Questions tagged [pulleys]

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9 views

Tensiometer Equations

I'm developing a concept for measuring fiberglass strand tension. The basic concept of the machine is that we tension the strands first, and then we measure the tension. In the part where we measure ...
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27 views

using wave motion to raise mass INSIDE a ship?

As a ship bobs up and down, can a pulley INSIDE the ship raise a large mass? ...
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20 views

H-Bot Pulley Assembly - 'Normalizing' Diagonal Movement Speed

Given a traditional H-Bot pulley assembly with 2 stepper motors, how would I calculate the RPM's needed to limit diagonal movement speed to that of comparable horizontal/vertical speed? Would I simply ...
41 views

Steel cable trolley, best practices and weight limits

I asked "AI" to confirm metrics from other sources and it gave numerous formulas and dubious answers, none of which inspired confidence. The goal is to set up a cable system to transport a ...
1 vote
64 views

Will this pulley system work?

I want a system to move something in the opposite direction to the driven thing, but twice the distance. I'm thinking the below system of pulleys. I just wonder if it will actually work or will it ...
33 views

Passive mechanical system to direct force and displacement into different ropes - Can this even be? (Mechanical transistor with direct actuation)

In this question I'd like to ask wether it is possible in general to build the following device. I don't come from an engineering background, so I'm probably not using the right words, but I'll try to ...
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31 views

How are the motors coupled to pulleys in this scara robot?

Several years ago the CoRETS group posted a animated video about a novel SCARA robot https://youtu.be/P3iIIqFkSIc but there are no references to it in the literature. I cannot understand how the two ...
• 273
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Is there a special wrench used to remove this servo tachometer?

I tried using a pulley puller with moderate force to remove the tachometer but it didn’t seem so budge (although I didn’t use heat to soften potential adhesive inside). Looking at the shaft I can see ...
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76 views

High torque timing belt

I'm building an automatic litter box for my kitty and I tried building two versions using a GT2 timing belt + pulley but the belt seems to slip from the pulley often (since it requires high torque) ...
75 views

Would the reduction ratio of a pulley drive also be applied to a compound pulley?

So, a pulley drive with the drive pulley having 1cm of diameter and the driven pulley 10cm of diameter would have something around a 10:1 reduction ratio. However, I don't know if the same logic ...
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1 vote
23 views

Effective Designs for outdoor clothing elevator free from walls

A strange question, but I live in a building (gringo in Mexico City) where the only area you can dry clothes is in a set of chain-link cubes on the roof. However, those cubes are about a story and a ...
106 views

Find transfer function of a drive pulley where the output is a spring force

I have the following system and have deduced the equations of motion to be and with the substitutions for the spring forces we get I understand how to find the transfer function of any single ...
162 views

How A Cord Lock in A Window Unlocks

In this video(https://youtu.be/QvLdVWS_DsM) it says that a cord lock works like this: there is a cylinder which the string moves around, and there is another cylinder which is rough. When you pull out ...
698 views

Can I use this simple pulley system to lift a large 100lb box?

Problem: I have a 98 lb box with dimensions of 45"l x 41"w x 27"h that holds a holiday decoration. I need to lift it to a shelf I made that is 103" above the floor. The space I ...
52 views

How to affix a 3/4" keyed bore wheel/pulley to 5/8" D-profile shaft?

How do I affix a 1.5-inch-thick wheel with a 0.75-inch keyed bore (or pulley) to my motor's 1.25-inch-long x 5/8" diameter D-profile shaft (both pictured)"?
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223 views

What mechanism would you use to lift, then at a certain point release something with a pulley, string & motor

I'd like to lift an inflatable cow up to a pulley I threw over a high branch and then release it to fall when it gets to the top, and then repeat the process. I currently have a loop of string between ...
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61 views

PVC Stripping issue on steel wire with pulley

I am having some issues with a PVC coated steel cable. The PVC often strips when used with a pulley. I wanted to know why this may be happening and possible solutions for it.
54 views

How to solve statically indeterminate pulley?

I am working on a wire rope pulley at rest, shown below. The wire rope wraps once around the pulley (180°) and has tension T. The pulley axle is on a sliding track that is up against its hard stop, ...
123 views

Designing a low-tech, clockwork-like automatic timer via powered winch and pulley system

I'm trying to design a fictional winch and pulley system that, in its basic form, is a weight tied to a rope, that goes through a pulley, which then attaches to a powered winch: the winch turns, winds ...
• 1
31 views

Collecting a released rope with a proper speed

To simplify the problem, I liken the problem to a ship approaching the shore and a device wants to collect the rope in such a way that the rope is neither stretched too much nor released to the extent ...
1 vote
653 views

Pulleys vs gears for a gravity battery

I would like to build a simple homemade gravity battery (a weight is pulled to a high height and is then dropped to turn a motor and generate electricity.) My plan is to have a 5kg weight pulled to 2 ...
305 views

Engineering a pulley system to make an object move when gate is opened

Updated image attached based on @Translators suggestion comment Hi I am looking to make a movable wood cutout via a pulley system on the back my gate/fence (a monkey that tips a top hat when gate is ...
88 views

What's the mechanical advantage of this leg extension machine?

At my local gym there is this leg extension machine and I'm trying to figure out the mechanical advantage. The pulley attached to the disk (marked by red arrow) confuses me because the disk moves when ...
43 views

Does "stacking" of thinner timing pulley and belts reduce "belt stretch", as using a wider belt would?

When wanting precise belt driven motion, it is desirable to reduce belt stretch by using a wider and/or stronger belt. Wider GT family can be quite expensive (hundreds of dollars) compared to thinner ...
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89 views

Can I drive a pulley with two shaded pole motors using one motor at a time with different size pulleys for speed control?

