Safety Aspects & System Protection
Customers are often faced with challenges when it comes to the safe operation and reliable protection of their electromechanical drives. Insufficient system protection or improper planning can lead to unexpected failures, damage, or safety risks. Thorough knowledge and careful planning are therefore essential.
Here, you will learn how to safeguard your lifting system and ensure its long-term reliability.
How to solve these problems – with practical, application-oriented articles
I want to prevent safety gaps from causing costly failures or accidents
I don’t know exactly which safety measures are necessary for my application
How can I account for protection against environmental factors without limiting functionality?
I don’t know how to properly address safety requirements for people on lifting platforms
Why safety matters for electromechanical drives
Electromechanical drives, such as screw jacks or linear chains, must not only be powerful — they must be safe. Features like anti-rotation devices, self-locking mechanisms, and brakes prevent unintended movements and protect both people and machines.
Protection against environmental factors
System protection shields drive components from corrosion, wear, and other environmental influences. In demanding environments, this extends service life and ensures reliable operation.
Operating drives safely
This section focuses on exactly that. Learn which safety measures are truly necessary, how to effectively protect your drives from damage, and which solutions help minimize risks, keeping your systems safe, reliable, and long-lasting.
Let's dive in:
FAQs
Self-locking refers to the "non-slip" behavior of spindle-nut systems without external force. The degree of self-locking is influenced by the material pairing, the pitch angle, and the lubrication.
The manufacturer's rated load capacity shouldn't be exceeded. However, Screw Jacks typically have safety factors ranging from 1.5 to 2.5 times the rated load.
It prevents the rotation of the spindle. If a translational spindle were to rotate, linear motion would no longer be possible.
Anti-rotation is always necessary. Due to the sliding friction in the thread, the applied load would simply rotate along with it, and there would be no relative motion (linear motion).
The higher the axial force on the thread, the higher the frictional force, as Fr = FN * µ.
The confusion sometimes arises because in both cases, there's an additional element at the back of the spindle.
- The spindle travel limiter is merely a ring on the thread that prevents the spindle from falling out.
- The anti-rotation feature additionally prevents the spindle from twisting.
Both terms describe the ability of a spindle not to "slip" on its own when at a standstill.
Static self-locking refers to a thread angle between 2.4°-4.5°. In standstill, the spindle does not slip on its own, but it might not come to a stop on its own from motion. Dynamic self-locking occurs when there is an additional braking action from the dynamics. The thread angle is then smaller than 2.4°.
Self-Locking: Static vs. Dynamic | GROB Antriebstechnik GmbH chevron_rightCustomer side: The customer bears the load, preventing it from twisting. If the spindle is then attached to the load, it also cannot twist.
Gear side (product itself has a prevention rotation): We either use a groove running completely through the spindle with a corresponding key as a counterpart. Alternatively, a square block can be screwed onto the back of the spindle, and the protective tube is designed as a square tube.
In applications with high safety requirements, two independently acting holding mechanisms may be required. This could be dynamic self-locking + motor brake or, alternatively, an independently switchable dual brake on the three-phase motor.
Yes. Common voltage types are 24V DC / 230V AC / 400 VAC. Additional voltages in both direct and alternating current ranges are available upon request.
The safety margin can be increased or reduced. If reduced, it's important to ensure that block drive is always prevented during operation of the system.
Self-locking is achieved with a pitch angle below 4.5 degrees.
In standard operation, the SFM runs load-free with the main nut. If the main nut fails, the SFM takes over the load. A stroke can then be performed to shut down the system. Additionally, the SFM is also used as a reference nut for wear measurement.
No, you should provide a brake on the motor.
Increasing the ambient temperature does affect the duty cycle. A higher ambient temperature necessitates a longer cool-down period.
When transporting people, DIN EN ISO 17206 applies. This standard for event technology defines the required safety measures, safety devices, and system-relevant shutdowns.
The larger the screw diameter, the more complex an anti-rotation design using a keyway and key becomes. Rule of thumb: For screw diameters up to 40 mm, an anti-rotation system using a keyway and key is practical. For screw diameters of 55 mm and above, an anti-rotation solution using a square tube and square block is better.
