EZ-Jam

grabcad

I am currently a student at The University of Alabama in Huntsville and I designed the EZ-Jam, a guitar attachment that makes it easier to play guitar chords. Guitars are one of the most commonly played instruments; however, many people are unable to play them due to large fingers, hand injuries, or arthritis. The EZ-Jam is designed to allow users with these symptoms to still play the guitar. The EZ-Jam is also a quick way to learn how to play the guitar for those interested in just learning a few chords.For people with arthritis, typically pain is felt most when their fingers are curled over tightly and in order to play the guitar, the player’s hand must be able to curl around and press the strings firmly against the fret board of the guitar. Therefore, it can be very painful if not impossible to play the guitar.Current guitar chord attachments help users typically play around four chords but still require the user’s hand to curl completely around the guitar’s neck and press on the fret-board. In contrast, the EZ-Jam allows users to play nine chords and does not require the user to curl their hand completely around the guitar’s neck. The chords offered by the EZ-Jam are some of the most commonly used guitar chords: G, D, Dm, E, Em, A, Am, F, and C. The minor chords are denoted as D’, E’, and A’ on the EZ-Jam in order to fit within the available space.To use the EZ-Jam, the user simply slides the chord selector (white component in the pictures) to the desired chord, which is shown on the base (red component). Once the chord selector is in position, the users just has to press down on the chord selector and the EZ-Jam is ready to play the chosen chord. To switch to a different chord, the user simply releases pressure on the chord selector and another chord can be selected by sliding the chord selector up or down the guitar’s neck. When playing a chord, the chord selector remains offset from the guitar’s neck such that the user's hand maintains a wide grip on the guitar’s neck, rather than a tight curl that induces arthritic pain (see picture). The chord selector also eliminates the need to individually finger the guitar strings, which helps players with large fingers or finger injuries to still play.The EZ-Jam is 3D printed in three unique pieces, the chord selector (white), the removable springs (blue), and base (red). All of the pieces, including the four required springs, can be printed within the required bounds of 120.65 x 120.65 x 120.65 mm (see picture). The base of the EZ-Jam contains 18 small spring arms which are responsible for pressing on the guitar strings. The base component is also designed to be secured to the guitar neck via rubber bands. The chord selector is used to form each of the nine possible chords. Each guitar chord requires several strings to be pressed at the same time and to do that, the bottom of the chord selector contains a compact pattern that combines the chord-structure of the nine chords. This pattern, when aligned correctly, pushes down on only the spring arms needed to form the chosen chord. For a visual representation of the chord selector’s unique pattern and how it forms the nine chords, please see the chord mapping video. The removable springs are connected to the chord selector and are used to return the chord selector to the upright position after being pressed down. Since the springs fatigue over time, they are printed as separate parts and have a quick attachment point that makes it easy to quickly replace them.The EZ-Jam was printed out of ABS plastic using a MakerGear M2 printer (single extruder FDM printer with detachable support). ABS plastic was chosen for the project since, when printed thin, could be used to create springs that would endure extensive use. ABS also offered enough strength that it could form the structural components of the design. As previously mentioned, the base component contained 18 small springs that were printed directly into in; therefore, the material chosen had to be able to be both strong and flexible. Being able to 3D print the small springs directly into the base component of the EZ-Jam is an advantage 3D printing offers over traditional manufacturing methods. Creating integrated springs helped reduce the size of the EZ-Jam as well as simplify the assembly of the project. The flexibility of ABS also made it possible to assemble the EZ-Jam without any fasteners. Prior to being attached to the guitar, the base component is quite flexible and this allows it to bend open wide enough for chord selector to be inserted into it (see picture).3D printing the springs for the EZ-Jam required considering the build orientation of the parts. The EZ-Jam contained two spring types, the large removable spring and the small spring arms. The spring arms were printed in the horizontal (XY) plane, such that the spring would be made of several wide horizontal layers and would flex along the YZ plane (see picture). The spring is only 1 millimeter thick, which allows it to remain flexible and its build orientation, keeps the springs’ printed layers from delaminating or cracking. Similar to the spring arms, the large removable springs were also printed in the horizontal (XY) plane; however, unlike the springs arms they designed to flex along the horizontal (XY) plane. In order to flex along the XY plane, the springs were printed such that they did not have any infill, rather were completely printed out of perimeters (see picture). The perimeters allow the springs to flex rather than snap since the direction of the perimeters flex long the direction of the spring’s deflection. For more information, please see the following videos of the EZ-Jam:Demo Video: https://youtu.be/nQcLvhQrVTAChord Mapping Video: https://youtu.be/BgsTLJTF8Go