Patent Description:
In general, seatbelt usage reduces the probability of injury to occupants in a motor vehicle in the event of an accident. Nonetheless, there are occupants who do not wear a seat belt when traveling in a motor vehicle. Therein, two groups of occupants could be identified, which tend to be more likely not wear seat belts. One of these groups is children in a certain range of ages who are able to unbuckle themselves, but still act irrationally. The other group is obese occupants, wherein some of the factors contributing to a lower rate of usage are discomfort reaching the buckle and latch as well as discomfort reaching the seat belt buckle in order to unbuckle.

In order to overcome these disadvantages, buckle presenters are known which are able to move the buckle head temporarily in a more favorable position to insert the belt tongue. As a drawback, said buckle presenters are associated with high costs.

Further on, belt extenders are known. Occupants can insert these belt extenders as a second seat belt buckle at the top of the seat belt buckle. Thereby, a higher position of the seat belt buckle is achieved which is more comfortable for obese occupants. To prevent children from unbuckling themselves, belt extenders having a second seat belt buckle are known, which do not provide an easy-to-use push button to eject the seat tongue. These belt extenders are difficult to take into account in a design of the restraining system and therefore may prevent the restraining system from working as intended.

From <CIT> a seat belt buckling assistance and automatic release of the seat belt is known, wherein the buckle further includes a manual release element. Said document discloses the preamble of claim <NUM>.

<CIT> discloses an electrically releasable buckle assembly, wherein a shape memory alloy component is operatively coupled to the release button. Heating of the shape memory alloy component to or above a transition temperature moves the release button from the latched position to the release position.

Another buckle assembly is known from <CIT>, wherein the buckle comprises a manual release button and a remote release mechanism, including a buckle release cable and a module operably connected to the cable.

Considering this background, it is the task of the invention to provide an improved seat belt buckle, an improved restraining system and a method to control the restraining system which overcome the aforementioned disadvantages and are cost-efficient.

To solve the task of the invention, a seat belt buckle comprising the features of claim <NUM> is proposed. Further preferred embodiments may be obtained from the sub-claims, the figures, and the related description.

A seat belt buckle for a restraining system of a motor vehicle is proposed that comprises a housing, an insertion slot for the insertion of a belt tongue, and a push button. The push button is displaceable, preferably along a displacement axis, in the housing between a default position and a releasing position for releasing the belt tongue. It is proposed that the seat belt buckle comprises an electric actuator, which is adapted to move the push button from the default position to the releasing position, and/or to move a locking element of the seat belt buckle from a latched state to an unlatched state, and/or to lock and unlock the push button in the default position, and/or to lock and unlock the locking element in a latched state.

The electric actuator of the seat belt buckle is preferably able to move the push button so that a locked belt tongue is unlocked and/or ejected. In general, releasing a belt tongue in the seat belt buckle has the same effect as ejecting or unlatching a belt tongue from the seat belt buckle.

In a preferred embodiment, the push button is coupled to a locking element and/or a lock of the seat belt buckle so that the movement of the push button into a releasing position actuates the locking element and/or the lock in a position that unlocks a belt tongue.

In another embodiment, it is possible that the electric actuator directly actuates a locking element and/or a lock of seat belt buckle. In this case, the push button may stay in the default position or be moved into the releasing position when a seat tongue is unlocked and ejected by the electric actuator. It is also possible that the push button may be moved indirectly by the movement of the locking element when a seat tongue is unlocked by the electric actuator.

The seat belt buckle preferably comprises a frame or buckle channel, preferably made of metal, on which all or a share of the parts of the seat belt buckle are mounted. The electric actuator is preferably mounted on one or more motor mounts which motor mount(s) is preferably attached to the frame or buckle channel. The seat belt buckle is preferably enclosed by the housing, wherein the housing may have primarily a covering function. In possible embodiments, the housing can also have structural functions, in which all or a share of the parts of the seat belt buckle are mounted.

The electric actuator allows the belt tongue in the seat belt buckle to be released without the seat belt buckle having to be touched or reached by an occupant. This increases the comfort and ease of use of the seat belt buckle.

