Apr 9 2008
It is a fact that flat tires hinder movement. All gardeners, handymen and construction site workers who have tried pushing a heavily laden wheelbarrow with an under-inflated tire know this only too well.
It takes a lot more effort to move them and they are more difficult to steer. The same applies to wheelchairs, mountain bikes, trolleys and any other wheeled vehicles. All sorts of hazards also threaten the tires, such as nails, shards, broken glass, etc. If a wheelbarrow hasn't been in use for a while, e.g. during winter, the first user will often be in for a nasty surprise in the shape of a flat tire. The British company Greentyre in Middlesborough has paid heed to the exasperated sighs of gardeners the world over and designed tires that aren't affected by sharp objects or long periods of inactivity. The tires are made of a micro-cellular polyurethane foam based on a BayflexR system from Bayer MaterialScience. "Products made of this innovative material are longer-lasting and much lighter than solid rubber tires," says Colin Scarsi, Managing Director of Greentyre. "They are essential for anyone who wants a vehicle that is ready for operation at all times."
The company has developed and patented an ingenious technology for the production of these tires. BaySystemsR, the worldwide partner for polyurethane system solutions from Bayer MaterialScience, provides a tailor-made polyurethane system for this special production process. To manufacture the tires, the mold is filled with a liquid reaction mix before being rotated during the foaming process. This ensures that the material is distributed very evenly across the whole tire circumference, which means that the tires will run very smoothly. "The rotation method also creates a special integral skin foam structure in which the density of the foam increases towards the outside of the tire," explains Daniel Seidlitz, an expert in polyurethane foam systems at Bayer MaterialScience. "The material is virtually solid at the tire's outer circumference, and its even surface makes for excellent rolling properties." Thanks to the tire's good aging and weathering resistance, it retains its true-running properties in the long term, even when it remains in one position under a heavy load for an extended period of time and becomes compressed on one side. And the high elasticity of the micro-cellular BayflexR material ensures that the tire's rolling resistance is almost as good as that of an air-filled tire.
High-quality wheelbarrow tires marketed around the world under the name GreentyreR, are in great demand. That's why the well-known British DIY chain B&Q recently added the tires to its range. And for anyone who enjoys gardening as a hobby, tires and wheelbarrows from Funky BarrowsR are now also available in a range of vibrant colors.
However, this tire technology is not just useful for leisure activities and gardening - it is also ideal for wheelchairs. Under the brand name Greencare MobilityR, the Greentyre company has designed a very special wheelchair for disabled people. One key feature of the sophisticated design concept is its modular structure, which enables users to choose from an array of options to meet individual clinical need and, of course, a range of GreentyreR tires depending on the type of use. If required, the wheels can also be removed at the touch of a button. Additionally, the wheels of Greencare MobilityR wheelchairs are equipped with ergonomic handrims also made of polyurethane.
The special feature of these handrims is that they do not get sharp edges through wear and are pleasantly warm to the touch. And last but not least, the wheelchairs' adjustable arm rests are also padded with this polyurethane foam and available with safety lamps as an option - another first from the innovative Greentyre company. It seems that the versatility of this elastomeric cellular material knows no bounds.
Posted April 9th,2008