Questions tagged [mechanisms]

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1answer
35 views

Looking for locking “lanyard” reel mechanism

I'm working on a system that requires a small cord (~3ft long) to retract up into a reel and lock in place so it cannot be pulled away from the reel. Sort of like a seatbelt mechanism after it's been ...
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 ...
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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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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 ...
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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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2answers
57 views

Bi-directional gearbox

I want to design and create a gearbox that allows an input shaft to be continuously rotating in one direction, while the output shaft rotates one full turn in the same direction but then half a turn ...
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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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0answers
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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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 ...
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3answers
36 views

static friction of gear pair

Im working on a project that has gearing system integrated. From my simulation results im dealing with a relatively small amount of input force at the gearbox and would like to know if the force would ...
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 ...
1
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3answers
178 views

How to design a coaxial 1:2 gear without reversing direction?

I am trying to design a gear that has a 1:2 speed ratio (input:output). This design is very limited in space and for simplicity and space savings requires the input and output shafts to be coaxial. ...
2
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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&...
1
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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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2answers
52 views

Is a pneumatic cylinder in general a linear or rotary actuator?

I've just begun to learn pneumatics and I'm really confused where the pneumatic cylinder falls under in the categorization of what kind of mechanical motion it is suppose to produce. I've seen one ...
2
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1answer
56 views

How might a clockwork mechanism be built, to behave in a pseudo-random or chaotic way?

My brother asked me how I might build a functioning alethiometer, which is a fictional device superficially resembling an analog pocket watch, but with essentially random movements. I told him I would ...
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1answer
34 views

Want to simulate a mechanism with spring in it for forces acting in different direction (Kinematics). How to do it using solidworks or ANSYS? [closed]

Thought of using motion study in Solidworks but not able to account for forces at the different axis in it here is the image to better understand it. There hasn't been any progress with the ...
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2answers
149 views

vertical rack and pinion self-stopping

There are many places I see a knob used to set the vertical position of an object (like in a microscope stand), but how does it not just simply slide down due to gravity once the knob is released. It'...
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0answers
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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1answer
29 views

Sprokets on rotating body

Sorry I'm having a migrane and can't think rn, which is why I am posting such a basic question for confirmation... The above diagram shows two sprockets on a beam which is attached to a driven gear. ...
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0answers
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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0answers
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 ...
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 ...
2
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2answers
205 views

When designing scissors, how do you design the blade geometry to ensure good cutting capabilities?

I have been looking online and found there should be two points of contact, one in the blades and one in the pin. In order to achieve this, I assume there's a slight angle of the blades into the ...
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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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1answer
116 views

Determine the angular velocity and angular acceleration of the AB bar at the instant shown

Consider a sliding cursor C that is fixed to the disk which has a constant angular velocity counterclockwise at 4 rad/s. Determine the angular velocity and angular acceleration of the AB bar at the ...
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2answers
426 views

Right angle gearbox, proper name or design

I'm looking for right angle gearbox, but everything is horrible expensive or in parts like two bevel gears from aliexpress. Where I can find or how to name transmission like this in the picture but in ...
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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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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
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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0answers
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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0answers
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. ...
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2answers
61 views

Multiturn rotational limit switches

I would like to automate a door lock. For reasons I won't get into, I'm not allowed to modify the lock itself, I can only attach things to the "safe side" of the door. On this safe side, ...
2
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1answer
58 views

How to prevent movement in this 3 DOF setup?

I have a 3DOF platform that I'm trying to make more stable. It's difficult to explain in words what the issue is so I've added a GIF below. Any ideas of how I can get rid of this wobble? The DOF arm ...
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0answers
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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2answers
49 views

Do you know any mechanism that can pass a thread through several holes?

Well i am stuck trying to figure out this problem, actulally i see a machine that can make it with a torus, a torus coilling machine. But that not work with a multi turus shape. I want to automate ...
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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....
1
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1answer
195 views

How to couple two pistons to a rotating shaft so that the piston heads move like this?

Assume two vertical pistons with their flat head facing upward. Is it possible to couple them to one rotating shaft in a way that the position vs. time diagram gets like this? (This is one complete ...
3
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1answer
38 views

Controlling torque required to turn a shaft

I have an shaft/crank that will be turned by the user. I want to precisely and dynamically control the torque required to do so. For simplicity we can think of it as a exercise machine (so the torque ...
2
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1answer
51 views

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&...
1
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3answers
80 views

calculating the minimum force needed to lift a rigid awning - class 3 lever problem

I am building a camper and one idea is to have an extra 4 solar panels as an awning bolted to a a rigid frame, hinged to the camper at the top. It hangs down the side of the camper. I will use one ...
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0answers
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!
3
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2answers
121 views

How high will a flywheel catapult launch a payload?

First off, this is not a homework question or anything like that. I'm trying to build a catapult to launch a payload using a flywheel as an energy device! It goes like this: The flywheel spins up to ...
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2answers
107 views

Mechanism for indicating the direction of a shaft's rotation

I have a shaft, which will change its direction of rotation somewhat randomly in response to external disturbances, without a ton of speed/torque. I need to figure out a mechanism I can use to actuate ...
1
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0answers
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-...
3
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4answers
128 views

Rotation around an axis outside of the mechanism

I want to design a system of linkages that will allow me to rotate the green element around the blue point/axis without entering the red circle. The green triangle to go fully around the blue point. I ...
0
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0answers
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 ...
3
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3answers
246 views

Mechanism for controlling the clamping force

I am working on upgrading a research project on wind energy. They are trying to measure the performance of wind blade designs in a small wind tunnel (i.e. their models are relatively small). What they ...
2
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2answers
45 views

What is a constricting actuator called?

I'm looking for search terms, I'd like to find something like an electric hose clamp - a high-force, low-power, low-speed, motorized constricting mechanism. I already googled some terms various ...