• Germany's news in English

Techno trousers get smart enough to switch off chainsaw in emergency

Michael Dumiak · 21 Sep 2011, 08:07

Published: 21 Sep 2011 08:07 GMT+02:00

Facebook Twitter Google+ reddit

The average cut from a chainsaw is deep, ragged and takes 110 stitches to close: currently the protective trousers to save legs from such injuries are heavy and hot, making tree work uncomfortable and difficult.

Researchers at the Hohenstein Institute and the University of Bremen hope hope their solution will be able to tackle both of these problems.

They have lined their trousers with sensors which are triggered by the approaching saw – and turn it off. Prototypes are already being tested in the field – or in the forest.

“We’ve successfully integrated the sensors into clothing. We’d like to improve the washing cycles, especially for industrial care,” said the Institute’s Dr. Jan Beringer, director of the Department of Textile Services and Innovations at the privately-run textile and consumer products research organisation, based in a restored castle off the Neckar River near Stuttgart.

The system works by having switch contacts weaved into throughout the trouser fabric: the contacts, each a few centimetres long and hermetically sealed, contain highly sensitive fibres or “reeds” which sit a small gap apart from one another.

The fibres need a magnet to connect them, at which point they activate a switch to send a radio signal to switch off the chainsaw.

The magnet to connect them is contained in the guide bar of the saw – so as soon as it gets too close to the trousers, it connects the fibres in the trousers which switches the buzzing saw off.

The radio transmitter is battery-operated, and if the battery level falls below an effective charge, the power saw is also switched off so the user can change batteries.

The researchers built the trousers for wearers moving around in heavy labour; the sensor-laden textile is lightweight, robust and smooth. And despite Beringer’s desire to further improve laundry performance, tests already show they can be washed many times without affecting the sensor system.

Former tree surgeon Tim Hayford bears a 15-centimetre scar on his leg from where a chainsaw ripped through the conventional protective trousers he was wearing while up a tree. The saw caught a faulty seam which then tore, exposing his flesh to the blade.

But you can count Hayford as a sensor-trousers skeptic. “Chainsaw trousers which are not faulty should protect you in most cases as it is,” the Briton told The Local from his farm in Devon, UK.

“The trouble [with conventional protective trousers] is that they are very heavy and stiff and you get very hot with them. This new idea would be attractive if it would allow you to wear lighter-duty trousers, but I’m not sure you would want to trust an electronic signal completely.”

Hayford figures if his trousers were not defective, he would have been protected.

German forestry workers sustained some 17,300 job-related injuries in the decade from 1999 to 2009, according to statistics from the Board for Forest Work and Technology. This is in a workforce which is currently pegged at about 25,000; in a typical year about 5 percent of the workers would receive some kind of injury, mostly from falling branches.

Story continues below…

About 20 percent of German forest-related injuries are cuts, according to the board. The last such injury survey taken by the United States Consumer Products Safety Commission counted 28,500 total chainsaw injuries in 1999; 36 percent of which were injuries to the legs or knees.

Hayford’s other objection is that the sensor might be too much—it is set to go off somewhere between five and 10 cm close in to the user’s legs. “In some circumstances you might be in a tiny space and it might be extremely frustrating if the saw cuts off all the time,” he said.

But he does figure that if the problem is a nasty, out-of-control approach from the chainsaw, the sensor-controlled brake could be useful. This out-of-control business can happen during a chainsaw “kickback” — when the teeth of the saw catches on something while rotating around the tip of the blade—which is the largest single cause of injuries from chainsaws every year.

Beringer says that the sensor field is adjustable and while no system can be 100 percent, tests show the protective sensor trousers can be 99 percent effective and deliver lightweight protection. While most chainsaw injuries happen to professional foresters, 3.4 million of which work in Europe alone, hundreds of thousands of saws are sold every year on top of that to private buyers.

The researchers face just one more snag in reaching that market—finding a chainsaw manufacturer as a partner to go with the trousers.

