Anyone operating a harvester will testify to how frightening it is when the front windscreen is suddenly struck by a high-speed flying object. This could be from a hung-up branch or a treetop falling from height, stones embedded in the bark of a tree or even chain shot where the chainsaw chain snaps or shatters.
Chain shot is the high velocity separation and ejection of a piece or pieces of cutting chain from the end of a broken chain. A chains cutting speed is normally 40m/sec, but on breaking can accelerate up to 309m/sec (1,112km/hr) almost the speed of sound. Higher chain speeds with attendant power input equates to faster cutting speeds but faster cutting speeds mean increased wear, shorter service life and increased chance of chain breakage and injury.
Researchers estimate that chain shot might occur in 1 in every 50 chain breaks. Harvester chain manufacturers are continually looking at ways to strengthen chains without compromising on performance.
A short while ago I compiled a feature on chain shot with Iggesund Forests cutting equipment specialist Iain Lawrence. “Chain shot is impossible to eliminate” explained Iain “But steps can be taken to reduce the risk. These include good bar, chain, and sprocket maintenance, using a high-quality chain lubrication and the correct chain tensioning. Keeping oil channels free of debris and adjusting chainsaw motors so they maintain the correct chain speed is also important.”
When a harvesting head is crosscutting in line with the harvester the only protection offered to the operator in the event of chain shot or flying debris is the front window. Operating a harvester or forwarder for long hours, five days a week, is tiring on the body and eyes at the best of times. When you throw in shorter daylight hours, dull days with poor daylight and harsh weather conditions, then eyestrain increases tenfold.
The KRD Group from Geesthacht, in Northern Germany manufacture a tried and tested solution to these problems with their trademarked KASIGLAS® Compound System. Made from polycarbonate it is as transparent as glass with
only half the weight and an impact resistance 250 times higher. KASIGLAS® offers extreme protection for those industries where mechanical stress, weather and chemical contamination can occur.
Top forest machine manufacturers, including long term partner John Deere, choose KASIGLAS® with its mar-protect abrasion resistant coating as it is:
- Scratchproof and abrasion resistant.
- Highly Flexible with the ability to absorb the impact of flying foreign objects.
- Easily adapted for different manufacturers models.
- Chain shot resistant and offers exceptionally high optical quality.
Other additional features include the invisible defrost system, smart heating system and operator glare protection with 95% light absorption.
So far, over 2,000 forest machines cabins have been fitted with KASIGLAS® mar-protect. In addition to being extremely abrasion- and impact-resistant, the 3D design means that the front windscreen and side windowpanes can be replaced with a single pane, increasing an operators field of vision considerably.
The KRD Group was established in 1968 during a period of civil unrest in Germany. At the time, the police were ‘piggy in the middle’ as they had the impossible and thankless task of protecting the state and the public. Police vehicles came under attack from rioters. Gerd Brammer, the founder of the KRD Group, experienced all of this as a technical and involved observer.
Tasks were assigned to KRD and became more diversified as creative solutions were needed and time was short. The Police vehicles required perfect “all-round protection”. Not only could the windscreen and windows shatter, but the vehicle body was also a weak point. Gerd Brammer quickly produced several means of protection:
- Puncture protection: The cavities around the body were filled to protect them against impact and puncture.
- Kasiglas: plastic composite window – The thickness of the material makes KASIGLAS® unbreakable
- A high-performance windscreen washer system, which always ensured a clear view
- The generously dimensioned safe roof escape
Gerd’s objective was to “Protect the people who protect us.”
Today KASIGLAS® is owned by the next generation of the Brammer family with two medium sized enterprises covering 25,000m², two hundred employees and an annual turnover of €23 million serving customers all over the world. KASIGLAS® endeavours to offer safety and security with perfect vision for the protection of people and goods.
Forest Machine Magazine is written and edited by a forest professional with over 40 years hands on experience. We are dedicated to keeping you informed with all the latest news, views and reviews from our industry.
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