Over the past few years, master carpenter Andreas Reßle has gradually developed his company, ARS Starkholzplatten, into a fully integrated production site complete with a sawmill, further processing plant, development department, planning team, and in-house carpentry workshop. His own, continuously refined solid wood wall systems still play an important role in this development.
The solid wood wall systems have a middle layer that consists of vertically positioned, unglued mass timber lamellas and top layers made of 9- to 46-mm-thick mass timber panels. Various versions with grooved lamellas in the middle layer or top layers made of beech wood improve the insulation values or increase the load-bearing capacity of the elements.
While the sawmill that was acquired in 2017 was in the ramp-up phase, Reßle built a new joinery hall at the Bavarian site in Roßhaupten in 2021, complete with a high-performance CNC machine and vacuum crane. For the latter, the timber construction specialist opted for a proven, semi-automated solution from Austrian manufacturer Voith. The vacuum crane went into operation in 2022.
Rapid growth
Voith is an expert when it comes to the safe and quick lifting of components, whether they be small or bulky and heavy. The manufacturer, which is based in Traun, Upper Austria, specializes in crane solutions for various industries. While its core business lies in the steel sector, the timber industry has become the company’s second largest business area. Besides crane systems for glulam and lumber, Voith crane solutions can be found in numerous CLT plants around the globe. “We offer manual, semi-automated and fully automated solutions, depending on the application and company size,” Benedikt Stadler, sales engineer at Voith, explains. The cranes handle not only finished panels, but also raw material packages and individual longitudinal and crosswise layers.
In 2022, Voith carried out a crane project at ARS that consists of three hoists that move three vacuum lifting beams. Two of them can be adjusted relative to each other using adjustable trolleys on the main trolley. “This is necessary for the flexible transport of short to very long and heavy elements with lengths of up to 16 m,” Stadler says, adding that the third hoist, along with its associated vacuum lifting beam, was designed for small parts such as door and window cutouts. Furthermore, the system features a turning device for panels and cable-stayed load stabilization mechanism for the safe and precise positioning of the elements. In addition to the infeed to the CNC machine, the crane also handled the loading and unloading of the trucks. “This worked very well right from the start. However, our production volume increased rapidly, and we soon reached the crane’s capacity limit, which is why we contacted Voith again in early 2024,” ARS plant manager Christian Schamper tells us.
A crane for flexible loading
While the first crane is still used to feed in elements to the CNC machine and remove them from it, Voith designed the second crane specifically for truck loading. “ARS had several special requests, which we were happy to implement, as with all our projects,” Stadler emphasizes, giving a clamping device for elements with wood-based materials attached to them and a camera system for each vacuum lifting beam as examples.
Specifically, Voith delivered a combination vacuum loading crane with a deadweight of 27 t and a vacuum lifting capacity of 4.5 t on the main beam. Together with the 1.8-t lifting capacity of the auxiliary beam for smaller components, this results in a total payload of 6.3 t for the vacuum lifters.
Voith equipped the main vacuum lifting unit with 24 vacuum suction plates that make it possible to handle panels with sizes from 600 by 600 mm to 9000 by 3500 mm. For longer panels, ARS uses either the auxiliary vacuum lifting unit or the crane that was delivered in 2022 and that can handle panels with a maximum length of 16 m. For the handling of particularly narrow and long or short and wide panels, the vacuum suction cups are divided into four longitudinal and six crosswise groups, each of which can be switched on and off separately.
The double-girder main trolley, like the single-girder auxiliary trolley, is equipped with cable-stayed load stabilization mechanism in both the crane and trolley travel directions. Since the main trolley travels between the two bridge girders, it can move independently of the other trolley, which is positioned as a cantilever on one side of the main girders. Voith designed two articulated and electrically adjustable lifting stars on the main vacuum unit, allowing the vacuum lifting beam to swivel horizontally. “This is a great feature when loading trucks, especially when the trailer isn’t perfectly parallel to the loading lane. It is also helpful in adjusting the unit to slightly inclined surfaces, such as gable walls,” Schamper tells us.
The auxiliary unit is also equipped with an electric drive that facilitates rotation of up to 270°. Like the first crane, the new machine also features an additional turning device for rotating panels without damaging them. For this purpose, two 200-mm-wide rubber fabric belts, which are driven by reversible wheels, are placed around the panel, causing it to rotate.
Clamping instead of suction
For ARS, Voith developed an additional clamping device specifically for elements that have panels or insulation attached to them and that can therefore not be handled with the vacuum lifting beam. “For this purpose, we attached clamps in a telescopic and height-adjustable design. Positioned slightly inclined and outward, even slightly protruding materials that are attached to the elements remain undamaged,” Stadler says, describing the newly developed solution, and adds that even angled components, such as gable walls, can be lifted thanks to the clamps that can be rotated.
Everything in view
Both cranes are controlled via radio remote control. Thanks to the semi-automatic design, the cranes can automatically move towards predefined positions, such as “Truck Position 2” or “Joinery Left”. Furthermore, the two vacuum lifting beams of the newer crane are each equipped with a camera. The images are transmitted directly to the radio control. “This way, we can precisely position elements anywhere in the hall without having to constantly walk back and forth,” Schamper emphasizes, who is extremely satisfied with the new crane solution. “Voith fulfilled all our requirements, implemented our special requests and once again installed a practical system that equips us perfectly for the challenges of the coming years.”
