Patent Description:
Actuatable doors and, in particular, fuselage doors in aircrafts usually fulfill the following major functions: they close the aircraft in operation for maintaining a required internal pressure therein, they allow external access to the aircraft on the ground, and they enable safe and quick evacuation of the aircraft in case of an emergency. Therefore, a high level of functional reliability has to be ensured, and robust and safe actuating systems are required for reliably and safely closing the actuatable doors in operation, but also for fulfilling all relevant requirements defined by the competent authorities.

Airworthiness requirements have been defined for fuselage doors in aircrafts with the intention of ensuring multiple layers of protection. These protection layers typically include a latching system, a locking system, indication systems, and pressure prevention means.

As an example, section <NUM> of the European Union Aviation Safety Agency's "Certification Specifications and Acceptable Means of Compliance for Large Aeroplanes" (EASA CS <NUM>) defines requirements for fuselage doors of aircrafts in general.

More specifically, according to EASA CS <NUM>(d)(<NUM>) such actuating systems require latches and corresponding latching devices that must be designed so that, under all aircraft flight and ground loading conditions, there is no force or torque tending to unlatch the latches in the closed state of the actuatable door. In addition, the latching devices must include means for securing the latches in an associated latched state. The securing of the latches and the latches must be independent from the lock if the latches are latched.

Furthermore, according to EASA CS <NUM>(d)(<NUM>), each door with an inward opening movement, and for which unlatching could result in hazard, must have a locking means to prevent the latches from becoming disengaged.

The document <CIT> describes a conventional actuating system for an actuatable door that fulfills these requirements and comprises a plurality of latching devices, each being provided with an associated latching hook that is adapted for latching the actuatable door in a closed position. Each latching hook is securable in its latched state by means of a separate rotatable securing device, which is implemented as a securing cam.

More specifically, each latching hook is pivotally mounted to a first pivot bearing and connected to a pivotable mechanical transmission element via a coupling link. The latter is implemented as a first coupling rod and on the one hand pivotally mounted to the latching hook by means of a second pivot bearing and on the other hand to the pivotable mechanical transmission element by means of a third pivot bearing. The pivotable mechanical transmission element is implemented as a bell crank, which is pivotable around an associated bell crank bolt defining a fourth pivot bearing. The bell crank is further coupled to a latch lever by means of a coupling link, which is implemented as a second coupling rod. The latter is on the one hand pivotally mounted to the bell crank by means of a fifth pivot bearing and on the other hand to the latch lever by means of a sixth pivot bearing. The latch lever is coupled to a rotatable latching shaft, which defines a seventh bearing of the conventional actuating system.

However, the above described conventional actuating system is comparatively complicated and expensive, as each latching device thereof, i.e. without the separate rotatable locking device, comprises multiple constituent components including five moving parts in row with seven bearings involved. Consequently, this conventional actuating system is comparatively heavy and space consuming and manufacturing and assembly thereof is rather complicated due to the great number of components and tolerances.

Other illustrative mechanisms for closing aircraft doors are described in documents <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

More particularly, <CIT> describes a latch lock mechanism for opening and closing a translating motion-type aircraft door. The latch lock mechanism includes a latch shaft that is mounted to the door by a set of follower bearings that are axially offset from the shaft. The shaft is rotated by a lift lock mechanism that includes a lift lock cam and a cam follower that tracks the cam, and a door drive linkage that is attached to the cam follower for rotating the latch shaft. The lift lock cam is rotated by a handle shaft that is actuated by a handle. When the handle is rotated, the lift lock cam is similarly rotated so as to cause the upward movement of the door drive linkage in the rotation of the latch shaft. The follower bearings rotate about the latch shaft so as to lift the latch shaft and the door upwards so as to allow the door to clear fixed fuselage stop tabs so that the door can be moved to an open position. An auxiliary latch-hold up cam mechanism forces the door open in the event the latch shaft and associated components fail. A pressure vent door is selectively opened by an associated opener assembly connected to the handle shaft. In the event an attempt is made to open the door while the aircraft is in flight, the pressure vent door opener assembly locks out so as to inhibit movement of the handle shaft that would actuate the latch shaft and open the door. The documents <CIT>, <CIT> and <CIT> were cited.

