Need help to lift up 4 pounds of weight

mpcotuong

Joined Aug 26, 2010
170
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

#12

Joined Nov 30, 2010
18,216
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.

Bernard

Joined Aug 7, 2008
5,720
#12-clever. I was going to suggest a rack & pinion, with pinion having teeth only on one half. Like a small pile driver.

djsfantasi

Joined Apr 11, 2010
7,249
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?

#12

Joined Nov 30, 2010
18,216
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.

KMoffett

Joined Dec 19, 2007
2,918
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

mpcotuong

Joined Aug 26, 2010
170
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

mpcotuong

Joined Aug 26, 2010
170
#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

Bernard

Joined Aug 7, 2008
5,720
' 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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mpcotuong

Joined Aug 26, 2010
170
Hi Bernal,

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

Kevin

Bernard

Joined Aug 7, 2008
5,720
Here is a slightly modified cam that has a constant 1:5 slope.

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Bernard

Joined Aug 7, 2008
5,720
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?

mpcotuong

Joined Aug 26, 2010
170
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

mpcotuong

Joined Aug 26, 2010
170
Hi Bernal,

This is sinngle action once I get trigger.

Thanks,
Minh

mpcotuong

Joined Aug 26, 2010
170
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

Bernard

Joined Aug 7, 2008
5,720
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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mpcotuong

Joined Aug 26, 2010
170
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

Bernard

Joined Aug 7, 2008
5,720
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.

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mpcotuong

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

Kevin

Bernard

Joined Aug 7, 2008
5,720
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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