CA2752966C

CA2752966C - Locking system and switching apparatus for a locking system

Info

Publication number: CA2752966C
Application number: CA2752966A
Authority: CA
Inventors: Klaus Wolf; Markus Effinger; Stephan Kaps
Original assignee: Liebherr Aerospace Lindenberg GmbH
Current assignee: Liebherr Aerospace Lindenberg GmbH
Priority date: 2010-09-28
Filing date: 2011-09-22
Publication date: 2018-06-12
Anticipated expiration: 2031-09-22
Also published as: EP2433865A2; EP2433865B1; CN102417033B; ES2563778T3; DE102010046735A1; CA2752966A1; BRPI1106251A2; BRPI1106251B1; EP2433865A3; CN102417033A

Abstract

The present invention relates to a locking system, in particular a locking system for an aircraft, having at least one locking means which can be moved into at least one first position and into at least one second position, with the locking system having at least one switching apparatus by means of which the achieving of a defined end position of the locking means can be ensured and/or the locking system can be monitored.

Description

- -LOCKING SYSTEM AND SWITCHING APPARATUS
FOR A LOCKING SYSTEM
The present invention relates to a locking system, in particular a locking system for an aircraft, as well as to a switching apparatus for a locking system.
Modern aircraft today have predominantly hydraulic retractable landing gear.
To ensure their airworthiness, in particular in high-speed flight, it is necessary to be able to retract the landing gear systems of these aircraft reliably in operation, to be able to hold them and, as required, for example on a landing procedure, to be able to lower them again just as reliably.
The secure holding has previously been realized by locking systems which are mechanically connected to the structure of the aircraft and establish a shape-matched connection to the landing gear system in the retracted state thereof.
Only as part of an externally activated hook opening movement is the landing gear system released in a form-locked manner and is lowered either hydraulically or by the effect of gravity. The external activation of the hook opening movement is today achieved, due to the relatively high reliability demands for such systems, primarily by a hydraulically actuated piston and secondarily by a mechanical control wire actuation or by an electromechanical actuation unit.
The control wires of such mechanical actuation units frequently have to be guided through the fuselage of the aircraft via pressure zones or temperature zones, pulley blocks, guides and distributors. The complex assembly, intensive servicing and the varying wire tension due to different material properties in the system are disadvantageous in this respect. Within the course of an externally activated hook opening movement, the landing gear can be released in a shape matching manner with such systems. The hook opening movement can inter alia be mechanically activated by a control wire. The control wires in this respect have to be guided over a

- 2 -plurality of pulley blocks and deflection guides, which is very complex and also prone to error.
Locking systems having electromechanical actuation units are furthermore known from WO 2005/005252 Al. They are realized by means of an electromagnetic coil or an electric motor having a spindle or the like. It is disadvantageous in this respect that they cannot always be returned to the starting state by a simple switching off of the energy supply or are not capable of a reset/restart in any desired state.
Normally, corresponding electronics are required for this purpose.
A locking system is furthermore known from DE 10 2007 032 779 Al having redundant drive apparatus, with a first drive apparatus having an electromechanical drive unit and a transmission and a second drive apparatus being a hydraulically actuated drive apparatus. This locking system has a freewheel clutch to be able to restore the locking system to a defined end position.
SUMMARY OF INVENTION
It is therefore the object of the present invention to further develop a locking system of the initially named kind in an advantageous manner, in particular such that it preferably has a simple structure and in particular no additional electronics are required in the device and further preferably that any dead centers of the locking system are overcome and the locking system can always be restored to an end position.
In accordance with one aspect of the present invention, there is provided a locking system having: a) at least one locking means that is movable into: i) at least one first position; and ii) at least one second position; and b) at least one switching apparatus for i) achieving a defined end position of the locking means, ii) monitoring the locking system, or iii) a combination thereof; wherein: the switching apparatus includes at

