Apparatus and method for preparing a hydraulic work machine for towing

Abstract

An apparatus and method for preparing a hydraulic work machine for towing in response to a dead engine condition. The apparatus includes a source of hydraulic fluid, a standby pump system hydraulically connected to the source, a plurality of pilot controls adapted for electrical activation by the standby pump system, and a hydraulic brake system. The apparatus also includes a supply valve connected to the pilot controls, and at least one lift cylinder connected to the supply valve and adapted to lift an implement on the work machine. The hydraulic brake system and the lift cylinder are enabled for hydraulic control in response to activation of the standby pump system.

What is claimed is:  
     
       1. An apparatus for preparing a hydraulic work machine for towing in response to a dead engine condition, comprising: 
       a source of hydraulic fluid located on the work machine;  
       a standby pump system located on the work machine and hydraulically connected to the source;  
       a plurality of electrohydraulic pilot controls adapted for electrical activation by the standby pump system;  
       a hydraulic brake system located on the work machine;  
       a supply valve hydraulically connected to the pilot controls; and  
       at least one lift cylinder hydraulically connected to the supply valve and adapted to lift an implement on the work machine;  
       wherein the hydraulic brake system and the at least one lift cylinder are enabled for hydraulic control in response to activation of the standby pump system.  
     
     
       2. An apparatus, as set forth in claim  1 , wherein the standby pump system includes: 
       a hydraulic pump;  
       a motor electrically connected to the pump;  
       at least one battery electrically connected to the motor; and  
       a switch electrically connected to the motor and adapted to controllably activate the standby pump system.  
     
     
       3. An apparatus, as set forth in claim  1 , further including a sequence valve hydraulically connected to the standby pump system and adapted to controllably deliver hydraulic fluid to the hydraulic brake system. 
     
     
       4. An apparatus, as set forth in claim  3 , wherein the sequence valve is adapted to controllably deliver hydraulic fluid to the hydraulic brake system in response to the pressure of the hydraulic fluid from the standby pump system being at least a predetermined minimum value. 
     
     
       5. An apparatus, as set forth in claim  1 , further including a resolver valve adapted to provide hydraulic pressure to the pilot controls from one of a head end and a rod end of the at least one lift cylinder. 
     
     
       6. An apparatus, as set forth in claim  2 , wherein the switch is enabled in response to an operator holding the switch in an on position, and disabled in response to the operator releasing contact with the switch. 
     
     
       7. An apparatus, as set forth in claim  2 , further including a control panel located on the hydraulic work machine, the control panel including the switch and at least one hydraulic control lever. 
     
     
       8. An apparatus, as set forth in claim  7 , wherein one of the at least one hydraulic control lever is an implement lift control lever. 
     
     
       9. An apparatus, as set forth in claim  1 , further including a check valve located on the hydraulic output of the standby pump system to prevent hydraulic fluid from returning to the pump system. 
     
     
       10. An apparatus for lifting an implement on a hydraulic work machine in response to a dead engine condition, comprising: 
       a source of hydraulic fluid located on the work machine;  
       a standby pump system located on the work machine and hydraulically connected to the source;  
       a plurality of electrohydraulic pilot controls adapted for electrical activation by the standby pump system;  
       a supply valve hydraulically connected to the pilot controls; and  
       at least one lift cylinder hydraulically connected to the supply valve and adapted to lift an implement on the work machine;  
       wherein the at least one lift cylinder is enabled for hydraulic control in response to activation of the standby pump system.  
     
     
       11. An apparatus, as set forth in claim  10 , wherein the standby pump system includes: 
       a hydraulic pump;  
       a motor electrically connected to the pump;  
       at least one battery electrically connected to the motor; and  
       a switch electrically connected to the motor and adapted to controllably activate the standby pump system.  
     
     
       12. An apparatus, as set forth in claim  10 , further including a resolver valve adapted to provide hydraulic pressure to the pilot controls from one of a head end and a rod end of the at least one lift cylinder. 
     
     
       13. An apparatus, as set forth in claim  11 , wherein the switch is enabled in response to an operator holding the switch in an on position, and disabled in response to the operator releasing contact with the switch. 
     
     
       14. An apparatus, as set forth in claim  11 , further including a control panel located on the hydraulic work machine, the control panel including the switch and at least one hydraulic control lever. 
     
     
       15. An apparatus, as set forth in claim  14 , wherein one of the at least one hydraulic control lever is an implement lift control lever. 
     
     
       16. An apparatus for releasing a set of hydraulically actuated brakes on a hydraulic work machine in response to a dead engine condition, comprising: 
       a source of hydraulic fluid located on the work machine;  
       a standby pump system located on the work machine and hydraulically connected to the source;  
       a hydraulic brake system located on the work machine; and  
       a sequence valve hydraulically connected to the standby pump system and adapted to controllably deliver hydraulic fluid to the hydraulic brake system;  
       wherein the hydraulic brake system is enabled for hydraulic control in response to activation of the standby pump system.  
     
     
       17. An apparatus, as set forth in claim  16 , wherein the standby pump system includes: 
       a hydraulic pump;  
       a motor electrically connected to the pump;  
       at least one battery electrically connected to the motor; and  
       a switch electrically connected to the motor and adapted to controllably activate the standby pump system.  
     
     
       18. An apparatus, as set forth in claim  16 , wherein the sequence valve is adapted to controllably deliver hydraulic fluid to the hydraulic brake system in response to the pressure of the hydraulic fluid from the standby pump system being at least a predetermined minimum value. 
     
     
       19. An apparatus, as set forth in claim  17 , wherein the switch is enabled in response to an operator holding the switch in an on position, and disabled in response to the operator releasing contact with the switch. 
     
     
       20. A method for preparing a hydraulic work machine for towing in response to a dead engine condition, including the steps of: 
       depressing a switch to activate a standby pump system;  
       activating a motor in response to depressing the switch;  
       activating a hydraulic pump in response to activating the motor;  
       enabling a plurality of electrohydraulic pilot controls in response to depressing the switch;  
       controllably lifting an implement as a function of the switch being depressed and in response to engaging a hydraulic implement lift control lever; and  
       controllably releasing a set of brakes as a function of the switch being depressed and in response to engaging a brake release lever.  
     
     
       21. A method, as set forth in claim  20 , wherein controllably lifting an implement includes the steps of: 
       delivering hydraulic fluid to a head end of a hydraulic lift cylinder; and  
       releasing hydraulic fluid from a rod end of a hydraulic lift cylinder.  
     
     
       22. A method, as set forth in claim  20 , wherein controllably releasing a set of brakes includes the step of delivering hydraulic fluid to a hydraulic brake system.