U.S. patent application number 13/585631 was filed with the patent office on 2014-02-20 for pivoting display device used in aircraft.
This patent application is currently assigned to AIRCRAFT CABIN SYSTEMS. The applicant listed for this patent is Hironori KATOH, Koji NAKAMURA, Yukio SUGIMOTO. Invention is credited to Hironori KATOH, Koji NAKAMURA, Yukio SUGIMOTO.
Application Number | 20140048673 13/585631 |
Document ID | / |
Family ID | 50099398 |
Filed Date | 2014-02-20 |
United States Patent
Application |
20140048673 |
Kind Code |
A1 |
SUGIMOTO; Yukio ; et
al. |
February 20, 2014 |
PIVOTING DISPLAY DEVICE USED IN AIRCRAFT
Abstract
A pivoting device especially useful in aircraft passenger cabins
that can pivot a monitor between stowed and open positions, the
pivoting device including a forward/reverse rotatable driving
motor. An electromagnetic brake holds the monitor in stowed and
opened positions A power unit powers the motor and the
electromagnetic brake. A controller controls the pivoting movement
of the monitor. The power unit includes a rectifier circuit that
transforms AC to a DC, a step-up circuit that steps up the
transformed voltage, a voltage regulator that adjusts the
transformed voltage to a prescribed DC voltage, and a retraction
power retention circuit including a capacitor. When no source
voltage is detected while the monitor is in its opened state, the
capacitor supplies the power to a voltage regulator of the power
circuit, deactivates the electromagnetic brake and reverse rotates
the motor to drive the monitor to its stowed position.
Inventors: |
SUGIMOTO; Yukio; (Redmond,
WA) ; KATOH; Hironori; (Redmond, WA) ;
NAKAMURA; Koji; (Redmond, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SUGIMOTO; Yukio
KATOH; Hironori
NAKAMURA; Koji |
Redmond
Redmond
Redmond |
WA
WA
WA |
US
US
US |
|
|
Assignee: |
AIRCRAFT CABIN SYSTEMS
Redmond
WA
|
Family ID: |
50099398 |
Appl. No.: |
13/585631 |
Filed: |
August 14, 2012 |
Current U.S.
Class: |
248/550 |
Current CPC
Class: |
F16M 11/10 20130101;
B64D 11/0015 20130101; F16M 11/18 20130101; F16M 13/02
20130101 |
Class at
Publication: |
248/550 |
International
Class: |
F16M 13/02 20060101
F16M013/02 |
Claims
1. A pivoting display device for use in moving a monitor between
stowed and open positions which device comprises: a monitor
configured to pivot around a shaft supported by bearings fixed to a
frame of the stowing location; a monitor pivoting device including
a forward/reverse rotatable motor that can drive the said monitor
in a first closing direction and in a second opening direction, and
a transmission mechanism that conveys a rotating force of the motor
to the monitor; an electromagnetic brake that is configured to be
activated at each position in the stowed state and the opened state
of the monitor to maintain these states but deactivated when the
monitor is in the process of being moved between its open and
stowed positions; a power unit that drives the said monitor and
also drives the said motor and the said electromagnetic brake; a
controller that controls the pivoting of the said monitor about
said shaft; the said power unit being a power circuit that outputs
the prescribed DC voltage, comprising a rectifier circuit that
transforms an input AC voltage to a DC voltage, a step-up circuit
that steps up the transformed DC voltage, and a voltage regulator
that adjusts the stepped up DC voltage; wherein said power unit is
further provided with a retraction power retention circuit that
stores the said stepped up DC current in the capacitor while the
source voltage is supplied and that supplies the power stored in
capacitors to the voltage regulator of the said power circuit when
there is no source voltage available; and wherein the said
controller, when under a power failure condition where no source
voltage is detected and detecting that the monitor is in its opened
state, deactivates the electromagnetic brake and reverse rotating
the motor to drive the monitor to its stowed state using the power
stored in the retraction power retention circuit.
2. The pivoting display device according to claim 1, wherein: the
controller is configured to determine whether power has failed and
to run an interrupt processing when it detects that no source
voltage has been available for a prescribed amount of time, and to
deactivate the electromagnetic brake to cause the motor to drive
the monitor to its stowed state using the power stored in the
retraction power retention circuit if it detects that the monitor
is in its opened state; and said controller is further configured
such that in a temporary power failure when source voltage is
restored before the said prescribed time elapses, the said
controller determines that no power failure has occurred and by
supplying the power stored in the retraction power retention
circuit of the said power unit, maintains its control according to
its normal processing procedure it followed before the momentary
power failure occurred without carrying out the interrupt
processing.
3. The pivoting display device according to claim 2, wherein: the
detection of whether the prescribed time has elapsed or not is done
based on the output of the delay circuit that delays the detection
of the power failure and that is used in the power failure
detection circuit.
4. The pivoting display device according to claim 2, wherein: the
detection of the controller to determine whether the prescribed
time has elapsed or not is done by inputting the result of the
power failure detection done by the power failure detection circuit
directly into the control circuit, using the counting function or
the delay circuit in the control circuit.
