CROSS REFERENCE TO RELATED APPLICATIONS The application claims the benefit of United States Provisional application, serial no. 60/577,546, filed June 7, 2004, the contents of which are incorporated herein by reference thereto.

The application also claims the benefit of United States Provisional application, serial no. 60/607,988, filed September 8, 2004, the contents of which are incorporated herein by reference thereto.

This application is also related to the following United States Patent Applications filed contemporaneously herewith: CHILD SEAT AND MONITORING SYSTEM, Attorney Docket No. DP-312733; CHILD SEAT MONITORING SYSTEM AND METHOD FOR DETERMINING A TYPE OF CHILD SEAT, Attorney Docket No. DP-312081 ; CHILD RESTRAINT SYSTEM AND METHOD FOR MONITORING INSTALLATION OF THE CHILD RESTRAINT SYSTEM, Attorney Docket No. 313039; CHILD RESTRAINT SYSTEM AND METHOD FOR MONITORING INSTALLATION OF THE CHILD RESTRAINT SYSTEM, Attorney Docket No. DP-312329; CHILD RESTRAINT SYSTEM COMPRISING WEIGHT SENSOR5 Attorney Docket No. DP-312079; CHILD RESTRAINT SYSTEM COMPRISING CONTROL UNIT FOR EVALUATING HARNESS ADJUSTMENT, Attorney Docket No. DP-312730. The contents of which are each incorporated herein by reference thereto.

TECHNICAL FIELD This present invention relates generally to child seats and restraint systems. More specifically, the present invention relates to a child seat with an apparatus for monitoring the state of a tether securing the child seat to a vehicle. BACKGROUND Usage of child and/or infant seats in vehicles has become commonplace and in some situations legally required. Many child seats are secured to the vehicle by passing a seat belt through an opening or openings in the child seat, wherein the child seat or infant seat further comprises a seat belt restraint system for securing the child to the seat. In addition, some child seats are equipped with adjustable tethers or straps fixedly secured to the child seat at one end and comprising a latch at the other end wherein the latch is clamped or engaged with a universal anchor point provided in the vehicle. These universal anchors or anchor points are located throughout the vehicle to provide an anchoring point for a tethering device or latching device for securing the child seat to the vehicle. The child seat is securely fastened to the vehicle when the latch of the tethering device is secured to the universal anchor and any excess slack is removed such that the tether has a minimum amount of tension.

Accordingly, it is desirable to provide a child seat with an apparatus that will monitor and provide an indication of the amount of tension in a tether or strap securing the child seat to the vehicle.

SUMMARY Disclosed herein is a device and method for monitoring and providing an indication of the amount of tension in a tether or strap securing the child seat to the vehicle.

In accordance with an exemplary embodiment a child seat adapted for use in a vehicle is provided. The child seat has a shell portion; an adjustable tether secured to the shell portion at one end and having a clasping portion at the other; a tension sensor for providing a signal indicative of a tension of the adjustable tether; and an electronic control unit secured to the shell portion, the electronic control unit being operably coupled to the tension sensor to receive the signal, the electronic control unit being capable of processing the signal to compare the signal to a signal indicative of a predetermined range of acceptable tension, wherein the electronic control unit provides an output indicating whether the tension of the adjustable tether is within the predetermined range.

A child seat adapted for use in a vehicle, the child seat comprising: a base portion; a carrier portion configured to restrain a child the carrier portion being removable secured to the base portion; an adjustable tether secured to the base portion having a pair of clasping portions disposed at either end, a tension sensor for providing a signal indicative of a tension of the adjustable tether; and an electronic control unit secured to the base portion, the electronic control unit being operably coupled to the tension sensor to receive the signal, the control unit being capable of processing the signal to compare the signal to a signal indicative of a predetermined range of acceptable tension, wherein the electronic control unit provides an output indicating whether the tension of the adjustable tether is within the predetermined range.

