Adjustment means for roll crushers with gas hydraulic springs

In a crusher of the roll type having a crushing roll mounted on and movable with respect to a crusher frame and a pair of gas hydraulic spring assemblies for maintaining the location of the roll with respect to the frame during crushing operation up to a predetermined crushing load, each spring assembly including at least one cylinder assembly comprising a cylinder closed at its opposite ends by first and second end walls, a floating piston slidably disposed in the cylinder and normally spaced from the first cylinder end wall, a compressible fluid pressurizing the space between the floating piston and the first cylinder end wall, a main piston slidably disposed between the floating piston and the second cylinder end wall and defining first and second chambers on the respective opposite ends of the main piston between the floating piston and the second cylinder end wall, a piston rod connected to the main piston having its outer end extending through and beyond the second cylinder end wall, the improvement comprising:

• means for adjusting the location of the movable roll relative to the frame by varying the overall length of each of the spring assemblies independently of the compressible fluid, said means in the case of each spring assembly including a non-compressible fluid normally filling each of the cylinder first and second chambers, and a hydraulic system for optionally and conjointly varying the volume of the non-compressible fluid in each of the two chambers effective to cause relative movement between the main piston and the cylinder and for optionally varying the volume of the non-compressible fluid in the first chamber only effective to vary the pressure of the compressible fluid between the floating piston and the first cylinder end wall, the first cylinder end wall being operatively secured to either the adjacent end of the movable roll or the frame and the outer end of the piston rod to the other thereof so that thrust upon the roll during crusher operation is transmitted to the compressible and non-compressible fluids, the non-compressible fluid and the pressure of the compressible fluid in the spring assemblies together being effective to maintain the location of the movable roll with respect to the frame up to said predetermined crushing load.