R Pin

What is R pin?

R-pins, also known as R-clips, R-key, hairpin cotter pin, hairpin cotter, bridge pin, hitch pin, or spring cotter pin, is a type of fastener made from springy material like a hardened metal wire. They have a straight section that bends to form a ring-shaped head, followed by a curved section that is offset from the straight part of the pin. This resembles the shape of the letter “R”.

How R-Pins Function

R-pins are commonly used to secure the ends of round shafts such as axles and clevis pins. The straight section of the R-pin may be pushed through a hole in a shaft, while the curved section clips around the outside of the shaft, retaining it in place. To help in insertion, R-pins have bent legs opposite of the straight part right after the curved portion. The angled end makes it easier for the R-pin to open up until the widest part of the curved portion is reached

A Single and Double Coil R-Pin

Depending on use, R-pins are available in single coil or double coil types. The single-coil type is mostly used for general applications, while the double coil type is for more demanding use. The double coil type is also used to facilitate the attachment of a retaining tether to prevent the pin’s loss when it is removed. Double coil types also stress more evenly compared to single coils for longer service life.

R-pin Uses

The common application of R-pins is for trucks, towing and haulage, motor homes, utility vehicles, trailers, and campers. They are also used in mining, automobile manufacturing, transport, marine, and defense vehicles. The terms below are for what they are commonly used for:

Hitch pin clips – Hitch pin clips are fasteners used to prevent hitch pins from becoming dislodged from their intended applications. They are important safety measures that secure equipment from breaking free and causing damage. Hitch pin clips are mostly used in trailers and agricultural implement components.

Hood pins – Hood pins are safety measure devices used to prevent hood panels of cars from opening up should the main latch fail. Most race cars make use of hood pins to prevent accidents at high speeds.

Button attachments – Brass R-pins can serve as button attachments for certain military, railroad, or other uniform jackets.

Body fasteners for radio-controlled cars – R-pins serve as a securing mechanism for RC cars, preventing the body frame from being separated from the motor.

R-pin Material

To fully function as securing devices, most R-pins are usually made from springy materials to facilitate durability and flexibility. It is also important for these clips to be long-lasting, so most are made from corrosion-resistant materials like zinc coated steel and stainless steel. Depending on the environment and use, R-pins can also be made from special alloys like beryllium copper alloys. These can be aged and hardened to exhibit spring-like properties while also being highly conductive, high strength, and capable of operating in extreme temperatures.

R-pin Standard Sizes - DIN 11024

Standards are a key part of international trade as they ensure quality and safety in both products and services provided by manufacturers worldwide. These standards minimize defects, improve quality control, and make systems safer and more efficient. R-pins benefit from international standards with the DIN marking or the Deutsches Institut für Normung, a German national organization responsible for unifying products and processes, such as quality performance, characteristics, dimensions, etc. The DIN 11024 standard for R-pins ensures consistency and quality for product manufacturing. DIN 11024 form D stands for double coil spring cotter pin & DIN 11024 form E stands for single coil spring cotter pin. The figure and table below show the different dimensions available for DIN 11024 R pins.

DIN 11024 Form D - Double Coil Spring Cotter Pins Dimension:

r pin form d

d1 (mm) d2 (mm) d3 (mm) d4 (mm) l (mm) Weigh in kg/100 pcs
2.5 9.0-11.2 2.25 20 42 0.59
3.2 11.2-14.0 2.8 20 48 0.99
4 14.0-20.0 3.6 20 64 1.89
5 20.0-26.0 4.5 25 80 3.54
6.3 26.0-34.0 5.6 25 97 6.18
7 34.0-45.0 6.3 30 125 9.7
8 45.0-56.0 7 30 150 13.4

DIN 11024 Form E, Single Coile Spring Cotter Pins ( R clips ) Dimension:

r pin form e

D1 D2 D3 D4 L1 L2
2 10 2.5 9-14 50 25
3 18 3.5 10-16 60 28
4 20 4.5 16-20 60 30
5 24 6 20-28 85 40
6 30 7 28-40 105 50
7 30 8 28-45 105 50

To know more about R pins, please contact us at the earliest. You can mail us your requirements for open wound compression springs at sales@hariomespring.com.

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