Michael Dumiak (news@thelocal.de)

Facebook Twitter Google+ reddit

Your comments about this article

19:12 September 21, 2011 by rfwilson
The problem here is that the "switches" in question (commonly known as "reed switches") are (and must be) enclosed in a small, hermetically sealed glass tube, and thus are extremely brittle. It is doubtful that they could withstand the rough treatment that would occur in the field.
20:06 September 21, 2011 by Englishted
Never mind that.

How about making them not so loud ,not for the people using them but the rest of us.
Today's headlines
Eurowings braces as cabin crew union proclaims strike
Photo: DPA

A union representing cabin crew for Lufthansa's budget airline Eurowings announced that strikes could take place at any time over the next two weeks, starting on Monday.

Mysterious German U-boat wreckage found off Scotland
Photo: ScottishPower

First World War U-boat "attacked by sea monster” thought to be found off Scottish coast.

Supermarket Edeka warns of exploding apple juice bottles
Photo: DPA

"Risk of injury" from "Gut und Günstig" sparkling apple juice bottles has forced Germany's largest supermarket to recall the product.

By wheelchair from Syria to Germany: teen's story of hope
Nujeen Mustafa. Photo: HarperCollins-William Collins Publicity/Private

She tackled the gruelling 2,000-kilometre migrant trail in a wheelchair, translating along the way for other refugees using English she learned from a US soap opera. Now this teen is living in Germany and hoping to inspire others with a newly published memoir.

Berlin Zoo to have a pair of pandas by next summer
A recently born panda pair at Vienna Zoo. Photo: DPA

The giant bamboo-eating bears will move into a brand new 5,000 square-metre enclosure in the capital's Zoologischer Garten.

Two new spider species discovered in Munich
Zoropsis spinimana. Photo: rankingranqueen / Wikimedia Commons

It's news every arachnophobe in Munich is no doubt thrilled to hear: two types of spider new to the region have been discovered in the Bavarian capital - and one of them bites!

After woman's body found in barrel, husband may walk free
Franziska S., who went missing 24 years ago. Photo: Hanover police.

A woman disappeared in Hanover 24 years ago, but no one reported her missing. Although her husband has now confessed to her murder, he still may not step foot in jail.

Two injured after army tank falls 50 metres in Alps
A Bundeswehr Puma tank. File photo: DPA

A Bundeswehr (German army) soldier has been severely injured after the tank he was riding in crashed 50 metres down an embankment after going off course in bad weather.

Teen girl stands trial for 'Isis' police stabbing in Hanover
Police guard the courthouse in Celle. Photo: DPA

A teenage girl stands trial from Thursday in Germany for stabbing a police officer, an assault allegedly "ordered" by Isis but which was not claimed by the jihadist group.

Merkel threatens Putin with more sanctions on Berlin visit
Angela Merkel and Vladimir Putin in Berlin. Photo: DPA

Chancellor Angela Merkel created a united front with French President Francois Hollande in Berlin on Thursday to denounce Russia’s “war crimes” in Syria.

Sponsored Article
How to vote absentee from abroad in the US elections
10 things you never knew about socialist East Germany
Sponsored Article
Last chance to vote absentee in the US elections
How Germans fell in love with America's favourite squash
How I ditched London for Berlin and became a published author
Sponsored Article
How to vote absentee from abroad in the US elections
12 clever German idioms that'll make you sound like a pro
23 fascinating facts you never knew about Berlin
9 unmissable events to check out in Germany this October
10 things you never knew about German reunification
10 things you're sure to notice after an Oktoberfest visit
Germany's 10 most Instagram-able places
15 pics that prove Germany is absolutely enchanting in autumn
10 German films you have to watch before you die
6 things about Munich that’ll stay with you forever
10 pieces of German slang you'll never learn in class
Ouch! Naked swimmer hospitalized after angler hooks his penis
Six reasons why Berlin is now known as 'the failed city'
15 tell-tale signs you’ll never quite master German
7 American habits that make Germans very, very uncomfortable
Story of a fugitive cow who outwitted police for weeks before capture
Eleven famous Germans with surnames that'll make your sides split
The best ways to get a visa as an American in Germany
jobs available
Toytown Germany
Germany's English-speaking crowd