100 



HANDBOOK OF MECHANICAL DESIGN 



RETAINING AND LOCKING DETENTS 



Knurled 



B A 



Fig. 69. — D riving 

 plunger, shown in en- 

 gagement at A, is pulled 

 out and given a 90-deg. 

 turn, pin X slipping into 

 the shallow groove as 

 shown at B, both members 

 being thus disengaged. 



Fig. 70.— The pin in the 

 collar attached to the 

 plunger rides on the end 

 of the handle when in the 

 disengaged position and 

 drops into the hole Y to 

 allow engagement. 



Fig. 71. — A long and a 

 S'hort slotted pin driven 

 into the casting give two 

 plunger positions. 



fngoped 

 posiljon 



Fig. 72. — The plunger is pinned to the knurled 

 handle, which is pulled out and twisted, the screw 

 A dropping into the locked position at X in the 

 bayonet slot. 



Fig. 73. — In this design, the 

 pin A engaging in the slot prevents 

 the plunger from turning. This 

 detent is used as a temporary 

 gear lock which is engaged for 

 loosening a drawback rod through 

 the gear. 



Fig. 75.— In 

 this design, the 

 plunger is re- 

 tained by stak- 

 ing or spinning 

 over the hole 

 at A. 



Fig. 74. — An adjustable gear-case 

 cover lock. If the door is pushed 

 shut, it is automatically latched, 

 whereas pulling out the knurled knob 

 A disengages the latch. 



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Fig. 76.— The end of the 

 plunger B bearing against 

 the hand lever A is concaved 

 and prevented from turning 

 by the dog-point setscrew 

 engaging the splined slot. 

 Friction is the only thing 

 that holds the adjustable 

 hand lever A in position. 



Fig. 77. — A spring-backed steel 

 ball makes an inexpensive but effi- 

 cient detent, the grooves in the rod 

 having a long, easy riding angle. 

 For economy, rejected or under- 

 sized balls can be purchased from 

 manufacturers. 



