Door Mounted Guitar Display Fixture

Transcription

1 Door Mounted Guitar Display Fixture

2 Transmittal Letter MECH 690 Senior Design Summer 2010 Mr. Peter Rourke Mr. Richard Roberts Associate Professor Department of Electronics and Mechanical Wentworth Institute of Technology 550 Huntington Avenue Boston, MA Professor Rourke/Roberts, Our formal report regarding the Door-Mounted Guitar Display Fixture is enclosed. The report focuses on the construction and deconstruction of the prototype door mounted guitar fixture that was uniquely designed to stand out from any current guitar fixtures. Data was collected from the leading guitar and bass guitar models, providing dimensional parameters for the design. Kinematic issues regarding pulley ratios, translation of linear to rotational movement, and drive belt tensile forces were addressed and calculated in order to build an automatic mechanism for the fixture. SolidWorks finite element analysis testing on the key stress components were performed, in order to ensure a reliable design that is able to withstand any forces introduced either by the wall or the guitar. Through individual and assembly studies, crucial values were determined, thus providing useful data for proper material selection and geometries for the fixture s components. As this prototype was subjected to various forces from all directions such as guitar weight, door slams and hanging force; 6061 aluminum was chosen for prototype fabrication. Through Field testing and numerous guitar hangings our expected results confirm that the Door- Mounted Guitar Display Fixture meet and exceeds all objectives, while designing a practical and functional fixture. The resulting dimensions and FEA analysis prove that the fixture is a reliable solution that meets the design goals that we set for it, in addition to overcoming problematic issues seen in existing guitar displays. We look forward to your review. Sincerely, Eric DuComb Derek Iredale Matt Bury 2 P age

3 Door-Mounted Guitar Display Fixture Group 2 Submitted to Professor Richard L. Roberts Professor Peter Rourke June 11, 2010 By Eric D. DuComb Derek Iredale Matthew Bury Wentworth Institute of Technology MECH 690 (DuComb) ducombe@wit.edu 1012 High St Palmer MA (Iredale) iredaled@wit.edu 22 Sunset Terrace Merrimac, MA (Bury) burym@wit.edu Dartmouth, MA For additional information, pictures, and video please visit our website at 3 P age

4 Abstract: The following project reveals the groups design process in developing a Door-Mounted Guitar Fixture. Design goals include making the device lightweight, affordable, and able to safely secure the most popular guitar/bass instruments on the market today without damaging either the guitar or the interior space. Objectively, this project was aimed to eliminate all the faults in existing guitar displays and to bring together all of their positive attributes in a new unique way that has never been done before. As a solution to this problem the group chose to use an interior door to safely mount and display an electric guitar. The group first quantified the average dimensions and weights of common guitar models on the market in order to get a general idea of what they would be designing for. Multiple concept sketches involving different methods of fixing and protecting the guitar were developed. These designs were then put into a design matrix to evaluate the effectiveness of each design. Once a design was chosen, theoretical hand calculations and an FEA analysis were done on this design to determine the kinematic motion and loading method of securing the guitar. As the design progressed, different ideas from past concepts were revisited and evaluated to incorporate and add to our working design. Once the design was deemed reliable, the group chose appropriate materials to fit design specifications and then created a working model of the Door- Mounted Guitar Fixture in SolidWorks. The SolidWorks model was worked on in conjunction with the fabricating of the prototype to help create the best design possible in terms of manufacturability, while maintaining a well structured, operating fixture. 4 P age

5 Table of Contents: Transmittal Letter..... Page 2 Report Cover Page 3 Abstract.. Page 4 Introduction... Page 6 Existing Designs Page 7 Collected Data Page 9 Design Matrices. Page 10 Basic Design Overview Page 11 Sample Calculations.. Page 12 Results Page 15 Discussion of Results Page 17 Conclusion Page 18 Future Projections. Page 19 References. Page 20 Appendix I: Concept Sketches.. Page 21 Appendix II: Model Distance Measurements Page 23 Appendix III: FEA Plots Page 25 Appendix IV: Official Part Drawings Page 31 Appendix V: Work Plan.. Page 46 Appendix VI: Professional Resumes.. Page 47 5 P age

