Motor vehicles – Vehicle trains – Tractor drive effort varied by pull exerted by trailer
Patent
1990-04-11
1991-09-17
Marmor, Charles A.
Motor vehicles
Vehicle trains
Tractor drive effort varied by pull exerted by trailer
180904, 36442601, B62D 5300
Patent
active
050486250
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for preventing overloading of nose wheel gears of aircraft being towed by a tractor.
The specification of U.S. Pat. No. 4,113,041 describes a method and a control system whereby the force being transmitted between tractor and aircraft is continuously sensed and whereby subsequently on the basis of the sensed value the braking and the output effect of the tractor are controlled in a superior manner so that the transmitted force is kept within a pre-determined interval. Using this system it is possible for the pilots of the aircraft to brake by means of the brakes of the aircraft in that the tractor will always automatically follow the aircraft in its acceleration and deceleration. The system is applicable when using a towbar and in connection with that type of tractors where the nose wheel of the aircraft is supported on the tractor. This type of tractor has spread and it has thus turned out that the nose wheel gears have such great strength that it is actually possible without the mentioned automatic control link with the aircraft to decelerate the tractor from speeds of 30 km/h without damaging said gears. This is among other things due to the fact that the tractor will not necessarily have to be so big when the nose wheel is supported thereon. When the nose wheel is supported on the tractor, it is not quite so easy to sense the transmitted pulling force, ie. to register when the aircraft is braking.
It is the object of the present invention to provide a more simple method of sensing than just measuring the transmitted force.
The characteristic feature of the method is that the acceleration or deceleration in longitudinal direction of the tractor is continuously sensed, and that the values obtained are used for reducing the power supplied by the tractor and if required to activate the brakes of the tractor if a deceleration above a certain value is sensed.
It is thereby possible to carry out the towing at a speed above 30 km/h without involving any danger to the nose wheel gears.
The method may moreover be characteristic in that the power is zeroed if there is a deceleration or perhaps a deceleration of a certain value. If the engine power of the tractor is fully disconnected when the aircraft brakes, the nose wheel gears will solely have to absorb the inertia forces originating from the tractor and that will be acceptable by smooth brakings and by large aircraft.
By further improvements in the method these forces are fully compensated for since the method is characteristic in that a value being a function of the supplied power of the tractor, for example the moment on the drive shafts or the fuel consumption, is also continuously sensed, that on the basis of the sensed values and the mass of the tractor the pulling force transmitted to the aircraft is continuously calculated, and that the power or braking of the tractor is controlled in such a manner that the pulling force is constantly kept within a pre-determined, permissible interval.
According to the invention an interval of solely positive forces, ie. pulling forces between tractor and aircraft will preferably be chosen. There is thus guarded against the socalled jack knifing which may be very dangerous by overrun, ie. if the aircraft for example due to wind forces or variations in the ground, happens to run faster than the tractor ie. tries to push the tractor. The method of the invention will in that case forestall such incident and provide an acceleration of the tractor. This fact is of course of vital importance on slippery runways.
The invention also relates to a tractor for carrying out the method and this tractor is characterised by being equipped with an accelerometer for sensing in longitudinal direction. The driver of the tractor can then when reading the accelerometer take the required measures for reducing the speed of the tractor. Usually such a tractor will be equipped with constant speed control for the engine or the engines and there will be fixed settings of the power, ie. the driver will not be req
REFERENCES:
patent: 2521503 (1950-09-01), Clark
patent: 2790365 (1957-04-01), Bunting
patent: 3005509 (1961-10-01), Nolan
patent: 4070562 (1978-01-01), Kuno et al.
patent: 4113041 (1978-09-01), Birkeholm
patent: 4225279 (1980-09-01), Boyer
patent: 4232372 (1980-11-01), Berent
patent: 4375244 (1983-03-01), Morin
patent: 4627011 (1986-12-01), Spencer
patent: 4723078 (1988-02-01), Neuffer et al.
FAN, Henry S. L. and HANEY, Dan G., AIRCRAFT TOWING FEASIBILITY STUDY, Paper Presented at Symposium on Commercial Aviation Energy Conservation Strategies, Apr. 2-3, 1981, Cosponsored by U.S. Department of Energy and Federal Aviation Administration (DOE/FAA).
Boehler Anne M.
Marmor Charles A.
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