PATENTSCOPE will be unavailable a few hours for maintenance reason on Tuesday 19.11.2019 at 4:00 PM CET
Search International and National Patent Collections
Some content of this application is unavailable at the moment.
If this situation persists, please contact us atFeedback&Contact
1. (WO2010075900) ARTICULATING DEVICE FOR VEHICLE SEAT
Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

ARTICULATING DEVICE FOR VEHICLE SEAT

Field of the Invention

This invention relates to the field of devices for moving a seat of a vehicle. More particularly, this invention relates to an articulating device for facilitating a person to get in/out of a vehicle by adjusting the position of the seat.

Background of the Invention As is well known to those skilled in the art of designing seating devices for vehicles, people may experience considerable difficulty when getting in/out of a vehicle. Two movements need to be performed in order to get in/out of a vehicle: a raising/lowering movement and a rotational movement. These movements may be difficult, for example, when the seat of the vehicle is in a low position (as is the case in sports cars) or for elderly people, people suffering obesity or with some physical handicap. This problem is further exacerbated when the seat is placed in a relatively small place and when the steering wheel of the vehicle can be in the person's way.

Furthermore, numerous studies have shown that the repetition of these movements can lead to a loss of normal spinal motion pattern, which causes pain and/or neurologic dysfunction. Low back pain (LBP) is a common medical problem. There is a 50-70% chance of a person having LBP during his or her lifetime, with a prevalence of about 18%. In industrialized societies, LBP is expensive, costing an estimated $15 to $50 billion per year in the USA alone. A further more severe problem associated with the loss of normal spinal motion pattern is disc herniations, about 90% of which will occur at L4-L5 (lumbar segments 4 and 5) or L5-S1 (lumbar segment 5 and sacral segment 1 ). This is the most common occupational health problem in North America. In prior art documents, attempts have been made to solve the aforementioned drawbacks by different types of devices, which move the seat in order to facilitate getting in/out of a vehicle. It is known in the art to provide seats for adjustment which, having a floor engaging assembly, move backwards and forwards and upwardly and downwardly a minimum amount. There are also seats which swivel about an axis and a few which combine all of the features of up/down, back/forth, rotating and tilting movements. All these applications move the entire seat for adjustment purposes and are bulky and difficult to operate.

US 6,419,317 discloses a seat depth adjusting device for an automobile seat, which has a rear cushion part and a front cushion part movable relative to the rear cushion part for adjusting the depth of the vehicle seat. However this device does not specifically assist a person in getting in/out of a vehicle.

US 3,046,052 discloses a revolvable seat that can be rotated towards the door for ease of a person getting in/out of the vehicle. US 5,474,353 discloses a pivoting seat cushion arrangement for vehicle seat assemblies which is adapted to be mounted on the floor of a vehicle and a movable seat portion which is mounted on the fixed seat portion and adapted to be moved between a normal use or drive position and an access position where the front edge of the movable seat portion overlies the sill of the vehicle to facilitate egress from the vehicle. This patent also discloses a system for facilitating an individual's ingress into and egress out of the vehicle through a door opening of the vehicle comprising a vehicle seat assembly and a hand grip. Nevertheless such system requires the use of hand grips in order to try to prevent medical problems. Even with the use of hand grips the user needs to make a considerable effort so the risk of low back pain is not satisfactorily prevented since only pivoting movement and/or sliding movement are possible.

These devices relate to special seats, that is, part of the seat or even the entire seat of a vehicle must be replaced by a special seat. Moreover, sometimes these seats can only be arranged in special, usually large sized vehicles since the seat with the devices incorporated to move the seat and the free space needed for the person to move himself/herself make it impossible to install them in all kinds of vehicles.

There still exists in the art a need for a device to assist a person in getting in/out of a vehicle in order to prevent the medical problems mentioned above (such as LBP and disc herniations), which is easy to install and operates in the seats of any kind of vehicle, without the need for replacing part of the seat or even entire seat.

Summary of the Invention The present invention relates to an articulating device for assisting a person in getting in/out of a vehicle. Said device comprises articulating means placed between a cushion frame and a cushion of a seat of a vehicle for moving the cushion of the seat in a longitudinal direction towards the front of the seat and in a lateral direction towards an access door to the seat, and for moving the cushion with an upward movement suitable to obtain a reduction of the L4-L5 moment when the person gets in/out of the vehicle. Preferably the reduction of the L4-L5 moment is at least 30%.

The amount of the upward movement can be calculated according to the formula

M (Nm) = 0.015-x3 + 0.508-x2 + 4.4193-x + 16 wherein

M is the L4-L5 moment, x is the upward movement in mm.

Preferably the amount of the upward movement is at least 100 mm.

The seat and the cushion being a conventional seat or cushion. In the context of the present invention the term "conventional" refers to a seat or parts of a seat such as cushions, cushion frames and others that are typically mounted on a vehicle by the car manufacturer.

