The document describes a team's design of an improved knapsack sprayer that uses leg movement rather than hand pumping to pressurize pesticides. Their concept uses links connected to the leg to activate a piston during natural walking. Challenges included allowing multi-directional leg movement, which they addressed with a universal joint. Simulations and testing showed the leg-powered design pressurized pesticides faster and with less effort than traditional hand pumping.
2. Description
• Knapsack sprayer is a device which is used for
spraying pesticides over crops or plants.
• This protects the crop from insects attacks.
• The pesticide inside
the tank is pressurized
using hand power and
rushed out through the
hand held nozzle.
3. Our Concept/Motivation
• Using hand power to pressurise liquid is
strenuous, so we have decided to change the
way in which fluid is pressurised.
• Using the movement of leg to pressurise the
fluid.
• Links will be connected to the leg of the user.
The natural walking of the user would activate
the piston.
4. User Voice…
• The device should work in different
agricultural fields.
• While implementing the idea, the mechanism
should not obstruct movement of the user.
• It should be easy to operate.
5. Challenges Faced
• Initially our design had only one DOF which
resulted in restricted movement. So to
accommodate leg movement in other direction
we used universal joint.
• Links dimensions selection – Various dimensions
can be used for the purpose but which works
ergonomically was chosen after analysis.
7. Link Dimension Selections
S.No Link 1 Link 2
Angle
swept by
link 1
Stroke length
1 395 230 39.92 40.37
2 400 250 35 35.237
3 420 250 32.59 32.72
4 420 280 31.51 31.061 • All dimensions are in mm
Leg
Link 1
Link 2
Fixed Link
Considerations:
• The angle swept by leg with respect to hip is 35o
8. Simulation
• A New improved mechanism is made, which gives
the stroke length of 3.5 cm (approx)
Piston
Travel
directions
9. Analysis 1
•Test 1: The sprayer was pressurized to maximum
pressure using both the hand and leg, and the time
take to spray 100ml of liquid was calculated.
Mechanism Hand Leg
Time Taken
(in seconds)
4.86 4.395
10. Analysis 2
•Test 2: The sprayer was pressurized with 5 strokes
from null pressure in both the mechanism and the
volume of pesticide sprayed was measured.
Mechanism Hand Leg
Volume of pesticide
sprayed (in ml)
320 250
11. Future-Scope
• Variable links sizes can be implemented for
people of various heights.
• Variable nozzle tube length for covering longer
distance can be implemented.
• Pressure relief valve for relieving the excess
pressure developed based on the users
comfort can be implemented.
• Betterment of the leg holder for comfortable
and effective transformation of the force.
12. Conclusion
•The device is designed in such a way that it
works in different of agricultural fields.
•The mechanism designed is not obstructing the
movement of the user.
•No extra effort is required for using the sprayer,
so it is easy to operate.
