CHANGES IN THE EQUIPMENT INDUSTRY
THE USE OF CMI EQUIPMENT IS DESCRIBED IN MARKING GRADE, TRIMMING GRADE, SPREADING MATERIALS, STABILIZATION, CONCRETE AND ASPHALT PAVING. AUTOMATED GRADING EQUIPMENT (AUTOGRADE) CAN PLACE EACH DAY ALL OF THE ROCK, SOIL CEMENT, ASPHALT OR CONCRETE THAT CAN BE HAULED. THE MACHINE CAN GRADE 1/2 TO 2 MILES OF SUBGRADE PER DAY OR CAN FINE TRIM AS MUCH AS 6 TO 7 MILES PER DAY OF MATERIAL THAT IT HAD PREVIOUSLY SPREAD. THE SAME MACHINE WITH SLIGHT MODIFICATIONS CAN DO LIME, CEMENT, AND ASPHALT STABILIZATION. IT CAN DO AERATION AND MIXING OF SUBGRADE SOILS OR OF BASES. THE SAME MACHINE WITH A HEATED COMPACTING SCREED CAN DO BASE AND SUBBASE WORK AND CAN PLACE ASPHALT IN FULL WIDTH COURSES. WITH THE SLIPFORM MODIFICATION IT CAN DO FULL WIDTH PAVING, CAN PAVE WITH OR WITHOUT FORMS, CAN DO WIDENING AND HAS BEEN USED BY SEVERAL CONTRACTORS FOR SLIPFORMING RAMPS. AUTOMATED EQUIPMENT IS CAPABLE OF ACCURATE GRADE MAKING. THE CMI EQUIPMENT OPERATES USING SIX-SENSORS, ONE FOR THE FRONT TRACK STEERING, ONE FOR THE REAR TRACKS, ALLOWING THE NEGOTIATION OF SHORT RADIUS CURVATURES, FOUR SENSORS, ONE AT EACH CORNER, MAINTAIN GRADE TAKEN FROM STRINGLINE OR SKIS. THE SENSORS ARE ALIKE AND ARE DIRECT CURRENT TWO-CONTACT ROTARY SWITCHES WHICH ACTIVATE SOLENOID VALVES EQUIPPED WITH HYDRAULIC LOCKS TO PREVENT LEAKAGE. THE SOLENOID VALVES IN TURN CORRECT FOR GRADE OR ALIGNMENT BY ADJUSTING TWO WAY HYDRAULIC CYLINDERS. FLOW TO THE CYLINDER IS CONTROLLED BY METERING VALVES TO INCREASE OR DECREASE THE REACTION RATE. AUTOMATED EQUIPMENT MAY BE USED TO SPREAD UNIFORM COURSES OF MATERIALS SUCH AS PUGMILLED AGGREGATE OR SOIL CEMENT METERED AHEAD OF THE MACHINE BY WINDROW BOXES. IN THE WEST, HIGH SPEED PROJECTION OF BASE IS PERFORMED BY DUMPING AHEAD WITH BELLY-DUMP UNITS, SPREADING WITH AN AUTOGRADE, ALLOWING EXCESS MATERIAL TO FLOW OUT THE REAR MOLDBOARD CENTER WINDROWS WHERE IT IS RECLAIMED AND HAULED AHEAD. THE RECLAIMING OF THIS MATERIAL MAY BE DONE BY A BELT WHICH IS A NORMAL PRACTICE IN MISSOURI. MATERIALS MAY BE METERED INTO THE MACHINE BY THE USE OF A JERSEY TYPE OF THESE ATTACHMENTS AS POSSIBLE, ESPECIALLY THE HYDRAULIC PLACING HOT MIX ASPHALT BASES, BINDER, AND SURFACE COURSES. AUTOMATIC FOUR-CORNER GRADE CONTROL AND FRONT AND REAR STEERING ARE USED EFFECTIVELY IN SLIPFORM PAVING FOR SPREADING, PAVING AND FINISHING. MESH DEPRESSORS CAN BE AUTOMATED AND CROWN CHANGES THROUGH TRANSITION SECTIONS CAN BE DONE AUTOMATICALLY.
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Authors:
- Minor, W H
- Conference:
- Publication Date: 1969-4
Subject/Index Terms
- TRT Terms: Automation; Concrete finishing; Construction equipment; Deposits (Geology); Graders; Pavers; Paving; Screeds; Sensors; Slip form paving; Spreaders
- Old TRIS Terms: Windrows
- Subject Areas: Geotechnology; Highways; Vehicles and Equipment;
Filing Info
- Accession Number: 00219389
- Record Type: Publication
- Report/Paper Numbers: pp 143-149
- Files: TRIS
- Created Date: Jul 27 1970 12:00AM