JPH10203488A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device formed such that a pilot can be easily seated in a seat, and the pilot can be easily separated from the seat. SOLUTION: A control unit U of a control device 10 is connected to a side part of a seat 11, to rise up in a prescribed position 20. The control unit U of this control device 10 is provided able to make displacement between the prescribed position 20 and a refuge position, in this way, by a pilot 13, for instance, at on/off getting time or the like in an airframe, as necessary, the control unit U can be displaced to the refuge position. Accordingly, by the pilot 13, at the time of seating in or leaving from the seat 11, the control unit U is displaced, a wide space for moving is obtained, the control unit U can be prevented from interfering with a foot or the like of the pilot 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aircraft control device provided on a side of a pilot seat.

[0002]

2. Description of the Related Art Fly-by-wire (Fly By Wire) systems are often used in aircraft such as helicopters, and accordingly, pilots are placed on the sides of the seats where the pilots are seated. A control device called a side stick control device, which includes a control unit having a stick operated by the user and a housing provided with the stick, is employed. This control device raises the control unit from the seat plate to the side of the seat, so that the pilot can sit on the seat and grip the stick in a posture that does not burden the body. Is configured.

[0003]

As described above, in such a prior art steering apparatus, since the steering unit rises upward from the seat plate of the seat, as described above, for example, when the pilot gets on and off the vehicle, the pilot can use it. When the user sits on or leaves the seat, the pilot unit may interfere with the pilot's feet or the like, making the above-described operation difficult. In particular, in the case of aircraft, such as helicopters, which are provided with entrances and exits beside the seats, it is desirable to be able to quickly and safely leave the seats so that they can escape from the aircraft promptly in an emergency exit. It is rare. Further, if a control unit, particularly a stick, interferes with a foot or the like, there is a possibility that a failure of the control device may be caused.

[0004] Accordingly, an object of the present invention is to provide a pilot control device that can prevent a pilot from interfering with the pilot's feet or the like when sitting on a seat and when leaving the seat. is there.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a control device for controlling an aircraft, which is provided standing upright at a predetermined position on a side of a seat where a pilot is seated and operated by the pilot. A control unit having a control input unit, a sensor for detecting control information provided to the control input unit, and a housing in which a feeling unit for providing a control feel to the control input unit is housed; A steering device is provided so as to be displaceable between a retreat position retracted from a predetermined position. According to the present invention, the steering unit has a steering input unit and a housing, and the housing accommodates a sensor and a field means, and the pilot operates the steering input unit to steer the aircraft. A control unit having a control input unit and a housing is provided standing upright at a predetermined position beside the seat, and the pilot sits on the seat and operates the control input unit in a posture that does not burden the body. Can steer the aircraft. The control unit of such a control device can also be displaced between a predetermined position and a retracted position retracted from the predetermined position, so that the pilot can control the control as required, for example, when getting on or off the aircraft. The unit can be displaced to the retracted position. Thus, the pilot displaces the pilot unit when seated in or away from the seat, gaining a large space for movement, and the pilot device interferes with the pilot's feet, etc. Can be prevented.

According to the present invention, in the steering unit, the rear end is connected to the seat by hinge means, and the front end is angled around the vertical axis from the predetermined position to the retracted position in a direction away from the seat. It is provided so as to be displaceable, and when at a predetermined position, is further locked to the seat by locking means. According to the present invention,
The steering unit is provided with a rear end portion capable of being angularly displaced around a vertical axis by hinge means, and can be displaced from a predetermined position toward a retreat position in a direction in which a front end portion moves away from the seat. As a result, the front end of the steering unit is displaced rearward, and a wide space can be obtained on the side of the seat near the front. Further, the pilot makes angular displacement of the housing by, for example, gripping the vicinity of the front end of the piloting unit while sitting on the seat, and angularly displacing the arm around the elbow or shoulder in the left-right direction. And the steering unit can be easily angularly displaced. Furthermore, when the control unit is at the predetermined position, the control unit is locked by the locking means, so that the control unit is firmly held on the seat and is fixed at the predetermined position without undesired displacement of the control unit. be able to.

