Bybliographycal Research of Analysis of Mechanisms
Bybliographycal Research of Analysis of Mechanisms
Bybliographycal Research of Analysis of Mechanisms
MECHANICAL-ELECTRICAL ENGINEERING
ANALYSIS OF MECHANISMS
is called the coupler point, and its path when the crank is rotated is known
as a coupler point curve or coupler curve and the number of such curves are
infinite. By proper choice of link proportions and coupler point locations
useful curves may be found. A curve's usefulness depends on the particular
shape of a segment, for example, an approximate straight line or a circular
arc, or on a peculiar shape of either the whole curve or parts of it. The
coupler point because of its motion characteristic, is now the output of the
linkage.
Why are they important to industry?
3 applications
One interesting application of the four bar linkage is found in locking pliers.
The B-C and C-D links are set at an angle close to 180 degrees. When force
is applied to the handle, the angle between the links is less than 180
(measured from inside the linkage), and the resulting force in the jaws tries
to keep the handle open. When the pliers snap into the locked position that
angle becomes less than 180, and the force in the jaws keeps the handle in
the
locked position.
In a bicycle, the reciprocating motion of the rider´s legs is converted to
rotational motion via a four bar mechanism that is formed by the two leg
segments, the bicycle frame, and the crank.
As with many other inventions of humankind, we often find that nature has
already come up with the same idea via evolution. The parrotfish lives on
coral reefs, from which it feeds, and has to grind the coral to get to the
polyps inside. For that job, they need a very powerful bite. The parrotfish
obtains a mechanical advantage to the muscle force by using a four bar
linkage in their jaws! Other species also use the same mechanism, one is
the Moray eel, shown in the image, which has the very particular ability to
launch its jaws up in the mouth to capture its prey, much like the alien from
the film series.
What is an inversion of a mechanism?
When the number of links in kinematics chain is more than three, the chain is
known as mechanism. When one link of the kinematic chain at the time is fixed,
give the different mechanism of the kinematic chain. The method of generating
different mechanism by fixing a link is called the “inversion of mechanism
As you can see the following picture representing the crank and lever mechanism
which we can see in the beam engine. Which consists of four links.
In this mechanism when the crank rotates about the fixed center A, the lever
will oscillate about the center D. A piston is connected to the beam CDE at
the end E point. This piston will reciprocate in the cylinder due to the rotation
of the crank AB.
As the name implies, there will be two cranks present in the four-bar chain
mechanism. In a locomotive application, the weels will be connected with a
connecting rod as shown in the below picture.
In this Mechanism, there are 2 links (AD, BC (equal lengths) acts as the cranks,
and the one link(CD) acts as the connecting rod or coupling rod. and one link(AB)
is fixed.
This mechanism will transmit the rotary motion from one wheel to the other.
As the name implies, there will be two levers present in the four-bar chain. This
Double lever Mechanism is known as the watts indicator mechanism also.
In this mechanism, we have four links A, AC, CE, BFD. These links BFD will be
having two bodies BF, FD but they will make only one link due to they do not have
any relative motion to one another.
In this mechanism, The links CE and the BFD will act as the levers. The linear
motion of the indicator plunger will be transmitted the same on to the indicator dial
or a scale.
This mechanism will transmit the linear motion from one end to the other.
7. Explain its relationship with the cam-follower and the scotch yoke
mechanisms.
The cam follower is a compact bearing with an extremely rigid shaft and an
integrated needle bearing. It is well suited as a guide roller for cam mechanisms
and for providing linear motion on automated and specialized machines.
The Scotch Yoke (also known as slotted link mechanism) is a reciprocating motion
mechanism, converting the linear motion of a slider into rotational motion, or vice
versa. The piston or other reciprocating part is directly coupled to a sliding yoke
with a slot that engages a pin on the rotating part.
The Scotch Yoke is a mechanism for converting linear motion of a slider into
rotational motion or vice versa. The piston, on the other hand, is directly coupled to
a slide with a slot for it to make a pin in the rotating part. The shape of the piston
motion is a pure sinusoidal wave in time, at a constant given rotational speed.
Both are a mechanism used to obtain the desired motion, such as reciprocating or
translational, from an available input, usually rotational. The cam and follower can
be found on the market in different sizes and shapes.
Referencias:
Norton, R.L., (2020), Design of Machinery, 6th ed., McGraw-Hill Education
Mott, R.L., (2004), Machine elements in Mechanical Design, 4th ed.,
Pearson/Prentice Hall
Norton, R.L., (2009), Cam Design and Manufacturing Handbook, rev. ed.,
Industrial Press