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Ratio-Clamp Rod-Locking Device FAQs

The Ratio-Clamp is a rod-locking device that is used both for precise locking and for securing against unintentional movements. It uses the principle of frictional contact to do so. When the releasing pressure drops, the force stored in the springs is discharged, causing the rod to clamp through friction. This means no power is needed to hold the position. To unclamp, hydraulically release pressure to release the clamping force.

The Ratio-Clamp has a max holding load of 101,164 lbf (450 kN) and covers rod diameters from 0.709 inches (18 mm) to 5.512 inches (140 mm).

Talk to an engineer about your application or configure your own Ratio-Clamp using our online configurator.

The Ratio-Clamp is approved by the German Technical Inspection Agency (TÜV). For more information on Ratio-Clamp as a certified safety device, reach out to our engineers.

The Ratio-Clamp holds the exact position when releasing pressure drops, while the safety catcher, due to its self-energizing principle, experiences some movement before fully stopping. This makes the Ratio-Clamp the better choice in applications where exact positioning is important, such as testing and simulation. Additionally, the Ratio-Clamp can perform on horizontal axles as well as vertical in both directions, while the safety catcher can only be used on gravity-loaded vertical axes in one direction (down).

Hydraulic Cylinders — Rod-Locking Device

The Hänchen Ratio-Clamp® keeps the position for you. This device is a positive rod clamping safety device. The Ratio-Clamp is unlocked by hydraulic pressure. In the event of an electrical/hydraulic power loss, the potential energy of the internal Bellville washers load a conical piston, driving it over the friction fingers resulting in securing the load. “A true self contained safety clamp.”

Wherever power failures or malfunctions pose a risk to the safety of people or machinery, the rod locking device is there to save the day. It is also useful to accurately hold the cylinder rod in an exact position without the need to keep hydraulic pressure on the cylinder, thereby saving energy while maintaining accuracy. It clamps down and fixes the piston rod right where it is with no additional power needed.

Advantages of hydraulic rod locks

No axial rod movement during clamping and releasing
Protective clamping effect in case of a power failure
Load capacity that is independent of direction
Clamps completely surrounding rods
IoT 4.0 Compatible: Integrated sensors to know if the clamp is locked or unlocked

Boasting a retention force of up to 101,000 lbf., the clamp hydraulically holds the piston rod in whatever position it is in at that particular moment without having to generate extra power (no extra energy) for an unlimited period of time. The clamping device Ratio-Clamp is approved by the German Technical Inspection Agency (TÜV).

Special development of Custom solutions (larger rod diameters, intermediate size, greater clamping forces) pose no problem for the Hänchen specialists. Hänchen is particularly proud of its RC-H model. Following a request from the Health and Safety Centre of the Employers’ Liability Association (BGZ iron and metal section III, Düsseldorf), Hänchen developed the new safety clamping hydraulic Ratio-Clamp under extreme conditions for use with hydraulic presses and injection molding machines.

Comparison of Fixation Options for Round Rods

	Electronic Control	Port Lock-Off	Pivot Pin Locking	Clamping Unit Ratio-Clamp®
Energy Efficient	–	+	+	+
Position Accuracy	+	–	+	+
Independence from external influences	+	–	+	+
Effort	–	+	–	+
Flexible positioning	+	+	–	+

Technical Data

	Releasing Pressure	Locking	Sealing System	Certification
Ratio-Clamp	Basic design	Reduced design	Basic design	Basic design
Ratio-Clamp (Reduced Releasing Pressure)	With spring power	With spring power	With spring power	With spring power
Ratio-Clamp (Pressure Piston Seal)	Servocop®	Servocop®	Pressure Piston Seal	Servocop®
Ratio-Clamp (As a Safety Component)	TÜV	TÜV	TÜV	TÜV, DGUV Test

Rod Ø (in) \| [mm]	Max. Holding Load (lbf) \| [kN]	Releasing Pressure Min. (psi) \| [bar]
0.630 [16]	2248 [10]	870 [60]
0.709 [18]	2810 [12.5]	797 [55]
0.787 [20]	3147 [14]	797 [55]
0.866 [22]	3821 [17]	1015 [70]
0.984 [25]	4496 [20]	1015 [70]
1.102 [28]	7082 [31.5]	1305 [90]
1.181 [30]	8992 [40]	1522 [105]
1.260 [32]	8992 [40]	870 [60]
1.417 [36]	10124 [45]	1087 [75]
1.575 [40]	11240 [50]	1160 [80]
1.772 [45]	14612 [65]	1015 [70]
1.969 [50]	17984 [80]	1305 [90]
2.205 [56]	20232 [90]	1087 [75]
2.362 [60]	22480 [100]	1087 [75]
2.480 [63]	22480 [100]	1232 [85]
2.756 [70]	31473 [140]	1160 [80]
3.150 [80]	40465 [180]	1305 [90]
3.543 [90]	44961 [200]	942 [65]
3.937 [100]	56201 [250]	1087 [75]
4.331 [110]	67442 [300]	942 [65]
4.724 [120]	74186 [330]	1015 [70]
4.921 [125]	78783 [350]	1087 [75]
5.512 [140]	101164 [450]	942 [65]