In accordance with another exemplary embodiment, a method for determining the tension of an adjustable tether of a child seat is provided. The method comprising: locating a tension sensor along a portion of the adjustable tether, wherein the tension sensor is configured to provide a signal indicative of a tension of the adjustable tether; receiving the signal of the tension sensor by an electronic control unit being operably coupled to the tension sensor and secured to a portion of the child seat; processing the signal to determine if the signal corresponds to a signal indicative of a predetermined range of acceptable tension; and indicating whether the tension of the adjustable tether is within the predetermined range by providing an output.

The above-described and other features of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims. DRAWINGS Figure 1 is a side elevational view of a child seat constructed in accordance with an exemplary embodiment of the present invention; Figure 2 is a side elevational view of a child seat constructed in accordance with an alternative exemplary embodiment of the present invention; Figure 3 is a side elevational view of another child seat constructed in accordance with an alternative exemplary embodiment of the present invention; Figure 4 is a schematic illustration of an electronic control unit constructed in accordance with an exemplary embodiment of the present invention; Figure 5 is a schematic illustration of a tension sensor contemplated for use with exemplary embodiments of the present invention; and Figure 6 is a flow chart illustrating portions of a control algorithm contemplated for use in exemplary embodiments of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Disclosed herein is a method and apparatus for monitoring and providing an indication of the amount of tension in a tether or strap securing the child seat to the vehicle. In accordance with an exemplary embodiment, the tension of the tether is provided to a control unit of the child seat wherein the control unit comprises an indicating means for providing a status of the tether tension. Non-limiting examples of the indicating means includes but are not limited to visual displays comprising light outputs, visual displays comprising indicia, audible text, audible chimes or tones and combinations of any of the foregoing.

The control unit can also be configured to receive signals from a plurality of sensors each being adapted to provide information relative to the child or infant seat to the control unit wherein the control unit will comprise an algorithm to interpret and provide an indication means relative to the center input.

Referring now to Figures 1 and 2, a child seat 10 constructed in accordance with an exemplary embodiment of the present invention is illustrated. Child seat 10 is configured to be secured to a seat 12 of a vehicle (not shown) by at least one adjustable securement tether 14, which is fixedly secured to the child seat at one end and comprises a latching device 16 at the other. Although only one adjustable tether is shown in Figure 1 it is contemplated that multiple adjustable tethers may be used. In accordance with an exemplary embodiment, latching device 16 comprises a hook or clasp 18 for securement to at least one universal anchor 20 disposed on or proximate to the vehicle seat. In accordance with an exemplary embodiment a lower portion of the child seat is equipped with the rigid anchor 22 while a top portion is equipped with a tether.

Referring now to Figure 2, an alternative child seat has at least one lower mounting tether or a pair of tethers 24 disposed at either side to secure a lower portion of the child seat to universal anchors disposed on either side of the vehicle seat. In other words a single lower mounting tether or a pair of mounting tethers are contemplated for use in exemplary embodiments of the present invention. Referring now to Figure 3, a rear facing infant seat 26 is illustrated. Infant seat 26 comprises a carrier portion 28 removably secured to a base portion 30. Base portion 30 is fixedly secured to the vehicle seat by an adjustable tether 32 comprising a pair of clasping portions 34 (only one shown) disposed at either end adjustable tether 32 for securement of the same to the vehicle via universal anchors 20. The base portion is intended to remain in the vehicle while the carrier portion is intended for transport of the child in vehicle as well as outside of the vehicle thereby allowing transport of the infant without waking him or her. Accordingly, carrier portion 28 securely couples to the base portion for transporting a child within the vehicle, but may be disengaged from base portion for carrying the child outside the vehicle. This infant seat is intended for infants from birth weight to weights of up to approximately 20-22 pounds or when the baby no longer fits within the carrier portion. Of course, it is understood that these ranges are provided as examples and the contemplated ranges may vary.

