Designs for Land
Need for a Hand-Powered Bicycle
The handbike features a raised seat platform to ease transfers from a wheelchair. Steering, drive, and braking functions are contained in a single hand control assembly. Back-pedaling applies the brakes. Outriggers with small wheels deploy during stops and transfers. A tandem version of the handbike allows the front rider to pedal using either their legs or their hands.
Peter Axelson worked as a student advisor with Candy Minz and Doug Schwandt at Stanford University to develop a prototype. Doug Schwandt continued to refine and develop the handbike as an engineer at the Palo Alto Veteran's Affairs Rehabilitation Research and Development Center.
The handbike is currently being manufactured. Interested parties should contact Doug Schwandt.
Those interested in purchasing a handbike should consider reading the article "Purchasing Tips for Handcycles" in Active Living (May/June 1999, volume 8, issue 2). Relevant articles can also be found in adaptive sports magazines such as Sports 'N Spokes and New Mobility.
This project was funded by the Palo Alto Veterans Affairs Rehabilitation Research and Development Center and Beneficial Designs, Inc.
For more information about handbikes, contact PVA Publications.
Off-Road Wheelchair Seating
Need for Off-Road Wheelchair Seating
Up and Over Engineering has made mountain bike technology available to the wheelchair rider with the Cobra Off-Road Wheelchair. The four-wheel disc brakes, knobby mountain bike tires, and directional steering enable wheelchair users to enjoy the rugged ride offered by back-country trails. The Cobra is easier to ride when the user's center of mass is as far back and low as possible when going downhill, and as high and far forward as possible when going uphill. A mechanism that adjusts the rider's center of gravity to an optimal position without fundamentally modifying the wheelchair frame was needed.
A lightweight frame structured to support the seating was fabricated and installed onto the Cobra frame with reinforced Kydex linkages. This minimal modification allows the seating system to swing up and forward in the wheelchair using a four-bar linkage.
Up and Over Engineering
5927 Monte Verde Drive
Santa Rosa, CA 95409
This project was sponsored by Beneficial Designs, Inc. and Up and Over Engineering.
Dynamic Seating Orthosis
Need for a Dynamic Seating Aid
People with spinal cord injuries often do not have the back musculature control to sit up after leaning forward in their adaptive equipment. Cross country skiers, mono-skiers, and wheelchair road racers in particular need to lean forward and then sit up a moment later while moving forward with speed.
Many such athletes have enough strength in their abdominal musculature to pull themselves forward against a counteracting spring force. This spring force can be used to help them return to an upright sitting position. A dynamic seating orthosis that supports the user in an upright position was designed to take advantage of this ability.
Many adaptive recreational devices use custom molded orthotic seats that fit the user like a well-fitted boot. Early seating orthosis prototypes consisted of a molded plastic seat that rose from the buttocks to the upper torso. Flex points at the back were added to give the user more freedom of movement.
In a radical departure from this approach, the seating system was divided into two sections. The lower section consists of a seat shell that comes up to the L1 level of the athlete. The upper section grips the user from approximately T10 to T5 and is custom molded to fit the individual. One or two flexible fiberglass rods link the upper and lower sections. These rods are clamped to the lower seat shell at the back of the user and extend up into a plastic tube mounted to the back of the upper section. When the athlete leans forward, the fiberglass spring rods bend forward and slide through the upper support. Varying the thickness and flexibility of the spring rod varies the degree and direction of torso movement.
Three configurations of the upper block system have been tested: one that allows only forward and backward movement, one that allows rotation of the upper body, and one that allows lateral flexion of the spine. The system was tested by Peter Axelson in his mono-ski while he was a member of the U.S. Disabled Ski Team.
This project was funded by Beneficial Designs, Inc. and Allen Siekman, Children's Hospital at Stanford.
Piano Pedal Pusher
Need for a Piano Pedal Pusher
Musicians with lower extremity limitations are unable to utilize the floor pedals on standard upright or grand pianos. While electronic pianos and synthesizers give many people the flexibility and control they need to play keyboards, many individuals would still like to be able to control the sustain mechanism on an upright or grand piano. An appropriate device would allow pianists to pedal without interfering with head or body movements or the ability to sing.
Developing a Functional Prototype
An electric grand piano was made available by Yamaha to develop a prototype system. The high spring force resistance of the pedal was reduced by removing an internal piano spring. It was found that pedal movements tilt an actuator rod inside the piano that activates the sustain mechanism. The pedal interface was deemed unnecessary and removed.
A pneumatically operated actuator rod was developed to replace the pedal interface. An air bladder was threaded through a money belt worn around the waist. Abdominal muscle movement compresses the air bladder, which in turn pressurizes a simple plastic air bellows. The air bellows pushes a vertical connection rod upward inside the piano. This impacts the piano's original sustain actuator rod and initiates the sustain mechanism.
An exploded parts diagram is illustrated here to enable others to fabricate the piano pedal pusher from locally available parts and components. A "do it yourself" article was published in a RESNA Newsletter.
This project was sponsored by Yamaha America, Inc. and Beneficial Designs, Inc.
Manual Transmission Hand Controls
Need for Manual Transmission Hand Controls
Individuals with paraplegia desire to operate manual transmission vehicles for a variety of reasons. People enjoy driving manual transmission vehicles to experience the challenge and thrill of driving a sports car and to exercise better control over engine power output. In addition, manual transmission vehicles are typically more economical to purchase and operate than vehicles with automatic transmissions, power brakes and power steering.
To create a set of hand controls that could be operated with one hand and fitted to an automobile with manual transmission, brakes, and steering, a motorcycle throttle was added to a set of existing automatic transmission hand controls.
The motorcycle throttle is mounted to the left of the steering wheel. A push towards the floor applies the brakes, a clockwise twist engages the clutch, and a counterclockwise twist depresses the accelerator.
To change gears, the driver holds the steering wheel in position with the thumb of the left hand while shifting with the right. When stopped on a hill, the driver can let out the clutch, apply gas, and release the brakes simultaneously with one hand. A driver using these controls must have good coordination, dexterity, and strong muscles with precise control.
The system is connected to the clutch, brake, and accelerator floor pedals with mechanical linkages. Since the hand controls are only hooked to the floor pedals, and do not replace them, non-disabled drivers can operate the same vehicle using their feet on the pedals.
This work was sponsored by Beneficial Designs, Inc.
Based on the early work by Beneficial Designs, a group of students created a custom set of hand controls and disclosed their work in the following report:
Brandley Dallan; Breigenzer, Kurt & Siers, Dennis. "Adaptive Driving Controls for Standard Transmission Vehicle." Montana State University, 1990.
Obtaining Hand Controls