236 



OTHER AUTOGRAPHIC APPLIANCES. 



by the spring. Some of the later machines have been 

 made with a poise which is propelled by a screw and 

 operated either automatically or by hand, thus going back 

 to the less perfect system of taking the load indications 

 from the position of the poise. 



130. Other Autographic Appliances. Besides the devices 

 which have been described, there are many others in use. 

 The principles involved are the same in most cases, the actual 



INCHES 

 2:0 



1-5 



1-0 



0-5 



80 



60 



40 



20 



Loads In thousands of pounds. 



FIG. 113. Autographic Diagram, from Specimen of Machinery steel by 

 the Riehle Apparatus. 



differences being chiefly in matters of detail. The great 

 majority of autographic gears suffer from the defect which 

 has already been pointed out, namely, that the load move- 

 ment is made to depend on the position of the poise weight, 

 and is not controlled by independent means. The difficulties 

 of attempting to effect this are great, and, moreover, an 

 apparatus which is free from this defect must of necessity 

 be costly. 



Autographic gears have been applied to tests other 

 than those m simple tension or compression. In some 

 cases autographic records have been taken of cross-bending 

 tests, as well as those in torsion. Of the latter, two machines 



