Mobile hydraulic drive designers make use of changing the state of motor circuits from series to parallel when "on the run" so vehicles can have a wide power range of speed and torque i.e increased gearing options.

Doing the same with hydraulic cylinders operating in series and parallel is just as easy. The issues to look out for are:
1. Intensification
2. How to easily re-position the cylinders from either parallel to series configuration i.e 180 degrees out of phase or in-phase.
3. Cavitation 

Here is a simple solution and modification HADES made to a CLARK 18T Container forklift. The CLARK forklift carrier needed the fork tynes to have a side shift option as well as the normal extend and retract.

There are a few commercially available methods to weigh truck pay loads. Some use load cells which is possibly the most accurate but a close second is measuring the airbag pressure to calculate the load. Loads cells are expensive and the use of  airbag pressure still gets the job done. There are limitations with all weighing systems mostly the vehicle needs to be stationary, variations in temperature causes discrepancies for airbags in the read out and if the load is not uniformly distributed over the axles measuring only at one point will allow for further errors. 

We devised a simple cost effective system that allows anywhere from measuring one point (for liquids) to multipoints (for solids and multi axles) with temperature compensation. It has preset density values for selected products or a user defined density parameter. This airbag weighing system costs less than half to a third of the price compared to anything on the market. Admittedly its no frills but gets the job done!

The whole kit consists of a programmed smart controller, a IP65 fully protected Screen, a cable and transducer, simple to install or refit onto an existing truck.

Below is how a basic air bag system works: