We see gears in use in everyday life. Often, they are used in tools like wine openers, can openers, in fans and bicycles. But how do gears work? Lets find out. A gear is a component within a transmission device that transmits rotation force to another gear or device. A gear is a round wheel which has linkages ( teeths or cogs ) that mesh with other gear teeth, allowing force to be fully transferred without slippage. Depending on their construction and arrangement, geared devices can transmit forces at different speed, torque, or in a different direction, from the power source.
A gear's most important feature is that gears of unequal sizes (diameters) can be combined to produce a mechanical advantage, so that the rotational speed and torque of the second gear are different from that of the first.
Now that we understand what gears are, i may include them in my D&T toy research =D.
The Time Euu Post;
4:49 AM
Friday, April 18, 2008
Ratchet
A ratchet is a device that allows linear or rotary motion in only one direction, while preventing motion in the opposite direction. Ratchets are used in many other mechanisms, including clocks, capstans, turnstiles, spanners, winders, cable ties, jacks, screwdrivers, and hoists.
Now, there is another mechanism that involves the ratchet. Its called the ratchet and pawl. Its based on a wheel that has teeth cut out of it and a pawl that follows as the wheel turns. Ratchets have the form of a gearwheel or linear rack with teeth, and a pivoting springloaded finger called a pawl that engages the teeth.
The Time Euu Post;
7:59 PM
Thursday, February 28, 2008
Pulley Systems
The pulley is a simple machine that consists of a grooved wheel and a rope. Like a lever, it provides a mechanical advantage in lifting a heavy load. Pulleys are used to change the direction of an applied force, transmit rotational motion, or used as a mechanical advantage in either a linear or rotational system of motion.
The most basic pulley is the fixed pulley and the movable pulley: Fixed Pulley --------------------------------------------------------->>>
A fixed pulley is a pulley in which the wheel does not move. Fixed pulleys change the direction of the effort force. It does not increase the size of the effort force. The effort force is equal to the resistance force in a fixed pulley
A movable pulley is a pulley in which you have to pull or push the pulley up or down. Movable pulleys reducecs the effort to lift the load. The movable pulley acts as a 2nd class lever as the load is between the effort and fulcrum.
The Time Euu Post;
4:49 AM
Monday, January 28, 2008
Cranks Sorry arh last week never post, cos not free. Ok so today we are going to discuss about cranks. A crank moves in linear motion, back and forth, is transferred to a circular motion or vice versa. Cranks have many uses and they can be found in some toys as part of a mechanism or in serious machinery such as factory robot arms. Cranks also have sub-groups like:
-Crank & Slider -Crank Shaft
Crank & Slider These types of cranks are usually seen in steam trains. When the slider moves left, it would turn the wheel for 180 degrees first, then when it moves right, the wheel will complete the other 180 degrees.
Crank shaft The crankshaft, is the part of an engine which translates reciprocation linear piston motion into rotation. Thats all for today, we'll talk about other mechanisms next week. Got to go do my homework =D.
The Time Euu Post;
4:16 AM
Tuesday, January 8, 2008
When we write or read about mechanical toys, we must first understand it first. After much research, i found out CAM toy is not a mechanical toy! A CAM is a part of a rotating wheel or shaft (mechanism) that comes in contact with a lever at one or more points on its circular path. It also consists of 2 parts: -Follower -Cam profile
There are also other types of followers that serves many different purposes. For example:
Roller Follower
The roller follower is a bearing with a high-rigidity shaft and a built-in needle bearing for linear motion.
Flat Follower
Pointed Follower
Other than CAM mechanism, there are others:
Cranks
Pulleys
Gears
Ratchets
Levers
Logging out will update every week tata!
The Time Euu Post;
4:02 AM
Tuesday, December 25, 2007
Cam toys, aka mechanical toys, are powered by mechanical energy. They use a series of such as levers or pulleys to make a small object move or function.