- 3 -least one first power supply line and at least one second power supply line that are connected in parallel and that each independently supplies power to at least one drive of the locking system; and at least one of: a limit switch means is arranged in the first power supply line, such that the limit switch means either interrupts, closes, or a combination thereof, power supplied via the first power supply line to the at least one drive; and a further switching means is arranged in the second power supply line, such that the further switching means either interrupts, closes, or a combination thereof, power supplied via the second power supply line to the at least one drive.
In accordance with another aspect of the present invention, there is provided a switching apparatus for a locking system having at least one locking means that is movable into: i) at least one first position; and ii) at least one second position;
wherein: the switching apparatus includes at least one first power supply line and at least one second power supply line that are connected in parallel and that each independently supplies power to at least one drive of the locking system; and at least one of: a limit switch means is arranged in the first power supply line, such that the limit switch means either interrupts, closes, or a combination thereof, power supplied via the first power supply line to the at least one drive; and a further switching means is arranged in the second power supply line, such that the further switching means either interrupts, closes, or a combination thereof, power supplied via the second power supply line to the at least one drive.
Provision is thereby made that a locking system, in particular a locking system for an aircraft, is provided with at least one locking means which can be moved into at least one first position and into at least one second position, with the locking system having at least one switching apparatus by means of which the achieving of a defined end position of the locking means can be ensured and/or the locking system can be monitored.

- 3a -The advantage thereby results that the locking system can always be restored into an end position. Such an end position is in particular the position in which the locking system locks. For reasons of safety, the locking system is advantageously formed so that a secure locking is ensured without actuating the locking means in flight. In such an embodiment, it is expedient to design the locking system such that the reaching of the position in which the locking system locks is always ensured and effected by means of the switching apparatus.
It is, however, also conceivable that it is the position in which the locking system is unlocked. This can be provided alternatively or additionally.
The locking means can be a hook or can comprise a hook which can e.g. effect a locking of landing gear or of a door of an aircraft in the first position and which releases the landing gear or the door in the second position. Such locking systems are also called uplock systems or briefly uplocks.
It is furthermore conceivable that the locking means engages into a further locking means for the purpose of locking in a first position and the locking means can be released by the further locking means for the purpose of unlocking in a second position and that the locking system has at least one eccentric means, in particular

- 4 -a cam disk, with the locking means being able to be moved into the first and/or second position by means of the eccentric means.
The eccentric means can be monitorable by means of the switching apparatus.
The further locking means can, for example, be an engagement device or a pin which is arranged at the landing gear or at the door of the aircraft and in which the locking means of the locking system can engage. Provision can preferably be made that the locking means engages in a shape-matching manner or at least partially in a shape-matching manner into the further locking means in the first position.
The first position is, for example, the position which the locking system adopts in flight operation and the second position is the position which is adopted in the approach for a landing, on the ground and on the start.
It is furthermore possible that the switching apparatus has at least one limit switch means which can be switched in direct and/or indirect dependence on the position of the locking Means and/or of the eccentric means, with the limit switch means preferably being a microswitch and/or comprising a nnicroswitch. In this connection, it is conceivable to link positions of the locking means and/or eccentric means with switching states of the limit switch means, with such positions of the locking means and/or of the eccentric means being positions, for example, which correspond to a dead center. Dead centers are, for example, in this respect positions between the first and second positions or between the completely unlocked and locked positions in which the locking means and/or the eccentric means are located in an equilibrium position and would remain stationary without a further drive or impulse. A
departure from this equilibrium position or an overcoming of this dead center can be made possible and also ensured by a corresponding switching of the limit switch means.
Provision is preferably Made that the locking system in accordance with the invention does not have any dead center since preferably no mechanical restoration means such as a spring is present. In this respect the term "dead center" used is preferably to be understood in the sense of a non-defined position.

