Application Report
Experience, tradition and passion
Experience, tradition and passion – these values ensure the five-star quality at the fivebrother company Bühler Bedachungen und Bauspenglerei from Romanshorn in
Switzerland, a business specializing in roofing and architectural sheet metal. Quality is the
top priority for the family business – particularly when it comes to selecting its partners and
suppliers. Among these is the Swiss company Jorns AG, which supplied the new double
bending machine, model TP-150G-RH-UV-SL-1250-CP200-6.4-mp, including safety concept
for the architectural sheet metal area as well as the manufacturer for optical sensors, which
ensures the corresponding safety at work for man and machine, Leuze electronic.
Figure 1: In addition to the Lausanne theater, the gondola station in Wildhaus, the elephant enclosure at the
Rapperswil zoo and the tribune roof in St. Moritz for the Olympics, Chäserrugg is one of many renowned
projects completed by Bühler Bedachungen und Bauspenglerei
Safety for man and machine
Safety for man and machine is required not only by safety-relevant, international
standards. Protecting man and machine from dangerous processes is a matter of course
for the 35-person company. "If a new machine is used, such as the new TwinMatic-Pro
150 bending machine from Jorns here in our architectural sheet metal operations, it must
satisfy the latest requirements on safety technology," says trained sheet metal worker
Bruno Bühler. When selecting the safety concept, he relied on the consulting expertise of
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the manufacturer of this machine, Jorns AG from Lotzwil. Thanks to positive experiences
with other projects, Jorns used the RSL 430 safety laser scanner from Leuze electronic,
which optoelectronically safeguards access to the long, front side of the machine. The
RSL 430 is centrally positioned under the bending basin, ensuring that the maximum
radial range of the sensor can be used. The area in front of the machine can thereby be
safeguarded with just one sensor.
Figure 2: Double safeguarding with RSL 430 safety laser scanner and step bar
Fully automated work process
TwinMatic-Pro 150 is the name of the new bending machine from Jorns AG used in the
architectural sheet metal area of the company, which replaced a nearly 20-year-old
machine with similar functionalities here. The new machine enables the bending of a very
wide range of types and thicknesses of sheet metals in a fully automated process:
aluminum, zinc, copper, steel. Only when loading and removing the metal sheets does
the machine need to be handled manually. As soon as the machine operator crosses the
red line on the floor located approximately 80 cm from the bending machine, thereby
entering the danger zone of the machine, his movement is detected by the RSL 430
safety laser scanner and the machine comes to an immediate standstill. Should this
safety monitor fail, there is a "safety net" in the form of a step bar. If this bar is actuated
by the operator’s foot, it presses against an EMERGENCY-OFF command switch that
brings the machine to a standstill in a fraction of a second. "It’s good to have a double
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safety net – fortunately, we’ve never had to make use of it. The RSL 430 safety laser
scanner works reliably and fault-free, making it the optimum solution for us," says sheet
metal worker Bruno Bühler, who usually operates the bending machine himself.
Figure 3: Sheet metal worker and machine operator Bruno Bühler at the control panel
The functionalities of the new safety laser scanner convince
Due to its innovative capacity, the RSL 400 safety laser scanner – which is available in
various models – convinced not only end users such as Bühler since being launched on
the market at the end of 2015. It also convinced juries of experts, claiming multiple
awards in 2016 – including the GIT Safety Award, the Industriepreis as well as the
Handling Award.
The safety laser scanner functions as follows: it transmits periodic light pulses via a
rotating deflection unit. These are scattered in all directions by obstacles, such as
persons entering the danger zone. A part of the light pulses is received again by the
safety laser scanner and evaluated. The scanner calculates the precise position of the
machine operator from the propagation time of the radiated light and the current angle of
the deflection unit at that time. If this is located within the previously defined protective
field, the safety laser scanner executes a safe switching function. "In our case, this
happens as soon as the machine operator crosses the safety line marked on the floor
with red signal color at the long, front side of the machine," says Pascal Guyot, director of
control engineering at Jorns AG. Should this occur, the safety-related switching outputs
are switched off. The required safety distance is calculated on the basis of safety-related
standard DIN EN 999. Playing a role here are factors such as the approach speed
relevant to safety and height of the protective field above the ground. Furthermore, the
stopping time of the machine as well as additional distances, e.g., for system-related
measurement errors, must also be taken into account.
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Monitoring from a bird’s eye view
All-round protection from all machine sides is, however, not provided by a single safety
laser scanner positioned centrally under the bending basin of the bending machine.