The articulating device can comprise:

- at least one four-bar linkage, the cushion frame of a seat being the fixed part and the cushion of said seat being the coupler link, joined together by two rigid bars to form the four-bar linkage;

- a linear actuator fixed to the cushion frame and the cushion for actuating the four-bar linkages, and

- a tie rod fixed to the cushion frame and the cushion, transverse to the movement of the four-bar linkages, whereby the linear actuator is actuated to move the cushion with the upward movement (in a vertical direction) and in the lateral direction towards the access door of the vehicle, and the tie rod is actuated to move the cushion in the longitudinal direction towards the front of the seat, so that it facilitates getting in/out of the vehicle.

The articulating device can comprise two four-bar linkages one in the front and one in the rear of the device.

In one embodiment the rigid bars of the four-bar linkage on the side closer to the access door are shorter than those on the opposite side, whereby operation of the articulating device makes the cushion tilt slightly towards the access door to further facilitate getting in/out of the vehicle.

Moreover, the present device is easy to install under the cushion of a conventional seat of a vehicle, therefore it does not require the replacement of the conventional cushion or seat for a specific one.

Brief Description of the Drawings

The present invention will be better understood by reference to the following drawings illustrating a preferred embodiment of the invention, provided by way of example, and should not be construed as limiting the invention in any way.

Figure 1 is a front view of a seat including a preferred embodiment of the device of the present invention.

Figure 2 is a perspective view of the seat including the device of Figure 1.

Figure 3 is an enlarged front view of the device shown in Figures 1 and 2.

Figure 4 is a graph showing the lumbar stress when getting out of a vehicle and the reduction of this stress by using the device of the present invention.

Figure 5 shows the lumbar area L4-L5 of the body at the getting out position.

Figure 6 is a graph showing the reduction of L4-L5 moment in function of the upward movement of the cushion of the seat.

Figures 7 and 8 schematically show the position of a driver in a sitting position and getting out of a vehicle, respectively.

Detailed Description of the Preferred Embodiment

According to the present invention, when a user wants to get out of a vehicle, the cushion rises up to a determined position (as will be explained hereinbelow) and it simultaneously moves laterally towards the access door of the vehicle and longitudinally towards the front of the seat. Once the user has gotten out of the vehicle the cushion performs the opposite movements, so that it goes back to a resting position in the seat of the vehicle.

When a user wants to get in the vehicle, he/she will perform the opposite movements. First, the device moves the cushion upwardly and towards the access door of the vehicle and the front of the seat to make it easier for the user to sit on it, and then moves back to a resting position on the seat of the vehicle.

Due to the combination of these three movements the device of the present invention helps to reduce the lumbar stress of a user getting in/out of the vehicle and can therefore prevent back problems such as LBP and disc herniations. The preventive effect of the present invention will be further explained hereinbelow in reference to Figure 4.

The present invention relates to an articulating device for assisting a person in getting in/out of a vehicle comprising articulating means placed between the cushion frame and the cushion of a conventional seat of a vehicle for moving the cushion with an upward movement, in a longitudinal direction towards the front of the seat and in a lateral direction towards an access door.

Figures 1 and 2 show front and perspective views, respectively, of a device according to one embodiment of the present invention installed in a seat of a vehicle. Said device, which is attached to the cushion frame 5 of a seat of a vehicle (in this case, for example it is the driver's seat of the vehicle), is mobile so that it moves the cushion 1 of the seat a calculated amount in the three directions (x, y, z) in order to facilitate getting in/out of the vehicle. Figure 2 shows in more detail the device of the present embodiment connected to the cushion 1 and the cushion frame 5. As can be seen in this Figure, the device has two four-bar linkages 2 (one in the front and one in the rear of the device) which are actuated by a linear actuator 3. As is well known to those skilled in the art, a four-bar linkage consists of a fixed part, a coupler link movable with respect to the fixed part, and two rigid bars connecting the fixed part to the coupler link. In this case, the fixed part is, or is attached to, the cushion frame 5 and the coupler link is, or is attached to, the cushion 1. The joints between the rigid bars and the fixed part allow for a movement of the rigid bars in the three directions (x, y, z). For example, the joints can be ball joints or any other kind that allows said three dimensional movement.

Said linear actuator 3 is fixed to the cushion frame 5 on one side of the seat, and to the cushion 1 on the opposite side of the seat. A tie rod 4 is fixed to the cushion frame 5 in the front of the seat and to the cushion 1 in the rear of the seat. Said tie rod 4 is thus transverse to the movement of the four-bar linkages 2.

The operation of the present device will be described in reference to Figure 3, which shows an enlarged view of the device described in reference to Figures 1 and 2. When the linear actuator 3 is actuated, it raises the cushion 1 with an upward movement and moves it in a lateral direction towards the door. At the same time, the tie rod 4 moves the cushion 1 in the longitudinal direction towards the front of the seat. The combination of these movements in all directions (x, y, z) makes it easier for the user to get in/out of the vehicle.

