HYGUARD®
Safety Couplings.

Drive performance – with RENK hydraulic safety couplings.
HYGUARD® torque limiting couplings safeguard your machinery’s drivetrain from overload, protecting your capital goods from damage caused by unexpected overstraining. With constant, individually adjustable release torque, the RENK solution ensures reliability and flexibility throughout the entire operation.
Safety couplings are used predominantly in heavy industries such as steel, extrusion, mining, cement, locomotives, and test stands. RENK offers a range of design types to suit your requirements, whether for a new build or installation, or to replace an existing solution. Our broad range of torque-limiting couplings covers capacities of up to 10,000 kNm and speeds up to 7,500 rpm
With over 150 years of expertise, RENK understands your industry inside out. As a global leader in drivetrain technology, we deliver performance, reliability, and innovation.

The HYGUARD® advantages at a glance
- Excellent price/performance ratio (CAPEX)
- Can be combined with all types of couplings
- Quick availability
- No additional energy costs for operation
- Constant trigger torque throughout the entire period of operation
- Torsionally rigid-flexible connection of shafts
- Overload protection with adjustable torque limitation
- Release accuracy of +/- 7–10%
- No stoppages due to material fatigue, resulting in low downtime costs
- No decline in triggering accuracy over time
- Transmission of high torques in a small space
- Quick re-commissioning
- No operational wear and tear, therefore no maintenance costs
- No cost-intensive stocking of spare parts
HYGUARD® torque limiting couplings – easy to operate, reliable in execution.
Appropriate safety equipment is required to protect drivetrains in industrial plants. This includes torque limiting couplings, which are available in a wide range of designs. The HYGUARD® hydraulic safety couplings transmits torque solely by friction between the hydrostatically loaded surfaces of the shaft and hub. It operates without slippage as long as the set torque is not exceeded.
If the torque exceeds this value, the hydrostatic pressure is quickly released, immediately interrupting the driveline. Recommissioning takes very little time. The system simply needs to be pressurised again.
Components of the HYGUARD® torque limiting couplings

- Shaft
- Shear ring
- Injector connection
- Shear tube
- Screw plug for lubricant filling
- Double-walled clamping element
- Seal for lubricant filling
- Coupling hub, gear wheel, or other driving element
Principle of operation
- Two bushes are inserted into each other, both ends of which are closed in a pressure-tight manner.
- The gap gets pressurized with a hand pump.
- Torque is transmitted by frictional engagement between the contact surfaces.
- Torque vs. pressure according to the calibration diagram provided by RENK.
- When the release torque is exceeded, the safety element will slip on the profiled surfaces and the shear ring will cut off the shear tube.
- The pressure drops within milliseconds, and the hydraulic safety coupling releases the connection.
RENK service for your industry

Our industrial services and solutions specialists offer numerous advantages for your projects and plants. These include improving energy efficiency, reducing emissions and costs, and increasing the uptime and safety of your plant. In this we act globally, promptly and throughout the lifecycle of your plant.
Downloads
- RENK Couplings (3.3 MB)
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