# Tag Info

7

You can use a sort of "double diameter washer". I've made that name up, but I am pretty sure such a device exists: That's a cross section of one of your linkages. The white things are the aluminum pieces, the grey one is the screw, the yellow is the nut while the red is the "double diameter washer". If you can found some washer that is ...

6

Six bar linkages are pretty easy to find. Six bar is the go to guy when a four bar does not offer enough movement flexibility. Bigger European style hidden hinges are nearly all six bar mechanisms, essentially they are two four bar mechanisms that share part of the structure. These are common in many uses but the sixbar hinge you can probably find at home ...

5

A shoulder bolt is a good approach in applications with light loading, but it needs to be specified such that it can be fully tightened while still allowing the necessary clearance for movement without binding. Use shims where needed. You can reduce some of the play in the joint by having the bolt threaded into one of the aluminum pieces (but still backed ...

4

What you see here is two sets of four-bar linkages connected to each other to form a six-bar linkage. To be more precise this is a Watt type 1 six-bar linkage. This particular configuration is known for its ability to fold together by rotating only one member. Image 1: The classification of some planar 6 bar linkages There is nothing inside the yellow part ...

4

It all depends on how complicated the linkage is. For many simple linkages all you need to know is trigonometry (sin, cos, tan) and torque/moment equilibrium (Force x Distance = Force x Distance). Once you can do this I would say you are in the 95th percentile of linkage design ability. Most non mechanical engineers do not have the ability to calculate or ...

4

If you wanted to use circular gears you can use the following procedure. Assuming $i$ is the gear ratio, you'd need $$i = \frac{d_1}{d_2} = \frac{n_2}{n_1} = \frac{\theta_2}{\theta_1}$$ The distance between the two centers $a= 225\ mm$ will be equal to : $$a= \frac{d_1+d_2}{2}$$ $$a= \frac{i\cdot d_2+d_2}{2}$$ $$d_2= \frac{2a}{i+ 1}$$ So assuming: $d_1$ ...

4

The design that you illustrated is pretty much correct. See below: In order for the end to move along a circular path, you want a four-bar-linkage with equal length arms. Note how the length of the medium grey linkages (60mm) is equal to the radius of the red circle (50mm), plus some clearance (10mm). Note how the distance from the centre of the red circle ...

3

This is a basic way of doing it. A rotating cam, attached to the triangle via a link through a bore in the reciprocating runner guide. The runner guide goes back an force in a path made by 4 bearings and activated by an actuator. The sketch does not show some details for clarity. It's just a starting point.

3

Figure 1. A CAD calculation for a direct linkage. You want the left wheel to turn 95° from 1 to 2. You want it to rotate the right wheel 83° from 3 to 4. The direct distance from 1 to 2 is 44.2 mm on a 30 mm radius. Construct a 44.2 mm line centred on the right linkage and project down onto the 83° symmetrical angle. The linkage pivot radius measures 33.4 ...

3

Gearing is complicated by the fact that the driver bar moves at a constant speed while the driven bar changes speed. Could this gearing Solution work? The gear should only engage when the center bar is fully extended to the right or fully extended to the left. Update: https://www.youtube.com/watch?v=I4V3NqwZG0o https://www.youtube.com/watch?v=aPUcdGnf2uk ...

3

Correct, the linkage will randomly try to switch modes at the two top dead center locations. I have actually built one in the past and attempted to power only one of the rotational bars and expected the other to stay in its mode from flywheel inertia on that leg. However, the the linkage would still randomly switch modes and abruptly (sometimes ...

3

In such cases you don't pay for the rubber, but for the administrative and storing costs. Manufacture a such rubber and then try to sell it on the ebay. With taxes, all of the law regulations, with post costs, etc. For example, if you only want a rare screw to repair a device, you can easily pay even tens of dollars for that. Why? Producing a kilo of such ...

3

Okay, it took me way too long to figure this out. I'm thinking this is just not a very intuitive interface. Here's the fix for anybody else who makes it here. Click #1, Click #2 (carefully!), then check the box at #3.