Further, according to the present invention, the steering unit is connected to the seat by linear guide means, and is slidably provided rearward from a predetermined position to a retracted position.
When at the predetermined position, it is further locked to the seat by the locking means. According to the present invention, the steering unit is slidably provided, and the entire steering unit is displaced rearward from the predetermined position toward the retreat position. Thereby, a wide space can be obtained on the side of the seat from the front side. In addition, the pilot can easily slide and displace the control unit by displacing the arm back and forth along the body, for example, by gripping the vicinity of the front end of the control unit while sitting on the seat. . Further, when the control unit is in the predetermined position, the control unit is locked by the locking means, so that the control unit can be firmly held in the seat and fixed in the predetermined position without undesired displacement of the control unit. it can.

Further, in the present invention, the steering unit may be configured such that a lower end portion is connected to the seat by a hinge, and an upper end portion extends around a horizontal axis extending in a front-rear direction from a predetermined position to a retracted position in a direction away from the seat. It is provided so that it can be angularly displaced, and when it is at a predetermined position, it is further locked to the seat by locking means. According to the present invention, the steering unit is provided such that the lower end is angularly displaceable around a vertical axis extending in the front-rear direction by the hinge means, and the upper end is displaced from the predetermined position toward the retreat position in a direction away from the seat. Is done. by this,
The upper end of the steering unit is displaced downward, so that a large space can be obtained on the upper side of the seat. Also,
The pilot can easily make angular displacement to the retreat position by pushing near the upper end of the pilot unit while sitting in the seat. Further, when the control unit is at the predetermined position, the control unit is locked by the locking means, so that the control unit can be firmly held on the seat and fixed at the predetermined position without undesired displacement of the control unit. it can.

Further, according to the present invention, in the steering unit, a rear end portion near the lower end portion is connected to the seat by a hinge, and a front end portion extends around a horizontal axis extending leftward and rightward from a predetermined position to a retracted position. It is provided so that it can be angularly displaced, and when it is at a predetermined position, it is further locked to the seat by locking means. According to the invention, the steering unit is provided such that the rear end thereof is angularly displaceable about an axis extending in the left-right direction by the hinge means, and the front end is displaced upward from the predetermined position toward the retracted position. As a result, the front end of the control unit is displaced rearward, and a wide space can be obtained on the front side of the seat. In addition, the connection is made closer to the lower end of the rear end, so that the space near the front of the seat increases. further,
When the control unit is at the predetermined position, the control unit is locked by the locking means, so that the control unit can be firmly held on the seat and fixed at the predetermined position without undesired displacement of the control unit.

[0010]

FIG. 1 is a perspective view showing a seat 11 provided with a steering device 10 according to one embodiment of the present invention. FIG. 2 is a perspective view of the seat 11 viewed from a direction different from FIG.
FIG. An anti-torque tail rotor type helicopter, which is an aircraft, has a cockpit floor 12
A seat 11 on which a pilot 13 sits is provided. The control device 10 is a control device provided, for example, on the right side of the seat 11, and is a side stick type control device called a side stick controller or the like as the fly-by-wire system is adopted for the control system. 10 is adopted.

The control device 10 is a device for operating and controlling, for example, the forward and backward movement of the fuselage and the lateral movement of the fuselage. A stick 15 which is a control input unit operated by a pilot 13 and the stick 15 are provided. And a control unit U having a housing 16 provided therein. The stick 15 is provided on the upper part of the housing 16 so as to be capable of angular displacement operation, and the pilot 13 can give steering information by performing the angular displacement operation. In the housing 16, a sensor for detecting steering information given to the stick 15, that is, an angular displacement angle, and a steering feel, that is, a feel means for giving a steering feeling to the stick 15 are housed. When the pilot 13 operates the stick 15,
The angular displacement angle is detected by the sensor, and the pilot 13
In response to the operation of the stick 15, the cyclic pitch of the main rotor is controlled, and the aircraft is steered so as to move forward or backward, or to move left and right.

The control unit U having the stick 15 and the housing 16 is provided at a predetermined position 20 on the side of the seat 11, and when in the predetermined position 20, the upper end 23 of the control unit U The seat 15 stands above the seat plate 18 of the seat 11, and the stick 15 is provided near the front of the upper portion of the housing 16, so that the pilot 13 sits on the seat 11 and does not burden the body. In the posture, the stick 15 can be gripped and operated.