Of these, according to its abstract <CIT> discloses a latch device of a covering cap. The latch device comprises a lock shaft, at least one latch shaft, at least one latch unlocking mechanism and at least one latch mechanism; the lock shaft and the latch shafts are separately arranged on the covering cap; each of the latch unlocking mechanisms comprises a crankshaft arranged on the lock shaft, a connecting rod, one end of which is hinged to the crankshaft while the other end of which is rotatably connected to the latch shaft, and a latch arranged on the each of the latch shafts and a latch slot matched with the latch; the latch slot is formed in a cap frame matched with the covering cap; and each latch lock mechanism comprises a lock arranged on the lock shaft and a latch lock arranged on each latch shaft.

However, in many of the above-referenced state-of-the-art designs, each of the latching hooks is installed on a separate fixed bolt, which serves as rotation axis for the latching hooks. Each latching hook is driven by the latching shaft via its own drive mechanism. In addition, each drive mechanism serves as latch securing means for its latching hook. Each latching hook is locked by an individual locking device, mounted on the locking shaft. The locking device is locking the latching hook and monitoring the latched position of the latch. Thus, the above-mentioned state-of-the-art solutions have many components which leads to heavy, difficult to assemble, and comparatively expensive to manufacture solutions.

It is, therefore, an objective to provide a new actuating system for an actuatable door that is suitable to overcome the above-described drawbacks. In particular, the new actuating system should have a very compact design and comprise fewer constituent components, is easier to produce and assemble, and comparatively inexpensive to manufacture compared to state-of-the-art actuating systems. Furthermore, it is an objective to provide a method of operating such a new actuating system.

This objective is solved by an actuating system for an actuatable door, said actuating system comprising the features of the invention as defined in the independent claims. Dependent claims define preferred embodiments.

More specifically an actuating system for an actuatable door comprises a rotatable drive shaft, a rotatable latch shaft, a latching device, and a locking device. The latching device comprises at least two latches that are non-rotatably mounted to the rotatable latch shaft and adapted for maintaining the actuatable door in a closed position when the at least two latches are in a latched position, a latch securing unit that is adapted for maintaining the at least two latches in the latched position when the latch securing unit is in a securing position, and at least two lock lever counterparts that are non-rotatably mounted to the rotatable latch shaft. The locking device comprises a lock lever that is non-rotatably mounted to the rotatable drive shaft and adapted for engaging with the at least two lock lever counterparts to prevent the latch securing unit from disengaging from the securing position thereby locking the at least two latches in the latched position when the lock lever is in a locked position.

The present technology includes a continuous latch shaft on which two latches are mounted. When the two latches are engaged in the respective fuselage side fittings, the actuatable door is restrained in the correct position relative to the fuselage side stops. When latched, the latch shaft is secured in position by its single operating mechanism, thereby satisfying the necessary latch securing means requirements of the airworthiness regulating authorities.

Once latched, the locking device may be engaged to prevent the latch shaft and the associated latches from unlatching. At the interface between the latching device and the locking device and on the side of the latch mechanism the latch securing unit provides two individual load paths to ensure that, in event of a failure in the latch mechanism, a sufficient number of latches will remain locked, thereby satisfying the single failure requirements defined by the airworthiness regulating authorities.

As one latch is sufficient to maintain the position of the actuatable door relative to the fuselage and each shaft is supported by three bush bearings, which ensure adequate functionality after shaft failure, the single failure criteria for the latching mechanism, as defined by the airworthiness regulating authorities, is fulfilled.

The present technology also ensures that, in the event of a disconnection of one of the two latches from its operating mechanism, net torques or forces will not tend to open the latches.

Furthermore, the latch securing unit and the locking device can be located at any position along the continuous latch shaft, thereby enabling a simplified sensing mechanism that allows to locate a corresponding door status indication panel in a region of the actuatable door that is clearly visible to the door operator.

