• Excel Industrial Gears Private Limited

PIV Chains

Excel Industrial Gears began making PIV (positive infinitely variable) Chains with a tie-up with Stone Wallwork, UK, the original manufacturers of PIV drives, PIV chains, and other mechanical variators as part of mechanical power transmission products. All critical components were originally imported from UK, but the company gradually began indigenising the components and now manufactures practically all the PIV spare parts in-house including PIV servicing of practically all makes of variable speed drives of German, French, American, Czech origin. The PIV unit consists of two pairs of opposed curved conical discs, mounted one pair on the constant speed shaft of the unit and one on the variable speed shaft. These opposed discs are keyed to the shaft, which enable them to slide axially on the respective shafts. Power is transmitted from one shaft to the other by a patented PIV chain of special construction, which rests in the Vee formed between these opposed discs, and runs at a diameter depending on the axial distance separating the discs. The mechanism controlling the axial movement causes one pair of discs to approach each other as the other pair separates, so that the chain rises in one pair of wheels by the amount that it descends in the other. Operation: the heart of the PIV unit is the all metal slatted chain and the grooved wheel faces. The slats in the chain move laterally to engage the groove in the wheel faces. Therefore the chain cannot slip. The pitch diameter of both pairs of wheel faces is controlled to an infinite number of positions by the pivoting control levers and the control screw. Maximum speed setting: the input shaft wheel faces are close together, forming a large driving diameter. The output shaft wheel faces are automatically separated to form a small driven diameter. Minimum speed setting: the input shaft wheel faces are far apart, forming a small driving diameter. The output shaft wheel faces are automatically closed to form a large driven diameter.