1 / 21

IE 327 Introduction to Work Design Dr. Andris Freivalds Class #7

IE 327 Introduction to Work Design Dr. Andris Freivalds Class #7. Ex. 4-1 Lifting Box into Car. 30 lb box from ground into trunk Twist 90 ° to pick up Ground level → V = 0 Min horizontal → H = 10 Trunk → H = 25, V = 25 One-shot lift, FM = 1 No cutouts, CM = 0.95.

xuxa
Download Presentation

IE 327 Introduction to Work Design Dr. Andris Freivalds Class #7

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. IE 327 Introduction to Work Design Dr. Andris Freivalds Class #7 IE 327

  2. Ex. 4-1 Lifting Box into Car • 30 lb box from ground into trunk • Twist 90° to pick up • Ground level → V = 0 • Min horizontal → H = 10 • Trunk → H = 25, V = 25 • One-shot lift, FM = 1 • No cutouts, CM = 0.95 IE 327

  3. Ex. 4-1 Lifting Box into Car RWLor = 51(10/H)(1-.0075|V-30|)(.82+1.8/D)(1-.0032A)FMxCM RWLdest = 51(10/H)(1-.0075|V-30|)(.82+1.8/D)(1-.0032A)FMxCM IE 327

  4. IE 327

  5. COUPLING MULTIPLIER IE 327

  6. Effect of Multipliers - 1 IE 327

  7. Effect of Multipliers - 2 IE 327

  8. Effect of Multipliers - 3 Frequency Multiplier IE 327

  9. Lifting Interventions • Decrease H • Avoid twisting • Turntables • Extra step • Lift tables • Tilt tables • Hoists IE 327

  10. CTD and TOOL DESIGN • Cumulative trauma disorders (CTDs) • Work-related musculoskeletal injuries • Due to repeated microtrauma from • High force, high repetition • Extreme joint motions, lack of rest • AKA: repetitive motion injuries • Cost to industry • 15-20% of workers • Average of $30,000/case • OSHA effort ‘Ergonomics Standard’ IE 327

  11. HAND ANATOMY and CTDs • Carpal tunnel syn. • Tenosynovitis • Tendinitis • Trigger finger • White finger • Raynaud’s disease • Rotator cuff • Thoracic outlet syn. IE 327

  12. HAND/WRIST POSTURES • Maintain neutral wrist • Flexion/extension • Radial/ulnar deviation • ↓ grip strength 20-30% • Arms hang down • Abduction fatiguing • Overhead work is very bad IE 327

  13. TYPES OF GRIP Opt = 1.5 in Power > Lateral > Two pt 100 lbs > 29% > 15% IE 327

  14. CTD risk analysis • Similar to NIOSH • 4 factors • Frequency • Posture • Force • Misc • Index < 1 IE 327

  15. IE 327

  16. COMMENTS ON CRIMIPER IE 327

  17. TOOL DESIGN #1 • Grip span, opt = 2¾-3¼ in • F = ½-⅔ M strength • Handedness, ↓10% • Strength, 90% can • Avoid tissue compression • Handle length ≥ 4 in IE 327

  18. TOOL DESIGN #2 • Triggers→ trigger finger • Force < 2 lbs • Use 2-3 fingers (not 1) • < 10,000 motions/day • Use strongest finger • Thumb ~ 16 lbs • Middle ~ 88% • Index ~ 81% • Ring ~ 69% • Little ~ 44% IE 327

  19. TOOL DESIGN #3 • Handle – grip • Circular crossection (double frustum) • Wood, plastic - ↓ shock, ↓ conductivity, friction • Metal bad (unless covered with rubber) • Weight < 5 lbs • Gloves • Add 0.2-1 in to hand diameter • ↓ grip strength & dexterity 10-20% • Tradeoff: ↑safety vs. ↓ performance IE 327

  20. POWER TOOLS • Provide power • But vibration • But reaction torque • Automatic shutoff • High RPM, high power • Reaction bar • Use proper tool in proper orientation • In-line vs. pistol grip • Neutral wrist IE 327

  21. IE 327

More Related