Specification
Types
- Type B: without rest position
- Type C: with rest position
- Pin hardened and grounded
Knob Plastic (Polyamide PA)
Information
Indexing plungers GN 817.3 realize a reasonable priced precision locating when guide bushings DIN 179 are used.
For this purpose a guide bushing DIN 179 is used as guide, whereby the dimension l3 of the plunger determines the length of the bushing.
The precise location is, therefore, not dependent on the guide pin in the plunger, but on the accuracy of the guide bush (bore tolerance F7) and the plunger (tolerance h7). Both components are hardened and ground. It goes without saying that the bush length also influences the accuracy of the positioning.
Type C is used for such applications where the plunger has to stay in its retracted position. To achieve this, the knob is rotated by 90° degrees after being retracted. A notch keeps the plunger in this position.
Construction and assembly instructions
Two different plunger pin lengths l1 are available for each indexing plunger diameter d1.
The length l3 must ensure that the indexing pin fully disengages, bushing length and plate thickness plus any gap can then be selected within certain margins.
For mounting bushings with tolerance n6, a hole with tolerance H7 corresponding to the external diameter is usually provided.
A selection of suitable guide bushings DIN 172 and DIN 179 is given.