A locking element preferably engages with a belt tongue in a latched state so that the belt tongue is secured in the seat belt buckle. Further, the locking element can be another part of a locking mechanism in a seat belt buckle that directly or indirectly effects the releasing or locking of a belt tongue. In order to release a belt tongue, it is necessary to move the locking element out of the latched state into an unlatched state. In the unlatched state of the locking element the belt tongue is not fixed in the seat belt buckle. In general, the push button in the release position directly or indirectly moves a locking element to an unlatched state, and a locking element is preferably in a latched state when the push button is in a default position. Locking a locking element in a latched state inhibits the function of the push button so that a belt tongue cannot be released, not even with the push button. The locking element has to be unlocked first before the locking element can be actuate to an unlatched state.

Additionally or alternatively, the electric actuator in the seat belt buckle allows to lock and unlock the push button in the default position. Thereby, the push button can be blocked or held in the default position. As a result, a child, for example, is not able to de-latch the seat belt or to release a belt tongue from the seat belt buckle.

According to the invention, the seat belt buckle comprises a control rod, which is connected to the push button via a sliding connection, wherein the control rod can be actuated by the electric actuator.

The control rod and the sliding connection enable a favorable mounting position of the electric actuator and a good utilization of the given space in the seat belt buckle. The electric actuator is preferably mounted at the bottom of the seat belt buckle opposite the push button. This allows a small width of the seat belt buckle and is also favorable for the electrical connection of the electric actuator. The control rod can transmit a push and/or preferably pull from the electric actuator to the push button, resulting in a movement of the push button from the default position to the release position which leads to the release or ejection of a buckled belt tongue.

Preferably, the sliding connection has a first limit stop, wherein the control rod is adapted to move the push button from the default position to a releasing position when the push button and the control rod engage at the first limit stop.

The sliding connection enables a movement of the push button relative to the control rod and the electric actuator without moving the electric actuator. Thus, the push button can be pushed from the default position to the releasing position by an occupant without having to move the control rod and the electric actuator. The first limit stop of the sliding connection enables the control rod to engage the push button and to pull the push button towards the releasing position, while a manual push on the push button does not necessarily cause the actuator to move.

In in further development, it is proposed that the sliding connection has a second limit stop, wherein the control rod is adapted to lock the push button in the default position when the push button and the control rod engage at the second limit stop.

The second limit stop of the sliding connection can block the moveability of the push button and lock it in the default position when the control rod is moved to a position engaging with the second limit stop of the sliding connection. Actuating the control rod to abut at the second limit stop by the electric actuator allows to easily switch between a locked and unlocked state of the push button.

The combination of the sliding connection with the first and second limit stop allows to incorporate both functions, releasing the belt tongue and locking the push button, in single mechanism using a single electric actuator.

Blocking in the sense of the present invention also refers to significantly increasing the resistance or generating holding forces in the default position so that the push button can only be pressed towards the release position by applying a higher force than normal.

Preferably, the sliding connection comprises an elongated slot in the push button and the control rod comprises a control pin engaging in this elongated slot.

The control pin can be easily guided in the elongated slot and preferably interact at the first limit stop and/or second limit stop with the push button.

In preferred embodiments, it is proposed that the sliding connection extents parallel to the displacement axis. Thereby, any loads between the electric actuator and the push button can be transferred efficiently.

In an advantageous embodiment, the electric actuator is arranged in the housing. Thereby, the electric actuator is protected from the environment and the seat belt buckle can be mounted in a vehicle more easily.

In a further advantageous embodiment, the actuator is a rotational motor which is adapted to turn a lever which is connected to the control rod. A rotational motor as an actuator offers a cost-efficient and easy-to-control actuator. Preferably, the seat belt buckle comprises a gearbox arranged on the drive side of the actuator, preferably the rotational motor. Thus, smaller rotational motors with lower torque can be used in the seat belt buckle. A lever is preferably attached to the actuator, wherein further preferably a gearbox is arranged between the actuator, in particular rotational motor, and the lever.

Preferably, the control rod and the lever are rotatably connected, preferably by a connector pin. This allows an efficient assembly process while resulting in a sufficient bearing of the lever and the control rod.

Further, to solve the task of the invention, a restraining system for a motor vehicle with the features of claim <NUM> is proposed. The proposed restraining system comprises at least one seat belt buckle as described above and at least one seat belt with a belt tongue.

The proposed restraining system can provide multiple functions like electronically controlled releasing of a belt tongue out of seat belt buckle and/or locking the manual releasing to avoid misuse, for example by children.

According to a further development, it is proposed that the restraining system comprises an input means for receiving user input, preferably a switch and/or a sensor, and a control means for controlling the electric actuator, wherein the restraining system is adapted to eject the belt tongue out of the seat belt buckle and/or lock the belt tongue in the seat belt buckle based on the user input.

