When one travels in an elevator in a tall building, the air pressure changes so much that the elevator passenger can feel it as an unpleasant sensation in the ears. This unpleasant sensation is more intensive when the air pressure is increasing, i. e. during down- ward travel. The unpleasant sensation in the ear is due to the fact that the pressure in the inner. ear cannot change and be equalized at the rate of change of the external pressure, with the result that the pressure difference between the inner ear and the ex- ternal space increases. The pressure in the inner ear is equalized with a time constant of about 30-30 sec- onds. Thus, on the one hand, the pressure difference producing an unpleasant sensation depends on the ele- vator speed and, on the other hand, on the distance of continuous ride and on the traveling direction.

The elevator industry has developed physiological limits that the elevator passenger can tolerate with- out excessive discomfort. The discomfort limit of the pressure change in the ear is a pressure difference of the order of 2000 Pa. In general, the discomfort limit is approached when the car speed during downward travel is of the order of 7 m/s and the vertical dis- tance traveled exceeds 160 m. The easiest way to eliminate the problems due to the pressure difference would be to limit the hoist speed to 10-15 m/s and to keep the velocity of descent at about 7 m/s. An- other alternative would be to use intermediate stops or sky-lobby pauses and perhaps pressurized rest rooms in conjunction with these. Suitable pressurized spaces

could also be used even before the passenger enters the elevator, in which case the entire elevator trip could be accomplished as a continuous ride without breaks.

Previously known methods for eliminating the above- described problems either significantly reduce the transport capacity of the elevator because of low speeds or are complicated and expensive to implement.

As an example of prior-art technology, reference is made to Japanese specification JP A 07112876, which presents an elevator control method for preventing or reducing the discomfort caused by air pressure varia- tions in the passenger's ears. When the traveling dis- tance does not exceed a certain limit, the elevator is operated at normal speed. When the distance is longer than this, the speed of the elevator is set to a level lower than normal.

The object of the present invention is to eliminate the problems referred to above. A specific object of the invention is to disclose a new type of elevator control method which allows the use of top speeds con- siderably exceeding 10 m/s without causing any un- pleasant sensation in the passengers'ears. Another object of the invention is to enable the transport ca- pacity of the elevator to be increased without impair- ing traveling comfort.

As for the features characteristic of the invention, reference is made to the claims.

The elevator control method of the invention reduces the feeling of discomfort in the passenger's ears caused by air pressure variations. According to the

invention, a discomfort limit of the pressure differ- ence between the passenger's inner ear and the inte- rior space of the elevator car is determined. After this, the elevator car is first accelerated to its traveling speed to be used at first, and when the speed of the elevator car is approaching the discom- fort limit of the pressure difference, the speed is reduced so as not to exceed the discomfort limit.

Thus, in the elevator control method of the invention, the elevator is always at first accelerated to a cer- tain traveling speed, which preferably is over 10 m/s, even over 14 m/s. In other words, in the method of the invention, the distance of continuous travel is not taken into account at first; instead, the elevator is always started at a given traveling speed and care is taken that the specified discomfort limit of the pres- sure difference is not exceeded. Thus, for short dis- tances, the normal traveling speed can be used for the whole distance.

The traveling speed used is preferably the structural top speed of the elevator, in other words, the eleva- tor is always started at maximum speed. Furthermore, the control method of the invention takes into account the situation where, even if the continuous traveling distance at first seems so long that the elevator can- not be driven at top speed through the entire dis- tance, it is possible that a car call or landing call given during the trip will cause an intermediate stop, which would have resulted in wrong control or too low a speed if the original long traveling distance had been used as a criterion of control of traveling speed.

Another possibility is to define the traveling speed or top speed to be used by the elevator so that the

speed is higher for upward travel than for downward travel, because the discomfort limit is clearly lower when the air pressure is increasing, i. e. when the elevator is traveling downward.

In the control method of the invention, the measure- ment of the pressure difference prevailing between the passenger's inner ear and the interior space of the elevator car to determine whether the discomfort limit is being approached can be implemented in many differ- ent ways or by suitably combining different ways. Of course, it is possible to measure the pressure and the rate of change of the pressure in the elevator car, keeping the rate of change at a sufficiently low level. The pressure difference can also be estimated with a sufficient accuracy on the basis of the top traveling or structural speed and the time of use of the top traveling or structural speed, by also taking into account the traveling direction of the elevator, the distance to be traveled continuously, the average rate of equalization of the pressure in the ear, as well as the air pressure outside the elevator car when relatively airtight elevator cars are used. By measur- ing, estimating or studying one or more of the above- mentioned factors, it is possible to determine the pressure difference prevailing in the elevator passen- ger's ear with a sufficient accuracy and to prevent the car from exceeding the discomfort limit of this pressure difference.

It is also possible to estimate the pressure differ- ence between the passenger's inner ear and the inte- rior space of the elevator car by using an apparatus simulating the behavior of the inner ear. A further possibility in the method of the invention is to pro- vide e. g. the elevator car with a regulator which the

passenger can use him/herself to adjust the pressure difference discomfort limit observed by the control system. This will make it possible e. g. for people having a cold, for whom the time constant of equaliza- tion of the pressure in the inner ear is generally clearly longer than the normal 20-30 m/s, to avoid feeling annoying pain in fast elevators.

As compared with prior art, the elevator control method of the invention has significant advantages.

Using the control method of the invention, it is pos- sible to apply a considerably higher traveling or structural top speed of the elevator than is possible with previously known control methods. Therefore, es- pecially for shorter traveling distances, it is possi- ble to use a high top speed throughout the traveling distance, which significantly increases the capacity of the elevator. For longer distances as well, the initial high top speed guarantees that the traveling times of the elevator car become shorter and its ca- pacity is increased without producing any adverse ef- fects on the passengers'traveling comfort.

In the following, the invention will be described in detail with reference to the attached drawing, which presents a diagram representing a certain phase in the elevator control method of the invention.

If a fast elevator traveled in the traditional manner through a relatively long distance, its traveling speed would be kept at a constant 7 m/s so that the pressure difference prevailing in the passenger's in- ner ear would not rise above the discomfort limit of 2000 Pa (dotted line).

In the control method of the invention, the traveling speed of the elevator is at first increased to a level clearly exceeding this traditionally safe maximum speed of 7 m/s, even to a speed as high as 14 m/s. At the same time, the development of the pressure differ- ence between the passenger's inner ear and the eleva- tor car is monitored to establish whether the pressure difference is approaching the discomfort limit. When the pressure difference reaches a value close to the discomfort limit, in this example 2000 Pa, the car speed is reduced to e. g. 6 m/s, which has the effect that the pressure difference stops growing and remains below the specified discomfort limit. Even though the elevator travels through the remaining distance at a speed lower than the traditional car speed, the total travelling time of the elevator car is shortened, thus improving the capacity of the elevator.

In the control method described above, the saving in time is significant as compared with prior art, espe- cially when the elevator receives a landing call while traveling and stops e. g. before it has lowered its speed. Thus, when departing again, it can again travel at top speed as the pressure difference has been suf- ficiently equalized during the stops.

In the foregoing, the invention has been described by way of example by the aid of the attached drawing while different embodiments of the invention are pos- sible in the scope of the inventive idea defined in the claims.