BELT ARRANGEMENT
TECHNICAL FIELD
The present invention concerns an arrangement to facilitate putting on a seat belt.
TECHNICAL STANDPOINT
Safety requirements for vehicles of all types, but especially motor vehicles, have ιcreased over the years. This increase in safety consciousness has sometimes increased demands on improved safety systems such as seat belts. One improvement that has taken place is an integration of all seat belt anchor points into the vehicle seat, a concept called "belt-in-seat". A vehicle seat applying this concept for a four-point seat belt is illustrated in the Swedish patent application no. 9900649-6. One disadvantage of known belt systems, and in particular four-point seat belts, is that the user can feel uncomfortable putting it on, in particular in cold climates where heavy and restricting outdoor clothes can cause problems. Since experience has shown that a safety arrangement that is experienced as complicated to use risks not being used at all, the problem of attaining an easy-to-use belt system is just as important as the problem of attaining a safe belt system. In tests, four-point belts have proved to provide superior safety compared with conventional three-point belts that most passenger cars are equipped with today, as the strain on the body in a collision is more evenly distributed using a four-point belt.
Means of facilitating putting on mount a seat belt, so-called automatic seat belts, are themselves previously known together with conventional belts where the belt anchor points are arranged on the car body and where, for example, an arm lifts the belt forward towards the user, whereby the means is controlled by, for example, by closing the vehicle door. In known technology, however, an automatic seat belt is not arranged within the seat unit, whereby relatively complicated means are required outside the seat unit. Known technology does not either give any indication of arranging an automatic seat belt in combination with a belt where all anchor points are arranged in the seat.
ACCOUNT OF THE INVENTION
The object of the present invention is to attain a means of facilitating putting on a safety belt arranged in a vehicle seat. This solution is achieved with a means possessing the characteristics specified in Claim 1. To be precise, the invention concerns a means in a vehicle seat to facilitate putting on a seat belt, where the said vehicle seat comprises a seat and backrest and where all the anchor points of the said belt are integrated in the vehicle seat. The belt comprises of at least one belt strap, which in a position of rest is arranged along one side and the edge of the backrest. The upper free end of the belt has an anchor point in a belt guide arranged on the top of the backrest. The belt guide is arranged in a mounting so that the belt can be turned from its position of rest along the edge of the backrest to another position that is essentially perpendicular to the position of rest. The arrangement further comprises at least one electrically or mechanically activated sensor arranged inside or outside the seat, whereby a specific action of a user can activate the sensor arrangement. The belt guide is arranged to rotate when the said sensor arrangement is activated, whereby the rotation will make the belt available to the said user. The user's action can, for example, be to sit in the seat, insert the ignition key or close the vehicle door.
The present invention consequently constitutes a development of the car's interior comfort. As the belt due to this invention is presented to a person that has carried out the necessary action, not only an enhanced comfort for the belt user is obtained but also a psychological effect in the form of a reminder and an admonition to use the seat belt.
The seat belt according to the invention can be a conventional three-point belt but in an especially preferred embodiment of the invention, the belt is a four-point belt comprising two separate belt straps arranged on each side and along the respective edges of the backrest intended to be linked together for anchoring a user in the vehicle seat. The upper free end of each belt strap has anchor point in a belt guide pivot mounted on the upper part of the backrest, whereby each belt strap can be turned from a position of rest along the edge of the backrest to a position that is essentially perpendicular to the position of rest. The belt guide mounting can, for example, constitute a ball bearing or similar.
The belt strap is anchored to the seat with for example a belt tensioner that in a known manner keeps the belt strap taut along the side surface of the backrest when in rest position and allows the belt to be unrolled when in use. The belt can be locked when jerked using known technology found in conventional inertia reel belts.
The sensor arrangement can constitute an electronic sensor arrangement or a mechanical means. Activation of the said arrangement sends an impulse, electrical or mechanical, to a driver coupled to the pivoting belt guide/s on the top of the backrest, whereby each belt guide pivots in the bearing so that the belt strap moves in a direction towards the user. In the new position, the surface of the belt strap is essentially parallel with and in front of the backrest and consequently facilitates for the user to put on the belt. When putting on a four-point belt according to the preferred embodiment of the invention, the user's arms can be inserted between the belt and the backrest in the same manner as when putting on a backpack and lock the two belt straps together, suitably using a dynamic belt buckle in front of the body.
The sensor arrangement can constitute a pressure sensitive electronic sensor arranged in the seat cushion or backrest of the seat. Such a sensor can for example be of the type used to send an indication in the form of a flashing lamp and/or an acoustic signal to a person occupying a vehicle seat to put on the seat belt. In the present invention, the sensor instead sends an impulse to start an electric motor, which rotates the belt guide in the ball bearing so that the belt moves along an essentially quadrant shaped path towards the user.
Alternatively, the sensor arrangement can constitute a sensor arranged in connection with the vehicle's ignition switch or the vehicle's door lock. In the same manner as described above, the sensor activates an electric motor, which rotates the belt guide in the ball bearing so that the belt moves along the said essentially quadrant shaped path towards the user; preferably two electric motors, which rotate the belt guides in the ball bearings so that the belt moves towards the user.