There are two groups of input means, contact type and noncontact type input means. Contact type inputs means can be switches of any kind and contact sensors, for example. Noncontact type input means can be contact-less sensors that capture voice input or gesture input, for example. The received user input is preferably processed by an electronic control means which controls the electric actuator of the seat belt buckle to operate according to the user input. Accordingly, the de-latch function can be actuated from any remote input means, for example a switch or sensor that can be installed in an ergonomic location to the occupant.

It is further proposed that the restraining system comprises a crash sensor for detecting a crash and a control means for controlling the electric actuator, wherein the restraining system is adapted to lock the belt tongue in the seat belt buckle based on a detected crash.

Thereby, any unintended release or unlatching of the seat belt, in particular the seat belt buckle, can be electronically avoided by the control means. In further developments, it is proposed to omit the inertia mass countering the mass of the push button to avoid unintended movement of the push button due to high accelerations, especially accelerations caused by a seat belt pretensioner. Thereby, an inertial de-latch lock can be created with the electric actuator.

Further, a method for controlling a restraining system comprising the features of claim <NUM> is proposed to solve the task of the invention. A method for controlling a restraining system as described above is proposed, characterized by the steps:.

In a preferred development, the following steps are proposed:.

A user input can be an input via switches or sensors which are comfortable for the user to operate. The switches or sensors can be arranged on a steering wheel, on a dashboard and/or door. Further, it is possible to detect a gesture as user input in a contactless manner or to detect any suitable voice command.

A vehicle condition sensor may be a crash sensor, for example. Further, a vehicle condition sensor preferably detects the ignition of the vehicle or the current speed of the vehicle as vehicle condition input.

As a safety measure, the seat belt buckle is preferably controlled to eject the belt tongue only when the user input and the vehicle condition input are in agreement. Thus, a release of the seat belt due to user input can be prevented in case a crash scenario is ongoing or the vehicle speed or vehicle acceleration are not favorable for ejecting the seat belt, for example. In these cases, the user input and the vehicle condition input would not be in agreement and the control means would not control the electric actuator to eject the belt tongue. In preferred embodiments, the vehicle condition input can be used to check the user input.

A vehicle emergency sensor can be a fire or heat sensor which generates a vehicle emergency input in case fire or extreme heat is detected. Further, a vehicle emergency sensor can be a water or pressure sensor detecting the ingress of water, resulting in respective vehicle emergency input. It also possible that the vehicle emergency sensor may detect any medical emergency of an occupant. Accordingly, the vehicle emergency sensor can be a vital sign sensor and/or a health monitoring sensor sensing the condition of an occupant. In case such a vehicle emergency input is detected the belt tongue can be released automatically, for example.

In another preferred development, the following steps are proposed:.

Once the crash is completed, the belt tongue in the seat belt buckle can preferably be unlocked again by the electric actuator. Thereafter, the seat belt buckle is ready for manual release or remote release with the electronic actuator.

In the following the invention shall be illustrated on the basis of preferred embodiments with reference to the accompanying drawings, therein shows:.

<FIG> shows a cross-section of an embodiment of a seat belt buckle <NUM> and a belt tongue <NUM>. The seat belt buckle <NUM> comprises a housing <NUM> and an insertion slot <NUM>, wherein the seat belt tongue <NUM> is inserted and locked in the latched state shown in <FIG>. The seat belt buckle <NUM> comprises a push button <NUM> that allows to release and eject the belt tongue <NUM>. The push button <NUM> is spring loaded and therefore remains in a default position <NUM> as shown in <FIG>. An occupant can de-latch and release the belt tongue <NUM> by pressing the push button <NUM> and moving the push button <NUM> from the default position <NUM> into a releasing position <NUM>, see also <FIG>. Accordingly, the push button <NUM> is displaced from the default position <NUM> along a displacement axis <NUM> to the release position <NUM>.

Various release mechanisms are well known in the art that result in release of the belt tongue <NUM> when the push button <NUM> is displaced to a release position <NUM>. The push button <NUM> may interact with an ejector <NUM> and a locking element <NUM> of the seat belt buckle <NUM> to release and eject the belt tongue <NUM>.

