Ergonomics - Atlas Copco

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production of heavy vehicles such as trucks, buses and off-road vehicles. the working environment The high torque nutrunner is usually preferred in modern industrial situations as it contributes to a good working environment. The workstation can be stationary or on a moving line. The tool has virtually no negative impact on the working environment. Weight can be a negative factor for the operator, therefore in most applications the tools are suspended from balancers. Design for good ergonomics During the 1970’s, production engineers tried to replace impact wrenches with stalltype nutrunners in order to reduce noise and improve accuracy. However, operators complained of the increased tightening times (about three times longer than impact wrenches). This was particularly noticeable in assembly line production where the entire balance of the line was changed. A popular solution was a new tool design incorporating two motors – a fast motor for rapid nut run-down and an additional, slower motor for the final tightening sequence. Tools with reaction bars are heavier than conventional tools. This must be considered in tool installation, for example, using balancers or articulating arms. Safety The major safety risk in operating these machines is pinching, crushing, or severing of the fingers. The forces acting between the reaction bar and the workpiece are considerable and could easily sever a finger. Thus, all machines carry a warning label: “Never hold the reaction bar while tightening”. HanDle DeSiGn Small machines usually have pistol grips. Larger tools tend to be front-heavy due to the extra gears required. A handle placed under the machine, as near to the center of gravity as possible, minimizes operator discomfort. external loaD High torque nutrunners are heavy and should therefore be suspended from balancers. During tightening, the reaction forces are absorbed by the reaction bar instead of the handle. The reaction bar may make the tool front-heavy, thus exposing the operator’s wrist to bending torque. WeiGHt A high-torque machine, equipped with transducers for measuring torque and angle, is a heavy tool, therefore an articulating arm is recommended. Since the larger machines 59
60 Wheel nuts on trucks and buses are a typical application for high torque nutrunners. are not used for highly repetitive tasks, the operator is not exposed to high dynamic forces from the motion of the machine. teMPeratUre These tools do not pose a temperature problem. SHoCK reaCtion The reaction bar eliminates the shock reaction in the handle. ViBration Declared vibration values are
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Power Tool Ergonomics E V A L U A T
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Acknowledgements While doing resear
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How to get the best out of this boo
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Work with international standards I
Page 9 and 10: Good ergonomics is good economics W
Page 11 and 12: 10 SOCIOLOGY INDUSTRIAL SOCIOLOGY S
Page 13 and 14: 12 Work organization No organizatio
Page 15 and 16: 1 outside the production system, an
Page 17 and 18: 1 A seated operator usually has goo
Page 19 and 20: 1 without stretching the trunk. The
Page 21 and 22: 20 The arm sling as a preventive me
Page 23 and 24: 22 Extreme working postures in real
Page 25 and 26: 2 Working with high feed forces req
Page 27 and 28: 2 Working areas of a standing works
Page 29 and 30: 2 body is lifted or tilted, or the
Page 31 and 32: 30 The team is an important factor
Page 33 and 34: 32 Grinders Grinders and sanders ar
Page 35 and 36: 34 HanDle DeSiGn The hand grips on
Page 37 and 38: 36 DUSt anD oil Although the machin
Page 39 and 40: 38 Working environment In general,
Page 41 and 42: 40 SHoCK reaCtion Sudden changes in
Page 43 and 44: 42 practice. Sometimes the chisel h
Page 45 and 46: 44 SHoCK reaCtion These tools do no
Page 47 and 48: 46 heavy, assembly work is often hi
Page 49 and 50: 48 depends on its inertia. The same
Page 51 and 52: 50 bolts. Unfortunately there are a
Page 53 and 54: 52 The low reaction torque in impul
Page 55 and 56: 54 the working environment A typica
Page 57 and 58: 56 Today, the angle nutrunner can b
Page 59: 58 High torque nutrunners for use w
Page 63 and 64: 62 Introduction A basic ergonomic p
Page 65 and 66: 64 Handle design The handle of a ha
Page 67 and 68: 66 Arteries Veins (superficial) Vei
Page 69 and 70: 68 Handle size Since a tool handle
Page 71 and 72: 70 However, if the texture is too c
Page 73 and 74: 72 Bibliography Chaffin, D.B. and A
Page 75 and 76: 74 Fig. 3.3 The same feed force app
Page 77 and 78: 76 Pushing and pulling Pushing a to
Page 79 and 80: 78 the object, the shape of the obj
Page 81 and 82: 80 Safety factor a 2 Frequency of t
Page 83 and 84: 82 Comments for different tool type
Page 85 and 86: 84 The trigger is either operated b
Page 87 and 88: 86 used in one handed operations. T
Page 89 and 90: 88 Weight The weight of a hand-held
Page 91 and 92: 90 stability of grip, the center of
Page 93 and 94: 92 Temperature Hand-held power tool
Page 95 and 96: 94 To ensure physical comfort durin
Page 97 and 98: 96 Score 40 30 20 10 0 Bibliography
Page 99 and 100: 98 the dynamic properties of the ma
Page 101 and 102: 100 High motor power and fast clutc
Page 103 and 104: 102 Score 40 30 20 10 0 shock react
Page 105 and 106: 104 piezo-electric crystal. When th
Page 107 and 108: 106 EN 50144 and EN 60745. Both ISO
Page 109 and 110: 108 hole of the wheel are wider tha
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110 In the GTG 40 grinding machine,
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112 RRH machines serves two functio
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114 be noted that declared values b
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116 Noise Noise was the first envir
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118 value for 8 hours’ exposure t
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120 We can start by looking at the
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122 This is done with a minimum inc
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124 microphones at a distance of 1
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126 coated with dust or damaged by
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128 This method has not been used b
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130 tool cabinet. Many workplaces h
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132 lubrication. Made from a compos
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134 Grinder GTG 40 F085 The relevan
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136 were simulated by fitting a whe
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138 Drill LBB 26 EPX-060 The releva
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140 applied to the center of the dr
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142 Chipping hammer RRF 31 The rele
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144 SHOCK REACTION There are no sho
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146 Riveting hammer RRH 06 The rele
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148 WEIGHT The weight is 1.3 kg, sc
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150 Screwdriver LUM 22 PR4 The rele
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152 This gives a score of 9. In pra
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154 Impulse nutrunner EP9 PTX80-HR1
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156 Due to friction in the hydrauli
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158 Electric nutrunner ETP ST32-05-
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160 WEIGHT The electric nutrunner i
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162 Angle nutrunner LTV 29 R30-10 T
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164 operator equal to installed tor
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166 Electric angle nutrunner Tensor
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168 WEIGHT The electric nutrunner i
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170 High torque nutrunner LTP 51 Th
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172 Score 40 30 20 10 0 NOISE The d
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Ergonomics - Atlas Copco

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