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.
The very first device tried was the commercially-available â€śH-clipâ€ť (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, couldnâ€™t be adjusted â€śon-the-flyâ€ť, required the seat belt to be unlatched to be adjusted, â€śbitâ€ť into the hip, and had many other drawbacks to use.
The remainder of Column â€śAâ€ť and all of Column â€śBâ€ť represent attempts (shown chronologically) to make an â€śeasily adjustableâ€ť variant of the â€śH-clipâ€ť. 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 â€śCâ€ť and â€śDâ€ť show progressions of â€śslip-onâ€ť tongues that had compression (friction) clamps to retain the lap belt (slipped or jammed tight and couldnâ€™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 â€śEâ€ť and â€śFâ€ť 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 â€ś1â€ť 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 (â€śGâ€ť) represents the â€śfinalâ€ť evolution and refinement to the prototypes prior to the professional engineersâ€™ R&D leading to full functionality, marketability, and production. The prototype designated â€ś2â€ť was the first to achieve true success in most key parameters (easiest of attachment and use, adjusts â€śon-the-flyâ€ť, light, relatively simple yet robust, holds tight). These were again field tested. The last 2 items (designated â€ś3â€ť) in the last column represent minor changes from â€ś2â€ť. These were made by CNC and tested under static, dynamic, and consumer test conditions.
Prototype â€ś3â€ť 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.