# Tag Info

37

The soft clicking sound you hear when coasting is the pawl going over the ratchet as in the picture below.

28

Gear ratio This is a Roller Chain drive system, and as such it's a timed system. The ratio between the two connected pieces depends entirely on the number of teeth on either end. Even if you altered the diameter of the root of each tooth so the chain can sit higher or lower, at the end of 1,000 revolutions the chain will have moved the same amount on ...

27

it is called a freewheel. Inside the sprocket gear, there is a mechanism that lets the chain engage the rear wheel only when it is moving faster than the wheel is turning; else the wheel will turn freely. They are either several spring-loaded ballbearings that self deploy when the outer ring turns faster and recoil when it turns slower than the inner ring. ...

20

A differential is a mechanical device designed to do exactly what you propose. It will allow the two motors to spin at slightly different rates while still combining the power. The most common use of a differential is in the drivetrain of an automobile in which it is used to power both wheels from one engine while still allowing the wheels to spin at ...

18

While a mechanical differential does what you ask, you don't really need it. You can connect two identical electric motors together on the same shaft. There is no "slipping out of sync" because there isn't a issue of sync in the first place. Drive the two motors the same and both will develop close to the same torque. One will have slightly more torque ...

18

I suspect that the answer to this is that, ultimately the gear ratio comes from the ratio of diameters of the gears rather than the number of teeth, although in most circumstances practicality dictates that they are proportional. Say you have a 10 tooth cog and a 40 tooth chainwheel. It's fairly simple to imagine that you could remove every other tooth ...

15

Anything that holds a shaft and allows it to rotate is called a "bearing". It could be a simple metal bushing or a complete assembly with inner and outer races holding balls or rollers. A bearing that is designed to be mounted to a surface is sometimes called a "pillow block".

12

You need very slow speeds to make precise movements of the load. At high speed, the cables will stretch as the load accelerates and decelerates and then oscillate longitudinally, "bouncing" the load up and down (and bouncing the whole crane boom as well). That is not a good idea if you want to raise or lower the load accurately through a small distance (say ...

11

In general, each tooth of an involute gear is made up of two curves: the involute curve and the root fillet. The involute curve is essential for gears to operate properly, and allows power to be smoothly transmitted from one gear to the other. The root fillet on the other hand is not involved directly with power transmission or the kinematics of the gears (i....

10

What about a crank-rocker mechanism? (source: udec.cl) When I am looking for inspiration for mechanisms, I have a look in the book Mechanisms and mechanical devices, by Neil Sclater.

10

Oddly enough, this problem can be fixed using a set of car keys and your wallet. Here are the steps to follow: 1) put the keys in the ignition of your car, start it, and drive to the motorcycle scrapyard. 2) once there, exchange several pieces of local currency for a gear pulled out of another identical motorcycle. 3) place the gear in your pocket and ...

9

There are many examples of low input speed to high output speed gearing: kitchen "salad spinner" old-fashioned hand-cranked siren electrical generator attached to a tractor PTO (power takeoff) — also wind-powered generators the "overdrive" gear in any vehicle transmission the speed regulator on a steam engine, or in many kinds of clockwork mechanisms ...

8

Oh, I get it. The typo is a missing space. It's supposed to mean "23 to 1".

8

Two meshed gears are used to transfer rotational drive between two shafts. The relative speeds of rotation are inversely proportional to the number of teeth on each gear. That is - $$\text{Input}_{\text{RPM}} / \text{Output}_{\text{Rpm}} = \text{Output gear}_{\text{teeth}} / \text{Input gear}_{\text{teeth}}$$ So, if it is desired that the output shaft ...

8

One simple way is to do the gearing in a number of stages in a gear train. Such a system uses gears which have two different gear sizes on the same wheel. In the example shown in the image below (from the How Stuff Works article on gear trains) each gear has a ratio of 2:1 such that the final ratio of the magenta gear to the blue gear is 8:1.

