Questions tagged [mechanisms]

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14
votes
3answers
7k views

How do bike wheels keep turning when the rider stops pedalling?

I am very confused with something regarding bikes... How is it that a bike wheel continues to spin (either from momentum or from going downhill) when the rider is not pedalling, without also spinning ...
6
votes
2answers
3k views

Is there a mechanism that can turn circular motion into alternating circular motion?

I'm trying to power and agitator (alternating circularly back and fourth) with a crank. I've seen a bunch of complicated mechanisms that do this, but I'm looking for the mechanically simplest method.
6
votes
1answer
39 views

How is mechanism used in modern projector different from intermittent mechanism used in conventional one?

Do modern projector used for digital class works on same old conventional intermittent mechanism and blocking of light during change of frame. What is principal used in modern projector?
6
votes
1answer
451 views

What is this kind of bearing called

I came up with this concept for a partial rotation, lubricant free, low friction bearing for a robotics application. Two complementary sets of tensioned tendon-like cables (or tapes) serve both to ...
5
votes
3answers
3k views

Rigid bumpers vs shock absorber bumpers

This question got into my mind when I am cleaning my motorcycle. If spring shock-absorbers like the one below absorbs shock from road imperfections, reducing strain in the motorcycle body as your ...
5
votes
2answers
77 views

Is there a pressure relief mechanism that operates faster than sound in a material?

In the event of an explosion through a high pressure gas pipe, is there a way to vent the pressure wave, in order to protect downstream objects? The mechanism must be faster than sound; pressure ...
4
votes
1answer
258 views

What is this contraption?

If this is the wrong place for this question, please migrate it to someplace where it's more suitable. So one of my old teachers from my previous school sent me a contraption to try and figure out ...
4
votes
1answer
34 views

What is the reason for the intermittent motion and blocking of light during change of frame in Conventional projector?

Conventional Film projectors do not advance from one frame to another by continuous movement of the reels. What is the reason for the intermittent motion and blocking of light during change of frame ...
4
votes
1answer
1k views

How does a flexible endoscope turn?

By flexible endoscope I mean colonoscope, gastroscope, etc. From this video I can see that an endoscope can swivel its tip while in place, kind of like a periscope. But while moving axially, i.e. "...
4
votes
1answer
79 views

How to trace a square with a reuleaux triangle

I am trying to trace a square (with rounded corners) using a reuleaux triangle and a single (circular rotation) motor. I've seen many animations (example) of this but do not understand how to make it. ...
4
votes
1answer
110 views

How is linear motion achieved in this automatic blackboard eraser?

In the animation shown below what can be the mechanism used for this purpose? I know it can be achieved by using rack and pnion gear arrangement. But how are this set up arranged in classroom ...
4
votes
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. ...
4
votes
0answers
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
votes
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 ...
3
votes
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 ...
3
votes
2answers
624 views

How this radio knob converting a rotation into a straight-linear motion?

Few months ago I opened the boards of an old, scrap radio-cum-tape-recorder (Philips DR183); whose tuning knob (that adjusts the gang); was very peculiar. ( * I did not found its datasheet on web) ...
3
votes
3answers
424 views

what college level teaches mechanical linkage design?

I'm 17 years old and learning first-year college math. What college level math do I need for mechanical linkage design? Can I learn designing and creating mechanical linkage without math but with my ...
3
votes
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 ...
3
votes
3answers
190 views

~121:1 speed reduction; are more gears better?

Taking a 1750RPM 110VAC appliance motor down to about 60RPM, maybe a little less. It's a home project on the cheap, so dropping a few hundred dollars on a ready-made gear box is to be avoided, and I'm ...
3
votes
1answer
2k views

Mechanism to translate rotation into reciprocating horizontal movement

I am building a machine, and one of it's components is a mechanism that will convert rotational energy to a reciprocating horizontal movement. I am aware of various mechanisms such as the Scotch Yoke ...
3
votes
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 ...
3
votes
1answer
160 views

What mechanism do I use for this pen-like design?

I am trying to make a pen-like product that moves out fluid from its tip for some special chores, but I am having issues about the motion of the clutch. The picture you see is a sectioned concept ...
3
votes
1answer
60 views

Supporting a Chain While Its Size is Varied

I am trying to model a machine that uses eyelets to support a piece of fabric, and this design uses a chain to hold the eyelets in a loop; the links are pictured below. As this machine runs more and ...
3
votes
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
votes
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 ...
2
votes
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 ...
2
votes
1answer
83 views

What can be the mechanism used in devising a machine that can arrange the dishes properly to make the cleaning faster in the messes/hotels [closed]

In hotels/messes the used plates are often placed haphazardly, and the workers need to pick the plates carefully to clean them. This leads to longer washing times and longer waiting times for ...
2
votes
1answer
45 views

How can I modify a pair of two-way switches so that the circuit can also be opened or closed remotely using a device?

