Interpretation ID: nht80-2.23

DATE: 04/29/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Quester Juvenile Products Company

TITLE: FMVSS INTERPRETATION

TEXT:

April 29, 1980

NOA-30

J.P Koziatek, P.E. Director, Technical Services Questor Juvenile Products Company 771 N. Freedom Street Ravenna, Ohio 44266

Dear Mr. Koziatek:

This responds to your letter of January 25, 1980, requesting an interpretation of section S6.1.2.2.1(c) of Standards No. 213, Child Restraint Systems. Section S6.1.2.2.1(c) specifies that in the 20 mph test of forward facing child restraints with fixed or movable surfaces designed to restrain the child, the restraint system's belts are not to be attached "unless they are an integral part of the fixed or movable surface." You asked whether the crotch strap used in your Kantwet "One Step" Model-400 child restraint would be considered an integral part of the movable shield used on that device. After reviewing the diagrams and description contained in your letter, I conclude that the crotch strap is not an integral part of the movable surface and thus must not be connected during the 20 mph test.

Amended Standard 213 is intended to address, among other things, the problem of misuse of child restraints. The principal misuse involves the failure to attach buckles and latches. To ensure that children using child restraints are afforded protection notwithstanding such misuse, the standard specifies that the belts are to be attached to restraining shields during testing only if they are integral parts of the shields. Webster's New Collegiate Dictionary (1977) defines "integral" as meaning "formed as a unit with another part." Attachment of belts that are integral parts is permitted since they are intended to remain attached whether or not the restraint is in use and thus are not subject to the type of misuse described above.

The crotch strap used in the Kantwet "One Step" is not an integral part of the movable shield. The movable shield is a complete unit by itself. The crotch strap is a separate device that must be manually connected to the shield every time the unit is used. In contrast, the two upper torso restraints appear to be integral parts of the shield since they are designed to remain attached to an adjustment device and anchorage which are in turn permanently affixed to the shield. Nevertheless, we are concerned about the possibility that the upper torso restraint could be detached from the adjustment device. We urge that you and other manufacturers take the additional step of assuring that the belts permanently remain integral parts of the adjustment device.

If you have any further questions, please let me know.

Sincerely,

Original Signed By

Frank Berndt Chief Counsel

January 15, 1980

Mr. Frank Berndt Chief Counsel NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION Nassif Building, Room 5219 400 Seventh Street, S.W. Washington, D.C. 20590

Dear Mr. Berndt:

Re: FMVSS 213-80 CHILD RESTRAINT SYSTEMS REQUEST FOR INTERPRETATION KANTWET "ONE STEP" MODEL 400

This letter is written to provide NHTSA with the rationale leading to the design and development of the new Questor Juvenile Furniture Company (QJFC) child restraint system (Kantwet "One Step" Model 400) and to request NHTSA's confirmation of the manner in which this particular child restraint system is to be tested to determine its compliance with FMVSS 213-80, as published in the Federal Register on Thursday, December 13, 1979. Most important, we have set forth information substantiating the fact that the crotch strap incorporated in our new combined harness/restraint is "an integral part of the fixed or movable surface" under paragraph S6.1.2.3.1 (c) of FMVSS 213, thereby permitting the fastening of this integral strap during test configuration II.

Much has been written about the lack of use of child restraint systems, their cost, and their incorrect or incomplete installation/use. These concerns are well documented and have been expressed by the general public, concerned groups interested in promoting improved child passenger safety, and NHTSA. NHTSA has obviously deliberated long and with great effort in an attempt to develop rulemaking that would address those aspects of child restraint system design and usage that increase child passenger protection when properly designed child restraint systems are correctly installed in passenger vehicles. FMVSS 213-80, as published in the Federal Register on December 13, 1979, also attempts to protect the child passenger by requiring child restraint systems to meet certain minimum performance standards when they are improperly or incompletely installed in a passenger vehicle. While it is impossible to predict all potential incomplete or incorrect installations of child restraint systems in passenger vehicles, it has become apparent that certain omissions in child restraint system installations occur at a relatively high rate.

