The following article appeared in the Electric Hybrid Vehicle Technology 1999 edition. Click on the logo for additional information.
Simple Solutions to Big Problems:
Will the
EX-BIKE Save Our Cities?
O.J. Birkestrand, Rabbit Tool U.S.A.
The modern folding bicycle was invented and perfected during the 1970’s by Dr. David Hon of Taiwan. Today, more than 30 companies worldwide are producing hundreds of different models. Rabbit Tool U.S.A. did not attempt to reinvent this marvelous machine - nor do we manufacture it. All of our contributions are purposely designed to bolt on to existing designs. We think the folding bicycle is seriously underutilized as a transportation option. Our improvements are necessary to take full advantage of the folding bicycle as a practical, personal transportation vehicle. That is why Rabbit Tool U.S.A. invented the folding electric bicycle or EX-BIKE and a wheeled, collapsible hard case or T-Bag. To make our inventions accessible throughout the world, we need a little help from governments.

What Cities Must Do to Promote Bicycle Transit
To encourage EX-BIKE transportation, Rabbit Tool U.S.A. seeks the cooperation of cities and mass transit authorities. We urge you to provide public transportation passengers with three simple accommodations:
1. Provide more luggage space on trains and buses. Use airport passenger-luggage vans as the model for a simple EX-BIKE carry-on solution.
2. Make turnstile access and egress easy for EX-BIKE riders. Eliminate physical barriers with ramps, instead of stairs.
3. Dedicate lanes on some city surface streets to bicycles. Since EX-BIKES can accommodate a higher traffic density than automobiles, this can decrease congestion and improve traffic flow throughout metropolitan areas.
In central city areas of the United States, bicycle access is particularly important to economically disadvantaged residents, who are routinely and practically prevented from getting to higher-paid jobs in the suburbs because they lack convenient public transportation. All citizens could live better if they could get where they need to go quickly and cheaply, without investing in a 4,000-pound vehicle that uses a gallon of gasoline to travel only 15 to 20 miles, plus paying for the privilege of parking it. If citizens need to pedal to their destination, heart doctors agree that they will live longer and healthier.

Rabbit Tool U.S.A. Solutions
Employing modest, simple solutions, Rabbit Tool U.S.A. set out to maximize the potential of the folding electric bicycle to:
1. sharply reduce metropolitan traffic gridlock,
2. annihilate traffic-induced smog,
3. reduce consumption of increasingly scarce fossil fuels,
4. increase the general living standard and, finally,
5. improve the general physical health of bike users.
At Rabbit Tool U.S.A., we compare the transportation system of a city or country to the blood delivery system of the human body where arteries, veins and capillaries are the delivery pathways. A nation’s air, ship, rail and highway networks are analogous to the veins and arteries. EX-BIKES serve as capillaries that reach every remote nook and cranny. Just as it is impractical to have veins and arteries reach every destination in the body, it is equally inefficient to have the personal automobile serve this purpose in cities.

Of course, the EX-BIKE cannot replace the automobile, but it can be a very efficient option when combined with the “veins and arteries.” A personal automobile weighs, and uses, approximately 100 times more raw material in its manufacture than does the EX-BIKE. The personal automobile needs approximately 100 times more fuel energy to travel one mile than does the EX-BIKE. Yet, at a commuter speed of 20 miles per hour, the EX-BIKE can transport 10 times more people per hour for the same roadway width, because the high-inertia automobile requires extra space for safety. This means that one lane devoted to EX-BIKES could, in some instances, replace 10 lanes devoted to personal automobiles.

My Cadillac automobile requires approximately 150 square feet of parking space. The EX-BIKE needs less than 2.2 square feet - 70 times less space. If I live in the suburbs or a small town, parking space may not be a concern. For city dwellers living in congested high-rise apartments, owning a personal automobile is impractical and prohibitively expensive. In cities like Chicago, parking space is scarce at local commuter train stations and downtown garages, and the problem is growing worse. During the next 10 to 15 years, the population of some cities will double. We cannot double the number of highways and parking spaces in that time even if that were the best solution. Do we wish to be consumed by ever increasing concrete roadways and high-rise parking structures, or would we rather live with more green parks and open spaces?

We need new transportation solutions that make better use of our time and the Earth’s scarce natural resources - including our fossil fuels and land - lest we become entombed in concrete cities, ensnared by highways. At Rabbit Tool U.S.A., we think the EX-BIKE can serve a uniquely important role in solving transportation problems.

Bike in a T-Bag
The manual bicycle is an ingenious and highly efficient personal transportation machine used by millions of people every day in developing countries. Why has it fallen out of favor in developed countries as a transportation option? One reason is that the conventional bicycle is too big and bulky to store or ship easily inside an automobile, bus, train, or apartment. The manual folding bicycle was developed to solve this problem, which it does partly. The problem still remains that when the bike is folded, it is a jumbled collection of greasy wheels, tubes, cables, sprockets and chain weighing up to 30 pounds. Putting a bag around the bicycle helps, but does not reduce the carry weight.

To solve the weight problem, Rabbit Tool U.S.A. invented the T-Bag, which is a wheeled, collapsible hard case that makes it practical and convenient for anyone to transport and store a folding bike. T-Bag users now have quick and convenient bike transportation anywhere in the city. They can store their electric or manual folding bike in a T-Bag out of the way in a closet at home. When they go to work, they can wheel the T-Bag like luggage to the elevator and to the street. Then in 30 seconds, they can remove the bike from the T-Bag, unfold the bike, roll up the T-Bag, strap it onto the bike, and pedal to their destination. Upon arriving, in 30 seconds without tools, they can return the bike to the T-Bag, then wheel it to their work station and stow it in a closet or under a desk.

