MECHANICS - Clementoni

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Constructions 1to 301-Stacking two beams 2-Stacking beams with two pegs3-Joining beams4-Stacking three beams 5-Stacking beams perpendicularly 6-Stacking with an L-shaped beam 7-Build a square with beams 8-Stacking four beams 9-Build a parallelepiped 10-Build a simple bridge 11-Assemble cogwheels on a rod 12-Build a class 1 lever: pincers 13-Build a class 2 lever: nutcracker 14-Build a class 3 lever: tongs 15-Build the lever's fulcrum and weight 16-Assemble and test a lever with mechanical advantage 17-Assemble and test a mechanically neutral lever 18-Assemble and test a lever with mechanical disadvantage 19-Assemble a balance 20-Build and test a see-saw 21-Assemble the test stand for reverse rotation 22-Build and test forward rotation 23-Assemble and test alternating movement 24-Assemble a vertical gearbox 25-Build a horizontal to vertical gearbox 26-The worm screw for lifting27-The worm screw as a reduction gear28-Using the transmission module for counter-rotation29-Assemble the gearbox with a differential cage30-An ancient war machine: the battering ram

LaboratoryMECHANICS

RACING CARS

UK SUBSIDIARY: Clementoni UK Ltd.Unit 10 - Brook Business Centre -

Cowley Mill Road – UXBRIDGE - UB8 2FX P. +44 203 383 2020 - [email protected]

MANUFACTURER: Clementoni S.p.A.Zona Industriale Fontenoce s.n.c.

62019 Recanati (MC) - ItalyTel.:+39 071 75811 - www.clementoni.com

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Assembled beams

Assembled beams

Assembled beams

Two pegs make the construction very robust!

1 Stacking two beams

2 Stacking beams with two pegs

3 Joining beams

X1

X2

X2

X2

X2

X3

4

5

6

3

Assembled beams

Assembled beams

Assembled beams

X2 X3

4 Stacking three beams

5 Stacking beams perpendicularly

6 Stacking with an L-shaped beam

X1 X2

X2 X1X1

4

Final assembled model


7 Build a square with beams

8 Stacking four beams

X4 X4 X23

3

3

1:1 3

9

X4 X4

5

Semi-assembled model


9 Build a parallelepiped

1

2

X8 X2

X3

X2

X8 X2

X1

X2

6



10 Build a simple bridge

11 Assemble cogwheels on a rod

Try it out as a spinning top!1:1

X1 26X1 41 X1 18

X1 4

26

41

18

4

4

X4 X1X4

7

SIMPLE MACHINES

A simple machine is an instrument that allows for balancing and overcoming RESISTANCE (weight, resistance force = R) with EFFORT (manpower = E).

• Pairs of levers also obey this principle.

• Levers are classified by the relative positions of the EFFORT, RESISTANCE and FULCRUM.

FULCRUM EFFORTRESISTANCE

A lever is a simple machine that is made up of a rigid bar which can rotate around a fixed point called the fulcrum.

LEVERS

Since ancient times humans have made use of many of these mech-anisms to increase their strength and enable them to accomplish great feats which can still be admired today. Wheelbarrow Pincers

Nutcracker

See-saw

Balance Pulley

8

12Build

a C

lass

1 lev

er: pince

rs

1

3

1:1

3

X4

X1

X8 X23

X2

9

Final

asse

mbled

mod

el1:1

1:1

The

FULC

RUM

lies

betw

een

the

RESI

STAN

CE an

d the

EFFO

RT.

2

1 3

31

X4

X13

X2

X2X2

X11

10

Final

asse

mbled

mod

el

13Build

a C

lass

2 lev

er: nutc

rack

er

1:1

2

2

14Build

a C

lass

3 lev

er: to

ngs

The

RESI

STAN

CE

lies

betw

een

the

EFFO

RT

and t

he FU

LCRU

M.

X2

X2X4

X2 X2 X12

X2

11

14Build

a C

lass

3 lev

er: to

ngs

1X2

X1

X2X4

12

2

The

EFFO

RT

lies

betw

een

the

RE-

SIST

ANCE

and

the

FULC

RUM.

1:1

33

Final

asse

mbled

mod

el

X2

X4X3

X2

X13

X1

X1 X2

13

Scientific analysis: mechanical advantage with levers

The lever is a simple machine built by man to perform work by reducing the force required. Two forces are applied on the rod: EFFORT and RESISTANCE. Using a lever, therefore, we have a MECHANICAL ADVANTAGE that can be calculated by considering also the length of the EFFORT and RESISTANCE arms. In the lever, the lengths of the arms correspond to the distances from the fulcrum.

ASSEMBLE AND TEST THE LEVERS15 Build the lever's fulcrum and weight

Key: = EFFORT arm = RESISTANCE arm = EFFORT force = RESISTANCE force

EQUILIBRIUM CONDITIONS x = x

MECHANICAL ADVANTAGE A = /

ra

R

ea

E

ra

R

ea

E

ra R ea E

R E

FULCRUM

1 X1

X3

X2X4

X1 X7

14

In Activities 16-17-18 try moving the fulcrum and then applying downward pressure to the EFFORT arm with your hand to see the differences between the levers.

ASSEMBLING THE WEIGHT

2

Assembled weight

3

3

X2

X1 3 X2 X4

X1

X2 X2

X1 3 X2

X2

X2

15

16 Assemble and test a mechanically advantaged lever

Find the equilibrium of this type of mechanical device: position the weight (RESISTANCE) on one side of the lever and gently press down with your hand (EFFORT) on the other side.

Note the position of the fulcrum!• The EFFORT arm is longer.• The EFFORT is less than the RESISTANCE.