Tests have shown that child restraint systems installed with a top tether strap do reduce the occupant's relative head excursion, however these systems are often installed by the consumer without the top tether strap. The convenience armrest incorporated in some systems is also frequently misused in that it is placed in its lowered position with its restraining strap fastened, but the harness straps which are always part of such a system and which provide restraint for the system's occupant are often left unfastened. FMVSS 213-80 has considered these two improper installations of restraint systems and requires minimum occupant protection when the systems are tested under these improper conditions.

Devices for seating children in passenger vehicles were available to the consumer long before the advent of NHTSA and safety regulations for automobile occupants. Prior to NHTSA rulemaking in 1971, the majority of such child seating devices provided no protection for their occupants in the event of even low-speed vehicle accidents. However, since 1971, and particularly since 1974, there has been significant improvement in the crashworthiness of products available for seating children in passenger vehicles. The improvement has been such that child seats for automobile can now be truly classified as child restraints or, as some have suggested, "child protectors."

QJFC and its predecessor companies have been in the business of manufacturing and marketig child seating devices and restraint systems for more than 25 years. QJFC, perhaps more so than anyone else, has recognized the tremendous improvement in occupant protection now available to the consumer with crash-tested child restraints.

Likewise, QJFC has seen considerable shrinkage of the annual sales of child estraiit systems as their crashworthiness has improved and their cost has increased, as compared with the child seating devices formerly manufactured. QJFC has been concerned throughout this transition period that the consumer is not always interested in safety when he has a choice to make or that he is not fully cognizant of the possible consequences when a crash-tested child restraint system is, first, not purchased and, second, not used properly when purchased.

Since 1972, QJFC has designed and introduced five child restraint systems to the marketplace. Each of these systems was designed to meet crash testing criteria. As the state of the art improved and as more meaningful testing criteria were learned or published, the individual restraint systems were re-designed or discontinued, to be succeeded by designs which improved crashworthiness. Concurrently with efforts to improve the crashworthiness of restraint systems, QJFC recognized the sensitivity of the marketplace to the cost and the ease of use of child restraint systems. This led to the design of the Kantwet "Care Seat," the first restraint system marketed which provided crash protection for the occupant from birth through 43 pounds. The system was designed to (and did) meet the maximum relative head excursion of 18 inches forward of the forwardmost point of the car seat back without the use of a top tether anchor strap.

To provide a crash-tested restraint system for children from birth to 17 pounds, at the lowest possible cost. QJFC designed and marketed the Infanseat "Dyn-O-Mite" child restraint. This product, with its attractive pricing and broad distribution, has been well-received by the consumer and has served to re-emphasize the sensitivity of the marketplace to price and ease of use.

These comments are offered to indicate the awareness that QJFC has of the marketability and proper installation of child restraint systems. In addition to our own design and market experiences, we agree with the objectives NHTSA has established to improve the performance of the restraints, increase the use, and minimize their misuse.

To this end, QJFC has taken the sum total of its 25 years of marketing experience and combined this with NHTSA's objectives to design its sixth new crashworthy child restraint system since 1972. This system, the Kantwet "One Step" car seat, Model 400, is of a design that is a significant departure from previously available child restraint systems, thus incorporating features not necessarily familiar to NHTSA or the general public. Certain aspects of the design of the "One Step" will require interpretation in order to test the restraint properly against FMVSS 213-80.

The features of the Kantwet "One Step" design can best be understood by referring to various drawings in conjunction with the description that follows. The drawings are enclosed with this letter.

The system consists of three main parts: the tubular steel frame, a padded molded plastic shell, and a harness/shield restraint. These are shown in Figure 1. Combining these three main parts allows the assembly to be used as a rear-facing system for infants and as an upright forward-facing system for children who weigh more than 17 pounds but less than 43 pounds, with this mode also capable of being used in a forward-facing reclined position. Thus, a single purchase enables the consumer to provide protection for his child from birth through 42 pounds in weight.