- 5 -Provision can furthermore be made that at least one mechanical element is provided which is movable, in particular rotatable, in direct and/or indirect dependence on the position of the locking means and/or of the eccentric means and by means of which the limit switch means can be actuated, with the mechanical element preferably being and/or comprising at least one cam plate. The limit switch means can be actuated by the mechanical element, for example in dependence on the position of the locking means and/or of the eccentric means, with the mechanical element for this purpose advantageously being connected directly and/or indirectly to the locking means and/or to the eccentric means and/or being arranged thereat. It is in particular conceivable in this connection that the eccentric means is arranged on the same axis as the mechanical element which is preferably a cam plate. The mechanical element can, for example, trigger or switch the limit switch means via an actuation lever.
It is furthermore conceivable that the switching apparatus includes at least one first power supply line and at least one second power supply line which are connected in parallel and by means of which at least one drive of the locking system can in each case be supplied with power independently of one another. The drive can advantageously be supplied via the power supply lines arranged in parallel, with the supply via one of the two power supply lines already being sufficient to actuate the drive.
It is moreover possible that the limit switch means is arranged in a power supply line, preferably in a first power supply line, with the power supply for the drive via this power supply line being able to be interrupted and/or closed by means of the limit switch means and/or that a further switching means is provided in a power supply line, preferably in a second power supply line, with the power supply for the drive via this power supply line being able to be interrupted and/or closed by means of the further switching means. The advantage thereby results of being able to supply the drive with power via respective power supply lines. The advantage further results by a combination of the switch states of actuating the drive such that

- 6 -any non-defined position in the system is reliably overcome and thus a restoration into a defined end position can always be ensured.
Provision can furthermore be made that the further switch means is and/or comprises at least one relay, in particular is and/or comprises at least one time relay.
Provision can, for example, be made that it interrupts the power supply to the drive via the second supply line after the elapse of a preset and predefinable time period.
It is furthermore preferably possible that the limit switch means is switchable, in particular switchable by actuation by means of the mechanical element, so that power for the drive can be supplied by means of the first power supply line when the further switch means has already been switched such that the second power supply line is interrupted. In a case in which the second power supply line is already closed and the locking means and/or the eccentric means is/are, however, still located in a non-defined position, it can thus preferably be ensured that the drive is still supplied with power via the first power supply line so that the restoration into a defined end position can take place.
Provision can advantageously be made that the switching apparatus has at least one signal output means and/or is in communication with at least one signal output means by means of which at least one state, in particular a switching state of the switching apparatus, can be output and/or communicated. The signal output means can, for example, be an LED, a lamp in the cockpit or an electronic pulse which can be communicated to a central control and/or regulation unit.

- 7 -Further details and advantages of the invention will now be explained in more detail with reference to an embodiment shown in the drawing. There are shown:
Figure 1: a schematic front view of a locking system;
Figure 2: a schematic rear view of a locking system;
Figure 3: a detailed view of the locking system; and Figure 4: a schematic representation of the switching apparatus.
Figure 1 shows in a schematic front view a locking system 10 of an aircraft, here for landing gear of the aircraft, in particular of an airplane. Such a locking system 10 can also be used in a corresponding modification for locking a door locking unit of an aircraft. These locking systems 10 are also called an uplock 10.
For reasons of redundancy, two drives 20 and 30 are provided by means of which the locking system 10 can be actuated.
An electric drive 20 is thus provided as a first drive which can, for example, be a brush motor. This electric motor 20 is provided at the torque output side with a planetary transmission 40, for. example, and transmits the output torque, for _ example, via a worm gear 50 to an axle having a cam disk 60. The actuation lever 70 can be actuated by means of the cam disk 60, which is usually rotated counter-clockwise for actuation in accordance with the representation in Figure 1, such that the hook 80 is moved from the first position, the locked position, into a second position, the unlocked position. A rotation of the cam disk 60 clockwise is generally also possible and is also covered by the invention.
Independently of this, the actuation lever 70 can also be moved by a second drive 30, namely the hydraulic drive 30, and indeed likewise such that the hook 80 is

