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Hand tool design
- 1. Hand Tool Design Submittedto Dr. Engr. Mohammad Iqbal Professor Industrial & Production Engineering, Shahjalal University of Science & Technology,Sylhet Industrial & Production Engineering, Shahjalal University of Science & Technology Submitted By Group B4 Tanni Das 2013334054 Kyaw Zaw Thowai 2013334055 Aminul Islam 2013334056 K A M Shahrier 2013334057 Mahbub Alam 2013334058 Ali Akbar Tanim 2013334060
- 2. Industrial & ProductionEngineering, Shahjalal University of Science & Technology and tool is any tool that is powered by . hand (manual labor) rather than by an engine. Hand tool aid the Human for Cutting, smashing, scraping, and piercing. Fit the work. Fit the user and hand. Not create injuries. H
- 3. Industrial & ProductionEngineering, Shahjalal University of Science & Technology Handled with power grip or with a precious grip. Small or large Flexible or, stiff One can design special purpose hand tool for specific task Possible to combine several hand tools into one. Fig: A special Handtool A tool use in multipurpose task at a time can be said as a special Hand tool. It saves time and make work easier. E.g. Hammer with an extension pulling nails, pliers with Hammer parts etc.
- 4. Fittingthetask Power Grip Thehand makes a fist with the forefinger on one side and the thumb reaching around. It can be differentiate by direction of force i)Force parallel to the forearm. E.g. saw; ii) Force at angle to fore arm. E.g. Hammer iii)Torque about the fore arm. E.g. Screwdriver Industrial & Production Engineering, Shahjalal University of Science & Technology Saw Hammer Screw driver
- 5. Precision Grip Industrial &Production Engineering, Shahjalal University of Science & Technology Internal Precision Grip The tool is held inside the hand. E.g. A table knife External Precision Grip The tool is pinched by the thumbs . against the index finger and the middle finger. E.g. A pen. Fig: Gripping a table Knife Fig: Writing by pen
- 6. Industrial & ProductionEngineering, Shahjalal University of Science & Technology Hand Tools Power Tools Hand tools are devices for performing work on a material or a physical system using only hands Power tools are tools powered by an electric motor Hand tools are propelled only by human power Power tools always have a motor Hand tools mechanism is very easy Power tools mechanism is not easy as hand tools It is environment friendly and cheaper but take more time than power tools Power tool save a considerable amount of time and effort in a larger project.
- 7. Industrial & ProductionEngineering, Shahjalal University of Science & Technology Good Pistol Handle Vertical surface Elbow height Bad Pistol Handle Horizontal surface Elbow height Bad Straight Handle Vertical surface Elbow height Good Straight Handle Horizontal surface Elbow height Bad Straight Handle Horizontal surface Below elbow height Good Piston Handle Horizontal surface Below elbow height
- 8. Industrial & ProductionEngineering, Shahjalal University of Science & Technology Fig: Maximum grip strength for male and female employees in electronics manufacturing
- 9. Industrial & ProductionEngineering, Shahjalal University of Science & Technology
- 10. Right handedtools for left handed users create awkward situation. Awkward postures may cause to use more force. Cut-outs for the fingers are responsible Awkward wrist position results in a loss of strength It is responsible for CTD It affects torque exertion capability Awkward wrist position (Terrell and Pursell-1976) : Decreases grip strength by 12% Flexion/extension by 25% Radial/ulnar deviation by 15% Prevention: Hand-tool should be designed both the left handed & right handed user. Design hand-tools by hand anthropometry Industrial & Production Engineering, Shahjalal University of Science & Technology
- 11. Industrial & ProductionEngineering, Shahjalal University of Science & Technology Cumulative Trauma disorder (CTD) Repetitive usage of hand tools Wear & tear on tissue on the joint. Vibration-Induced Injuries Hand tool vibration 1)Reynaud’s disease: Hand tool vibration in the frequency range 50-100 Hz 2)Dart’s disease: Vibration frequencies around 100 Hz
- 12. Industrial & ProductionEngineering, Shahjalal University of Science & Technology 2)Stiffness and numbness Reduction of blood flow Gradual loss of muscle control of the hand 1)White finger disease Reduction in blood flow to the hand and the finger Fig: White finger disease Fig: Stiffness and numbness
- 13. Industrial & ProductionEngineering, Shahjalal University of Science & Technology Aim: To increase operator comfort, convenience and controllability of hand tools . Guidelines: For precision grip Grip between thumb and finger Grip thickness is 8 to 13 mm Grip length minimum 100 nm Toll weight maximum 1.75 kg Trigger activated by distal phalanges of fingers with fast release mechanism.
- 14. Industrial & ProductionEngineering, Shahjalal University of Science & Technology For power grip Grip with entire hand Grip thickness 50-60 mm Grip length minimum 125 mm Grip force maximum 100 m Grip shape non-cylindrical Tool weight maximum 2.3 kg, 1.2 kg is preferable Trigger activated by thumb with locking mechanism
- 15. Industrial & ProductionEngineering, Shahjalal University of Science & Technology Grip surface smooth Slightly compressible and non conductive Avoid vibration, Particularly in the range of 50-100 Hz Design Handles for use by either hands Keep the wrist straight in the handshake orientation Tool weight balanced about the grip axis Eliminate pinching hazard
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