Y Pant School
A Mechanical Toy
Information Booklet for Year 7
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Linkages and How They Work
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Linkages link or connect moving parts together.
They enable movement to be transmitted from ‘A’ to ‘B’.
Linkages can be made from almost any material. We will be using strips of hardboard and split rivet pins.
See the examples of different linkages here. Each linkage has a different motion. Use these ideas to help you later with
your designs.
This linkage reverses the motion put
into it. The pivot or fulcrum is in the
middle of the simple lever so the
output travels the same distance as
2 of linkage is
the input. This type
called a reverse motion linkage.
This linkage also reverses the input
motion, but because the position of
the pivot has changed on the simple
lever, the input motion is small and
the output motion is much larger.
This is also a reverse motion
linkage.
Push pull linkages produce input
and output motion in the same
direction. By moving the fixed
pivots the size of motion can be
changed.
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Useful Linkages to Consider
Look at the examples on this page to see how different linkages could be used. Use these to help you when thinking of your
ideas.
Key
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Fixed Pivot
Loose Pivot
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Levers and How They Work
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A lever is a single bar (or linkage part) that has a pivot point.
Levers are usually used to enable a small force to move a much larger load. When we mention ‘forces’ and ‘loads’ in
levers, we usually refer to the pivot point as the ‘fulcrum’.
Levers can enable a small input movement to be magnified in the output and vice versa.
See the examples here of how the position of the fulcrum can affect the lever.
Pivot to the left
When the pivot (fulcrum) is
positioned left of centre, the
range of movement in the handle
end is small compared to the travel
of the object end.
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Pivot Central
When the pivot (fulcrum) is
positioned in the centre, the
distance of travel at the object
end is equal to the travel at the
handle end.
Pivot to the right
When the pivot (fulcrum) is
positioned right of centre, the
range of movement in the handle
end is greater than the travel in
the object end.
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Examples of Characters and Movements
In this section you will see examples of the types of characters that are appealing to very young children. Along side each
one you will find comments about the types of movements that could be achieved.
There are a number of parts,
which could be made to move
here. The obvious part would
be to move the arm in a
waving action. The head or
the eyes could be made to
move from side to side.
This character would be
attractive to young persons.
In this example, you could
decide to move the arms in a
waving motion or the legs as if
jumping. Her head could move
side to side, or the ears up and
down.
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Animals are usually
straightforward to design
and make. In this example
of a bird, the whole body
could move as if it was
pecking at food. The wing
could be made to flap, or
you could even have the
beak to open and close.
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Examples of Characters and Movements Continued
Sweep is a character from the
Sooty Show. From this
example his ears would be easy
to move up and down. It would
also be quite funny to move his
eyebrows up and down.
Spot the Dog would be a
fairly straightforward
character. He can be drawn
in a number of positions,
which would allow for a
variety of moving parts. In
this example, the two parts,
which stand out most, are
his, ears and
6 his tail.
This Teletubby is in a
different pose to the example
on the previous page. If you
were to make this design for
example, the head moving side
to side, or the arm waving up
and down seem obvious
choices.
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A Childs Toy – Suitable Mechanisms
A mechanism is a way of turning one kind of force into another kind of force. One example is a pair of
pincers used to remove a nail. The pincers are rotated and the nail is pulled out.
Reciprocating
Oscillating
Linear
Rotary
Mechanisms can be combined to form a machine. A machine may increase the speed of an operation. Or it may increase the
distance travelled. Or it may increase the force that operates. Machines use energy and produce work. Machines can only
produce work when energy is supplied. Energy cannot be created. The work produced by a machine cannot be greater than
the energy put into the machine. If a machine did exactly the amount of work equivalent to the energy supplied it would be
100% efficient. But most machines lose energy as heat or light. They are less than 100% efficient. For example, the
engine in a car is only about 30% efficient.
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Mechanisms use or create motion. There are four kinds of basic motion. Linear motion is motion in a straight line.
Reciprocating motion is motion in a straight line but backwards and forwards. Rotary motion is motion in a circle.
Oscillating motion is in a circle but backwards and forwards.
A Childs Toy – Suitable Mechanisms
On this page, and the next, are examples
where levers are used to produce
movement. The position of the pivot is
very important. It decides how much
movement takes place and the direction it
moves
Pivot
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A Childs Toy – Suitable Mechanisms
Here the linkages are connected
using elastic bands. You must be
careful not to overstretch them,
as they will break if you do.
Not all these designs are finished, but
can you see how they are meant to work?