5. The pivoting display device according to claim 1, wherein: the
monitor pivoting device that conveys the rotating force of the
motor as the swinging force to open and close the monitor
comprises; a ball screw shaft to which the motor conveys its
rotating force via the reduction gear; a moving piece that includes
a nut fitted into this ball screw shaft and that transforms the
rotating force of the ball screw shaft into the linear moving
force; and the link mechanism that transforms the linear moving
force of the moving piece into the rotating force of the monitor
operates by linking its one link to the moving piece and another to
the monitor; whereby said device is capable of holding the stowed
state and the opened state of the monitor at both moving positions
of the moving piece by configuring so that the rotating force of
the motor is once transformed into a linear movement by the ball
screw shaft and then conveyed to the monitor as a swinging force
via a link mechanism and to detect the stowage position and the
display position of the monitor using position sensors provided in
both moving positions of the moving piece.
6. The pivoting display device according to claim 1, wherein: the
power unit is provided with a rectifier that transforms the input
AC voltage into the DC voltage, a switching circuit that transforms
this DC voltage into a high frequency pulse train and a current
distortion correction circuit that corrects the distortion of the
current; wherein said rectifier transforms the input AC voltage
into a DC voltage that is further transformed into a high frequency
pulse train and then stepping up this DC voltage into a high
voltage using it to charge capacitors of the retraction power
retention circuit; and is further capable of adjusting the said
stepped up high DC voltage or the voltage discharged from the
capacitor using a voltage regulator to attain a required and
prescribed DC voltage and also capable of outputting the said
required and prescribed DC voltage after correcting it as current
distortion caused by the fluctuation of the input voltage using the
current distortion correction circuit.
7. The pivoting display device according to claim 1, when employed
to move a monitor between stowed and open positions in a passenger
vehicle.
8. The pivoting device according to claim 1, wherein said passenger
vehicle is an aircraft.
9. The pivoting device according to claim 1, wherein said device is
fixed to Passenger Service Unit (PSU) rails attached under the
overhead baggage rack/compartment of an aircraft such that the
attached monitors can be swung open downwards to the display
position and can be stowed back after their use.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the improvement of a
pivoting display device that comprise a video monitor that is used
over the head of a passengers especially in aircraft and that can
pivot the monitor open from its stowage position to its display
position.
[0003] 2. Description of the Background Art
[0004] Many passenger aircraft are provided with video monitors for
every 2-3 rows of passenger seats to show and play movies,
information about the flight and other similar material to
passengers. These monitors are usually fixed to Passenger Service
Unit (PSU) rails attached under the overhead baggage
rack/compartment above the passenger seat. Said monitors are
attached so that they can be swung open downwards to the display
position and can be stowed back after their use. These devices are
also provided with an electric motor and a drive mechanism that
conveys the motor's rotating force. It is desirable that this
pivoting display device can retract its monitor into the stowage
position in case the power supply to the cabin fails for some
reason.
[0005] The Federal Aviation Administration (FAA) requires that all
monitors to be stowed into their stowing location to secure the
safety of passengers in case the power supply to the cabin
fails.
[0006] Several prior art pivoting display devices have been
disclosed, for example, in U.S. Pat. No. 5,096,271 (Portman, Mar.
17, 1992) and U.S. Pat. No. 5,467,106 (Salomon, Nov. 14, 1995),
display devices are configured to retract the monitor to the
stowage position using a spring mechanism in case the power supply
fails. For those using the spring mechanism, the spring usually
contracts when the monitor is driven to the display position thus
the energy accumulated in the spring is used as a driving force to
stow the monitor. The driving mechanism that conveys the rotating
force of the motor and that consists of a gear transmission
mechanism or a link mechanism etc. is arranged between the motor
and the monitor and conveys the swinging force to pivot the
monitor.
[0007] Other pivoting display devices are, as disclosed for
instance in U.S. Pat. No. 6,373,216 (Ho, Apr. 16, 2002), configured
to use the forward and reverse rotation of the motor to open and
close the monitor instead of using a spring mechanism when stowing
the monitor. This device uses capacitors as a power unit to reverse
rotate the motor in the direction of stowing the monitor. That is,
it charges the capacitor while the power is supplied and the
monitor is in its opened state and then drives the monitor in the
direction of stowing it by changing over the circuit with a relay
and by reverse rotating the motor using the power charged in the
capacitor.
[0008] Systems wherein stowage of the monitor in case of a power
failure is by using a spring mechanism need to accumulate a
decompression force in the spring when driving the monitor to its
open position. The motor used for this therefore carries a heavy
load, thus necessitating the use of a motor with a capacity enough
to carry this load. Their operational reliability when driven by
the motor is also prone to problems. The spring mechanism provides
a force urging stowing the monitor while the monitor is in its
opened state since it needs to rotate and stow the monitor by
itself in case of a power failure. When this occurs, the motor and
gear box have to disconnect from the spring mechanism which may
require a clutch, thereby further complicating the mechanism. The
monitor needs to be braked or locked by an urging force larger than
the urging force of the spring mechanism in the direction of
stowing the monitor so as to maintain its opened state against the
force urging stowage. Furthermore, a mechanical type device using
the spring mechanism to stow the monitor, especially the spring
mechanism carrying said constant load is prone to deterioration by
a secular change which results in problems in maintaining its
reliability.
