OR SUBSOILING PLANT, 



79 



TTL 



in which the cable is caught ; the levers 

 a and b are joined by the rings c and d to 

 the chain g. Under the effect of the 

 traction the cable is gripped at m. 



To displace the capstan A (Plate L), 

 in the direction of arrow 3, the cable g 

 must be slackened ; this is done some- 

 times by hand with a crowbar, or with Fif? 44 ._ A utomatic Gripper. 

 a special device (Fondeur and Pelous, 



Fig. 47), serving to 

 haul it back. In other 

 systems it is done by 

 horses (Fig. 45). To 

 displace the capstan in 

 yr^^^ 7 the direction of arrow 1 

 ^ /; ^^\^ a small chain a a 



passing over a pulley P 

 fixed on the chain n ri 

 is fastened to the pole 

 by a hook. When the 

 horses pull in the direc- 

 tion of arrow 2, the 

 chain g g' is slackened ; 

 the horses are backed, 

 the chain a unhooked 

 from the pole L, and the point of traction g shifted a dis- 

 tance equal to the width of the sod to be turned. 



To facilitate these different 

 operations, several implement 

 makers mount the capstan on four 

 rollers travelling on rails.* The 

 rails are made of iron rolled 

 joist girders, as used in struc- 

 tures (T Fig. 46), lying flat on 

 the previously levelled ground. 



The traction R exerted on the 

 rollers resting against one of the 

 flanges is equilibrated by the re- 

 sistance of this beam gripping in 

 the ground ; this is why it is pre- 

 ferable to sink the beam in the 



Fig. 45. Diagram showing how the Capstan is 

 Displaced. 





* In 1889 H. Beauquesne (Journal d' Agriculture Pratique, Vol. L, p. 460), 

 mentioned this device as having been applied before by Grue", Valessie, and 

 several others. 



6279. F 