Depending on how they are attached, at least two safety sensors would be needed to
achieve this. With just one safety laser scanner, cutting in automatic mode would only be
possible in inching mode. Obstructions could also occur if the sheet was to protrude far
outside of the machine when bending sheet metal top-down. Bühler therefore decided to
mount a second RSL 430 safety laser scanner to monitor the machine room from above,
thereby reducing the depth of the danger field to 80 cm. The second scanner is attached
to the ceiling with an iron chain and has an operating range of 8.25 meters with a
resolution of 70 mm and a detection range of 270°.
Figure 4: The safety laser scanner monitors from a bird’s eye view
The position of the safety laser scanner is always based on the sensor that monitors the
bending line. Note that the control panel is also detected as an object and must therefore
be located outside of the danger zone while in automatic operation. "If the area of the
control panel were to be removed from monitoring, blind zones would arise within the
danger zone due to shadowing. In addition, blind spots would occur between the stands
and behind the machine, which must absolutely be safeguarded," says Bojan Zmijanjac,
Area Sales Manager at Leuze electronic Switzerland.
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Figure 5: Machine room monitoring with two safety laser scanners
A comprehensive safety concept that convinces
With the positioning of two RSL 430 safety laser scanners, Jorns Bühler recommended
an integrated, comprehensive safety concept for all-round machine protection that has
been proven in practical use and that convinces. Tobias Wüst, managing director of the
Swiss subsidiary of Leuze electronic in Fluringen, emphasizes the competence of the
manufacturer and innovation leader in the area of optical sensors: "Safety sensors have a
great deal to offer. Reliable safety laser scanners require many years of experience. With
the RSL 400 safety laser scanner series, Leuze electronic has succeeded with a
development that combines maximum reliability and performance with simple operation."
Figure 6: Bruno Bühler (Bühler - Bedachungen und Bauspenglerei) and Tobias Wüst
(Leuze electronic) are convinced of the safety concept implemented at Bühler
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About the companies
Jorns AG, Switzerland
The Swiss manufacturer of bending machines, double bending machines, compact strip
cutting lines, gutter machines as well as accessory machines for processing thin sheet
metal, Jorns AG, is a globally active family business specializing in the areas of
architectural sheet metal processing, roofing and hall construction. Jorns AG has more
than 40 years of experience and supports the success of its customers with applicationoriented systems and services for processing thin sheet metal. Focus of the range of
products is the process chain for the cutting and bending of long profiles.
Bühler – Bedachungen und Bauspenglerei AG, Switzerland
Since 1964, Bühler – Bedachungen und Bauspenglerei in Romanshorn, Switzerland, has
stood for outstanding products and services in the areas of roofing, architectural sheet
metal work, facade construction, photovoltaics, scaffold construction and mobile crane
use. Long-standing customers value the technical competence, experience and tradition
of the "five-brother-company" taken over from their father as well as the personal
consulting, support and passion of the complete solution provider.
Leuze electronic
Leuze electronic is one of the world's innovation leaders in optical sensors and is
internationally known as a leading manufacturer and solution provider in electrical
automation. Its main focus is on the areas of intralogistics, packaging industry, tool
manufacturing and automotive industry as well as medical technology. The product range
includes switching and measuring sensors, identification systems, solutions for image
processing and data transmission and also occupational safety components and systems.
Founded in 1963, the company, based in Owen (Germany), possesses specific
application know-how as well as comprehensive industry knowledge. More than 1000
employees at 22 locations are involved in development, production, sales and service –
supported by more than 40 sales partners around the world. Innovative product
developments, tailor-made complete solutions and an extensive range of services stand
for the "Smart Sensor Business 4.0" at Leuze electronic.
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Leuze electronic is one of the world's innovation leaders in optical sensors and is
internationally known as a leading manufacturer and solution provider in electrical
automation. Its main focus is on the areas of intralogistics, packaging industry, tool
manufacturing and automotive industry as well as medical technology. The product range
includes switching and measuring sensors, identification systems, solutions for image
processing and data transmission as well as components and systems for safety at work.
Founded in 1963, the company, based in Owen (Germany), possesses specific
application know-how as well as comprehensive industry knowledge. More than 1000
employees at 22 locations work in development, production, sales and service, supported
by more than 40 sales partners worldwide. Innovative product developments, tailor-made
complete solutions and an extensive range of services stand for the "Smart Sensor
Business 4.0" at Leuze electronic.
Press inquiries
Leuze electronic GmbH + Co. KG, Owen
Martina Schili, Phone +49 7021 573-116
[email protected], www.leuze.com
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