Control system for hydraulic tractor attachments and the like

• US 3,334,488 A
• Filed: 10/21/1965
• Issued: 08/08/1967
• Est. Priority Date: 10/21/1965
• Status: Expired due to Term

• Current Assignee: Lauck, John A.
• Original Assignee: Lauck, John A.
• Inventors: Lauck, John A.
• Application Number:
  US04/499,689
• Time in Patent Office: 656 Days
• US Class Current: 60/399
• CPC Class Codes: B60K 28/04 responsive to presence or absence of the driver, e.g. to weight or lack thereof
• CPC Class Codes: F15B 11/16 with two or more servomotors
• CPC Class Codes: F15B 2211/20576 with multiple pumps
• CPC Class Codes: F15B 2211/3116 the pump port being open in the centre position, e.g. so-called open centre
• CPC Class Codes: F15B 2211/324 manually, e.g. by using a lever or pedal
• CPC Class Codes: F15B 2211/50518 using pressure relief valves
• CPC Class Codes: F15B 2211/521 mechanically
• CPC Class Codes: F15B 2211/7058 Rotary output members
• CPC Class Codes: F15B 2211/71 Multiple output members, e.g. multiple hydraulic motors or cylinders
• CPC Class Codes: F15B 2211/781 one or more output members having priority
• CPC Class Codes: F15B 2211/85 Control during special operating conditions
• CPC Class Codes: F15B 2211/865 Prevention of failures

Claims

8. IN COMBINATION, A HYDROSTATIC TRANSMISSION, A MAKEUP PUMP, A HYDRAULIC MOTOR, AND A CONTROL SYSTEM FOR DIRECTING HIGH PRESSURE FLUID FROM SAID MAKE-UP PUMP TO SAID HYDRAULIC MOTOR AND SAID HYDROSTATIC TRANSMISSION, SAID CONTROL SYSTEM BEING DISPOSED BETWEEN SAID HYDROSTATIC TRANSMISSION AND SAID MAKE-UP PUMP WHEREBY THE FLUID FROM SAID MAKE-UP PUMP MUST FIRST PASS THROUGH SAID CONTROL SYSTEM BEFORE ENTERING SAID HYDROSTATIC TRANSMISSION, SAID CONTROL SYSTEM COMPRISING A VALVE MEANS OPERATIVE IN ONE POSITION TO PERMIT SUCH FLUID FROM SAID MAKE-UP PUMP TO BY-PASS SAID HYDRAULIC MOTOR AND FLOW DIRECTLY TO SAID HYDROSTATIC TRANSMISSION, AND OPERATIVE IN ANOTHER POSITION TO DIRECT SUCH FLUID THROUGH SAID HYDRAULIC MOTOR TO ACTUATE THE SAME AND DIRECT THE RETURN FLUID FROM SAID HYDRAULIC MOTOR TO SAID HYDROSTATIC TRANSMISSION.