- 8 -moved from the first position, the locked position, into a second position, the unlocked position.
The use of two different drives, here an electric drive 20, on the one hand, and a hydraulic drive 30, on the other hand, increases the operating security since, for example on a failure of the electric drive 20, the locking system 10 can always still be actuated by means of the hydraulic drive 30. This naturally applies accordingly in the converse case.
Figure 2 shows in a schematic rear view the locking system 10 shown in Figure and explained in this connection. A cam plate 90 is provided on the rear side of the axle with the cam disk 60 and a lever 112 of the microswitch 130 can be actuated by it and thus the microswitch 130, which is a component of the circuit 100, can be switched on and off.
The arrangement of microswitch 130 and of the cam plate 90 of the locking system in accordance with Figures 1 and 2 is shown again in detail in Figure 3.
Figure 4 shows the basic design of the circuit 100:
The electric drive 20 in its starting position opens the limit switch 130, here shown in a possible embodiment as a microswitch 130, via a mechanical element 90, here as a possible embodiment with a cam plate 90, whereby the power supply to the motor 20 is interrupted.
If now a function check or an emergency unlocking of the landing gear not shown in any more detail is carried out, the switch Si is closed. The time relay 140 or the "time based relay" 140 is supplied with power via the switch Si and actuates its switch for a predefined time to supply the drive 20 with power. A first power supply circuit for the drive 20 is thus established via the first power supply line 110.

- 9 -The drive 20 actuates the unlocking mechanism and a mechanical element 90, here, for example, the cam plate 90, via the transmission(s) 40, 50 and the microswitch 130 is actuated via the groove of said cam plate. At a defined angle of rotation of the cam plate 90, the microswitch 130 closes and supplies the motor 20 with power in parallel with the time relay 140 via the second, parallel power supply line 120.
If the predefined time in the time relay 140 has elapsed, this interrupts the power supply 110 to the drive 20. If the drive 20 or the cam plate 90 is not located in its starting position in which the second power supply line 120 is interrupted via the microswitch 130, the parallel circuit remains closed via the second power supply line 120 and supplies the motor 20 with power for so long until it has turned into its starting position and is opened via the microswitch 130.
A malfunction of the electric drive 20, in particular also a malfunction of the microswitch 130, can be recognized very easily as a signal 150 for monitoring, e.g.
an LED 150 or a lamp 150 in the cockpit or an electric pulse 150. The signal can also be used for a display/function in the landing gear controller.
It is thereby controlled whether the motor 20 and the cam disk 60 are again in their starting position after a specific time. For example, for this purpose, the LED 150 or display or lamp 150 must be active. In combination with a control unit, differentiated reports can be displayed in the cockpit while taking account of the time and/or further sensors, e.g. proximity switches for actuating the states "Landing gear lowered and locked" or "Landing gear retracted and locked" and/or "Locking hook unlocked or locked".
A substantial further advantage of this relay is the error mode. On the failure of the limit switch 130, it has no effect on the lowering function of the landing gear or, for example, the opening of a door if it is a door locking system. The limit switch 130 is only needed to move the cam disk 60 back into the starting position. If this is not possible, in the next retraction procedure or in a door closing procedure, the locking

- 10 -system 10 would not lock under certain circumstances. This malfunction is, however, recognized at an early time by the monitoring function 150 so that a check can take place on the ground before the next start.

Claims

1. A locking system (10) having:
a) at least one locking means (80) that is movable into: i) at least one first position; and ii) at least one second position; and b) at least one switching apparatus (100) for i) achieving a defined end position of the locking means (80), ii) monitoring the locking system (10), or iii) a combination thereof;
wherein:
the switching apparatus (100) includes at least one first power supply line (120) and at least one second power supply line (110) that are connected in parallel and that each independently supplies power to at least one drive (20) of the locking system (10);
and at least one of:
a limit switch means (130) is arranged in the first power supply line (120), such that the limit switch means (130) either interrupts, closes, or a combination thereof, power supplied via the first power supply line (120) to the at least one drive (20); and a further switching means (140) is arranged in the second power supply line (110), such that the further switching means (140) either interrupts, closes, or a combination thereof, power supplied via the second power supply line (110) to the at least one drive (20).

2. The locking system (10) in accordance with claim 1, wherein the locking system (10) is for an aircraft.

3. The locking system (10) in accordance with claim 1 or 2, wherein;
the locking means (80) engages with a further locking means (70) for the purpose of locking in the first position and is released by the further locking means (70) for the purpose of unlocking in the second position; and the locking system (10) has at least one eccentric means (60) for moving the locking means (80) into at least one of the first and second positions.

4. The locking system (10) in accordance with claim 3, wherein the at least one eccentric means (60) is a cam disk.

5. The locking system (10) in accordance with claim 3 or 4, wherein the at least one eccentric means (60) is monitored by the switching apparatus (100).

