Torque-Prone Screw Element for Anchor Expansion
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Solution Overview
Problem
Existing expansion anchors lack sufficient anchoring force and efficiency in expanding the expansion sleeve within the anchor base, leading to suboptimal anchoring properties.
Innovation Solution
The use of a torque-prone screw element on the rear thread of the anchor shank, which transmits greater torque to the anchor shank initially to rotate it relative to the expansion body, ensuring initial expansion and subsequent axial movement to enhance anchoring, combined with an abutment for axial support and anti-rotation elements to facilitate claw penetration and engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional nut is used on the rear thread of the anchor shank, then the device complexity is reduced, but the anchoring force and expansion efficiency are insufficient
Solution Approach 1:
The screw element is divided into functionally distinct sections: a first section with high friction coefficient (torque transmission zone) and a second section with low friction coefficient (expansion zone). This segmentation allows different portions of the screw element to perform different functions - the first section transmits torque to rotate the anchor shank, while the second section allows smooth axial movement for expansion.
Solution Approach 2:
Different sections of the screw element have different local properties - the first section has high friction characteristics for torque transmission, while the second section has low friction characteristics for enabling axial movement. This local differentiation of properties solves the contradiction by providing the right friction characteristics at the right locations.
2Productivity
If the anchor shank rotates relative to the expansion body during expansion, then the expansion efficiency and anchoring are improved, but the torque transmission requirements increase
Solution Approach 1:
The screw element is segmented into a first section for torque transmission (high friction) and a second section for axial movement (low friction). This segmentation enables the system to generate sufficient torque for rotation while allowing smooth axial expansion movement.
Solution Approach 2:
The screw element transitions from a static friction connection in the first section to a dynamic low-friction connection in the second section, allowing the system to adapt friction characteristics during the expansion process - high friction initially for torque, then low friction for axial movement.
3Power
If the friction coefficient between the screw element and anchor shank is increased, then the torque transmission is improved, but the axial movement during expansion is hindered
Solution Approach 1:
The screw element is divided into two sections with different friction coefficients - the first section has high friction for torque transmission, while the second section has low friction for axial movement during expansion.
Solution Approach 2:
Different sections of the screw element have different local friction properties - high friction in the first section for power transmission, low friction in the second section for ease of axial movement.
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 achieves improved anchoring by ensuring the expansion sleeve expands sufficiently and the claws effectively engage with the anchor base, enhancing the anchoring force and stability of the expansion anchor.
Implementation Method 1
The torque-prone screw element on the rear thread of the anchor shank, which transmits greater torque to the anchor shank initially to rotate it relative to the expansion body
Implementation Method 2
The expansion body pushes the expansion segments outwards, i.e. it expands the expansion sleeve
Implementation Method 3
the claws of the expansion segments create undercuts in the wall of the hole, which the claws of the spread-out sleeve engage behind
Implementation Method 4
The expansion sleeve is expanded so far that the conical outer surfaces of the expansion segments are in contact with the hole wall over their entire length or over their entire surface. The expansion anchor is anchored in the hole, with both the expansion segments pressed outwards against the hole wall by the expansion body by frictional engagement on the hole wall
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to an expanding anchor (1) with an anchor shaft (2) that has a rear thread (3) onto which a torque-related nut (6) is screwed, a front thread (4) onto which an expanding body (7) is screwed, and an expanding sleeve (8) which is axially supported on a counter bearing (10) of the anchor shaft (2). The nut (6) on the rear thread (3) is friction- and torque-related so that the anchor shaft (2) rotates with the nut (6) at the start of an expansion of the anchor shaft (2), the front thread (4) draws the expanding body (7) into the expanding sleeve (8), and said sleeve expands. If a torque increases during the expansion, the nut (6) begins to rotate on the rear thread (3) and exerts a pull on the anchor shaft (2), whereby the expanding sleeve (8) is moved in the longitudinal direction in addition to expanding. Claws (14) of the expanding sleeve (8), said claws protruding outwards, are thereby not just pressed into a perforated wall, but rather said claws also move in the longitudinal direction, thus facilitating the pressing. The expanding anchor (1) creates an undercut behind which said anchor engages, thereby improving the anchoring of said anchor.