In the case of a mechanical means, the sensor arrangement can constitute a pressure plate arranged in the seat cushion or backrest, which pressure plate when under load from a user is displaced and thereby acts on a mechanical motion conveying system, which can be arranged to rotate each belt guide so that the belt moves towards the user.
To further facilitate putting on the belt, a section of the belt strap starting from the upper anchor point can be contained in a conductive plastic that is charged when the arrangement is activated, whereby the belt strap lifts and arches to form a space between the belt band and the backrest. This uses the same principle as so-called shape memory alloy, i.e. the material is constructed of layers with different characteristics, whereby the layers react in different ways to the charge, as a result of which the change in shape of the casing is obtained.
FIGURE DESCRIPTION
Following describes examples of embodiments of the present invention with reference to annexed drawings without limiting its scope of protection. The annexed claims specify further the embodiments in a technical manner.
Fig. 1 shows a vehicle seat fitted with a four-point belt with all anchor points arranged in the vehicle seat and an electronic sensor arrangement in the seat cushion.
Fig. 2 shows a belt guide pivot mounted in a ball bearing. Fig. 3 shows a vehicle seat fitted with a four-point belt with all anchor points arranged in the vehicle seat and a mechanical sensor arrangement in the seat cushion.
Fig. 4 shows a side-view section of the vehicle seat according to figure 3.
Fig. 5. shows a vehicle seat with a mechanical sensor arrangement arranged in the backrest.
Fig. 6 shows a vehicle seat with a mechanical sensor arrangement in the seat cushion and a motion conveyance system comprising a cable.
Fig. 7 shows the belt strap contained in a casing of conductive plastic.
Fig. 8 shows the belt according to fig. 7 being put on, where the casing and the belt after the shape of the casing has changed being illustrated with dashed lines.
DESCRIPTION OF EMBODIMENTS
Figure 1 shows a vehicle seat fitted with a first preferred embodiment of the invention. The seat comprises a seat cushion (10) and a backrest (11), and is fitted with a four- point belt, where all the belt anchor points are integrated in the vehicle seat. The said four- point belt comprises two separate belt straps (12) arranged on each side and along each edge of the backrest, intended to be coupled together when anchoring a user in the vehicle seat. Each belt strap (12) is anchored to the seat with a belt tensioner (not shown), which holds the belt straps taut along the side surfaces of the backrest when in rest position and allows the belt to be unreeled when in use. From the belt tensioner, each belt strap (12) runs out of the seat through a pivot mounted belt guide (14) with an opening (15) for the belt to be run out, see figure 2. Each belt guide is pivot mounted in a circular ball bearing (16) arranged on the top of the backrest. Also other types of bearing can well be used. Two belt guides, one for each belt strap, are consequently arranged on the top part of the backrest. These are situated symmetrically on the top of the backrest in conjunction with the side surfaces of the backrest.
The ball bearings accordingly make the anchor points of each belt free to rotate and the direction of the belt can consequently be adapted to the build and movement of the user. Each belt guide is rotated by an electric motor (30), which can be arranged in a cartridge in the seat backrest in conjunction with the respective belt guide. In an alternative embodiment, the electric motor can instead be integrated with the belt guide (not shown). Each electric motor is preferably coupled to the car's internal electrical system. A vehicle seat of newer model is normally supplied with current from the car's internal electrical system in order to heat the seat, adjust the position of the seat, etc., and for that reason it is fairly straightforward to connect an electric motor in the backrest. As indicated in fig. 1, the seat cushion (10) in a vehicle seat is fitted with a pressure sensitive electronic sensor (40). The electric motor (30) is arranged to be started by an impulse sent by the sensor when it comes under load, whereby the electric motor is arranged when activated to rotate the belt guide (14) essentially 90° towards the user. The electric motor can preferably be fitted with a time delay relay in order to retain the belt guide in position for belt application for a certain period, for example 20 seconds, and then be activated. The electric motor can also be equipped with a circuit to repeat the rotation of the belt guide a certain number of times within a certain period. The sensor can preferably be of the type used to activate a signal in the form of a flashing lamp and/or an acoustic signal to a person occupying a vehicle seat to put on the seat belt. In an alternative embodiment to one described above, a pressure sensitive electronic sensor can instead be arranged in the seat backrest.
In other possible embodiments of the invention, a sensor arrangement can be arranged outside the seat and comprise a sensor arranged in conjunction with for example the vehicle's ignition switch or to the vehicle door locking system. Such designs are previously known in other vehicle applications, such as sensors for activating reminders to the user in the form of sound and/or light signals.