6. The locking system (10) in accordance with any one of claims 3 to 5, wherein the limit switch means (130) is switchable in either direct dependence, indirect dependence, or a combination thereof, on at least one of: the position of the locking means (80) and a position of the eccentric means (60).

7. The locking system (10) in accordance with claim 6, wherein the limit switch means (130) either: is a microswitch; includes a microswitch, or is a combination thereof.

8. The locking system (10) in accordance with claim 6 or 7, further having at least one mechanical element (90) that is movable in direct dependence,indirect dependence, or a combination thereof, on at least one of: the position of the locking means (80) and the position of the eccentric means (60),wherein the at least one mechanical element (90) actuates the limit switch means (130).

9. The locking system (10) in accordance with claim 8, wherein the mechanical element (90) is at least one cam plate, comprises at least one cam plate, or is a combination thereof.

10.The locking system (10) in accordance with claim 8 or 9 wherein the at least one mechanical element (90) is rotatable.

11. The locking system (10) in accordance with any one of claims 1 to 10, wherein the further switch means (140) is at least one relay; comprises at least one relay; or is a combination thereof.

12. The locking system (10) of claim 11, wherein the at least one relay (140) is a time relay.

13. The locking system (10) in accordance with any one of claims 1 to 12, wherein the limit switch means (130) is switchable, such that if the further switch means (140) has been switched such that the second power supply line (110) is interrupted, power is supplied to the drive (20) by means of the first power supply line (120).

14. The locking system (10) in accordance with claim 13, wherein the limit switch means (130) is switchable by actuation of the mechanical element (90).

15. The locking system (10) in accordance with any one of claims 1 to 14, wherein the switching apparatus (100) has at least one signal output means (150), is in communication with the at least one signal output means (150), or a combination thereof, by means of which at least one state is at least one of output and communicated.

16. The locking system (10) in accordance with claim 15, wherein the at least one state is a switching state of the switching apparatus (100).

17.A switching apparatus (100) for a locking system (10) having at least one locking means (80) that is movable into: i) at least one first position; and ii) at least one second position; wherein:
the switching apparatus (100) includes at least one first power supply line (120) and at least one second power supply line (110) that are connected in parallel and that each independently supplies power to at least one drive (20) of the locking system (10);

and at least one of:
a limit switch means (130) is arranged in the first power supply line (120), such that the limit switch means (130) either interrupts, closes, or a combination thereof, power supplied via the first power supply line (120) to the at least one drive (20);
and a further switching means (140) is arranged in the second power supply line (110), such that the further switching means (140) either interrupts, closes, or a combination thereof, power supplied via the second power supply line (110) to the at least one drive (20).

18. The switching apparatus (100) in accordance with claim 17 for at least one of monitoring the locking system (10) and achieving a defined end position of the locking means (80).

19. The switching apparatus (100) in accordance with claim 17 or 18, wherein the limit switch means (130) is switchable in either direct dependence, indirect dependence, or a combination thereof, on at least one of: the position of the locking means (80) and a position of an eccentric means (60).

20. The switching apparatus (100) in accordance with claim 19, wherein the limit switch means (130) either is a microswitch; includes a microswitch, or is a combination thereof.

21. The switching apparatus (100) in accordance with any one of claims 17 to 20, wherein the further switch means (140) is at least one relay; comprises at least one relay; or is a combination thereof.

22. The switching apparatus (100) of claim 21, wherein the at least one relay (140) is a time relay.

23. The switching apparatus (100) in accordance with any one of claims 17 to 22, wherein the limit switch means (130) is switchable, such that if the further switch means (140) has been switched such that the second power supply line (110) is interrupted, power is supplied to the drive (20) by means of the first power supply line (120).

24.The switching apparatus (100) in accordance with any one of claims 17 to 23, wherein the switching apparatus (100) has at least one signal output means (150), is in communication with the at least one signal output means (150), or a combination thereof, by means of which at least one state is at least one of output and communicated.

25. The switching apparatus (100) in accordance with claim 24, wherein the at least one state is a switching state of the switching apparatus (100).