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Fig. 106. Fifth Wheel:
1 – handle; 2, 4, 9 – springs; 3, 12 – nuts; 5 – locking cam; 6 – latch; 7 – cover; 8, 11, 20
– bolts; 10 – front catch; 13, 14 – brackets; 15 – cushion; 16 – saddle; 17 – pin; 18 – rear
catch; 19 – rotary support; 21 – rotary support; I – handle position before uncoupling
The release-and-coupling mechanism, which consists of rear catch 18, front
catch 10 and locking cam 5, which has two positions: opened and closed, is located
under the saddle. Spring 4, which holds the cam in its closed position, is set on the rod
of locking cam 5. Handle 1, which is fixed by nuts 3, is available on the rod end for
opening (moving) the cam. Nuts 3 serve to adjust the clearance between the catches
and the pintle of the semi-trailer. The cam in the opened position is held with the
help of springs 9 by latch 6.
Rear catch 18 rotates on pin 17 closed by cover 7 fastened by nut 12. Safety strip
19, which is fastened to the saddle by bolt 11, serves to prevent accidental opening of
the cam. Spring 4 presses the rod of locking cam 5 with the fixing fillet to the hole
wall.
Rotary support 21 is installed into the catch to avoid non-tight fitting of rear
catch 18 end to cam 5.
The design of the fifth wheel foresees adjusting the diameter of the hole for the
pintle to eliminate the clearances between the catch and the pintle.
