Standard_Parts_Catalogue

Page 357 | 1.4 Adjusting, Positioning, Locking with and without Position Indication GN 700 Adjustable Knobs continued The anti-backlash mechanism which operates on the principle of a bidirectional freewheeling and antireversing basis allows the transfer of movement in both directions without backlash. The adjustable knob is not suitable for applications on machines or equipments which are exposed to vibrations. The bushing is connected by the parallel key / keyway to the revolving shaft. The location ring remains static and centrally positioned by the bushing and the two pinch rollers, fixed to the machine frame or housing by three screws. The rotating knob with the knurled barrel is carried by the bushing. The scale ring is firmly anchored to the bushing and the driven shaft by two countersunk screws. If the knob is repositioned, one of the follower pins – depending on the direction of rotation – pushes the pinch roller against the pressure spring into an idling position which releases the bushing and shaft to rotate freely. The second follower pin on the opposite side reduces the movement of its pinch roller and ensures at the same time a firm grip and forward movement of the bushing while the first pinch roller remains in an idling position. When „releasing“ the knob, the pressure spring will push the pinch roller back into the grip position, thus linking the bus- hing again with the static section. The scale ring is connected firmly with the bushing and any readjustment of the shaft can be accurately controlled. This infinitely adjustable knob cannot, however, be used in such cases where the shaft to be adjusted runs ahead of the adjustment. The anti-backlash mechanism in this knob cannot be used as a bearing for the driven shaft. Description Hints for installation A perfect functioning can only be guaranteed if the shaft of the machine is positioned at a perfect right angle to the contact surface of the static part.