Chairs and seats – Supplemental seat
Reexamination Certificate
1999-08-04
2002-01-15
Nelson, Jr., Milton (Department: 3624)
Chairs and seats
Supplemental seat
Reexamination Certificate
active
06338529
ABSTRACT:
FIELD OF INVENTION
The present invention relates to an add-on child restraint system for the protection of a child occupant placed in a motor vehicle and more particularly to a forward facing child car seat providing superior safety performance.
BACKGROUND OF INVENTION
Passenger restraint systems of motor vehicles provide adequate protection for adult passengers, but are inappropriately sized for small children. As a result, regulations have issued requiring the use of child restraint systems in motor vehicles. The regulations impose size, shape and mechanical performance requirements on child restraint system manufacturers to ensure that the restraint system is capable of safely securing the child in a variety of vehicle passenger seats during operation of the motor vehicle and, in particular, during periods of worst-case rapid vehicle deceleration events (e.g., hard braking or forward impact events). In recent years, more stringent requirements have been adopted for child restraint systems in response to continued incidents of injuries sustained by children due to faulty or inappropriately designed restraint systems. In particular, regulatory requirements in Canada, the United States, and the European Union governing the use of add-on child restraint systems (i.e., portable child car seats) in motor vehicles require that the restraint system must be capable of limiting passenger excursions during a simulated vehicle frontal impact event, as defined under the restraint system dynamic tests of the United States Federal Motor Vehicle Safety Standard No. 213 (FMVSS 213), the Canadian Motor Vehicle Safety Standard No. 213 (CMVSS 213) and the Uniform Provisions Concerning the Approval of Restraining Devices for Child Occupants of Power-Driven Vehicles (ECE R44.03, §8.1.3).
The impact test setup, procedure and test article performance requirements under FMVSS 213 and CMVSS 213 are defined in terms of the restraint system's intended use (i.e., forward or rearward facing restraint or a built-in restraint system) and the recommended passenger weight ranges (which is related to passenger size) since the adequacy of the restraint system during a forward impact varies depending on the passenger weight, size and position in the vehicle seat.
Forward Facing Add-on Restraint Systems
In the case of a forward facing add-on restraint system, test procedures distinguish between two categories of restraint systems: forward facing child restraints with harness and belt positioning booster seats. In the case of forward facing child restraints with harness, the car seat body includes a child restraint harness and a vehicle seat belt retention device (or seat belt pathway) for restraining the seat in the vehicle seat. In the case of belt positioning booster seats, the vehicle manufacturer supplied seat belt assembly is used to restrain the child and booster seat in the vehicle seat.
FMVSS 213 and CMVSS 213 require that the restraint system with harness must be capable of being fully restrained (as verified by the forward impact test) in the vehicle seat by a Type I seat belt assembly (lap belt only), or by the combination of a Type I seat belt assembly and a top tether secured to a vehicle supplied anchorage which is often located in the vehicle seat assembly rear filler panel. The Type I seat belt assembly restraint requirement for forward facing child restraints with harness is intended to ensure that the restraint system will perform adequately whether the vehicle seat comes equipped with either a Type I or Type II (lap and shoulder belt) seat belt assembly.
Impact Test Setup, Procedure and Performance Requirements
Under FMVSS 213 and CMVSS 213, the testing platform comprises a vehicle seat assembly mounted on an impact trolley subjected to a change in velocity by impact with a frontal barrier or an equivalent rearward acceleration of the trolley simulating the acceleration experienced during a forward impact. The standard seat assembly for the impact test is reproduced as FIG.
1
A. The impact test setup, procedure and data gathering for forward facing add-on child restraints will now be briefly described. The restraint system with an anthropomorphic test dummy is secured in the vehicle seat using the seat belt assembly mandated for the test (i.e., Type I seat belt assembly) and subjected to the forward impact loads. In addition to verifying the strength of the restraint system, the impact test is used to gather data on the acceleration and displacement of the test dummy during the impact test. This procedure is repeated for a variety of test dummy weights and sizes, depending on the recommended weights for the child restraint. For example, conventional forward facing child restraints with harness are usually recommended for use with children weighing between 22 and 40 lb. For this type of restraint, an impact test is required for both a test dummy simulating 9 month old, 20 lb. child and 3 year old, 33 lb. child. For seats recommended for children weighing between 40 and 50 lb., the impact test is required for a test dummy simulating a 6 year old, 48 lb. child. Neither FMVSS 213 nor CMVSS 213 regulate child restraints for passenger weights over 50 lb.
The limits set forth in the regulations are defined in terms of a maximum allowable forward dynamic displacements and accelerations of the test dummy, as measured during the impact test. Maximum allowable accelerations of the test dummy are defined in terms of maximum measured accelerations of the head and upper thorax. Maximum allowable forward displacements (or excursions) of the test dummy are measured at the head and either knee joint portions of the test dummy and are measured with respect to a seatback pivot axis (
15
) of the standard seat assembly (
17
), as illustrated in FIG.
1
A. FMVSS 213 require that neither the head nor the knee joint of the test dummy can exhibit a forward excursion during test exceeding a maximum excursion distance (L), which represents the distance between seatback pivot axis (
15
) and an imaginary plane (
10
) disposed in front of standard seatback assemble (
10
). Currently, FMVSS 213 imposes a forward excursion limit (L) of the test dummy head and either knee joint to 813 mm and 915 mm, respectively. Under CMVSS 213, the forward excursion limit (
10
) for the head is 720 mm (excursions of the kneejoint are not regulated in Canada).
The forward facing child restraint excursion limits and seat belt assembly restraint requirements under FMVSS 213 and CMVSS 213 require child car seat manufacturers to design restraint systems that must be capable not only of sustaining forward impact loads imposed during the impact test, but must also be capable of preventing the passenger and seat from exceeding the maximum allowable forward excursion (L). At present, there are no known forward facing add-on child restraints with harness that meet the forward excursion limit requirements of FMVSS 213 or CMVSS 213 for passenger weights above 40 lb. Moreover, there are no known child restraints with harness available that meet the requirements under FMVSS 213 or CMVSS 213 for weights ranging between 22 and 40 lb. without the use of an additional restraining top tether.
The Loading Environment During a Forward Impact
The ability of a particular child restraint system to meet the excursion limits requirements depends not only on the strength and/or stiffness properties of the restraint system, but also on the nature of the load environment during a forward impact event. During a forward impact, the conventional forward facing child restraint with harness is subjected to both an applied lateral load through the vehicle seat belt assembly and a forward tipping moment. The forward tipping moment is influenced primarily by the vehicle seat belt/child seat shoulder harness force couple carried by the car seat body. Since the lap belt restraint force applied to the car seat is not co-linear with the inertia load applied to the shoulder harness restraint, there is a resulting forward tipping moment applied to the child car seat propor
Asbach Ronald
David Bapst M.
Jr. Milton Nelson
Mattel Inc.
Morgan & Lewis & Bockius, LLP
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