The obvious benefits of the present technology include a reduction in reoccurring costs due to a reduced part count within the latching device, the locking device, and the door status indication mechanism. The cost of the initial design of the actuating system is reduced compared to state-of-the-art solutions thanks to a less complex design and fewer parts. The reduction in weight that results from the fewer parts should also not be underestimated.

Moreover, the simplified design reduces initial installation and maintenance efforts thanks to fewer adjustments. The risk of an incorrect installation of the actuatable door and/or any misadjustment is significantly reduced.

The reduction in the number of parts of the locking device also means that a reduction in the number of associated sensors and targets may be considered.

Furthermore, the reduction in required installation space in the most congested area of the door may allow for increased levels of thermal and acoustic insulation if desired.

According to one aspect, the lock lever and the at least two lock lever counterparts form at least two separate load paths when the lock lever is in the locked position.

If desired, the lock lever has a lock lever contact surface and the at least two lock lever counterparts have respective lock lever counterpart contact surfaces, whereby the lock lever contact surface engages with the respective lock lever counterpart contact surfaces of the at least two lock lever counterparts when the lock lever is in a locked position.

Illustratively, the rotatable drive shaft drives the rotatable latch shaft via the latch securing unit.

According to one aspect, the latch securing unit further comprises a linking element that couples the rotatable drive shaft with the rotatable latch shaft.

If desired, the linking element further may comprise a first bearing that rotatably couples the linking element with a rotatable drive shaft protrusion of the rotatable drive shaft, and a second bearing that rotatably couples the linking element with a rotatable latch shaft protrusion of the rotatable latch shaft.

Illustratively, a rotation of the rotatable drive shaft in latching direction causes, via the first bearing, a movement of the linking element in latching direction that causes, via the second bearing, a rotation of the rotatable latch shaft in latching direction.

If desired, the latching device may further comprise a stop bolt that stops the rotation of the rotatable latch shaft in latching direction when the at least two latches are in the latched position.

According to one aspect, the latching device further comprises an additional stop bolt that stops the rotation of the rotatable drive shaft when the latch securing unit is in the securing position.

Illustratively, the first bearing, the second bearing, the rotatable drive shaft, and the additional stop bolt of the latch securing unit form an overcenter clamp that is in an overcentered position in the securing position.

In the overcentered position, a rotation of the rotatable latch shaft against the latching direction may cause a further rotation of the rotatable drive shaft into the latching direction, thereby pushing the rotatable drive shaft protrusion against the additional stop bolt and maintaining the at least two latches in the latched position.

Illustratively, in the overcentered position, only a rotation of the rotatable drive shaft against the latching direction may cause the overcenter clamp to leave the overcentered position, thereby releasing the latch securing unit from the securing position.

According to one aspect, a further rotation of the rotatable drive shaft against the latching direction causes, via the latch securing unit a rotation of the rotatable latch shaft against the latching direction, thereby releasing the at least two latches from the latched position.

Moreover, a method of operating the actuating system described above includes the following operations: From an unlatched position, rotating the rotatable drive shaft in latching direction to cause, via the latch securing unit, a rotation of the rotatable latch shaft in latching direction that causes a movement of the at least two latches into the latched position; from the latched position, further rotating the rotatable drive shaft in latching direction to cause a movement of the latch securing unit into the securing position; and from the securing position, further rotating the rotatable drive shaft in locking direction to cause a movement of the lock lever into the locked position.

According to one aspect, the method may further include: from the locked position, rotating the rotatable drive shaft against the locking direction to cause a movement of the lock lever from the locked position, a movement of the latch securing unit from the securing position, and, via the latch securing unit, a rotation of the rotatable latch shaft against the latching direction that causes a movement of the at least two latches from the latched position.

Embodiments are outlined by way of example in the following description with reference to the attached drawings.