Here are some examples:
This is a picture of a cam toy, although im not sure of how this works.
Well this picture clearly gives us an idea of how cam toys work. When you turn the wheel and axle, it creates an eccentric movement which causes the follower resting on it to rise up and down.
Snail/Drop cams
Eccentric, heart shaped and pair shaped cams generally allow for a slow rise and fall of the follower. However, a snail drop cam is used where the drop or fall of the follower must be sudden. The example snail/drop cam shown opposite rotates in an anticlockwise direction. Rotating in a clockwise direction would probably lead to the entire mechanism jamming. This highlights one possible disadvantage of using this type of cam profile. Also, to ensure the rotation is smooth, the vertical centre line of the snail/drop cam is positioned slightly to the left of the slide
Swash Plate Cams
The swashplate engine is a type of reciprocating engine
that replaces the common crankshaft, with a circular
plate (Swashplate). Pistons press down on the plate in
sequence, forcing it to Nutation around its center.
The plate, also known as a wobble plate, is typically
geared to produce rotary motion. An alternate design
replaces the plate with a sine-shaped cam, and is thus
known as a cam engine.
The key advantage of the design is that the cylinders
are arranged in parallel around the edge of the plate,
and possibly on either side of it as well, and are aligned
with the output shaft rather than at 90 degrees as in
crankshaft engines. This results in a very compact,
cylindrical engine. For this reason the design is also
known as a barrel engine.
The Time Euu Post;
5:52 PM
Saturday, December 22, 2007
Sony Ericsson W910
A slider phone coated in hearty red measuring 240 x 320, 262, the W910 has a two-megapixel camera on its back, 144-colour screen on the front and a 1GB Memory Stick Micro for song storage.
It 3G HSPDA connectivity, along with blue tooth to link to steoro headsets and headphones. Its most attractive function is its shake option. By enabling the shake option, you just need to give it a little nudge to shuffle the songs. WOW! Suprisingly this mechanism also works with games......Cool!
The Time Euu Post;
11:31 PM
Profile
NAME: Moses Tsi
SCHOOL: Hua Yi Sec School
Occupation: Student under DnT training
CCA: Infoccom
![[CAM.gif]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjgQKkXVhfhKi4kHnlgT-p20ZDk_mqmejE6FKa9Ulah7uUbCeUpIvdE64o1eCCdbesQ5QzF5rLq35eZw3QoDVI4uIYLFNp0VmOMv1M_Un91WR7w9CVTi8C0MPBEQrm5g6xGEzsj96zyIA/s1600/CAM.gif)
![[roller+cam.gif]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPVXhdWqeb7GSZSuqskbKVp1NBw1zI4gpYyerDD10jgxcmi9D9MQrzgVnZPCSt6BA-MsUZbgpPmFsDSjqiI83MHRocqSbKZk6eWHfOg2g2NnxAFb9w27D-u_39pz0v09LhoIJV8u4Gn2Q/s1600/roller+cam.gif)
The roller follower is a bearing with a high-rigidity shaft and a built-in needle bearing for linear motion. ![[flatcam.gif]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh05u2doBU9rW7zSl1dJUDB7z5OWRM-CSZG8m-wOiGfZQ9ynVSscjz41pt0160jH7bM8_8aQrEEd_ASCWsGSdrXL091bq24xYs5Hvyq013SCleokzGdAh5RIqtDKw59Xju5hmoBOIZufBI/s1600/flatcam.gif)
![[point,+knife+cam.gif]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiiAIYlU4EHSZpvy0gKXgCqXwy3orLZcqkh9ZGWclRUFv5ZjhZx-z3RtMnF1QzbV11FdRuMWMiDeWqTiyM7Jqy7lBS61pcoE23sndILX0Q45GzqgGnu_ZrDskbQRBLvJwSDiXgAd5MIzgM/s1600/point,%2Bknife%2Bcam.gif)