6 Introduction: Breaking of musical instruments during a rock performance has been a spectacle for concert audiences to behold for many years. Unfortunately, this action can be a lot less spectacular when it happens offstage at casual guitar player s home, due to an accidental bump that caused the guitar and it s stand to make hard contact with the floor. Customers searching for the appropriate guitar display for their homes have a very limited amount of options with the currently available products. Furthermore, each known product has certain drawbacks or flaws that leave room for accidents to occur. It is for these reasons that the group has designed/created a design that will offer more options to customers seeking to purchase a display fixture for their guitar. The following document demonstrates the plan to create a Door-Mounted Guitar Display Fixture that will allow users to safely mount their guitar behind any interior door. The following sections will describe, in depth, how the group went about researching, designing, testing, developing and fabricating this system in a logical manner. 6 P age

7 Existing Designs: When it comes to guitar displays there are currently a few popular designs for musicians to choose from. The first design is a tripod floor stand. This tripod floor stand (also known as GS-1) consists of three legs at a low pitch that support a vertical member. This vertical member holds the guitar with two U-shaped hooks. The hook at the top of the hangar supports the neck of the guitar, making contact with the midsection of the guitar s neck. The second U-shaped hook supports most of the load by holding the guitar at the bottom of its body. The pitch created by these two hooks causes the guitar to lean backwards slightly. These hooks are lined with a soft rubber sleeve to protect the guitars surface from damage and to keep the guitar on the hooks with a high coefficient of friction. The wall mount utilizes similar U-hooks like the tripod floor stand but in a very different way. Instead of using two hooks to secure the guitar at the bottom of the base and the neck, the wall mount uses one hook to bear the load of the guitar just below the headstock. This hook is a lot thicker than the hooks used in the tripod floor stand, as it must support a heavy bending load. This hook it attached to a wood or metal base that is fixed to the wall with 2-4 (depending on the brand) wood screws. 7 P age

8 The last commonly found guitar stand is the A-frame guitar stand. This guitar stand is a folding floor stand in the shape of an A. It has sturdy rubber grips to prevent sliding on the ground. This stand is able to hold many different types of guitars with it s uniquely bent velveteen rubber base holders. When designing something that is meant to be low in weight and cost and high in strength, it is important to look at the strength to weight ratio of materials, also known as specific strength. Generally, Ceramics, Composites, and certain Metals and alloys offer the best specific strength. Many of the ceramics with good specific strength are either too expensive or too brittle for the purposes of this project. Composites such as carbon-fiber reinforced polymer (CFRP) and glass-fiber reinforced polymer offer amazing specific strength and have a little more ductility in comparison to the ceramics. As far as metals go, high alloy steels, titanium, and aluminum are undoubtedly some of the best when it comes to specific strength. For the needs of this project, the group will be taking a more in depth look at certain composite materials and alloys when designing the structural frame of the guitar display. It would be near impossible and very inefficient to design a display fixture that accommodated every known guitar model being sold today. It was discovered that the maximum weight guitar for the popular models was around 13 pounds. The group rounded this number up and decided to design for 15lbs before any safety factors. In order to design this product to get the most use, the needs of the display fixture must meet the requirements set forth by the most widely sold models in the US. Research shows that the two leading competitors in guitar sales are companies, Fender and Gibson. Based on sales, Fender sells more guitars every year than any other leading guitar manufacturer. The Stratocaster, Telecaster, Precision Bass, and Jazz Bass models make up most of these sales. Gibson s top selling models include the ES-175, ES-335, Flying V, Explorer, Firebird, SGs and Les Paul. Other brands, such as Schecter, Ibanez, Yamaha, and Jackson also make up a large percentage of guitar sales in the US. Many of these electric guitar models have the same features in terms of body thickness, average length, and width at the headstock. Designing the fixture to accommodate the majority of the guitar models being sold by this company, within reasonably similar dimensions, would yield the greatest benefit to the overall usefulness in the design of the product. 8 P age

