Jump to content


Lego Technic Grab / Claw / Gripper


44 replies to this topic

#1 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 12 February 2012 - 07:59 PM

Hey there every one.

I am trying to find the best design for a small but strong Grab / Claw / Gripper to use with my Lego robotic arm project. I have found three suitable designs and I have built and pictured them.

Posted Image

This grab was designed by Leo Dorst this design is very special as it is symmetrical both sides of the grab open and close the exact same way (Taking in to account the play between the gears) . I have made minimal changes to this design just changed the size for the grab arms and added rubber tips to them. This design is also not centred around the drive axle and would not be easily connected to a turntable.

Posted Image

This grab was designed by Leo Dorst this design is very special as it is symmetrical both sides of the grab open and close the exact same way (Taking in to account the play between the gears) . I have made minimal changes to this design just changed the size for the grab arms and added rubber tips to them. This design can easily be connected to a large turntable.

Posted Image

This design is very closely based on a grabber made By Eric Sophie over at MOCpages.com. I have just fine tuned the design removing some unnecessary parts as well as replacing larger parts with smaller ones. The grab its now suited to fit with the new small lego turntable. This design does not open or close symmetrically.


I am very interested in your idea's and your comments.

Thanks

Firky.

#2 jorgeopesi

jorgeopesi

    Posts: 1592
    Joined: 30-May 10
    Member: 11011
    Country: Spain

Posted 12 February 2012 - 08:11 PM

Great designs!.
Lego Ideas F40 https://ideas.lego.com/projects/79365
Posted Image Just 380 to get 1000

My brickshelf http://www.brickshel...gi?m=jorgeopesi

#3 timslegos

timslegos

    Posts: 2225
    Joined: 14-July 11
    Member: 19027
    Country: United States

Posted 12 February 2012 - 09:02 PM

nice designs, i will definitely bookmark this.  Those claws could be very useful!

tim

#4 BobBongo1895

BobBongo1895

    Posts: 165
    Joined: 08-January 12
    Member: 23939
    Country: Germany

Posted 12 February 2012 - 09:54 PM

Yeah, the third one is my fav.
Posted Image

#5 DLuders

DLuders

  • Technic Technician


    Posts: 5817
    Joined: 17-October 09
    Member: 7868
    Country: USA (WA State)

Posted 13 February 2012 - 02:06 AM

@ Firky:  All of your designs look very useful.  :classic:   Are you planning on mating the claws onto a Lego 99009 + 99010 mini Technic Turntable, to enable it to rotate on the end of a robotic arm?

Posted Image  Posted Image  Posted Image

#6 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 13 February 2012 - 08:16 PM

Thanks for your kind words however,

I'm not really sure how or when you can claim a design as your own. I just wanted to be clear that these designs were originally designed by Eric Sophie and Leo Dorst and then modified by me to suit my needs. If the changes made now make this version my design then so be it.

@ DLuders: Indeed I do its suited to fit perfectly with a mini Lego technic turntable. The drive axle is dead centre and will fit though the middle of the turntable two 4L axles will hold the turntable in place. I currently don't have a Mini turntable but its in the post on its way here.

Posted Image

Posted Image

Posted Image

#7 timslegos

timslegos

    Posts: 2225
    Joined: 14-July 11
    Member: 19027
    Country: United States

Posted 13 February 2012 - 09:36 PM

I dont think that will fit into the turntable because the turntable's holes that the beems go in would hit the gear  :sceptic: .

tim

#8 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 13 February 2012 - 11:06 PM

@ Tim:  Hi Tim Thanks for concern. I have taken a number of pictures to help show how the mini turntable will fit using parts that are the close match to the turntable its self.

Posted Image

This picture hows how the two connecting 1L lift arms on the turntable will connect to the grab. (grab is in open position)

Posted Image

This picture hows how the two connecting 1L lift arms on the turntable will connect to the grab. (grab is in closed position)

Posted Image

This picture hows how the two connecting 1L lift arms on the turntable allowing enough room for the Axle to fit through.

Posted Image

This picture hows how the 28 tooth gear (I only have a 24 tooth gear in the picture) on the turntable fit against to the grab. (grab is in closed position)

Posted Image

This picture hows how the 28 tooth gear (I only have a 24 tooth gear in the picture) on the turntable fit against to the grab. (grab is in open position)

Posted Image

This picture hows how the 28 tooth gear (I only have a 24 tooth gear in the picture) on the turntable fit against the grab. (grab is in open position)


I hope these pictures clear things up.

Firky

#9 timslegos

timslegos

    Posts: 2225
    Joined: 14-July 11
    Member: 19027
    Country: United States

Posted 13 February 2012 - 11:13 PM

Ohh okay.  I though that the yellow connector would hit the gear.

tim

#10 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 19 February 2012 - 12:42 PM

I am still awaiting the arrival of the Mini lego turntable so I decided to work with one of the other grabs in the mean time.

