Ergonomics - Atlas Copco

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design criteria for cold surfaces on the operator’s subjective pain feelings. From the point of view of operator comfort, the surface temperature of metal tool handles should not be lower than 4ºC if continuous operation is anticipated. Lower temperatures call for handle insulating materials or protective gloves. The use of insulating materials, such as plastic and wood, can greatly reduce the speed of cooling of the skin when it comes into contact with cold surfaces. Evaluation of temperature For evaluation the lowest permissible temperature is set to 4ºC. For the highest temperature, the burn threshold for a contact time of 10 minutes (48ºC) is used. Between these two limits a function has been assumed passing the weighting factor 20 at burn threshold. Material removal tools The temperature to be evaluated for these tools is the lowest or highest stabilized handle temperature measured at the handle surface when the machine is running at 50% of its maximum capacity in a brake at the laboratory. The temperature should be measured without holding the handle. The properties of the handle surface have a strong influence on the temperature and the operator’s perception of the temperature. A meaningful comparison between machines can only be made if the handle surfaces are similar. The decision to place a 50% load on the machine may be questioned. For example, the temperature of a grinder driven by a vane motor will increase when the machine is running free, due to friction between the vanes and the cylinder wall. Like- wise, its temperature will fall when running under load, due to expanding compressed air. In a real work situation, there are large fluctuations in the power output and conse- quently in the temperature. Percussive tools are tested in an energy absorber. For example, a steel ball absorber is used for vibration measurements. The tool is tested in a sequence of starts and stops based on calculations made from the known or assumed average using time of the tool per day. Assembly tools An assembly tool is often only used for a few seconds during each tightening sequence and temperature is rarely a problem unless the tool is used in a highly repetitive work situation. The machines are tested with maximum torque setting on a soft test joint in a sequence corresponding to the known or assumed average using time per day. 95
96 Score 40 30 20 10 0 Bibliography European Standard (CEN): 1994, Safety of machinery – Temperatures of touchable surfaces, EN 563. British Standards Institution (BSI): 1983, Medical information on human reaction to skin contact with hot surfaces, PD 6504. Eastman Kodak Company: 1983, Ergonomic design for people at work, Van Nostrand Reinhold Company, New York, Vol. 1. 0 10 20 30 40 50 0 50 68 86 104 122 Chen, F., Nilsson H., Holmer, I.: 1994, Cooling responses of finger in contact with an aluminum surface, Am Ind Hyg Assoc J 55: 218-222. Chen, F., Nilsson H., Holmer, I.: 1994, Finger cooling by contact with cold aluminium surfaces – effects of pressure, mass and whole body thermal balance, Eur J Appl Physiol 69: 55-60. Fig. 3.11 The score for temperature can be found in this figure. ºC ºF
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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
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Good ergonomics is good economics W
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10 SOCIOLOGY INDUSTRIAL SOCIOLOGY S
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12 Work organization No organizatio
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1 outside the production system, an
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1 A seated operator usually has goo
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1 without stretching the trunk. The
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20 The arm sling as a preventive me
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22 Extreme working postures in real
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2 Working with high feed forces req
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2 Working areas of a standing works
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2 body is lifted or tilted, or the
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30 The team is an important factor
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32 Grinders Grinders and sanders ar
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34 HanDle DeSiGn The hand grips on
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36 DUSt anD oil Although the machin
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38 Working environment In general,
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40 SHoCK reaCtion Sudden changes in
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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 and 60: 58 High torque nutrunners for use w
Page 61 and 62: 60 Wheel nuts on trucks and buses a
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: 94 To ensure physical comfort durin
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
Page 111 and 112: 110 In the GTG 40 grinding machine,
Page 113 and 114: 112 RRH machines serves two functio
Page 115 and 116: 114 be noted that declared values b
Page 117 and 118: 116 Noise Noise was the first envir
Page 119 and 120: 118 value for 8 hours’ exposure t
Page 121 and 122: 120 We can start by looking at the
Page 123 and 124: 122 This is done with a minimum inc
Page 125 and 126: 124 microphones at a distance of 1
Page 127 and 128: 126 coated with dust or damaged by
Page 129 and 130: 128 This method has not been used b
Page 131 and 132: 130 tool cabinet. Many workplaces h
Page 133 and 134: 132 lubrication. Made from a compos
Page 135 and 136: 134 Grinder GTG 40 F085 The relevan
Page 137 and 138: 136 were simulated by fitting a whe
Page 139 and 140: 138 Drill LBB 26 EPX-060 The releva
Page 141 and 142: 140 applied to the center of the dr
Page 143 and 144: 142 Chipping hammer RRF 31 The rele
Page 145 and 146: 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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