FIG. 3 is a perspective view showing the seat 11 with the steering device 10 removed. Referring also to FIGS. 1 and 2, a bracket 30 is fixed to the right side of the seat 11 near the rear.
Has a hinge pin 3 having an axis L1 extending in the vertical direction.
1 is formed. The control unit U of the control device 10
The hinge pin 31 is inserted through the rear part of the housing 16 which becomes the rear end part 26 of the control unit U, and the hinge pin 30 is provided on the seat 11 so as to be angularly displaceable about the axis L1 around the hinge pin 30. A latch box 33 is provided at the front of the housing 16 which is the front end 25 of the control unit U, and an engagement protrusion 34 is formed at the right side of the seat 11 near the front, so that the horizontal support portion is formed. A bracket 35 having 36 is fixed.

As described above, the control unit U is connected by the hinge means, and is located at the predetermined position 20 shown in FIGS.
4 and FIG. 5 in which the front end 25 is retracted from the predetermined position 20 in the direction away from the seat 11. Further, the latch box 33 has a pair of engaging claws 37a, 37b. When the control unit U is at the predetermined position 20, the engaging claws 37a, 37b engage with the engaging protrusions 34, thereby the front end. The part 25 is further locked to the seat 11. In this state of being locked by the locking means, the lower portion near the front of the housing 16 which is the lower end 24 near the front end 25 of the control unit U is supported by the support portion 36 of the bracket 35. In this way, the control unit U can be firmly fixed to the seat 15 at the predetermined position 20 so as not to be undesirably displaced. The latch box 33 has an opening lever 38, and by operating this opening lever 38, it is possible to easily release the locked state of the front end 25 of the control unit U to the seat 11. .

On the left side of the seat 11, another controller 40 for operating and controlling, for example, lifting and lowering of the body is provided. The controller 40
It has a control lever 41, and this control lever 41 is
By performing the angular displacement operation of 3, the collective pitch of the main rotor is controlled, and the aircraft is steered so as to ascend or descend.

A floor 12 is provided in front of the seat 11.
In the vicinity, for example, a pair of control pedals 45a and 45b for operating and controlling the direction of the nose is provided. By operating each of the steering pedals 45a and 45b individually, the pitch of the tail rotor is controlled, and the aircraft is steered so that the nose turns left or right.

Further, in the cockpit, as shown in FIG. 6, a seat 50 is provided adjacent to the seat 11, for example, for the first officer to sit down. An instrument panel 51 provided with instruments for displaying a flight state and surrounding conditions is provided. A center pole 52 and side posts 53a and 53b are provided between the seats 11 and 50 and on the sides. As described above, the cockpit is provided with many devices and body components such as devices necessary for operating the body. Therefore, the space for the pilot 13 to move in the cockpit is small,
The control unit U and, consequently, the control device 10 may be in the way. For example, as shown in FIG. 7, when the operator gets on and off from an entrance 56 formed by opening a door 55 provided on the side of the seat 11 as shown in FIG. 11
When the control unit U remains fixed at the predetermined position 20 when the user sits on the vehicle or leaves the seat 11, as described above, the control unit U
Will interfere.

On the other hand, in the control device 10 of the present embodiment,
The control unit U is provided so as to be displaceable between a predetermined position 20 and an evacuation position 21 retracted from the predetermined position 20, so that the pilot 13 can control the control unit U as needed.
Can be displaced to the evacuation position 21 and the seat 11 can be displaced.
A large space can be obtained on the side of. Moreover, in this embodiment, the front end portion 25 of the control unit U is displaced rearward, so that a wide space can be obtained on the side of the seat 11 closer to the front. Further, the pilot 13, while sitting on the seat 11, grips the vicinity of the front end 25 of the control unit U, and angularly displaces the arm in the left and right direction about the elbow or shoulder, thereby controlling the control unit. U can be easily angularly displaced.