SUMMARY OF THE INVENTION
[0009] The aim of the present invention is to meet the requirement
of the Federal Aviation Administration (FAA) and to provide a
pivoting display device for aircraft that is capable of securely
driving the monitor to the stowage position in case of a power
failure. Further aims of embodiments of the invention are to effect
such stowage without causing an aging as in mechanical type devices
and to improve the reliability of its operation by reducing the
load carried by the motor that drives the monitor open and close,
and at the same time be capable of efficiently charging and
discharging capacitors that are used as a power unit to supply the
power in case of a power failure. Use of the pivoting display
device of the present invention is not, however, confined to use in
aircraft and may find use in other environments, especially other
means of passenger transport including railroad cars and buses or
coaches equipped with monitors.
[0010] To provide a solution for the above FAA requirement, the
present invention provides an embodiment comprising a mechanism
configured so that a monitor capable of having a stowed state and
also an open state and which is movable between the stowed state
and the open state by being swung by a pivoting device of the
monitor that comprises a forward/reverse rotatable driving motor
and a transmission mechanism that conveys the motor's output. It is
also provided with an electromagnetic brake that is activated at
each position in the stowed state and the opened state of the
monitor and that maintain these states, a power unit that supplies
the power to the motor and the electromagnetic brake, and a
controller that controls the pivoting movement of the monitor. The
said power unit is a power circuit that outputs the prescribed DC
voltage, comprising a rectifier circuit that transforms an input AC
voltage to a DC voltage, a step-up circuit that steps up the
transformed DC voltage and a voltage regulator that adjusts the
transformed voltage to provide the prescribed DC voltage. The said
power unit is further provided with a retraction power retention
circuit that stores the said stepped up DC voltage in the capacitor
while the source voltage is supplied and that supplies the power
stored in the capacitor to the voltage regulator of the said power
supply circuit when there is no source voltage available. The said
controller, when it detects no source voltage while the monitor is
in its opened state, deactivates the electromagnetic brake and
reverse rotate the motor to drive the monitor to its stowed state
using the power stored in the retraction power retention
circuit.
[0011] In the present invention, the controller, when it detects
the opened state of the monitor, is capable of deactivating the
electromagnetic brake and reverse rotating the motor thereby
driving the monitor from its opened state to its stowed state even
when no power is supplied since it supplies the power stored in the
retraction power retention circuit while the power is failing
regardless of its control state. The load that drags against
driving the monitor to its stowed state is light because the
reverse rotation of the motor under the power failing condition
deactivates the electromagnetic brake that has been activated in
the opened state and the operation involves simply the transmission
mechanism. The voltage of the power supply used to charge
capacitors in the retraction power retention circuit is stepped up
when supplied and is capable of charging the capacitor efficiently.
It is also capable of efficiently outputting a high power that is
stored in the capacitor because the output voltage is adjusted down
to the required low voltage via the voltage regulator when
capacitors are discharged. This also ensures its reliability by
supporting the secure stowing operation of the monitor in case of a
power failure.
[0012] Accordingly, the present invention provides a pivoting
display device for use in moving a monitor such as those used in
aircraft between stowed and open positions which device
comprises:
[0013] a monitor configured to pivot around a shaft supported by
bearings fixed to a frame of the stowing location;
[0014] a monitor pivoting device including a forward/reverse
rotatable motor that can drive the said monitor in a first closing
direction and in a second opening direction, and a transmission
mechanism that conveys a rotating force of the motor to the
monitor;
[0015] an electromagnetic brake that is configured to be activated
at each position in the stowed state and the opened state of the
monitor to maintain these states but deactivated when the monitor
is in the process of being moved between its open and stowed
positions;
[0016] a power unit that drives the said monitor and also drives
the said motor and the said electromagnetic brake;
[0017] a controller that controls the pivoting of the said monitor
about said shaft;
[0018] the said power unit being a power circuit that outputs the
prescribed DC voltage, comprising a rectifier circuit that
transforms an input AC voltage to a DC voltage, a step-up circuit
that steps up the transformed DC voltage, and a voltage regulator
that adjusts the stepped up DC voltage;
[0019] wherein said power unit is further provided with a
retraction power retention circuit that stores the said stepped up
DC current in the capacitor while the source voltage is supplied
and that supplies the power stored in capacitors to the voltage
regulator of the said power circuit when there is no source voltage
available;
[0020] and wherein the said controller, when under a power failure
condition where no source voltage is detected and detecting that
the monitor is in its opened state, deactivates the electromagnetic
brake and reverse rotating the motor to drive the monitor to its
stowed state using the power stored in the retraction power
retention circuit.
[0021] In a preferred embodiment, the controller is configured to
determine whether power has failed and to run an interrupt
processing when it detects that no source voltage has been
available for a prescribed amount of time, and to deactivate the
electromagnetic brake to cause the motor to drive the monitor to
its stowed state using the power stored in the retraction power
retention circuit if it detects that the monitor is in its opened
state;
[0022] and said controller is further configured such that in a
temporary power failure when source voltage is restored before the
said prescribed time elapses, the said controller determines that
no power failure has occurred and by supplying the power stored in
the retraction power retention circuit of the said power unit,
maintains its control according to its normal processing procedure
it followed before the momentary power failure occurred without
carrying out the interrupt processing.
