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

  • pe1 = 6.0 bar pe2 empty = 2.0 bar.

With curve pe1 = 6.0 bar, the intersection point with pe2 = 2.0 bar is formed, connect the intersection point with the actuating cylinder scale, giving 24.5 mm actuating cylinder travel

 

  • Suspension pressure loaded pe41, 42 = 5.0 bar, suspension pressure empty pe41, 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 pe2 empty:

  • Vent connections 1, 41, 42 to pe = 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 pe1 at Port 1, the desired outlet pressure pe2 empty is controlled at Port 2. Port 1 has to be vented to pe1 = 0 bar before the screw B is adjusted.

Turn to the left at B raises pe2

Turn to the right at B lowers pe2

Pneu LSV Internal with letters.PNG
  • Vent Port 1 to pe1 = 0 bar. Control suspension pressure to pe41, 42 empty in actuating cylinder.
  • Control brake pressure pe1 at Port 1, the outlet pressure pe2 empty must correspond to the previously set value. If the outlet pressure pe2 empty is greater; again tension the return spring in the actuating cylinder using screw F till, when controlling pe1, the desired outlet pressure pe2 empty is achieved ( do not tension too much ).
  • Vent Port 1 to pe1 = 0 bar, raise suspension pressure pe41, 42 empty by approx. 0.7 bar, control brake pressure pe1 at Port 1, the pressure controlled at Port 2 must now be very slightly greater than pe2 empty. 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 pe2 empty again as a check), tighten locknut E.
  • Replace rubber cap A and bellows D as well as protective cover G. Check outlet pressure pe2 loaded:
  • Control the suspension pressure in the actuator cylinder to pe41, 42 loaded, control the brake pressure pe1 at Port 1, the outlet pressure pe2 must correspond to the value on the LSV instruction plate, the brake calculation or the value given by the vehicle or axle manufacturer, usually pe1 = pe2.
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