Therefore, the pilot 13 displaces the control unit U to the retreat position 21 when getting on and off, so as to obtain a large space for the pilot 13 to move in the cockpit, and to use the pilot's 13 feet and the like. In addition, it is possible to prevent the operation unit U from interfering, and to easily sit on the seat 11 or separate from the seat. In particular, even in the case of escape from the cockpit to the outside of the aircraft in an emergency, the escape can be performed quickly and safely. In addition, it is possible to avoid damage to the control device 10 which is a precision machine, in particular, the stick 15 protruding from the housing 16. Further, since the control unit U can be angularly displaced between the predetermined position 20 and the retreat position 21, the maintainability of the control unit U is improved. When the hinge pin 31 is used, for example, the hinge pin 31 can be easily removed from the seat 11 by extracting the hinge pin 31, thereby further improving the maintainability.

Further, the control unit U is moved to a predetermined position 20.
, The front end 25 is locked to the seat 11 by the locking means including the latch box 33 and the engagement projection 34, so that the steering unit U is undesirably displaced by, for example, vibration during flight. It can be fixed at the predetermined position 20 so as not to cause such troubles. Therefore, there is no danger that the maneuverability is impaired, and there is no possibility of causing a failure. Also, the control unit U
Is connected to the seat 11 by hinge means having hinge pins 31, so that an angular displacement mechanism for retracting the control unit U can be realized at low cost. Further, also for the latch box 33, it is possible to use a latch mechanism provided for a door of a four-wheeled motor vehicle, which is easily available commercially, and is easy to manufacture.

FIG. 8 is a perspective view showing a seat 11 provided with a steering device 10a according to another embodiment of the present invention.
FIG. 9 is a perspective view showing the seat 11 viewed from a different direction from FIG. The control device 10a has a configuration similar to that of the control device 10 of the above-described embodiment. Only different configurations will be described, and portions having the same configuration will be denoted by the same reference numerals and description thereof will be omitted. I do. The control unit U
A pair of linear sliders 60a, 60 which are linear guide means;
b, and is slidably provided between a predetermined position 20 and a retracted position 21a.

Each of the linear sliders 60a and 60b is fixed to the side of the seat 11 with a space therebetween in a vertical direction and a pair of guide rails 61a and 61b fixed to the housing 16 and movably provided on the guide rails 61a and 61b. It has moving pieces 62a and 62b to be fitted. Each guide rail 61
a, 61b are provided extending in the front-rear direction, and the control unit U can be slid rearward from the predetermined position 20 along the guide rails 61a, 61b toward the retreat position 21a.

A latch box 33a is provided near the front end 25 of the control unit U, and a bracket 35a having an engagement projection 34a is fixed to the right side of the seat 11 near the front, and the control unit U is controlled. When the unit U is at the predetermined position 20, the latch box 3
The front end 25 is locked to the seat 11 by engaging the respective claw members 37a and 37b of 3a with the engagement protrusions 34a.

The steering device 10a can also provide a wide space on the front side of the seat 11 similarly to the steering device 10 of the above-described embodiment. Further, the pilot 13 can easily slide and displace the control unit U by displacing the arm in the front-rear direction, for example, by gripping the vicinity of the front end of the control unit U while sitting on the seat 11. Thus, the same effect as that of the control device 10 can be obtained. Further, the linear sliders 60a and 60b for connecting the control unit U are easily available commercially, and are easy to manufacture as in the case where the hinge pin 31 is used.

FIG. 10 is a perspective view showing a seat 11 provided with a steering device 10b according to another embodiment of the present invention. FIG. 11 is a perspective view showing the seat 11 viewed from a different direction from FIG. It is. The control device 10b has a configuration similar to that of the control device 10 in the above-described embodiment. Only different configurations will be described, and portions having the same configuration will be described.
The same reference numerals are given and the description is omitted. The steering unit U is connected to the seat 11 by hinge means having hinge pins 31b fixed to a lower side of the seat 11, and is provided so as to be angularly displaceable between a predetermined position 20 and a retreat position 21b. .

Brackets 70 and 71 are fixed to the front and rear sides of the seat 11, respectively.
1b is provided. The hinge pin 31b has an axis L2 extending in the front-rear direction. The hinge pin 31b is inserted into a lower portion of the housing 16 which is the lower end 24 of the control unit U, and the control unit U is connected to the seat 11. Thus, the housing 16 is moved to the predetermined position 2.
From 0, the upper end portion 23 can be angularly displaced in the direction away from the seat 11 toward the retreat position 21b.