<FIG> shows an aircraft <NUM> with an aircraft airframe <NUM>, which is sometimes also referred to as fuselage <NUM>. Illustratively, the aircraft <NUM> comprises a passenger cabin 103a, a cargo deck 103b, and a flight deck or cockpit 103c. If desired, the aircraft <NUM> is accessible via a plurality of aircraft doors <NUM>, which exemplarily comprises several cabin access doors 104a, 104b, 104c, and 104d, as well as one or more cargo deck access doors 104e. By way of example, the passenger cabin 103a and the flight deck 103c are accessible via the cabin access doors 104a, 104b, 104c and 104d, and the cargo deck 103b is accessible via the one or more cargo deck access doors 104e.

The plurality of aircraft doors <NUM> may be adapted to close the aircraft airframe <NUM> in a fluid-tight manner. If desired, at least one of the plurality of aircraft doors <NUM> is a swiveling aircraft door. Illustratively, at least one of the plurality of aircraft doors <NUM> is an actuatable door.

If desired, aircraft <NUM> may include at least one actuatable door <NUM> as described below with reference to <FIG>. In other words, one or more of the plurality of aircraft doors <NUM> may be an actuatable door <NUM> as described below with reference to <FIG>.

Illustratively, the actuatable door may be movable between a closed position and an open position. In the closed position, the actuatable door may close an opening in the fuselage <NUM>, thereby preventing access from outside the aircraft <NUM>. In the open position, the actuatable door may provide access from outside the fuselage <NUM> to the aircraft passenger cabin 103a, the aircraft cargo deck 103b, and/or the aircraft flight deck 103c.

For the remainder of the description, the actuatable door is said to be in the closed position when the actuatable door completely closes the opening in the fuselage <NUM>. As an example, the actuatable door may at least airtightly close the opening in the fuselage <NUM> when the actuatable door completely closes the opening in the fuselage <NUM>. As another example, the actuatable door may prevent unauthorized access to the fuselage <NUM> when the actuatable door completely closes the opening in the fuselage <NUM>.

Furthermore, the actuatable door is said to be in a partially open position when the actuatable door partially closes the opening in the fuselage <NUM>, and the actuatable door is said to be in the fully open position when the opening in the fuselage <NUM> is free of the actuatable door. For example, no part of the opening in the fuselage <NUM> is covered by the actuatable door in the fully open position.

If desired, the actuatable door may include an actuating system such as actuating system <NUM> of <FIG> described below.

As shown in <FIG>, aircraft <NUM> is embodied by an airplane. However, the present embodiments are not limited to airplanes. Instead, any door that closes a boundary between two environments is likewise contemplated. By way of example, the present actuatable door may alternatively be applied to other aircrafts such as helicopters, drones, multicopters, etc., to other vehicles such as ships, spacecrafts, submarines, and so on.

Consequently, the present door is not limited to aircraft doors, but can likewise be applied to any arbitrary door that closes a boundary between two environments. However, for purposes of illustration, the present door is hereinafter described with respect to aircraft doors.

<FIG> shows an actuating system <NUM> for an actuatable door <NUM>. In other words, <FIG> shows an actuatable door <NUM> comprising actuating system <NUM>. The actuating system <NUM> is exemplarily adapted for reliably and securely latching and locking the actuatable door <NUM> in a closed position, such that the actuatable door <NUM> fulfils all relevant requirements defined by the competent authorities, such as e. in EASA CS <NUM>.

If desired, the actuatable door <NUM> may include an indication mechanism <NUM> that monitors the state of the actuating system <NUM>. For example, the indication mechanism <NUM> may detect whether the actuating system <NUM> is in an unlatched and unlocked, latched and unlocked, or latched and locked position.

As shown in <FIG>, the actuatable door <NUM> may include a door status indication panel <NUM>. The door status indication panel <NUM> may indicate the current status of the actuatable door <NUM> based on the information from the indication mechanism <NUM>. For example, the door status indication panel <NUM> may indicate whether the actuating system <NUM> is in an unlatched and unlocked, latched and unlocked, or latched and locked position.

Illustratively, the actuating system <NUM> includes a rotatable drive shaft <NUM> and a rotatable latch shaft <NUM>.

