Dust Filter Bag Helical Spring Design to Reduce Closure Deformation
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Solution Overview
Problem
Existing dust filter bag designs face issues with high forces causing plastic deformations during insertion into vacuum cleaners, leading to incomplete closure and increased manufacturing costs due to complex spring structures and expensive materials.
Innovation Solution
A dust filter bag with a helical spring that is loaded about a bending axis at an angle to its longitudinal axis, providing a degressive force characteristic to reduce forces on the closure flap system and avoid plastic deformations, and is manufactured as a cost-effective one-piece injection molded part with a film hinge and rubber-elastic sealing plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a band-shaped spring element or leaf spring is used to hold the closure flap in a closed position, then the closure flap can be kept closed, but large forces occur during insertion which cause plastic deformations in the mounting of the spring element
Solution Approach 1:
The patent changes the spring characteristic from linear (band spring) or constant (leaf spring) to degressive by using a helical spring with specifically designed geometry. The degressive force characteristic reduces the maximum force during insertion while maintaining sufficient closing force, preventing plastic deformations in the mounting.
2Reliability
If a leaf spring with camber is used to hold the closure flap closed, then the closure flap can be kept closed, but a relatively high force must be applied to open the closure flap and the retaining plate must be designed to be very stable
Solution Approach 1:
The patent modifies the spring force characteristic to degressive, which provides high closing force for reliability but reduces the force required to open the flap. The helical spring's geometry allows it to deliver maximum force when compressed (keeping flap closed) but requires less force to extend (opening flap).
3Reliability
If a ribbon spring is strongly prestressed to maintain closure, then the closing force is maintained, but the bending angle is limited and the prestressing is reduced by plastic deformations
Solution Approach 1:
The patent uses a helical spring instead of a ribbon spring, allowing for controlled prestressing without limiting the bending angle. The helical geometry provides a degressive force characteristic that maintains closing force while accommodating the full range of motion without plastic deformations.
4Reliability
If different variants of spring elements with bending axis at an angle to rotation axis are used, then the closure flap can be held closed, but they are relatively expensive to manufacture
Solution Approach 1:
The patent uses a helical spring with the bending axis aligned with the hinge axis of the closure flap, simplifying the mechanism compared to springs with bending axes at angles. This alignment, combined with the degressive force characteristic, maintains closure reliability while reducing manufacturing complexity and cost.
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
The solution ensures reliable closure of the dust filter bag without plastic deformations and reduces manufacturing costs by using a degressive spring force and a simple, cost-effective design.
Implementation Method 1
The spring is formed as a helical spring having a longitudinal axis coaxial with the coils of the helical spring. The helical spring has a first longitudinal section in its extension along the longitudinal axis, which is supported on the retaining plate and that it has a second longitudinal section, which is supported on the closing flap.
Implementation Method 2
The support and arrangement of the helical spring is designed such that when the closure flap is pivoted, the helical spring is loaded about a bending axis which is arranged at an angle, preferably at a right angle, to the longitudinal axis of the helical spring.
Data Source
Figure 1
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AI summary
A dust filter bag (1) for use in a vacuum cleaner is described, comprising a bag (11) made of filter material, a holding plate (12) and a closure flap (13) which is attached to the holding plate (12) via a hinge (13f) about a hinge axis is pivotally mounted in such a way. The closure flap (13) is urged into the closed position by a spring (14), in that the spring is supported with a first end on the closure flap (13) and with a second end on the retaining plate (12). It is essential that the spring is designed as a helical spring (14) with a longitudinal axis running coaxially to the helical windings of the helical spring (14) and the support and arrangement of the helical spring (14) is designed in such a way that when the closing flap (13) is pivoted, the helical spring (14) is loaded about a bending axis (14b) which is arranged at an angle, preferably at right angles, to the longitudinal axis of the coil spring (14).