A latch box 33b is provided at the front end 25 of the control unit U, and an engagement protrusion 34b is formed at a bracket 70 fixed to the right side of the seat 11 near the front. When U is at the predetermined position 20, the front end 25 is locked to the seat 11 by engaging the respective claw members 37a and 37b of the latch box 33b with the engagement protrusions 34b.

By displacing the control unit U to the retracted position 21b, such a control device 10b can obtain a wide space on the upper side of the seat 11. Further, the pilot 13, while sitting on the seat 11, presses the control unit U easily by grasping the vicinity of the upper end 23 of the control unit U and pressing the control unit U sideways away from the body. Can be angularly displaced to the retreat position 21b, and the same effect as that of the control device 10 can be obtained. Further, similarly to the control device 10, it can be easily manufactured at low cost.

FIG. 12 is a perspective view showing a seat 11 provided with a steering device 10c according to another embodiment of the present invention, and FIG. 13 is a perspective view showing the seat 11 viewed from a different direction from FIG. It is. The control device 10c has a configuration similar to the control device 10 in the above-described embodiment. Only different components will be described.
The same reference numerals are given and the description is omitted. The maneuvering unit U is connected to the seat 11 by hinge means having hinge pins 31c fixed to the rear side of the seat 11, and is provided so as to be angularly displaceable between a predetermined position 20 and a retracted position 21b. A bracket 30c is fixed to the rear side of the seat 11, and a hinge pin 31c is provided on the bracket 30c. The hinge pin 31c has an axis L3 extending in the left-right direction. The hinge pin 31c is inserted into a lower rear portion of the housing 16 which is a rear end portion 26 closer to a lower end portion of the control unit U, and the control device 10c is seated. It is connected to the seat 11. In this way, the control unit U is moved to the front end 2
5 can be angularly displaced toward the retreat position 21c so as to jump upward.

A latch box 33c is provided at the front end 25 of the control unit U, and a bracket 35a is fixed to the front right side of the seat 11, and an engagement protrusion 34c is formed. When the control unit U is at the predetermined position 20, the latch box 3
The front end 25 is locked to the seat 11 by engaging the claw members 37a and 37b of 3c with the engagement protrusions 34c.

By displacing the control unit U to the retreat position 21c, such a control device 10c can obtain a wide space on the upper side of the seat 11 toward the front. Thereby, the control unit U is moved to the retreat position 21.
The same effect as that of the control device 10 can be obtained by angular displacement to c. Further, similarly to the control device 10, it can be easily manufactured at low cost.

As still another embodiment of the present invention, in each of the above-described embodiments, the control unit U is provided with a predetermined position 20.
The means for applying a spring force in the direction toward the evacuation positions 21 and 21a to 21c may be provided so that the control unit U can be easily displaced to the evacuation positions 21 and 21a to 21c. . Thereby, for example, at the time of emergency escape, it is possible to move away from the seat 11 more quickly and more easily. Further, the control unit U is moved to the predetermined position 20 and the respective retreat positions 21,
21a to 21c, the control unit U can be stabilized at the predetermined position 20, and each of the retreat positions 21, 21a to 21c can be stabilized.
Can be further facilitated. Further, the configuration for displaceably providing the control unit U is not limited to the above-described configuration. For example, the housing 16 can be displaced between the predetermined position 20 and the retracted position by another configuration such as a link mechanism. It may be configured to be provided, and the same effect can be obtained.

Each of the control devices 10, 10a, 10b,
Although 10c has been described as being provided in a tail rotor type helicopter for anti-torque, other embodiments of the present invention include, for example, a twin rotor type (coaxial inversion type, side-by-side type), and a tandem rotor type. May be implemented as a helicopter control device of the type described above. The invention is not limited to a helicopter, and may be implemented as a control device of another aircraft. In such a case, the same effect can be obtained. Furthermore, each of the control devices 10, 10a, 1
0b and 10c may be implemented in place of the controller 40, or may be implemented beside another seat 50, that is, as a steering device operated by the co-pilot. The effect can be obtained.