A manual folding bicycle is 3 to 5 times faster than walking, and people can be expected to ride 3 to 5 times farther than they are willing - or - able to walk. THe folding electric bicycle or EX-BIKE is even superior in this regard, because it can transport people at 15 to 20 MPH for 20 miles or longer before the standard batteries need recharging and up to 35 miles with the extra-range battery pack. When people use EX-BIKES, they are willing to ride 5 to 10 times farther to and from high-speed train or bus stations than they are willing to walk. Personal bicycles combined with mass public transportation can serve and empower both cities and citizens.
For the typical city, electric bicycles can provide extraordinary cost savings in transportation infrastructure and parking facilities. Thus, the city can serve the people’s transportation needs with far less dense grid of fixed rail and high-speed buses. This solution is workable even in such seemingly hopelessly car-dependent cities as Los Angeles. Although high-speed highways and an embryonic metro train and subway system straddle Los Angeles, the sprawling city is also a place where it is common to see 50-foot city buses carrying only a handful of riders.

Why EX-BIKE and T-Bag Solutions Are Practical
The success of Rabbit Tool U.S.A.’s system of EX-BIKES and T-Bags places high demands upon our product components. They must be lightweight, affordable, reliable and highly efficient.

Lightweight: With a steel frame, our EX-BIKE now weighs 19 Kg., or about 42lbs.
With an aluminum frame, the weight is reduced to 16 Kg. or 35 lbs.

Affordable: Reasonable cost savings comes by designing for minimum weight, the simplest and least number of parts, and high-production tooling.

Reliable: Robust reliability is achieved by proper sizing of the minimum number of simple components and eliminating threaded connections where possible.

Efficient: The unique, patented 300-Watt Electric Wheel System has a motor approaching 95% efficiency.

Modular Electric Wheel System
Designed by O.J. Birkestrand and Erland Persson, the EX-BIKE 3-phase hub motor-generator is a 300-Watt, 24-Volt Electric Wheel System. Its 4.5” diameter fits a standard 130 mm wide bike frame and weighs only 2.5 Kg. or 5.5 lbs. It is oil-cooled, brushless, sensorless and powered by NdFeB permanent magnets. This motor has a highly efficient 11:1 gear reduction, enjoys a 10:1 speed range, and a maximum efficiency of nearly 95%. The motor has an unusual 8-pole, 18-slot stator structure, chosen to minimize winding end turns, and because its intristically low torque ripple reduces noise and cogging.

Sensorless Safety Motor
The inventors elected to use a sensorless motor to minimize the number of wires exiting the motor, eliminate the axial space required within the motor for sensors, and because it is a “natural choice” for a bicycle hub installation. The sensorless motor is unique because it does not develop any torque until it reaches a certain speed. Yamaha of Japan has developed a safety system for bicycles (“PAS”) that prevents empowerment of the motor unless the operator is pedaling. Our sensorless motor basically achieves the same result without the extra pedal sensor complications. For wheelchair applications, we offer a cantilever shaft mounting version with auto-shift-series-parallel “Y” windings for high-low speed ranges. The sensorless motor is controlled by our (patent pending) simple “contactless” electronic self-centering throttle with integral regenerative braking that is smaller than the derailleur shifter it replaces. It uses a single Hall Effect device in analog fashion, actuated by our unique diametrically oriented magnetic field.

Digital Display
The motor has a single computer-controlled light that informs the operator when the motor turns on and also the battery’s charge state. The digital electronic motor controller, designed by O.J. Birkestrand and Gary Box, is fully programmable. It limits the maximum current draw and further reduces this draw when the batteries are approximately 66% deleted to allow the operator to pedal home on reduced power. We can also program the computer to sample battery temperatures providing for momentarily higher power outputs, different maximum vehicle speeds, different maximum power output, cruise control and many other functions.

Solar and Utility Rechargeable
EX-BIKES are utility rechargeable in 1 hour or less or solar rechargeable in 2 hours. Rabbit Tool U.S.A. developed a portable programmable battery charger shaped like a bike water bottle (patent pending). It can be customized to suit almost any battery chemistry or algorithm. Rated at 250-Watts, it can charge most electric bicycles in approximately 1 hour, and a wide choice of international cordsets is available. In addition, we offer a portable solar cell package for off-grid recharging, because we believe that EX-BIKES can serve a wider purpose than transportation. At remote or third-world locations, the portable solar cell recharging package can serve as an auxiliary utility to power lights, a radio, a television or a computer. To power EX-BIKES, we selected NiMH “D” and “F” cells, which we put into close-fitting, thin-walled aluminum tubes for individual cell air cooling. We use 7 Ahr Suppo “D” cells as standard and Nexcell 13 Ahr “F” cells for extended-range, high-performance applications.

Rabbit Tool U.S.A. & Birkestrand Corporation
The business of Rabbit Tool U.S.A. is to assemble and sell complete EX-BIKES and T-Bags while demonstrating and proving our technology. The business of Birkestrand Corporation is to manufacture and sell our components only to other vehicle manufacturers. If we can help you solve your big transportation problems with our simple solutions, contact us at the following address: