The size of roller blinds and the bearing capacity of roller tubes

When we purchase roller blinds, suppliers often divide large roller blinds into two or more. We do not want to adopt this solution because due to the influence of the mounting bracket, there will be gaps between each roller blind, which will affect the shading.
In some case sharing, EMLUX mentioned that the width of the raw material of the roller blind fabric will affect the size of the roller blind. This article will share with you the relationship between the size of the roller tube and the roller tube. EMLUX makes your procurement more professional, communicate with Emlux more effectively, and reduce your procurement time.

The size of the roller blind (such as width, height, weight) is closely related to the bearing capacity of the roller tube. When designing, it is necessary to ensure that the roller tube can stably support the operation of the roller blind. The following are key factors and analysis:

1. The impact of roller blind size on the roller tube
Width:
The larger the width of the roller blind, the greater the torque and bending stress of the roller tube. The diameter or wall thickness of the roller tube needs to be increased to improve the bending resistance and avoid deformation.

For example: a 3-meter-wide roller blind requires a stronger material (such as thickened steel pipe or aluminum alloy) than a 1-meter-wide roller tube.

Height/weight:
The higher the roller blind, the heavier the curtain (especially metal), and the roller tube needs to withstand greater radial loads and torsional forces. Considerations:

Curtain material: PVC soft curtains are lighter, aluminum alloy or steel curtains are heavier.

Spring balance system: The torsion of the spring must match the weight of the roller blind, otherwise it will cause the roller tube to be overloaded or unable to rewind normally.

2. Key parameters of the bearing capacity of the roller tube
Material:

Aluminum alloy: light, corrosion-resistant, suitable for small and medium-sized roller blinds (such as homes and shops).

Steel pipe: high strength, suitable for heavy roller blinds (such as industrial warehouses).

Wall thickness: usually 0.8mm~3mm, heavy roller blinds need to be thicker.

Diameter:
The larger the diameter, the stronger the bending resistance. Common diameters are 28mm~100mm, and heavy roller blinds can reach more than 120mm.

Support spacing:
The larger the spacing between the fixed points at both ends of the roller tube (such as the distance between the motor and the bearing), the more you need to increase the pipe diameter or reduce the curtain weight to avoid sagging.

3. Calculation and selection suggestions
Torque calculation:
The torque (T) that the roller tube needs to withstand is related to the weight of the roller shutter (W) and the radius of the roller tube (R):
T ≈ W × R
(need to be combined with the auxiliary torque of the spring system)

Safety factor:
The recommended safety factor for industrial roller shutters is ≥2, that is, the roller tube bearing capacity must be more than twice the actual load.

Professional consultation:
For large or special-purpose roller shutters (such as fire protection and wind protection), it is recommended that the supplier provide mechanical verification, and EMLUX can provide you with mechanical verification.
Below, emlux will analyze the two roller tubes(75mm alumimum tube,78mm iron tube) commonly used in windproof roller shutters to evenly bear 50KG of force at a length of 5 meters.


The above analysis shows that a 75mm aluminum tube will have an 85mm displacement in the middle when it is 5 meters long and bears 50kg. Under the same conditions, a 78mm iron tube will have a 16mm deformation. The aluminum tube has too much deformation and is not suitable for a load of 50kg in a 5-meter situation. Iron tubes can be used under this condition by reducing the load by one-third.
4. Common problems and solutions
Roller tube deformation:
The reason may be that the tube diameter is too small or the material is too thin, and it is necessary to replace the thickened steel tube or shorten the support spacing.

Poor rewinding:
Check whether the spring torque matches the curtain weight, or whether the roller tube is fatigued due to long-term load.

Summary
The size and weight of the roller shutter directly determine the selection of the roller tube. It is necessary to comprehensively consider the material, diameter, wall thickness and support method, and ensure stability through calculation or professional testing when necessary. Ordinary household roller blinds (width <4 meters, lightweight curtains) can use aluminum alloy tubes; industrial scenes (width >5 meters, heavy curtains) require customized steel roller tubes and strengthened supports.

The following are our commonly used aluminum tube load-bearing experience values, using different aluminum tubes within the length range in the table below.
You can also consult EMLUX when placing an order, and we will provide you with a reliable application solution
The following table is the empirical data of EMLUX within the limit range of length. 50mm aluminum tube is used within 3 meters, 63mm aluminum tube is used within 5 meters, and 90mm aluminum tube is used within 6.7 meters.