Patent ID: 8353157
Filing Date: 2013-01-15
Classification: F04B,F15B

Abstract:
1. An open center hydraulic system comprising: a variable displacement pump having an inlet, an outlet and a sensing port, the pump configured to provide reduced fluid flow in response to a predetermined fluid pressure differential between the outlet and the sensing port; a first fluid circuit and a second fluid circuit in selective fluid communication with the pump; a first controlled pressure reduction device in fluid communication with the pump outlet and each of the first fluid circuit and the second fluid circuit; a flow regulating device in fluid communication with the sensing port in each of the first fluid circuit and the second fluid circuit; the first fluid circuit comprising: the second fluid circuit comprising: wherein the first controlled fluid pressure reduction device is configured to introduce a first induced fluid pressure reduction between the pump outlet and the first fluid circuit during operation of the first fluid circuit; wherein the first controlled pressure reduction device is configured to introduce a first induced fluid pressure reduction between the pump outlet and the second fluid circuit during operation of the second fluid circuit; wherein the fourth controlled pressure reduction device is configured to introduce a second induced fluid pressure reduction in the second fluid circuit during operation of the second fluid circuit; wherein during operation of the second fluid circuit, reduced fluid flow from the pump outlet is achieved as a result of the sum of the first induced fluid pressure reduction of the first controlled pressure reduction device and the second induced fluid pressure reduction of the fourth controlled pressure reduction device approaching the predetermined pump fluid pressure differential.