[0034]

As described above, according to the present invention, the steering unit can be displaced between the predetermined position and the retracted position,
A wide space can be obtained beside the seat. In addition, the steering unit can be easily displaced while sitting on the seat. Therefore, it is possible to easily sit on the seat or leave the seat without causing the control device to interfere with the pilot's feet or the like. In particular, even in the case of escape from the cockpit to the outside of the aircraft in an emergency, the escape can be performed quickly and safely. In addition, it is possible to avoid damage to the control device, which is a precision machine. Further, since the steering unit can be angularly displaced between the predetermined position and the retracted position, the maintainability of the steering unit and thus the steering device is improved.

Further, since the control unit U can be locked to the seat when it is at a predetermined position, it is possible to prevent the control unit U from being undesirably displaced due to, for example, vibration during flight. , Can be fixed at a predetermined position. Therefore, there is no danger that the maneuverability is impaired, and there is no possibility of causing a failure.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a seat 11 provided with a steering device 10 according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a seat 11 provided with a control device 10 as viewed from a direction different from FIG.

FIG. 3 is a perspective view of the seat shown in a state where the control device is removed.

FIG. 4 is a perspective view showing the seat 11 when the control device 10 is retracted to a retreat position 20 when viewed from the same direction as in FIG.

FIG. 5 is a perspective view showing the seat 11 when the control device 10 is retracted to the retreat position 20 when viewed from the same direction as in FIG.

FIG. 6 is a perspective view showing the entire cockpit in which the control device 10 is provided.

FIG. 7 is a side view showing the vicinity of the entrance 55 of the helicopter in which the control device 10 is provided.

FIG. 8 is a perspective view showing a seat 11 provided with a steering device 10a according to another embodiment of the present invention.

FIG. 9 is a perspective view showing a seat 11 provided with a control device 10a when viewed from a direction different from FIG.

FIG. 10 shows a steering device 1 according to still another embodiment of the present invention.
It is a perspective view which shows the seat 11 in which 0b is provided.

FIG. 11 is a view of a control device 10b viewed from a different direction from FIG.
FIG. 2 is a perspective view showing a seat 11 provided with.

FIG. 12 is a steering device 1 according to still another embodiment of the present invention.
It is a perspective view which shows the seat 11 in which 0c is provided.

FIG. 13 is a view of a control device 10c viewed from a different direction from FIG.
FIG. 2 is a perspective view showing a seat 11 provided with.

[Explanation of symbols]

 10, 10a, 10b, 10c Control device 11, 50 Seat seat 15 Stick 16 Housing 20 Predetermined position 21, 21a, 21b, 21c Retreat position 31, 31b, 31c Hinge pin 33, 33a, 33b, 33c Latch rail groove 34 Engagement projection U operation unit

Claims (5)

[Claims] 1. A control device for controlling an aircraft, comprising: a control input unit which is provided upright at a predetermined position on a side of a seat on which a pilot sits and is operated by the pilot; A steering unit having a sensor for detecting steering information given to the steering input unit and a housing in which steering means for giving a steering feel to the steering input unit are provided, wherein the steering unit has the predetermined position and the retreat position retracted from the predetermined position. A steering device, which is provided so as to be displaceable between the control members. 2. The steering unit according to claim 1, wherein a rear end of the steering unit is connected to the seat by hinge means, and a front end of the steering unit is angularly displaceable about a vertical axis from a predetermined position to a retracted position in a direction away from the seat. 2. The control device according to claim 1, wherein the control device is provided and, when in a predetermined position, is further locked to the seat by a locking means. 3. The steering unit is connected to the seat by linear guide means, and is slidably provided rearward from a predetermined position to a retracted position. When the control unit is at the predetermined position, the control unit is connected to the seat by a locking means. The control device according to claim 1, wherein the control device is further locked. 4. The steering unit, wherein a lower end is connected to the seat by a hinge, and an upper end is angularly displaced around a horizontal axis extending in a front-rear direction from a predetermined position to a retreat position in a direction away from the seat. 2. The control device according to claim 1, wherein the control device is provided so as to be capable of being further locked to the seat by a locking means when it is at a predetermined position. 5. The steering unit, wherein a rear end near a lower end is connected to the seat by a hinge, and a front end is angularly displaced upward from a predetermined position to a retracted position about a horizontal axis extending in the left-right direction. 2. The control device according to claim 1, wherein the control device is provided so as to be capable of being further locked to the seat by a locking means when it is at a predetermined position.