Abstract:
A rotary mechanism having a single blade mounted on a segmented
ring attached to a main shaft through three spokes was developed. A movable
platform for supporting the coconut and feeding it to the rotating blade was also
developed. The movable platform rested on an auxiliary platform for regulating its
motion. A twin hand-lever arrangement enabled the moving of the movable
platform towards the blade and backwards. Both the mechanisms were mounted
on a machine lathe which formed the test bed. The blade was rotated at a speed of
30 rev/min. The coconut placed on the movable platform was pushed, together
with the movable platform, towards the rotating blade using the twin hand-levers.
The blade pierced the husk on one side of the coconut and ripped open a sector of
the husk. Using the twin hand-levers, the movable platform, together with the
coconut, was then moved backwards. The coconut was turned about its
longitudinal axis enabling to feed another sector of the remaining husk to the
blade. The coconut, together with the movable platform, is again pushed towards
the blade for the blade to detach another sector of the husk. By repeating the
operations, the entire husk was removed. The mean husking durations for 15 each
green and dry coconuts were respectively 24.5 and 26.1 s. The maximum
durations for husking the green and the dry coconuts were respectively 51 and 50
s and the minimum 7 and 12 s respectively. The number of pieces into which the
whole husk of a coconut was split came to 4-6 for the green coconuts and 4-7 for
the dry ones. During the experiments, none of the green coconuts got
mechanically damaged. Though two of the dry coconuts got damaged, one was a
rotten nut. The other was damaged due to non-withdrawal of the coconut after the
separation of the husk-bit from that part. This was hence an avoidable damage. As
a whole, considering its performances, the two mechanisms developed in this
study appeared to be promising. It also requires further improvements.