9 Collected Data: Current Guitar Measurements Model Length Thickness Neck Width Body Width (in) (in) (in) (in) Telecaster /4 1 5/8 13 Stratocaster /4 1 5/8 13 Firebird 35 1/4 1 1/2 1 11/ Les Paul 32 15/16 2 1/4 1 11/16 13 SG 33 5/16 1 3/4 1 3/4 13 Ibanez GRX 31 1/ /16 1 3/ Ibanez ART /4 1 3/4 16 Epiphone Dot 35 1/4 2 1/4 1 11/16 16 Emperor Swinger 34 3/4 3 1/8 1 3/4 14 Jazz Bass 37 1/2 2 1/8 1 1/2 13 P Bass /8 1 3/4 13 Thunderbird /4 1 3/ Yamaha RBX / EPB epiphone 34 5/8 2 1/4 1 1/2 13 Max Dimensions Min Dimensions P age

10 Design Matrices: In determining the design for the guitar door fixture, design matrices were constructed in order to find the rite design. The designs were weighed with a rating from 1-5, with 1 having the lowest value and 5 having the highest. The six categories which were focused on to figure out which design would work includes: effectiveness, cost, manufacturability, assembly, adjustable and protection. The effectiveness incorporates how well the design will hold the guitar and how practical it is, will it function correctly. We decided to have our design be easily adjustable to a number of different size guitars, as well as being cost effective in terms of the materials need. Protection was an important category because one of our objectives is to safely protect the guitar from movement from the door swinging open and close. We also rated our designs on the ability to manufacture and assemble the designs. How well the fixture work and can it be easily assembled. The design matrix proved that design D would be the best choice to pursue. However, once the designs were developed further, it was revealed that design A actually be more cost effective and lightweight. In the end, the group decided that it was worth choosing design A to pursue for their prototype. Designs Effectiveness Cost Manufacturability Assembly Adjustable Protection Design A Design B Design C Design D Design E Total Table 2: A matrix of our design concepts Current Designs Effectiveness Cost Manufacturability Adjustable Protection Portable Tripod A-frame Wall Mount Hercules Stand Total Table 3: Matrix of Current Guitar Holder Designs 10 P age

11 Basic Design Overview: The final design chosen by the group demonstrates a simple, yet efficient way of automatically securing the guitar. First and foremost, a piece of sheet 0.1 thick sheet metal is shaped to contour to the top of a door. The rest of the assembly is bolted to this piece of sheet metal. The actual guitar hangar in this fixture is much like the hangar seen in the wall mounted fixtures, with the exception that this hangar is mounted to a guide block located on the inside of a hollow square tube spine. Encased in this spine is a connecting rod that connects the top and bottom guide blocks together so that they move linearly and proportionally to one another. Channels were milled at the top of the front face of the tube to dictate the appropriate amount of linear movement to allow for a ninety degree rotation of the arms located further down on the fixture. In order to translate this linear motion to a rotational motion, a gear and rack were placed at the bottom of the. The gear was connected to a center pulley that was used to drive the side pulleys from the open position, when no additional weight was placed on the hangar, to the closed position when a guitar was placed on the hangar. The open and closed operating states of the fixture were achieved by the placement of a spring on the top surface of the top guiding block that would effectively reset the fixture when no weight was place on the fixture. Opened State Closed State 11 P age

12 Sample Calculations: -Pulley Relations D Pulley A =3 θ rev A =1/4 rev D Pulley B =1 θ rev B =3/4 rev -Rotational to Linear Motion θ rev B =3/4 rev D gear pitch =Diametral Gear Pitch=0.750 x traveled =travel length along rack= P age

13 -Spring Conditions F guitar =minimum guitar weight = 5lb x traveled =travel length along gear rack=1.767 k=spring constant = 3 lb/in F preload =estimated resting gravitational force of internal components=5lb k=spring constant = 3 lb/in x preload =length to preload spring fixture to= P age

14 -Tensile Force in Belt 2 4 δ=change in length 11 E=Tensile Modulus of EPDM rubber=172.5 psi D=Diameter of Round belt =0.250 L=Original Belt Length = 15 F=Tensile Force in Belt=12.42lb Common Calculations- σ=tensile stress (psi) F=force (lb) A=Cross Sectional Area (in 2 ) FoS=Factor of Safety σ yield =yield strength (psi) σ max =maximum strength (psi) 14 P age

