General Information
The Hi-Low Detector is a device used for detecting and marking the points ona roadway surface that deviates from the desired level of grade. It is aprecision-made straightedge, for checking both concrete and blacktop slabs.Basically, the machine consists of an I-beam body 10 to 16 feet long withriding wheels at the ends and a detector wheel at the middle, so that themachine can be steered on the surface. The detector wheel, located at themiddle of the machine, detects any vertical deviation of the surface from astraight line between the supporting wheels at the ends of the machine. Thevertical deviations are shown by a movable pointer over a visible scale.Markings can be made on the surface using a special dye kept in a reservoirand release valve control mechanism. The timing and location of the markingcan be controlled through a cable at the operator’s handle. The Hi-LowDetector is shipped completely assembled except for attaching the operator’shandle, rear steering rod, and dye release cable.
Assembly
1. Attached the handle and steering rod to the I-beam body.
2. Run the loose end of the dye marker cable through the guidebracket so that 7/16" (11mm) of cable wire extends beyond thebracket.
3. After tightening the bracket, adjust the push collar on the end of thecable wire so that it clears the control valve lever by 1/32" (0.8mm).
4. With this setting, the push collar should fully open the control valvewhen the dye release lever on the handle is actuated.
5. Connect the rear steering rod to the front wheel assembly. This willenable the front wheels to turn about 20° to the right or left.

Components.
1. Front Wheel Lock: The front wheel can be locked in a straightforwarthe holding peg. With this rod in the down or locked position, the front wDetector is used for aligning forms.
2. Tire Scrapers: An adjustable tire scraper is mounted in front of each 1/32" (0.8mm). These scrapers prevent mud and dirt from accumulatininaccurate readings. After long periods of use, it may be necessary to reach wheel.
3. Aerosol-Spray Dye Marking System: Irregular surfaces are marked bsignals, the operator depresses a button on the steering handle that codye sprays onto the irregular surface from a replaceable aerosol can thseries of long, parallel dye streaks laid down by repeated passes on thcorrection. Use of the non-clogging aerosol can for dye discharge elimiwaste.
Accessories/Replacement Parts
H-2790B Bell/Buzzer indicator SYSTEM. Powered by a 6-volt battery
H-2790D Replacement aerosol dye. Cartoon of 12, 12 oz. (340g) spray
Adjusting & Checking Accuracy
1. Quickly check for accuracy by hooking the spring-loaded line undern
2. To set the indicator wheel exactly on the line, loosen the wing nut at right on the line. With the wheel in this position, the indicator needle shturn rod at “C” up or down until a zero reading is obtained. Then tightenrests on lower stop “D”.
3. The Hi-Low Detector can be quickly checked for accuracy without usfront and rear wheel guides. This raises the wheels off of the ground sounderneath.
Maintenance
With normal use and handling, this machine will perform accurately over long pfor accuracy.
Technical Specification
•Frame
:
Rectangular aluminum stock
•Stands
:
Front and rear; for storage, transport,
•Wheels
:
Ground concentric with inside diamet
:
neoprene tires and adjustable scrape
:
one front, one rear and one center ind
•Dye Material
:
Bright orange; 12 oz. (340g) aerosol c
:
mounts beside indicator wheel;
:
contains no fluorocarbons; non-clogg
•Handle
:
For steering; with button for dischargi
•Scale
:
Vertical; large pointer; mounted above
:
magnifies variations 16X
•Gradations
:
1 mm
•Certified Readings
:
Magnified; range from 0 to ¼" (6.4mm
•Weight
:
H-2790: Net 70 lbs. (32kg); Shipping.