Referring now to Figures 1-3 and in accordance with exemplary embodiments of the present invention each child seat further comprises an electronic control unit 36. In accordance with an exemplary embodiment electronic control unit 36 is integral with a shell portion 38 of child seat 10 or base portion 30. Alternatively, electronic control unit 36 is configured to be inserted into a cavity of either the carrier portion or base portion.

In accordance with an exemplary embodiment and referring now to Figures 1-4, the electronic control unit will comprise a microprocessor 40, microcontroller or other equivalent processing device capable of executing commands of computer readable data or program for executing a control algorithm that receives signals from a plurality of sensors 42 and provide an output to a display 44 via visual and/or audio drivers, wherein ah indicator 46 of the electronic control unit is activated. In accordance with an exemplary embodiment, the electronic control unit is configured to have analog comparator circuitry for processing analog signals. In one embodiment analog comparator circuitry is provided as a stand-alone feature or in combination with other processing electronics.

In order to perform the prescribed functions and desired processing, as well as the computations therefore (e.g., the execution of fourier analysis algorithm(s), the control processes prescribed herein, and the like), the electronic control unit may include, but not be limited to, a processor(s), computer(s), memory, storage, register(s), timing, interruρt(s), communication interfaces, and input/output signal interfaces, as well as combinations comprising at least one of the foregoing. For example, the controller may include input signal filtering to enable accurate sampling and conversion or acquisitions of such signals from communications interfaces. As described above, exemplary embodiments of the present invention can be implemented through computer-implemented processes and apparatuses for practicing those processes.

In one contemplated embodiment the electronic control unit is adapted to receive signals transmitted thereto, one non-limiting example would be wireless radio frequency RF transmission or direct electrical communication via a wiring.

In order to ensure proper securement of the child seat to the vehicle seat via the adjustable tethers a minimum amount of tension must be present in the adjustable tethers when the child seat is secured to the vehicle. An exemplary range of acceptable tension is approximately 17-35 Newtons or approximately 3.8-8.0 pounds. Of course, it is understood that the aforementioned ranges are provided as non-limiting examples and these ranges may vary to be greater or less than the aforementioned ranges. In order to monitor this amount of tension a tension sensor 42 is positioned to detect the tension and provide a signal indicative of tension to the microprocessor. In accordance with an exemplary embodiment multiple sensors may be positioned in each of the tethers to provide signals to the electronic control unit. Non- limiting locations of the tension sensor are shown in Figures 1-3.

By measuring the tension in the tether it is now possible to detect improper installation of the child seat due to the tethers being twisted or misrouted; not being pulled taut once the clip(s) engage the universal anchors or the clip(s) may be attached to the incorrect anchor(s). By using a means to measure the tension on the adjustable tether, the vehicle driver can be alerted that there is a problem with the child seat installation. In accordance with an exemplary embodiment the monitoring device(s) or sensors are positioned at or about the attachment point of the adjustable tether to the child seat wherein the amount of tension on the tether(s) can be monitored. Alternatively, the tension may be monitored by placing the tension monitoring device(s) directly on or in-line with the tether(s) wherein the tether(s) tension may be monitored. In yet another alternative, the tension sensor would be located at the attachment point of clip(s), latching device(s), hook(s), rigid clamp, etc. to tether(s). In yet another alternative, the tension sensor may be placed on rigid anchor for example as in United States Patent No. 10/664,128, filed September 17, 2003, the contents of which are incorporated herein by reference thereto. In yet another alternative embodiment, the tension sensor may be embedded into the webbing of the adjustable tether.

Several technologies may be used to sense the adjustable tether(s) and/or anchor(s) tension load which may affect the most desirable location for the sensor, non-limiting examples include the point of contact between the tether and the shell wherein tension on the tether will move a magnet, depress a force sensor alternatively the sensor may be located at the tether to clasping portion interface wherein tension on the tether will move a magnet, depress a force sensor etc. in other applications force, strain sensors or Hall effect sensors and if applicable magnets may be disposed in the tether to sense the tension. Referring now to Figure 5 several sensor contemplated technologies are contemplated for use as a tension sensor; non-limiting examples include but are not limited to a spring-loaded Hall Effect sensor, a strain gage monitor, and an electro-mechanical switch. Examples of one such tension sensing assembly are found in United States Patent No. 6,749,038 the contents of which are incorporated herein by reference thereto.

