Questions tagged [pulleys]

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35 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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0answers
21 views

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 ...
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1answer
52 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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1answer
44 views

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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0answers
30 views

Exceed 'designed' speed ratio of timing belt

I'm trying to create a setup to transfer motion from a motor to a shaft that requires a much higher torque (bi-directional). The housing is about 6 inches long and the speed ratio needed will be ...
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2answers
28 views

What's a simple machine to lift and drop a 100 lbs weight repeatedly using an electric motor?

Essentially I have a 100 lbs. pile driver with an eyelet for lifting it on top. (It's on rails) I want to set up and automated machine to lift and drop the driver at a variable pace. Preferably I ...
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3answers
38 views

How to make pivoting arms move symmetrically towards each other?

I have a basic design of two arms which need to be brought together. But I tried the design using a test setup and it did not work successfully. Here is a diagram of my design - What I observed is ...
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1answer
27 views

calculation of tension in curved chain for chain fountain (Mould effect)

https://royalsocietypublishing.org/doi/10.1098/rspa.2013.0689 A chain of some sort goes upwards, turns in a half circle (according to the drawn diagram), and goes back down. Focusing on the half ...
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1answer
72 views

Calculating optimal angle on a rolling pulley wheel, which holds weight, on a horizontal cable

The 40 kg load on the rope accelerates from 0 to 50km / h in 6 seconds. The rope is tightened with a force of 500kg while the whole assembly is on it. The middle pulley is driven by a dc motor. I ...
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1answer
44 views

Help me build a mechanical gizmo involving a pulley (I think)

Electrical engineer here. I'm looking to build an incredibly simple mechanism that in my mind involves kind of a pulley. Below is a diagram. So it's essentially like a mechanical servo. I would like ...
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0answers
75 views

How to Calculate the Mechanical Advantage of Parallel Pulleys, and Why?

I am trying to learn about pulleys. I understand why a fixed pulley has a mechanical advantage of 1, as it only changes the direction of motion. Another way to look at it is that the fixed pulley is ...
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0answers
40 views

Springs on a pulley… When to use?

I saw a machine that fed a sheet of laminate through some rollers. The motor had a pulley attached to its shaft, and a spring connected to the pulley. Why not use a belt? Wouldnt the spring make it ...
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1answer
100 views

Minimum required rolling friction between pulley and the rope

The 40 kg weight accelerates and runs on a rope from 0 to 50 km/h in 10 seconds. I want to calculate the minimum required rolling friction that I need (acceleration without slipping) to achieve ...
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1answer
35 views

Trying to visualize the resulting interaction between two pulleys

I'm trying to get an answer for something potentially quite simple, but I can't visualize it (nor do I have the parts yet to build it). It's for a little hobby project, but I'm slightly concerned I ...
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0answers
536 views

How do you calculate the frictional losses in wire ropes over sheaves?

I am currently pulling a load with a wire rope that is moved through a system of sheaves, but had to replace a smaller wire rope cable (1/2") with a larger wire rope cable (3/4"). The sheave/wire ...
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1answer
203 views

How can I couple two small parallel shafts offset a short distance from each other?

I have two parallel shafts, 3 millimetres in diameter and offset by 8 millimetres, both anchored in surrounding housing by ball bearings. When one shaft is rotated (via gear), I want the other shaft ...
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1answer
80 views

Wire type for robotic tendon?

I'm working on a small project where an armature is actuated by a servo via a couple feet of tendon. The servo+tendon needs to be able to pull about 5-10 lbs. There will be springs at the endpoints to ...
2
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1answer
52 views

choosing between v belt and round belt for fast RPM, low torque application

My pulleys are going to be rotated with a 1000-2000 RPM motor, with a constant RPM controlled by a hall effect sensor, there is going to be almost no torque as one of the pulleys just has a 100 gram ...
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3answers
108 views

timing pulleys setup for children's pedal car

I want to convert my son's pedal car to electric. The car is meant for 3-6 year old children. So far I got the following: 50W, 3300 RPM electric motor with 8mm round shaft (no keyway or shaft groove)...
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2answers
768 views

How to mount timing pulleys/belts for small DIY project

I'm building a rotating lamp for a small DIY project to learn about motors and timing belts/pulleys. As I am learning, finding parts that are small enough, fit a stepper motor shaft and reasonable ...
2
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3answers
126 views

Belt tension to rotational force

This may be an obvious question, but here goes anyhow. If you have two pulleys (different diameters) with infinitely strong bearings and shafts, does increasing the belt tension have any effect on ...
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2answers
307 views

Torque Required to Drive Capstan and Bow

I am trying to find the torque exerted on the shaft of a capstan and bow drive. In particular, the system I'm looking at has two wire rope pulleys, and two idler pulleys, and is used to drive a ...
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1answer
94 views

How can i move a 5000 lb object with 1500 pound towing capacity?

I'm getting a shipping container delivered to my property that weighs about 5000 pounds. Once it's delivered I will need to re-position it. I'm thinking of trying to use a number of cylindrical logs, ...
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2answers
93 views

How to fix sheared flats on a pulley?