Dynamic testing has been conducted on prototype and production mode is of the "One Step," and the tests have indicated excellent compliance with the performance requirements of FMVSS 213-80 in all three installation positions. These dynamic tests have been conducted at a simulated impact of 30 mph, and the average maximum relative head excursion achieved without the use of a top tether strap has been less than 32 inches. Head injury criteria and average chest accelerations have been well within requirements on those occasions when instrumented test dummies were used.

These favorable test results are attributable to the combination of a harness and an impact shield restraint system where in the most desirable features of a five-point harness and an impact shield have been combined. The single greatest criticism by the consumer of an impact shield-type of restraint has always been the difficulty of keeping the occupant within the system. The freedom of movement available to the occupant of an impact shield restraint allows the occupant not only to climb out of the system but also, if he remains in it, to be out of the ideal position to absorb effectively the forces imposed during an accident. A five-point harness restraint system distributes crash forces satisfactorily to the occupant; however, the webbing of such a system, with continued use, becomes entangled and crossed over itself, and it begins to "rope" or twist upon itself. This roping and twisting of the webbing thus imposes higher localized loading to the occupant in a crash; also, in many cases, the consumer fails to utilize the five-point harness when placing a child in such a system because he does not wish to take the time to untangle and straighten the webbing first.

The "One Step" restraint system integrates the webbing of the upper torso restraint with the crotch strap and impact shield in a continuous connection. This arrangement provides some unique features and advantages not heretofore available with child restraint systems. These advantages are described below and shown in the appended drawings.

1. The security of a five-point harness system is provided, thus retaining the occupant, with the further guarantee that the occupant will be properly positioned in the system in the event of an accident.

2. A large padded surface is available with the impact shield located at the lower torso area, to distribute impact forces over as large an area as possible.

3. While the impact shield is designed to distribute impact forces to the lower torso area, it is also shaped in such a manner and positioned so that its lower surface rests against the occupant's upper thigh. This placement eliminates the need for a separate lap belt assembly for restraint of the lower torso. Thus, the possibility of a lap belt assembly's roping, twisting, and cutting into the pelvic area has been completely obviated. The intrusion of lap belts into the hip joint of test dummies has frequently been observed during crash testing in spite of the use of a crotch strap on a five-point harness restraint.

4. The impact shield, in addition to serving the aforementioned functions, also simulates the buckle of a five-point harness system in that it accepts the ends of the upper torso belts and provides a means of connecting the crotch strap to itself. Thus, the impact shield serves a multiplicity of purposes, as well as providing a means of "shielding" the occupant's torso and extremities against certain metal hardware items.

Reference to Figures 1 and 2 will highlight the similarities between a conventional five-point harness restraint system and integrated "One Step" combination harness/shield restraint system. The impact shield of the "One Step" essentially replaces both the retaining buckle and the lap belt of a typical five-point harness system, as shown in Figure 2. Both the impact shield and the buckle serve the same purpose of accumulating the belts and of fastening them together.

5. The belts of the upper torso restraint are routed from the back support surface of the system to and around the impact shield so that their "lie flat" position is guaranteed. Reference to Figures 1 and 3 clearly illustrates this. When the impact shield is raised or lowered for entrance or egress of the occupant, the shield maintains this "lie flat" condition of the upper torso belts, preventing any possibility of their roping, twisting, or becoming entangled with themselves or any other belting. Figure 4 shows the impact shield being raised, with the upper torso belts being lifted simultaneously from the occupant.

6. Since the upper torso belts and the crotch strap are sewed together to form a continuous loop about the restraint's occupant, adjustment of the upper torso belts automatically brings the crotch strap to its corrent length and the impact shield to its correct position for the size of the occupant. The restraint system can thus "grow" with the occupant or adjust to the amount of clothing worn by the child since the impact shield contacts its upper thighs.

7. Reference to Figure 3 shows the location of metal adjustment hardware on the underside of the impact shield. It can be seen that all hardware is away from the occupant and does not contact him. This feature eliminates the possibility of over-heated metal components burning the occupant on hot summer days, a situation that NHTSA has requested manufacturers to correct.