By way of example, actuating system <NUM> includes an actuating device. The actuating device may be adapted for actuating respectively rotating a rotatable actuating shaft. As an example, the actuating device may include an operating handle. If desired, the actuating device may include any device that is able to actuate respectively rotate the rotatable actuating shaft. For example, the actuating device may include a wheel, a knob, or a motor and any other device that is able to control the motor. If desired, the actuating device may be adapted for rotating the rotatable drive shaft <NUM> in operation.

Actuating system <NUM> may comprise a latching device <NUM> and a locking device <NUM>. The latching device <NUM> is described in more detail below with reference to <FIG>, and the locking device <NUM> is described in more detail below with reference to <FIG>.

Illustratively, the latching device <NUM> includes at least two lock lever counterparts <NUM>, <NUM>. The at least two lock lever counterparts <NUM>, <NUM> are non-rotatably mounted to the rotatable latch shaft <NUM>.

As shown in <FIG>, the locking device <NUM> includes a lock lever <NUM>. The lock lever <NUM> is non-rotatably mounted to the rotatable drive shaft <NUM>. Thus, rotation of the rotatable drive shaft <NUM> causes a rotation of the lock lever <NUM>.

If desired, the lock lever <NUM> may be non-rotatably mounted to the rotatable drive shaft <NUM> by means of at least one pin. In other words, the at least one pin may prevent a rotation of the lock lever <NUM> relative to the second rotatable drive shaft <NUM>.

The lock lever <NUM> may be adapted for engaging with the at least two lock lever counterparts <NUM>, <NUM> of the latching device <NUM>. The lock lever <NUM> engages with the at least two lock lever counterparts <NUM>, <NUM> to prevent the latch securing unit from disengaging from the securing position, thereby locking the at least two latches <NUM> in the latched position when the lock lever <NUM> is in a locked position.

As an example, a single lock lever <NUM> may engage with two separate lock lever counterparts <NUM>, <NUM> in the locked position. Thus, the lock lever <NUM> and the at least two lock lever counterparts <NUM>, <NUM> form at least two separate load paths.

The latching device <NUM> includes at least two latches <NUM>. As shown in <FIG>, the latching device <NUM> may include exactly two latches <NUM>. The at least two latches <NUM> are non-rotatably mounted to the rotatable latch shaft <NUM>. Thus, rotation of the rotatable latch shaft <NUM> causes a rotation of the at least two latches <NUM>.

If desired, a latch of the at least two latches <NUM> may be non-rotatably mounted to the rotatable latch shaft <NUM> by means of at least one pin. In other words, the at least one pin may prevent a rotation of the associated latch of the at least two latches <NUM> relative to the rotatable latch shaft <NUM>.

As shown in <FIG>, the two latches <NUM> are non-rotatably mounted to the ends of the rotatable latch shaft <NUM>, a first latch <NUM> at the forward end and a second latch <NUM> at the aft end of the rotatable latch shaft <NUM>. The at least two latches <NUM> are adapted for maintaining the actuatable door <NUM> in a closed position when the at least two latches <NUM> are in a latched position.

For example, a latch of the at least two latches <NUM> may be latchable at an associated counter peg provided at a door frame, non-represented for simplicity and clarity.

Illustratively, the at least two latches <NUM> may be implemented as hooks, as C-latches, as toggle latches, or as any other latches that may be latchable at associated devices (e.g., counter pegs, cylinders, or shafts) provided at a door frame. If desired, the at least two latches <NUM> may be implemented as cylinders or shafts and the associated devices provided at a door frame may be implemented as hooks or C-latches.

Illustratively, the latching device <NUM> includes a latch securing unit. The latch securing unit is adapted for maintaining the at least two latches <NUM> in the latched position when the latch securing unit is in a securing position.

By way of example, the rotatable drive shaft <NUM> drives the rotatable latch shaft <NUM> via the latch securing unit. As shown in <FIG>, the latch securing unit may include a linking element <NUM> that couples the rotatable drive shaft <NUM> with the rotatable latch shaft <NUM>. For example, the rotatable drive shaft <NUM> may have a rotatable drive shaft protrusion <NUM>, the rotatable latch shaft <NUM> may have a rotatable latch shaft protrusion <NUM>, and the linking element <NUM> may couple the rotatable drive shaft protrusion <NUM> with the rotatable latch shaft protrusion <NUM>.

