A DOOR LATCH MECHANISM

Technical Field

This invention relates to a latch mechanism that allows for safe opening and closing of doors in aircraft during flight or at parking position. Former Techniques

In today's aircrafts in use, problems arise with doors like icing or clutching, due to low temperatures. Since aircraft doors have quite complicated systems, they usually incorporate multiple mechanisms and parts. These complicated mechanisms render it hard if not impossible to manipulate the door in the event of a malfunction, resulting in prolonged repair and maintenance times. Furthermore, there have been accidents reported in the past, due to pressurizing of the aircraft doors. The problems were mainly caused by differential pressure, which, in fact, pose severe troubles for the door operator in addition to endangering operation are no longer an issue, thanks to the solution provided by the latching system and inwardly opening cabin door mechanisms, which form the subject of the present invention.

In the technique, there is a variety of latching mechanisms for doors opening inwards of an aircraft. In many aircraft designs, doors open outwards of the aircraft. In many aircraft examples, door handles are located in such a way to facilitate inwards of the aircraft's interior and cargo area, in the aircraft's section.

Examples of practical implementations in the technique that are similar in nature to the present invention include the International patent document WO2009051875, wherein notion is made of an external door used to gain access to the cargo area in an aircraft fuselage. The door includes a latching system, a lock monitoring system, an up-lock used to secure the door in an open position, and an actuating system that assists in at least either of opening or closing the door. The latching system works with the movement of the latching system components. The latching system includes a monitoring device that prevents the aircraft from being pressurized in case of a malfunction in the latching system. The latching system includes a lock system that prevents operation of the latch handle accidentally or by ground loading or flight forces. The systems of the door are preferably manually operated, and utilize rigid elements. The purpose of this invention has been to access the cargo area of the aircraft, externally. The system is complicated and the gears have been utilized to transmit the motion of the mechanism.

Another practical implementation known to exist in the current state of the art is that depicted in US patent publication with publication no. US2011248514, which mentions of a door mechanism for the aircraft door. The door includes a multitude of interconnecting components both at fuselage and door sides. Each fuselage interconnecting component incorporates a pin and an eccentric rotary cylinder which can be attached to this pin. Each door connection part includes an eccentric rotary handle, designed to wrap around at least one section of the rotary cylinder. This document describes a lock mechanism that is used to open the aircraft door outwardly. The latching system is employed at one side of the door and direct manual operation or electric motor can be used as moving mechanism. The cylinders of the doors are needed to be pushed side wards, to allow complete latching.

Another practical implementation known to exist in the current state of the art is that depicted in US patent publication with publication no. US5305969, which mentions of a latching and latching mechanism designed for cargo hatch doors in an aircraft. As part of this invention, contents of a latch mechanism are described, which is used to open and close aircraft doors and powered by a translational motion. When the handle is rotated, door moves upward and at that position door passes door stops and can be opened. During flight, when the door is forced to be opened, the pressurized door opening mechanism disables itself, to prevent movement of the handle. In this invention, the door moves upward, in order to release the door from its door stops. In addition, the security system used locks the mechanism with the help of the pressurized vent cover. However, this invention would drive inefficient in the event of any malfunction taking place in the vent cover. The present invention provides latching with a much simpler mechanism, thanks to its design which is superior in many aspects than the above mentioned patent documents. As it is designed for use under literally any condition, it doesn't need any particular auxiliary mechanism. It is able to better respond to the door operator's needs, compared to those systems forming subject of the above mentioned inventions, in respect of latching safety. It does not pose any danger and risks to the user in respect of operation.

Brief Description of the Invention The preamble with this invention is to realize a door latch system that fully operates by mechanical means and yet facilitates operation under any circumstances, including but not limited to cases of emergency.

Another purpose intended with this invention is to realize a door latch system that can easily be manipulated in case of a malfunction, due to the simple system and parts design.

A further purpose of this invention is to realize a door latch system which eliminates all safety problems associated with pressurized doors. A further purpose of this invention is to realize a door latch system that creates no risks for the door operator.

A further purpose of this invention is to realize a door latch system, wherein the door handle equipped uses the door surface instead of the cargo area.

Another purpose of this invention is to realize a door latch system that facilitates for detachment in order to enable coping up with the problem of icing on doors. Another purpose of this invention is to realize a door latch system that enables the opening of the door getting stuck in position due to harsh ambient conditions, from its external surface by the use of manually applied force.

Detailed Description of the Invention

A door latch system realized to reach at the core purpose of this invention is shown in the attached figures, which include:

Figure 1- The perspective view of the door latch system.

Figure 2- The exploded view of the latching mechanism.

Figure 3- The front view of the latching mechanism on the door.

