FARM MACHINERY 239 



slightly heavier, the steel beam is not so easily clogged with 

 trash. The shanks may also be of steel or wood, with the 

 same advantages. A break-pin device or a spring trip 

 should be provided to prevent breakage of the shank if a 

 root or stone be struck by the shovels. The best cultivator 

 shovels are made of soft-center steel hardened so as to 

 take a bright polish. 



The widths of the shovels vary from two to four inches, 

 and the wider shovels may be twisted so as to assist in throw- 

 ing the furrow to one side. The straight shovels are adjust- 

 able upon their shanks to accomplish the same results. 

 Where shallow cultivation is desired without a surface culti- 

 vator, the spring-tooth cultivator, with four to eight small 

 teeth mounted upon springs, is successfully used. 



The coupling of the beam to the frame is one of the most 

 important features of the cultivator, for it must enable the 

 beam to be shifted horizontally and vertically and at the 

 same time cause the 

 shovels to remain in a 

 vertical position. In 

 order that this part of 

 the cultivator shall ren- 

 der long service, due 

 provision must be 

 made for adjustment 

 for wear. 



The gangs should 



i i i j_i l Fig. 148. A riding cultivator with balance 



be SO Suspended that frame and hammock seat. 



they will swing in a 



horizontal plane and not be lifted from the ground when 

 swung to one side. Since there is a tendency to advance 

 the shovels as they are swung to either side, it is easy to see 

 why a long beam is more easily guided than a short one. 



