Trailer Construction; Chassis - PRONAR T900 Operator's Manual

SECTION 3 Pronar T900

3.2 TRAILER CONSTRUCTION

3.2.1 CHASSIS

Two versions of T900 trailer chassis are available: with triple axle mechanical suspension
(3.1), and with triple axle hydraulic suspension (3.2). The chassis consists of subassemblies
shown in figures (3.1) and (3.2). Lower frame (1) of the trailer is a structure welded from steel
sections. The main support elements of the frame are two longitudinal members connected
with crossbars. The brackets for mounting the suspension are welded to the lower frame.
In the chassis with mechanical suspension – figure (3.1) - the pressure applied by axles is
balanced by rocker arms located between leaf springs (6). The rocker arms are suspended
on brackets with maintenance-free rubber sleeves. Each axle has an adjustment bolt (5)
(bottle screw) on one end and a rigid string (7) on the other end. Adjustment bolts (5) are
used between all rocker arms. This solution makes it possible to set the same distance
between the axles on the right side and the left side of the trailer and position the wheels in
parallel to direction of travel. The chassis of a new trailer is set in the factory. Two external
axles (2) and (4) are steering axles while axle (3) is a rigid one.
The chassis with hydraulic suspension – figure (3.2) - consists of a lower frame (1), two
steering axles (2) and (4) and a rigid axle (3). Hydraulic cylinders (5) are shock absorbing
elements that connect the main frame with the axles. Parabolic arms (6) are the trailer
guiding elements. Each arm is connected with arm bracket (8) by means of a rotary pin.
The trailer axles are made from square bars terminated with a pin, where wheel hubs are
mounted on cone bearings. The wheels are single and equipped with shoe brakes activated
by mechanical cam expanders.
3.3