Need help choosing a gripper

[lcab]

 I am new at building robots and the first robot that I will help build will be for a student competition. I was wondering if anybody knows what would be a good griper to pick up rod that is 8 inches long and not quite sure of its actually weight but it probably weighs around a quarter of a pound. I have looked around at many grippers, but I have not found one that I could use. Thank you.

[little-c]

is it magnetic? then you could cheat and use a electromagnet.

http://www.igg.org.uk/gansg/12-linind/foundry/scrapgrab1.jpg shows a gripper that might work. may need a bit of addaption, but should be fine.

[hopslink]

See the gripper on Admin's ERP . That looks to be a good design for holding tube. If you have to pick up from the floor then you could modify the design towards two straight forklift style prongs on the base with opposing lock.

[lcab]

thanks for everybody's help i appreciate it a lot , i think i will have to design it.I saw this one design on here where they put a servo on a straight piece of metal arm that came out a body, how would i approach this situation because i can't find that page where i saw it.

[lcab]

i have designed a arm and having a little trouble picking the right servo, i found this servo the HSR-5498SG, i need to lift the arm that is going to weight around a pound in the worse case scenario but i don't know if this servo is to powerful and will toss the rod off the arm on our robot. could somebody plz tell me what to look for in a servo and tell me of the servo i have found would be right lifting something around a pound.

[little-c]

power isn't an issue. if its too fast, just write some code that changes its position slowly.

servo will cope with a short arm. worse case it just wants to move a gear that moves the arm.

Id say its over speced, but its a very good servo.

[little-c]

data sheet for the servo, for all who are intrested,

http://www.robotshop.ca/PDF/hitec-hsr-5498sg-digital-servo-specsheet.pdf


this is a cheeper version, HSR-8498HB which is the same servo, just plastic gears.

[lcab]

if i need to transport that object that weighted around a pound through a course could i hold up that weight which could be like for a minute without causing damage to the servo ? thanks for all the help that everybody has given me.

[little-c]

hours, to be honest. depends on battery life. if it runs out of jucie, the servo is just going to switch off.

more likely to have a dodgy mounting bracket shear than the servo break. and you will know if the servo is overloaded. it doesn't sound good.