8

A "44.2 tooth" gear still can only push 44 links of chain per revolution, which pushes a 16 tooth cog around 2.75 times. There's no getting around that. I think that is the question that has everyone's head smoking. So I made a visualization. Here we have small gear with 40px diameter and 4 cogs and a large gear with 80px diameter and 8 cogs, respectively. ...

8

Basically several ratchets, below animation shows when you are not pedalling. In the other direction the ratchet will engage and provide force. If you lift a bike and get the wheel spinning or just leading the bike, sometimes the pedals will turn very slowly due to the friction of ratchets. Image borrowed from https://www.notubes.com/technology/neo-...

7

Option 1 - just reverse direction without affecting the speed: Bevel gears in differential gear setup, with the carrier (the axle on which the intermediate gears are located) fixed to the chassis. Option 2: reverse direction and change speed by a large amount. Planetary/epicyclic gear, fixed carrier (the green part in the image below) fixed to the chassis ...

7

Geneva drive 3D Printed Geneva Drive Anchor Escapement (Clock Mechanism) 3D Printed Anchor Escapement

7

In the lower right corner of the document/drawing, you can see four (or five) lines of text upward: UNIT: mm Another piece of useful information in the data panel is the scale, shown there as 3:1. You would be able to measure the components of the drawing and divide by 3 to determine real dimensions, but only if the drawing is printed to 1:1 and not "fit to ...

7

if you have them in line like the following picture then NO. The first and the last gear will have the same speed and the same torque (actually slightly less due to losses). if you wanted to retain a mechanical advantage you'd need 3 shafts and at least 4 gears like in the following image.

6

If I understand correctly the problem is like this The velocity of the load is $R\omega=0.5=R\underbrace{\frac{\pi}{30}\frac{15000}{n}}_\omega$ Solving for $n$ we get $$n=1000 \pi R$$

6

Electric motors typically only operate well at high speeds, and compared to something like an internal combustion engine, relatively low torque. Fixed gear ratios are used to cope with this inherent limitation. Additionally, some designs will use a gear train so that they can design a point of failure in their system that is not the motor. If the system, ...

6

Not only does the shaft have a "bearing" surface but the ends of the shaft also need something to "bear" against due to the "thrust" of the shaft in either direction. So I would add the term "thrust bearing" to the mix some where in there ... this can be as simple as adding a single steel ball for a bearing surface to each end of the shaft to deal with the ...

6

A given mass of copper and iron can only produce so much torque : increasing torque further would require more current which means (a) the increased magnetic flux saturates the iron and (b) the I^2R losses in the copper overheat the motor. So more torque requires more iron and copper; i.e. a bigger, heavier, more expensive motor. Furthermore, because ...

6

The go-to solution is bevel gears. They are used when the shafts would intersect and allow the same ratios as normal gears. You can also make one of the gears a crown gear so the other gear can be a normal spur gear. A universal joint is also an option if the angle isn't too big.

6

No. Your basic problem is that "torque is proportional to radius" is wrong. Torque is the expression of normalized rotational force independent of radius. For example if a motor can deliver 10 Nm torque, then a pulley with 1 m radius can produce 10 N of force, at 500 mm radius 20 N, at 2 m radius 5 N, etc.

6

I decided that because of the lack of threads, it was more likely to be pressed on. So I whipped up a little shopmade gear puller, gave a little tug, and off it came. As it turns out, the gear and the spacer that I'd thought to be two pieces was actually one piece, and the key was under the spacer rather than the gear. Mystery solved.

6

Pitch diameter is the diameter of the pitch circle described by the mid point of the length of the teeth around the gear, as shown in this diagram: The pitch circle defines the point where the teeth of two gears meet: Let's say you have two gears, each with a respective pitch circle diameter of $d_1$ and $d_2$. The distance between the two gear centers, $C$...

6

Generally gear trains with lower ratios are more efficient due to reduced amount of sliding action between the gear teeth in mesh, so the compound gear train would probably be a better solution. That also depends on the quality of the gears, center distances, bearings, lubrication and thermal considerations, but short answer is two stage would probably be ...

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