Two Pluses 3

Function and Contradiction

by Kalevi Rantanen
TRIS OY
Brahenk. 9 E 18
FIN-20100 TURKU, FINLAND
phone/fax +358 2 251 1623
E-mail: kalevi.rantanen@pp.kolumbus.fi

Last updated August 18, 1997

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No System as an Alternative
- The most ideal system
- Automatic clutch
- Exercise 1
- Exercise 2
Computer support
Further reading

No System as an Alternative

The most ideal system. The ideality of the system grows when the function is preserved
or increased and costs decreased. To increase value we should solve the contradiction or combine
two incompatible solutions:
- Good quality, high cost
- Low quality, low cost

In the two pluses matrix:

Good and
expensive Quality
+ Cost
-
Cheap and
poor Quality
- Cost
+
Good and
cheap Quality
+ Cost
+

Further intensifying the contradiction we get the pair where we have "no system" in the place
of the cheap and poor system:

Good and
expensive Quality
+ Cost
-
No
system Quality
- Cost
+
Most ideal
system Quality
+ Cost
+

Examples:
- No lubricant in air cushion or magnetic bearings, gas or magnetic field works as lubricant
- No seal in the heat exchanger, a (welding) seam itself makes the job of a seal
- No fastener, fastened components fix each other

The most ideal system carries the function with no cost:
no weight, no size, no energy consumption, no harmful side effects. The most ideal system
is actually an nonexistent system, the function of which is still delivered.

The nonexistent system is an alternative system, which is always available. When we can
describe the ideal system as the "sum" of two systems:
- Initial system: delivers benefit (+), but the benefits are coupled with costs and harmul effects (-)
- No system: no benefits (-), but no costs, no harms, neither (+)

The ideal system is a nonexistent system, "no system", which delivers the function of the
initial system.

Let´s reformulate our "frame problem" using the "no system" as an alternative:

System Waterproofness Weight
Body-
shell +
"tight" -
heavy
No
shell -
"leaking" +
light

The ideal shell is "no shell", but a cyclist is protected from rain. The function
of the removed shell should be transferred to other systems or to elements
of environment. The simplest idea is, maybe, to transfer the function of a shell to a frame.
Compare the history of a car: merging of a body and a chassis.

System Waterproofness Weight
Body-
shell +
"tight" -
heavy
No
shell -
"leaking" +
light
Frame as
shell t
"tight" +
light

Generally, there is three ways to remove or trim the element and preserve the function:

the function of the component is performed by some other component
the function of the component is performed by the component itself
there is no object of the function

The methodology for removing is called Trimming Technique (Trademark of Invention
Machine Corporation). In the beginning the idea of trimming was introduced by Semyon
Litvin and Vladimir Gerasimov.

So we have two weapons: Two Pluses Matrix (featurre transfer) and Trimming. In principle
the ideal final result can be achieved by the combination of two alternative
systems, or by removing of elements.. In practice some problems
are easier to state as the problem of alternative systems combination, some others as
trimming problem.

Since we are transferring the functions of trimmed elementis to the other parts of the system,
we should know the functions of the system and its components. Ellen Domb (see
E. Domb. How to Help TRIZ Beginners Succeed, TRIZ Journal, April 1997)
has supposed a handy table which helps to analyze the system. Let´s describe functions of
bicycle components:

Function Statement, Analysis and Trimming
A
function
carrier Does this
to B
object of
function Useful/
harmful Is the
function
necessary? Could B do it?
Some other
element?
Wheel moves frame + Yes No
Chain rotates wheel + and - Yes Chain ring?
Chain ring moves chain + Yes No
Cyclist rotates chain ring + No El. motor?
Body stops rain + Yes Frame?
Frame fixes wheel + Yes No
Frame fixes chain ring + Yes No
Frame fixes saddle + and - Yes Body?
Frame fixes body + Yes Body?
Saddle supports cyclist + Yes Body?

Function Statement, Analysis and Trimming
A function carrier	Does this to	B object of function	Useful/ harmful	Is the function necessary?	Could B do it? Some other element?
Wheel	moves	frame	+	Yes	No
Chain	rotates	wheel	+ and -	Yes	Chain ring?
Chain ring	moves	chain	+	Yes	No
Cyclist	rotates	chain ring	+	No	El. motor?
Body	stops	rain	+	Yes	Frame?
Frame	fixes	wheel	+	Yes	No
Frame	fixes	chain ring	+	Yes	No
Frame	fixes	saddle	+ and -	Yes	Body?
Frame	fixes	body	+	Yes	Body?
Saddle	supports	cyclist	+	Yes	Body?

