Vertical blind headrails are made in extruded aluminium which is either anodised or painted. They normally have a plain or ribbed face, however some are available with a recessed front which accepts a piece of louvre fabric. This gives the whole blind a co-ordinated appearance. Components within the headrail are of injection moulded plastic with the exception of the links which control the spacing of the carrier trucks. These can be made of stainless steel or plastic. Operation can be dual control with separate louvres for tilt and traverse or mono controlled through a gearbox. Electrical operation is available. For bay windows, tracks can be curved or joined.

Louvres are normally weighted at the bottom and connected to each other by chains which are fitted near the bottom of the louvres. Alternatively, blinds can be fitted with a bottom rail with controls operating both headrail and bottom rail. Blinds made in this way can be fitted at an angle and are suitable for skylights.

Louvres can be made in a variety of materials. Woven, knitted or non-woven fabrics are used to cut out the glare of sunlight whilst allowing a soft diffused light into the room. Where more light control is needed, for instance in computer rooms, flexible, laminated PVC fabrics are normally specified. Although these can be completely opaque it should be noted that vertical blinds cannot be used when 100% blackout is required. Aluminium or rigid, extruded PVC louvres are also available. Louvres are generally supplied 127mm or 89mm wide although other widths, such as 100mm, 63mm and 50mm, can be supplied. Louvres can be flame-proofed to UK and other standards. They are also available in washable fabrics and special treatments are available to kill MRSA.

Types and operation

• Bunching - left hand or right hand bunch - all louvres bunch on left-hand side or right-hand side when the blind is fully open.
• Split bunch - equal numbers of louvres bunch to each side when the blind is fully open.
• Centre bunch - all louvres bunch in the centre when the blind is fully open.
• Curved blind - blind with the headrail continuously curved to a specific shape to fit a curved window or similar installation. Blinds operated by one set of controls.
• Dual controls - individual controls to operate the traversing and rotation of the louvres.
• Electrical operation - the use of one or two electric motors to operate the traversing and/or rotation of the louvres.
• Free hanging blind - blinds with louvres which are not fixed at the bottom.
• Mono control - use of one control to operate both the traversing and rotation of the louvres.
• Pelmet - a piece of reinforced louvre fabric supported on a bar fixed to the headrail.
• Pitched blind - free hanging blind with the top and/or bottom not horizontal.
• Stepped blind - free hanging blind with a section of the louvres cut to a different length to avoid an obstruction such as a radiator.
• Top & bottom track blind - a blind with the louvres held rigidly between two tracks. Suitable for use on a skylight or any other installation where the louvres are not vertical.

Components

• Headrail - anodised or painted aluminium extrusion.
• Tilt rod - aluminium extrusion used to operate the louvre rotation gearing.
• Fixing brackets - plastic, galvanised or painted mild steel.
• End cap - moulded plastic. Fixed at each end of headrail. Used to support the tilt rod and blind controls.
• Louvre carrier truck - moulded plastic. Incorporates the gearing to rotate the louvre hook.
• Fixed gear truck - truck with a direct drive between the louvre hook and tilting device.
• Self-aligning truck - Self-aligning trucks have limit stops which restrict louvre rotation to 185°.
• Spacer link - stainless steel or plastic. Controls the spacing between the louvre hooks.
• Tilt/rotation chain - metal or cord with plastic balls. Turns the tilt rod to control the louvre rotation.
• Tilt gearbox - a geared drive to adjust the louvre angle.
• Traversing cord - stretch resistant. Used to traverse the carrier trucks.
• Cord weight - moulded plastic. Hooks on to traversing cord to prevent sagging.
• Spring cord tensioner - mild steel. Alternative to cord weight.
• Louvre insert/hanger - plastic. Fixed into top of louvre to connect louvre to the louvre hooks.
• Louvre weight/ballast weight - metal or moulded plastic. Fixed to bottom of louvres to hold fabric under tension.
• Stabilising chain - metal or cord with plastic balls. Fitted to bottom of louvres to prevent excessive movement in draughty conditions.

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