<FIG> is a diagram of a sectional cut along the line B1-B3 through the illustrative actuating system <NUM> of <FIG> showing an illustrative latching device <NUM> with latch <NUM> and latch securing unit <NUM>. The latch <NUM> is shown in <FIG> in a latched position <NUM> in which the latch <NUM> engages with a counterpart in the door frame to maintain the actuatable door in a closed position, and the latch securing unit <NUM> is in a securing position <NUM>.

Illustratively, the latch securing unit <NUM> may include a linking element <NUM> that couples the rotatable drive shaft <NUM> with the rotatable latch shaft <NUM>. For example, the linking element <NUM> may have a first bearing <NUM> that rotatably couples the linking element <NUM> with a rotatable drive shaft protrusion <NUM> of the rotatable drive shaft <NUM>, and a second bearing <NUM> that rotatably couples the linking element <NUM> with a rotatable latch shaft protrusion <NUM> of the rotatable latch shaft <NUM>.

Consider the scenario in which the actuating system <NUM> is in an unlatched and unlocked position. In this scenario, the actuatable door may be moved in the door opening direction <NUM> to move the actuatable door from a closed to an open position. When the actuatable door is in the closed position, the actuating system <NUM> may be transitioned from an unlatched and unlocked position to a latched and unlocked position. Thereby, the rotatable drive shaft <NUM> may be rotated in latching direction <NUM>. For example, an actuating device (e.g., an electrical or mechanical connection from a door opening device) may rotate the rotatable drive shaft <NUM> in latching direction <NUM>.

The rotation of the rotatable drive shaft <NUM> in latching direction <NUM> may cause, via the first bearing <NUM>, a movement of the linking element <NUM> in latching direction <NUM>. The movement of the linking element <NUM> in latching direction <NUM> may cause, via the second bearing <NUM>, a rotation of the rotatable latch shaft <NUM> in latching direction <NUM>. Thus, the rotatable drive shaft <NUM> drives the rotatable latch shaft <NUM>, and a rotation of the rotatable drive shaft <NUM> in latching direction <NUM> results in a rotation of the rotatable latch shaft <NUM> in latching direction <NUM>.

If desired, the latching device <NUM> may include a stop bolt <NUM>. The stop bolt <NUM> may stop the rotation of the rotatable latch shaft <NUM> in latching direction <NUM> when the at least two latches <NUM> have reached the latched position <NUM>. Now, the actuating system <NUM> is in the latched and unlocked position, and the corresponding actuatable door is in the closed position and prevented from moving to an open position.

The rotatable drive shaft <NUM> may further rotate in latching direction <NUM> until an additional stop bolt <NUM> stops the rotation of the rotatable drive shaft <NUM>. When the additional stop bolt <NUM> stops the rotation of the rotatable drive shaft <NUM>, the latch securing unit <NUM> is in the securing position <NUM>.

For example, bearings <NUM>, <NUM>, the rotatable drive shaft <NUM>, and the additional stop bolt <NUM> of the latch securing unit <NUM> may form an overcenter clamp <NUM>. The overcenter clamp <NUM> may reach a centered position when the stop bolt <NUM> stops the rotation of the rotatable latch shaft <NUM> in latching direction <NUM>. In the centered position, the rotation axes of the bearings <NUM>, <NUM> and of the rotatable drive shaft <NUM> are aligned.

Upon a further rotation of the rotatable drive shaft <NUM> in latching direction <NUM> from the centered position, the axes of bearing <NUM> and rotatable drive shaft <NUM> remain at the same location as in the centered position, while the axis of bearing <NUM> moves in latching direction <NUM> until the drive shaft protrusion <NUM> interacts with the stop bolt <NUM>. At this point, the overcenter clamp <NUM> has reached an overcentered position <NUM> and the latch securing unit <NUM> is in the securing position <NUM>.

