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5.8 Bolster unit
The truck tractor has bolster unit designed for articulating the truck tractor with the semi-
trailer having hitching pivot of 50 mm diameter; for transferring tractive effort from the tractor to
the semitrailer; for providing the tractor semiautomatic hitch and unhitch with the semitrailer
Bolster unit consists of bolster 8, see Fig. 124, carriers 7 and the release-hitch mecha-
nism. Rubber cushions located in the joint of the bolster and the carriers ensure bolster rocking in
longitudinal and lateral planes and reduce dynamic loads.
5.8.1 Release-hatch mechanism is located under the bolster and shown in view «
А
»
(carriers 7 omitted for clarity). When pulling the unhitching control handle 1 the locking bar 10
releases locking hook 9 via lever 3; the hook turns to the position for hitching by spring 5 force.
When releasing the handle the locking bar 10 holds the locking hook 9 by spring 4 force.
At the hitching the semitrailer pivot turns the locking hook 9. The lock 10 and the handle
1 move to the closed position under the force of spring 4. Self-release safety lock 2 fixes handle 1
in that position.
1-unhitching control handle; 2-self-release
safety lock; 3-lever; 4-spring; 5-spring; 6-pipe;
7-carrier; 8-bolster; 9-locking hook; 10- lock-
ing bar
Figure 124 – Bolster Unit
