Advanced seatbelt apparatus

A vehicle seatbelt apparatus includes a seatbelt web wrapped in a reel around a motor-rotated shaft. A latch is selectively engageable with the reel to lock a seatbelt retractor from movement in one direction while allowing movement of the retractor under motor rotation of the shaft in response to pre-crash vehicle braking deceleration, a vehicle downhill angle or a vehicle lateral “g” force exceeding a threshold. When a retractor locked position is detected, the motor is activated to retract the seatbelt web for a predetermined time period to urge the passenger toward a center upright position in a vehicle seat.

BACKGROUND

The present advanced seatbelt system relates, in general, to vehicle seatbelt systems.

Many passenger vehicles are equipped with an ELR (Emergency Locking Retractor) or ALR (Automatic Locking Retractor) type seat belts. Both types of seatbelts latch when vehicle brakes or the vehicle is in a steep downward or upward angle such as when driving downhill or uphill, or in a sharp or high speed turn with high g-levels. The seatbelt is usually latched at a 0.2-0.5 g level of deceleration.

Both seatbelt systems employ a motor driven retractor, which retracts the seatbelt webbing from a pulled-out position toward the original, retracted, non-use position. A motor drives the shaft which carries one portion of the seatbelt in a wind-up reel. A latch mechanism, such as a tooth wheel and lever arrangement or a rack and pinion gear arrangement is coupled to the seatbelt retractor to lock the seatbelt from further extensions.

Seatbelt pre-tension systems are employed using a high force element, such as an air cylinder, explosive charge, etc., to lock the seatbelt from further extraction during a crash or collision event. Such pre-tensioner systems are responsive to a vehicle electronic control unit which uses information from vehicle mounted crash sensors to detect an actual crash event.

Such seatbelt pre-tensioners are employed to prevent further forward movement of the passenger toward the airbag during a crash event so that the passenger is positioned at a proper distance for airbag deployment.

However, it is common for a passenger or the vehicle driver to not be centered in an upright seated position in the seat. Drivers and passengers slouch, lean to one side or the other, lean forward or back for comfort, or when the car is experiencing high g-levels during sharp or high speed turns, or is driving at a steep downhill angle.

What is needed to insure proper airbag deployment effectiveness is a seatbelt system which moves the driver or passenger toward a center upright seated position in a vehicle seat prior to the start of an actual crash event.

SUMMARY

An advanced seatbelt apparatus and method of operation are disclosed which under pre-crash condition, retracts the seatbelt to move or shift the position of a user of the seatbelt toward a thinner upright position in a vehicle seat.

A seatbelt apparatus comprising a seatbelt mounted in a vehicle, a motor driven retractor coupled to the seatbelt for retracting the seatbelt onto a reel from a pulled out position, a latch coupled to the reel and movable from a first position spaced from the reel allowing free unwinding of the seatbelt from the reel and a second latched position locking the reel from further unwinding of the seatbelt from the reel, the latch, when in the second position, allowing winding movement of the reel to retract portions of the seatbelt onto the reel, a detector positioned to detect movement of the latch to the second position latching the reel from further unwinding of the seatbelt, and an output of the detector coupled to a motor for energizing the motor to partially retract the seatbelt from the pulled out position to change a portion of a user of the seatbelt in a vehicle seat.

The latch may include a claw normally spaced from teeth on the latch. The claw is coupled to a movable bead. The bead moves to a second position upon predetermined deceleration level or downhill angle of the vehicle or sideways directed “g” forces exceeding a threshold to engage the claw with the teeth on the latch and lock the seatbelt in the pulled out position.

The bead can be mounted on a surface and capable of longitudinal and lateral movement relative to the surface.

The detector can include a limit switch or a Hall-effect sensor or an optical sensor.

A method of operating a vehicle seatbelt is disclosed where a portion of a seatbelt is wound in a reel around a motor-rotated shaft. The method includes detecting one of a pre-crash braking deceleration, a downhill vehicle angle and a sideways vehicle “g” force above a threshold, and retracting the seatbelt for a predetermined period of time to urge the passenger enveloped by the seatbelt toward a center upright position in the vehicle seat.

In the method, the detecting step includes a sensor having an element movable in response to pre-crash braking deceleration, a downhill angle and a sideways vehicle “g” force. In response to the output of the sensor, the method activates the motor.

