List the materials that were used in the construction of your mechanized
toy.
·
Plywood
·
Hot
glue gun
·
PVA
glue
·
Circular
Cams
·
Shaft
·
Crank
·
Dowel
·
Sand
paper
Describe some environmental problems, which are caused by the overuse of
wood products (i.e. deforestation).
The main environmental problem caused by the overuse
of wood products is deforestation. Deforestation
is the permanent destruction of indigenous forests and woodlands. The term does
not include the removal of industrial forests such as plantations of gums or
pines. Deforestation has resulted in the reduction of indigenous forests to
four-fifths of their pre-agricultural area. Indigenous forests now cover 21% of
the earth's land surface. Deforestation is brought about by, the conversion of
forests and woodlands to agricultural land to feed growing numbers of people,
the development of cash crops and cattle ranching, both of which earn money for
tropical countries, commercial logging (which supplies the world market with
woods such as meranti, teak, mahogany and ebony) destroys trees as well as
opening up forests for agriculture, and falling of trees for firewood and
building material; the heavy lopping of foliage for fodder; and heavy browsing
of saplings by domestic animals like goats.
To compound the problem, the poor soils of the humid tropics do not
support agriculture for long. Thus people are often forced to move on and clear
more forests in order to maintain production.
Another environmental problem that is caused by the overuse of wood
products is pollution. Pollution
is the introduction of contaminants into the natural environment that causes
adverse change. When a tree is chopped down to make paper, it goes through
factories, which use up energy creating greenhouse gases, such as carbon
dioxide. The waste from the factories then gets dumped into places such as the
river creating pollution, which is very bad for the environment.
Explain the difference between ‘open-loop and closed-loop’ control
systems. Give an example of each.
A closed-loop control system is a
system in which the output has an effect on the input in such a way as to
maintain the desired output value. An open-loop control system is a control system
that does not have a feedback loop and is not self-correcting. An example of an
open-looped control system would be a light switch. An example of a closed
switch control system would be refrigerator temperature
regulating system
Provide a brief description of 3 different types of mechanisms i.e.
linkage, cams
Cam- A cam is a
rotating or sliding piece in a mechanical usage used especially in transforming
rotary motion into linear motion or vice-versa. It is often a part of a
rotating wheel
(e.g. an eccentric wheel) or shaft (e.g. a cylinder with an irregular shape)
that strikes a lever
at one or more points on its circular path.
Linkage-A mechanical linkage is an assembly of bodies
connected to manage forces and movement. The movement of a body, or link, is
studied using geometry so the link is considered to be rigid. The connections
between links are modeled as providing ideal movement, pure rotation or sliding
for example, and are called joints. A linkage modeled as a network of rigid
links and ideal joints are called a kinematic chain.
Gear-A gear is a rotating
machine
part having cut teeth, or cogs, which mesh with another, toothed part in order
to transmit torque.
Two or more gears working in tandem are called a transmission
and can produce a mechanical
advantage through a gear ratio
and thus may be considered a simple machine.
Geared devices can change the speed, torque, and direction of a power
source. The most common situation is for a gear to mesh
with another gear, however a gear can also mesh a non-rotating toothed part,
called a rack, thereby producing translation
instead of rotation.
Provide an in depth description of the primary mechanism used in your
toy
The primary mechanism used
in my mechanical toy is the circular cams. In ‘ocean motion’ there are no cam
followers but each individual wave piece acts as its own cam follower and is
moving up and down in contact with the cam. ‘Ocean Motion’ works because when
the crank is turned, it turns the shaft where the circular cams are attached.
The circular cams rise at different times and heights creating the wave motion
because the cams are slightly offset from the cam before it. This makes each
wave piece lift up at different times.
Evaluate your finished product in terms of ergonomics, aesthetics and
function.
Although my mechanism ‘ocean motion’
is not fully completed, I have a fair idea of how my finish mechanical toy will
turn out. Ergonomics relates to the artefacts interaction with the human body
such as things like comfort, safety, and convenience, ease-of-use and
ease-of-sight. My quite proud of the mechanism that I have produced as it is
very safe made with strong glue and extra plywood to make sure it doesn’t brake
and injure someone who might be playing with it. The edges of ‘Ocean motion’
were also sanded down with sand paper to leave no sharp edges where a little child
could potentially cut itself on it. ‘Ocean motion’ is very convenient not only
for entertainment purposes but also for decoration purposes because its
ease-of-sight is very good and it is a very interesting piece of work and looks
attractive to the human eye. In terms of its ease-of-use, my mechanism is were
fluent and is very easy to use although there are a few minor areas that need
fixing.
Aesthetics relates to the mechanisms
colour, shape, proportion, texture and any other visual aspect of the artefact.
‘Ocean Motion’ is very appealing to the human eye due its unusual shape and way
of movement with the individual wave pieces moving up and down at different
times which people would fine fascinating, and without building experience, one
would be confused to how this motion is actually occurring. I find the
proportion of my mechanism the perfect size for any space whether you’re using
it as a decoration on a table or desk or whether it is just for entertaining
purposes. It is a handy size that it is not too big and not too small. I don’t
think I will have time to paint my mechanism due the shortage of lessons we had
this term, but hopefully I can paint it when I take it home.
The function is the most important
part to evaluating your product, because even though your product might look
the part, it might not do its part. My mechanism ‘Ocean motion’ was designed to
be able to turn a crank in a clockwise direction which will also rotate cams
attached to a shaft that lift the individual wave pieces up and down at
different times. My mechanism successfully does this although it is not perfect
and is still a few areas that need improvement. However, ‘Ocean motion’ still
performs very effectively creating a wave motion efficiently and fluently. If I
were to do this assessment again I would have fewer boats on the waves and
would turn the boat sideways so it looks like the boat is actually going up and
down the wave. Ideally though, if we did get the option to do this again, I would
probably choose a different me mechanism to make like the ‘Caterpillar’ and ‘Ocean
motion’ is very time consuming and at times can be very difficult to make.
