Ergonomics - Atlas Copco

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Percussive tools Percussive tools use the blow energy from an accelerated piston to create high forces. The high forces can be used to chip off steel or to set a rivet. Using the tool may, however, involve risk of injury from noise and vibration. Vibration controlled riveting hammers and bucking bars are frequently used in the aerospace industry. Where are the tools used? There are three different types of percussive tools: chipping hammers, scalers, and riveting hammers. The first two are commonly used in foundries, while the riveting hammer is mainly used in the aerospace industry. Since percussive tools are very effective they are commonly used for a variety of other applications, from the worker assembling guide pins in engine blocks to the sculptor chipping away at raw material in his studio. Working environment High noise levels are a typical problem with percussive tools. The machine noise can be muffled, but noise from the main source, the process, is difficult to reduce in a way that is physically acceptable to the operators. Vibration values are also high for percussive tools, in particular from the inserted tool. There is a general rule that the chisel in a chipping hammer, for example, should not be touched when the tool is being operated. Easy to say, but difficult in 41
42 practice. Sometimes the chisel has a round neck and the operator needs to guide it manually. Technically, this is to make the blow end flexible when cleaning a casting. From the point of view of safety, it is not good practice. Design for good ergonomics Modern machines are provided with muf- flers. When carrying out light cleaning of sand burnings on castings, the efficiency of the muffler can make a difference, but usually the process noise dominates. Control of vibrations in percussive tools has been more successful. Several methods have been used – for example, reducing the oscillating forces acting on the machine mass, or designing an isolation system which screens off the operator from the vibrating tool. For chipping hammers, where the process calls for high feed forces, the bow grip handle is often used to minimize the torque absorbed by the wrist. The trigger force and the feed force are in alignment and the trigger is often thumb-operated. When using percussive tools, the working posture often remains the same for long periods of time. This may lead to muscle overload and fatigue due to static forces acting on the hand-arm system. Safety protection Ear defenders, safety goggles and gloves are strongly recommended. Research is continu- ously being conducted into the development of anti-vibration gloves. At present such gloves are ineffective against the low frequency vibrations emitted by these tools. Operators working in heavy industry should wear protective headgear. To prevent the operator from holding the chisel, the machines are provided with a retainer and, in many cases, a hand grip that can be moved along the chisel. HanDle DeSiGn The open or closed bow grip, or D handle, is a typical feature of chipping hammers. Riveting hammers and scalers often have straight or pistol grips. Chipping hammer handles are designed to allow high feed forces to be applied for long periods. The trigger is thumb-operated and the trigger force is in alignment with the feed force. Riveting hammers are designed for high precision and, in principle, one working posture. The trigger function on these tools allows one-blow-per-cycle operation. external loaD During a chipping operation high feed forces may be needed, while the posture often
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 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: 40 SHoCK reaCtion Sudden changes in
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
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92 Temperature Hand-held power tool
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94 To ensure physical comfort durin
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96 Score 40 30 20 10 0 Bibliography
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98 the dynamic properties of the ma
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100 High motor power and fast clutc
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102 Score 40 30 20 10 0 shock react
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104 piezo-electric crystal. When th
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106 EN 50144 and EN 60745. Both ISO
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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
Page 157 and 158:
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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