There are two types of misalignment: parallel and angular.

Parallel misalignment refers to pulleys that are outside the plane of other pulleys in the drive system, but whose shafts remain parallel with the other components.  Proper positioning of a pulley on a shaft will help ensure all pulleys are in a common plane.

Angular misalignment refers to pulleys which are within the drive system plane, but are tilted because their shafts are not parallel.

Both misalignment conditions can create belt tracking problems, excessive wear and belt stability problems.  Just a few degrees of misalignment can increase belt operating temperatures by 15°C, reducing belt life by as much as 50%.

Belt noise due to misalignment usually occurs in the shortest spans in the drive, and often arises between a backside pulley and an adjacent grooved accessory pulley.  Proper pulley alignment is especially critical in these situations.

Benefits of Belt and Pulley Alignment

  • Reduces premature belt wear
  • Cuts energy consumption
  • Decreases machine vibration
  • Leads to improved machine performance

The Clavis Pulley Alignment System uses a profile sensor using the laser triangulation principal for a two-dimensional profile detection. 

The laser module clamps onto a pulley and directs a laser line onto the edge of a second pulley.  The light is reflected by the second pulley into an image sensor which is a known distance and angle from the light source. 

The path of the light forms two sides of a triangle, the known distance between sensor and laser source forms the third side.  The position of the reflected light on the angled sensor corresponds to the distance of the object reflecting the light.

The sensor operates according to the principle of optical triangulation (light intersection method):

  • A laser line is projected onto the target surface via a linear optical system.
  • The diffusely reflected light from the laser line is replicated on a sensor array by a high-quality optical system and evaluated in two dimensions.

The laser line triangulation corresponds in principle to the triangulation of a laser point.  In addition, during the measurement a row of lines are simultaneously illuminated by the laser line.  Apart from the distance information (Z-axis), the exact position of each point on the laser line (X-axis) is also acquired and output by the system.

The image sensor is a fixed number of pixels (1280), however as the target object is moved further away from the sensor the width of the line increases.

At 66mm from the sensor, the projected beam is 25mm wide.

This gives an effective resolution of 25/1280 = 19.53125µm.


The trace points are checked to ensure their XY value lie within the acceptance region. Any points which lie outside of this region are highlighted in red to quickly indicate to the user where the problem lies.

The acceptance region is fully user definable, giving full control on final tolerance in both X and Y directions. Generally once a rough outline of the pulley is established, the acceptance region is drawn around the rough shape, while a single defining feature of the pulley is chosen ( i.e. an edge or V grove) and this is given a narrower (±0.5 typical) region of acceptance; this ensures the final position is tightly controlled.

Once the final position is set, both the trace and the acceptance region currently in use are stored for archival purposes.


The demand for companies to reach the best decisions based on real-time data insights have never been greater. The FourierBMS is designed to interact not only with operators and engineers, but also other systems and subsystems. PLCs play an important data gathering and reporting role in system transparency by serving and receiving data from plant quality systems.


Advanced process control and monitoring functions make it easy to view and collect data.


Fourier interfaces include:

  • PROFINET Networked Ethernet
  • RS232 Serial connection
  • 24v Isolated Outputs 

We have developed a range of FourierBMS controllers integrating PLCs produced by Siemens, Allen-Bradley, and Mitsubishi.

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