1. A steering system for a marine vessel that includes at least two outboard motors, each of the least two outboard motors including a motor and a propeller rotated by the motor, the marine vessel steering system comprising:
a steering member;
at least two turning mechanisms respectively arranged to turn the at least two outboard motors individually and each of the at least two turning mechanisms including an electric motor driven in accordance with an operation of the steering member; and
an electric motor control unit arranged and programmed to control the at least two electric motors so that during straight traveling of the marine vessel a toe angle between the at least two outboard motors is equal to a straight traveling toe angle set in advance; wherein
the straight traveling toe angle is set to an angle such that electric currents flowing through the at least two electric motors during the straight traveling of the marine vessel are minimized.
2. The marine vessel steering system according to claim 1, further comprising:
a steering angle detecting unit arranged to detect a steering angle of the steering member;
a plurality of actual turning angle detecting units arranged to detect actual turning angles of the at least two outboard motors; and
a basic target turning angle computing unit arranged and programmed to compute a basic target turning angle based on the steering angle detected by the steering angle detecting unit; wherein
the electric motor control unit includes:
a traveling state determining unit arranged to determine whether or not the traveling state of the marine vessel is the straight traveling state;
a target turning angle computing unit arranged and programmed to compute target turning angles of the at least two outboard motors based on the determination result of the traveling state determining unit and the basic target turning angle computed by the basic target turning angle computing unit; and
a feedback control unit arranged and programmed to control the at least two electric motors so that the actual turning angles of the at least two outboard motors detected by the actual turning angle detecting unit approach the target turning angles of the at least two outboard motors computed by the target turning angle computing unit; wherein
when the traveling state determining unit determines that the traveling state is the straight traveling state, the target turning angle computing unit computes, based on the basic target turning angle computed by the basic target turning angle computing unit and the straight traveling toe angle, the target turning angles of the at least two outboard motors such that the toe angle between the at least two outboard motors is equal to the straight traveling toe angle; and
when the traveling state determining unit determines that the traveling state is not the straight traveling state, the target turning angle computing unit computes the target turning angles of the at least two outboard motors based on the basic target turning angle computed by the basic target turning angle computing unit.
3. The marine vessel steering system according to claim 2, wherein the traveling state determining unit is arranged to determine whether or not the traveling state is the straight traveling state based on whether or not the basic target turning angle computed by the basic target turning angle computing unit is within a predetermined angular range set in advance.
4. The marine vessel steering system according to claim 1, further comprising:
at least two current detecting units arranged to detect the electric currents of the at least two electric motors;
a current value outputting unit arranged to display or externally output the motor current values detected by the at least two current detecting units; and
a toe angle settingchanging unit arranged to set or change the straight traveling toe angle.
5. The marine vessel steering system according to claim 2, further comprising:
at least two current detecting units arranged to detect the electric currents of the at least two electric motors;
a current value outputting unit arranged to display or externally output the motor current values detected by the at least two current detecting units; and
a toe angle settingchanging unit arranged to set or change the straight traveling toe angle.
6. The marine vessel steering system according to claim 3, further comprising:
at least two current detecting units arranged to detect the electric currents of the at least two electric motors;
a current value outputting unit arranged to display or externally output the motor current values detected by the at least two current detecting units; and
a toe angle settingchanging unit arranged to set or change the straight traveling toe angle.
7. The marine vessel steering system according to claim 1, wherein the angle at which the electric currents flowing through the at least two electric motors are minimized, is a toe-in angle in which front ends of the at least two outboard motors are directed inward.
8. The marine vessel steering system according to claim 2, wherein the angle at which the electric currents flowing through the at least two electric motors are minimized, is a toe-in angle in which front ends of the at least two outboard motors are directed inward.
9. The marine vessel steering system according to claim 3, wherein the angle at which the electric currents flowing through the at least two electric motors are minimized, is a toe-in angle in which front ends of the at least two outboard motors are directed inward.
10. The marine vessel steering system according to claim 4, wherein the angle at which the electric currents flowing through the at least two electric motors are minimized, is a toe-in angle in which front ends of the at least two outboard motors are directed inward.
11. The marine vessel steering system according to claim 5, wherein the angle at which the electric currents flowing through the at least two electric motors are minimized, is a toe-in angle in which front ends of the at least two outboard motors are directed inward.