15 Results: -Dimensional Results (Plots Located in Appendix II) Measurement (in) Allowable Guitar Width 15.5 Allowable Guitar Thickness 3 Allowable Neck Thickness 2.5 Allowable Guitar Length any -FEA Results Summary (Plots Located in Appendix III) Part Material Applied Load (lb) Max Stress (psi) Yield Stress (psi) Max Displacement (in) FoS Pass or Fail? Guitar Hangar AISI Pass Door Mount 3003 H X Fail Door Mount AISI Pass Cross 6061 Bar Aluminum X Pass Arm 6061 Aluminum Fail Arm 6061 T6 Aluminum Pass Alloy Belt EPDM Rubber X Pass -Weight of fixture SolidWorks Mass Measurement = 9.54 lb Physical Prototype Measurement = lb 15 P age

16 -Prototype Cost 2"x2"x36" Aluminum Tube /8" Square x 3" Guide Blocks " Pulley Stock 9.57 Spur Gear Spur Gear Rack 1.55 Sheet metal mount 30.7 Standard Hangar Connecting Rod x Pulley Belts Spring 1.62 Aluminum Arms Misc. Hardware 10 Total P age

17 Discussion of Results: By analyzing the some of the key stress points in the design, the group was able to take necessary action by changing the geometry or the material of the component in order to achieve a reasonable factor of safety. A factor of safety close to 2 was the desired goal for the components in question. When the component failed testing, the group changed the material to increase the yield strength of the component, thus increasing the safety factor. Our original material selections for the door mount and the arms of the fixture came out to have very low safety factors. Necessary steps were taken to choose stronger materials without driving up the cost or the weight of components in the fixture. Changing the door mount to a low carbon steel such as AISI 1020 and tempering the 6061 aluminum to 6061-T6 proved to be the right steps to take to ensure the reliability of the fixture. Ethylene propylene diene monomer (EPDM) rubber was a good choice for creating the driving belts of the fixture. This rubber, being formed into a round belt with a diameter of one-quarter of an inch and stretched along the pulleys, allowed a tensile force of twelve pounds to keep the pulleys moving in proper relations to one another. Furthermore, for this application, the rubber belt is nowhere near reaching its tensile limit. 17 P age

18 Conclusion: In conclusion, the group s final prototype was considered a success. The FEA analysis on the guitar hangar proves that the design is capable of holding any guitar up to a weight of fifteen pounds. By keeping tight dimensions in the arm design of the fixture, the group was able to restrict any movement of the guitar once mounted on the back of a door that is opening and closing. Additionally, these dimensions allow this design to be used by almost any popular electric guitar model currently being sold. The analysis done on the crossbar and the arms of the fixture prove that the fixture is capable of withstanding a force of thirty pounds to the arms without causing any components to go beyond their yield strengths, causing permanent deformation. By mounting the fixture over the top of a door, this fixture succeeds in elevating the guitar off the ground and eliminating any risks involved while displaying a guitar on one s floor. The weight of the SolidWorks prototype was shown to weigh 9.5 lb, where as the actual physical prototype was shown to weigh lb. Both weights are considered very lightweight for aluminum prototypes and allow the fixture to be very portable. The automatic locking mechanism of the fixture makes the group s design no more difficult to use or involved in comparison to the wall mounting fixtures currently on the market. The only area that the group wished to improve upon is the cost of the fixture. Considering that this design was the first prototype created of its kind, it is believed that there is lots of room for improvement in terms of cost and manufacturing method of the fixture. 18 P age