In the method, includes providing a toothed wheel on a shaft coupled to a motor, mounting a pivotal claw in relation to the toothed wheel so that the claw is removable from a first rest position where a tip of the claw is spaced from the toothed wheel allowing free bi-directional rotation of the toothed wheel to a latched position where the tip of the claw engages one of the teeth on the wheel and locks the wheel from movement in one rotational direction, when a movable bead engaged with a surface contacts the claw, the movable bead moving in a direction to pivot the claw to engage the tip of the claw with the toothed wheel under inertial forces exerted by braking deceleration, downhill vehicle angle, and a sideways vehicle “g” force.

DETAILED DESCRIPTION

Referring now toFIGS. 1-4, there is depicted an advanced seatbelt system utilizing a seatbelt apparatus and method of operation which causes a short duration retraction of the seatbelt to move the passenger captured by the seatbelt toward a center up-right position in a vehicle seat prior to the occurrence of an actual collision event.

FIG. 1depicts a typical vehicle driver side seatbelt10which is representative of a front seatbelt employed in a vehicle. The seatbelt10includes a continuous web19which has a portion wrapped in a reel around a rotatable shaft driven by a retractor20. A vertically extending portion12extends from the reel on the retractor20through a clip18pivotally mounted on the vehicle door pillar. A chest portion14of the web19extends from the clip18through a tongue16which is releasably engageable with a buckle17fixed to the vehicle floor. A lap portion15of the seatbelt10extends from the tongue16to the reel in the retractor20.

The retractor20allows the seatbelt web19to be extended away from the vehicle seat to allow the passenger to wrap the chest portion14and the lap portion15over his or her chest and upper legs until the tongue16can be securely engaged in the buckle17. The retractor20is capable of retracting the web19to take up any slack which may exist in the seatbelt10so that the chest portion14and the lap portion15are snugly engaged across the passenger's chest and upper legs.

Both types of ELR and ALR seatbelt systems employ a motor driven retractor20which retracts the seatbelt10web19from a pulled out position back to an unused position. The motor driven retractor20drives a shaft24which carries one portion of the seatbelt10in a wind up reel. A latch22, shown inFIGS. 2 and 3, is mounted on the shaft24and rotates with the shaft24.

The latch22may be any latch used in vehicle seatbelt systems, including a rack and pinion gear latch, or the toothed wheel latch shown inFIGS. 2 and 3by example. The toothed latch22includes a rotatable disk-shaped wheel21fixedly mounted on and rotated with the shaft24. A plurality of circumferentially arranged, spaced teeth23are formed on the peripheral of the wheel21. Each tooth23is formed with a circumferentially extending, angled surface25which is separated from adjacent angled surfaces25on adjacent teeth23by a radially outward extending shoulder27.

As shown inFIGS. 2 and 3, the angled surfaces25are oriented in the same direction relative to the shaft24, the purpose of which will be described hereafter.

The latch22also includes a claw26in the form of a pivotally mounted lever having a tip31which is shaped to engage one tooth23on the wheel21at the juncture of the shoulder27and the angled surface25of a tooth23. The tip31of the claw26is positioned so that once the tip31engages a tooth23on the wheel21, further rotation of the wheel21in one direction, such as counter clockwise in the orientation of the wheel21and teeth23shown inFIGS. 2 and 3, is prevented. At the same time, an extension force by the driver on the seatbelt10to unwind the seatbelt10from the reel is permitted since the tip31of the claw26will ride around successive angled surfaces25of successively arranged teeth23on the wheel21.

The claw23has a bottom recessed surface33which is engaged by a rotatable element or member, such as a ball or bead28. The bead28rides within the recess in the surface33of the claw26as it moves along a fixed surface29. Except for the engagement with the bottom recessed surface33of the claw26and the surface29, the bead28is otherwise unattached to surrounding structure and is freely movable in response to vehicle motion, angular orientation, etc., as described hereafter.

Movement of the bead28from a first rest position shown inFIG. 2to a forward located position shown inFIG. 3is caused by inertial forces acting on the bead28by sudden braking deceleration of the vehicle above a threshold deceleration level. This deceleration creates inertial forces acting on the bead28causes the bead28to roll in a forward vehicle direction along the surface29forcing the bottom surface33of the claw26in an upward direction about its pivot point to move the tip31of the claw26toward the teeth23on the wheel21.

When the bead28has moved sufficiently forward, as shown inFIG. 3, the tip31of the claw26is in a position to engage a tooth23on the wheel21latching the wheel21and the retractor20in a fixed position preventing further unwinding of the seatbelt10from the retractor20.