One non-limiting example of such a sensing device is a magnetic member disposed in the tether and a Hall effect sensor (illustrated schematically as item 42 in Figure 1) positioned to sense the magnetic field of the magnet. Thus, when the magnet moves away the field changes and this is sensed by the sensor that provides an output signal. The Hall effect device will sense the strength of the magnetic field of the approaching magnet, and depending on the strength of the magnetic field, the Hall effect device will generate an electric signal (voltage or current), which can be used to determine the tension in the adjustable tether. For example, and in a non-limiting embodiment, the Vcc of the Hall effect sensor assembly is 5 volts +/- 0.5 volts DC. The voltage with no magnetic field present will be approximately 2.5v. As the magnet is brought into the proximity of the sensor, the voltage will increase to near Vcc or decrease to near ground, depending on the polarity of the magnet. Accordingly, as the voltage increases or decreases, so does the tension of the seat belt. Thus, the sensor can be calibrated to detect acceptable tension ranges. Of course, Vcc may have values greater than and less than 5 volts.

Programmable ASIC applications of Hall Effect sensors are known in the art which process the resultant signal from the varying magnetic field and output a corresponding analog voltage or digital data value. One non- limiting example of such a sensor is the HAL 18XX family of sensors from Micronas, which is described in the cited document entitled: HAL 18XX, Low- Cost Programmable Linear Hall-Effect Sensor, the contents of which are incorporated herein by reference thereto.

Alternatively, the device can be configured such that the magnet moves further away from the Hall effect device when the movable member is moved and the reduction in the magnetic field will be sensed by the Hall effect device. In either embodiment, the signal is received by an algorithm of the electronic control unit.

Although the use of a Hall effect device is described above it is also contemplated that other types of sensing devices may be used to sense movement and provide an output signal indicative thereof. For example, such alternatives include but are not limited to the following: magneto-resistor, magnetosensitive devices, anisotropic magnetoresistors, optical devices and equivalents thereof. Also, a magnetic flux deflector may be employed in lieu of a Hall effect device.

In embodiments wherein Hall effect devices are used the location of the magnets secured to the tether must be in close proximity to the Hall effect device so that movement can be detected.

In one non-limiting example, tension sensor 42 will comprise a housing 41 wherein a first portion 43 is secured to the child seat shell and a second portion 45 is movably anchored to the housing by a spring 47 at one end and the other end is secured to the harness tether wherein tension on the tether will cause movement of the second portion with respect to the first portion, wherein a magnet 49 is disposed on the second portion and a Hall effect device 51 is positioned on the first portion to detect movement of the magnet and provide a signal the electronic control unit. In one embodiment the spring constant can be calibrated to expand in accordance with acceptable tension ranges thus, upon application of a tension force in the acceptable range the spring will be overcome and the magnet will move away or closer to the Hall effect sensor. Non-limiting exemplary locations for housing 41 include but are not limited to being positioned between tether 14 and the child seat shell and/or between universal anchor 20 and the clasping device.