19 Future Projections: The future of this project could be a marketable product. The main focus of this project is to design a fixture that will secure and display electric guitars safely. Once this has been done successfully, the scope of the project could be improved further and be sold in music stores around the world. The design goals of this project were to design a Door-Mounted Guitar Display Fixture to accommodate most Fender, Gibson, Schecter, Ibanez, Yamaha, and Jackson electric guitars models. Further development of this model could lead to accommodating acoustic and specialty guitars. The group believes that if this product were to be mass manufactured, the cost and weight of the product could be brought down drastically by using different manufacturing methods, and a different material selection. Towards the end of the project, the group began to research alternative materials that could be used for certain pieces of the assembly. Components that do not play a big structural role in the design could be made out of cheap lightweight PVC plastic, such as the square tube spine and the pulleys. The addition of ball bearings to the inside of the pulleys would help promote rotational movement and create a more sound design. Creating the internal guide blocks out of Delrin would help reduce the coefficient of friction of the linear movement of the design. In order to increase the longevity of the piece, the gear was chosen to be made out of nylon due to nylon s amazing resistance to wearing. Rather than mounting the gear rack to the inside edge of the gear channel with JB weld, it would be a better idea if the entire spine were to be manufactured by plastic injection molding with the rack already equipped in the mold. Perhaps the most important change to the design is the choice to change the material of the protective arms alloy aluminum was great for making a prototype, however, the absence of an endurance limit to aluminum makes this material a poor choice for a component that would be taking a repeated load. Instead, the group decided that a strong, lightweight material, such as fiberglass, would make a good choice for the arm material. Feedback to the formal presentation of this idea has made the group decide to pursue creating a patent for this product. Because there is no similar design currently on the market, the group believes that this product could be sold to the general public after the above modifications have been made to the design. 19 P age

20 References: "2.1.2 Engagement with Sprockets." The Complete Guide to Chain. Tsubakimoto Chain Co. Web. 22 June < "10 Best Guitar Brands." All News about Guitar. Revolution, 17 Apr Web. 10 June < "About Fender." Welcome to Fender.com. Fender Musical Instruments Corportation. Web. 10 June < "GFRP - Glass Fiber Reinforced Polymer. Lightweight, Durable Architectural Fiberglass." Custom Architectural Products in Cast Stone, GFRP, GFRC, GFRG and GFRS Stromberg Architectural Products. Stromberg Architectural. Web. 9 June < "Gibson USA." Gibson Guitar: Electric, Acoustic and Bass Guitars, Baldwin Pianos. Gibson USA. Web. 10 June < Mott, Robert L. Applied Strength of Materials. 5th ed. New Jersey: Prentice Hall, Print. Mott, Robert L. Machine Elements in Mechanical Design. 4th ed. Upper Saddle River, N.J.: Pearson/Prentice Hall, Print. "Specific Stiffness - Specific Strength." Cambridge University Engineering Dept - Materials Group. Cambridge University. Web. 8 June < Tabellion, Jan. "Carbon Fibre Reinforced Plastic (CFRP) Ingenieurparadies." Welcome ww.ingenieurparadies.de. Schunk Group. Web. 9 June < "Typical Properties of EPDM-NBR-CR Rubber." Products. Tokai Carbon Co. Web. 8 July < 20 P age

21 Appendix II: Model Distance Measurements Allowable Guitar Width and Thickness 21 P age

22 Allowable Neck Width 22 P age

23 Appendix V: Work Plan 23 P age

24 Appendix VI: Professional Resumes Matthew Bury 26 Longview Dr. Dartmouth, MA (508) EDUCATION Wentworth Institute of Technology, Boston, MA Bachelor of Science in Mechanical Engineering Technology August 2010 exp. COURSEWORK Statics Heat Transfer Computer Aided Manufacturing Strength of Materials Fluid Mechanics I & II Mechanical CAD Applications I &II Machine Design I & II Calculus I & II & III Manufacturing Processes TECHNICAL COMPETENCIES Engineering: [ProtoTrak] Machining, CNC lathe, Welding, Casting, CMM, Hard Gauging, Optical Comparators Design Software: Mechanical Graphics, AutoCAD, SolidWorks, Unigraphics, Benchman Software, EES Information Tech: Microsoft FrontPage, Word, Excel, and PowerPoint WORK EXPERIENCE Massachusetts Bay Transportation Authority October December 2009 Subway Operations Department Intern Drafted parts for the Type 7 and 8 subway trains such as sander tubes and brake calipers Participated in brake testing and maintenance procedures for the trains Performed measurements and inspected incoming parts Symmetry Medical, New Bedford, MA January May 2009 Quality Engineer Co-op Developed a Material Matrix based on raw material usage & industry standards for chemical and physical properties Performed part measurement and inspection Compiled data and performed statistical analysis on critical part feature to determine part verification to blueprint requirements Hawthorne Country Club, Dartmouth, MA June August 2009 Prep-Cook, Clubroom Cook and Dishwasher Prepared food for events such as weddings, banquets and bar mitzvahs Cooked food for members and golfers Cleaned dishes after events LAB EXPERIENCE Wood Block Design January May 2008 Programmed NC-Code on Benchman Software, then initiated it on the Techno-Isle gantry machine Redesign Air Engine September December 2007 Increased the net power output of the air engine to drive a particular conveyer system Collaborated with four classmates; particularly focused on the tolerance analysis and designing location of exhaust/intake holes Air Engine January May 2007 Machined a one cylinder piston air engine and casted the base from aluminum alloys 24 P age

