Design of an ergonomic control lever for wheel loader attachments

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Working postures of L90F The operator of the L90 controls the tilt lever solely with his thumb and the lift lever with his index finger and the middle finger with extension to produce force. A great radial deviation of the wrist in can be seen when he pulls the tilt lever towards himself, left image (figure 6.6). When doing pallet fork work he uses his thumb to push the 3 rd function lever and the index finger to pull the lever towards him. He changes the grip when only using the lift and tilt lever, so that the thumb controls the tilt lever and the index finger and middle finger controls the lift lever (right image in figure 6.7). During this operation the thumb and index finger are stretched out which gives a decreased strength in the thumb. The use of the little finger in the left image reveals yet another stretched posture and use of weak muscles. Figure 6.6 working postures of L90F when using 1 st and 2 nd function (Changing attachment) Figure 6.7 working postures of L90F when using 1 st and 2 nd and 3 rd function (Pallet fork work) 50
Working postures of L120F The operator of the L120F uses the thumb and index finger to control the tilt lever and uses the ring and little finger to control the lift lever. The hand and wrist does not change position that much more than a slight radial deviation of the wrist, see right image (figure 6.8). When doing snowplowing work he has three different grip positions, either on the 3 rd function and 4 th function lever, the lift and tilt lever (figure 6.9) or on all four levers. The two first grip positions (Left image in figure 6.9 and left image in figure 6.8) require that the operator change the grip more frequently than when gripping on all four levers. But, that posture makes the operator to stretch the thumb and little finger resulting in a weakened grip. Figure 6.8 working postures of L120F when using 1 st and 2 nd function (Planning work) Figure 6.9 working postures of L120F when using all four functions (Snowplow work) 51
Page 1 and 2: Design of an ergonomic control leve
Page 3: Acknowledgements This thesis work h
Page 7 and 8: Content 1 Introduction ............
Page 9 and 10: 1 Introduction The underlying reaso
Page 11 and 12: 1.3 Question formulation The studie
Page 13 and 14: 2 Current situation To get a deeper
Page 15 and 16: Figure.2.3. Control lever unit with
Page 17 and 18: Figure 2.4.Lifting and tilting the
Page 19 and 20: 2.2.2 Technical terms related to jo
Page 21 and 22: 3 Theory The theory research gather
Page 23 and 24: Angles of movement The hand has the
Page 25 and 26: 3.1.4 Ergonomic issues related to t
Page 27 and 28: 3.2 Cognitive ergonomics It seems t
Page 29 and 30: 3.3 Standards and recommendations T
Page 31 and 32: 4 Methods This chapter consists of
Page 33 and 34: Simulation interview gives users vi
Page 35 and 36: 4.3.3 Morphological matrix Morpholo
Page 37 and 38: 5 Project implementation This chapt
Page 39: Concept generation Idea generation
Page 42 and 43: Figure 6.1 the system description.
Page 44 and 45: machine operator. Because of this,
Page 46 and 47: 6.2.2 Analysis of wheel loader task
Page 48 and 49: 6.2.3 Observation study The purpose
Page 52 and 53: Discussion observation study The fi
Page 54 and 55: Figure 6.11 Jack simulation - Good
Page 56 and 57: Result anthropometric analysis The
Page 58 and 59: 6.4 Cognitive ergonomics in wheel l
Page 60 and 61: Discussion operators’ perception
Page 62 and 63: Result of operators’ mental model
Page 64 and 65: Discussion on operators mental mode
Page 67 and 68: 7 Problem definition This is the sy
Page 69 and 70: Table 7.1 Stated needs for handle A
Page 71 and 72: 7.3 Design Heuristics Depending on
Page 73 and 74: 8 Concept generation 1 The first co
Page 76 and 77: 8.2 Concepts The ideas from the ide
Page 78 and 79: 8.3 Concept selection 8.3.1 Concept
Page 81 and 82: 9 Concept generation 2 The second c
Page 83 and 84: Sketches wrist and arm support and
Page 85 and 86: Figure 9.5 Classic joystick Figure
Page 87 and 88: 10 Concept generation 3 When the ba
Page 89 and 90: Table 10.3 Elaboration of physical
Page 91 and 92: Finished functional prototype When
Page 93 and 94: easier to control the functions sim
Page 95 and 96: Housing The housing is as have been
Page 97 and 98: 11 Concept evaluation This chapter
Page 99 and 100: Subjective analysis The participant
Page 101 and 102:
Figure 11.4 Participant E This is a
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11.2.3 Rapid Upper Limb Assessment
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General comments from the evaluatio
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11.3 Conclusion of the evaluation T
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12 Final concept With the input fro
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Table 12.3 Elaboration of physical
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Housing To meet the technical limit
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Finished prototype The prototype re
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Figure 12.5 Angle of handle First p
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Control panel One of the reasons th
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12.5 Final remarks on the concept I
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13 Discussion Different aspects of
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method without reflections on the p
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The choice of consider the 5 th to
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14 Conclusion Discussions about the
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References Literature Adolfsson, Ni
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Figures Figure 1.1, figure 1.2, fig
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Appendix I - HTA HTA of excavating
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HTA of loading logs onto a truck: b
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VI !"#$%&'(()&*#+,-'./'*%,)(0,0&$-'
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VIII Present and Future Yes, but no
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Appendix V - Protocol !"#$#%#&&'()*
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Appendix VI - Questions 14.1.1 Over
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14.1.3 Placement In the fourth and
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14.1.4 Function In the questionnair
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Appendix VII - Result questionnaire
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Design of an ergonomic control lever for wheel loader attachments

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