Plasterboard Fixing Fingers With Radial Expansion in Thin Cavities
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fixing devices for plasterboards are inefficient due to the need for lengthy insertion and complex multi-part designs, which increase installation time and cost, and are not suitable for close spacing to brick walls, especially when the plasterboard is adhered with batons or adhesive, limiting their use in plasterboard cavity walls.
Innovation Solution
A fixing device with two or more contra-rotating 90-degree fingers that expand radially when inserted into a pre-made hole, mechanically locking in place with a screw, allowing for a short axial protrusion past the plasterboard, and utilizing a central hub for simultaneous or sequential insertion to maximize space within the board thickness for expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fixing devices are used that require lengthy insertion past the rear surface of plasterboard, then secure anchoring is achieved, but installation time increases and the fixing cannot be used when plasterboard is closely spaced from brick walls
Solution Approach 1:
The fixing device is divided into multiple fingers (typically three) that can expand independently within the plasterboard thickness. Each finger has engagement features that distribute the anchoring function across multiple points, allowing secure fixation without requiring deep insertion past the rear surface. The segmented finger structure enables radial expansion confined within the board thickness.
Solution Approach 2:
The fixing mechanism transitions from axial insertion depth to radial expansion within the board plane. Instead of achieving anchoring by traveling deep axially past the rear surface, the fingers expand radially outward within the plasterboard thickness, utilizing the lateral dimension to create secure engagement with the board material.
2Reliability
If conventional two-stage fixing devices are used that require mechanical expansion by rotating a screw or using special installation tools, then board gripping expansion is achieved, but installation time increases and device complexity increases
Solution Approach 1:
The insertion and expansion functions are merged into a single operation. The fingers are designed to automatically expand radially as they are inserted into the pre-drilled hole, eliminating the need for a separate expansion stage. The engagement features on the fingers cause them to splay outward during insertion, achieving board gripping without additional tools or screw rotation.
Solution Approach 2:
The fixing device performs its own expansion function during insertion without requiring external tools or additional operational steps. The geometry of the fingers and their engagement features causes automatic radial expansion as the fingers are driven into the hole, making the system self-actuating and eliminating the need for special installation tools.
3Reliability
If conventional fixing devices with multiple parts are used, then functional requirements are met, but production cost increases
Solution Approach 1:
Multiple functional components that would traditionally be separate parts (fingers, expansion elements, engagement features) are merged into a single integrated fixing device. The device can be manufactured as one piece using processes like injection molding, eliminating the need for assembly of multiple components and reducing production complexity and cost.
Solution Approach 2:
The single-piece fixing device performs multiple functions simultaneously: insertion, radial expansion, board engagement, and load bearing. By consolidating these functions into one component rather than requiring separate parts for each function, the device reduces manufacturing steps and assembly operations.
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
This solution reduces installation time and cost by allowing for efficient expansion within the plasterboard thickness, suitable for close spacing to brick walls, and provides a low-part-count design that can be made from various materials, ensuring secure anchoring with minimal protrusion past the plasterboard.
Implementation Method 1
two or more contra-rotating 90 degree fingers which when pressed into a pre made hole within the plasterboard engage to rotate and expand radially
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fixing device (101) has a pair of complementary fingers (102,103) complementary pivot formations (121,122). Each has distal portion (104) and a proximal portion (105). Both have a flat surface (106), which abuts the same face in the other finger, both at the distal portions when the fixing is arranged for insertion in an aperture (107) in a board (108) and at the proximal portions when the fingers are arranged both for insertion and gripping of the board. The distal portions each have a surface (111) with an edge (1112) common with the surface (106). This surface (111) comes into abutment with the back face (112) of the board (108). The proximal portion is generally hemispherical to allow rotation within the aperture (107). A lug portion (1161) generally in the direction of the distal portion (104). With the fingers engaged and their distal portions brought as close to alignment as possible, the Tee projections (114) abut the flanges (109) at angled faces (135). The contours of the fingers are such that they can be inserted into the aperture (107) until the distal portions (104) enter the aperture. Passage of these through the aperture is inhibited by the lugs (1161), specifically by abutment of the angled back surface (118). Pressure on the angular relief surfaces (120) of the abutments (1162) urges the lugs into the front face (135) of the board (108). The reaction of the board acts about the pivot centrally of the aperture, tending to turn the fingers about the lugs under the constraint that they are pivoted together. The fingers are turned with the distal portions coming to lie on the backside of the board. This allows the fastener (130), typically a self-tapping screw to be inserted between the complementary recesses (134), where they open in the outer surfaces (117).