In the overcentered position <NUM>, a rotation of the rotatable latch shaft <NUM> against the latching direction <NUM> causes a further rotation of the rotatable drive shaft <NUM> into the latching direction <NUM>, thereby pushing the rotatable drive shaft protrusion <NUM> against the stop bolt <NUM> and maintaining the at least two latches <NUM> in the latched position <NUM>. Thereby, the at least two latches <NUM> are secured in the latched position by their own latch securing unit <NUM>, which fulfils the requirements of the airworthiness regulating authorities.

Thus, in the overcentered position <NUM>, only a rotation of the rotatable drive shaft <NUM> against the latching direction <NUM> causes the overcenter clamp <NUM> to leave the overcentered position <NUM>, thereby releasing the latch securing unit <NUM> from the securing position <NUM>.

A further rotation of the rotatable drive shaft <NUM> against the latching direction <NUM> causes, via the latch securing unit <NUM> a rotation of the rotatable latch shaft <NUM> against the latching direction <NUM>, thereby releasing the at least two latches <NUM> from the latched position <NUM>. Now, the actuating system <NUM> has returned to the unlatched and unlocked position.

<FIG> is a diagram of a sectional cut along view A1-<NUM> through the illustrative actuating system <NUM> of <FIG> showing an illustrative locking device <NUM>. The locking device <NUM> includes a lock lever <NUM> that is non-rotatably mounted to the rotatable drive shaft <NUM>.

The lock lever <NUM> may be adapted for engaging with the at least two lock lever counterparts <NUM>, <NUM> of the latching device <NUM> to prevent the latch securing unit (e.g., latch securing unit <NUM> of <FIG>) from disengaging from the securing position. Thus, the lock lever <NUM> of locking device <NUM> may lock the at least two latches <NUM> in the latched position <NUM> when the lock lever <NUM> is in a locked position <NUM>. When the lock lever <NUM> is in the locked position <NUM>, the actuating system <NUM> is in a latched and locked position.

Illustratively, lock lever <NUM> has a lock lever contact surface <NUM> and the at least two lock lever counterparts <NUM>, <NUM> have respective lock lever counterpart contact surfaces <NUM>. When the lock lever <NUM> is in the locked position <NUM>, the lock lever contact surface <NUM> engages with the respective lock lever counterpart contact surfaces <NUM> of the at least two lock lever counterparts <NUM>, <NUM>. Thus, the lock lever <NUM> and the at least two lock lever counterparts <NUM>, <NUM> form at least two separate load paths.

Consider the scenario in which the actuating system <NUM> is in a latched and unlocked position in which the stop bolt <NUM> has stopped the rotation of the rotatable latch shaft <NUM> in latching direction <NUM> and the at least two latches <NUM> have reached the latched position <NUM>.

In this scenario, a further rotation of the rotatable drive shaft <NUM> in latching direction <NUM> may cause the latch securing unit into the securing position and a rotation of the lock lever <NUM> into the locked position <NUM>.

Starting from the locked position <NUM>, a rotation of the rotatable drive shaft <NUM> against the locking direction <NUM> may cause the lock lever <NUM> to disengage from the at least two lock lever counterparts <NUM>, <NUM>, thereby moving the actuatable system <NUM> from a latched and locked position to a latched and unlocked position.

The at least two lock lever counterparts <NUM>, <NUM> provide at least two separate load paths. Each load path is capable of reacting to any load that is generated by the latching device <NUM> on the locking device <NUM>. Each shaft, rotatable latch shaft <NUM> and rotatable drive shaft <NUM> may be supported by three bush/bearing positions, and each one of the at least two latches <NUM> is capable alone to keep the actuatable door in position relative to the door frame counterparts. Thereby, the requirement of the airworthiness regulating authorities, that after a failure of any individual component within the latching device <NUM>, a sufficient number of latches <NUM> shall remain engaged is fulfilled.

<FIG> is a flowchart of a method <NUM> showing illustrative operations of operating the illustrative actuating system <NUM> of <FIG>.