The seat belt buckle <NUM> comprises an electric actuator <NUM> that is mounted on two actuator mounts <NUM>. The electric actuator <NUM> is connected to a lever <NUM>, which is rotatably within a range preferably smaller than <NUM>°, further preferably smaller than <NUM>° by the electric actuator <NUM>. The lever <NUM> is rotatably connected to a control rod <NUM> which is arranged in parallel to the displacement axis <NUM>. The control rod <NUM> and the lever <NUM> are connected via a connector pin <NUM>, wherein the connector pin <NUM> extends through a hole of the control rod <NUM> and through an elongated hole of the lever <NUM>. Thereby, the control rod <NUM> can be kept in parallel to the displacement axis <NUM> over the range of motion of the electric actuator <NUM>. The control rod <NUM> extends towards the push button <NUM>, wherein a control pin <NUM> at the end of the control rod <NUM> and an elongated slot of the push button <NUM> form a sliding connection <NUM>.

The parts of the seat belt buckle <NUM> which enable a release of a belt tongue <NUM> based on an electric command to the electric actuator <NUM> are shown in <FIG> in an isometric view. As can be seen in <FIG>, a gearbox <NUM> is arranged between the electric actuator <NUM> and the lever <NUM>, so that the lever <NUM> can be provided with a higher torque in order to apply higher forces to the push button <NUM> via the control rod <NUM>. The electric actuator <NUM> is an electric motor in this embodiment. The push button <NUM> has an elongated slot <NUM> with a first limit stop <NUM> and with a second limit <NUM>. The first and second limit stop <NUM>, <NUM> are adapted to interact with the control pin <NUM> of the control rod <NUM> and provide limits to the sliding connection <NUM> in the directions parallel to the displacement axis <NUM>.

<FIG> shows a detail view of the push button <NUM>, wherein the first limit stop <NUM> is oriented towards the releasing position <NUM> and the second limit stop <NUM> is oriented towards the default position <NUM>.

<FIG>, <FIG> show different positions of the push button <NUM> and the control rod <NUM>.

In <FIG>, the push button <NUM> is in the default position <NUM> and a belt tongue <NUM> is locked in the seat belt buckle <NUM> by the locking element <NUM>. The control pin <NUM> rests against the first limit stop <NUM> of the elongated slot <NUM>. In this state, the push button <NUM> is held in the default position <NUM> by a spring (not shown) of the seat belt buckle <NUM> and the electric actuator <NUM> does not apply any forces. The push button <NUM> can be pressed by an occupant to the release position <NUM> of the seat belt buckle <NUM>, wherein the sliding connection <NUM> and the control rod <NUM> do not provide any significant resistance since the control rod <NUM> can be held stationary without engaging with a limit stop <NUM>, <NUM>. Thus, in this state the common functionality of the seat belt buckle <NUM> is unchanged.

<FIG> shows a cross-section of a seat belt buckle <NUM> with the push button <NUM> manually pushed towards the releasing position <NUM>. Thus, the electric actuator <NUM> is not active and the control pin <NUM> travels along the elongated slot <NUM> of the push button <NUM>. Accordingly, the push button <NUM> is not locked in this position of the control rod <NUM> and can be moved freely between the default position <NUM> and the releasing position <NUM>.

<FIG> shows a cross-section of a seat belt buckle <NUM> with the electric actuator <NUM> releasing a belt tongue <NUM>. The electric actuator <NUM> turns the lever <NUM> clock-wise and pulls the control rod <NUM>. The control pin <NUM> of the control rod <NUM> engages with the first limit stop <NUM> and displaces the push button <NUM> along the displacement axis <NUM> to the releasing position <NUM>. In the releasing position <NUM> the locking element <NUM> or latch is lifted and the ejector <NUM> pushes the belt tongue <NUM> out of the insertion slot <NUM>.

Further, in this preferred embodiment, it can be seen that an inertia mass <NUM> is lifted allowing the locking bar <NUM> to unlock the locking element <NUM> or latch and thereby releasing the belt tongue <NUM>.

<FIG> shows the cross-section of the seat belt buckle <NUM>, wherein the push button <NUM> is locked in the default position <NUM>. The electric actuator <NUM> and the control rod <NUM> block any movement of the push button <NUM> completely or provide significant resistance against the displacement of the push button <NUM> out of the default position <NUM>. As shown in <FIG>, the control pin <NUM> abuts the second limit stop <NUM> so that any movement of the push button <NUM> towards the releasing position <NUM> has to overcome the resistance of the electric actuator <NUM> and/or the gearbox <NUM>.

