generally upright axis under normal operating conditions, a steering wheel remote from the steering unit, and a control comprising a first potentiometer connected to a source of electrical current and having a first wiper connected to said steering wheel to afford variation in the potential at said first wiper in accordance with the setting of said steering wheel, a second potentiometer connected to a source of electrical current in common with said first potentiometer and including a second wiper connected to said swingable steering unit to afford variation in the potential at said second wiper in accordance with the position of said swingable steering unit, and switch means connected to a source of electrical current, to said wipers, and to said ignition system, and including means for generating an output operable, when the difference in potential at said wipers exceeds a predetermined value, for preventing operation of said ignition system.

Claim 7

A control circuit in accordance with claim 4 wherein said means for preventing engine ignition includes electrically operated switch means controlling continued engine ignition operation, first transistorized switch means adapted to be connected to a source of electrical current and to said first potentiometer wiper and to said electrically operated switch means, and second transistorized switch means adapted to be connected to a source of electrical current in common with said first transistorized switch means and to said second potentiometer wiper and to said electrically operated switch means.

Claim 8

A control circuit in accordance with claim 5 wherein said electrically operated switch means includes a relay coil, wherein said first transistorized switch means includes a first transistor having a collector adapted to be connected to the current source common to said first and second transistorized switch means, an emitter connected to one end of said relay coil, and a base connected to said first potentiometer wiper, and wherein said second transistorized switch means includes a second transistor having a collector adapted to be connected to the current source common to said first and second transistorized switch means, an emitter connected to the other end of said relay coil, and a base connected to said second potentiometer wiper.

Claim 9

A control circuit in accordance with claim 5 wherein said electrically operated switch means includes a first contact connected to one of said engine ignition system and a source of electrical current, a second contact connected to the other of said engine ignition system and the source of electrical current, said second contact being movable relative to a position in engagement with said first contact, a coil energized in response to operation of said first and second transistorized switch means, an armature associated with said coil and mechanically connected to said second contact, and means biasing said movable second contact away from said position in engagement with said first contact.

Claim 10

A steering and ignition control circuit for a marine propulsion device having an internal combustion engine with an ignition system and a steering unit swingable about a steering axis under normal operating conditions and adapted to be controlled by a remotely located steering wheel, said circuit comprising a first switch adapted to be connected to a source of electrical energy and movable between open and closed conditions, an engine ignition switch controlling electrical connection between the ignition system and a source of electrical energy, said ignition switch being biased to normally prevent engine ignition system operation, a selector switch connected to said first switch and including a movable contact selectively connectable with an electric steering contact and with a by-pass contact electrically connected to said engine ignition switch so that when said first switch is closed and said selector switch is positioned to connect said movable contact to said by-pass contact, said engine ignition switch is actuated to permit engine ignition system operation, a safety switch electrically connected between said engine ignition switch and said electric steering contact, said safety switch being biased to normally electrically connect said electric steering contact to said engine ignition switch and thereby to actuate said engine ignition switch to permit engine ignition operation when said first switch is closed and said selector switch is positioned with said movable contact is in engagement with said electric steering contact, and a safety circuit portion including means for actuating said safety switch in the absence of proper coordination between the steering wheel and the steering unit to thereby electrically disconnect said ignition switch from said electric steering contact and thereby to prevent engine ignition system operation when said first switch is closed and said movable contact of said selector switch is engaged with said electric steering contact.

Claim 11

A steering and ignition control circuit for a marine propulsion device having an internal combustion engine with an ignition system and a steering unit swingable about a steering axis under normal operating conditions and adapted to be controlled by a remotely located steering wheel, said circuit comprising a first switch adapted to be connected to a source of electrical energy and movable between open and closed conditions, an engine ignition switch controlling electrical connection between the ignition system and a source of electrical energy, said ignition switch being biased to normally prevent engine ignition system operation, a selector switch connected to said first switch and including a movable contact selectively connectable with an electric steering contact and with a by-pass contact electrically connected to said engine ignition switch so that when said first switch is closed and said selector switch is positioned to connect said movable contact to said by-pass contact, said engine ignition switch is actuated to permit engine ignition system operation, a safety switch electrically connected between said engine ignition switch and said electric steering contact, said safety switch being biased to normally electrically connect said electric steering contact to said engine ignition switch and thereby to actuate said engine ignition switch to permit engine ignition operation when said first switch is closed and said selector switch is positioned with said movable contact is in engagement with said electric steering contact, and a safety circuit portion including means for actuating said safety switch in the absence of proper coordination between the steering wheel and the steering unit to thereby electrically disconnect said ignition switch from said electric steering contact and thereby to prevent engine ignition system operation when said first switch is closed and said movable contact of said selector switch is engaged with said electric steering contact.

Claim 12

A steering and ignition control circuit in accordance with claim 8 wherein said means for actuating said safety switch includes a first position sensing potentiometer adapted to be connected to a source of electrical current and having a first wiper connected to the steering wheel to afford variation in the potential at said first wiper in accordance with steering wheel setting, a second position sensing potentiometer adapted to be connected to a source of electrical current in common with said first potentiometer and including a second wiper connected to the swingable steering unit to afford variation in the potential at said second wiper in accordance with the position of the swingable steering unit, and switch means adapted to be connected to a source of electrical current and to said wipers and to said safety switch for actuating said safety switch when the difference in potential at said wipers exceeds a predetermined value.

Claim 13

A steering and ignition control circuit in accordance with claim 9 and further including means adapted to be connected to a source of electrical current and to said wipers and selectively operable for causing swinging of the steering unit in response to movement of the steering wheel.