Figure 4- Perspective view of the latch and the latch guide.

Figure 5- Perspective view of the latch mechanism inside the aircraft.

Figure 6- Front view of the outer handle from outside of the aircraft.

Figure 7- Side view of the latch mechanism in both latched and unlatched position.

Figure 8- Front view of the inner handle in unlatched inside the aircraft.

Figure 9- Front view of the inner handle in latched position inside the aircraft. Figure 10- Front and side views of the door with latch mechanism inside the aircraft. The components in the figures are individually enumerated, and the defined below on respective number basis.

I- Latch mechanism

2- Inner handle

3- Quick Release pin

4- Outer handle

5- Inner handle assembly

6- Sensor rod

7- Target lever

8- Handle overcentering spring

9- Latch system

10- Mechanism rod

I I- Latch shaft

12- Latch shaft bearing

13 - Latch shaft bearing fitting

14- Shaft lever

15- Latch shaft overcentering spring

16- Teflon protection

17- Side fitting

18- Centering ring

19- Latch

20- Lock warning piece

21- Lock warning window

22- Latch guide

The door latch mechanism (1) enabling safe opening and closing of doors in aircraft, which forms the subject of the present invention, includes:

- at least one inner handle (2) enabling the opening of door with application of force from inside the aircraft, at least one Quick Release Pin (3) that prevents the door from being opened externally,

at least one outer handle (4) enabling the opening of door with application of force from outside the aircraft,

at least one inner handle assembly (5), to which the inner handle (2) and outer handle (4) are attached reciprocally,

At least one sensor rod (6) that provides door open or closed warning signals and is attached to the inner handle assembly (5),

at least one inner handle assembly (7) which transmits the movements of the inner handle (2) and outer handle (4) to the sensor mechanism and is attached to the sensor rod (6),

at least one handle overcentering spring (8) attached to the Inner handle assembly (5), to force the inner handle (2) towards closing position first and opening position next, when the door is opening, and, towards opening position first and closing position next, when it is closing,

the latching system (9) that ensures the door's remaining sealed without getting affected by any mechanical failures and malfunctions as may occur during flight and is attached to the inner handle assembly (5) by mechanism rod,

at least one mechanism rod (10) that transmits the rotary motion generated by the inner handle assembly (5) to the latch assembly (9) through the inner (2) and outer handles (3) and interconnects the inner handle assembly (5) and the latch assembly (9),

at least one latch shaft (11) which is connected to the inner handle assembly (5) by shaft lever (14) and mechanism rod(10 at least one latch shaft bearing (12) that pulls all the stresses created during installation of the latch shaft (1 1) on the door frame and the use of it after that, at least one latch shaft bearing fitting (13) which attaches the latch shaft bearing (12) on to the door frame, - at least one shaft lever (14) that transmits the motion of inner handle (2) or outer handle (4) it receives through the mechanism rod (10) onto the latch shaft (1 1),

- at least one latch shaft overcentering spring (15) fitted to shaft lever (14) of the latch shaft (14) that fixes the latch shaft (1 1) in locked position when the connection of the inner handle (2) or outer handle (4) is broken,

- at least one Teflon protection (16), which ensures that deflection of the latch shaft (11) remain in the safe range, when overload is applied from the inner handle (2) or outer handle (4) and is applied all around the latch shaft (1 1),

- a side fitting (17) that ensures successful housing of the latch shaft (1 1) on the door frame and is fitted at both ends of the latch shaft (11),

- a centering ring (18) that ensures successful housing of the latch shaft (1 1) on the door frame and is fitted at both ends of the latch shaft (1 1),

- the latch (19), which functions as a lock in between the door and its frame through the latch shaft (1 1) and is fitted at both ends of the latch shaft (11), a lock warning piece (20) fitted at both ends of the latch shaft (11) which shows motion of inner handle (2) or outer handle (4) motions in open or closed status on the latch (19), and

- the lock warning window (21) attached on the door frame showing open or close signs above the lock warning piece (20),

