To design a mechanism which can replace the traditional hammering mechanism to crush the stones, and to improve the efficiency of worker and reduce effort while hammering the stones.
Parts and materials
Cam - Ductile cast iron
Links - Hot rolled plain carbon steel
Support shafts - Ductile cast iron
Hammer head - Medium carbon steel
Cam support and Link support - Ductile cast iron
Constraint on Design 1
If mass of the hammer is increased, then we don’t need to lift it to the same height to create same impulse, so we can have smaller link lengths. But at the same time, we will be having problems for feeding the rock in and also input torque increases.
Constraint on design 2
If we increase the length of the link 1, we don’t need to turn it too much about pivot to raise it to the same height, but at the same time we need to apply more torque to rotate the mass. Link length and torque are linearly related.
Constraint on design 3
If we change the pivot position, all the assembly will get affected. Hammer may not rise to the complete height required or it may rise more than required, some components may get stuck while moving. So we need exact position for pivot for good impulse generation.
Constraint on design 4
Rotation angle at pivot is also very important. If it is too large, cam size will increase dramatically and there will be a lot of torque variations while
rotating cam. If it is too small, we need to have large links thus by increasing torques.
Constraint on design 5
If length of second link (one which is in contact with cam) is more, we will need larger cam and if it is too small larger forces will be generated at cam and link contact which damages components.
Constraint on design 6
If cam base radius is too small, pressure angle will be high, which causes more stress at cam bearing contact. If it is too large we will need a lot of material which increases the cost of assembly. Also if we have large mass, we will need to put in more energy to start or stop the mechanism (It acts like flywheel)
Scope of Improvement 1
Design of Cam: Improved design of cam to make the forces involved in lifting the hammer head constant
Scope of improvement 2
Productivity: Productivity can be increased by increasing the size of product so that it can accommodate more number of cams and hammer heads to increase the number of stones crushing at an instant
Scope of improvement 3
Feeding Mechanism: Implementing the feeding mechanism (As shown in CAD model)
Suggestions and critics 1
Multiple use of product with modification in design by replacing hammer with axe for wood cutting.
Suggestions and critics 2
Manufacturing could have been done in better way.
Suggestions and critics 3
Attachment of Cam to shaft could have been done through a key rather
Suggestions and critics 4
Integration with Hu‐motor and incorporating feeding mechanism.
1. youtube.com/watch?v=gD6d4hyLNNs 2. MachineDesignbyRobertL.Norton 3. efunda.com/materials/alloys/alloy_home/steels_properties.cfm