Rod Ø (in) \| [mm]	Max. Holding Load (lbf) \| [kN]	Releasing Pressure Min. (psi) \| [bar]
0.630 [16]	1798 [8]	725 [50]
0.709 [18]	1798 [8]	507 [30]
0.787 [20]	2023 [9]	580 [40]
0.866 [22]	2697 [12]	652 [45]
0.984 [25]	3372 [15]	725 [50]
1.102 [28]	5620 [25]	942 [65]
1.181 [30]	6744 [30]	1087 [75]
1.260 [32]	6744 [30]	652 [45]
1.417 [36]	7193 [32]	725 [50]
1.575 [40]	8542 [38]	797 [55]
1.772 [45]	10116 [45]	725 [50]
1.969 [50]	12364 [55]	870 [60]
2.205 [56]	13488 [60]	725 [50]
2.362 [60]	15736 [70]	797 [55]
2.480 [63]	13488 [60]	797 [55]
2.756 [70]	22480 [100]	797 [55]
3.150 [80]	29225 [130]	942 [65]

Rod Ø (in) \| [mm]	Max. Holding Load (lbf) \| [kN]	Releasing Pressure Min. (psi) \| [bar]
0.709 [18]	2810 [12.5]	1087 [75]
0.787 [20]	3147 [14]	1087 [75]
0.866 [22]	3821 [17]	1305 [90]
0.984 [25]	4496 [20]	1305 [90]
1.102 [28]	7081 [31.5]	1740 [120]
1.181 [30]	8992 [40]	1957 [135]
1.260 [32]	8992 [40]	1305 [90]
1.417 [36]	10116 [45]	1450 [100]
1.575 [40]	11240 [50]	1450 [100]
1.772 [45]	14612 [65]	1305 [90]
1.969 [50]	17984 [80]	1595 [110]
2.205 [56]	29232 [90]	1450 [100]
2.362 [60]	22480 [100]	1450 [100]
2.480 [63]	22480 [100]	1595 [110]
2.756 [70]	31473 [140]	1595 [110]
3.150 [80]	40465 [180]	1595 [110]
3.543 [90]	44961 [200]	1232 [85]
3.937 [100]	56202 [250]	1377 [95]
4.331 [110]	67442 [300]	1305 [90]
4.724 [120]	74186 [330]	1305 [90]
4.921 [125]	78783 [350]	1305 [90]

Rod Ø (in) \| [mm]	Max. Holding Load (lbf) \| [kN]	Permissible load per the DGUV Test (lbf) \| [kN]	Releasing Pressure Min. (psi) \| [bar]
0.709 [18]	2810 [12.5]	1405 [6.25]	797 [55]
0.787 [20]	3147 [14]	1573 [7]	797 [55]
0.866 [22]	3821 [17]	1910 [8.5]	1015 [70]
0.984 [25]	4496 [20]	2248 [10]	1015 [70]
1.102 [28]	7081 [31.5]	3539 [15.75]	1305 [90]
1.181 [30]	8992 [40]	4496 [20]	1522 [105]
1.260 [32]	8992 [40]	4496 [20]	870 [60]
1.417 [36]	10116 [45]	5058 [22.5]	1087 [75]
1.575 [40]	11240 [50]	5620 [25]	1160 [80]
1.772 [45]	14612 [65]	7306 [32.5]	1015 [70]
1.969 [50]	17984 [80]	8992 [40]	1305 [90]
2.205 [56]	29232 [90]	10116 [45]	1087 [75]
2.362 [60]	22480 [100]	11240 [50]	1087 [75]
2.480 [63]	22480 [100]	11240 [50]	1232 [85]
2.756 [70]	31473 [140]	15736 [70]	1160 [80]
3.150 [80]	40465 [180]	20232 [90]	1305 [90]
3.543 [90]	44961 [200]	22480 [100]	942 [65]
3.937 [100]	56202 [250]	28101 [125]	1087 [75]
4.331 [110]	67442 [300]	33721 [150]	942 [65]
4.724 [120]	74186 [330]	37093 [165]	1015 [70]
4.921 [125]	78783 [350]	39341 [175]	1087 [75]
5.512 [140]	101164 [450]	56202 [250]	942 [65]

Ratio-Clamp Applications

Testing technology in aviation: The setups for aviation tests have been refined to the last detail. Cylinders are used in different fields of testing, simulating ambient conditions and loads during different flight phases. The Ratio-Clamp® is used to protect the intricately constructed and expensive systems.
Production in molding and injection presses: Clamping units ensure safety during the pressing process in molding and injection presses for the production of synthetic and rubber molder parts in accordance with EN 289.
Maintenance in railway technology: During maintenance, trains must be fixed in a raised state. The Ratio-Clamp® is ideally suited for this purpose, as it holds the train securely in position until the work had been completed.
Production in grinding machines: During the production process of ICE rail sleepers, extremely large and heavy concrete workpieces must be positioned for grinding safely and with an accuracy of 0.01 mm. Hänchen’s hydraulic cylinders and Ratio- Clamp® clamping units are designed exactly for these requirements.
Production in profilling machines: Hänchen clamping units ensure precise machining and consistent quality in the production of metal profiles. During the production process, they facilitate the machining of the profiles by locking the forming tools in place. Ecological and efficient, purely with spring power.

IC-Fluid Power supplies Hänchen rod-locking devices for hydraulic cylinders and press applications across construction, mechanical, technological, and industrial uses.

Ratio-Clamp Rod-Locking Device FAQs

Hydraulic Cylinders — Rod-Locking Device

Advantages of hydraulic rod locks

Comparison of Fixation Options for Round Rods

Technical Data

Ratio-Clamp Applications

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