Overview

The KOBRA MK1-SS is a compact stainless steel safety interlock switch designed for position detection on small moving machine guards such as sliding, hinged, or lift-off types. It is especially suited for hygienic environments like food processing due to its mirror-polished stainless steel finish (RA10).

Key Features

• Compact design: 30mm wide with 22mm fixing centers and rotatable head allowing up to 8 actuator entry positions.
• Rugged stainless steel 316 actuator profile with mirror-polished finish for durability and hygiene.
• Flexible plastic actuator option available for tight radius guards.
• Replaceable contact blocks for easy maintenance.
• IP69K rated for high protection against water and dust ingress.

Functional Specifications

• Positive break contacts compliant with EN60947-5-1.
• High functional safety meeting ISO13849-1 standards, capable of up to PLe Cat.4 safety level depending on system architecture.
• 3-pole switch configuration (2 normally closed (NC), 1 normally open (NO)).
• Compatible with most safety relays.
• Standard dimensions: 98mm length, 30mm width, 22mm fixing centers.

Electrical and Mechanical Data

• Contact ratings: Thermal current 5A, Utilization category AC15 A300 3A.
• Rated insulation voltage: 600Vac; withstand voltage: 2500Vac.
• Mechanical reliability: B10d rating of 2.5 million operations at 100mA load.
• Safety reliability data: PFHd 3.44 x 10^-8, MTTFd 356 years, proof test interval 35 years.
• Travel for positive opening: 6mm.
• Maximum actuator approach/withdrawal speed: 600mm/s.
• Vibration resistance: IEC 68-2-6 standard, 10-55Hz + 1Hz, 0.35mm excursion.

Connection Options

• Quick Connect (QC) options: M12 8-way male connector or flying lead (250mm).
• Available cable lengths: 5m and 10m M12 8-way leads.
• Gold plated contacts option for low power circuits (5V, 5mA).

Standards Compliance

• ISO14119 (Safety of machinery - Interlocking devices associated with guards).
• EN60947-5-1 (Control circuit devices and switching elements).
• EN60204-1 (Safety of machinery - Electrical equipment).
• ISO13849-1 (Safety-related parts of control systems).
• EN62061 (Functional safety of electrical/electronic/programmable electronic safety-related systems).
• UL508 (Standard for industrial control equipment).

Installation and Mounting

• Mounting position: Any orientation.
• Fixing: 2 x M4 screws.
• Body material: Stainless Steel 316 with mirror polish.
• Rotatable head with 8 actuator entry positions for flexible installation.
• Recommended use of Stainless Steel 316 gland for conduit entry.
• Optional Stainless Steel Guide accessory for guard alignment.

Application Example

The MK1-SS can be used in dual-channel interlock circuits for guard doors, providing direct feed to contactor coils with feedback monitoring. Opening the guard or pressing Emergency Stop isolates power, ensuring machine safety. Restart is only possible when the guard is closed and Emergency Stop is reset.

Ordering Information

• Base switch with 2NC 1NO contacts: Sales numbers 224001 (M20), 224002 (1/2" NPT), 224003 (QC M12 8-way).
• Actuator options: Flat (add 'F'), Angled (add 'A'), Plastic Flexible (add 'PF').
• Gold plated contacts: Add '-GC' suffix.
• Stainless Steel gland: M20 (140120), 1/2" NPT (140121).
• Stainless Steel Guide: 140179-SS.

Critical Parameters and Limitations

• Minimum actuator entry radius: 150mm standard, 100mm with flexible actuator.
• Maximum approach/withdrawal speed: 600mm/s.
• Designed for 8 cycles per hour continuous operation.
• Proof test interval of 35 years under specified usage conditions.

Summary

The KOBRA MK1-SS safety interlock switch is a robust, hygienic, and compact solution for machine guard position detection, offering high safety integrity levels and flexible installation options. Its stainless steel construction and IP69K rating make it ideal for demanding environments such as food processing. The product supports multiple actuator types and connection options, ensuring adaptability to various machine safety applications.