I have a pair of two-way switches at different floors to control a light bulb. I wish to put an Android-phone-controllable external switch over either switch to flip it up or down. I am familiar with ...
2
votes
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'...
2
votes
3answers
1k views

What components are needed to reverse the direction of a belt conveyor using one reversible motor, and how do they change the tension on the belt?

On regular conveyor belts, motors are usually placed on the head shaft where material is discharged, and tension is highest at the entrance of this head shaft. However, if the motor were to be simply ...
2
votes
1answer
98 views

What is this linear movement mechanism called?

Does anyone know what this mechanism for linear movement is called? I have a different model of something like this, and the black chain appears rigid, so I assume it is the mechanism moving the laser ...
2
votes
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 ...
2
votes
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&...
2
votes
3answers
130 views

recreating old mechanisme

I'm recreating an old mechanisme in 3d modeling software. The idea is that this triangular shape rotates around an off-center axis. This will create 4 phases. first (like in the picture) the ...
2
votes
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 ...
2
votes
2answers
413 views

What is this captive screw and barrel nut adjustment assembly called? Picture attached

I'm designing a precision adjustment bracket, and I'd like to have a component that allows the field tech to make small adjustments to push and pull on each axis of adjustment. I went looking to see ...
2
votes
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 ...
2
votes
1answer
51 views

Is there a way to convert a short throw in one direction into a long throw in two directions

I have a motor that I have created a simple adapter for; this lets us attach any parts we might design to solve the final problem: I would like to convert the motors motion to oscillating motion in ...
2
votes
1answer
90 views

What mechanism is available to rotate a metal piece on another metal piece?

I am trying to find some type of mechanism where I can have a smooth but not too stiff rotation between two metal pieces. I was thinking of putting a shoulder screw through the pieces (the pieces will ...
2
votes
1answer
239 views

Ackerman steering

I'm designing a steering mechanism following the Ackerman principle. I've met the condition that my steering arms' normal projections must cross in the middle of the rear axle however when I do a turn ...
2
votes
3answers
108 views

Aircraft carrier arresting cables

I recently was at the Naval Air Museum in Pensacola Florida. There are lots of models of aircraft carriers, including the latest class (Gerald Ford class as I recall). This latest class has ...
2
votes
1answer
101 views

How Infinadeck Omnidirectional Treadmill works

I have seen this paper about the Omnidirectional Treadmill With CAD model ( with tiny rollers on it): Which compered its prototype with infinadeck as shown below: but don't see those roller in ...
2
votes
1answer
105 views

Latch Mechanics

I want to make a sprung latch mechanism which keeps a door in place until a certain force is applied to the door. In the diagram attached, the force the door must release at is Fd, and the latch ...
2
votes
2answers
67 views

What kind of mechanisms are there to give an object free rotation?

I am doing a project where there is a plate with a hole on it where one ring will be mounted. The ring and plate need to be attached somehow. However, the ring must be able to rotate around the roll ...
2
votes
1answer
68 views

Whats the correct name for the filament driving mechanism used in 3d printer extruders and MIG wire feeders?

Looking for the correct terminology to for the cable/filament feeding mechanism used in 3d printer filament feeder where the filament is gripped between a bearing and a gnarled gear tooth driven by ...
2
votes
3answers
544 views

One way/locking mechanism without springs or flexible members

There a few neat mechanisms that allows only one way motion without the use of a pawl or ratchet. This is one of them: https://www.instructables.com/id/LEGO-Technic-One-Way-Gear-Mechanism/ What I'm ...
2
votes
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 ...
2
votes
1answer
189 views

Bearing and Bearing Housing for Said Design

The system that I'm working on has a rotating cylinder (cleaning head). It needs to rotate vertically between two arms, much like a cleaning brush in a car wash. Note: I have not considered how the ...
2
votes
1answer
77 views

Gears and rotation

I have to project a mechanism that transform a rotation of $30 \pi/\text s$ from a engine in a rotation of $(\pi/4)/\text s$. One of the gears should be 120x bigger than the other, but this is too ...
2
votes
1answer
125 views

How to make an arduino pick an individual plant seed?

I am trying to build a robot which would plant seeds instead of humans doing it (lettuce, radish and so on). The only problem i have so far is picking an individual seed. How could i do it? I've seen ...