Another exemplary sensing device could be an actuator manipulated by the tether or a sensor disposed directly on the tether. Another contemplated sensor is a Standard A201 sensor available from FlexiForce. Further description of this sensor may be found in U.S. Patent No. 6,272,956, the contents of which are incorporated herein by reference thereto. Such a sensor could be disposed in the location illustrated schematically as item 42 in Figures 1-3. Another alternative location for the sensor for detecting the H

harness tether would be at a point of contact between the tether and shell. For example, a force sensor can be positioned at the point of contact between the tether and shell other than the point of securement of the tether to the child seat. In this embodiment, the tethers are positioned to make contact with the force sensor positioned at the appropriate position of the child seat where the applied force can be compared to an acceptable level of force, which will correspond to an acceptable tension in the tether. Such acceptable levels- of force will correspond to the angular position of the tether with respect to the shell and the point of contact. In addition, the tether may be coated with a coating at the point of contact to prevent wearing of the tether and allow for low factional resistance between the tether and the force sensor to allow for sliding while detecting applied force. Additionally, the force readings from the force sensors may each be used in an equation of the control algorithm in order to determine the harness tether tension.

In any of the aforementioned embodiments the sensor is configured to provide a signal to an electronic control unit coupled to the sensor, which comprises logic, comparators etc, and/or is adapted to provide additional signals upon receipt of a signal indicating the tether has a tension within an acceptable range.

In each instance, the sensing principle is the same, only the sensing technology is changing. The sensor monitors the tension load exerted by the adjustable tether webbing through the selected path, and/or the tension force exerted by the adjustable anchor (Figure 1). The sensor(s) may be either analog or discrete. An analog sensor will continuously monitor the normal force exerted by the adjustable tether webbing or at the rigid anchor base. By monitoring the sensor output, a flag condition may be set when the tension load force correlating to an appropriate installation cinch force is met. A discrete sensor will be calibrated to toggle the output status when the appropriate tension load force condition is met. The system controller will then input the signal into algorithm in order to determine if the received signal corresponds to a predetermined condition (e.g., tension or force on tether within an acceptable range), which would cause the controller to provide the indication means to the vehicle occupant. The algorithm may have a look up table of signals, which correspond to tensions and movements of the adjustable tether, which are compared to the signal received. The sensor communicates a signal electronically to the electronic control unit. The electronic control unit interprets the signal and processes it algorithmically to determine the tether status.

In accordance with an alternative exemplary embodiment the sensor signal may then be processed in the electronic control unit with other signals from a child seat for example a chest harness buckle switch sensor and/or a chest harness tension sensor of the restraint belts of the child seat. Accordingly, the electronic control unit can determine the status of all the sensors and make an appropriate determination whether the child is secured properly in the child seat or not. The electronic control unit then can provide an output to the driver such as "Insufficient adjustable Tension", "adjustable Installation OK", or "adjustable Sensor Faulted" as a result of performing internal electronic control unit and sensor diagnostics, such text read outs may be viewable on a liquid crystal display 48 of the display 44.

Each status indication can also be displayed as a series of LED/lights that are visible to the driver, or through a speech system, communicated by the electronic control unit, or alternatively communicated to the vehicle for display in the instrument panel as part of a display to the driver. In accordance with an exemplary embodiment a standalone sensing system with an internal power supply, such as a battery or kinetic device that derives its power from the motion of the vehicle is provided wherein the display is integral with the child seat. Alternatively, the system could plug into the 12V DC power of the vehicle. Referring now to Figure 6, a flow chart for portions of a control algorithm for determining the tension of at least one tether of a child seat is shown. At step 60, the electronic control unit initiates an evaluation of an adjustable tether tension. This may be in response to manipulation of an activation button 62 on the display of or coupled to the electronic control unit. At step 64, the electronic control unit receives an output signal from the tension sensor. At decision node 68, the electronic control unit compares the output signal to a value indicative of the predeteπnined tension limit for the adjustable tether associated with the tension sensor. In one exemplary embodiment, the output signal of the tension sensor is a voltage proportional to the tension of the tether and is compared to a voltage value corresponding to a signal that would be produced for an acceptable tension in the adjustable tether. Alternatively, a digital or binary output may be received.