Figure 3 shows an alternative embodiment of the invention, where the sensor arrangement comprises a mechanical pressure plate (13) arranged in the seat cushion and where the rotation of pivoting belt guide (14) is generated by a mechanical linkage system. The said pressure plate is consequently affected by the weight of a user sitting in the seat. The pressure plate (13) is arranged in the seat cushion concealed by the seat upholstery and suitably located so that the weight of a person sitting in the seat affects the plate to maximum effect. The plate can be preferably arranged on a flexible, springy surface that allows the plate to be displaced downwards when a person sits in the seat and that regains its original form
when the weight is removed. The plate can alternatively be suspended from springs. When under load, the plate pressed down one free end of a first motion conveyance means (17), which at its other free end is rigidly connected to a second pivot-mounted motion conveyance means (18). The first motion conveyance means (17) comprises a projection from the said second motion conveyance means. The said projection makes an angle to the lengthwise direction of the second motion conveyance means and can for example comprise a rod or plate of rigid material. The load on the pressure plate (13) consequently causes rotation of the second motion conveyance means (18) in the direction shown by arrow A. The second motion conveyance means (18) is arranged essentially parallel to the top and side surfaces of the seat cushion and extends towards the part of the sat cushion located under the backrest. At the rear end of the second motion conveyance means (18) is arranged a first bevel gear ring (19), which interacts with a second bevel gear ring (20) arranged on a third motion conveyance means (21). The said third motion conveyance means (21) is arranged essentially perpendicular to the second motion conveyance means (18) and extends essentially vertically through the backrest from the seat cushion to the upper part of the backrest as shown in figure 4. The said second and third motion conveyance means comprises preferably rods. Through the gear link, the rotation of the second motion conveyance means (18) is conveyed to the third (21). At the bottom end of the third motion conveyance means is arranged a gear ring (22) that conveys the rotation to a pivoting belt guide (14) arranged in a ball bearing (16) on top of the backrest.
Figure 4 shows the said bevel gear arrangement. Preferably, the first gear ring (19) has a larger diameter than the second gear ring (20) in order to achieve the necessary gear ration for rotating the belt guide (14). A skilled person will realise that a further step-up will be required to the belt guide in order to achieve the necessary rotation of the belt guide. Figure 5 shows an alternative embodiment of the invention for the case of a mechanical sensor arrangement, where the pressure plate (130) is arranged in the seat backrest and is acted on by the force of a user leaning against the backrest. The plate (130) also in this embodiment is preferably arranged on a flexible surface. Alternatively, the plate can be supported on springs. When the force of a user leaning against the backrest acts on the plate, it is displaced backwards. Thereby, the plate acts on a first motion conveyance means (170) such as an eccentric body, which is rigidly connected to a rotating mounted shaft (180) that extends essentially vertically towards the upper part of the backrest. The displacement of the plate caused by this force will consequently make the shaft (180) rotate. The said rotation is conveyed to a pivoting belt guide (14) arranged in ball bearings on the top of the backrest via
a gear ring (220) arranged at the top end of the shaft (180). A skilled person will realise that a further step-up will be required to the belt guide in order to achieve the necessary rotation of the belt guide.
Figure 6 shows another alternative embodiment of the invention for the case with a mechanical sensor arrangement, where the motion conveyance means comprises a cable (31) or similar, which at its one end is linked to a pressure plate (13) arranged in the seat cushion" and at its other end is linked to the belt guide (14) arranged in ball bearings, whereby the belt guide (14) is spring-loaded in its direction of rotation in such a way that it tends to return to its original position. A displacement of the said pressure plate caused by the weight of a user acbordingly achieves a pulling motion on the cable that causes a determined rotation of the belt guide (14). When the load on the pressure plate (13) is removed, the belt guide will regain its original position of rest through the action of the spring.
In the case of a four-point seat belt, the mechanical designs described above apply to one of the two belt straps. Since the two belt straps are arranged symmetrically on each side of the vehicle seat, the seat is fitted with two symmetrically arranged devices as above with a common pressure plate arranged in the seat cushion or backrest.
In a preferred embodiment, the top part of the belt (12) starting at the belt guide (14) is contained in a stiff casing (23) of conductive plastic as shown in figure 7. The plastic is charged when the arrangement is activated. A suitable power source would be the car's internal electrical system, which in a known manner is used for example to heat the seat cushion, etc. The casing of conductive plastic is arranged to undergo a change in form when charged, whereby the belt strap through its change in form lifts and arches as shown in figure 8, so that a space (25) is formed between the belt strap and the backrest in order to facilitate for the user to put on the belt. The principle of achieving a change in form when charged is the same as for so-called shape memory alloy that returns to a determined position when charged. This is achieved by using layers of material with different characteristics, whereby the layers act in different ways to the charge and as a result, the material will undergo a change in form. To achieve this change in form of the casing (23) that makes the belt strap lift, the casing can be suitably bent and comprise two layers of material with different contracting characteristics when charged, where the upper layer, which comprises the convex side of the casing, will contract greatly when charged, while the lower layer contracts to a lesser degree or not at all. When charged, the bent casing will consequently tend to straighten, whereon the belt strap will lift.
The embodiments described above should be regarded only as examples of the invention. A skilled person will find a number of embodiments within the framework of the invention as it is defined in the claims.