Abstract: A method of measuring a lens comprises an aligning step of relatively aligning a plurality of specified annular zones on a surface of the lens with predetermined positions, and a determining step of determining an aspherical axis of the target surface aligned in the aligning step.

Abstract: A power transmission control system for a four-wheel drive vehicle powered by an engine has a transmission for transmitting the power of the engine to main driving wheels of the four-wheel drive vehicle, and a clutch for transmitting the power to auxiliary driving wheels. A hydraulic circuit for operating the clutch and a solenoid operated valve are provided for operating the clutch.Speed sensors are provided for detecting speeds of the main and auxiliary driving wheels in order to detect the slipping of wheels and vehicle speed.A steering angle is sensed for detecting a large steering angle. An electric circuit is provided to respond to the output of the speed sensors at slipping for engaging the clutch and to respond to large steering angle at low vehicle speed for disengaging the clutch for providing two-wheel driving.

Abstract: A system for controlling a power transmission of a four-wheel drive vehicle powered by an engine has a transmission for transmitting the power of the engine to main driving wheels of the four-wheel drive vehicle, a hydraulically operated clutch for transmitting the power to auxiliary driving wheels, a hydraulic circuit for operating the clutch in accordance with driving conditions. The system comprises a sensor for detecting the inclination of roads and for producing an output signal dependent on the inclination, and a control circuit responsive to the output signal from the sensor for engaging the clutch when the output signal exceeds a predetermined value, thereby establishing the four-wheel drive.

Abstract: A system for controlling power transmission of a four-wheel drive vehicle powered by an engine. The vehicle is provided with a transmission for transmitting a power of the engine to main wheels and a clutch for selectively transmitting the power to auxiliary wheels. In order to detect sudden braking of the vehicle, a vehicle speed sensor and a control circuit for detecting deceleration of the vehicle greater than a predetermined value are provided, the control circuit producing an output signal. A switch is provided responsive to the output signal for engaging the clutch, whereby the four-wheel driving power transmission is established.

Abstract: A system for controlling a power transmission of a four-wheel drive vehicle powered by an engine has a transmission for transmitting the power of the engine to main driving wheels of the four-wheel drive vehicle, and a clutch for transmitting the power to auxiliary driving wheels. A hydraulic circuit and a solenoid operated valve are provided for operating the clutch.First sensors are provided for detecting the speed of the main and auxiliary driving wheels, respectively, and second sensors are provided for detecting depression of an accelerator pedal and depression of a brake pedal of the vehicle respectively. When a large difference between the speed of the wheels is detected, the clutch is engaged, and when a large acceleration and large deceleration dependent on the output of the first sensors are detected, the clutch is engaged for establishing the four-wheel drive.

Abstract: A system for controlling a power transmission of a four-wheel drive vehicle powered by an engine. The system is provided with a transmission for transmitting a power of the engine to main wheels, a clutch for selectively transmitting the power to auxiliary wheels, a vehicle speed sensor for sensing the speed of the vehicle and for producing a vehicle speed signal dependent on the speed, a steering angle sensor for sensing the steering angle of the vehicle and for producing a steering angle signal dependent on the steering angle. A control circuit is provided to compare the vehicle speed signal and steering angle signal with reference values and judge whether the condition is in the range of conditions causing tight corner braking and to produce a clutch signal. A switch is responsive to the clutch signal for disengaging the clutch, whereby the four-wheel drive is changed to the two-wheel drive.

Abstract: A gearshift system for an automobile with an electromagnetic powder clutch and a transmission having four forward-gear sets. The system comprises a first synchronizing device for selectively engaging a second speed gear and a fourth speed gear with an output shaft of the transmission, a second synchronizing device for selectively engaging a first speed gear and a third speed gear with the output shaft, a first shifter arm for operating the first synchronizing device, and a second shifter arm for operating the second synchronizing device. A select lever is provided to engage one of the first and second shifter arms. The select lever is operated by a manual shift lever for shifting one of the shifter arms. Further, the select lever is moved by an electric actuator so as to engage with one of the shifter arms for the selection of the synchronizing device.

