DESCRIPTION The Related Art

The invention relates to mechanisms in vehicle seats that connect the backrest part to the main frame. The invention particularly relates to backrest mechanisms that absorb some portion of the impact energy on vehicle seats by means of pieces that are torn when the backrest makes a rotation in forward direction with a certain amount of force, and reduce the risk of injury by allowing the forward tilting movement of the backrest. The Prior Art

High forces (16G forward) are formed as a results of situations such as vehicle accidents or emergency landing of planes, which causes passengers to hit their heads to the front seat. In such cases, the seats are expected to absorb these impacts and minimize the harm on the passengers, and especially avoid dangerous situations while the passengers escape to emergency exits on planes. Sharp edges and pieces that break away and may cause slipping are unwanted situations.

In the prior art systems, embodiments made of special plastic materials formed at the rear part of the backrest are used as shock absorbing components in such cases of accidents. In some applications, extra components such as pads, foams etc. are used to provide springiness. In the US patent No. US 6142563, entitled "Vehicle seat with energy absorbing deformable structural material", an invention that would pose an example for such an embodiment is provided. In said invention, a cellular structure material having elastic deformable characteristic is used in at least one of the seat, backrest, or armrest that form the vehicle seat.

In said embodiments, the shock absorbing material loses its function in time and become brittle due to environment conditions. Moreover, the broken pieces during an accident may cause shrapnel effect and give harm to the passengers. Besides, they may also prevent the passengers from reaching emergency exits. One of the most significant drawbacks of using additional components is the increase in weight. Increase in weight means very high fuel costs especially in aviation. As a result, the need for backrest mechanisms which absorb some portion of the impact energy on vehicle seats by means of pieces that are torn when the backrest makes a rotation in forward direction with a certain amount of force, and reduces the risk of injury by allowing the forward tilting movement of the backrest, and the inadequacy of the prior art solutions about the subject have necessitated an improvement in the related technical field.

Purpose of the Invention

The invention relates to a backrest mechanism, which meets the above said requirements, eliminates all of the drawbacks, and brings some additional advantages.

The main purpose of the backrest mechanism according to the invention is to ensure absorption/damping of a portion of the mechanical energy formed during impact and accident situations by means of pieces that prevent the backrest from moving forward by rotating around the bushing connection and that are torn instead of being ruptured/broken, only when certain amount of force is applied. Specially designed shear plates are resistant against low forces such as forces frequently applied by passengers for leaning, support etc. purposes during service, but they are torn above a limit force, such as high forces that occur due to the head impact of passengers in cases like emergency landings, and thus allow the seat to tilt forward. In this way, the potential harm on the passenger due to the impact on the seat backrest is minimized. Since the shear plates come apart and get separated during the accident, the mechanism is not damaged at all and following the accident, the seat backrest that is tilted forward can be brought back to its previous position with a small amount of force that would not cause trouble for the passenger. In this way, the backrest would not pose an obstacle while the passengers escape to emergency exits. By means of a material deformation that occurs in an area that is not in direct contact with the passenger, the possible harm on the passenger is also reduced. Additionally, if there is not big damage on the seat following the accident, the mechanism can be used again only by renewing the shear plates. As in the prior art systems, energy damping at the region where the passenger hits his/her head poses a risk. In the invention, the function of mechanical energy damping directly at the backrest mechanism increases safety.

In order to achieve the above said purposes in the most general sense, a backrest mechanism is developed which absorbs some portion of the impact energy on vehicle seats by means of pieces that are torn when the backrest makes a rotation in forward direction with a certain amount of force, and reduces the risk of injury by allowing the forward tilting movement of the backrest. The developed backrest mechanism comprises: at least one bushing that passes through the backrest hinge formed on the backrest and the bush bearing formed on the seat base frame, and enabling the backrest to make rotational motion,

at least one connecting piece formed on at least one shear plate, which is positioned between the seat base frame and the backrest, and when a force is applied on the seat, which is torn in order to absorb the impact and allows the backrest to tilt forward, and ensuring connection of the shear plate with the backrest and preventing the passenger from being harmed during the impact,

at least one piston connected to the seat base frame and allowing the backrest to tilt backward with a certain amount of backward tilting motion,

at least one lever that transfers motion between the piston and the backrest,

at least one leaning surface formed on said backrest and connected to the seat base frame so as to restrict the backward tilting movement of the backrest,

at least one pin that is connected to the lever so as to ensure its connection with the leaning surface and/or ensure connection of the shear plate,

at least one pin housing formed on the shear plate and bearing the pin,

at least one spring clamp connected to said backrest and thus connected to the pin, and used for fixing thereof.

The structural and characteristic features of the invention and all of its advantages shall be understood better with the figures and the detailed description given below in reference to the figures, and therefore, the assessment should be made by taking into account the said figures and detailed explanations.

Figures for Better Understanding of the Invention

For better understanding of the embodiment of the present invention and its advantages with its additional components, it should be evaluated together with below described figures. Figure - 1 : is the demounted view of the backrest mechanism according to the invention while it is on the seat.

Figure - 2: is a close-up view of the shear plates found at the backrest mechanism according to the invention, during mounting.

Figure - 3: is a demounted close-up view of the backrest mechanism according to the invention while it is on the seat.

Figure - 4: is a mounted close-up view of the backrest mechanism according to the invention while it is on the seat. Figure - 5: is a perspective view of the shear plates found at the backrest mechanism according to the invention, during mounting.

Drawings do not have to be scaled and details not necessary for understanding the present invention may be neglected. Moreover, components which are at least widely equal or which have at least widely equal functions are shown with the same number.

