Need help to lift up 4 pounds of weight

Bernard

Joined Aug 7, 2008
5,717
Just had to try it out. Used 3 in of paint roller handle, 7/8 in dia, with 3/8 hole, 5/8 in from end. Split the rod with table saw, was slightly off center but no problem with operation. Tapered top slightly so that it would not snag on the pegs, also added a grouve in end to allow clearance of cord. Made a loop with bowline knot , placed 1/4 in rod in loop, then rod in 3/8 hole, slipped washer over end. 4 lb brick tied to other end of looped cord. Another looped cord went thru screweyes to lift assembly up thru two pegs, spaced 1 in apart. When pegs hit washer, washer came off, halvs split, brick fell free, crushing a wallnut. Washer is 1/16 in plastic[ ABS?], 3 in OD, 7/8 ID. My name is Bernard.
 

Bernard

Joined Aug 7, 2008
5,717
Congratulations-' see that you are now a senior member. It's not advisable to post E-mail addresses on open forums, lots of viewers; but you can send a private message by clicking on name.
 

Bernard

Joined Aug 7, 2008
5,717
Here is a tested ckt for your weight dropper, including a low battery warning red LED. A pos. going signal greater than 1.233 V resets C555, low output, P3, turns on P-Ch FET, energising Motor & rotary solenoid. Solenoid moves motor to engage winch gear. When winch line is at max lift , knot on line engages SW, which sets C555, stopping motor, weight free falls.
 

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mpcotuong,

This is a very simple design but it gives you several variables for set up operation. The picture doesn't have much detail because the scan file size was exceeding the upload limit.

1 - The ratio of the the pulley size on your motor to the main drive pulley can control speed.

2 - The radius of the main raising pin can combined with the length of the beam length to the centre of the drive pulley control the lift time to allow you to set up the next object for the weight to drop on.

3 - The length of the beam from the pivot to your weight can determine the speed of the final impact of the weight.

By simplicity of design the construction only has to be sturdy and not rugged. A wooden V pulley easily made on a lathe and a V pulley for the motor with a double turn of cord for extra friction should be fine for a drive mechanism. The raising pin can be a 1/4-20 bolt attached through a hole in the pulley with 1/4-20 coupler on the outside to raise the beam. This is not a heavy duty application.

Rectangular tubing is fine for the beam. You can notch the bottom of the tubing to get the right lengths of the beams from the pivot before drilling a hole in the beam for final pivot set up.

Danny
 

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Kevin,

Can you please explain by what you mean "free moving". I interpret that as having your weight fall in a free fall, unrestrained to get maximum force or are you talking about something that works like a punch press in a straight vertical motion, but still tied into the drive motor?

Danny
 

Bernard

Joined Aug 7, 2008
5,717
Danny; Lift up 4 lb, 15 in and let it free fall- repeat 20 times per day for one year; recharge battery every month. Must fit inside 7X10X15 in. box. For what purpose- unknown.
 

Bernard

Joined Aug 7, 2008
5,717
I forgot another bit of information; lift should tate less than 20 sec. Data is scattered over several different subjects. I believe mpcotuong will test a prototype Saturday or Monday, wish him luck.
 
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