Trailer Guide Schematics Software

Setting the pneumatic LSV

Installation

The LSV is not set up in the factory with any particular suspension or brake pressures so these must be set by the vehicle manufacturer to the necessary values (LSV instruction plate). The setting (diagram or LSV Pivot point calculator) is made in a mechanical part and a pneumatic part.

Mechanical part

Setting the pivot point X

1. Determine the actuating cylinder travel with the help of the diagram

Diagram pneu LSV.PNG
2. Calculate the intermediate value with the formula

Formula pneu LSV.PNG

3. Determine pivot position X for the balance arm from the pivot scale:

scale for pivot point.PNG

Example

  • P1 = 6.0 bar P2 unladen = 2.0 bar.

With curve P1 = 6.0 bar, the intersection point with P2 = 2.0 bar is formed, connect the intersection point with the actuating cylinder scale, giving 24.5 mm actuating cylinder travel

 

  • Suspension pressure unladen P41, 42 = 5.0 bar, suspension pressure unladen P41, 42 = 1.5 bar, gives 5.14 intermediate value
  • Vertically above the value of the calculated intermediate point, the pivot position X can be read off the pivot scale for the balance arm, giving 30 mm pivot point.

Alternative method by using our pivot point calculator

  • Set the pivot point X corresponding to the value determined:

 

 

Remove cover G, hold both of the nuts between the balance lever and the frame with the hexagonal spanner 14 mm, loosen the locknuts on the balance lever and fixed bearing with the hexagonal spanner 17 mm and set the pivot position to the calculated value X. First tighten the nuts on the fixed bearing, set up the balance arm (centrally between the return springs for the 90° - position to the long axis of the LSV; if necessary, remove any pre-tensioning in the return springs by turning the adjustment screw F to the left), tighten the nuts 17 mm on the balance lever with about 12-13 Nm torque.

Pneumatic part

Setting the outlet pressure P2 unladen:

  • Vent connections 1, 41, 42 to P = 0 bar.
  • Remove the rubber cap A.
  • Place the hexagonal key 5 mm into screw B, shift the slider C against the force of the spring and see whether the automatic return takes place. If it does not return: remove bellows D, loosen locknut E, pre-tension the springs using screw F till the slider C returns to the starting position.
  • Turn the screw B so that when controlling the inlet brake pressure P1 at Port 1, the desired outlet pressure P2 unladen is controlled at Port 2. Port 1 has to be vented to P1 = 0 bar before the screw B is adjusted.

Turn to the left at B raises P2

Turn to the right at B lowers P2

Pneu LSV Internal with letters.PNG
  • Vent Port 1 to P1 = 0 bar. Control suspension pressure to P41, 42 unladen in actuating cylinder.
  • Control brake pressure P1 at port 1, the outlet pressure P2 unladen must correspond to the previously set value. If the outlet pressure P2 unladen is greater; again tension the return spring in the actuating cylinder using screw F till, when controlling P1, the desired outlet pressure P2 unladen is achieved ( do not tension too much ).
  • Vent Port 1 to P1 = 0 bar, raise suspension pressure P41, 42 unladen by approx. 0.7 bar, control brake pressure P1 at Port 1, the pressure controlled at Port 2 must now be very slightly greater than P2 unladen. If a higher pressure is not achieved then the pretension of the return spring is too great. To correct this, loosen the adjustment screw F till the desired change in outlet pressure is obtained (do not lower the spring tension too much, examine P2 unladen again as a check), tighten locknut E.
  • Replace rubber cap A and bellows D as well as protective cover G. Check outlet pressure P2 unladen:
  • Control the suspension pressure in the actuator cylinder to P41, 42 unladen, control the brake pressure P1 at Port 1, the outlet pressure P2 must correspond to the value on the LSV instruction plate, the brake calculation or the value given by the vehicle or axle manufacturer, usually P1 = P2.
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