Crowd Control Barrier Holder Assembly Spring Pre-load Mechanism
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Solution Overview
Problem
Existing crowd control barriers face challenges in easily changing decorated webbing straps onsite, maintaining pre-load tension in springs for proper operation, and accommodating misalignment between posts, which can lead to slack bands and jamming issues.
Innovation Solution
A holder assembly with a rotatably mounted bobbin and spring carrier, utilizing screw-thread means to pre-load the spring upon bobbin insertion, and a flexible tension member to manage tension release and retraction, along with a floating bearing to accommodate misalignment, allowing easy band attachment and detachment without requiring specific skills.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the webbing strap is made changeable to allow on-site decoration changes, then adaptability is improved, but device complexity increases due to the need for removable bobbin and spring mechanism
Solution Approach 1:
The barrier mechanism is divided into separable components: the bobbin (with webbing strap) can be independently removed from the post assembly, and the spring mechanism is contained within the post. This segmentation allows the webbing strap to be changed by simply removing and replacing the bobbin, while the spring mechanism remains intact and automatically re-engages.
Solution Approach 2:
The spring is pre-loaded onto the bobbin during assembly, storing potential energy that automatically winds the webbing strap when the bobbin is reinserted into the post. This preliminary action eliminates the need for manual spring tensioning during strap changes, reducing complexity for the user.
2Manufacturing precision
If pre-load is incorporated during initial assembly, then manufacturing precision is improved, but ease of operation deteriorates when strap changes are required
Solution Approach 1:
The spring is pre-loaded onto the bobbin during initial assembly with precise tensioning, ensuring correct pre-load is achieved once. This preliminary action stores the necessary potential energy in the spring, which then automatically winds the webbing strap during subsequent strap changes without requiring user intervention for tensioning.
Solution Approach 2:
The spring mechanism automatically performs the winding function when the bobbin is reinserted into the post after strap replacement. The stored potential energy in the spring self-activates to wind the webbing strap, eliminating the need for user skill in tensioning or adjusting the mechanism.
3Ease of operation
If the spring energy is released without load, then ease of operation is improved for strap removal, but reliability deteriorates due to spring damage
Solution Approach 1:
The bobbin acts as an intermediary between the spring and the external environment. When the bobbin is removed from the post, the spring's potential energy is gradually transferred to wind the webbing strap onto the bobbin itself, rather than being released uncontrollably. This controlled energy transfer through the bobbin intermediary prevents spring damage while allowing easy strap removal.
4Reliability
If the webbing strap is fully retracted with pre-load, then reliability is improved for barrier function, but device complexity increases to maintain constant tension
Solution Approach 1:
The pre-loaded spring automatically maintains tension on the webbing strap throughout its operational cycle. When the barrier is deployed and the webbing strap extends, the spring's potential energy converts to kinetic energy, automatically winding the strap back onto the bobbin when released. This self-service mechanism ensures consistent tension and reliable barrier function without requiring additional active control systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables easy on-site change of webbing straps, maintains consistent tension, and ensures the band remains flat and unwinds smoothly, reducing the likelihood of jamming and improving usability across uneven surfaces.
Implementation Method 1
a spring arranged to act on the bobbin such that tension in the spring is increased as the band is extended
Implementation Method 2
the assembly includes screw-thread means arranged so that on the axial insertion of the bobbin into the container, the carrier is rotated to pre-load the spring
Data Source
Figure 1
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AI summary
A holder assembly for a crowd control barrier has a bobbin 13 rotatably mounted within a container 12 and configured to have a flexible band 15 wound therearound with the free end 16 of the band emerging from the container whereby the band may be extended so that the free end can be connected to a remote support. When assembled, a spring 25 acts on the bobbin 13 such that tension in the spring is increased as the band 15 is extended whereby the spring may re-wind the band on to the bobbin. The bobbin 13 is axially insertable into and removable from the container 12 to allow the band to be changed. The spring 25 is associated with a carrier 24 and there is a screw-threaded mechanism 27 arranged to rotate the carrier 24 to pre-load the spring 25, as the bobbin 13 is inserted into the container 12.