Questions tagged [mechanisms]

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38 views

What is the purpose of the ink delivery disks found in most rollerball pens

See picture. In most rollerball pens there are those peculiar looking disks near the nib, the purpose of which I have not yet figured out, apart from being some kind of ink reservoir/flow control. ...
4
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43 views

How do these thread-holder mechanisms work?

In old scientific apparatus for electrical experiments, and more particularly in instruments such as galvanometers and torsion balances, we often need to hold one end of a thread in place. Examples ...
3
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1answer
332 views

Quick return mechanism for spring-loaded screw

Looking for a way to convert rotary motion to linear, but it should take less energy to get back to initial position than when going from initial position to the end position. Specifically, a screw ...
3
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1answer
1k views

Alternative to eccentric spacer nuts

I am using eccentric spacer nuts to create a tight fit between wheels and a rail of a linear sliding mechanism. (Expand the product description in the link to see a picture of it in use). They aren't ...
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1answer
46 views

Automatic compression of springs

I am trying to design something for a friend, but am struggling to come up with the mechanics. Can you help? So imagine a long extendable pole, like a bow staff. Imagine after pulling out a "peg&...
2
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1answer
204 views

How to make a cyclorotor?

I have looked for a way to make a cyclorotor mechanism which allows the blades to rock/rotate (in the picture below, its rocking I believe) to no avail. I am not able to find the required length of ...
2
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0answers
52 views

Rotating four cylinders with one motor/actuator

I have a setup with 4 cylinders placed next to each other in following configuration. The cylinders are made of .2mm stainless steel. I would ideally want to rotate them along their axis using a ...
2
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0answers
590 views

IV drip/flow rate controller design

I have a question about intravenous flow rate controllers, which are controlled using microprocessors. For example: I want to control the IV flow rate, the flow is in range from 0 to 300. So, I just ...
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0answers
306 views

Designing a clamping mechanism for linear sliding stick

the problem I'm prototyping for a musical instrument based on sliding sticks (see https://vimeo.com/170450482) but I'm struggling to make a robust, yet smooth clamping mechanism for the sticks. The ...
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16 views

Velocity and Acceleration Polygons for Mechanism

I need to determine the velocity and acceleration of point H using vector equations and drawing a polygon. Given data is shown. $\omega$2 is 5.8 rad/s and $\phi$2 is 120 degrees I know how I can draw ...
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37 views

Lowest temperature at which a spring powered mechanical wrist or pocket watch will stop operating

In the Wired article 9 Russian Adventurers Mysteriously Froze to Death. A New Theory Explains Why, it is stated that: Without body heat to keep it warm, in such cold weather—estimated to be –13 ...
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35 views

Solenoid with 3mm stroke and ~1ms response time possible?

I need to extend and retract a needle as fast as possible with dwell time while retracted, while one option I really like would be to use Scotch Yoke with dwell. However that would mean the stroke and ...
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25 views

High articulation joints

Looking for advice or suggestions for high articulation joints (>57°) for an automotive halfshaft. Peak operating conditions are in the ballpark of ~1000RPM, ~300ft-lb torque. I've considered u-...
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30 views

Where do I learn about jewel bearings?

I would like to take a deep dive into the world of jewel sourced watchmaking components (including, but not limited to, bearings) but I am having trouble finding any textbooks on the subject. Are ...
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111 views

How does a power hacksaw lift on the forward stroke?

Hacksaw blades cut on the pull stroke (back into the machine) and are supposed to lift on the push stroke, all the DIY setups I have seen cut on both the pull and push stroke, i.e. What type of setup ...
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0answers
70 views

Equivalent moment of inertia in a crank-rocker mechanism

I'm attempting to model a crank-rocker mechanism (see picture). A motor is connected to the crank side and is driving the mechanism with a torque $\tau_{motor}$. A load is attached to the rocker side ...
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0answers
18 views

Clutch for high-speed operation (>40 000 rpm)

I'm currently working on a setup where at some operations my motor has to drive a shaft up to the motor's maximum operating speed (12,000rpm) and a torque of ~0.14Nm but at other conditions this shaft ...
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30 views

Mechanism to alternate between two lifting ends

I'm thinking of what mechanical mechanism can be used to alternate between two different lifting heads, an adhesive and a non-adhesive side, attached to an arm, so that either head comes forward ...
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0answers
103 views

Analytical six-bar linkage trajectory solution

Six-bar linkage is shown on the image: It has one degree of freedom, so if one of the variables is constrained, it's possible to calculate the positions of all the joints. In this specific case the ...
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27 views

Mechanism timed by wheel rotations

I hope this is not off-topic. I’m wondering if someone could please provide some examples of a basic mechanism (I’m thinking something like a bevel/spiral gear, but open to anything) that is attached ...
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0answers
62 views

Why don't we make mainsprings out of Kevlar?

The most important factor for mainspring is, as far as I understand the matter, is their yield point. In this regard, Kevlar beats steel by at least factor of two. So why aren't we using it instead ...
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2k views

Mechanisms to convert linear motion to rotation

These are the mechanisms I'm aware of: Crankshaft Scotch yoke cam-shaft wobble drive (a.k.a nutator or Z-crank) swash-plate What are other mechanisms to convert linear motion to rotation?
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1answer
236 views

Will this straw feeder work?

