Hydraulic control system for a swiveling construction machine

A swiveling construction vehicle comprising:

• an upperstructure including a primary implement assembly, the upperstructure configured to generate a variable pilot pressure signal;
• an undercarriage comprising:
• a pair of rotatable track assemblies, each track assembly rotated by a hydraulic travel motor that can be operated in a first speed and a second speed;
• a secondary implement assembly having a multi-function work implement controlled by the variable pilot pressure signal, a first function of the work implement is operable using a first hydraulic actuation device and a second function of the work implement is operable using a second hydraulic actuation device;
• a swivel coupling the upperstructure to the undercarriage, the swivel configured to allow the upperstructure to rotate relative to the undercarriage and to accommodate hydraulic lines and a line for the variable pilot pressure signal that extends between the upperstructure and the undercarriage;
• and
• a hydraulic diverter valve assembly housed in the undercarriage and configured to divert hydraulic power between the first hydraulic actuation device and the second hydraulic actuation device while simultaneously maintaining operation of each hydraulic travel motor so that each hydraulic travel motor is capable of shifting between the first and the second speeds, the hydraulic diverter valve assembly coupled to the pilot pressure signal and configured to divert the hydraulic power and shift each hydraulic travel motor based on a level of the variable pilot pressure signal.

A method of modifying an excavator that operates a single-function work implement on a undercarriage to operating a multi-function work implement on the undercarriage, the method comprising:

• providing an excavator comprising:
• an upperstructure;
• an undercarriage;
• a hydraulic swivel that rotatably couples the upperstructure to the undercarriage and houses hydraulic connections that extend between the upperstructure and the undercarriage;
• a pair of hydraulic travel motors;
• a multi-function work implement coupled to the undercarriage;
• a first hydraulic actuation device configured to operate a first function of the multi-function work implement;
• a second hydraulic actuation device configured to operate a second function of the multi-function work implement;
• installing a hydraulic diverter valve assembly in the undercarriage, the diverter valve assembly configured to divert hydraulic power between the first hydraulic actuation device and the second hydraulic actuation device while maintaining operation of each hydraulic travel motor in one of a first and a second speed, the hydraulic diverter valve assembly coupled to a variable pilot pressure signal from the upperstructure and configured to divert the hydraulic power based on a level of the variable pilot pressure signal;
• and
• changing controls in the upperstructure to coordinate with the diverter valve assembly.