Springs are necessary
in many technical
constructions.
This article will provide
insights into the variety of
spring applications.
It will also look at European
spring manufacturers as
they describe production
examples and general
considerations
for spring design.
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Ensuring Mechanical Functions
In industrialized countries, nearly everyone uses
springs each day. Most people are not aware of it
because many springs seem insignificant or are
hidden to the bare eye. However, the significance of
a spring can be felt immediately, when it fails.
Think of when the pressed push-button of a PC
keyboard doesn’t jump back into its initial position
or a toaster doesn’t return a slice of bread. Consider
what could happen if the pressed-down accelera-
tor pedal of a car remains in its position instead
of returning back. This is a potentially frightening
scenario.
Function Principle
Regardless of the particular function of a spring,
it can be said that all springs work according to
a principle: By changing their shape, they store,
transform or set mechanical energy free. Springs are
elastic, meaning they return to their initial shape
after having been unloaded. Springs are also used
to absorb impacts or vibrations.
Some years ago, the German commercial news-
paper Handelsblatt quoted Horst Dieter Dannert,
then-secretary of the German spring manufacturers
association VDFI and current general secretary of
the European Spring Federation (ESF): “Technical
springs are everywhere, where something is moving.
Every light switch, every valve, whether in a power
station or in a kitchen, needs a spring.”
Cars, airplanes, typewriters, computers, clocks,
washing machines, mousetraps, door-handles,
coffee makers or mattresses — these are all products
most of us encounter in our daily private or business
life that contain several springs which ensure their
mechanical function.
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History
Since its very beginning, mankind has used
the elastic characteristics of natural materials and
forged metals like copper and iron. Fibulas made
from copper were used to hold together clothing and
can be seen as forerunners of modern safety pins.
Since the Middle Ages in Europe the develop-
ment of iron production and wire manfucturing had
a reciprocal influence on the applications of springs
and spring manufacturing technology.
Today’s armaments industry began with weap-
ons like crossbows and rifles that were based on
spring mechanisms. At the beginning of the 14th
century watchmakers used springs to manufacture
clockworks. Craftsmen improved continuously the
quality and the shape of springs.
In the 18th century spiral springs were generally
used for clocks and fob clocks. Today, the automotive
industry is the most important customer of spring
manufacturers, but other industries which produce
investment and consumer goods need large quanti-
ties of springs too.
Manifold Variety of Shapes
As the operating conditions can vary greatly
with many parameters acting on a spring, there is
a nearly endless number of construction possibili-
ties concerning the material, shape and design of a
spring. Springs can have a standardized shape like
the helical compression spring in a ballpoint pen,
but a simple blade or a clip can also be a spring.
Plus, there even are creations that, at first sight,
seem to be unique works of modern art.
Some years ago, at the annual VDFI convention,
Dr. Thomas Blum, then a member of the manag-
ing board of the spring machinery builder Wafios
and today a consultant for the spring industry,
showed pictures of bizarre wire forms that looked
like abstract art but were technical springs. The
curious form was the result of a phenomenon that
is well-known in the spring industry: The designer
of a complex technical system had forgotten to
consider the spring in his construction. Only at
the end of the development process had he noticed
that a spring was necessary to make the construc-
tion work. A spring manufacturer was confronted
with the task of developing a spring that could be
mounted into the space which by chance was left
free. Such springs can be manufactured on modern
electronically controlled spring coilers.
Market Requirements
The following example shows, how impor-
tant close contact between customers and spring
manufacturers is. For the North Italian spring
manufacturer Mollificio Valli Srl, situated at Oleg-
gio Castello near the Lago Maggiore, the automotive
industry has always been an important customer.
“There is a great demand for all kind of springs,”
says Angelo Passarotti, technical and commercial
manager of the company. “As these springs must
respond to severe operation and safety conditions
– for example valve springs must support without
problems a life span of 100 million (1 x 108) or more
load alternations – the quality requirements are very
high. The basic condition for success is therefore a
close cooperation with our customers,” explained
Passarotti.
“It’s not unusual that two years are necessary
for the development and the specification of a new
spring before the serial production starts,” said
Passorotti.
Tendencies
Mollificio Valli manufactures springs for many
other applications too. In the past they developed
springs for educational toys which help children
discover and train their senses. However, for cost
reasons the production of toy springs in the highly
industrialized countries of Europe is in decline and
has been replaced by countries in Southeast Europe
or China.
