DIN and standard parts

Screws with locking function

Screws with a locking function use various methods to prevent screw connections from losing their effectiveness.

Image of a screw with locking function - B 251.

Secure and reliable

Screw locks prevent a screw connection from self-loosening

Screws with a locking function are used when it is not possible to secure a screw connection through structural measures. They prevent the screw connection from losing pre-tensioning force or coming apart.

Method and principle

Overview of screws with locking function

Material

In addition to steel in various strengths, available materials include A2 and A4 stainless steel, plastic and brass.

Surfaces

Our products can be coated with different surface finishes, depending on requirements and application. We will be pleased to give you individual advice on the right coating system.

We offer the following surfaces as standard:

Plain
Zinc plated (industry standard)
Thick-layer passivated
Zinc-nickel
Zinc flake

Working principle of the locking functions

Depending on the required locking mechanism, the design of the screw geometry can prevent a screw connection from loosening. The locking functions can be categorized as follows:

Setting locks

These use elastic components to compensate for relaxation and creep phenomena. As a result, a portion of the pre-tensioning force can be retained and the connection holds fast.
Locking devices

These increase the friction on the screw bolt using chemical or mechanical locking mechanisms. The increased torque prevents full loosening of the connection. At the same time, loss of pre-tensioning force can be kept to a minimum.
Anti-rotation locks

By causing the partner threads to lock mechanically or adhere to one another, these are able to maintain at least 80% of the previously applied pre-tensioning force, even when subject to high dynamic loads. This is essential to keep a component in operation in safety-relevant applications.

Find the right solution for your application

Types of screws with locking function

Thread-rolling screws
The screws create their own thread when installed in an existing pilot hole. The mounting surface material must be softer than the screw material. Advance thread cutting can be dispensed with, resulting in cost advantages in many cases. At the same time, the lack of backlash in the connection achieves a locking action.

Standards

DIN 7500 C

DIN 7500 D

DIN 7500 E

DIN 7500 M
Self-locking screws
Self-locking screws such as RIPP LOCK® and hexagon self-locking screws, provide effective protection against loosening through ribbing or toothing under the flange head. During installation, this digs into the component surface, preventing the connection from working loose, without the need for additional washer elements.

Standards

B 158

B 251

B 53085
ZAHN self-locking screws
ZAHN self-locking screws are effective mechanical locking devices that prevent the connection from working loose. The locking effect is achieved by the locking teeth, which penetrate the surface of the clamping part during installation. For this to work, the screw material must be harder than the mounting material. If you want to minimise damage to a surface, we recommend using RIPP LOCK® self-locking screws.

Standards

B 151