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Unformatted text preview: HAND TOOL DESIGN HAND TOOL DESIGN ASSOCIATE PROF. DR. SITI ZAWIAH MD. DAWAL DEPT. OF ENGINEERING DESIGN AND MANUFACTURE UNIVERSITY OF MALAYA Introduction Introduction Human hand is able to perform a large variety of activities ranging from those that require fine control to others that demand large forces. Hand tasks can be divided: Hand tasks can be divided: Fine manipulation of objects with little displacement and forces. Fast movements toward the object, requiring moderately accuracy to reach the target but a fairly small exertion of force. Forceful activities with little or moderate displacement Forceful activities with large displacements Designing And Selecting Designing And Selecting Good Hand Tools Fit the Tool Fit the Tool Hand tools need to fit the contours of hand Hand tools need to held securely with straight wrist and suitable arm postures Hand tools must utilize strength and energy capabilities without overloading the body. Many methods of gripping Many methods of gripping There are two basic grips: There are two basic grips:
Power grip Precision grip Power Grip Power Grip Force parallel to forearm Force at an angle of forearm Force acting on a moment forearm Power grip is used for force or holding heavy product Pinch Grip Pinch Grip Tools is held between the distal ends of one or more fingers 4 types: Lateral pinch Pulp pinches Palm pinch Finger press Avoid Tissue Compression Avoid Tissue Compression Handle Design Handle Design Oblique thrust line Oblique thrust line Formfitting Formfitting Pulp Pinch Strength Capability Pulp Pinch Strength Capability Proper orientation of power Proper orientation of power tools in workplace Factors to consider Factors to consider Design tools so that they can be used by either hand by most individuals Avoid repetitive finger action Use the strongest working finger Handle opening ...
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- Summer '10