Clamping units – find manufacturers and suppliers

Clamping units are mechanical or electromechanical safety components that are used to safely stop, hold or secure linear movements in the event of danger.

In contrast to drive systems, clamping units do not generate movement, but are used to securely fix shafts, rods, rails or guides. They therefore perform an important function in the area of machine safety and contribute significantly to the protection of people, machines and workpieces.

The functionality of clamping units, their most important types, typical areas of application and their advantages are explained below.

How clamping units work:

Clamping units work according to the principle of force-fit or form-fit locking.
They engage directly with a guide element such as a linear guide, a piston rod, a shaft or a rail and generate a holding force that prevents movement.

In many applications, clamping units work according to the so-called fail-safe principle.
The clamping force is generated by springs and only released by an external energy source - for example compressed air, hydraulics or electrical energy. If the energy supply fails, the clamping is activated automatically.

The basic sequence includes

1. Release of the movement by releasing the clamping.
2. Normal movement of the axis or machine.
3. Activation of the clamping in the event of standstill or danger.
4. Safe stopping or braking of the movement.

Depending on the design, clamping units can:

1. Hold positions.
2. Perform emergency braking.
3. Secure vertical loads.
4. Reduce overtravel movements.
5. Secure maintenance positions.

Modern systems achieve very high holding forces with a compact design and short reaction times.

Types of clamping units:

1. Spring-operated safety clamping units:
   This design is particularly widespread. The clamping force is generated by integrated springs.
   Features: Energy-independent holding force, automatic activation in the event of power failure and high operational reliability.
   Suitable for safety applications. They are often used on vertical axes where the load must be prevented from dropping.
2. Pneumatic clamping units:
   These are actuated by compressed air.
   Features: Fast switching times, simple integration, low operating costs and high repeat accuracy.
   They are often used in automation systems and handling systems.
3. Hydraulic clamping units:
   Hydraulically actuated systems generate particularly high clamping forces.
   Features: Very high holding forces, suitable for heavy loads, compact design and high rigidity.
   Typical areas of use are machine tools and heavy-duty applications.
4. Electric clamping units:
   Actuation is via electromagnetic or motorized systems.
   Features: Simple electrical integration, good controllability and no compressed air supply is required.
   Suitable for modern automation concepts.
5. Brake clamping units:
   These systems are specially designed to brake moving masses in a controlled manner.
   Features: High braking forces, short reaction times and protection against overrunning movements.
   They offer increased machine safety.
6. Holding clamp units
   They are used exclusively to hold a position securely and not to brake moving loads.
   Properties: High static holding forces, low wear and a long service life.
7. Rail clamps:
   These clamping units engage directly with linear guides or guide rails.
   Features: High positioning accuracy, direct force transmission.
   They allow compact integration.
8. Shaft clamps
   They are used on round shafts or guide rods.
   Features: Simple installation, cost-effective solution.
   These clamping units offer a good holding effect.

Use of clamping units:

1. Machine tools:
Clamping units secure axes against unintentional movements and increase positioning accuracy during machining.

2. Automation technology:
In handling and assembly systems, they are used to position and secure moving components.

3. Vertical axis systems:
Here they prevent loads from dropping in the event of a power failure or emergency stop situations.

4. Robotics:
Clamping units secure robot axes and increase safety during maintenance work.

5. Lifting and conveyor technology:
They prevent the unintentional movement of loads and provide additional operational safety.

6. Medical technology:
In medical devices, they secure moving assemblies and patient positioning.

7. Test and measurement technology:
Clamping units ensure precise fixation during measuring and testing processes.

8. Stage and event technology:
They secure movable constructions, lifting systems and load supports.

Advantages of clamping units:

• High level of safety: the biggest advantage lies in the reliable protection of people and systems. Fail-safe systems in particular significantly increase operational safety.
• Protection in the event of power failure: Many clamping units remain effective even without power, compressed air or hydraulics and prevent dangerous movements.
• High holding forces: Even compact designs can absorb very high forces.
• Fast response times: Clamping units react within milliseconds and are therefore suitable for safety-critical applications.
• Increased positioning accuracy: Position deviations are minimized thanks to backlash-free fixing.
• Low wear: Many systems are virtually wear-free and have long maintenance intervals.
• Compact design: Modern clamping units can be integrated into existing machines to save space.
• Simple retrofitting: In many cases, they can be installed in existing systems without major design changes.
• Support for safety standards: Clamping units help to implement safety requirements and machine guidelines.

