Knuckle-joint presses have longer slide stroke

A modified drive on Schuler knuckle-joint presses give longer slide stroke and enable fast and flexible production of a wide range of parts owing to more die mounting space.

Knuckle-joint presses enable fast and flexible production of a wide range of parts for mostly flat parts.

Now that high-strength steels are being increasingly used and formed into complex geometries more space is generally needed in the press.

Conventional automatic blanking and forming presses with knuckle-joint drives soon reach their limits, said Schuler Systems.

Schuler therefore developed a a modified 'Quick Lift System' drive to provide more space in the die mounting area of the press and so expand knuckle-joint press applications.

The available space in the die mounting area of the press can be a limiting factor for the use of knuckle-joint presses, said Schuler to manufacturingtalk.

The 'rule of thumb' was: stroke height of the die mounting area divided by three equals maximum part height.

With a modified knuckle-joint drive, Schuler subsidiary Graebener Pressensysteme has now developed a novel solution, which combines the benefits of the knuckle-joint press with the longerslide stroke of eccentric presses.

* Quick-Lift drive - Schuler's 'Quick-Lift' system provides up to 500mm of additional slide stroke.

The press performance is not affected, as it is purely a lifting stroke in the top dead centre (TDC) level of the slide.

With the aid of servo motors, a lever is swiveled to raise the slide in the load-free area.

Thanks to the space gained, higher parts can now also be moved by the press transfer system through the die mounting area.

For the forming operation itself, the slide movement corresponds to the tried and trusted technology.

* Forming high-strength steels - the benefits of the new drive technology are particularly relevant for the forming of automotive high-strength steels, said Schuler.

The challenge in producing such parts in these steels is the various forces needed to form the material.

This is where knuckle-joint technology boasts clear advantages.

Due to the high rigidity of the overall system, off-center loads pose no problems.

The precision of the slide movement guarantees utmost part quality and the optimised adjustment of the slide speed in the bottom dead center minimises material strain - thus reducing the danger of stress cracks after the forming operation.

For the user, this means greater process reliability and excellent part quality and maximum line availability.

* Knuckle-joint press reliability - the high level of process reliability is guaranteed by the 'tried and trusted' technology of knuckle-joint presses.

Schuler said that ver 90% of parts used in the latest presses are largely unchanged.

The real innovation is in the drive technology.

The automatic blanking and forming presses fitted with Quick Lift functionality represent an ideal addition to the existing machine base, while at the same time offering more investment security.

The tmachine concept has been proving its worth for some 20 years now on a daily basis.

Schuler said that operators and developers are well acquainted with the basic technology and the new drive concept also expands machine use considerably for future applications.

Wherever ready-to-assemble parts with greater heights are required, these can now be manufactured far more economically.

Moreover, it is also possible to carry out several steps on one knuckle-joint press - such as drawing, bending, embossing, blanking and calibrating - and to combine them with each other.

* About the Schuler Group - Schuler supplies machines, production lines, dies, process know-how and services for the entire metal-working industry.

The company's most important clients include car manufacturers and their suppliers, as well as companies in the energy, electrical and household equipment industry.

Schuler is also the market leader in coin minting technology.

Headquartered in Goeppingen, Germany, the company is represented in over 20 nations around the world.

The Schuler Group is one of Germany's oldest industrial enterprises and can trace its roots back to a locksmith shop founded by Louis Schuler in 1839.

Schuler subsequently emerged as the international flagship company in the metalforming equipment industry.

In addition to its numerous foreign subsidiaries, the Schuler Group also comprises Mueller Weingarten, which it acquired in April 2007.

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