Solenoids

The authors would like to thank the following people for their dedication, generosity, and support which greatly

contributed to the success of this project.•Chris Roush – Marshall Music Co.

•Greg Ritchey – Magnet-Schultz of America•Rich Yarch – MSU Upholstery Shop

•Dr. Robert Hubbard•Mr. Timothy Hinds – Project Advisor

Reverend Richard Moe was born with spinal muscular atrophy (SMA), a progressive & degenerative muscle condition. With the recent loss of the strength in his fingers, he was unable to effectively operate the valves on his tuba. The scope of this project was to develop an assistive valve actuation system that would allow Mr. Moe to continue to play his instrument with minimal strength. Additionally, a support system was necessary; this would bear the weight of the tuba while also raising the height of the mouthpiece to promote beneficial posture.

Valve Actuation System: -ActuatorsLinear solenoids provided the force and displacement to operate the instrument valves.

Assistive Actuation of Brass Instrument ValvesRaymond Gallagher, Daniel Isaac, Zachary Kaltz, Matthew Ryerkerk

Instrument Support System:

A contoured cushion was chosen as the support system. Rubber grip fabric on the bottom prevents the instrument from sliding off the seat. The straps attach the cushion to the tuba and can compress the cushion for an adjustable height.

Valve Actuation System:

It was required that the solenoids have a holding force of at least 1.2 lbs (5.3 N), a maximum response time of 0.3 seconds, and a stroke distance of 1inch (2.54 cm). Further, a 100% duty cycle was required. The final design was determined to have a response time of approximately 0.2 seconds for each of the valves. It was calculated that a .625 Amp current at 24 Volts was needed to operate the device.

Spacing of the solenoids was an important factor in the modeling of the device. The valves on the tuba were 0.5 inches apart.

Instrument Support System:

The instrument support pad was modeled to fit in between the legs of Mr. Moe and rest on the seat of the wheelchair. A cutout in the center of the pad was made in and straps were added to ensure secure attachment to the tuba.

2.56 inches

0.75 inches

1 inch1

2

3

1 inch

1 inch

Figure 1. Linear solenoids (R24X30 Magnet-Schultz)

Figure 5 (a). Valve spacing as seen on actual instrument

Figure 5 (b). Valve in open and closed positions with a 1 inch stroke distance

Valves

Springs

Valves

Additional work optimizing the size and weight of the device is needed in order obtain the most robust product. Additionally, the performance of the device can be optimized by developing a custom made solenoid design specifically for the required force and stroke distance required. The valve actuation system developed should not be restricted use only with the tuba. Additional work is necessary in order to modify the device so as to make it compatible with an instrument being played.

Pushing force = 1.2 lbs

Restoring force of spring

Valve Open Valve Closed

AcrylicBolts

Figure 3. The mounted actuation system has an adjustable control box.

Acknowledgements

III - ModelingI - Introduction

II - Design

IV – Future Considerations

Figure 4. The solenoids (D=1.5 inches) were modeled in Unigraphics as per the dimensions specified by

the manufacturer

ValvesFigure 2. Three solenoids were mounted to acrylic plates.

-Control BoxLow-resistance switches independently controlled the solenoids. Velcro on the control box and mounting allowed adjustable positioning for user comfort.

-MountingAcrylic plates with foam are bolted to each other to hold the solenoids above the valves.

Figure 4. The support cushion attaches to the bottom of the tuba.