Posted Image

Posted Image

#11 _techniclego55_

_techniclego55_

    Posts: 151
    Joined: 04-February 12
    Member: 25588
    Country: Austria

Posted 26 February 2012 - 03:17 PM

Nice Work  :thumbup:

#12 parda

parda

    Posts: 210
    Joined: 28-November 10
    Member: 14424
    Country: Spain

Posted 26 February 2012 - 05:43 PM

Fantastic work on these claws  :sweet:

#13 Burf2000

Burf2000

    Posts: 982
    Joined: 08-July 09
    Member: 6615
    Country: England

Posted 28 February 2012 - 02:02 PM

Now this is an interesting topic, some great designs and 1 area I need to improve on!

#14 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 28 February 2012 - 07:30 PM

Thanks Guys. I really wish the micro motor was easier to mount. by they time I've built a mount to secure the motor in place the M motor is smaller and much stronger.

#15 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 22 September 2012 - 10:25 AM

Hey guys,

Its been a while. So since my last posts I did receive my 28 tooth mini turntable and I have fitted it to the grab.

Posted Image

Posted Image

How ever since its a 28 tooth and not a 24 tooth mounting gears for the rotation of the turntable isn't easy. The only gears that fit are the double bevelled gears  as shown below, and with the orataition shown below the axle from the double bevelled gear blocks the thought hole in the trun table that would be used for the grab drive.

Posted Image

Here you can see where the grab drive would go

Posted Image

Here you can see that the axle used for the double bevelled gear blocks the hole.

Posted Image


So guys Im after your help? whats the best way to work with the mini turn table?

Thanks

Firky

#16 Carsten Svendsen

Carsten Svendsen

    Posts: 317
    Joined: 05-September 12
    Member: 31347
    Country: Denmark

Posted 22 September 2012 - 10:47 AM

Couldn't you just align the bewel gear with the turntable so that you have 2 protruding axles from the grabber?
My current project: Antonov AN-140 which is a 1:15,65 scaled airplane

#17 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 22 September 2012 - 12:34 PM

Sadly the 28 tooth turntable does not fit with the gears as easily as the 20 tooth and the 12 tooth.

Posted Image

#18 Carsten Svendsen

Carsten Svendsen

    Posts: 317
    Joined: 05-September 12
    Member: 31347
    Country: Denmark

Posted 22 September 2012 - 01:06 PM

View PostFirky, on 22 September 2012 - 12:34 PM, said:

Sadly the 28 tooth turntable does not fit with the gears as easily as the 20 tooth and the 12 tooth.

Posted Image
That could be solved with half a stud offset.

Posted Image

Edited by Carsten Svendsen, 22 September 2012 - 01:07 PM.

My current project: Antonov AN-140 which is a 1:15,65 scaled airplane

#19 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 22 September 2012 - 01:59 PM

Im sure I tried that before. maybe i didn't off set it tho. ill try it again and see how it goes.

Thanks Firky

#20 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 22 September 2012 - 02:07 PM

Two min's while I make something............:laugh:

Edited by Alasdair Ryan, 22 September 2012 - 02:07 PM.

Posted Image

Updated 02/08/12
Posted Image

#21 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 22 September 2012 - 02:38 PM

waits intently :)

#22 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 22 September 2012 - 02:57 PM

Will this help you?:blush:

Posted Image

Edited by Alasdair Ryan, 22 September 2012 - 02:58 PM.

Posted Image

Updated 02/08/12
Posted Image

#23 Firky

Firky

    Posts: 38
    Joined: 29-January 12
    Member: 25209
    Country: Scotland

Posted 22 September 2012 - 03:03 PM

It would most definitely work. However it's on the big side. Using the 20 tooth gear with the small turn table kinda defects the purpose of using the small turntable as its almost as big as the standard turntable. Sadly I don't have enough parts today to try the offsetting. Using the 12 tooth gear with an offset seems to be the best choice so far.

Thanks for trying :)

Firky

Edited by Firky, 22 September 2012 - 03:12 PM.


#24 Alasdair Ryan

Alasdair Ryan

  • Technic Hall of Fame Editor


    Posts: 5453
    Joined: 22-November 09
    Member: 8292
    Country: Scotland

Posted 22 September 2012 - 03:16 PM

The problem with having a 1/2 stud off set is that is not very easy to brace.
Posted Image

Updated 02/08/12
Posted Image

#25 Zblj

Zblj

    Posts: 4515
    Joined: 16-August 09
    Member: 7054
    Country: Slovenia

Posted 22 September 2012 - 03:28 PM

Guys, do it like this:

Posted Image

Also its a higher gear ratio this way.



Reply to this topic



  


0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users