It will be understood that forward motion of the bead28can also occur when the vehicle encounters a steep downhill angle. Gravity then acts on the bead28to pull the bead28to the forward position shown inFIG. 3.

The bead28can also move out of the recess and along the surface29under a lateral “g” force as might occur during a high speed turn, where the “g” force exceeds a threshold level.

A shallow recess may be formed in the surface29at the normal rest position of the bead28shown inFIG. 2. Such a recess will create a threshold force which must be exceeded by gravity or inertial before the bead28can begin its movement from the rest position for the forward vehicle position.

InFIG. 2, for normal vehicle operation, the tip31of the claw26is spaced from the teeth23on the wheel21since the bead or ball28is in the rest first position. However, upon inertia movement of the bead28, as shown inFIG. 3, when the predetermined deceleration level is imposed on the vehicle, or a steep downward driving angle or sideways directed g forces are exerted on the head28, the bead28changes position and pivots the claw26to bring the tip31into engagement with one tooth23on the latch22to lock the seatbelt10in a fixed position.

Regardless of different types of latching mechanism designs, the latch22status can be detected using a direct contact or a non-contact sensor or switch30, which is then used as a switch to activate an electric motor to retract the seatbelt10. This can be very effective to provide better protection for occupants from pre-crash or sudden maneuvers.

The electric motor will be activated once the latch status is detected as latched to remove the slack of the seatbelt10.

The switch30can be contact between the claw tip31and the wheel21or by detecting changes in magnetic field strength (e.g.; a Hall effect sensor) or an optical sensor, or a limit switch based on the position of the claw26.

Once the switch30is ON, electric power activates the motor49for a predetermined period of time regardless of subsequent switch status after the initial “ON” start signal in order to allow a determined amount of belt slack to be removed from the seatbelt10.

Once this cycle is complete and the switch status changes to “OFF”, the system resets the motor to release from the seatbelt locking mode and the motor will return to its original mode.

This system operates based on vehicle deceleration from braking, sudden maneuvers or by the angle of the vehicle body, etc. and it is an independent system that does not require CAN communication with other ECU's in the vehicle. This is a low cost system that can be easily adapted to the vehicles without requiring many changes to the vehicle electrical architecture.

An optional clutch, not shown, may be provided on the retractor20to temporarily disengage the motor from the shaft24to allow the passenger to freely extend the seatbelt10from the reel on the retractor.

Referring now toFIG. 4, a flow chart is depicted showing the method of operation of the retractor20and the latch22according to the present seatbelt apparatus.

When the vehicle brakes in step60or on a steep downhill angle or experiences a high sideways g force, an electronic control unit mounted on the vehicle, which may be in the form of a processor executing control instructions stored in a memory, determines if the vehicle deceleration from braking on the downward angle or the g force is greater than a threshold level to activate the retractor20in step62. If the vehicle deceleration downhill angle, or g force level is less than the threshold level, control moves to step64which returns to a normal seatbelt mode of operation.

However, if the vehicle deceleration, downhill angle, or g force is greater than the threshold level as determined in step62, the latch22locks the retractor20in step66by engagement of the tip31of the claw26with one of the teeth23on the wheel21. When the switch30is “ON” in step67, the switch30output activates the motor47in step68for a predetermined time period. Activation of the motor47rotates the shaft24in a direction to wind portions of the seatbelt10, such as the web portions12and15shown inFIGS. 2 and 3, onto the reel thereby exerting forces on the passenger to urge the passenger toward a center, upright position in the vehicle seat more suited for airbag deployment.

After the predetermined time period expires, the motor47turns off in step72and returns to a normal seatbelt mode of operation in step64.

It will be understood that the above sequence of operation described inFIG. 4applies equally to a severe downhill angle or sideways angle as would be exerted on the bead28to a high G turn or movement of the vehicle down a steep road.

The apparatus detects the locking status of the latch by adding a simple switch as opposed to a complicated ECU design. The switch need only detect ON and OFF states as opposed to continuously monitoring the level of contact.

The apparatus is independent from any ECU on the vehicle CAN bus and therefore does not require any complicated CAN communication with other ECUs in the vehicle. Some motorized seatbelts that have been recently introduced require communication with other ECUs in the active safety system, such as radar/camera/lidar, while the present apparatus only reacts to vehicle deceleration, vehicle angle and lateral “g” force.

The present apparatus can be easily retrofitted to current production vehicles without causing any interruption of existing ECU operation.