78 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



sect ions of any thickness, from one micron to sixty microns, by turning the 

 knurled button at the buck of the case, just below the hinge, until the 

 number representing the desired thickness appears opposite the indicator 

 I (rig. 11) at the small opening in the side of the case near the balance- 

 wheel. The total excursion of the feed is ?>1 mm., allowing a sufficient 

 range for cutting a complete series of a very large object without the 

 necessity of a break in the series, due to resetting the knife and the f eed- 

 ing-mechanism. The pawl FP (rig. 11). which works into the teeth of 

 the feed ratchet-wheel F W (fig. 10) is located at the end of an arm F A 

 (fig. 11), which swings on an axis identical with that of the screw. 

 This arm is actuated by a connecting arm C A (fig. 11) running from 



F~IG.S 



XX\ CP CD 



Pig. 11. 



it to an excentric EC (fig. 11), which revolves with the balance-wheel 

 W. This excentric is so located on the axis that the feeding is done 

 when the object is at its upper limit and thus above the knife, thereby 

 avoiding the danger of forcing the face of the paraffin against the knife 

 on the upward stroke. 



By the side of the feeding ratchet-wheel there is another ratchet- 

 wheel M W (fig. 10) like it, but placed with the teeth running in the 

 opposite direction. Working into the teeth of this wheel is a pawl 

 MP (fig. 11) fastened to the upright support of the sliding bearing of 

 the feed block FB. This pawl is kept away from the teeth of its 

 rachet-wheel by a cam fastened to the arm carrying the feed pawl, and 

 is allowed to engage the teeth only for an instant at the extreme end of 

 the feeding stroke. This brings the wheels and feed screw to a definite 