On my belt sander, there is a small cast aluminum drive pulley/wheel about 1.25" diameter that slips over a 5/16" shaft. Two flats on the shaft mate with two flats inside the bore. The internal flats ...
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2answers
138 views

Surprisingly Low Efficiency of Compound Machine [Project Help]

I'm working on a school project that requires us to build a compound machine with a mechanical advantage of 9. It should be able to lift a 10oz soup can three or more inches by using the weight of ...
2
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1answer
595 views

Mounting a timing pulley on a ball screw shaft

I have a pretty basic question. I need to install a timing pulley on a ball screw shaft (6mm): http://uk.rs-online.com/web/p/products/2816419/ The processed end (the pointy side) of the shaft is ...
2
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2answers
200 views

Pulley system for lifting device [closed]

I'm designing a lifting device powered by a motor, i would like to know if the forces exerted by the load on pulley 1 and 2 are equal when the motor star running , or if in pulley 1 is exerted more ...
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1answer
1k views

Torque and Speed of a DC Motor with Pulleys and Wheels

I want to know how to calculate the speed of an electric skateboard If i have that situation(from the picture below) i will need an acceleration=0.16m/s^2? and a force F~=15N? So i will need a ...
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1answer
273 views

Two-way pulley system considering inertia of pulleys

This is the following question. [![This is how i tried, but I know it is wrong.][2]][2] This is our attempt but We can't seem to solve it with inertia.
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3answers
3k views

Is twisted belt configuration a good practice?

Internet is full of twisted belt examples (30, 60, 90 degrees), however, the allowed misalignment tolerances claimed by the manufacturers are less than several degrees. The very term misalignment ...
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1answer
200 views

How do Cogs and belts work? / Cogs and belts in an ICAS exam

Does the left red wheel turn in the same direction as the leftmost orange wheel?If so P and S go up? If not, Q and S go up? My reasoning: If so Leftmost orange cc Left red cc (by assumption) ...
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2answers
1k views

How to make a pulley system with a mechanical advantage of 0.5 [closed]

Problem Hi I was working for an engineering club and we needed to do this as soon as possible: We wanted to make a pulley system with a mechanical advantage of 0.5 I know that we have to do ...
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1answer
10k views

Difference between a “Pulley” and a “Wheel and axle”

A "Pulley" and a "Wheel and axle" seem much similar to each other. What is their actual difference and what are their precise definitions? My understanding of the two terms is much relied on the ...
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3answers
768 views

Tower crane with a cabin on ground level

Pardon me for kind of a stupid question, but I keep wondering. Traditionally, tower cranes' cabins are located at the top of the tower. I can understand why it have been necessary up to ~1990s, when ...
1
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1answer
728 views

How do I model the friction on a rolling pulley wheel, which holds weight, on a horizontal cable?

I am currently designing a motorized zipline trolley that will carry a person on a horizontal cable, so I am trying to calculate the friction on the wheels to determine what kind of motors I need. I ...
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1answer
470 views

How to design a timer/timing pulley? [closed]

I am asked to design a timing/timer pulley based on a timer belt which comes in standard size. How do I do the calculation to find the number of teeth, depth and width of groove etc?
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1answer
1k views

Rubber Band for Belt in Belt Drive system

Looking to drive a series of belts for lateral translation using a series of pallet bands (92" rubber bands about 1" wide). Approximately 16 bands would be driven by a singular band as illustrated (...
4
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2answers
554 views

comparing backlash of different mechanisms

I have a cylinder with a shaft in its center that I need to rotate at 120 RPM on 180°, for costing reasons, I would like, if possible, to reuse the same DC motor that I already use for another system. ...
8
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1answer
2k views

Dynamics Simple Pulley System - Stuck on the Process

Have spent hours poring over this homework question but am having difficulty getting the right process going to solve the problem. I don't really know where to start, and I'd really be grateful if ...
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3answers
2k views

How can I apply a load to an electric motor to simulate realistic conditions for an experiment?

I am trying to perform some experiments with a motor and I want to run it under realistic conditions (or at least not unloaded). Is there an easy way to load a motor? A couple ideas I had include: ...
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1answer
736 views

Guidelines for motor shaft length and pulley engagement

Searched, but didn't find this discussed here previously. I'm upgrading a hobby-level CNC router (a Shapeoko 3) to have wider belts (it came w/ 6 mm GT2 (2 mm)), I'm going up to 9 mm (otherwise same ...
2
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1answer
126 views

Gear that prevents another gear spinning freely

My Lego model has a winch on the front. It's a simple spindle with a reel on it with a rubberised cog for winding at one end and two cogs at the other (as shown below). Is there a technical name for ...
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2answers
1k views

How to calculate the steps needed for a motor to rotate a circular object in a pulley configuration?

I have a stepper motor with 200 steps per revolution and a pulleys configuration as following: 3 pulleys with 100 mm diameter each on 1184 mm PCD and are equally spaced (120 degrees) from each other. ...
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1answer
2k views

How to design and build a pulley system for a given purpose?

I am a high school student wondering if the pulley system described below will work, and if so, how to go about it. Basically, I have a small system where as you pull back an object, it causes two ...