Expandable Bolt Unit for Watertight Fixing in Soft Drilled Holes
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Solution Overview
Problem
Existing bolt units for fixing objects to soft construction structures like asphalt roads are prone to separation due to impact and water leakage, requiring multiple drilled holes and extensive installation time.
Innovation Solution
A multi-purpose bolt unit with a cylindrical body, elastic packing pipe, washers, and a compression nut that expands the packing pipe for watertight sealing and secure fixation, featuring friction protrusions and a fastening screw groove for anchor bolts, allowing universal application across varying drilled hole diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple anchor bolts and metal screws are used to fix objects to drilled holes in soft construction structures, then the fixation strength is improved, but the device complexity and installation time increase
Solution Approach 1:
The patent combines multiple separate components (cylindrical body, elastic packing pipe, compression nut, washer) into an integrated bolt unit system. The cylindrical body houses both the anchor bolt and elastic packing pipe, merging the fastening and sealing functions into a single unified structure that reduces overall system complexity while maintaining fixation strength.
Solution Approach 2:
The bolt unit is designed as a universal multi-purpose fixture that can be applied to various objects (elastic poles, parking stoppers, signs) and different soft construction structures (asphalt roads, parking lots). The standardized cylindrical body with interchangeable elastic packing pipes allows one design to serve multiple functions across different applications, reducing the need for multiple specialized fastening systems.
2Reliability
If multiple drilled holes are formed to fix objects to soft construction structures, then the fixation reliability is improved, but the loss of time and installation effort increase
Solution Approach 1:
The elastic packing pipe is pre-installed inside the cylindrical body before the compression nut is tightened. This preliminary positioning ensures that when the compression nut is screwed on, the elastic packing pipe is already in place to expand and seal against the drilled hole wall, eliminating the need for separate sealing steps and reducing overall installation time while maintaining reliable fixation.
Solution Approach 2:
The elastic packing pipe automatically expands and seals the drilled hole when the compression nut is tightened, without requiring additional sealing materials or manual intervention. The elastic material self-adjusts to the hole dimensions and creates a watertight seal through the expansion force generated by the compression nut, making the system self-sealing and reducing installation complexity.
3Strength
If anchor bolts are used to fix objects to drilled holes, then the fixation strength is improved, but the object is prone to separation under repeated impact
Solution Approach 1:
The patent changes the physical state and dimensions of the packing pipe through compression. When the compression nut is tightened, it compresses the elastic packing pipe axially, causing the pipe to expand radially and increase its outer diameter. This parameter change allows the packing pipe to tightly fit against the drilled hole wall, creating friction that resists separation under impact while maintaining strong fixation.
Solution Approach 2:
The bolt unit combines different materials with complementary properties: the cylindrical body provides structural strength, the elastic packing pipe provides sealing and friction resistance, and the compression nut provides adjustable clamping force. This composite structure integrates the advantages of rigid and elastic materials to achieve both strong fixation and resistance to separation under repeated impact.
4Object-affected harmful factors
If drilled holes are exposed due to pulled-out anchor bolts, then water leakage occurs, but using additional sealing components increases device complexity
Solution Approach 1:
The elastic packing pipe serves as an intermediary element between the cylindrical body and the drilled hole wall. It transfers the compression force from the compression nut into radial expansion, creating a sealing interface that prevents water leakage. This intermediary component simplifies the sealing mechanism compared to using multiple separate sealing elements, as the elastic material inherently provides both sealing and friction resistance in a single component.
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 bolt unit maintains secure fixation and watertightness even under impact, reducing the need for multiple drilled holes and simplifying installation, while accommodating varying hole diameters with interchangeable washers and packing pipes.
Implementation Method 1
an elastic packing pipe inserted into the cylindrical body and placed on the front end tip
Implementation Method 2
a plurality of friction protrusions formed in an outer circumferential surface of the elastic packing pipe to increase friction with an inner circumferential surface of the drilled hole
Data Source
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AI summary
Disclosed is a multi-purpose bolt unit for fixing an object to a drilled hole formed in a soft construction structure, the multi-purpose bolt unit including: a cylindrical body inserted into the drilled hole of the soft construction structure; a front end tip formed at a lower end of the cylindrical body and having a larger outer diameter than an outer diameter of the cylindrical body; an upper thread surface formed in an upper side of the cylindrical body while spaced apart from the front end tip; an elastic packing pipe inserted into the cylindrical body and placed on the front end tip; an upper washer inserted into the cylindrical body and placed on an upper end of the elastic packing pipe; a compression nut screwed to the upper thread surface and pressurizing the upper washer so that the elastic packing pipe expands; and a fastening screw groove formed inside the cylindrical body and opened upward through the compression nut.