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Seat Belts, Harnesses & Safety Restraints

Descriptions of the component parts of a Seat Belt with Links to pictures & line drawings.
Generally black and woven from thousands of strands of polyester.
Made to a high specification and designed to elongate by 10% to 15%, in an accident,
to absorb energy.
Other colours in the standard range: 'Securon'  Red, Blue, Grey and Beige.
Colours may fade and change so to achieve matching webbing buy all the Seat Belts at the same time.

Webbing must be in good condition - Fluffing, fraying or broken strands weaken webbing.
Webbing is generally about 47mm wide, wider webbing (i.e. 72mm) is used on some 'special' heavy duty applications and Race/Rally Harnesses.

Means the Seat Belt has a Retractor.

Means the Seat Belt does not have a Retractor.

Also known as Roll-up device, Inertia Reel, Reel, Automatic Seat Belt & Retractable Seat Belt.
Designed to stow webbing not in use and lock in a predetermined situation.


1. Emergency Locking Retractors (ELRs) which lock in an emergency.
They can have:

 a)   Webbing sensors which sense webbing acceleration. ie the
      retractor will lock if the webbing is snatched. Typically abrupt torso movement.


b)   Vehicle sensors which sense vehicle movement. ie the retractor will lock with sudden
      vehicle movement. Typically abrupt stopping, vibration or roll-over. Vehicle sensors require specific installation angles i.e 90°/90°.

Technical definition (from ECE R16):
"A retractor which during normal driving conditions does not restrict the freedom of movement by the wearer of the safety-belt.
Such a device has length adjusting components which automatically adjust the strap to the wearer and a locking mechanism actuated in an emergency".

2. Automatic Locking Retractors (ALRs) which lock when the lap belt is put around the wearer.

Technical definition (from ECE R16)
"A retractor allowing extraction of the strap to the desired length and which, when
the buckle is fastened, automatically adjusts the strap to the wearer.
Further extraction of the strap is prevented without voluntary intervention by the wearer."

Used to remove slack from the Seat Belt. It can be separate (in the webbing), part of the end bracket or part of another component i.e. the tongue.

TONGUE (male) connector
The part that is pushed into the Buckle
to connect the Seat Belt and is ejected when red release button is pressed to undo the seat belt.

BUCKLE (female) connector
The part into which the tongue is pushed
to connect the Seat Belt.
Generally located just on or below the hip on Seat Belts or on the lap of Harnesses.
The Buckle is connected to the vehicle by means of:

  •   A Stalk/Cable with an anchorage hole.
  •   A Metal strap with an anchorage hole.
  •   Webbing with an end bracket.

Securon manufacture the following quick release Buckles:

  1.      Twin Release Buckle (unique to Securon). Designed to be released from the top or side

  2.      Single Release Buckle.

Options 1 & 2 with Micro Switch (IP67 Rated).

  4.      Turn Lever Buckle. A  5 way Buckle which complies with FIA/ECE R16 requirements.

Often used to connect the buckle to the Anchorage Point and to help position the Buckle just on or below the hip

Used to secure the Seat Belt to the (PreDesignated) Anchorage Point on the vehicle generally by means of a 7/16"
UNF Set Screw.
May include an adjuster to alter the length of the webbing. Either rotates in the direction of the load ( with the use of a shouldered spacer) or is fixed in the direction of the load. A Snap Hook for quick release, from an eye bolt, is used in some applications.

Used to secure the Seat Belt to the (PreDesignated) Anchorage Points on the vehicle generally by means of 7/16" UNF Set Screws. Found in End Brackets or other components i.e. the Retractor, Pillar Loop, Buckle etc.

Fittings i.e. set screws, nuts, washers, brackets etc. used to connect the Seat Belt via its Anchorage Holes to the (PreDesignated) Anchorage Points.

(PreDesignated) Anchorage Points are the points on the vehicle to which the Seat Belt is attached.
They are fabricated by the vehicle manufacturer to help absorb the loads in an accident and position the Seat Belt correctly.
The strength and position of () Anch
orage Points is independently approved.
A metal guide that helps the webbing flow in the correct position. Generally only included on a Seat Belt with a Retractor.

The section of webbing that passes across the wearer's lap (bone structure at the top of the legs).

The section of webbing that passes across the centre of the wearer's shoulder and chest (bone structure).

Are approximate and are measured from the centre of anchorage holes to mouths of buckles.

Seat Belts and the anchorage points to which they are fitted should be approved. A Seat Belt should be clearly marked to indicate that it is Approved to an Internationally recognised Standard i.e.
'E' (Economic Commission for Europe Regulation 16) FURTHER INFORMATION

A device attached to or incorporated in some Seat Belt systems at the Retractor or Buckle. Intended to help reduce any webbing slack in the event of an accident. They are NOT a requirement of the Seat Belt Standards and many systems, including Securon's, do not use them. GUIDANCE ON DEACTIVATION

Attached to some Seat Belt systems at the Retractor or Buckle. Intended to help provide a warning and or help control a Pretensioner. They are NOT part of the Seat Belt Standards and many systems, including Securon's, do not use them.