Parts References

10 Seat base frame 34 Connecting piece

1 1 Bush bearing 35 Pin

20 Backrest 36 Connector

21 Backrest hinge 37 Spring clamp

22 Leaning surface 40 Lever

23 Lever fork 41 Lever hinge

24 Connection housing 42 Pin reference

30 Backrest mechanism 43 Piston connecting piece

31 Bushing 50 Piston

32 Shear plate 60 Seat

33 Pin housing Detailed Description of the Invention

In this detailed description, the preferred embodiments of the invention are only disclosed for better understanding of the subject without forming any limiting effect. In the vehicle seats (60), an example of which is given in Figure 1 , the connection of the backrest (20) with the seat base frame (10) is made by means of backrest mechanisms (30). In some backrest mechanisms (30), just like in the invention, the backrest (20) is allowed to make a rotational motion by means of a backrest hinge (21 ) formed on the backrest (20) and a bushing (31 ) that passes through a bush bearing (1 1 ) formed on the seat base frame (10). In the developed backrest mechanism (30), different from the prior art applications; at least one shear plate (32) is found, which is positioned between the seat base frame (10) and the backrest (20), and which is torn when pulled with a certain amount of force and/or when the limit force (the force formed by the impact of the passenger's head) is exceeded, and thus allows backrest (20) to rotate in forward direction as the pin (35) becomes free. Figure 2 shows a close-up view of the shear plates (32) found at the backrest mechanism (30) according to the invention, during mounting. In a preferred embodiment of the invention, the bushing (31 ) is found on the backrest hinge (21 ) formed on the lever fork (23) piece connected to the backrest (20). The leaning surface (22), which is connected to the seat base frame (10) and thus restricts the backward tilting movement of the backrest (20), is also formed on the lever fork (23) in the preferred embodiment. Similarly, the connection housing (24) formed on the lever fork (23) ensures connection of the shear plate (32).

Figure 3 shows a close-up view of the backrest mechanism (30) in demounted state on the seat (60). The piston (50) that is connected to the seat base frame (10) enables the backrest (20) to come backwards with a certain amount of backward tilting motion. For this purpose, the motion transfer between the piston (50) and the backrest (20) occurs by means of a lever (40). The pin (35) shown in Figures 2 and 3 is connected to the lever (40) in the preferred embodiment, and thus enables its connection with the leaning surface (22) and connection of the shear plate (32). The pin reference (42) formed at the middle part of the lever (40) is the space through which the pin (35) passes so as to make free rotational motion. Also, the lever hinge (41 ) formed at the tip of the lever (40) enables its connection to the bushing (31 ) such that it would make free rotational motion. The piston connecting piece (43) formed at the other end of the lever (40) is the component where the piston (50) is connected.

A connecting piece (34) ensuring connection of the shear plate (34) with the backrest (20), or in other words, with the lever fork (23) and a pin housing (33) bearing the pin (35) are formed on the shear plate (32) as can be seen in Figure 2. The shear plate (32) is made of metal sheet in a preferred embodiment and the amount of force and impact it would resist can be adjusted by changing its design. A spring clamp (37) connected to the backrest (20) through the lever fork (23) allows its fixing via connection with the pin (35).

The backrest mechanism (30) is seen in Figure 4 after mounting and holds the seat (60) in normal position as shown in Figure 5. The backrest (20) is connected to the seat base frame (10) through the lever fork (23). For this purpose, the bushing (31 ) passes through the backrest hinge (21 ) and the lever hinge (41 ), and it is placed at the bush bearing (1 1 ). The pin (35) supported at the pin reference (42) contacts the leaning surface (22) in normal position, and engages with the spring clamp (37) that is connected to the lever fork (23). The shear plates (32) also engage with the pin (35) and connect to the lever fork (23) by means of connection components (36). The piston (50) is positioned between the seat base frame (10) and the piston connecting piece (43). When leaned on the backrest (20) that is found in upright state in normal position, the leaning surface (22) pushes the lever (40) forward by means of the pin (35) and thus compresses the piston (50). When the user stands up, the piston (50) releases the accumulated potential energy to push the lever (40) back and brings the backrest (20) back to its normal position. The backrest (20) does not tilt forward against normal forces, since it is connected to the pin (35) and from there to the lever (40) by means of the shear plates (32). In the invention, a seat (60) used in aircrafts is given as an example. According to aviation rules, the backrest (20) always needs to be in upright position during emergency landing situations. The backrest mechanism (30) is designed according to emergency landing position, and during emergency landing, with a certain level of force that is formed due to the own moment of the backrest (20) and/or the impact of the passenger's head, the shear plates (32) are torn and separates the pin (35) and therefore the lever (40) piston (50) system from the backrest (20). In this case, the backrest (20) can be tilted forward. In this way, while the impact energy is absorbed by shear plates (32), the backrest (20) tilts forward so as to minimize the amount of damage on the passenger due to impact. The amount of force and impact the shear plates (32) would resist can be adjusted by changing their design and numbers.

The forward tilted state of the backrest (20) is not sufficient alone in aviation for absorbing impact. Since the backrest (20) that tilts forward towards the passenger sitting in the front, it creates a domino effect and poses the risk of obstructing the exit of passengers. In addition to minimizing the possible harm on the passengers, the backrest mechanism (30) should also not obstruct the exit of the passengers. Therefore, the passenger needs to bring the backrest (20) back to upright position and exit to the corridor. In the developed backrest mechanism (30), the passenger can easily lift and reposition the 2-3 kg weight backrests (20) with low forces around 150 N. According to aviation standards, the seat (60) cannot get a certificate if this force is exceeded. When the backrest (20) is lifted, the pin (35) engages with the spring clamp (37) that is connected to the lever fork (23) and stays there, and preferably does not fall down forward as long as the force applied does not exceed 45 N that is stated in the regulations. Since the shear plates (32) are torn with the impact, they do not form an obstacle during this movement.