2

Answer The other ground link is not shown and neither is the floating link. This diagram only shows The 4 desired output link positions The 6 poles generated from those positions The process involved to obtain 1 link Your first two points are correct, however, P23 and P'23 do not form the next link joint. P23 is the pole of the rotation from DC to CE and ...

2

Here are some definitions for you, based on my experience with these terms: A linkage is a group of bodies (or links) connected together by joints. A kinematic chain is a subset of linkages, specifically referring to linkages with rigid, ideal joints, and rigid links. Since the joints and links are rigid, this allows you to use geometry to relate the ...

2

There are some purely geometric linkage design methods, such as two and three position synthesis (which are easy enough to teach even a 8 year old). But there are methods that are not so geometrically intuitive. The real problem with linkage design is that the mathemathics behind kinematics require a very good foundation of trigonometry and/or imaginary ...

2

To answer your title, It's not really a matter of what college level, but rather what college. For example, a general studies college (one with a broad range of majors) may not offer such a class, whereas a technical college that focuses specifically on mechanical engineering will offer a variety of these courses at multiple levels. To answer your first ...

2

This is a type of ellipsograph or Trammel of Archimededs. It's a mechanism that is widely documented in textbooks for both the kinematics and the dynamics. Regarding the second part of your question, it really depends on two things: the position of the rod (angle) the velocity at the point of calculation. In the simple case of velocity equal to zero, then ...

2

To find the lengths of the components of the linkage mechanism you are going to have to use trigonometry. I'd envisage doing so for the case when both $\small\sf\theta_1$ and $\small\sf\theta_2$ are zero. Assuming the lengths of the components of the linkage on each side of the vehicle are the same do the calculations for one side of the vehicle and use the ...

2

If you were to set up a gear mechanism, it would be two gears with circumference and radius ratio of 95/83, with the smaller gear at 95 switch. Therefore the same ratio links would rotate the switches with the same angles. Of course, only the start and stop position of the rotation is going to be correct. The other positions will be off by various ...

2

The easiest way to do this (either the direct or the inverse) is with the use of the homogeneous transformations. Basically, it is an augmented transformation matrix in 3 dimensions which can also accommodate translation (and scaling - this won;t be of much use to you). The main form is: T = \begin{bmatrix} \color{blue}{ R_{11}} & \color{blue}{R_{12}} ...

2

Another online resource you can try out is http://cadcam.eng.sunysb.edu/app/

2

The program Solvespace may be of use to your project. The first example in a Solvespace video refers to the term 'mechanical linkage' and shows a circular path for one of the pivots of the linkage, while another part of the linkage describes a semicircular path. As the 5/6 point travels on the semicircle, the 4/6 point travels in a circle. You specify that ...

1

I believe what you are seeing is a pendulum mounted on a sliding bracket. The weight with the thumbscrew indicates that it can be tuned to match the required movement to engage the V-shaped "socket" into which it engages on alternating strokes. Slowed down to one-quarter speed, the video shows that on one stroke, the pendulum is swinging left, while the ...

1

Think of the orange bar as the humerus bone in your upper arm, the blue bar as your radius, and the pink one as your ulna. The gate folds up in much the same way your arm folds up, and opens up much the same too.

1

This is called Ackerman Steering. In an ideal case a line drawn through the wheel pivot point and steering arm pivot point will cross the centre point of the rear axle when the steering is centered. In practice other dynamic effects like roll etc may mean that the best position for this point will vary a bit. As long as the steering arms are the right ...

1

To find a ready-made device that utilizes a six-bar mechanism, you can dig through some of the classical resources below. Instead of pointing out a few devices, I think it would be better to point you to these databases. 507 Mechanical Movements: Mechanisms & Devices. (amazon link). This book is also available for free as an animated database. ...

1

Steel and aluminum don't like each other! that's why you are getting the binding. Only use Stainless steel with aluminum. And of course never use aluminum fasteners for an application like this due to strength. And use all nylon washer if you can or between the SS washer and where is touches the moving part.

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