Draw some designs for a cord or zip pull
with moving parts. You could base your
design on one of the ideas shown here.
Show how you could make them work
better or look more interesting, or think
up other ideas.
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A Childs Toy – Suitable Mechanisms
Here pushing and pulling operate
the linkages. The levers are
made from lightweight steel
bar. Note the sample designs on
the next page; perhaps
something here will help you to
make progress.
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A Childs Toy – Suitable Mechanisms
Design Brief – Using the materials provided (6 – 12 mm dowel rod and plywood
210 x 150 x 6) design and construct a funny face toy that includes a mechanical
movement.
Things to think about:
Happy
Sad
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1.
2.
3.
4.
3 weeks for project.
What makes a funny face?
How can I make it work?
Can I get any information on
mechanical movements?
5. Have we any toys or things at home
that might help?
6. What part of the face shall I make
move?
7. How big can it be using the materials
provided?
8. Can I use felt pens on Plywood?
9. Perhaps use Meccano to try out ideas.
10. Go to library on the way home from
school.
11. Use card and pins for ‘mock ups’ if I
can’t find meccano to work and exact
sizes.
It is now time for you to
begin your own designs.
Sketch ideas so that you
clearly understand what
you would like to do. Use
any of the mechanical
principles shown and devise
a toy to fit the brief.
Label each sketch to
explain your ideas. When
you are happy with your
work make a sketch of the
mechanism, FULL SIZE.
You will need to experiment
with card to test that your
levers and pivots are
positioned correctly.
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Cross Eyed
A Childs Toy – Suitable Mechanisms
Development of Ideas – Mechanical Movements
Loose Pivots
Loose
Pivot
Side Guide
Fixed Pivot
I will now see if I can
get two arms to move
by putting two more
arms onto my meccano
mock up.
It does, I will now use
this idea.
Loose Pivots
Fixed
Pivot
This method does not do what I
want: Part B goes up and down and
Part A 12
moves from side to side as it
is moved up and down.
This method is in my book on
linkages. When part A is
moved up and down
Fixed Pivot
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Mechanical Toy – Year 7
You have designed a lever system for your mechanical toy. It is made from hardboard and linked together with nuts and
bolts at the pivot points.
Using the same materials, and remembering the pivot points, holes and slots, design the lever systems for the following
toys:
Figure
Figure
Figure
Figure
1 – When the lever is pushed to the right the eyes move to the left and vice versa.
2 – When the lever is pushed up the ears go down, and vice versa.
3 – When the leg/lever is pushed up the arms, other leg and hat go down, and vice versa.
4 – When the nose is turned one way (e.g. clockwise) the hat goes up and down continuously.
Make your sketches large so that plenty of room is available for detail. Use one side of A4 for two drawings, so you can
complete the work on two sides of one sheet. Put your name on the paper and bring it to your next lesson.
Figure 1
Figure 2
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Figure 3
Figure 4
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Y Pant School – Design and Technology Department
Safety Policy
SAFETY CODE – THE DESIGN AND TECHNOLOGY DEPARTMENT
The room/workshop is a much safer place to work if you follow this code:
Before the lesson starts you must:
1. Never go into a room/workshop without permission.
2. Always walk into the room/workshop and never run or push anyone.
3. Always remove/secure your coat, watch jewellery, etc. as appropriate.
4. Always roll up your sleeves, and fasten loose clothing etc.
5. Always tie back long hair or use and appropriate hat.
6. Always wear strong protective clothes.
7. Always put your bag under the bench or where your teacher tells you to put it.
During the lesson you must:
1. Always know exactly what you are doing. If not ask your teacher.
2. Always obey your teacher’s instructions.
3. Always work sensibly and quietly to minimise hazards and in order that instructions can be heard.
4. Always wear safety goggles/glasses/masks/respirators, etc. When told to do so.
5. Always wear an apron or other protective clothing when necessary or when specifically told to do so.
6. Always put your stool under the bench if you leave your seat for any reason.
7. Always stand when you are doing practical work and put your stool under the bench.
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8. Always report
an accident or breakage immediately. If you spill anything on yourself, immediately wash with water
and call for your teacher’s help.
9. Never put anything in your mouth. Do not eat, drink or chew gum.
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10. Never interfere with equipment.
11. Never put glass or solids in the sink.
12. Never sit on benches unless instructed to do so for demonstration purposes.
13. Never remove a safety guard.
At the end of the lesson:
1. Always wash your hands at the end of the lesson.
2. Always wipe the benches, tables and sink areas if they are wet.
3. Always leave the room/workshop clean and tidy.
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