ch 5 ergonomic in the design of farm tools.pptx

CHAPTER FIVE
ERGONOMICS IN THE DESIGN OF FARM TOOLS
5.1. Design of ergonomics farm tools
• In the past, emphasis was placed on hand tool function :
• to improve efficiency and to allow for standardization,
• to fulfill the task for which it had been designed,
• to respond to the needs of the greatest possible number of users an
• to be as cheap as possible.
Now, in ergonomic hand tool design the basic requirements:
• to improve efficiency and to allow for standardization
• the needs of the greatest possible number of users
• increased comfort and reduced biomechanical solicitation with regard to users’ functional capacities
• cheap in coast

To achieve this, tool manufacturers must take three new types of need into account in the manufacture of hand tools:
- Integration of ergonomics into the design process.
- Definition of the different ergonomic stages involved in the design process.
- Knowledge of the different factors involved in the design of hand tools.
Integrating ergonomics in to the design process
Group of project participants: marketing, design, & manufacturing
Phases :definition of needs, specifications, general & detailed design
To overcome such difficulties, two approaches are to be recommended
1.iterative models, the spiral model for phase organization
2.concurrent engineering for the management of the different protagonists in the process

Definition of the different ergonomic stages in the design process
Knowing the relation between (1) the user, (2) the tool and (3) the workplace, environment and task have led to
reconsideration of the content and meaning of the design process Basic stages in the design process
Stage 1:-Definition of user requirements and expectations
Stage 2:-Design of a new tool prototype based on tool specifications
Stage 3:-Test of prototypes by a large sample of users in real workplace situations

Designing Hand Tools
In the ergonomic design process of hand tools the following
stepshave proved successful:
• target and definition of the design task;
• analysis of the hand tool to be designed;
• development of alternative design solutions;
• evaluation and selection of design alternatives; and
• realization of the selected design solution.

Additionally the following design aspects should be taken into account:
• The visibility towards the working center should be good in any working position.
• Rotating hand tools should –if possible –be designed for both clockwise-rotation and reverse action.
• Feed lines should be fixed symmetrically to the hand tool, so that they cannot hinder the work in one
direction.
Criteria involved in the design of hand tools
Tool mass
Handle form and dimensions
Handle length
Handle material and texture
Protector
Inclination of the tool handle in relation to the functional part of the tool
Other factors
Vibration and reaction torque

User Comfort
Anthropometric considerations
Age
Sex
Experience and technique
Right-and left-handed users
Environmental Factors, Work Tasks and Stations:
The right tool for the job
Position
Physical conditions
Gloves
Tool maintenance
Tool supports and reaction torque bars
Push or pull in the direction of the forearm, with the handle directly in front of it: keep the wrist straight
Provide good coupling between hand and handle by shape and friction
Avoid pressure spots and “pinch points”
Round edges and pad surfaces
Avoid tools that transmit vibration to the hand
Do not operate tools frequently and forcefully by hand; a robot or other machine is better suited for such activities

Handle diameter is large enough for small overlap of thumb and fingers.
Poorly-designed tool: Handle presses into base of palm and requires user to open after each cut (no spring).
Well-designed tool: Handles are long. Spring return keeps tool open. Handles are covered with rubber or plastic grip.

5.2ErgonomicsmachinetoolsDesign
to design tools/systems in terms of the capabilities and limitations of humans is a standardized, formalized, and
comprehensive human factors design process
the activities to be conducted in the determination of requirements and concepts for:
Improvinghumanperformanceandsafetywhilereducingerrorpotential,workloadsandmanninglevels,and
Designing and evaluating human machine interfaces.
Ergonomics machine tools Design process has three main phases:
1.Ergonomics conceptual design process
2.Ergonomics preliminary design process
3.Ergonomics detailed design process
4.Ergonomics test and evaluation process
1.Ergonomics conceptual design process
- Identify and Analyze Missions and Functions
- Conduct Function Allocations and Identify Roles of Humans
- Identify Human Factors Alternate Concepts and Technologies
- Conduct Simulations to Assess Workloads and Human Performance
- Assess Design and Readiness Requirements

2. Ergonomics preliminary design process
Conduct Task Analysis
Conduct of Human Factors Studies
Identify Human-Machine Interface Requirements
•Analyze functional interfaces
•Analyze informational interfaces
•Analyze environmental interfaces
•Analyze operational interfaces
•Analyze organizational interfaces
•Analyze cooperation interfaces
•Analyze cognitive interfaces
Integration of Human-Machine Interface Requirements
Identify Human-Machine Interface Requirements

3. Ergonomics detailed design process
The activities to be conducted in this phase are
Conduct of Human Factors Studies
Define Design Concepts and Criteria for the Design for Operability
Define Design Concepts and Criteria for the Design for Maintainability
Define Design Concepts and Criteria for the Design for Usability
Define Design Concepts and Criteria for the Design for Habitability
Define Design Concepts and Criteria for the Design for Safety
Integrate Human Factors Design Concepts and Criteria

5.3.Ergonomics workstation design
1.Obtain relevant information on the task performance, equipment, working posture and environment through direct
observation, video recording, and/or input from experienced personnel.
2.Identify the appropriate user population and obtain the relevant anthropometric measurements or use the available
statistical data from anthropometric surveys.
3.Determine the range of work height based on the type of the work to be performed. Provide an adjustable chair and a foot
rest for a seated operator and an adjustable Work surface or plat form for a standing operator.
4.Layout the frequently used hand tools, controls, and bins with in the normal reach space. Failing that, they may be placed
within the maximum reach space. Locate Control or handle in the most advantageous position, if strength is required to
operate it.
5.Provide adequate elbow room and clearance at waist level for free movement.
6.Locate the displays with in the normal line of sight.
7.Consider the material and information flow requirements from other functional units or employees.
8.Make as called layout drawing of the proposed workstation to check the placement of individual components.
9.Develop a mock-up of the design and conduct trials with live subjects to as certain operator-workstation fit. Obtain
feedback from the interest groups.
10.Construct a prototype workstation based on the final design.

The four essential design dimensions are:
1.work height,
2.normal and maximum reaches,
3.lateral clearance, and
4.Angle of vision and eye height.
end

ch 5 ergonomic in the design of farm tools.pptx

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