On the other hand, new markets are growing. For
example, there is an increasing demand for springs
which are integrated into the hinges of kitchen and
other furniture. “These springs assure a certain
kinematic for the opening or closing of doors and
lids,” explains Passarotti.
Henrik Hagens, managing director of Hagens
Fjedre AS based at Støvring, Denmark, noticed, “that
there is a general tendency towards higher forces
and load cycles, smaller tolerances and more spring
shapes. The limits of the materials characteristics are
exhausted, and there are no imagination limits.”
By following its company motto “springs while
you wait,” Hagens Fjedre AS — which manufactures
springs for many small and medium-sized companies
in practically all branches like machinery construc-
tion, agricultural machinery, energy technology,
off-shore-technology and wind power plants — is
confronted with new and sometimes original tasks.
The concept means that technical calculations and
the production of prototypes and small series are
carried out within a matter of days or even hours. “A
time ago,” remembers Henrik Hagens, “the designer
of an arts studio came to us and asked us to make
springs which then were inserted into street lamps.
These springs don’t have a technical function but
cause an aesthetic effect which one can see now in
the pedestrian zone of a certain Danish town.”
Matthias Dietz, managing director of Federn-
fabrik Dietz GmbH, is also familiar with many
different spring applications. Springs made in his
company hold the pipes of organs, while other
springs help adjust the many little mirrors of operat-
ing room lamps or control the blood flux in dialysis
automats.
The company, based in Neustadt near Coburg in
Southern Germany, manufactures springs and bent
parts which are used in many sectors like automo-
tive, electronics and electrical appliances, locks,
jewelery, decorative articles and even devices which
can help children train their motor skills.
Where do new ideas concerning the application of
springs come from? “We cultivate longstanding rela-
tions with our customers; we are of course open to
every inquiry,” says Dietz, “and have our own creative
team which stands ready to develop and produce
concepts for innovative spring manufacturing.”
Original and Witty
There are nearly no limits for the application
of springs. Here are three interesting, original and
witty ideas.
Years ago a German pedicurist developed a
spring system which immediately helps elminate
pain from ingrown nails and corrects the nail grow-
ing process. Furthermore, painful operations can
be avoided. Orthonyxists who have been trained to
apply the “VHO-Osthold-Method® perfect” are able
to apply correctly the “VHO-Osthold-Brace® perfect”
(www.VHO-Osthold.com).
Another interesting spring application has also to
do with the feet: the “Pogo Stick.” The stick is equipped
with handles, footpads and a compression spring. The
operator places his feet on the footpads while balancing
on the pole, then jumps or presses down on the footpads
to compress the spring. When the spring has been fully
compressed, the operator lifts his weight, aided by the
recoil of the spring, being launched several inches or
feet into the air. This process is repeated to create a
hopping action.
Finally there is the “Slinky”, a long coil with the shape
of a simple helix which can “walk” down stairs when
the coils stretch and reform as gravity moves them
down each step. More information on these products
are available at Wikipedia (www. wikipedia.org), the
free Web encyclopedia.
Conclusion
Springs are needed nearly everywhere. As
there is a huge variety of applications and a lot of
aspects to be considered, the requirements of all
spring applications can’t be satisfied with a few
standardized spring products. Spring manufactur-
ers can be assured of their competitiveness if they
have experience, mental flexibility, an aptitude for
technical contexts, product and production know-
how, modern production equipment, and creativity
to help their customers discover further spring
applications and new markets.
Konrad Dengler is a special contributor to Springs.
A freelance correspondent, Dengler writes about
the wire and spring industry in Europe for several
industry publications. Previously, he was editor of
the technical journal Draht. He is an engineer
in materials sciences, and works as a technical
journalist and translator. Readers may contact
him by e-mail at KDengler@t-online.de or
by fax 0049 9135 3990
For More Information:
Federnfabrik Dietz GmbH
Am Floßgraben 10
D 96465 Neustadt
Tel. +49 9568 94 42-0
Fax +49 9568 94 42-22
E-mail: info@federn-dietz.de
Web:www.federn-dietz.de
Hagens Fjedre AS
Hagensvej 13
DK 9530 Støvring
Tel: +45 98 37 14 44
Fax +45 98 37 41 43
E-mail: home@hagens-fjedre.com
Web: www.hagens-fjedre.com
Mollificio Valli Srl
Via Ceserio, 39
I 28040 Oleggio Castello (NO)
Tel. +39 0322 54 17 11
Fax +39 0322 53 80 67
Web: www.mollificiovalli.it
E-mail: info@mollificiovalli.it
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