History of the CG-Lock

During the R&D activities described below, the main objective was to create a device for securing an automobile lap belt in a similar way to that used on a commercial aircraft.

Early Development

The very first device tried was the commercially-available “H-clip” (circled upper left on the attached photograph), used to secure seat belts for infant seats. It achieved the main objective. But it was hard to adjust, couldn’t be adjusted “on-the-fly”, required the seat belt to be unlatched to be adjusted, “bit” into the hip, and had many other drawbacks to use.

The remainder of Column “A” and all of Column “B” represent attempts (shown chronologically) to make an “easily adjustable” variant of the “H-clip”. Many of the designs were improvements, but were too weak (bent/failed), allowed belt slipping, caused abrasion of the webbing, had sharp points that penetrated the hip, and/or other failings.

Columns “C” and “D” show progressions of “slip-on” tongues that had compression (friction) clamps to retain the lap belt (slipped or jammed tight and couldn’t be loosened easily), Cam clams (worked but were sub-optimal for weight, grip, or ergonomics), and attachment methods (the progression towards rear clamping can be seen in the design evolution).

Columns “E” and “F” show the progression of the combination of successful characteristics developed in the previous columns. The cam action clamp method, the rear attachment clamp on the tongue, and attempts at weight and size reduction. Functionality was achieved to some degree with all these prototypes. About 5 of the prototype designated “1” were hand made and given to others for testing, comments and feedback. All the feedback, including the very positive results were incorporated in subsequent models.

The Final Evolution

The last Column (“G”) represents the “final” evolution and refinement to the prototypes prior to the professional engineers’ R&D leading to full functionality, marketability, and production. The prototype designated “2” was the first to achieve true success in most key parameters (easiest of attachment and use, adjusts “on-the-fly”, light, relatively simple yet robust, holds tight). These were again field tested. The last 2 items (designated “3”) in the last column represent minor changes from “2”. These were made by CNC and tested under static, dynamic, and consumer test conditions.

Prototype “3” worked, but was not without many flaws: too big, unaesthetic, unreliable spring tension, could not be disabled, high torque moment (making it possible to detach), belt wear, metal fatigue, high cost if manufactured, easy to jam due to dust and grit, sharp edges, and many other issues that made it clear there was a lot left to do. This is where the professionals started (Altair Engineering, Troy, MI, USA).

Please note that the photograph above shows only a small portion of the total developmental prototypes created. Additional detail can be provided upon request.