Ergonomics - Atlas Copco

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teMPeratUre Low temperatures in the handles of pneumatic grinders can sometimes be annoying and are due to the expansion of compressed air in the motor. The outlet air should be guided away from the handles. When grinding for long periods, the entire grinder housing can grow cold and the low temperature can be transmitted to the handles. These must be covered with an insulating material. The opposite problem can occur in elec- trical grinders where the motor heats up during use. Machines with angle gears also have a tendency to get hot. SHoCK reaCtion The handles of a grinding machine transmit only a small amount of jerk. When the machine is started, forces act on its distrib- uted mass or inertia. The acceleration se- quence takes about 0.5 sec. for a pneumatic machine, depending on wheel size. The operator can cope easily with the reaction force and the starting time is so long that it can hardly be considered a jerk. For large electric machines equipped with on/off triggers, however, the operator must be prepared for the acceleration forces. ViBration The level of handle vibration for a grinder in use depends on the tool fitted. The main source is the imbalance of the wheel. A wheel that is slightly out of true will also add to the vibration value. The declared value is measured using an artificial wheel with a defined imbalance in accordance with an international standard. The vibration is often measured halfway along the length of the handle. noiSe The actual grinding process is the dominant noise source. A grinder driven by compressed air emits motor noise, irrespective of whether it has a vane or a turbine motor. The noise typically produced by a vane motor has a dominating frequency corresponding to the rotational speed of the motor multiplied by the number of vanes in the motor. The turbine generates broad band air stream noise. In electric tools, noise is generated by the gears and by the fan used to create the cooling air flow. The declared value for noise in the operator’s instructions is measured with the machine running free, since process noise is unique for every workplace and therefore cannot be predicted. 35
36 DUSt anD oil Although the machine itself does not gener- ate dust, the exhaust or cooling air whirls up a certain amount of dust. Other sources are the process and the general dust situa- tion in the working environment. To lower the operator’s exposure to dust, a ventilated grinding booth can be used. A more efficient way is to equip the grinder with a dust collector and connect it to a spot- suction system. Many vane motor driven grinders require lubrication and oil is added to the air inlet. Hand-held grinding is often more flexible than using numerically controlled machines. In machines with low outlet velocities the oil will leave the outlet in the form of drops. A high velocity outlet atomizes the oil which is ejected as an airborne mist. How this affects the operator depends on the efficiency of the ventilation system in the workplace. One way to reduce physical exposure is to provide the air inlet with a dosol lubricator, limiting the amount of oil entering the machine. Machines driven by turbines, and electrically driven grinders, are oil free.
Page 1 and 2: Power Tool Ergonomics E V A L U A T
Page 3 and 4: Acknowledgements While doing resear
Page 5 and 6: How to get the best out of this boo
Page 7 and 8: 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: 34 HanDle DeSiGn The hand grips on
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 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 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
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
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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
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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
Page 147 and 148:
146 Riveting hammer RRH 06 The rele
Page 149 and 150:
148 WEIGHT The weight is 1.3 kg, sc
Page 151 and 152:
150 Screwdriver LUM 22 PR4 The rele
Page 153 and 154:
152 This gives a score of 9. In pra
Page 155 and 156:
154 Impulse nutrunner EP9 PTX80-HR1
Page 157 and 158:
156 Due to friction in the hydrauli
Page 159 and 160:
158 Electric nutrunner ETP ST32-05-
Page 161 and 162:
160 WEIGHT The electric nutrunner i
Page 163 and 164:
162 Angle nutrunner LTV 29 R30-10 T
Page 165 and 166:
164 operator equal to installed tor
Page 167 and 168:
166 Electric angle nutrunner Tensor
Page 169 and 170:
168 WEIGHT The electric nutrunner i
Page 171 and 172:
170 High torque nutrunner LTP 51 Th
Page 173 and 174:
172 Score 40 30 20 10 0 NOISE The d
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Ergonomics - Atlas Copco

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