PREVENTION AND REPAIR OF MECHANICAL INJURIES 149 



moval and replacement of blades in the one handle offers 

 special advantage where a large amount of pruning must 

 be done. It saves time going to and from the tool house 

 and investment in knives. Fig. 112 shows popular styles 

 of pruning knives. 



Pruning shears will be used a hundred times where the 

 tree pruncr is used once, and at least a score of times 



FIG. 108 POLE SHEAR PRUNERS, SLIDING HANDLE TYPE 



Nos. 1 and 2. Reverse or U-type. Not as handy in use as common hook type. 

 No. 3. Satisfactory light type. No. 4. Powerfully made and cuts fairly well, but 

 the head is extremely heavy. Undesirable. No. 5. Objectionable double guard 

 style. Pole seriously weakened by the peculiar lever device. No. 6. Double shear 

 type devised for light work. Pole weakened by peculiar lever device. 



to the knife. It is of especial use in pruning trees up to 

 the age of five or six years for the removal of branches 

 up to say half an inch in diameter. Many makes are 

 for sale, some of them excellent. Points to bear in mind 

 when choosing a pair are to have first-class steel in the 

 blade, because a keen edge is necessary to do good work 

 and prevent injury to the parts to be left on the plant. 

 Next, the shears should be free working, with a good 

 spring to 6pen them promptly after making a cut. The 



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