- the latch guide (22) fitted at both ends of the latch shaft (11) to guide and align movements of the latch assembly (9) and latch (19). The aircraft door latch mechanism (1) is found on the rear fuselage of the aircraft, so as to meet all kinds of ergonomic needs preplanned in its structure. Most aircraft employ doors opening outwards unlike the present invention, which open sliding inwards and then upwards. The door latch mechanism (1) attaches the door frame to the aircraft fuselage at both sides of the door with a pair of latching assemblies (9). The latching process takes place in time of mechanical movement of the door. As the door latch mechanism (1) is automatically blocked under pressure, it eliminates all security concerns. Capable of being used under any circumstances including but not limited to emergencies, by operation based totally on mechanical motions, the door latch mechanism (1) facilitates for easy access and manipulation in case of a malfunction as well, due to its simple system and parts design. This mechanism (1) enables opening of the door from its external surface when outer handle (4) is jammed/covered by ice due to harsh environmental conditions, by application of hand force. The door latch mechanism (1), in its most generic embodiment, consists of two door handles one located internally and the other externally (2, 4), a latch shaft (1 1), two latch shaft bearings (12) and two latch guide (22) aligned opposite to each other. Whenever an attempt is made for opening the door from inside, the inner handle (2) rotates 90° clockwise. When the door is moved from inside, the outer handle (4) does not rotate. Whenever an attempt is made for opening the door from outside, both the inner and outer handles (2, 4) move together.

The quick Release pin (3) is used to lock the mechanism (1) and prevent its future inadvertent operation, when the aircraft is at parking position. Before a flight, the quick release pin (3) should be removed from its place. When the door latch mechanism (1) is actuated by the inner handle (2), the latch (12) moves and takes latched position accordingly inside the latch guide (22).

The Inner handle assembly (5) transfers the rotational motion of the inner handle (2) or outer handle (4) to the latch assembly (9).

The sensor rod (6) is the component which triggers the motion of the sensor mechanism that provides the "door open" or "door closed" signals. The target lever (7) is the component, which enables transfer of the movements of inner and outer handles (2, 4) to the sensor mechanism. The handle overcentering spring (8) guarantees the door to be in position at either open or closed status. This handle overcentering spring (8) is always loaded with compression load. The inner or outer handle (2, 4) shows the tendency of keeping the door in closed position if it's angle in the direction of opening the door is at or below 45° or, in open position if it's angle in the same direction is between 45° and 90°. The handle overcentering spring (8) is the safety component that prevents the door from opening inadvertently, due to vibrations.

The mechanism rod (10) is a device that transmits the rotational motion produced by the motion of the inner handle assembly (5) from inner (2) or outer handle (4) to the latch shaft (11). The latch shaft (1 1) ensures that movements of the latch assembly (1) are transferred to the latch (19).

The latch shaft bearing (12) carry the stresses as may occur both during the installation of the latch shaft (11) in its place on the door frame and during its use thereafter. The latch shaft bearing fitting (13) is a U shaped member that wraps around the latch shaft bearing (12) and ensures that the bearing (12) fits firmly on the door frame. The shaft lever (14) ensures that the door remains closed during a flight without being affected by mechanical failures, together with the centering spring (8).

The shaft lever (14) transmits the motion from the inner and outer handles (2, 4) that it receives from the mechanism rod (10) to the latch shaft (1 1). The latch shaft overcentering spring (15) of the latch shaft is a safety component that prevents unintended opening of the door in time of flight, by ensuring the latch shaft (1 1) remain in locked position, in case the latch shaft (1 1) loses its connection with the inner or outer handles (2, 4). The Teflon protection (16) is a system component that ensures that deflection of the latch shaft (1 1) to remain in a safe range, when jamming load is applied from the inner handle (2) or outer handle (4) and is transmitted through the latch shaft (1 1). The side fitting (17) gets the stresses that the latch shaft (1 1) may form on the door frame and ensures successful housing of the latch shaft (1 1) on the door frame. Located in between the side fitting (17) and latch (19) as inserted onto the latch shaft (11), the centering ring (18) ensures axial centering of the latch shaft (11) on the door frame. The bearing (12) inserted onto the latch shaft (1 1) is a component that transmits the motion inside the latch shaft bearing fitting (13). The member which displays the open or closed position of the inner handle (2) and outer handle (4) over the latch (19) is a lock warning piece (20). The lock warning window (21) attached on the door frame, shows open or closed status of the door latch mechanism (1) above the lock warning piece (20). The latch guide (22) guides and aligns movements of the latch (19).

Since the door is of a non-hazardous type, door poses no risk to the door operator by its structural design; the latch mechanism (1) is the only need for latching the door. When the door is in latched position, the inner handle (2) stays in horizontal position and when the door is in unlatched position, the inner handle (2) stays in vertical position.

The door latch mechanism (1) is designed so as not to allow water ingress and/or icing to take place inside the aircraft, howsoever. The outer handle (4) is a critical part in respect of providing a sound level of proofing and insulation.

In view of these basic concepts enumerated above until this point, the "Door Latch Mechanism (1)" has a wide area of potential application and diverse potential uses, with or without further improvement, wherefore, the invention tried to be described herein may hot be limited to the examples divulged herein, but the embodiment should be construed as indicated in the claims that follow, in its basic form.