4 1 



The then generally used prismatic movement was discarded in favour of 

 one by means of slides. The sliding piece itself is situated close behind the 

 coarse adjustment action, with which it is rigidly connected by screws. See Fig. 17. 



A worm-wheel, movable by means of an endless screw, is situated at the 

 lower end of the micrometer-screw and serves in a sense as a screw-head. See Fig. 17. 



Here also the force exercised by the micrometer-screw is transferred to the 

 movable body which carries the tube by a single contact between two hardened 

 steel surfaces. 



The whole mechanism, with the exception of the two milled-heads acting 

 upon the endless screw, is enclosed inside the crane-shaped carrier 

 and is thus protected against all direct damage from outside. An additional 

 safety appliance prevents injury to the micrometer-screw when the sliding piece 

 has reached the limits of its movement. 



29. 



Fig. 17. 

 lti:i;i.i:i:-s Micrometer Movement. 



(Full Size.) 



Qazt Sews, 3ct. 