I'm building a machine to make drinks and I would like to be able to put a straw into the cup. To achieve this, I need to build some kind of mechanism, that will be able to feed me with one straw on ...
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0answers
347 views

Synthesis of 5 bar mechanism

I'm working on my university project but I can't find a proper synthesis method for 5 bar mechanism. I'm working on underactuated mechanism. It's a slider crank with the connecting rod divided into 2 ...
0
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1answer
44 views

Push-to-eject mechanism

I'm currently designing some small-scale robots capable of both melee and laser-tag combat. For the melee component, I'd like to create small, ejectable panels that hide the laser-tag receivers. When ...
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2answers
53 views

How to attach a metal rod to an air cylinder?

I have signed up for an engineering class, and the first project is purely mechanical. I've never done mechanical work, so this is quite interesting to me. I have come up with the following project - ...
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3answers
39 views

Linkage between two vertically and horizontally offset wheels

I'm trying to drive a wheel with a radius of 20cm that is 20cm above the motor and horizontally offset by 20cm from the motor, similar to the following: I wonder what a good linkage might be for a ...
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63 views

Can this SpaceX Starlink ground station antenna's gear mechanism move it in both altitude and azimuth?

Ars Technica's Teardown of “Dishy McFlatface,” the SpaceX Starlink user terminal links to the YouTube video Starlink Teardown: DISHY DESTROYED! and a screenshot from there is shown below. There are ...
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22 views

Help in synthesizing cam profile (oscillating cam and oscillating follower)

I am using Matlab to plot contour of the cam. So far, I understand how to use angular displacement relation between cam and follower to get the profile, pressure angle, torques etc. What I aim to do ...
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20 views

Where to connect the tubes on the refrigerator compressor to operate by using hand?

I am trying to operate the compressor of a refrigerator using my hand. I have opened the case of the refrigerator compressor and removed the part responsible for the compression. I have made a gearbox ...
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0answers
25 views

Mecanum wheels begin to make robot spin around rather than move to the side

I am using mecanum wheels to steer my robot which I am programming using an arduino. The main problem that I am having is that whenever I attempt to make the robot move sideways like this: Instead ...
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0answers
31 views

Retractable cable mechanism

I am working (as a hobbyist) on a motion system where there be electrical cable (multi-core for signaling) going to the moving part. I have considered multiple solutions to connecting the cable to the ...
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2answers
37 views

Looking for feedback on a lift bed power lift mechanism

I built a king size lift bed. I want to add a powered lift mechanism to raise and lower it to access the storage area under it. In order to get the height I want when the bed is raised, I'll need ...
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0answers
26 views

Tiny sliding mechanism

I have been trying to build a sliding keyboard phone attachment for a while now, but can't seem to get anywhere. Basically, I want to combine my Moto Z Play with this cheap, generic bluetooth keyboard....
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48 views

What mechanism do safety belts use to engage?

Earlier today I came across a creep testing machine that uses a safety belt as a mechanism for stopping loads from hitting the ground. It is probably the first time I saw a safety belt roll outside of ...
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0answers
27 views

Can you get the ratchet mechanism out of a socket wrench by itself? Anyone know where if so?

Title pretty much says it all; looking for a reversible ratchet hub for a special latch that I'm designing. Definitely open to any ideas/sources that the community at large might have. Thanks!
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61 views

What type to mechanical joint to achive Slide then Rotation motion

I have two parts (Green and red fixed) i want to connect them with a joint (Blue) that permit the green one to slide outwards then rotate. Side View (Right part) a simple pivot point doesn't work ...
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66 views

Making a machine to sort out old bolts, washers, nuts etc in workshop

I spend a lot of time in my workshop sorting out and putting back into their boxes bunches of screws, washers, nuts and other assorted niknaks and I want to make a machine to take this chore off my ...
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0answers
1k views

Toggle position of a fourbar slider-crank

In the fourbar mechanism as in the following picture, I have to find the toggle position, the sliding distance and the time ratio. Here is my understanding/plan to do this: The toggle positions ("...
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0answers
34 views

Mechanical solution for keeping a vertical stack under pressure

I'm looking for a solution for keeping a vertical stack of small boxes under tension. I will use the device in the attached picture to hold the boxes which will have a lid on the top, and the boxes ...
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0answers
39 views

Is there an easy way to calculate carrier output of a planetary gear set which has two inputs?

Online I found many guides and videos on how to calculate outputs of a planetary gearset but all of them have only one input. But how can I calculate output speed of carrier if ring and sun gear are ...
0
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2answers
123 views

Off-center hinge construction

I want to build a monitor supporting arm for three monitors besides each other. The outer monitors shall be able to swivel forward to reduce size of the whole thing when not in use. My problem's that ...
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3answers
272 views

Polarity of a relative angle - Knee joint angle

I'm wondering if it's correct to write: $$ \alpha = \theta_{lg} - \theta_{th} $$ EDIT: the theta angles are defined positive in counter-clock direcction, instead alpha in clockwise direction. My ...
0
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1answer
84 views

Steering with momentum

I'm thinking of making a RC tank that should be simple as possible. But I'm not sure how to make proper steering for the tank. I googled about tank steering and found (for me) complex solutions as ...
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1answer
304 views

Types of articulation

I am in the process of designing an off road vehicle and require a form of articulation between the front and back half and cannot find relevant information on the types of joints available. I'm ...
0
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1answer
309 views

How can I measure the coefficients of friction of pulleys?

I have to study several industrial pulleys made for lifting heavy weights. It is important to select one which has a low coefficient of friction because the system is based in a hoist and several ...
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1answer
47 views

Design suggestions for Mechanical rotating disc with 30 degrees step

I am a software engineer with no knowledge of mechanical engineering. I need to buy or build a rotating disc which can rotate in 30 degree steps only i.e each time I try to rotate it, it should take ...