Leading Manufacturer of Safety Interlock Switches and Machine Guard Safety Switch Devices for Automation and Process Safety

Mechanical Trapped Key Interlocking Devices (Stainless-Steel)

IDEM’s Trapped key interlocks utilise locks and coded keys for sequential control of equipment and machinery to ensure safe operation. Trapped key interlocks are widely used to ensure safe access to potentially live or dangerous plant or equipment in an industrial setting.

  • 316 Grade Stainless Steel
  • Robust with High Mechanical Integrity
  • Comprehensive Range
  • Thousands of Mechanical Key Codes
  • Suitable for IP69K Requirements
  • Suitable for SIP/CIP Cleaning

what to consider when designing a trapped key system:

Stage 1: Isolation

The first stage of any trapped key system is to isolate the power or control circuit. This should STOP any hazardous processes associated with the zone you are trying to access.

Stage 2: Key Exchange

The second stage is exchange. The isolator keycan be used to open 1 access lock at a time or, if there are multiple access locks, a key exchange can be used.

Stage 3: Access Control

Access locks prevent entry to the hazardous areas. Only when the correct coded key is presented, will entry be permitted.

Stage 4: Personnel Key

The personnel key is predominately used in full body access situations, allowing the user to operate safely inside the hazardous area.

Stainless Steel Trapped Key Interlock Process

Stage 1: Isolation

The first stage of any trapped key system is to isolate the power or control circuit. This must STOP any hazardous processes associated with the area you are trying to access.

Power Isolation

Turning and removing the key isolates the power up to 63A. Available in pane or box mount options depending on your requirements.

Power Isolation with Solenoid Controlled Key Release

The solenoid holds the key in place to enforce a run-down, allowing time for the hazard to be removed. Turning and removing the key isolations the power up to 63A.

Control Switch Isolation

Isolate the control circuit using a key switch. Turning the key activates the internal contact block, sending a stop signal to the safety controller. This is the most common method of isolation for modern applications.

Control Switch Isolation with Solenoid Controlled Key Release

The solenoid holds the key in place, enforcing a rundown time until the hazard has been removed. Turning the key triggers the internal contact block, sending a stop signal to the safety monitoring device.

Mechanical Isolation of Switchgear

IDEM mechanical interlocks mount directly to electrical equipment and act as a physical barrier to electrical switches and power buttons, ensuring the state of power cannot be mistakenly changed.

Stage 2: Key Exchange

The second stage is exchange. The isolator key can be used to open 1 access lock at a time or, if there are multiple access locks, a key exchange can be used. Depending on your requirement, there are different types available, ranging from simple to complex systems.

Trapped Key Vertical Key Exchange System in Stainless Steel

Vertical Key Exchange System

The vertical key exchange system is available with 1 key in and up to 9 keys out. The slim line design is simple to mount, perfect for when space is a premium.

Multi-Key MX Exchange Panel

The multi-key exchange system is available for larger, more complex requirements. There are three types available: 8-key, 12-key and 20-key panels with options box mount.

Control Switch and Key Exchange Combined

The CS-Range combines control switch isolation and key exchange, providing a highly configurable key exchange system that mounts directly to your panel.

Stage 3: Access Control

The third stage is access control. Access locks prevent entry to the hazardous areas, only when the correct coded key is presented will entry be permitted. Depending on your application, we have a range of access interlocks with both single and dual key options.

Single Key Trapped Key Access Interlocks

Single key access locks ensure that a guard or door is locked closed under normal operating conditions.

Dual Key Trapped Key Access Interlocks

Dual key access locks ensure that a guard or door is locked closed under normal operating conditions.The second key (often refered to as the personnel key) should be taken inside the hazardous area to reduce the likelihood of an inadvertent start-up.

Trapped Key Interlock with Solenoid Controlled Key Release

Gate access locks with solenoid controlled key release for enforcing a rundown period.

The release key can be used to aid the prevention of inadvertent start-ups.

Choose Your Key Coding

Thousands of mechanically coded keys available. Custom key labels are available in a range of colours for quick identification.