The New S Class by Lehnhoff

At the bauma 2016, attachment and bucket specialist Lehnhoff presented its new symmetrical quickcouplers of the SQ series for excavators from 12 to 70 tons in three versions for the first time: the new quickcouplers are based on the open industrial S-standard and are available as mechanical (SQM), hydro-mechanical (SQH), and fully hydraulic (SQE) variants. These couplers allow the immidiate attachment of all symmetric mechanical tools availbale on the market which meet the requirements of the S-standard. As manufacturer of quickcoupling systems, Lehnhoff was the first to succeeded in developing a system that locks fully mechanically.

Due to its approach as a brand-independent attachment specialist, Lehnhoff prevails in the industry as a supplier of all brands. Just now, Lehnhoff has released three new versions of the symmetric quickcoupler. Lehnhoff is currently the only manufacturer of quickcoupler systems offering a fully mechanical version – thanks to a unique self-adjusting locking technology, which proves Lehnhoff’s innovative strength.

All three versions consist of robust, low-maintenance components and feature a safe and self-adjusting locking system with dead-center mechanism. Due to the ingenious combination of a hydraulic actuator and the mechanical dead-center locking, the hydro-mechanical quickcoupler does not require a constant hydraulic locking pressure.

The new SQ quickcouplers are available as mechanical, hydro-mechanical, and fully hydraulic version. They are all based on the open industrial S-standard which was handed out and is managed by the Swedish trade association for suppliers of mobile machines. As with most standards, this one, too, defines uniform size designations as well as a uniform production standard for dimensions and tolerances. This guarantees that all attachments with adapters adhering to the standard are interchangeable. Furthermore, the standard determines that a tiltrotator can be mounted to the machine, that the building height ensures a maximum of breakaway force, and that the quickcoupler itself re-adjusts in case of loosening.

The new quick-change system was developed with regard to these requirements and consists of the quickcoupler and the respective adapter with an inductively hardened coupling shaft. Lehnhoff promises its customers that the right SQ adapter for all attachments is always available - either as adapter frame, as welding adapter or as screw adapter with bore hole pattern.

Both versions, the hydro-mechanical as well as the fully mechanical one, allow locking and unlocking of attachments from the cabin. In addition to that, both variants are available with the safety assistance system Lehmatic Safety Control (LSC), which keeps the operator informed optically as well as acoustically about the locking state at all times.

In comparison to the hydro-mechanical SQ coupler, the fully hydraulic quickcoupler features an additional coupling for the hydraulic lines. The valve block with five symmetrically arranged Lehnhoff short-stroke valves is securely integrated into the housing and allows a reverse mode of attachments by 180°. These valves were designed to ensure a maximum oil flow and lock attachments safely and leakage-free to the working hydraulics. Furthermore, the fully hydraulic SQ coupler is equipped with the unique in-block depressurisation unit which immensely facilitates the installation at the excavator: all relevant valves are integrated in the quickcoupler valve block, and consequently, can be directly depressurized.

Thanks to the new SQ quickcoupler by Lehnhoff, customers are able to continue to use excisting buckets and attachments as well as new buckets or other future attachments, as long as they are based on the S-standard. In combination with the new couplers, the breakout force of the excavator is almost not affected. Additionally, the SQ couplers eliminate any play between the components and make manual readjustment superfluous.