detection of defect shock absorbers in swivel units

Safely detect shock absorber failure: The award-winning protection for your swivel units

What happens when a shock absorber fails unnoticed? In high-speed automation, this often leads to massive mechanical damage and expensive production downtime. Friedemann Wagner has developed a solution that is so innovative that it was awarded the Handling Award. Find out here how you can monitor the shock absorber status of the swivel unit via your PLC - with simple means.

The problem: The "creeping death" of the damper

Hydraulic shock absorbers are wear parts. When they lose their effectiveness, the swivel unit hits the end position unchecked. The consequence:

Rack and housing are damaged.
Attachments are affected.
Subsequent machining steps are disturbed or even damaged.
Production standstill.

Unplanned downtimes cause high costs

According to a study ("Value of Reliability" | July 2023 | Sapio Research), unplanned downtimes cost the German economy €147,000 per hour.
Curious? You can find more information in this link to the Industrial Production article!

The solution: Monitoring via PLC (Handling Award)

Our clever design, combined with monitoring, is based on a simple principle: bouncing. Our initiator senses the real stop position! An intact shock absorber brakes the movement in a controlled manner. A defective damper allows the piston to shoot into the end position unchecked and thus faster, leading to bouncing.
By querying the PLC for bouncing, the system immediately detects when damping decreases – even before mechanical damage occurs.

For the detection of shock absorber failure, we were awarded the "handling award for handling technology".

💡For technology geeks: the technical aspect for small workpieces

External stops reliably provide full holding force in the important end positions without play, because the drive torque corresponds to the holding torque.
Especially as a surface stop (1), they guarantee indispensably high accuracy in the long term. With the patented stop system (2), the entire rotation angle between 0° and 190° can be easily adjusted by screwing in or out. The stop screws are later counter-locked for fixation. At the same time, these stop screws serve to accommodate special initiators, which are screwed into the hollow screw via threaded bushes (3). These sensors can be set and aligned to within a few hundredths to confirm the stop situation exactly in the end position. A separate knurled nut fixes the axial position of the sensor. Since the initiator is nevertheless rotatably mounted, the cable outlet (e.g. for angled plugs) can be ideally adjusted.
Thanks to the exact end position query, combined with the fact that everything is constructively located on one side of the system (4), the control system can recognize the failure of the shock absorbers (5) as "bouncing" when the end position is confirmed. This allows the application, for example, to be stopped immediately before economic consequential damage occurs.

💡Expert Tip: Service life

The robust overall design separates the stop situation from the gearbox. The basis is formed by the fixed external stops, which are part of the milled housing made of high-strength aluminum. Fault loads caused by damper failure therefore do not immediately lead to the destruction of the entire system.

The following types are designed with the external stop as part of the housing:

Type SM
Type SE (sizes 4, 6+9)
Type SES (sizes 4, 6+9)
Why swivel drives from Wagner - more information can be found here in this overview.

The implementation: Step by step

To integrate the above monitoring into your control system, you only need the screw-in end position sensors NSS. This block diagram for step control provides a starting point, provided here as a PDF download.

Block diagram for shock absorber failure detection

Of course, we have also summarized this at the very beginning of the brochure of our swivel units.

Swivel Unit Brochure

Why this method is convincing

Cost-neutral: You do not need any additional hardware or attachments.
Preventive maintenance: You replace the damper exactly when it is necessary - not too early and not too late.
Award-winning technology: This logic was recognized as an outstanding innovation at the **Handling Award 2016**

Conclusion: Availability is a matter of design and logic

With Friedemann Wagner's shock absorber monitoring, you make your system a little "smarter". You use existing features to maximize the availability of your machine.

Well-thought-out rotary power packs from a manufacturer with more than 45 years of experience.