12. The marine vessel steering system according to claim 6, wherein the angle at which the electric currents flowing through the at least two electric motors are minimized, is a toe-in angle in which front ends of the at least two outboard motors are directed inward.
13. The marine vessel steering system according to claim 7, wherein a cross-section, perpendicular to a frontrear direction of the marine vessel, of a hull bottom at a rear portion of a hull of the marine vessel has a V-shape.
14. The marine vessel steering system according to claim 8, wherein a cross-section, perpendicular to a frontrear direction of the marine vessel, of a hull bottom at a rear portion of a hull of the marine vessel has a V-shape.
15. The marine vessel steering system according to claim 9, wherein a cross-section, perpendicular to a frontrear direction of the marine vessel, of a hull bottom at a rear portion of a hull of the marine vessel has a V-shape.
16. The marine vessel steering system according to claim 10, wherein a cross-section, perpendicular to a frontrear direction of the marine vessel, of a hull bottom at a rear portion of a hull of the marine vessel has a V-shape.
17. The marine vessel steering system according to claim 11, wherein a cross-section, perpendicular to a frontrear direction of the marine vessel, of a hull bottom at a rear portion of a hull of the marine vessel has a V-shape.
18. The marine vessel steering system according to claim 12, wherein a cross-section, perpendicular to a frontrear direction of the marine vessel, of a hull bottom at a rear portion of a hull of the marine vessel has a V-shape.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A spectacle lens optical characteristic measuring method comprising: point-supporting left and right spectacle lenses of a pair of spectacles respectively by lens rests at some midpoints of optical paths of a pair of left and right measurement optical systems; retaining a spectacle frame for the spectacle lenses from front and rear sides by a pair of frame retaining members; pressing the spectacle lenses in this state against the lens rests by lens presser members to correct the way the spectacle frame is retained by the frame retaining members; retracting the lens presser members from the optical paths of the measurement optical systems; measuring measurement beams around the lens rests transmitted through the spectacle lenses by the measurement optical systems; and obtaining optical characteristics of the spectacle lenses on the basis of a measurement signal from the measurement optical systems by a computation control circuit.
2. A lens meter comprising: a pair of left and right lens rests capable of point-supporting left and right lenses of a pair of spectacles; a pair of frame retaining members capable of holding a spectacle frame of the pair of spectacles, whose lenses are supported by the lens rests, from front and rear sides; lens presser members for pressing the spectacle lenses supported by the lens rests against the lens rests; a pair of left and right measurement optical systems for measuring optical characteristics of the spectacle lenses supported by the lens rests on the basis of measurement beams passing around the lens rests; and a computation control circuit which controls the measurement optical systems to cause it to execute the measurement and which obtains the optical characteristics of the spectacle lenses on the basis of measurement signals from the measurement optical systems,
the lens meter further comprising presser member driving means for moving the lens presser members to pressing positions where they press the spectacle lenses against the lens rests and to retracted positions where they are retracted from the pressing positions,
wherein the computation control circuit controls the measurement optical systems upon movement of the lens presser members to the retracted positions by the presser member driving means so as to cause them to execute measurement of the optical characteristics of the spectacle lenses.
3. A lens meter according to claim 2, wherein the pair of frame retaining members have opposing surfaces tapered so as to be inclined downwardly.
4. A lens meter according to claim 2 or 3, further comprising frame detecting means provided between the pair of frame retaining members and adapted to detect the spectacle frame of the spectacle lenses supported by the lens rests and retaining member driving means for driving the pair of frame retaining members so as to move them toward and away from each other,
wherein the computation control circuit operationally controls the retaining member driving means upon detection of the spectacle frame by the frame detecting means so as to move the pair of frame retaining members toward each other to cause them to hold the spectacle frame, and operationally controls the presser member driving means so as to move the lens presser members to the pressing positions to press the spectacle lenses against the lens rests, and then move the lens presser members to the retracted positions.
5. A lens meter according to claim 4, wherein the frame detecting means is further equipped with a nose pad support member for supporting nose pads of the pair of spectacles which is arranged between the pair of left and right measurement optical systems and movable in the back and forth direction, biasing means for forwardly biasing the nose pad support member, and a detecting switch which detects backward movement of the nose pad support member against the biasing force of the biasing means.