Rack and pinion gears are accustomed to convert rotation into linear movement. An ideal example of this is the steering program on many cars. The tyre rotates a equipment which engages the rack. As the apparatus turns, it slides the rack either to the proper or left, depending on which way you change the wheel.
Rack and pinion gears are also used in some scales to turn the dial that displays your weight.
Super Power Lock planetary Gearsets & Gear Ratios
Any planetary gearset has three main components:
The sun gear
The earth gears and the planet gears’ carrier
The ring gear
Each one of 
these 
three elements can be the insight, the output or can be held stationary. Choosing which piece takes on which part determines the gear ratio for the gearset. Let’s have a look at a single planetary gearset.
Among the planetary gearsets from our transmitting has a ring gear with 72 teeth and a sun gear with 30 tooth. We can get lots of different gear ratios out of the gearset.
Input
Output
Stationary
Calculation
Gear Ratio
A
Sun (S)
Planet Carrier (C)
Ring (R)
1 + R/S
3.4:1
B
Planet Carrier (C)
Ring (R)
Sun (S)
1 / (1 + S/R)
0.71:1
C
Sun (S)
Ring (R)
Planet Carrier (C)
-R/S
-2.4:1
Also, locking any kind of two of the three components together will lock up the whole device at a 1:1 gear reduction. Observe that the first gear ratio in the above list is a decrease — the output rate is slower than the input rate. The second is an overdrive — the output speed is faster compared to the input speed. The last is definitely a reduction again, but the output path can be reversed. There are many other ratios that can be gotten out of the planetary equipment set, but they are the types that are relevant to our automatic transmission.
So this one set of gears can make most of these different equipment ratios without having to engage or disengage any other gears. With two of the gearsets in a row, we are able to get the four ahead gears and one invert equipment our transmission needs. We’ll put both sets of gears collectively within the next section.
On an involute profile equipment tooth, the contact stage starts nearer to one gear, and as the gear spins, the contact point moves away from that gear and toward the other. In the event that you were to check out the contact stage, it could describe a straight range that starts near one gear and ends up near the other. This implies that the radius of the get in touch with point gets bigger as one’s teeth engage.
The pitch diameter may be the effective contact size. Because the contact diameter isn’t constant, the pitch diameter is really the common contact distance. As the teeth first start to engage, the very best gear tooth contacts underneath gear tooth inside the pitch size. But notice that the area of the top gear tooth that contacts the bottom gear tooth is quite skinny at this time. As the gears switch, the contact stage slides up onto the thicker portion of the top equipment tooth. This pushes the top gear ahead, so that it compensates for the somewhat smaller contact diameter. As the teeth continue steadily to rotate, the contact point moves even more away, going beyond your pitch diameter — however the profile of underneath tooth compensates for this movement. The get in touch with point begins to slide onto the skinny part of the bottom tooth, subtracting a small amount of velocity from the very best gear to compensate for the increased diameter of contact. The end result is that despite the fact that the contact point size changes continually, the swiftness remains the same. Therefore an involute profile equipment tooth produces a constant ratio of rotational acceleration.