8. Further reference to Figure 3 shows the buckle which fastens the entire harness/shield restraint system together under the impact shield and therefore out of reach of the occupant. This feature prevents the child from purposely or inadvertently releasing the buckle and thus defeating the restraint. NHTSA has identified the release of buckles on five-point harness systems as being a significant problem and has tried to minimize the occurrence by requiring manufacturers to have a minimum release force for their buckles. The "One Step" restraint system has thus gone "one step" beyond NHTSA's requirements and eliminated accidental buckle release entirely.

9. Adjustment of the entire restraint system is accomplished simply by pulling on the ends of the upper torso restraint belts, as shown in Figure 3. As stated previously, this action adjusts the entire system to "fit" the occupant correctly and position him in the location and posture intended to absorb impact forces best. Further, once the adjustment is made, it cannot be loosened accidentally by the occupant, not only because the adjustment means is located out of reach but also because a separate and distinct secondary action is needed to pull the belts back from their adjusted length. To loosen the restraint's adjusted length of belting, it is necessary to lift one portion of the belt-adjusting mechanism, as shown in Figure 5, before the belting can be loosened.

Two important advantages result from this feature. First, the child cannot purposely or accidentally loosen the restraint through his movements or through playing with the strap slides that are the usual method of adjusting harness belting. Thus the child is always properly positioned to absorb impact forces during an accident. Second, the restraint system need not be adjusted each time it is occupied. Once the system has been adjusted to fit the child, the same "fit" will be available the next time the restraint is used since it will retain its length of webbing until the webbing length is purposely changed through the conscious actions shown in Figure 5.

10. Figure 6 is an enlarged view of the hardware as it is located under the impact shield. This view illustrates the routing of the upper torso belting through the adjustment hardware and also shows that the hardware itself is permanently fastened to the shield, thus preventing disengagement and possible loss of hardware from the system.

The combination of the above features makes the "One Step" child restraint the most convenient system to use. When the impact shield is raised, all belting is lifted clear of the seating surface, thus presenting an unobstructed area for the occupant. Once the child is seated, there is no need to search for belting or hardware under him. When the impact shield is lowered, the upper torso belts are brought into correct position over the child's shoulders and held in correct alignment to prevent their slipping from his shoulders since the belts are "fixed" in locations at either end of the upper torso portion of the belts. When not occupied, the belts are held in proper relationship to themselves and to the system itself, which precludes their roping, entanglement, and twisting. Once placed in a vehicle, the "One Step" can remain in the car, secured by the auto's lap belt, regardless of its position either forward-facing or rearward-facing, since the lap belt is routed under the restraint system's seating surface for all the restraint's positions. (Most other rearward-facing restraint systems are designed so that the vehicle belt used to retain the system in the vehicle passes over the occupant, which means the lap belt must be detached for the child's egress, with subsequent restraint usage requiring re-connection and adjustment of the vehicle belt.) Once the "One Step" is adjusted to "fit" the child, it need not be "re-fitted" each time it is used unless the child has increased in stature or wears bulky winter clothing since the adjustment mechanism retains the length of the adjusted belts until they are consciously altered.

**INSERT FIGURES**

QJFC believes the Kantwet "One Step" Model 400 child restraint system to be the most convenient crash-tested child restraint system available for use by children from birth through 42 pounds in weight. It is believed that this restraint incorporates the best knowledge and experience QJFC has gained in over 25 years of manufacturing and marketing juvenile products plus the knowledge NHTSA has provided to manufacturers of child restraint systems regarding the crashworthiness that such systems must provide.

It is QJFC's belief that when tested according to test configuration II, installation of the "One Step" system (as described in paragraph S6.1.2.3.1 (c) of FMVSS 213, published in the Federal Register of December 13, 1979) permits fastening of the integral crotch strap of the harness/shield restraint. NHTSA confirmation of this installation procedure for conducting test configuration II is requested.

I would be pleased to visit NHTSA personally to describe and discuss the "One Step" child restraint further, should that be desired.

Yours truly,

QUESTOR JUVENILE PRODUCTS COMPANY

J. P. Koziatek, P.E. Director, Technical Services

Attachments

JPK:MG

*Insert Figure 3, 4, 5, and 6 Here