Conveyor control system for a self-loading scraper

Abstract

A control system for the hydraulically powered .Iadd.conveyor, such as an .Iaddend.auger, of a self-loading .[.auger.]. scraper that has a hydraulic cushion hitch which is locked out when the scraper is loading. A multi-position manually controlled pilot selector valve which is used to lock out the cushion hitch also initiates operation of the auger. The control system includes a pilot operated, normally open auger control valve through which flow of a signal line for a normally open unloading relief valve goes to drain. Moving the pilot selector valve from a first to a second position pressurizes the pilot line to close the auger control valve and thus isolate the signal line from drain, closing the unloading relief valve to isolate a pump for the auger motor from drain and cause it to power the motor.

What is claimed is: 
     
       1. In a self-loading auger scraper that includes a tractor, a scraper articulately connected to the tractor through a hydraulic cushion hitch assembly, a scraper bowl, an auger mounted in the bowl, a hydraulic motor for driving the auger, a fluid reservoir, first pump means for supplying fluid under pressure from said reservoir to the cushion hitch assembly, and second pump means for supplying fluid under pressure from the reservoir to the auger motor, control means for directing the output of said second pump means selectively to the auger motor or to the reservoir, said control means comprising, in combination: a manually controlled pilot selector valve which has at least first and second positions;   an unloading relief valve;   a pilot operated normally open auger control valve;   a pressure conduit connecting the output of the first pump means to the pilot selector valve;   a pilot line from said pilot selector valve to the auger control valve;   a drain line from the pilot selector valve to the reservoir;   a signal line from the unloading relief valve to the auger control valve;   a return line from the auger control valve to the reservoir;   unloading conduit means from the second pump means to the unloading relief valve;   drain conduit means from the unloading relief valve to the reservoir;   and drive conduit means from said second pump means to the auger motor,   a first position of said pilot selector valve connecting said pilot line to said drain line,   said auger control valve in said first position being open between said signal line and said return line to maintain the unloading relief valve open between the unloading conduit means and the drain conduit means,   and manual movement of said pilot selector valve to a second position serving to close the drain line and subject the pilot line to pressure from the pressure conduit so as to close the auger control valve between the signal line and the return line,   closing of said signal line serving to close the unloading relief valve between the unloading conduit means and the drain conduit means,   whereby fluid from the second pump means goes through the drive conduit means to the auger motor.   
     
     
       2. In a self-loading auger scraper that includes a tractor, a scraper articulately connected to the tractor through a hydraulic cushion hitch assembly, a scraper bowl, an auger mounted in the bowl, a hydraulic motor for driving the auger, a fluid reservoir, first pump means for supplying fluid under pressure from said reservoir to the cushion hitch assembly, and second pump means for supplying fluid under pressure from the reservoir to the auger motor, control means for directing the output of said second pump means selectively to the auger motor or to the reservoir, said control means comprising, in combination: a manually controlled pilot selector valve which has at least first and second positions;   a pilot operated, normally open auger control valve the pilot line of which is open to drain in a first position of said pilot selector valve;   an unloading relief valve having a signal line which connects to drain through said auger control valve, said unloading relief valve being normally open to connect said second pump means to drain;   and drive conduit means from said second pump means to the auger motor,   movement of said pilot selector valve to a second position isolating the pilot line from drain and connecting it to the first pump to close the auger control valve, thereby isolating said signal line from drain and closing said unloading relief valve, whereby in said second position of the pilot selector valve fluid from said second pump means goes through the drive conduit to the auger motor.   
     
     
       3. The combination of claim 2 in which the second pump means comprises two pumps, both of which are connected through the unloading relief valve to the reservoir in the first position of the pilot selector valve, and in which the output of the second of said two pumps passes through the unloading relief valve and joins the output from the first of said two pumps. .Iadd. 
     
     
       4.  In a self-loading scraper that includes a tractor, a scraper articulately connected to the tractor through a hydraulic cushion hitch assembly, a scraper bowl, a loading assist mounted in the bowl, a hydraulic motor for driving the loading assist, a fluid reservoir, a first pump means for supplying fluid under pressure from said reservoir to the cushion hitch assembly, and second pump means for supplying fluid under pressure from the reservoir to the hydraulic motor, control means for directing the output of said second pump means selectively to the hydraulic motor or to the reservoir, said control means comprising, in combination: a manually controlled pilot selector valve which has at least first and second positions;   an unloading relief valve;   a pilot operated normally open hydraulic motor control valve;   a pressure conduit connecting the output of the first pump means to the pilot selector valve;   a pilot line from said pilot selector valve to the hydraulic motor control valve;   a drain line from the pilot selector valve to the reservoir;   a signal line from the unloading relief valve to the hydraulic motor control valve;   a return line from the hydraulic motor control valve to the reservoir;   unloading conduit means from the second pump means to the unloading relief valve;   drain conduit means from the unloading relief valve to the reservoir;   and drive conduit means from said second pump means to the hydraulic motor,   a first position of said pilot selector valve connecting said pilot line to said drain line,   said hydraulic motor control valve in said first position being open between said signal line and said return line to maintain the unloading relief valve open between the unloading conduit means and the drain conduit means,   and manual movement of said pilot selector valve to a second position serving to close the drain line and subject the pilot line to pressure from the pressure conduit so as to close the hydraulic motor control valve between the signal line and the return line,   closing of said signal line serving to close the unloading relief valve between the unloading conduit means and the drain conduit means,   whereby fluid from the second pump means goes through the drive conduit means to the hydraulic motor. .Iaddend. .Iadd.   
     
     
       5.  In a self-loading scraper that includes a tractor, a scraper articulately connected to the tractor through a hydraulic cushion hitch assembly, a scraper bowl, a loading assist mounted in the bowl, a hydraulic motor for driving the loading assist, a fluid reservoir, first pump means for supplying fluid under pressure from said reservoir to the cushion hitch assembly, and second pump means for supplying fluid under pressure from the reservoir to the hydraulic motor, control means for directing the output of said second pump means selectively to the hydraulic motor or to the reservoir, said control means comprising, in combination: a manually controlled pilot selector valve which has at least first and second positions;   a pilot operated, normally open hydraulic motor control valve the pilot line of which is open to drain in a first position of said pilot selector valve;   an unloading relief valve having a signal line which connects to drain through said hydraulic motor control valve, said unloading relief valve being normally open to connect said second pump means to drain;   and drive conduit means from said second pump means to the hydraulic motor,   movement of said pilot selector valve to a second position isolating the pilot line from drain and connecting it to the first pump to close the hydraulic motor control valve, thereby isolating said signal line from drain and closing said unloading relief valve, whereby in said second position of the pilot selector valve fluid from said second pump means goes through the drive conduit to the hydraulic motor. .Iaddend.