In other embodiments, the electric actuator <NUM> may be attached to other parts of the locking mechanism, for example the locking element <NUM>, of the seat belt buckle <NUM> in order to lock or disable the function of the push button <NUM> and/or the release a belt tongue <NUM> locked in the seat belt buckle <NUM>.

<FIG> shows a schematic view of a restraining system <NUM> for a motor vehicle. The restraining system <NUM> comprises a seat belt buckle <NUM> as described above and a corresponding belt tongue <NUM> attached to a seat belt <NUM>.

The restraining system <NUM> comprises an electronic control means <NUM> that controls the electric actuator <NUM> of the seat belt buckle <NUM>. Further, the restraining system <NUM> has an input means <NUM>, for example, switches. These switches can be operated by an occupant in order to electrically release the belt tongue <NUM> and/or to lock and unlock the push button <NUM> in the default position <NUM> to provide a child lock, for example. The same applies to other input means <NUM> like ultrasonic sensors, microphones, and/or touch sensitive sensors, for example.

Further, the restraining system <NUM> comprises a crash sensor <NUM> in this preferred embodiment. The control means <NUM> may command to lock or unlock the belt tongue <NUM> in the seat belt buckle <NUM> based on the input of the crash sensor <NUM>. When a crash is imminent or detected by the crash sensor <NUM> the control means <NUM> controls the electric actuator <NUM> to lock the push button <NUM> in the default position <NUM>. Further on, the crash sensor <NUM> may detect the end of the crash scenario and the control means <NUM> controls the electric actuator <NUM> to unlock the push button <NUM>.

In preferred embodiments, the restraining system <NUM> comprises a vehicle condition sensor <NUM>. The vehicle condition sensor <NUM> may detect the status of the ignition or a comparable status of a motor vehicle, and/or the speed of the vehicle.

Further on, the restraining system <NUM> illustrated in <FIG> comprises a vehicle emergency sensor <NUM>, which may detect fire, a similar hazard or water, i.e., drowning of the motor vehicle, and/or any medical emergency of an occupant.

The restraining system <NUM> of <FIG> may be controlled and operated in the following manner.

The control means <NUM> reads a user input from a user input means <NUM>, like a switch. The user input may be a command to activate or deactivate the locking of the push button <NUM> in the default position <NUM>, which can be used as a child lock of the seat belt buckle <NUM>. The activation or deactivation or the position of the control rod <NUM> may be controlled based on user input from the input means <NUM>.

Other user inputs like a command to release a belt tongue <NUM> may be cross-checked with input from a crash sensor <NUM> or a vehicle condition sensor <NUM> in order to avoid releasing the belt tongue <NUM> based on a false or unintentional input from an input means <NUM> during a phase of high acceleration or a crash. Accordingly, the seat belt buckle <NUM> is only de-latched when predefined conditions are fulfilled.

Further on, the control means <NUM> can be adapted to control the electric actuator <NUM> to release a belt tongue <NUM> from the seat belt buckle <NUM> without a user input from the input means <NUM>. Preferably, the restraining system <NUM> comprises a vehicle emergency sensor <NUM> adapted to detect emergency situations like fire or ingress of water, for example, which may trigger an emergency de-latching without a dedicated user input.

Claim 1:
Seat belt buckle (<NUM>) for a restraining system of a motor vehicle, comprising
- a housing (<NUM>),
- an insertion slot (<NUM>) for the insertion of a belt tongue (<NUM>), and
- a push button (<NUM>) displaceable between a default position (<NUM>) and a releasing position (<NUM>) for releasing the belt tongue (<NUM>), characterized in that
- the seat belt buckle (<NUM>) comprises an electric actuator (<NUM>), which is adapted
- to move the push button (<NUM>) from the default position (<NUM>) to the releasing position (<NUM>), and/or to move a locking element (<NUM>) of the seat belt buckle (<NUM>) from a latched state to an unlatched state,
and/or
- to lock and unlock the push button (<NUM>) in the default position (<NUM>), and/or to lock and unlock the locking element (<NUM>) in a latched state, wherein
- the seat belt buckle (<NUM>) comprises a control rod (<NUM>), which is connected to the push button (<NUM>) wherein the control rod (<NUM>) can be actuated by the electric actuator (<NUM>),
characterized in that,
the control rod (<NUM>) is connected to the push button (<NUM>) via a sliding connection (<NUM>).