In a preferred embodiment, as shown in Figure 1 , the rigid bars of the four-bar linkage 2 on the side closer to the access door are shorter than those on the opposite side. In operating the articulating device according to this embodiment, the cushion (5) tilts slightly towards the door to further facilitate getting in/out of the vehicle.

The articulating means can be any means that allow performing the aforementioned movements including pneumatic or hydraulic means that incorporate racks and pinions, screw-nut actuating mechanisms, driving motors and the like. Nevertheless, in a preferred aspect of the present invention the articulating means are four-bar linkages due to their low cost, light weight and reduced size that allow being incorporated in a conventional seat. As can be seen from the previous Figures, the present device is very easy to operate and can be installed in any kind of seat for vehicles, without requiring the replacement of the entire seat since it is incorporated below the cushion.

Now, the effect of the present device to prevent the medical problems mentioned hereinabove will be discussed. As previously described, most of the problems related to the loss of normal spinal motion pattern occur at L4-L5. The lumbar stress in segments 4 and 5 can be:

• L4-L5 Moment - A load moment is created at about L4-L5 by forces due to the mass of the body. To maintain stability, or static equilibrium, the human body must actively resist the load moment created by these forces by activating his/her trunk muscles. This resistive moment is referred to as the support moment;

• L4-L5 Compression - L4 and L5 vertebrae are compressed together by the forces due to the mass of the body and the trunk muscles/ligaments that are used to generate the support moment;

• L4-L5 Reaction Shear - The forces due to the mass of the upper body create shear forces at the L4-L5 joint, or

• L4-L5 Joint Shear - In addition to the shear force created by the mass of the upper body and the forces acting on the hands

(reaction shear), a shear force is produced by the supportive trunk tissues (muscles and ligaments). The L4-L5 Joint Shear represents the resultant shear force due to the sum of the reaction shear and the muscle/ligament shear. It is this value, which includes the effect of muscle/ligament forces, which represents the actual shear experienced at the L4-L5 joint. In a preferred aspect of the present invention the L4-L5 Moment is used in order to ascertain the preventive effect of the present device, consisting of reducing the peak stress produced in the lumbar area due to the sequence of movements when getting in/out of a vehicle since it directly reduces the other abovementioned stresses. Nevertheless, it should be understood that the Compression, Reaction and/or Joint shear could also be used to determine the reduction of the peak stress indicating the preventive effect of the present device. In Figure 4 a graph can be seen that plots the L4-L5 moment in the different positions when getting out of a vehicle. Obviously, the moment when getting in a vehicle will be similarly reduced by the present device. The blue line represents the actual L4-L5 moment, whereas the pink line represents the target L4-L5 moment. As can be seen, the target achieved by the present device is a 30% reduction of the maximum L4-L5 moment, which occurs in position 4 in the graph. This target is obtained by moving the cushion of the seat a calculated amount with an upward movement.

Figure 5 shows the position of maximum lumbar stress which corresponds to that of a person getting in/out of a vehicle.

The necessary amount to upwardly move the cushion of the seat in order to reduce the maximum L4-L5 moment by 30% is calculated according to the following formula:

M (Nm) = A-x3 + B-x2 + C-x + D

wherein

M is the L4-L5 moment, x is the vertical movement measured in mm,

A, B, C and D are coefficients obtained calculating the following by ergonomic computer applications: - L4-L5 compression

- Body load compression

- Axial twist compression

- Flexion/extension compression

- L4-L5 joint shear - Abdominal force

- Abdominal pressure

CATIAV5 software has been used to calculate the previous coefficients from virtual simulations of getting in and getting out sequences. Thus, the final formula used to calculate the L4-L5 moment is:

M (Nm) = 0.015-x3 + 0.508-x2 + 4.193-x + 16

Figure 6 plots the reduction of L4-L5 moment in function of the upward movement of the cushion of the seat according to the previous formula. The shadow area represents the stress absorbed by the device when moving the cushion 100 mm upwardly, which represents a 30% reduction of the stress (L4-L5 moment) felt by the user's back. This upward movement of 100 mm (and therefore a 30% reduction of the lumbar stress) is considered to be the optimal amount of movement for this application. However, other amounts can obviously be used and will provide other reductions of the lumbar stress. Figure 7 shows a driver sitting in the seat of a vehicle in a resting position. Figure 8 shows the movement the driver has to make in order to get out of the vehicle. The position shown is that of maximum lumbar stress, which over time can give rise to LBP and other such medical problems. The device according to the present invention prevents these problems by raising the user up to that position, and therefore allowing him/her to get in/out of the vehicle without going through that position of maximum lumbar stress.

The above is a description of a preferred embodiment of the present invention, but other embodiments are also possible. For example, in the preferred embodiment the device comprises two four-bar linkages. However it may also have one four-bar linkage, or more than two four-bar linkages, without modifying the functionality of the device.

Although the present invention has been described in reference to a preferred embodiment, other embodiments will be apparent to those skilled in the art that fall within the scope of the present invention, limited only by the following claims.