# Need help to lift up 4 pounds of weight

Discussion in 'General Electronics Chat' started by mpcotuong, May 16, 2011.

1. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
0
Hi All,

I have question that if there any motor can lift up 4 pounds and drop it back as free moving of the motor. Any Motor or mechanical suggestion is helpful.

Thanks,
Kevin

2. ### #12 Expert

Nov 30, 2010
16,018
6,532
If you only need a small amount of movement you could have the motor turn a large wheel with a peg inserted at an angle near the outer rim. The peg would be angled upward on the side when the wheel is lifting the weight. Hang the weight on the peg with a string and it will be lifted then dropped as the wheel turns and the angle of the peg changes so the string will slip off the peg.

I apologise if I have not answered you well. You might wish to describe more conditions required of the mechanical assembly to get a better answer.

3. ### Bernard AAC Fanatic!

Aug 7, 2008
4,135
393
#12-clever. I was going to suggest a rack & pinion, with pinion having teeth only on one half. Like a small pile driver.

4. ### djsfantasi AAC Fanatic!

Apr 11, 2010
2,714
791
What is the four pound object you are trying to lift?

How about a linear actuator driving a non-isometric scissors lift mechanism? Or something involving a linear actuator rather than a typical motor that supplies circular motion only?

5. ### #12 Expert

Nov 30, 2010
16,018
6,532
There is also the old ore pounding mechanism where a cam lifts a hammer and loses grip on it at the top of the stroke.

This answer was inspired by bernard mentioning a pile driver.

6. ### KMoffett AAC Fanatic!

Dec 19, 2007
2,558
224
How fast do you have to lift it? A very small motor with the proper gearing can lift a lot of weight...at the cost of speed.

Ken

7. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
0
Thanks, all for your suggestion. Can you please show me the diagram? I need lift 4 pound of object. The Motor move 100rmp at 9VDC.

Kevin

8. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
0
#12 and Bernal,

Please give me diagram and more specific of your suggestion. I need one of your advice for my mechanical lift object and free drop.

Thanks,

Kevin

9. ### Bernard AAC Fanatic!

Aug 7, 2008
4,135
393
' Guess you already have the motor, 9 V , 100 RPM, torque unknown. Length of drop unknown, but it took about 2.5 in. for a 4 lb wt to crack a pecan nut, so will go for 3 in. Might make a rack & pinion with sections of a timing belt. With a hub 1 1/4 in with teeth around 3/4 of circumfrence would give a travel around 3 in. The rack[ straight section ] must be well suported & allow free up- down travel. Radius is a little short of 1 in so motor would need to supply around 64 oz-in or is it in- oz. Main problem is on start of lift for teeth to engage smoothly, thr stop of fall point should be controllable & consistant.
T he cam lift might be easier to build. Using a hinged long arm [ 10 X cam dia. ] with a roller to ride on the cam, would allow lenght of drop to be adjusted.

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10. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
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Hi Bernal,

thanks, so much for your sugguestion. I will try it out. This is good idea for me to try.

Kevin

11. ### Bernard AAC Fanatic!

Aug 7, 2008
4,135
393
Here is a slightly modified cam that has a constant 1:5 slope.

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12. ### Bernard AAC Fanatic!

Aug 7, 2008
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Is this a home work assignment? Did you do any thing with " Lift Handle" or did you just turn in a papper? So now it is 4 lb. lifted to 15 in. with a gear motor of 9V or 12V, turning at 100 RPM, of unknown torque. Single action or repeat cycling?

13. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
0
Hi Bernal,

Yes, this my project. I need to find the component and put them together. Do you have any other way to make and part available?

Kevin

14. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
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Hi Bernal,

This is sinngle action once I get trigger.

Thanks,
Minh

15. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
0
Hi Bernal,

I am not clear about your diagram, so that hard for me to find the part. Can you please detail on the diagram for me? Sorry to ask you again because I am not good on mechanical.

Thanks,
Kevin

16. ### Bernard AAC Fanatic!

Aug 7, 2008
4,135
393
A Confirm height of drop.
B, Time allower for lift?
C, Do you have a motor? Specs.
D, Physical size ol 4 lb. weight?
E, What country are you in?
F, All parts are available in USofAmerica

Here's another choice,; good for about any height

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17. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
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Hi Bernal,

Your picture show that move up. How about drop down without power?

A Confirm height of drop.
AN: 15 inches high

B, Time allower for lift?

AN: The Motor move up when apply power no need time, because I am using 100RPM 9VDC Motor.

C, Do you have a motor? Specs.

AN: 9VDC 100 RPM

D, Physical size ol 4 lb. weight?

AN: yes four pound object weight

E, What country are you in?

AN: US, California

F, All parts are available in USofAmerica

AN: I have only Motor

Here's another choice,; good for about any height

18. ### Bernard AAC Fanatic!

Aug 7, 2008
4,135
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The drawing is a bit crude. When the winch tries to pull the cissors release thru the hole, the wings are forced down, opening the jaws, causing load to free fall. A limit switch, not shown, shuts off motor. A little better view of cissors release shown below.

• ###### Cissors 00000.png
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19. ### mpcotuong Thread Starter Member

Aug 26, 2010
170
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Thanks, Bernal so much. I understand now. Will it still stick with Motor once motor move up again after free drop?

Kevin

20. ### Bernard AAC Fanatic!

Aug 7, 2008
4,135
393
Not sure what " it" is. To repeat cycle- reverse motor or unwinde drum & re-attach weight. Next suggestion might work better & would be easier to make. Rather than going thru a hole, the " claw" can go between two pegs. The claw is a short length of broom handle or 3/4 in dowel, with a 3/8 hole drilled near one end, & then split down the center. The load is attached to a 1/2 length of 1/4 in dowel. The two halvs are held together with two screw eyes & a " washer' , metal, plastic, or plywood. When drum lifts the load, the claw passes between the pegs, and the washer is pushed off, releasing the load & washer, at least in theory.

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