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shiladityachattrrjee54
01-08-2011, 09:27 PM
Can anyone suggest some kind of a digging mechanism which will be fast and efficient for digging sands? accuracy is not a concern.....but the mechanism should be easy 2 fabricate and efficient

vikas
01-09-2011, 01:55 AM
Give more specs (depth , hardness , why dig,payload ) or point to competition link if its for a competition.

shiladityachattrrjee54
01-09-2011, 10:21 PM
well its for kshitij 2011 ............Pirate Bay........nd d depth is about 7 cm........nd its about pickin up a wooden coil after digging through the sand.............

vikas
01-10-2011, 10:30 AM
link ?
Always post link when asking for help about such competitions ...

shiladityachattrrjee54
01-10-2011, 10:47 AM
http://www.robotix.in/events/pirate_bay ......... sorry for the inconvinience

vikas
01-10-2011, 08:41 PM
Something like this or similar mechanism would easily crack this competition -

http://www.youtube.com/watch?v=ZwDHgERW5xk

Only modification would be to make the digger not flat but at an incline pointing towards the ground. and drill pebble sized holes ( 3cm in diameter ) in the loading tray.

shiladityachattrrjee54
01-10-2011, 09:41 PM
Oh okay.....any other suggestions????? i was thinking of sticking propellers in the front to skim out the sand and then use a picking mechanism to pick d coins...........

vikas
01-10-2011, 09:49 PM
Do it the way professionals do it ... its that simple . Build a loader and you can easily crack all three stages . Inead of the front bucket construct a iron mesh based one with max diagonal 3 cm of each connecting square ... it would quickly sort the material.

Dont mind but ...
Have you ever seen any digging equipment using propellers ? i highly dought it ... and i highly dought it would work ... even roughly imaging it i can see too many problems. Do some rough trials and u will see the problems.

shiladityachattrrjee54
01-10-2011, 10:10 PM
Yesss.... infact i hav seen one mechanism which has a rolling drum in d front with slats which churns out the sand........i have done several trials of that with propellers ..it seems to work.....but only problem being that i cannot control d sand throw......... besides can u suggest any picking mechanism for lifting the coin?????

akshay66
01-13-2011, 11:06 AM
Do the way vikas has suggested. It is highly reliable,you might have done various trials but anything can happen what if the sand in the arena is not similar and your propeller jams.

For coins you can use electromagnets.

shiladityachattrrjee54
01-13-2011, 11:40 AM
Yes I am working on that.............. and the coins are wooden so electromagnets would not work...........

lastRites
01-14-2011, 09:21 AM
Is not making a excavator like the one in the video quite complex?? I am making one like:

http://http://www.uploadgeek.com/share-EFA8_4D2FBC58.html

http://www.uploadgeek.com/thumb-EFA8_4D2FBC58.jpg (http://www.uploadgeek.com/share-EFA8_4D2FBC58.html)

shiladityachattrrjee54
01-14-2011, 09:47 AM
No, infact it is very easy.......... use hydraulics for d bucket and you can precisely control the motion.......

when it comes to hydraulics.... be creative.....for queries regarding hydraulics keep me posted,

Be Creative................

robosoftsystems
01-14-2011, 12:48 PM
Hi shiladitya,

I have read the requirement, and there are quite a few interesting suggestions floated by ppl.
How I would picture the whole design is to make the control easy and drive mechanism simple for the user. This reduces lots of hassle, and allows you to concentrate on the task on hand.

Have a look at this video.
http://www.youtube.com/watch?v=0oo4wGVwLy4&feature=related

How I would picture you incepting your design is something like this.
Design the Loader vessel such that its open entry end is facing outwards, unlike the one in the design. This would enable you to stay clear of the land that you unearth, thereby avoiding toppling of the flags accidentally.
For precise control of the loader mechanism, make use of servo motor. You can either use a microcontroller board to control the whole machine (all the motors), or make use of timer circuit to control the servo. If you want to avoid using servo, make use of a low RPM DC motor.

Design the Loader vessel with a hexagonal mesh (hexagon side dimension >=19 mm). This would allow you to filter the sand/pebbles, thus uncovering the coin.

Last and a very important aspect of the design, make use of a vibrator motor attached to the Loader vessel. This would enable you to vessel through sand/pebbles on the go thereby retaining the coins in the vessel. Ensure that the dimensions of the loader is justifying (big enough so as not to miss/displace the coin while digging and small enough to maneuver without toppling things around).

Best of luck!! :cool:

Regards,
Rohan Soni
(Robosoft Systems)

shiladityachattrrjee54
01-14-2011, 01:17 PM
I have seen and studied the moon digger bot whose video uou have posted. Yes infact i am doing that. But i am buliding a classical shovel but for precise control i am using hydraulics. also yes i am doing holes in the loading bucket for filtering the sand.
for hydraulics i am using normal injection syringes whch are paired via saline pipe . the injection is pushed by a motor with a worm gear and a spur gear assembly to transfer perpendicular motion.

Thank You.

Regards,
Shiladitya