Roll bar manual operation function - GF91.59-P-2000R

MODEL 230 

Fig 1: Identifying Roll Bar Components For Manual Operation

Courtesy of MERCEDES-BENZ USA

Manual operation  (raising and lowering) of the roll bar takes place using the roll bar switch (N72s17)  in the lower control panel control module (N72)  . Manual operation is also possible with the Vario roof closed and while on the move.

The roll bar raising speed is considerably slower during manual operation than during crash deployment.

Raising the roll bar 

Pressure is applied to the roll bar hydraulic cylinder (2)  at the piston end when the roll bar is raised. During the upward movement of the roll bar the spring (5)  relaxes.

The oil damper (in the spring (5)) prevents non-cushioned impacts when the roll bar is raised.

The roll bar raising speed is controlled by a throttle in the operating element. The raising power comes from spring power and hydraulic power against the rod-end pressure and throttling power.

In order to prevent noise (locking pawl - gear rack) when the roll bar is being raised, the locking pawls are hydraulically lifted from the gear racks by the locking pawl cylinders (4).

Reaching the upper limit position is signaled by the top/bottom roll bar limit switch (S83/10)  .

Lowering the roll bar 

When the roll bar is lowered (automatic during Vario roof operation or using the roll bar switch (N72s17)  ) the locking pawl is released from the gear rack and the roll bar hydraulic cylinder (2)  , to which pressure is permanently applied at the rod end, is emptied at the piston end, which lowers the roll bar.

The downward movement causes the spring (5)  to be automatically pretensioned again for roll bar crash deployment.

Reaching the lower limit position is signaled by the top/bottom roll bar limit switch (S83/10)  .

Blocking manual operation 

Roll bar operation using the roll bar switch (N72s17)  is blocked by the RVC control module (N52)  in the following cases:

• during automatic roll bar deployment (crash deployment) 
• if a fault occurs at the roll bar switch (N72s17) 
• if the vehicle's onboard power supply has low voltage
• if the motor (A7/5m1)  of the RVC hydraulic unit (A7/5) overheats 
• when various faults occur in the RVC control module N52 

Manual operation after crash deployment 

In order to lower the roll bar after crash deployment, the roll bar switch (N72s17)  must be operated in the "raise" position until the catch (7)  is heard to engage. Pressure is applied to the roll bar hydraulic cylinder (2)  by the RVC valve block (Y55/1)  and moved upward to the deployment solenoid (Y57/1)  together with the catch (7) in order to "capture" the roll bar. The roll bar can then be lowered again.