SURFACE IRREGULARITY

Modified Roughness Indicating Machine (Merlin)

EKE 570:

Features:
•    Easy to Use
•    Self Calibrating
•    Robust
•    Easily Maintained
•    No Complex Calculations
•    Measures Displacement to less than a millimeters

The unevenness of road surface is an important measure of road condition and a key factor in determining vehicle operating costs. A number of instruments have, therefore, been developed for measuring unevenness, which is usually called roughness and standard roughness scales have been established. However, many of the instruments are expensive and complicated to use or require regular calibration. 
Modified Roughness Indicating machine is a simple machine to measure roughness, also called MERLIN - Machine for Evaluating Roughness using low-cost Instrumentation. 
The device can be used either for direct measurement or for calibrating other instruments such as the Vehicle Mounted Bump Integrator. The equipment is easy to use, self - calibrating, robust, easily maintained and employs readily available components.
Principle of Operation:

The machine consists of a motel frame 1.8 meters long with a wheel at the front and a metal foot at the rear, above the rear foot are handles used for moving the machine, Midway between the wheel and the foot is a probe which is attached to a weighted arm to hold it on the road surface.

At the other end of the arm is a pointer which moves over a prepared chart consisting of a series of 5 mm wide columns.

The arm is provided close to the probe so that a vertical displacement of the probe of 1 mm produce an equivalent displacement of the pointer by 1 cm of the pointer.

The position of the pointer on the chart hence gives an accurate indication of the position of the probe with respect to an imaginary lines, which joins the bottom of the wheel and rear foot.

If the position of the pointer is noted at a number of places along a road, then the rougher the road, the greater the spread of readings, it has been show that the spread correlates well with road roughness as measured on standard roughness scales.

Unevenness Indicator

EKE 571:

Consists of a mobile frame of metallic tubing, mounted on two datum wheels, respect to which the irregularities are determined . A probe wheel is mounted in the line of datum wheel. Movement of the probe wheel is taken to the pointer through a sprocket wheel. The pointer moves over a graduated dial. Handles are provided at either end of the frame for easy operation. As the instrument is moved along a line on the test surface, the probe wheel undulates with the undulations in the test surface leading to electric buzzing whenever the unevenness exceeds the set value.

Automatic spraying of color is done at locations where the  unevenness  is larger than the preset maximum value. The extent of bumps (protrusions and depressions) is instantaneously indicated by the pointer on the dial.

Profilograph

EKE 572:

Consists of a mobile frame supported on front and rear wheels three meters apart, with a pneumatic tyred probing wheel at which provide a line of reference with its centre. The probing wheel drives the recording mechanism which records the profile of the surface under test. Recording is done on the graph paper with 1 to 1 vertical scale and 1 to 200 horizontal scale. Arrangement for raising and locking the probing wheel, when the instrument is not use, is also provided.