Torque Transfer Through Linkages/Arms

[Bisher Deirki]

Homework Statement

Find out the amount of force exerted by the screwjack/motor to lift the spill door upwards. The length of the different linkages is known as well as an estimate of the weight of the spill door.

Homework Equations

Torque = Force x Distance

The Attempt at a Solution

All I could think of doing is use the formula T= F*d; using the weight of the spill door as the Force required while the distance is simply the vertical distance between Linkage 1 and 4 - thus ignoring the horizontal linkages. Is this a good/correct approximation? Please let me know or point me towards a correct solution/theory to solve this. Assuming there is no resistance/friction between the different linkages.

 

[haruspex]

I'm having trouble understanding the diagram. The rod at the top is called a screwjack, which implies it rotates about its own long axis and has a thread along it. But it does not appear to engage a thread at the left hand end. It looks more like a simple rod (but then, rotating about what axis?).
The large disc at the bottom of the V looks like it might be a pivot on a fixed axis normal to the page. The other discs just axle joints, free to move around.
The 250N is described as the weight of the spill door, but it is shown as an upward force. I guess that is supposed to indicate the force exerted on the spill door to raise it.