The patented clamping device Ratio-Clamp® hold the rod in a standstill and locks it into position mechanically. The clamping effect is immediate, lasts for an unlimited period of time and doesn't require an energy supply – suitable for various applications, as a safety element or for locking component parts into place. 100% reliable! If necessary, we can also develop a customized solution for you.
Application areas of the hydraulic clamping device:
There are many situations where rods have to be held in a certain position: For example to protect people, machines and tools in case of power failures or plant shutoffs. Or to fix axes during a manufacturing process. And also for all highly dynamic applications and test processes.
Here are some examples from practical experience:
Hänchen hydraulic cylinders and Ratio-Clamp® clamping devices are perfect for casting machines because they must be precise as well as particularly resistant to heat and corrosion. Ratio-Clamp® hydraulic rod clamps hold the mould parts safely together during the casting process of aluminum motor blocks.
Hänchen hydraulic cylinders with fitted Ratio-Clamp® clamping devices are used for moving the bow and stern doors of ferries. The hydraulic rod clamps guarantee that the doors are tightly closed during the voyage and safely locked while passengers are embarking or disembarking.
Trains need to be lifted and fixed for maintenance – Ratio-Clamp® devices are perfect for this. The hydraulic rod clamp will keep the train safely in place until the work is done and it can get back on the tracks.
The setups for aviation tests have been refined to the last detail. Hänchen hydraulic cylinders are used in different fields of testing, simulating ambient conditions and loads during different flight phases. Ratio-Clamp® hydraulic clamping devices are used to protect the intricately constructed and expensive systems.
During the production process of ICE track beds, extremely large and heavy concrete workpieces must be positioned for sanding safely and with an accuracy of 0.01 mm. Hänchen's hydraulic cylinders and Ratio-Clamp® clamping devices are designed exactly for these requirements.
Hänchen's Ratio-Clamp® offers safety while saving energy costs. Thanks to its sophisticated functional principle, the hydraulic clamping device features some fundamental advantages when compared with other locking systems.
Ratio-Clamp® rod locks works mechanically by using frictional contact: The power is directed through springs to a clamping sleeve which holds the rod radially using friction. The load capacity of the fixation is not influenced by the direction. The hydraulic releasing pressure moves the locking piston against the spring power to unlock the clamp - the rod can be moved in both directions. When the hydraulic pressure drops, the power stored in the springs is released, and the rod is locked.
Right in the video, the functional principle of the clamping device on the example of a gantry milling machine.
Do you need a round rod locked in a specific position? There are several ways to do this: Electronic control, blocking all ports or using the hydraulic clamping device Ratio-Clamp®. Ratio-Clamp® features a number of advantages.
|Blocking ports|| Clamping device
|Energy efficiency|| –
|Accuracy of position|| +
|Independence of external factors|| +
|Time and effort|| –
Regardless of hydraulics and electronics, Ratio-Clamp® will hold the piston rod in any position for any amount of time – no energy supply required.
A hydraulic cylinder with an 80 mm bore is moved at 150 bar with a speed of 0.5 m/s. The drive power required is 38 kW.
Power loss when holding
When using an electronic control system with a controlled pump, the power loss to be expected at the pump is approx. 1.25 kW, plus a loss of approx. 1.25 kW at the control valve. So in this example, the total power loss with the controlled drive would be 2.5 kW. With a holding time of 5.000 hours a year, you'd lose 12.000 kWh.
Ratio-Clamp® uses spring power for holding, which is why there is no need for hydraulic or electric power.
The basic release pressure required for releasing the rod clamping device is between the minimum pressure and the maximum admissible pressure of 160 bar.
For application cases with low supply pressure, a version designed with a reduced released pressure is available.
Ratio-Clamp® is certified by TÜV SÜD as a safety element.
The hydraulic clamping device is also available with a DGUV Test certification (testing
and certification system of the Deutsche Gesetzliche Unfallversicherung). learn more
Locking with spring power
Usually, energy stored in springs is used to clamp a rod. This means that the rod can be held for unlimited periods of time without any energy supply.
When very high holding loads are required, the clamping device can also be locked hydraulically. For the release, hydraulic pressure is used as usual.
Servocop®: compact seal, lip seal, wiper ring
The basic type of Ratio-Clamp® uses the friction-optimized sealing system Servocop®. Here, the primary seal is touching the rod. The maximum speed of the rod is 1 m/s.
Pressure piston seal, lip seal, wiper ring
For very sensitive applications, we recommend the design with pressure piston seal, where no pressurized seal is touching the rod. Thus, the sliding friction is very low and remains constant regardless of the releasing pressure. The maximum speed of the rod is 2 m/s. learn more
Ratio-Clamp® can be combined with Hänchen hydraulic and standard cylinders and with all cylinders from other manufacturers.
Indicates whether the clamping device is locked released.
Used when Ratio-Clamp® is installed on a hydraulic cylinder. It provides correct and consistent control and thus reduces the complexity of the required wiring.
Technical information Clamping device Ratio-Clamp®
Here you find further informations about principle of operation, selection and functional test of hydraulic clamping device Ratio-Clamp®.
Other holding loads & rod Ø on request