In an exemplary embodiment, the electronic control unit is electrically coupled to the display that comprises the plurality of lights or LEDs 46, such as green lights, that confirm acceptable tension values in the adjustable tethers, and a plurality of lights or LEDs 70, such as red lights, that are illuminated in response to a signal indicating a tension outside of the predetermined range to provide a warning of an improperly installed child seat. In an non-limiting example the display will include indicia 72 identifying the adjustable tether wherein a green LED and a red LED are positioned adjacent to each other to provide an indication of whether the adjustable tether is installed properly by having a predetermined amount of tension.

Accordingly, and if the signal(s) is/are in the acceptable range, the electronic control unit outputs an electrical signal to illuminate the green LED at step 74. Alternatively, and if the signal is not within the acceptable range the electronic control unit outputs an electrical signal to illuminate the red LED at step 76, wherein the red LED is indicative of improper installation and the green LED is indicative of a proper installation. Thereafter, nodes 78 and 80 will query if a stop command should be issued, which may correspond to an expiration of a time period or the system being shut down manually.

Alternative methods for providing indication of the tension in the adjustable tether include but are not limited to an audible chimes, and buzzers for providing an indication of an improper installation, or audible text or a visual display with indicia. A non-limiting example of a visual display is a liquid crystal display (LCD).

Accordingly, exemplary embodiments of the present invention provide a child seat with an electronic control unit that determines the tension of the adjustable tether and illuminates an indicator light, which is located on the child seat in a location that would be easily viewed by the operator and/or occupants of the vehicle, wherein the indicator light provides a means for determining whether the adjustable tether is properly installed. For example, one such location of the indicator light is on the face of the control unit display. In addition, the microcontroller may also provide an audible tone or voice response, indicating whether the appropriate tension exists in the tether. In addition exemplary embodiments of the present invention are contemplated for use with various forward facing child seats, various booster seats as well as rear-facing infant seats including those with detectable carriers.

In addition, and in accordance with alternative exemplary embodiments the electronic control unit can also be configured to provide indications of other conditions relating to the child seat and/or its installation. In this embodiment, the child seat will comprise an electronic control unit secured to the child seat, the electronic control unit being operably coupled to the tension sensor to receive the tension signal and the electronic control unit is also operably coupled to a plurality of sensors 90 each providing additional signals indicative of states of the child seat to the electronic control unit and the electronic control unit is capable of processing the additional signals to compare the additional signals to acceptable values, wherein the electronic control unit provides additional outputs indicating whether the additional signals are at acceptable values and the additional outputs are provided to additional LEDs disposed on the display. Of course, other methods of display are also contemplated for use in this embodiment.

Examples of such additional such parameters being monitored by the additional sensors include but are not limited to: monitoring infant seat harness latch state; monitoring infant seat harness tension; perform infant seat weight classification; monitoring infant seat-to-base interlock state; monitoring infant seat angle and seat orientation; monitoring infant seat for exposure to severe impact or vehicle crash; monitoring rear facing infant seat base for contact with vehicle seatbelt; monitoring rear facing infant seat base for tension of vehicle seatbelt or lower tether; monitoring chest retainer clip for proper engagement; monitoring chest retainer clip for proper vertical height on the harness; monitoring shoulder harness slots for proper adjustment wherein audible and/or visual indications or warnings are provided to alert an individual if there is non-compliance with any of the monitored states.

In each instance, the sensors are electrically coupled to the electronic control module wherein the electronic control module provides an electrical signal indicative of the property being sensed. The electronic control module will determine, using a look-up table or analog circuit monitors and suitable algorithms, a desired value for the sensed property, which desired value may be based upon the tension of the tether as determined by the tension sensor and if necessary, the control module provides an alert signal. In accordance with an exemplary embodiment a simple analog switch can be monitored with a simple comparator op-amp circuit, or logic gate wherein a signal may be generated for illuminating the display or providing another form of output (e.g., audible chime or visual text message). For the display shown herein and in accordance with an exemplary embodiment, the alert signal illuminates a green light when the sensed property is within a desired range, and a red light is illuminated when the sensed property is not within the desired range.

While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.