106 



HANDBOOK OF MECHANICAL DESIGN 



Fig. 135. Fig. 136. 



Fig. 135. — Shouldered bushing 

 centered in counterbored hole. 



Fig. 136. — Bushing centered and 

 held by stud screw. 



Fig. 137. — Sheet-iron cover with 

 hinge ears fastened with shouldered 

 hex head stud or fillister head screws. 



Fig. 138.— 

 Poor design be- 

 cause screw 

 tends to turn. 



'11-- 



mm! -^ 



Fig. 139.— 

 The hinge stud 

 should screw in 

 tightly, and 

 head should 

 have ample 

 clearance. 



"^j^^T")* 



Fig. 140.— a 

 poor design where- 

 in all the thrust is 

 taken on the lower 

 case lug and the 

 span of the cover 

 lug is reduced. 



Fig. 141.— a 

 conventional ma- 

 chine door hinge. 



Fig. 142.— An 

 improved design 

 with lug drilled 

 and reamed from 

 opposite ends. 



Fig. 143.— 

 An incorrect 

 design because 

 it requires re- 

 moval of the 

 small pin for 

 disassembling. 



fW- 



\ . , \ ,e l 



Fig. 144.— 

 With a headless 

 hinge • pin, the 

 cover can be 

 lifted off. . 



Fig. 145. — Separable lugs are used 

 when the casting is too large for small 

 lugs to cast satisfactorily. 



Fig. 146.— Another 

 method of holding the 

 steel lug. 



Fig. 147. — Wrong method of 

 fastening steel lug, requiring cut 

 and try. End view shows 

 results. 



Fig. 148.— With in- 

 verted pin, the cover lug 

 can be smaller. Studs are 

 positioned before the final 

 pinning. 



