university of puerto rico mechanical engineering department ha-s hide-away shank screwdriver...
TRANSCRIPT
University of Puerto RicoMechanical Engineering Department
Ha-S Hide-Away Shank Screwdriver
Lynnette M. Méndez-Galarza
Jean Carlos Rivera
Mario Rosario Adorno
Reinaldo Santiago Bermúdez
Vijay K. Goyal, PhD -- Faculty AdvisorCourse:
Computer Aided Design
Problem description
• Adult accidents:Dropping the toolMisplace the tool
• Children’s curiosity:Poking body partsPlaying with power
outlets • Compact:
Difficult PortabilityAwkward Storage
Picture: http://clerccenter.gallaudet.edu/AcademicTeams/EC-ed/2001-2002/electric/images/Screwdriver%20EN.jpg
Objectives
• Minimize risk of an accident with a screwdriver.
• Child-proof
• Compact the screwdriver for easy storage and portability
Possible Solutions
First idea - Hide-Away Gear Shank
Possible Solutions
Second idea - Hide-Away Antenna Type Shank
Possible Solutions
Third idea - Hide-Away Shank
Idea Selection
Criteria Score(0-10)
DatumScore
Idea IScore
Idea IIScore
Idea IIIScore
Weight 2 0 -1 -2 -1
Size 4 0 2 2 2Safety 10 0 1 1 2Versatility 7 0 2 2 2Appearance 3 0 1 2 2Additional Features 3 0 1 1 2
Production Cost 3 0 -2 -2 -2
TOTAL 32 0 4 4 7
Total Positive N/A 0 7 8 10
Total Negative N/A 0 -3 -4 -3
Weighted Total N/A 0 30 31 46
*Datum-Regular Screwdriver
Selected Design Specifications
BITBOX
Selected Design Specifications
Optimization Analysis
Minimize weight
cc ggxxggxxxf /*)75(.*/)1(*)(min 22
1222
11
• Everything with a subscript “1” refers to the shank properties
• Everything with a subscript “2” refers to the handle properties
Optimization Analysis
• Method of Lagrange MultipliersConstraints:
LaGrange Equation:
0*5.1
32)(
31
1 yx
Txg
0
*2)(
21
2 yx
P
A
Pxg
03)( 23 Xxg
)5()3(29700979.3
29700729.25
*)75(.142.0*)1(911.0)(x, 242321
231
122
12
12
XX
xxxxxx
05)( 24 Xxg
Optimization Analysis
)5(**
)3(**
29700979.3
**
29700729.25
**
0)75(.1442.0*911.0
0958.719.77
*)75(.284.0)1(*822.1
2444
2333
21
222
31
111
432
12
12
31
241
121211
Xg
Xg
Xg
Xg
XXX
XXXXXX
X
Optimization Analysis
0
0.071
0
0
3
0.142
4
3
2
1
2
1
X
X
!...02)(
!...00)(
!...029502)(
!...020714)(
GOOD! :Defined...194216.0)(
*4
*3
*2
*1
*
GoodXg
GoodXg
GoodXg
GoodXg
Xf
Solution: K-T Conditions
ANSYS Analysis
• Preprocessor
• Real Constants
• Material Properties
• Modeling
• Meshing
• Solution
ANSYS Analysis
ANSYS Analysis
ANSYS Analysis
Cost Analysis
Part / process PricePolymer 8’ $65.04Stainless Steel Rod (303) - 6’-5/32”R $7.48Stainless Steel Tube (304) - 12”-5/16”R $4.59Bits (16pzs) $3.00Bitbox $5.00Miscellaneous $5.00Turning @ $30/hr $0.50Total of one design $90.61
Cost Analysis
Part / process PricePolymer – 3” $2.00Stainless Steel Rod (303) - 6’-5/32”R $0.30Stainless Steel Tube (304) - 12”-5/16”R $0.80Bits (16pzs) $3.00Bitbox $5.00Miscellaneous $5.00Turning @ $30/hr $0.50Total per screwdriver $16.60
Conclusions
•Optimum value• 3” long• 0.15” radius
•Stresses do not exceed safe limits•Easy storage•Child-proof
Peace of mind now comes in a small, practical and attractive
package: the Ha-S.
(KISS)
Questions or Comments