248 



HANDBOOK OF MECHANICAL DESIGN 

 AUTOMATIC STOPS 



Thread or 

 wire 



SpooU^ 



Spool^ 



Sh'rrup swivels on 

 i'iiis point so ffiaf ii 

 cannoi reengage 

 '^ cronl< 



Osciiiat/nq 

 shaft 



Angle of con- 

 tinuous oscillation 



Stationary' 

 Feelers" 



Thread-' 

 Fig. 524. — A mechanism used on the Barber- 

 Colman spooler. When the thread breaks, the 

 feelers are released and the spiral spring causes 

 the spindle with finger to rotate. The latter 

 throws the stirrup into the path of the oscil- 

 lating crank, which on its downward stroke 

 throws the spool into the position shown dotted, 

 the stirrup then being thrown out of the path 

 of the oscillating crank. 



' Tension spring 

 —Idler 

 -4 — Idler carrier 



Continuously 

 rotating , / 



eccen trie > ^^/ 



To clutch ~, 



Fig. 525. — Mechanism used with variations on tubular 

 braiding machines. When braiding, tension on the wire or 

 thread lifts the idler carrier which thereby releases the pawl 

 from the ratchet on spool flange and allows the spool to turn 

 and unwind. When the machine stops, the tension on wire is 

 decreased, allowing the idler carrier to fall so that the pawl can 

 engage the ratchet. If the wire breaks while the machine is 

 running, the unsupported idler carrier falls to the base of the 

 standard, and when the standard arrives at the station in the 

 raceway adjacent to the cam C, the lug h on idler carrier 

 strikes the cam C, rotating it far enough to disengage a clutch 

 on the driving shaft, thereby stopping the machine. 



Crankshaft 



Unsealed 

 packages,! 



'Eccentric arm oscillates 

 con tinuously about the 

 X fixed center 



Recip rocafing 

 bar, Siop^ 



WW//////M/////. 



Fixed 

 center 



~~ Floating center in 

 guide block that 

 rides in slot 



Thread 

 tension 



Fig. 526. — When the thread breaks, the stop drops and 

 intercepts reciprocating bar. On the next counterclockwise 

 oscillation of the eccentric arm, the bar B is raised. A feature 

 of this design is that it permits the arm B to move up or down 

 independently for a limited distance. 



Ratchet wheel 



Fig. 527. — Arrangement used on some 

 package-loading machines to stop the machine 

 if a package should pass the loading station 

 without receiving an insert. Pawl finger F has 

 a rocking motion obtained from crankshaft, 

 timed so that it enters the unsealed packages 

 and is stopped against the contents. If the box 

 is not filled, the finger enters a considerable 

 distance and the pawl end at the bottom 

 engages and holds a ratchet wheel on the driving 

 clutch, which disengages the machine driving 

 shaft. 