Automatic clutch. Let´s consider yet one example. A manual gearbox and an automatic
one are well-known alternative systems for a transmission in the car. Two interesting designs -
an automatic clutch and a "shifting robot" - are attempts to combine good features of the both.
First we repeat our usual table or matrix:

System Device
complexity Ease of
use
Manual
gearbox + -
Automatic
gearbox - +
Automatic
clutch
Shifting
robot + +

Let´s now look at the same problem from the viewpoint of trimming. We consider
only one system, say, "the power transmission system" with a usual manual gearbox.
Main components of our system are:
- Engine
- Clutch
- Gearbox
- Gas pedal
- Clutch pedal
- Stick

Let´s fulfil "Domb´s table":

Function Statement, Analysis and Trimming
A
function
carrier Does this
to B
object of
function Useful/
harmful Is the
function
necessary? Could B do it?
Some other
element?
Engine transforms energy + Yes
Clutch switches
on/off shaft + Yes
Gearbox changes speed + Yes
Gas pedal changes power + Yes
Clutch
pedal switches
on/off clutch + Yes gas pedal/
stick
Stick changes transmission
ratio + Yes

Function Statement, Analysis and Trimming
A function carrier	Does this to	B object of function	Useful/ harmful	Is the function necessary?	Could B do it? Some other element?
Engine	transforms	energy	+	Yes
Clutch	switches on/off	shaft	+	Yes
Gearbox	changes	speed	+	Yes
Gas pedal	changes	power	+	Yes
Clutch pedal	switches on/off	clutch	+	Yes	gas pedal/ stick
Stick	changes	transmission ratio	+	Yes

The next part of the analysis is to simplify the system so that a number of components decreases
but the functions are delivered.
A clutch pedal is an uncomfortable component. The alternative system is a nonexistent pedal.
We rewrite our matrix:

System Control of
speed Ease of
use
Clutch
pedal +
simple -
uncomfortable
No
pedal -
No
control +
easy to use
Automatic
clutch + +

A clutch pedal can be trimmed, if the function "connects/disconnects clutch" is performed
by the clutch itself, or by the gearbox, or the gas pedal, or by some other element.

Exercise 1. Continue previous exercises: Study the system. Fulfil the "Domb´s table":

Function Statement, Analysis and Trimming
A
function
carrier Does this
to B
object of
function Useful/
harmful Is the
function
necessary? Could B do it?
Some other
element?
...
... ...
... ...
... ...
... ...
... ...
...
...
... ...
... ...
... ...
... ...
... ...
...
...
... ...
... ...
... ...
... ...
... ...
...

Function Statement, Analysis and Trimming
A function carrier	Does this to	B object of function	Useful/ harmful	Is the function necessary?	Could B do it? Some other element?
... ...	... ...	... ...	... ...	... ...	... ...
... ...	... ...	... ...	... ...	... ...	... ...
... ...	... ...	... ...	... ...	... ...	... ...

Make two pluses matrix:

System Feature 1 Feature 2
...
... + -
...
... - +
...
... + +

Can you use the nonexistent system as an alternative system?

Exercise 2. Continue previous exercises: Study the system. Can you use the
trimming principles? Consider costs and market opportunities:

How much the trimmed system can cost? Should I decrease or increase
the cost limit?
What will get if the trimmed system will be realized? Quality, market opportunities?
Will we get extra benefits not named in the previous analysis?

Computer support

Modules Function Analysis and Trimming in IM-TechOptimizer make possible
to build detailed models of components and functions. See TechOptimizer

Good and expensive	Quality +	Cost -
Cheap and poor	Quality -	Cost +
Good and cheap	Quality +	Cost +

System	Waterproofness	Weight
Body- shell	+ "tight"	- heavy
No shell	- "leaking"	+ light

System	Device complexity	Ease of use
Manual gearbox	+	-
Automatic gearbox	-	+
Automatic clutch Shifting robot	+	+

System	Control of speed	Ease of use
Clutch pedal	+ simple	- uncomfortable
No pedal	- No control	+ easy to use
Automatic clutch	+	+

Two Pluses 3

Function and Contradiction

Contents

No System as an Alternative

Computer support

Further reading