25 Derek J. Iredale 22 Sunset Terrace Merrimac MA, (978) Education Wentworth Institute of Technology Boston, MA Bachelor of Science in Mechanical Engineering Technology August 2010 exp. GPA: 3.55/4.00 Dean s List Fall 2005-Spring 2008 Coursework Strength of Materials Thermodynamics I & II Dynamics Materials Science Cad Applications Fluid Mechanics Mechanical Design Intro to HVAC Manufacturing Processes Business Ethics Tech. Communications Electricity and Electronics Lab Experience Intro to HVAC Studied heating and humidification processes in an air conditioning demonstrator to detect sensible and latent heat changes and the affect on the output air. Calculated heating loads for sample buildings by quantifying heat loss through convection, conduction, and infiltration. Thermodynamics Analyzed heat transfer in various systems by collecting data and balancing energy equations to determine system efficiency and entropy gain. Determined the performance of a diesel charged engine by evaluating the unit output, thermal efficiency, fuel consumption, and cost of operation for power production. Technical Competencies Software- SolidWorks, AutoCAD, Microsoft Office (Word, Excel, and PowerPoint), and some experience with LabVIEW. Machining- Engine lathe, Vertical mill, Drill press, and Band saw. Experience Nuvera Fuel Cells. Billerica, MA 1/09-5/09: Research & Design Lab Intern. Maintained the stack durability testing lab by monitoring voltage changes and ensuring proper test stand performance. Disassembled hydrogen fuel cell packages at end of life and prepared data for failure analysis reports. Sullivan, Bazinet, and Bongio Inc. Ipswich, MA 05/07-09/07: Certification Trainee Maintained clean room environments using particle counters and adjusting airflows for Biogen Idec in Cambridge, MA. Helped install HVAC systems for companies such as Luminus in Billerica, MA, and Bio- Concept in Derry, NH. 25 P age

26 Eric David DuComb 1012 High St. Palmer, Ma (Cell) (413) EDUCATION Wentworth Institute of Technology Boston, Ma Bachelor of Science in Mechanical Engineering Technology, 2010 exp. Dean s list GPA COURSEWORK Structured Programming for Engineering and Technology Math I & II, Calculus I, II, III Physics I & II Mechanical Design I Manufacturing Processes, CAM Computer Aided Manufacturing Mechanical Graphics, Mechanical CAD Applications Thermodynamics Statics, Strength of Materials TECHNICAL COMPETENCIES Design: Hand sketching, Drawing, Auto CAD, SolidWorks, Unigraphics, Microsoft Word, Microsoft Excel, Microsoft PowerPoint and Microsoft FrontPage Fabrication: Writing G code, Programming Machines, Milling, Welding, Metal Work, Wood Working Software: Unigraphics, Auto CAD, SolidWorks, Benchman, Microsoft Office RELATED EXPERIENCE 1. Wentworth Institute of Tech. Project Lab assistant machine shop September 07 present Run Machines Bridgeport, Lathe, Band Saw, Drill press and EX. Mentoring fellow students on operating machinery properly Maintain Equipment 2. Massachusetts State, Dcr, Department of CONSERVATION AND RECREATION (Quabbin Reservoir) Summer Laborer Forest management, Operated Chain saw and forestry equipment Responsible for State Police boat docks. Perform experimental test s on invasive plant species 3. Olde Hadliegh Hearth and Home Full time summer South Hadley, Ma , part time through high school Wood and Gas, stove and fireplace installer / deliverer Installed / rigged chimney piping Shop Welder Fork truck operator INTERESTS Working on my jeep, Off Roading, Traveling, Welding, The Outdoors 26 P age