Abstract: A gearshift system for an automobile with an electromagnetic powder clutch and a transmission having four forward-gear sets. The system comprises a first synchronizing device for selectively engaging a second speed gear and a fourth speed gear with an output shaft of the transmission, a second synchronizing device for selectively engaging a first speed gear and a third speed gear with the output shaft, a first shifter arm for operating the first synchronizing device, and a second shifter arm for operating the second synchronizing device. A select lever is provided to engage one of the first and second shifter arms. The select lever is operated by a manual shift lever for shifting one of the shifter arms. Further, the select lever is moved by an electric actuator so as to engage with one of the shifter arms for the selection of the synchronizing device.

Abstract: A gearshift apparatus for an automobile with an electromagnetic powder clutch and a transmission having four forward-gear trains. The apparatus comprises a first synchronizing device for selectively engaging a second speed gear and a fourth speed gear with an output shaft of the transmission, a second synchronizing device for selectively engaging a first speed gear and a third speed gear with the output shaft, a shift lever for operating the first synchronizing device and the second synchronizing device. An actuating rod is provided for operatively connecting the shift lever with the first and second synchronizing devices. The shift lever is rotatably supported on a holding lever which is rotatably about an axis. The axis is substantially coaxial with the actuating rod. The holding lever is held in a range for operating the first synchronizing device and a range for operating the second synchronizing device by engagement of a spring loaded ball and in grooves.

Abstract: A system for a four-wheel drive vehicle for automatically changing a power transmission of the engine of the vehicle from two-wheel drive system to four-wheel drive system in accordance with road surface condition and driving condition. The transmission system is provided for transmitting a power from the engine to two main driving wheels, and a clutch is provided for transmitting the power of the engine to drive two other wheels. Speed sensors are provided for producing output signals dependent on speeds of the four wheels, respectively. A steering-angle sensor is provided for producing an output signal dependent on the steering-angle. Computation circuits are provided to compute an actual slip rate from the output signals of the speed sensors and to compute a theoretical slip rate from the output of the steering-angle sensor.

Abstract: A system for preventing the overheating of an electromagnetic clutch of an internal combustion engine mounted on a vehicle caused by slipping of the clutch for a considerably long time. The electromagnetic clutch has a drive member secured to a crankshaft of the internal combustion engine, a driven member adjacent to the drive member, and a magnetizing coil provided in one of said members. The heat quantity generated in the clutch is calculated by an operation circuit. A clutch current control circuit is provided such that when the heat quantity exceeds a predetermined value, the electromagnetic clutch is applied with a rated clutch current to engage the clutch without slipping for preventing overheating by the slipping.

Abstract: An electromagnetic clutch has a drive member secured to a crankshaft of an internal combustion engine, and a driven member adjacent to the drive member. The system comprises a circuit for detecting the difference between numbers of revolutions of the drive member and driven member, a comparator for producing an output when the difference is higher than a reference value, a timer operated by the output of the comparator, and a warning device such as a buzzer operated by the signal from the timer when a predetermined time elapses. Thus, when the clutch slips, the warning signal is generated. Further, a circuit for changing clutch engaging characteristics is provided to be operated by the output of the comparator for preventing the overheating of the clutch.

Abstract: A system for a four-wheel drive vehicle for automatically changing a power transmission system of the engine of the vehicle from four-wheel driving system to two-wheel driving system in accordance with the steering angle during the turning of a corner. The transmission system is provided for transmitting a power from the engine to main driving two-wheel, and a fluid pressure controlled friction clutch is provided for transmitting the power of the engine to two wheels other than the main driving two-wheel. A steering angle sensor is provided for producing a steering angle signal dependent on the steering angle. A control system is provided to respond to the steering angle signal for decreasing the pressure of the pressure oil applied to the clutch thereby to cause the slip of the clutch during the turning of the corner.

Abstract: A system for preventing overheat of an electromagnetic clutch of an internal combustion engine mounted on a vehicle, which has a drive member secured to a crankshaft of the internal combustion engine, magnetizing coil provided in the drive member, a driven member adjacent to the drive member, and a transmission secured to the driven member. A detecting circuit is provided for detecting the temperature of the clutch for producing an electrical output. An electric circuit is provided to respond to the output of the detecting circuit for rapidly increasing the clutch current, so that the clutch is entirely engaged in a short time, whereby the overheat by slippage of the clutch may be prevented.