Lock-Offs and Their Look-Alikes

This article originated in the July/Aug 2018 issue of Safe Ride News.

It’s important for CPSTs to understand what is (and isn’t) a lock-off

Until 1996, CR installation with a lap-shoulder belt nearly always required using a locking clip to hold the belt tight. This was often difficult (or altogether overlooked), so it was a relief when other solutions came along.

One solution involved seat belt redesign. As required by the NHTSA “lockability” standard, seat belts of MY 1996 and newer vehicles must have a way to hold a CR tight without needing a locking clip (i.e., locking latchplates, switchable retractors). Later, the introduction of LATCH also provided a locking-clip-free alternative. But, before that, CR manufacturers began to offer another solution in the mid-1990s: the CR lock-off.

Initially, there was resistance from CPS advocates: How could a plastic CR component actually take the place of the familiar metal clip? Manufacturers explained that a lock-off and locking clip are equally effective as precrash belt holders, if used correctly; a lock-off holds the belt webbing to a set length by clamping it to the CR, while a locking clip accomplishes the same thing by pinching the belt webbing together at the latchplate.

Lock-offs rise in popularity

It soon became clear that it was typically easier to correctly use a lock-off than a locking clip. For several years, the few CRs that featured a lock-off (or lock-offs) were much easier to use in the many pre-1996 (pre-lockability requirement) vehicles that were used by families.

Naturally, the number of pre-MY 96 cars in use has declined steadily, and so today there are far fewer lap-shoulder belts that require the use of a locking clip (those having free-sliding latchplates and emergency locking retractors). Yet the number of CR models that feature a lock-off has grown. Although the lock-offs on today’s CRs are rarely needed to make up for lack of lockability in vehicle seat belts, manufacturers explain they have other purposes, as well. They often are intended to make it easier to get a tight CR installation and, sometimes, help prevent a taut, locked shoulder belt from tilting the CR to the side. Several RF-only bases and convertible/combination CR models have one of an array of lock-off styles, including one- and two-arm clamps, grooves, and, most recently, a variety of features that also tension the belt.

Look-alike devices exist on some CRs

However, in the past several years, another feature has emerged on some CR models: the lock-off “look-alike.” With a design similar to (or sometimes even the same as) a lock-off, these look-alikes are not true belt lock-offs at all. Rather, manufacturers explain their purpose as being to help with installation and/or to provide a seat belt guide. But careful reading of the owner’s manual reveals that they are not expected to hold the belt tight prior to a crash, so the vehicle’s locking mechanism (or, lacking that, a locking clip) must also be employed. Some of these are identified in instructions by names that include the term “lock-off” (while not being a true lock off), while others use alternative terminology (like belt guide or tensioning plate).

Distinguishing a lock-off from a look-alike

The coexistence of lock-offs and their look-alikes on CRs in the field can be confusing to some caregivers, but is especially vexing for CPSTs, who must understand how to safely use a wide variety of CRs. Wrongly assuming that a look-alike is a true lock-off is a serious misuse, as this could mean that the CR will not be installed as tightly as it should be at the moment of a crash.

So, how can a CPST tell the difference between a lock-off and a look-alike device? As stated, there is no way to know for sure simply by looking at it. So, as always, the only way to be sure is to carefully read the instructions. However, it helps to know the right way to read them, as follows:

First, find the section in the CR instructions that describes installation using a lap-shoulder belt, and read these instructions up to the point at which they tell how to use the device.

If the instructions state to switch the seat belt to locking mode once the device is employed, then the device is a look-alike. (The instructions will probably also state that a locking clip should be used if the belt cannot be switched; however, check the vehicle instructions to see if the belt has a locking latchplate. Although these are less often used to meet the vehicle lockability requirement, locking latchplates do exist in many vehicles and are a suitable means to hold the belt tight without needing a locking clip.)

If, on the other hand, the instructions do not indicate that any other steps are required for installation after the device is employed, the device is a lock-off.

In other words, instructions are unlikely to state outright whether a device is a true lock-off or not. CPSTs must understand the function of a true lock-off (eliminating the need for locking the belt using other means) and determine the device’s purpose based on the installation instructions. This lack of a clear statement on this point may be frustrating for CPSTs. However, manufacturers explain that CR owner’s manuals are written primarily for the CR owner; instructions, therefore, focus only on the way the CR should be used. Instructions that allude to other ways to install a CR that don’t apply to the model the manual is written for just add length to the manual and are likely to confuse a caregiver.

Faced with uncertainty about what is and isn’t a true lock-off, many CPSTs conclude that the safest thing to do is employ the device (whether a lock-off or look-alike), and then always switch the seat belt for every installation. While this “soft lock” (in which a belt is switched to locked mode but slack is not manually moved into the retractor) is allowed by many manufacturers (when asked), it is best not to assume that this is a good option without checking with the manufacturer.

Even manufacturers that do allow a soft lock usually say that it only complicates an installation and might cause the CR to tilt, if a taut shoulder belt begins to pull upward on one side. Some manufacturers don’t recommend this practice. For instance, Britax discourages the soft lock with ClickTight™ convertibles because, with that design, when the seat belt is unbuckled to remove the CR, the latchplate can be difficult to remove from the belt path because the webbing will not lengthen.

However, a benefit to employing a soft lock is that it prevents a child from becoming entangled in the seat belt. So, as always, read instructions carefully and contact the manufacturer if questions remain.