Clamping units are important safety devices for machines, systems and automated systems. They enable movements to be held, fixed or braked safely and protect both people and technical equipment from the consequences of uncontrolled movements. Clamping units are therefore an indispensable component of modern safety and automation technology.

Below is an overview of the most important points that should be considered when purchasing clamping units:

Clamping units perform a central protective function in modern machines and systems. They prevent uncontrolled movements of axes, slides, loads or tools and make a significant contribution to the safety of operating personnel, machines and production processes. They are particularly indispensable in vertical axes, robot systems, machine tools, handling systems and automated production lines. An incorrectly selected clamping unit can impair machine safety, lead to unplanned downtimes or fail to meet the requirements of safety standards.

• At the beginning of the procurement process, it must be clearly defined which safety task the clamping unit should fulfill.
• The requirements for a holding clamp differ considerably from those of a safety brake clamp. A precise definition of the intended use therefore forms the basis of every procurement decision.
• A key selection criterion is the actual load on the clamping unit.
• Additional safety factors must be taken into account, particularly in the case of vertical axes, as falling loads can cause personal injury and damage to property.
• A professional design is always based on the maximum loads that occur and not on the average operating values.
• Clamping units are developed for different guide systems. The geometry of the guide directly influences the achievable holding force and functional safety.
• So-called fail-safe systems have become established for safety-relevant applications. Here, the clamping force is generated by springs and energy is only required to release the clamping.
• For personnel and load protection applications, it should be checked whether such a safety principle is required or prescribed.
• Clamping units are available with different actuation systems.
• Pneumatic systems offer fast switching times, simple integration and economical operation.
• Hydraulic systems offer very high clamping forces, high rigidity and suitability for heavy-duty applications.
• Electric systems offer simple connection to modern control systems and good monitoring options.
• The choice should be based on the machine's existing infrastructure.
• Short reaction times are crucial for safety applications. Especially with fast-moving axes, the reaction time determines the actual protective effect of the clamping unit.
• Clamping units as safety devices often have to comply with normative requirements.
• Important regulations are Machinery Ordinance or Machinery Directive EN ISO 13849, IEC 62061, EN 60204-1, EN ISO 14119 and EN ISO 12100.
• The purchasing department should check whether the clamping unit has been certified for safety-related applications and which safety parameters are available.
• The operating environment has a considerable influence on the service life and reliability. Depending on the area of application, special protective coatings or stainless steel versions may be required.
• Clamping units are subject to mechanical stress and wear. A long service life reduces downtime costs and increases the economic efficiency of the system.
• Modern clamping units often have integrated sensors.
  Possible functions include open/closed detection, wear monitoring, status diagnostics and the output of error messages and safety queries. These functions facilitate integration into Industry 4.0 concepts and increase system availability.
• The clamping unit must be compatible with the existing machine control system. Problem-free integration reduces commissioning times and avoids subsequent adaptation costs.
• As clamping units are often installed in places that are difficult to access, attention should be paid to a maintenance-friendly design.
• Clamping units are safety-relevant components, so the manufacturer should be selected carefully. A competent manufacturer can help to avoid wrong decisions as early as the planning phase.
• The purchase price should never be the sole selection criterion. A higher-quality solution often proves to be significantly more economical over the entire life cycle.

The professional purchase of clamping units requires a comprehensive evaluation of technical, safety-related and economic criteria. Particularly important are the correct design for the actual loads, the selection of a suitable safety principle, compliance with relevant standards and compatibility with the existing command and control systems. Response times, service life, diagnostic options and the quality of the manufacturer also play a decisive role. Companies that systematically take these factors into account create the basis for safe, reliable and economical machine and system concepts.

Clamping units can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Clamping units from all over the world can be found on Exportpages.