Using two same RPM shaded pole motors, one with a one inch diameter motor and one with a two inch diameter. Using a DTDP switch to swap power from one pulley to the other. For a two speed rotation ...
1 vote
308 views

Would this pulley system only halve the force?

TLDR: Is this only a 2:1 pulley system? Hi there, I’m trying to build a Murphy bed for my roommate. Long story short we’re using an electric hoist + pulley system to raise and lower the bed. The setup ...
143 views

Clutch for rotating axis of mount used for astronomy

a short disclaimer that for me mechanical engineering is a hobby. Please be gentle with me, even if there may be an obvious answer. The main reason for asking here is that searching for the topic you ...
120 views

Modulating Output of a Pulley with Variable Inputs

I am working on a recreational project to take variable inputs and convert them to a constant output without substantially altering the force required to achieve such a task. The best way to visualize ...
99 views

Can you calculate torque without any pulleys involved, and if so, how?

I'm trying to calculate the type of motor I need to turn something of a certain weight, so I feel the thing I'm trying to calculate is torque, but, when I research how to find torque, I find this &...
63 views

I am trying to make a pulley reduction system for my project. I need it to be as quiet as possible, so I am considering pulleys. My project also has limited space, so I am trying to have as small a ...
82 views

XL timing belt missing Dimension!

I'm trying to design and 3d print a XL pulley. I think there is a missing dimension that I can't find in the spec tables. we've got pitch circle, teeth height, belt thickness... but I can't find ...
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106 views

Bushed 3" V-belt pulley with unkeyed 3/4" shaft?

Shortly I will have two 3/4" unkeyed shafts needing 3" type-A V-belt pulleys, one each. They'll each have their own motor driving them, and will need to run to 5000 RPM and possibly higher ...
1 vote
1k views

In an open belt drive, which angle of wrap should be taken for calculating tension in the belt?

An open belt drive with flat belt has different angle of wrap on the larger and smaller pulley. I have to calculate a tension in the pulley. We generally use the formulae Here θ is the angle of wrap. ...
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How can I cheaply tilt a 700 lb cactus?

We got some heavy rain last week and a 4.5 ft tall barrel cactus fell over. Assuming most of it is water, it probably weighs about 700 lb. I've read that if I moisten the soil, take care with the ...
1k views

How can you control the speed of a rope moving through a pulley?

I'm putting together a ceiling-mounted clothes rack. The rack is raised and lowered with rope and pulleys. If the rack is raised under full load and accidentally released, then the system could be ...
47 views

Minimum pulley diameter at small scale

I am trying to design a musical locket which includes a slowly (28 rpm) rotating component. The two things that make this a challenge is: Very limited space. The motor and the reduction system should ...
670 views

I am in the process of building an antenna mast that can tilt from horizontal (down) to vertical (up). The mast (arm) is 360" and weighs a total of 105 lbs. I need to calculate the amount of ...
2k views

Mechanical Advantage of 3 Pulley System

I am a physics teacher, but have found myself teaching engineering. I have come across the following pulley question, and am starting to doubt my own understanding of pulleys ! Until now the rule ...
206 views

Rubik cube torque experiment - Correct equations and experiment set up?

Background I am attempting to experimentally find out the average torque required to rotate a single face of a Rubik cube. Little to no data is available as it varies from cube to cube. Some people ...
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Endless synchronous belt problem

I have a motor coupled over a synchronous belt (AT5) to a bigger tooth wheel (1:4), and the problem comes up that the belt is moving up or down (depending on the rotation direction) until it reaches ...
119 views

What would the tension in the cable be?

A subsequent question stemming from here A massless motor is attached to a massless pulley(the blue circle) with a fixed rotational inertia and they are all attached to a mass X (the green platform). ...
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189 views

HTD3 tooth pulley design

I try to design a HTD3 pulley, but I don't know, how the teeth exactly should look like. I found the following specification: But this seems to be wrong, since I found some HTD3 STL files and ...
3k views

Degrees of Freedom for Complex Pulley Systems

I'm trying to understand DOF clearly, but this pulley system has me doubting myself. When I try to determine the degrees of freedom, I sum the DOF of each object, and subtract the constraints. for ...
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How to pull on one side, while keeping an angle?

I have the following setup, consisting of a bar attached to another bar via a ball joint (indicated by a circle, and attached to the wall over a pulley with a weight at the end (the small "kg&...
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Use of pulleys in gearboxes

I'm designing a simple gearbox with some fairly strict space constraints. I was wondering if having a belt pulley inside of a custom gearbox is a serious issue for the belt. Would it get worn down ...
71 views

Braking movement of a chain through a pulley or sheave

I am attempting to build a rotating climbing ladder, similar to the one below. The structural supports will be different, but the mechanism of chain (or cable) running in a loop over pulleys/sheaves ...
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I'm looking for the simplest way to increase rotational speed from 120 to 5,000 rpm for a light duty device

I'm currently designing a device and want to increase speed from 120 to 5,000 rpm. Device is lightweight, hand operated, free spinning, low torque in/out. Picture a cheap fertilizer spreader from Home ...
1k views

What makes a pulley that is rated for horizontal pulling different from a pulley rated for lifting?

I have a home project that involves lifting a platform with a cable that runs through a series of pulleys to redirect the cable. I'm selecting pulleys for the job and I see that some pulleys are rated ...
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Is there any way to conserve energy for the following scenario of lifting weight?

A pulley can be used to provide mechanical advantage while lifting weight. Suppose a combination pulley is made such that in order to lift something four times heavier, one can use the same force but ...
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