DEVIATION AND ITS CAUSES 11 



surveying boreholes and many of those appUed in core 

 orientation may be used for detecting initial curvature or 

 deviation. However, most of these are only suited to 

 separate application, very few of them being fitted for 

 employment during actual boring operations especially with 

 percussive boring systems. The difficulty has been well 

 solved by the device of Dr. Hermann Anschiitz-Kaempfe 

 of Kiel which provides an acoustic or audible warning 

 of the initial stages of deflection. He invented this 

 apparatus in 1915 and improved on it a few years later. 

 It applies particularly to percussive boring but may be 

 modified for rotary boring. It is essentially a means of 

 detecting deviation, measuring it, and later correcting it. 

 It has been applied successfully in both Europe and 

 America. The apparatus as applied in borehole surveys 

 is shown in Plate I, Figs. 1 to 5. 



Figure 1 (Plate I) is a vertical section of the boring 

 chisel bar and bit. Figures 2 and 3 are enlarged views of 

 this section at an angle of 90 deg. to each other, while Fig. 

 4 shows the electric drive circuit. The hollow bit holder a 

 holds the beveled bit ai below and the connection a2 above 

 to the rods, the dotted lines xx being the normal flushing 

 circuit. A closed outer casing tube as mounted in the hollow 

 bit holder a holds the transmitter and the inner casing tube 

 ai which is longitudinally adjustable in this by means of 

 buffer springs h and 6i and held by lugs c. An accumulator 

 battery with electric motor d in the transmitter drives a 

 worm di with its wheel d2 on support ds and thus the toothed 

 wheels d^. Four pins e about the worm wheel d2 engage 

 consecutively on rotation with the finger / of hammer /i 

 controlled by pressure spring g. Thus for each revolution 

 of wheel c^2 four blows of the hammer /i are produced at /a. 

 Toothed wheel d^ engages another toothed wheel h on shaft 

 hi and carries a screw thread barrel hi which can be dis- 

 connected by spring slides i, ii and i^. There is an electric 

 contact A' on slide i. 



The ball and socket end I of the barrel shaft hi allows it 

 to oscillate under the adjustable spring pressure pin m 