RESISTANCE

EFFORT

FULCRUM

TRY IT OUT!


Note: slide a collar onto the rod at the fulcrum to secure the lever, as shown.

X1

16

17 Assemble and test a mechanically neutral lever


Note the position of the fulcrum!• The arms are the same.• The EFFORT is equal to the RESISTANCE.

RESISTANCE

EFFORT

FULCRUM

TRY IT OUT!



X1

17

18 Assemble and test a mechanically disadvantaged lever


Note the position of the fulcrum!• The arms are the same.• The EFFORT is equal to the RESISTANCE.

RESISTANCE

EFFORT

FULCRUM

TRY IT OUT!



X1

18

19Ass

emble a

balance

20

Build

and t

est

a s

ee-s

aw

TRY I

T OUT

!Fin

al as

semb

led m

odel

The b

alanc

e is a

clas

s 1 le

ver

3

3

3

1:1

3

X2

X4

X2

X6X1 X2 X1

X33

X3

19

20

Build

and t

est

a s

ee-s

aw

1:1

3

3

1:1

2

2

2

1X4

X2 X2 X2X2

X13

X6

X2

X22

20


The see-saw is a class 1 lever

In the third century BC, Archimedes was a great scientist and experimenter with levers.

Note: the lever of the see-saw must rotate freely around the fulcrum.

Try it yourself: find the equilibrium of the see-saw by varying the weight and distances from the fulcrum of the Resistance and Effort forces.

TRY IT OUT!

2 X2X4

21

COGWHEELS

Cogwheels transmit motion between suitably positioned axles (rods) via teeth.• In a pair of cogwheels, if one cogwheel turns in one direction the other turns in the opposite direction. One of the two wheels

transmits motion (drive wheel) while the other receives it (driven wheel).• To maintain the same direction of rotation a third cogwheel must be inserted between the two.• With two different cogwheels, the smaller one – having only a few teeth – is called the pinion, while the one with many

teeth is called the crown wheel. Multiple cogwheels make up a gear train.

1

Assembled stand

21 Assemble the test stand for reverse rotation

X2

X2

X4

X2

X12

22

2

4

1:1 4

3

1:1 3Final assembled model

Anti-clockwise

Clockwise

18

18

22

X1

X2

X1X1

X1 X1

43

X2 18

23

22 Build and test forward rotation

1:1 4

4

1:1 3

3

3

18

1818

2


Clockwise

Clockwise

1

Stand assembled in Activity 21

X1

X4

X2X1

X1 X1

43

X3 18

24

23 Assemble and test alternating movement


4

1:1 4

4

2

1:1 2

2

26

41

1


180°

2X1

X1 X5X4

X1

X1

X2 4X2 2

X1 26

41

X1

25

1


180°

24 Assemble a vertical gearbox

2

X2X4

X2

X1

X1

26

3


4

2

41

10

180°

1:1 41:1 2

2X1

X1 4

X1 2

X1 10

41

X1

X1

X2

27

GEAR RATIO

25 Build a horizontal to vertical gearbox

2

2

1:1 2


26

Carefully observe the cogwheels when they rotate and compare the number of revolutions completed by the various cogwheels. When the larger cogwheel has completed a revolution, the small-er one will have completed 4. You can prove this by dividing the number of teeth of the two cogwheels (ratio).

Example: how to calculate the gear ratio.

41 teeth (larger wheel)10 teeth (smaller wheel)

= 4.1 revolutions

1


X1

X1 2

26

X2

28

Assembled stand

PRE-ACTIVITY TASKAssemble a test stand for the gearbox elements

X12

X2

X2

X4

X2

29


26 The worm screw for lifting

1:1 3

Technical and scientific analysisTechnically called an involute, the worm screw is a cylindrical helical gear.In a worm-and-gear set, the former is called the ‘driver’, because motion can only be transferred from the worm screw to the gear and not vice-versa. The worm screw can therefore be used to lock the mating gear in a certain position.

3

18

10

2

2

2

1:1 2

Assembled stand

Stand assembled in the pre-activity task

X3 23X1X6

X2X1

X1X1 10 X1 18

30

1:1 5

27 The worm screw as a reduction gear

Gear ratioThe worm screw makes it possible to achieve high reductions.Turn the wheel and see how the gear rotates slowly.

Check the assembly!

5

5

3

10

41


1:1 2


3X1

X1

X1 10

X1 5X2

X1

X4

X2

X1 41

X1 X1

31


TRY IT OUT!

4

28 Using the transmission module for counter-rotation

Insert the module between the beams, by partially disassembling the stand. Then arrange the gears as shown in the picture.

3

3

18

12

12

12

3 3

4

X2

X6

X1 4

X1

X1 18

X3 12

X2

3X2

1:1 31:1 4


X1

32

TRY IT OUT!

29 Assemble the transmission with a differential cage

3

3 3

3

4

21

4

18

X1X2

X6

X3X1 X1

18 12

3X2

X1 4

X2


1:1 31:1 4


30

An a

ncien

t w

ar

mach

ine: t

he

batt

ering-r

am

33

30

An a

ncien

t w

ar

mach

ine: t

he

batt

ering-r

am

1 Front

X2X2

X2X4

34

2

3

3

3

5

21

1

1:1

5

1:1

31:1

21:1

1

X1

X2 X1 X3 X1X1X2

X2

5

12

3

X1

2641

41

26

X3X2

35

3

X1

X4

X1X2

X6

36

4

4


Front

1:1 4

X1

X1X2

X1

X1 4

X3X2 X5X1

MECHANICS - Clementoni

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