Good things have a habit of self-resurrection because the advantages that brought them to light the first time don’t stay buried. Changes in design, new concepts and materials, and, frequently, different circumstances or timing will provide better opportunities for successful application. As I see it, that is case for the Center-Pivot limb system that shapes the geometry for the new BowTech Guardian. If you have access to the May 1982 copy of Archery World (Bowhunting World’s predecessor) you can view a Bow Report that I wrote on the Total Shooting Systems Quadraflex, the first commercial version of a compound or conventional bow that employed a limb system that was pivoted at the center of the limb (patented by Joe Caldwell, of Tujunga Valley, California). Originally introduced with one-piece limbs that ultimately became split almost full length down the middle, and with wide (11/16-inch), transfer-type, round wheels, the Quadraflex delivered a Rating Velocity of 205.3 feet per second. The limbs were laminated with wooden cores, as solid fiberglass limbs were still in the stage of refinement at that point. Production of the bow lasted until about 1989 when it faded away for a combination of reasons.
The BowTech Guardian adopts the Center-Pivot limb system, but that is where the resemblance to the Quadraflex ends. The limbs pivot at their centers but are fixedly retained on a rigid part of the handle where the limb adjustment bolts are located. The mid-limb pivot is mounted on a movable extension of the handle, which is actually a pivoting link free to rotate on a pin supported by anti-friction bearings mounted on a short, solid, rearward extension from the upper riser. It should be apparent that the Guardian’s handle is substantially different from other bows, but that is limited to the risers’ ends. The handle’s center part is much the same as we are accustomed to seeing. From the lower limit of the grip section to just beyond the end of the sight window, it is quite conventional. Beyond those two points the handle is designed to accommodate the Center-Pivot limb system. The principal portion of the handle is fully machined from an aluminum alloy forging. The aluminum alloy pivoting links that extend outward to support the center pivots for the limbs provide for the slight longitudinal movement of the limbs as they flex when the bow is drawn or the draw weight is adjusted. Allowing for some movement at the limb pivot point is mandatory because the limbs’ inner ends are fixed by their attachment, which restricts all movement except rotation. *Read the rest of the report by downloading the PDF