Mechanized Legless “Classic Rocker” Team #7 Tom Dabrowski Sarah Philo Adam Rauwerdink

Outline Specifications Physical challenges Mechanics of rocking Potential mechanisms Competitor products Project constraints Design summary Budget Marketing Conclusion

Specifications  Rocking mechanism  Comfortable speed  Does not surpass tipping angle (varying user weight)  Does not require permanent attachment to floor  Control  Simple power switch for user  Control of audio by user  Caretaker has master control for all power and for music track and volume  All easily accessible and with high ease of use  Audio  Internal speakers  Input from CD player accessible to caretaker

Physical Challenges  Users have wide array of physical and mental limitations  Cerebral palsy, Multiple sclerosis, varying levels of paralysis  Coordination  Muscle control  Mental abilities and attentiveness  Seizures of varying intensity (some CP)

Mechanics of Rocking  Equilibrium, all in line  Center of curvature of rocker  Center of gravity of chair and occupant  Point of contact with ground  No moment

Mechanics of Rocking (con’d)  Chair rotated  Restoring moment from force of gravity  Moment taken about point of contact with ground M=Iα Moment = (Moment of Inertia) x (Angular Acceleration) -mg(R-h)sin(θ)=mh 2 α  Frequency of rocking  Dependent on radius of curvature and occupant center of gravity

Mechanics of Rocking (cond’d)

Potential Mechanisms  Rack-and-pinion styled  Motor turns stationary small gear over a long, linear piece attached to chair back  Counterweights  Like an elevator system  Linear Actuator  Rod extends, pushes up on chair back  Rod returns, pulls down chair back

Competitor Products/Previous Projects Electronic and Mechanical Assistant Technologies – Motorized Rocking Chair NSF Project – Rensselaer Polytechnic Institute – 1989 – “The Mechanical Rocking System”

Various non-mechanized legless rockers, available at many major retailers (Wal- Mart, Target, etc) Numerous patents granted for mechanized rocking systems Single instances (web forums) Competitor Products/Previous Projects (con’d)

Project Constraints  Safety  If 120V power is being used, must be completely isolated from possible shock and from chair fabric  Angle and speed of rocking must not cause tipping  Environmental  Must be durable and capable of surviving moderate abuse  Should be able to withstand spilling of liquids and be easily cleaned  Economic  Pre-built chair must be purchased

Project Constraints (con’d)  Control  Caretaker must be capable of having master control of the rocking  Audio volume, track, and master power are also to be under caretaker control  Construction  Internal frame of chair will vary with models  Ability to build off of frame will be dependent on this

Design Summary

Budget  $750 from National Science Foundation  Chair prices ($30-$100)  Quality (frame, fabric)  Accessories (speakers, audio input)  Motor ($16-$50)  Power, RPM  Actuator ($100-$150)  Power, length  Speakers ($40-$100’s)  Wattage, size, quality  Accessories  Amplifier ($100+) – probably excessive  Subwoofer  Linkage bars, brackets, mounts  Frame material  Maximum Total: $500 (rest for error analysis)

Marketing  Target: special needs consumers who wish to enjoy a relaxing experience  No physical input needed to rock  Music enhances overall experience “Classic-Rocker”  Simplicity  Basic controls  Simple controls for caretakers

Conclusion  Will provide self-rocking motion for those with physical disabilities  Reliable, easy to use, and safe rocking mechanism  Final product will include implanted audio system to enhance the “experience”  Caretaker will have master control over all parts of the chair  Complete product will be sturdy self-contained unit that is easy to maneuver