[0023] In one particular embodiment, the power unit is provided
with a rectifier that transforms the input AC voltage into the DC
voltage, a switching circuit that transforms this DC voltage into a
high frequency pulse train and a current distortion correction
circuit that corrects the distortion of the current;
[0024] wherein said rectifier transforms the input AC voltage into
a DC voltage that is further transformed into a high frequency
pulse train and then stepping up this DC voltage into a high
voltage using it to charge capacitors of the retraction power
retention circuit; and
[0025] is further capable of adjusting the said stepped up high DC
voltage or the voltage discharged from the capacitor using a
voltage regulator to attain a required and prescribed DC voltage
and also capable of outputting the said required and prescribed DC
voltage after correcting it as current distortion caused by the
fluctuation of the input voltage using the current distortion
correction circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a side view of the embodiment of the present
invention that is a pivoting display device for aircraft that shows
the stowed state of the monitor. Some part of the chassis plate
portion at hand is omitted;
[0027] FIG. 2 is a side view that shows the open state of the
monitor. The said part of the chassis plate portion at hand is
omitted;
[0028] FIG. 3 is a perspective view that shows the opened state of
the monitor at the display position. The said part of the chassis
plate portion at hand is omitted;
[0029] FIG. 4 is a perspective view that shows the stowed state of
the monitor. Some part of the chassis plate portion shown in FIG. 4
is further omitted;
[0030] FIG. 5 is a perspective view that shows the appearance of
the opened state of the monitor at the display state;
[0031] FIG. 6 is a circuit diagram that shows the said
embodiment;
[0032] FIG. 7 is a flowchart of the control processing of the said
embodiment while in its normal operation; and
[0033] FIG. 8 is a flowchart of an interrupt control processing of
the said embodiment when a power failure is detected.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Preferred embodiments of the present invention, that is, a
pivoting display device for use in aircraft will be described with
reference to the drawings.
[0035] In the embodiment shown in FIGS. 1 to 5, the pivoting
display device 1 is fixed to the PSU rail (not shown in figures)
under the baggage rack/compartment in the ceiling area of the cabin
of the aircraft. It is configured to enable a monitor 3 with a LCD
unit to pivot open to the display position. The monitor 3 is
supported by a bearing portion 4b that is attached and integrated
into a chassis plate 4a of a chassis 4 that compose the entire
device thereby enabling it to pivot around a shaft 3a. The chassis
4 serves also as a housing that composes the entire device. The
said chassis comprises a stowing portion 5a, and also a stowing
portion 5b which on its upper surface stows a motor 6, a gear
transmission mechanism and circuit parts etc. for swinging the
monitor 3. Here, in FIGS. 1 to 4, the chassis plate 4a covering the
side at hand of the chassis 4 is omitted and is shown by a dotted
line. FIG. 5 shows the appearance of the chassis plate 4a on the
side at hand. FIGS. 1 to 5 show only one side of the chassis plate
along with the bearing portion 4b that supports the shaft 3a of the
monitor 3 but the other side of the chassis plate 4a is provided
with another bearing facing 4b thereby enabling the stable swinging
of the monitor. The pivoting display device is also configured to
be fixed under the baggage rack/compartment 2 in the ceiling area
of the cabin by attaching a part of the chassis 4 (not shown in
figures) to the said PSU rail.
[0036] The pivoting display device 1, by swinging around shaft 3a
as shown in the side views of FIGS. 1 and 2, can be pivoted from
the stowed state in the stowing location 5a to the opened state at
the display position where passengers can watch and listen to its
programs.
[0037] The pivoting device of the monitor 3 is configured to convey
the rotating force of the motor 6 to monitor 3 via the rotation
transmission mechanism and the link mechanism. It specifically
include the reduction gear 7 at the output side of the motor 6, a
ball screw shaft 9 linked via a coupling 8 provided at the output
side of the reduction gear 7, a moving piece 10 that moves with the
ball-nut fitted to the ball screw shaft 9, a link 11 of which its
one side is linked to the moving piece 10 and an arm portion 12 of
the monitor 3 where the other side of link 11 is linked to. The
output shaft of the reduction gear 7 and the output shaft of the
coupling 8 are supported by a bearing 13. The ball screw shaft 9 is
supported by the bearing 13 and by the ball-nut portion of the
moving piece 10. The moving piece 10 and the link 11 are linked by
shaft 11a and the link 11 and the arm portion 12 of the monitor 3
are linked by shaft 11b. Each of them is linked so as to allow them
to rotate freely. Here, the transmission of the rotation is done
without any interference since the coupling 8 absorbs the
displacement between the output shaft of the reduction gear 7 and
the center of the ball screw shaft 9. The moving piece 10 can move
linearly along the axis line of the ball screw shaft 9 by the
rotation of the ball screw shaft 9. It is configured to reduce the
load on the motor 6 using balls fitted in between the ball-nut and
the ball screw shaft 9.
