What are Extension Springs?

Extension springs are helical springs designed to operate under tensile load. In their relaxed state, the coils are in contact with one another. Once a tensile force is applied, the coils extend and store energy in the process.

Construction and Materials

Extension springs are typically made from high-strength spring steel, known for its elasticity and fatigue resistance. The main materials include:

• Spring steel: The standard material for high strength and durability.
• Stainless steel: Suitable for corrosive environments.
• Special alloys: Used for extreme temperatures or specific fatigue resistance requirements.

Extension springs feature various hook or loop configurations at their ends to facilitate force transmission and ensure secure attachment to other components.

Properties and Functioning of Extension Springs

Spring Constant

The spring constant describes the relationship between the applied force and the extension of the spring. It is expressed in newtons per millimeter (N/mm). A higher spring constant indicates a stiffer spring.

Maximum Load

Extension springs are designed to withstand a certain maximum load without permanent deformation. Exceeding this limit can lead to material damage or spring failure.

Stress Distribution

Even stress distribution along the spring coils ensures a long service life, even under frequent loading.

Applications of Extension Springs

Extension springs are highly versatile and used across various industries:

1. Mechanical Engineering:

   • Tension elements in complex mechanisms.

   • Control of movement and loads.

2. Automotive Industry:

   • Return systems for gas and brake pedals.

   • Door and locking mechanisms.

3. Household Appliances:

   • Springs in washing machines and dishwashers.

   • Latching mechanisms in household products.

4. Medical Technology:

   •  Precise motion control in devices.

   •  Return springs in surgical instruments.

Loop Types of Extension Springs

Our standard extension springs are manufactured with a full German loop. The German loop is characterized by its round, symmetrical shape, offering robust and versatile use. Screw-in elements or custom loop shapes are also available upon request.

Choosing the Right Extension Spring

Key Criteria

Selecting the appropriate extension spring depends on several factors:

1. Load Requirements:

   •  How much tensile force must the spring handle?

   •  What is the required extension?

2. Material Requirements:

   •  Is corrosion resistance needed?

   •  Are there special temperature conditions?

3. Geometry:

   •  What length and diameter are required?

   •  What hook shape is needed?

4. Dynamic Loading:

   •  How frequently will the spring be loaded?

   • What service life is expected?

Standards and Norms

Extension springs are often manufactured according to established standards such as DIN 2097, or alternatively based on internal company specifications. These standards define precise dimensions and load limits to ensure consistently high quality and maximum reliability.