1978 - Volume #2, Issue #6, Page #03[ Sample Stories From This Issue | List of All Stories In This Issue | Print this story | Read this issue]
Slick Way To Unstuck Cars, Trucks Or Tractors
Until we saw it demonstrated, we didn't really believe anything so simple could be so effective. "It may look simple but you won't believe all the time and money it took to get the idea perfected," inventor Tod Granryd, told FARM SHOW.
A consulting agricultural engineer by profession, he is also president of TG Strips, a new company he founded to manufacture and market his patented new invention for "unstucking" virtually any four wheel vehicle - car, truck, tractor, camper, van, bus or whatever.
Sets of TG Strips designed for "unstucking" passenger cars, pickups, campers and vans are already in production. Heavier duty models for freeing tractors, trucks or possibly combines from mud or snow will be available in early 1978, reports Granryd.
Here's how the system works in "unstucking" a passenger car:
Everything you need to move it out of a deep mud hole or snow bank comes in a small 8 by 10 box, weighs only 101bs., and has no moving parts. It consists of:
1. A pair of anchoring-traction strips (one for each side of the car). Each strip (see photos) is made up of a 4 ft. long anchoring mat at one end and a 3 ft. long traction mat at the other. These two mats have deep corrugations on one side for traction and are securely connected to each other with seat belt type webbing. A heavy duty buckle allows distance between the mats to be adjusted, as needed, to fit wheel bases from 85 to 125 in.
2. Also in the box is a winch assembly made up of two short straps (one for each rear wheel) and two short pieces of hose (which makes for easy unbuckling when the job is done). These "winch assembly" pieces are needed only if the car is really buried in mud or snow. In most cases, the strips alone will be sufficient to free the vehicle, Granryd points out. Here are the steps to follow in "unstucking" a car or pickup with rear-wheel drive:
1. Roll out the strip along the vehicle (one on each side).
2. Lay the anchoring mat portion of it in front of the front "nondriving" tire, with corrugations toward the ground.
3. Lay the traction mat portion of it in front of the rear tire, withi the corrugations toward the tire.
4. Repeat for the opposite side of the vehicle.
"In mast cases, that's all that's required to get going and it takes but a few minutes," Granryd points out. "Each strip creates its own fixed point by means of the anchoring mat placed ahead of the front non-driving wheel. It stays put, thanks to the weight exerted upon it by the car, and to a special shoe which is molded right into the mat itself. The heavy corrugations are built in to provide the highest possible coefficient of friction."
Granryd spent a lot of time and money searching for a strong, lightweight and durable coupling between the two mats that wouldn't rust, and that wouldn't rip or break. He gave up on the invention twice, unable to find a fabric strong enough. He finally hit on the idea of using ordinary seat belt webbing. It has a minimum breaking strength of 5,000 lbs., is light weight and also abrasion resistant. In manufacturing the strips, this strong seat belt webbing is used from one end to the other of each strip assembly and is molded right into the front and rear wheel mats to form a super bond, explains Granryd.
Once he had the strips perfected, he discovered that there can be times when they alone wouldn't do the job if the vehicle was severely mirred down in mud or snow. "There is a limit to the coefficient of friction that can be obtained between two free surfaces - even crawler tractors, for example, will spin their tracks at times," he points out.
To eliminate this limitation, Granryd hit on the idea of a simple winching kit, which consists of a short strap and a short piece of hose for each rear wheel: "The straps tie the traction mats to the rear driving wheels, making them function as two powerful winches. You simply put the transmission in gear and step on the throttle. As you roll out a
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