Consider the scenario in which the actuating system is in an unlatched position and the corresponding actuatable door in a closed position. In this scenario, from the unlatched position, an actuating device may, during operation <NUM>, rotate the rotatable drive shaft in latching direction to cause, via the latch securing unit, a rotation of the rotatable latch shaft in latching direction that causes a movement of the at least two latches into the latched position. For example, from the unlatched position, an electrical or manual actuating device may rotate the rotatable drive shaft <NUM> of <FIG> in latching direction <NUM> to cause, via the latch securing unit <NUM>, a rotation of the rotatable latch shaft <NUM> in latching direction <NUM> that causes a movement of the at least two latches <NUM> into the latched position <NUM>.

From the latched position, the actuating device may, during operation <NUM>, rotate the rotatable drive shaft in latching direction to cause a movement of the latch securing unit into the securing position. For example, from the latched position <NUM> of <FIG>, the actuating device may further rotate the rotatable drive shaft <NUM> in latching direction <NUM> to cause a movement of the latch securing unit <NUM> into the securing position <NUM>.

From the securing position, the actuating device may, during operation <NUM>, further rotate the rotatable drive shaft in locking direction to cause a movement of the lock lever into the locked position. For example, from the securing position, the actuating device may further rotate the rotatable drive shaft <NUM> of <FIG> in locking direction <NUM> to cause a movement of the lock lever <NUM> into the locked position <NUM>.

If desired, from the locked position, the actuating device may rotate the rotatable drive shaft against the locking direction to cause a movement of the lock lever from the locked position, a movement of the latch securing unit from the securing position, and, via the latch securing unit, a rotation of the rotatable latch shaft against the latching direction that causes a movement of the at least two latches from the latched position. For example, from the locked position <NUM> of <FIG>, the actuating device may rotate the rotatable drive shaft <NUM> against the locking direction <NUM> to cause a movement of the lock lever <NUM> from the locked position <NUM>, a movement of the latch securing unit <NUM> of <FIG> from the securing position <NUM>, and, via the latch securing unit <NUM>, a rotation of the rotatable latch shaft <NUM> against the latching direction <NUM> that causes a movement of the at least two latches <NUM> from the latched position <NUM>.

It should be noted that modifications to the above described embodiments are within the common knowledge of the person skilled in the art and, thus, also considered as being part of the present invention.

For instance, stop bolt <NUM> of latching device <NUM> of <FIG> may be omitted when the at least two latches have an implicit stop such as if the latches are in form of a peg that reaches the end of a slot when the actuating system is in the latched position <NUM>. Alternatively, stop bolt <NUM> may be placed such that it interacts with at least one of the at least two lock lever counterparts <NUM>, <NUM> of <FIG>.

Claim 1:
An actuating system (<NUM>) for an actuatable door (<NUM>), comprising:
a rotatable drive shaft (<NUM>);
a rotatable latch shaft (<NUM>);
a latching device (<NUM>) comprising:
at least two latches (<NUM>) that are non-rotatably mounted to the rotatable latch shaft (<NUM>) and adapted for maintaining the actuatable door (<NUM>) in a closed position when the at least two latches (<NUM>) are in a latched position (<NUM>),
a latch securing unit (<NUM>) that is adapted for maintaining the at least two latches (<NUM>) in the latched position (<NUM>) when the latch securing unit (<NUM>) is in a securing position (<NUM>), and
at least two lock lever counterparts (<NUM>, <NUM>) that are non-rotatably mounted to the rotatable latch shaft (<NUM>); and
a locking device (<NUM>) comprising:
a lock lever (<NUM>) that is non-rotatably mounted to the rotatable drive shaft (<NUM>) and adapted for engaging with the at least two lock lever counterparts (<NUM>, <NUM>) to prevent the latch securing unit (<NUM>) from disengaging from the securing position (<NUM>) thereby locking the at least two latches (<NUM>) in the latched position (<NUM>) when the lock lever (<NUM>) is in a locked position (<NUM>).