MECH SENIOR MECHANICAL DESIGN PROJECT PROFS. ROBERTS & ROURKE SUMMER 2010 GROUP 2

Transcription

1 MECH SENIOR MECHANICAL DESIGN PROJECT PROFS. ROBERTS & ROURKE SUMMER 2010 GROUP 2

2 Summary Problem Definition / Need Objective Data Acquisition / Design Parameters Design Concepts Kinematic Solutions Prototype Fabrication Testing Future Plans Conclusion

3 Problem Definition There are no guitar display fixtures on the market that can keep a guitar off of the floor and out of harms way, without the requirement of permanent drilling into the wall.

4 Existing Designs Floor stands leave the guitar in harms way and take up floor space. Wall mounted fixtures consist of permanent mounting holes, damaging walls and causing unnecessary costly repairs in apartments or dormitories.

5 Objective Design a portable, door-mounted guitar display for a max 15 lb guitar that protects the electric guitar by elevating it above floor level and restricting any movement caused by opening and closing of a door. Keep manual operation to a minimum Able to adapt to a variety of popular electric guitar / bass model shapes Minimize bulkiness of fixture, allowing for clean display of guitar. Utilize Lightweight / Cost effective materials

6 Who Will Benefit? Any musicians who lease rent apartments or live inside a college dormitory. Musicians who need to keep their guitar elevated for protection against pets or small children. Any musician who desires easy access to their instrument, while still being able to display it out in the open and keep it safe.

7 Data Collection Measurements were taken from various guitar models found on the wall at Daddy s Junky Music on Mass Ave.

8 Design Parameters - Over 20 of the most popular guitar and bass guitars were measured. - Provided base measurements - Determined a range for prototype operation for the leading guitar models. Model Length (in) Current Guitar Measurements Thickness (in) Neck Width (in) Body Width (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

9 Design Matrix

10 Early Concept Designs - D Chain and Sprocket Design Planetary Gears to bring pieces together Linear motion allows for adjustability. As guitar is placed on hanger, bottom is raised to secure the base. System Equilibrium

11 Final Design - B Linear motion is contained within the spine Rotating Arms Protect from damage Utilization of pulleys

12 Pulley Relations

13 Rotational to Linear

14 Spring Conditions

15 Spring Conditions

16 Prototype Fabrication 6061 aluminum 2 x 2 OD 5/8 thick wall with a internal surface finish was used as the backbone for the project. Considerations - Internal moving components - Guide Block(s) tolerances - Friction Advantages - Lightweight - Easily machined - Readily available - Durable

17 Prototype Fabrication Pulleys - Outer most pulleys were turned out of 6061 aluminum at a diameter of 3 width of Center most pulley was turned out of 6061 aluminum at a diameter of 1 width of 1 - Offset pulley risers by 0.5 for use of separate belts; allowing maximum belt surface area = no slipping - Center pulley rotates ¾ turn while the outer pulleys move ¼ turn - 3:1 Ratio

18 Prototype Fabrication Internal Components - Each and every part was modeled using Solidworks, and dimensioned drawings followed. - Were milled on a Proto-Trak vertical milling machine with very tight tolerances for alignment and mating issues. - Made out of 6061 Aluminum stock - Counter bores and relief cuts made it possible for maximum functionality out of major components.

19 Prototype Fabrication SHEETMETAL WORK - Made out of Guage sheet metal. - Metal was annealed with Oxy- Acetylene torches to relieve stress, which allowed for easy and clean bends without stress related hair fractures.

20 Material 6061 Aluminum is a precipitation hardening aluminum alloy, containing magnesium and silicon as its major alloying elements. - The mechanical properties of 6061 depend greatly on the temper, or heat treatment, of the material. - Typical properties of aluminum alloy 6061 include: Medium to high strength Good toughness Good surface finish Excellent corrosion resistance to atmospheric conditions Can be anodized Good weldability and brazability Good workability Widely available Component Amount (wt.%) Aluminium Balance Magnesium Silicon Iron Max. 0.7 Copper Zinc Max Titanium Max Manganese Max Chromium Others 0.05

21 AISI 1020 Stress analysis on the Guitar hanger. When a 15 lb load is applied there is a Max Stress= 25,796 psi

22 Displacement in the Y-Direction Displacement from 15 lb load= in

23 Door Hanger Analysis 25 lb force applied Max Stress = 6152 Material: AISI thickness

24 Arm Analysis-Applying a 15 lb Force (Caused by minor impact) Max Stress is 14,635 psi Material: 6061-T6- Alloy

25 Max Displacement in the Z-Direction = 0.45 in

26 Analysis Overview Applied Lod (lb) Max Stress (psi) Yield Stress (psi) Max Displacement (in) Part Material FoS Guitar Hangar AISI Door Mount AISI X Arm 6061-T Max Force on Arm to yield = 40 lb

27 Final Budget 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. Hardare 10 Total

28 Project s Future Mass Production Capability Interchangeable / Extendable Arms to accommodate large body acoustic instruments Addition of door straps to restrict fixture movement

29 Alternative Materials IF MASS PRODUCED - Pulleys Made out of Plastic - Arms Low-cost composite such as fiberglass or fiberglass reinforced plastic (FRP) - Spine Plastic injection mold, with gear rack incorporated (various colors) - Centering Guide Blocks High density plastic with helicoil inserts - Gear Nylon (wear resistant)

30 Conclusion Holds a 15 lb guitar Restricts DOF limiting movement Safely elevates guitar Portable + Automated locking Adapts to many guitar models Prototype weighs 10lb 4 oz Relatively low cost for a prototype

31 Work Plan

32 So Now what? More in depth FEA testing of assemblies Testing of different materials Spring insertion into prototype Finish SolidWorks Animation Motion Analysis Poster board Formal Write-up

33 Questions or Comments Thank You