[0038] By this configuration, the rotation force of the motor 6 is
conveyed to the ball screw shaft 9 via the reduction gear 7
arranged along the coaxial direction of the shaft, then to the
coupling 8, and the ball screw shaft 9 moves the moving piece 10
along its axis line by rotating itself. This linear movement of the
moving piece 10 also moves one of the link shaft 11a of the link 11
along the axis line, said linear movement moving the other link
shaft (11b) of the link 11. Although the arm portion 12 of the
monitor 3 linked to the link shaft 11b moves in tandem with the
said linear movement of the shaft, the link shaft that is linked to
the said arm portion 12 makes an arc movement around the swing
shaft 3a of the monitor 3. The swinging and the said arc movement
of the arm portion 12 swings the monitor 3 that is integrated with
the arm portion 12 around the shaft 3a. Therefore, the rotation
force driven by the motor 6 is once transformed into a linear
movement, and then conveyed to the monitors 3 as a swinging force
which enables the monitor to pivot open and close around the shaft
3a. That is, the rotation force of the motor 6 is conveyed as the
swinging force to pivot the monitor 3 open and close thereby
forming a monitor pivoting device.
[0039] The pivoting device of the monitor 3 is also provided with
an electromagnetic brake 14 to hold the monitor firmly in each of
the opened and closed state of the monitor 3 which are the stowed
state in the stowing portion and the opened state at the display
position. This is done by activating the brake against the motor so
that the load such as its own weight will not be conveyed to the
rotor via the transmission mechanism thus rotating the rotor after
the motor 6 had driven the monitor to each position. Therefore, the
electromagnetic brake 14 is designed to stay activated in the
stowed state and also in the opened state of the monitor 6, but is
deactivated when the motor 6 needs to rotate thus reducing the
driving load of the motor 6.
[0040] The moving piece 10 moved by the ball screw shaft 9 is
fitted into a straight guide rail 15 provided at the bottom surface
of the stowing portion 5b of the chassis 4 so as to slide in the
linear motion along the guide rail 15. Moving piece 10 is provided
with a sensor plate 10a and the position of the moving piece 10 can
be detected by the position sensors 16a and 16b provided at the
stowing portion 5b of the chassis 4. Here, position sensors 16a and
16b that are placed to face the sensor plate 10a comprise of photo
sensors and are capable of detecting the sensor plate 10a when it
comes to each position. The position detection by these position
sensors 16a and 16b is for detecting each of the stop position of
the monitor 3 in the stowed state and in the opened state.
[0041] The sets of electrical parts 17 forming the power unit of
the electric circuit and the control circuit etc. described below
are mounted on the PC board 18 inside the stowing portion 5b of the
chassis 4 along with the aforementioned pivoting mechanism. The
stowing portion 5c partitioned by the plate 4c is also provided
with several capacitors 19a-19d that supply power in case of a
power failure. Each circuit laid out on the PC board 18 is
connected to the monitor 3 via a wiring 20a connected to the
connector mounted on the PC board 18, or to capacitors 19a-19d via
a wiring 20b. Although not shown in FIGS. 1 to 5, it is also
provided with an input connector to supply the power from the power
source of the aircraft into the present invention, that is, a
pivoting display device. It is also provided with wirings etc. that
are necessary for the operation of the entire device. In addition,
4d in these figures is an ornamental frame attached to the chassis
4 and is intended to improve the appearance of the penumbra of the
pivoting display device 1 being attached under the baggage
rack/compartment in the ceiling area of the cabin.
[0042] The circuit diagram shown in the FIG. 6 will be described
next. In this description reference is made to typical voltages and
frequencies presently used in aircraft. It will be recognized that
in some situations, these voltages and frequencies may change. In
such situations, the voltages and frequencies hereinafter mentioned
should be adjusted appropriately.
[0043] This circuit diagram covers the power unit, the power supply
to the monitor 3, the driving circuit that opens and closes the
monitor 3 and the controller for its power supply and operation,
and does not cover the circuit of the monitor 3.
[0044] The AC voltage from the power source of the aircraft,
typically of AC115V/400 Hz, is normally supplied to the input
connector portion and is input to the normal power circuit 54 of
the power block 53 via the input voltage detection circuit 52. In
this power circuit 54, the AC voltage is first transformed into the
DC voltage by the first rectifier 55, then transformed into a high
frequency pulse train by a switching process using the next
switching circuit 56, then stepped up using the next transformer 57
and thereafter, further transformed, typically to DC220V, using the
second rectifier 58 and supplied to the next current and voltage
regulator circuit 59 via the smoothing capacitor C4. This current
and voltage regulator circuit 59 outputs the necessary DC voltage.
Video monitor rest circuits typically operate at 12 V and so this
is the normal output from regulator circuit 59. However, other
outputs in the range 3.3V-20 V may be used in some cases. This
output is effected using a voltage regulator 59a that has a
function of transforming the stepped up voltage down to the output
voltage of, say, DC12V and a current distortion correction circuit
59b that has a function of correcting the current distortion. Here,
this configuration of the power unit 54 composing the switching
circuit 56 and the current distortion correction circuit 59b is
intended to meet the requirement of the RTCA/DO-160F standards
concerning the airborne electronic device of the aircraft. That is,
with the said circuit configuration, it is capable of absorbing or
reducing the distortion caused to the input current of the AC power
source by the electric current consumed by the circuit even if that
happens.
[0045] A high voltage, typically DC220V, to provide retraction
power is also supplied to retention circuit 60 after being stepped
up by the transformer 57 and rectified by the second rectifier 58.
This retraction power retention circuit 60 is provided with
capacitors C1, C2, and C3 that correspond to aforementioned
capacitors 19a, 19b and 19c, resistors R1, R2 and R3 that are
connected in series to control the rush current to said capacitors
C1, C2 and C3 and diodes D1, D2 and D3 that are connected parallel
to resistors R1, R2 and R3 to bypass these resistors R1, R2 and R3
when capacitors discharge the electricity. Capacitors C1, C2, and
C3 are connected parallel, and each of them are charged to store
the power. Here, it is capable of efficiently storing a high power
into small size capacitors by charging capacitors C1, C2, and C3 of
the retraction power retention circuit 60 with the high voltage
(such as DC220V). The retraction power retention circuit 60 is
charged while the source voltage is supplied to the input connector
portion 51, and discharges the power to the current and voltage
regulator circuit 59 via the smoothing capacitor C4 when the power
supply to the input connector portion 51 stopped. The retraction
power retention circuit 60 is capable of discharging the
electricity as long as it can maintain the prescribed output
voltage, typically of DC12V, of the current and voltage regulator
circuit 59. It restarts charging when the source voltage begins to
be supplied to the input connector portion 51.
[0046] In FIG. 6 controller 61 comprises power supply circuit
supplied with the voltage of DC12V from the output side of the
current and voltage regulator circuit of the aforementioned power
supply circuit 54, a control circuit 63 that controls the power
supplied from a power supply circuit 62 into each of the controlled
portions and a delay circuit 64 that counts the prescribed amount
of time (for example, 250 mSec) when the aforementioned input
voltage detection circuit 52 detects no source voltage. Power
interruptions of up to 200 mSec may occur for example when
switching power sources from a ground connection to power from an
auxiliary power unit or power generated by the engines and so
prescribed periods different from 250 mSec may be set if desired.
The control circuit 63 is also capable of detecting when no source
voltage is available by the input voltage detection circuit 52 via
the delay circuit 64, is capable of detecting the stowed state and
the opened state of the monitor 3 by position sensors 16a and 16b,
and is capable of detecting that the monitor 3 is turned on when
detecting the video signal using its video signal detection circuit
65. The control circuit 63 controls the pivoting of the monitor 3
by controlling the motor 6 and the electromagnetic brake 14 based
on these detected result. The power supply circuit 62 controlled by
the control circuit 63 supplies the required voltage (such as
DC12V) to the motor 6, the electromagnetic brake 14 and also, via
the output connector 67, to the monitor 3. Here, the power is
supplied to the motor 6 via a change-over circuit 66 for changing
over the forward and the reverse rotation of the motor. The
change-over circuit 66 is provided with a pair of change-over
switches that change over the polarity of the DC power source. The
control circuit 63 controls this changeover. The power supply
circuit 62 is constantly supplying the source voltage to the
control circuit 63. Here, the motor 6 and the electromagnetic brake
14 are connected parallel to a power supply connector of the power
supply circuit 62 so the power is supplied simultaneously.
Therefore, the electromagnetic brake 14, while in a motor driven
operation, is also supplied with and deactivated by the power
supplied from the power source along with the motor 6 so as not to
interfere with the rotation of the motor 6 when it is running.
[0047] Additionally, another way is to deactivate the
electromagnetic brake 14 before the motor 6 starts running and to
reactivate it after the motor 6 stops running by independently
supplying the power to the motor 6 and to the electromagnetic brake
14. Although the power failure detection by the control circuit 63
is explained above to be delayed by the delay circuit 64 for a
prescribed amount of time, another way is to input the detection
result of the power failure into the control circuit 63 directly
without supplying via the delay circuit 64 using instead a delaying
function (a delay circuit or a counting function) inside the
control circuit 63.
[0048] The flow of the control processing by the controller 61 will
be described next based on FIG. 7 that shows the flowchart of the
normal operation and FIG. 8 showing the flowchart of the interrupt
processing when no source voltage can be detected (power
failure).
[0049] In the normal operation in FIG. 7, after initialized in step
S1, the monitor 3 starts opening and heading for its display
position so as to start showing the program when the video signal
detection circuit 65 detects the video signal in step S2. First,
the electromagnetic brake 14 is deactivated in step S3 and the
motor 6 starts running in step S4 in the direction of swinging the
monitor 3 open. The positions sensor 16a, at that time, has already
detected the stowed state of the monitor 3 by sensing the sensor
plate 10a on its side. With the change-over circuit 66 changed over
to control the drive of the motor in the forward direction, the
motor 6 in step S4 continues to drive the monitor 3 until it
reaches the display position and the position sensor 16b detects
that state in step S5. The motor 6 stops running in step S6 when
the opened state of the monitor is detected. Then the
electromagnetic brake 14 is activated and the opened state of the
monitor 3 is maintained in step S7. The opened state of the monitor
3 is maintained until the video signal ceases to be detected in
step S8. When the video signal ceases to be detected in step S8, it
is decided that the monitor 3 has finished showing the program, so
the electromagnetic brake 14 is deactivated in step S9 and the
motor 6 starts swinging in the direction of stowing (reverse
direction) to stow the monitor 3 in step S10. The changeover of the
direction then is done by the change-over circuit 66 controlled by
the control circuit 63. The rotation of the motor 6 in the
direction of stowing the monitor 3 is maintained until the monitor
3 reaches its stowage position and the position sensor 16a detects
this state in step 11. The controller proceeds to step S12 and
stops the motor 6 when the stowage position is detected. The
electromagnetic brake 14 is activated in step S13 to maintain the
stowed state of the monitor 3 then going back to step S2 to standby
until the video signal is detected again.
