Internal Geneva Mechanism

1. Aim:

To draw 3D drawings of geneva mechanism from given 2D drawing.

Explanation:

To study about the motion study .We have to consider minimum 2 variables. Motion is consider the change of position of one element with respect to time

Basic priniple-

The use of this geneva cam is transmit rotational motion to intermittent motion

Equations:

The basic equation that helps to this geneva mechanism is ,X =360/n

X is Angle of rotation of the driven wheel or driven part , n is the number of slot in the plate , 360 refers to the one complete rotation of the driving wheel

Procedure:

We take the driving wheel and modify the sketch , along with the projection of pin the a hemisphere type is projected outwards for the arresting of the free rotation of driven wheel. For finding the inward radius , we align the driving wheel and driven wheel together and the centers are aligned horizontal and the centre point of the circle of projected pin of the driving wheel is moved to the slot width of at the extreme in such a way that the outer periphery is touching with the slot starting point. Then the circle which the driven wheel is cuts the driving wheel is marked and make a sketch and provide a outer diameter such a way that difference between the whole diameter of the driving wheel and slot width. For the driven wheel modifying the sketch is by that the given slot is viewed and the centre point of the curved path is marked and a construction circle is made with the full circle centre point. Then we draw a perimeter circle of 3 point circle in such a way that ending point of two successive slot and periphery of the construction circle . Then this arc part is patterned in the 4 slots and then extruded cut to create a driven wheel of geneva mechanism

Mechanism/Working

When the pin in the driving wheel is inserting in the slot the driven plate will tend to rotate . As the pin travels along the slot the intermittent motion is executed.

The reason behind this kind of motion is the pin is forcing to travel in between the pin but the constrained path is allowing the pin to slide along the slot .

When the pin is disengaging from the slot the free rotation of the slotted plate is arrested by the design of the driving wheel in such a way that the contact surface of the driving wheel curved outwards is travel along the curved inwards surface of the driven wheel. This contact will arrest the movement . When the pin is rotates and then engage the slot that after it so the motion continues like that.