Fast acting compressible stop

A mobile crane comprising:

• a carbody;
• ground engaging members elevating the carbody off of the ground;
• at least one support column mounted on a rotating bed;
• a compressible stop comprising:
• a housing having an internal cavity, a first housing end having a first interface interfacing with a first crane component, and a second housing end having a passageway into the internal cavity;
• a rod slidably mounted within the housing and passing through the passageway, a first rod end disposed within the internal cavity, and a second rod end located external to the internal cavity and having a second interface for interfacing with a second crane component;
• a floating piston dividing the internal cavity into a gas portion biasing the floating piston towards the second housing end, and a liquid portion;
• a valve assembly dividing the liquid portion into a support portion and a reserve portion, the valve assembly comprising a check valve allowing a liquid to flow from the reserve portion into the support portion, a pressure sensitive valve inhibiting the liquid from flowing from the support portion into the reserve portion when a liquid pressure is below a threshold pressure and allowing the liquid to flow from the support portion to the reserve portion when the liquid pressure is above the threshold pressure, and a frangible divider configured to rupture when the liquid pressure exceeds a rupture pressure.

A method of allowing a support column pivotally mounted to a crane component to rotate beyond a normal stop position in response to a sudden load change, the method comprising:

• providing a compressible stop comprising:
• a housing having an internal cavity, a first housing end having a first interface interfacing with a first crane component, and a second housing end having a passageway into the internal cavity;
• a rod slidably mounted within the housing and passing through the passageway, a first rod end disposed within the internal cavity, and a second rod end located external to the internal cavity and having a second interface for interfacing with a second crane component;
• a floating piston dividing the internal cavity into a gas portion biasing the floating piston towards the second housing end, and a liquid portion;
• a valve assembly dividing the liquid portion into a support portion and a reserve portion, the valve assembly comprising a check valve allowing a liquid to flow from the reserve portion into the support portion, a pressure sensitive valve inhibiting the liquid from flowing from the support portion into the reserve portion when a liquid pressure is below a threshold pressure and allowing the liquid to flow from the support portion to the reserve portion when the liquid pressure is above the threshold pressure, and a frangible divider configured to rupture when the liquid exceeds a rupture pressure;
• attaching one of the first interface and the second interface to one of the support column and the crane component;
• rotating the support column towards the crane component until the other of the first interface and the second interface contacts the other of the support column and the crane component;
• rotating the support column towards the crane component with the other of the first interface and the second interface in contact with the other of the support column and the crane component thereby compressing the compressible stop causing the pressure of the liquid in the support portion to reach the threshold pressure and to flow through the pressure sensitive valve into the reserve portion;
• and
• rotating the support column towards the crane component with the other of the first interface and the second interface in contact with the other of the support column and the crane component thereby compressing the compressible stop causing the pressure of the liquid in the support portion to exceed the rupture pressure rupturing the frangible divider.