[0050] Then, the flow of the control operation of the interrupt
processing when the power source of the aircraft fails for some
reason and when this failure is detected, will be described based
on FIG. 8.
[0051] In step S14, when a power failure is detected by the input
voltage detection circuit 52, the delay function of the delay
circuit 64 or the control circuit 63 checks whether a certain
amount of time (for example, 250 mSec) has elapsed and keeps on
returning until this certain amount of time elapses. In other
words, in a momentary power failure when the power is restored
shortly and before a certain amount of time elapses, the device
maintains its control according to its normal processing procedure
without carrying out the interrupt processing that begins from step
S15. The operation of the display device itself is not affected by
the momentary power failure since the power supply during the
momentary power failure is done by the power stored in capacitors
C1, C2 and C3 of the retraction power retention circuit 60. When a
certain amount of elapse time is detected in step S14, the
controller decides that it is in a state of power failure and
proceeds to Step S15 and takes over the control to stop the power
supply to the output terminal 67. Then the power supply to the
monitor unit is stopped. And, the controller decides whether the
monitor 3 is in its opened state or not in step S16, and decides
whether it is in a stowed state or not if not in its opened state
in step S17. Each state is decided by the position detected by
position sensors 16a and 16b. If the opened state of the monitor 3
is detected in step S16 by the position sensor 16b, the monitor 3
is controlled to swing in the stowing direction in which case it is
driven by the power stored in capacitors C1, C2 and C3 of the
retraction power retention circuit 60. In that case, the controller
first deactivates the electromagnetic brake 14 in step S18, and
then, in step S19, reverse rotates the motor 6 and swings the
monitor 3 to its stowing direction by controlling the change-over
circuit 66 to reverse its polarity. This reverse rotation of the
motor 6 is maintained until the stowed state of the monitor 3 is
detected by the position sensor 16a in step S20. When the stowed
state is detected in step S20, the controller stops the motor 6 in
step S21 and also activates the electromagnetic brake 14 in next
step S22 to hold the stowed state of the monitor 3. If the stowed
state is not detected in step S17 above, the controller decides
that the monitor 3 is being driven open or close, thus proceeding
to step S19. Here, the operation of the monitor 3 is maintained if
the pivoting movement is in the stowing direction, but the
controller reverse rotates the motor 6 to swing the monitor 3 in
its stowing direction by controlling the change-over circuit 66 in
step S19 to reverse its polarity even if the pivoting movement of
the monitor 3 is in its opening direction. In addition, if the
stowed state is detected in step S17, the controller proceeds to
step S21 taking the case where the monitor has reached its stowed
state immediately before into consideration. Then, following the
state in step S22 where the stowed state of the monitor 3 is
complete, it maintains this processing until it detects the power
recovery using the input voltage detection circuit 52, and then
ends the interrupt processing and returns to the start when the
power recovery is detected in step S23.
[0052] As described above, the embodiment of the pivoting display
device for use in aircraft of the present invention is configured
so that the monitor 3 capable of having a stowed state and an
opened state can be swung using a pivoting device of the monitor 3
that comprise a forward/reverse rotatable driving motor 6 and a
transmission mechanism that conveys the motor's output. It is also
provided with an electromagnetic brake 14 that is activated at each
position of monitor 3 in its stowed state and its opened state and
that maintains these states, a power unit 53 that supplies the
power to the motor 6 and the electromagnetic brake 14, and a
controller 61 that controls the pivoting movement of the monitor 3.
The power unit 53 is a power circuit 54 that outputs the prescribed
DC voltage, comprising a rectifier circuit 55 that transforms an
input AC voltage to a DC voltage, a step-up circuit 57 that steps
the transformed DC voltage up and a voltage regulator 59a that
adjusts the transformed voltage to provide the required DC voltage.
The said power unit is further provided with a retraction power
retention circuit 60 that stores the said stepped up DC current in
capacitors C1, C2 and C3 while the source voltage is supplied and
that supply the power stored in capacitors to the voltage regulator
59a of the said power circuit when there is no source voltage
available. The said controller 53, when it detects that no source
voltage is available while the monitor 3 is in its opened state, is
capable of deactivating the electromagnetic brake 14 and reverse
rotating the motor 6 to drive the monitor 3 to its stowed state
using the power stored in the retraction power retention circuit
60.
[0053] In this embodiment, the controller, when it detects the
opened state of the monitor, is capable of deactivating the
electromagnetic brake and reverse rotating the motor thereby
driving the monitor from its opened state to its stowage position
even when no power is supplied since it supplies the power stored
in the retraction power retention circuit while the power is
failing regardless of its control state. Capacitors can be charged
efficiently because the voltage of the power supply is stepped up
when charging capacitors in the retraction power retention circuit.
It is also capable of efficiently outputting a high power that is
being stored in the capacitor because the power output is done by
adjusting it down to the required low voltage via the voltage
regulator when capacitors are discharged. This also ensures its
reliability by supporting the secure stowing operation of the
monitor when the power failed. Furthermore, a motor and an
electromagnetic brake of low energy consumption type may be used
because they do not carry a load as heavy as those that stow the
monitor in case of power failures using the urging force of the
spring mechanism.
[0054] Therefore, the present invention is capable of driving the
monitor to its stowed state using the power stored in the
retraction power retention circuit of the power unit even when the
power failure occurs inside the aircraft for some reason, and thus
capable of securing the safety of the passengers required by the
Federal Aviation Administration (FAA). It is also capable of
securely driving the monitor to the stowage position in case of a
power failure without aging as in mechanical type devices and that
is capable of improving the reliability of its operation by
reducing the load on the motor that drives the monitor open and
close, and at the same time capable of efficiently charging and
discharging capacitors that are used as a power unit to supply the
power in case of a power failure.
[0055] The present invention providing a pivoting display device
suitable for use in aircraft, configures the control by the
controller as follows.
[0056] The controller determines that the power failed and runs an
interrupt processing when it detects that no source voltage has
been available for the prescribed amount of time and deactivates
the electromagnetic brake and drives the said motor to drive the
monitor to its stowed state using the power stored in the
retraction power retention circuit when it detects that the said
monitor is in its opened state. In a brief power interruption due
to a temporary power failure, for example of less than 200 mSec,
when the source voltage is restored quickly and before the said
prescribed time elapses, the controller determines that no power
failure has occurred and by supplying the power stored in the
retraction power retention circuit of the said power unit,
maintains its control according to its normal processing procedure
it followed before the temporary power failure occurred without
carrying out an interrupt processing. Therefore, in the present
invention, it is capable of handling the power failure and the
temporary power failure distinctively and maintaining a normal
operation using the power stored in the retraction power retention
circuit without stowing the monitor in case of a momentary power
failure that does not hinder the operation of electronic
devices.
[0057] In this case, the detection to decide whether the prescribed
time has elapsed or not may be done either based on the output of
the delay circuit that delays the detection of the power failure by
the power failure detection circuit or by inputting the result of
the power failure detection of the power failure detection circuit
directly into the control circuit using the counting function or
the delay circuit inside the control circuit.
[0058] In the present invention, the monitor pivoting device that
conveys the rotating force of the motor as a swinging force to
pivot the monitor open and close is configured as below.
[0059] That is, it is provided with a ball screw shaft to which the
rotating force of the motor is conveyed via the reduction gear, a
moving piece that includes a nut fitted into this ball screw shaft
and that transforms the rotating force of the ball screw shaft into
a linear moving force and a link mechanism that transforms the
linear moving force of the moving piece into a rotating force of
the monitor by linking its one link to the moving piece and another
to the monitor. It is capable of using the ball screw shaft to once
transform the rotating force of the motor into a linear movement
and then conveying it to the monitor as a swinging force via a link
mechanism and also of holding the stowed state and the opened state
of the monitor at both moving positions of the moving piece. It is
also capable of detecting the stowage position and the display
position of the monitor using position sensors provided in both
moving positions of the moving piece.
[0060] This configuration is simpler than that of display pivoting
devices that drive the monitor open and close using a combining
structure that combines an operation using a ball screw shaft and a
mechanical stowing of the monitor in case of a power failure using
a coil spring, such as, for instance, one disclosed in the (JP
Bulletin 2009-166582). Thus, in the present invention, in contrast
to the prior literature driven by the ball screw shaft, the load
that drags against driving the monitor to its stowed state when the
power failed is light because it deactivates the electromagnetic
brake that has been active in the opened state and the operation
involves simply the ball screw shaft and the link mechanism.
[0061] In the pivoting display device of the present invention, the
power unit that supplies the power for the operation of the
monitor, the driving of the motor, the activation of the
electromagnetic brake, and the controller is configured as
follows.
[0062] That is, the power unit is provided with a rectifier that
transforms the input AC voltage into the DC voltage, thereafter a
switching circuit that transforms this DC voltage into a high
frequency pulse train and a current distortion correction circuit
that corrects the distortion of the current. Therefore, it
rectifies and transforms the input AC voltage into a DC voltage
that is further transformed into a high frequency pulse train and
then stepping up this DC voltage into a high voltage using it to
charge capacitors of the retraction power retention circuit. It is
further capable of adjusting the said stepped up high DC voltage or
the voltage discharged from the capacitor using a voltage regulator
to attain a required and prescribed DC voltage and also capable of
outputting the power after correcting the current distortion caused
by the fluctuation of the input voltage using the current
distortion correction circuit.
[0063] With the said configuration, it is capable of meeting the
requirement of the RTCA/DO-160F standards concerning the airborne
electronic device of the aircraft by absorbing or reducing the
distortion of the input current of the AC power source caused by
the electric current consumed by the circuit even if that happens
and is capable of keeping control of the current distortion of the
AC input as required for airborne electronic devices.
[0064] Additionally, in the present invention, the numbers of
capacitors that compose the retraction power retention circuit or
the voltage stepped up to charge these capacitors have no
particular limit so long as they are capable of responding to the
momentary power failures and are capable of storing the power to
securely drive the monitor to its stowed state under the power
failing conditions.
* * * * *