Concrete Screw With Integrated Adhesive Dispensing Piston

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Solution Overview

Problem

Existing self-tapping screws face challenges in achieving easy and reliable setting with high load values, particularly in concrete substrates, often requiring complex adhesive dosing and separate mortar introduction processes.

Innovation Solution

A self-tapping screw design featuring an extrusion piston and a mass reservoir containing a hardenable compound, where the piston presses out the adhesive between the shaft and the borehole wall as the screw is inserted, eliminating the need for separate adhesive application and simplifying the setting process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate adhesive application process is used, then adhesive can be applied to the borehole wall, but the installation process becomes complex and time-consuming

Engineering Contradiction:
Improveadhesive application reliabilityVSAvoidinstallation process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the adhesive application function with the screw installation process by integrating an adhesive reservoir and dispensing piston into the screw body. The adhesive is dispensed automatically during screw insertion, merging two separate operations (adhesive application and screw installation) into one unified process, thereby reducing installation complexity while maintaining reliable adhesive application

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The screw performs the adhesive application function itself through its integrated dispensing piston and reservoir system. During installation, the screw's own advancement into the borehole automatically triggers the dispensing of adhesive, eliminating the need for external adhesive application equipment or separate dosing steps, thus simplifying the overall installation process

Inventive Principle:
Principle #25Self-service

2Reliability

If adhesive is applied manually before screw insertion, then adhesive can be positioned in the borehole, but the installation time increases and productivity decreases

Engineering Contradiction:
Improveadhesive positioning accuracyVSAvoidinstallation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The adhesive is pre-loaded into the reservoir in a controlled manufacturing environment, ensuring proper positioning and quantity. During installation, this pre-positioned adhesive is automatically dispensed at the correct location as the screw advances, combining the benefits of pre-positioning accuracy with rapid installation speed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The adhesive dispensing occurs continuously during the screw insertion process itself. As the screw advances into the borehole, the dispensing piston continuously dispenses adhesive along the screw shank, eliminating idle time between adhesive application and screw installation, thereby maintaining continuous productive action throughout the setting process

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If a defined quantity of adhesive is provided, then adhesive dosing accuracy improves, but additional dosing equipment or complex mechanisms are required

Engineering Contradiction:
Improveadhesive dosing precisionVSAvoiddosing mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The screw itself serves as the dosing mechanism through its integrated reservoir and dispensing piston. The geometry of the reservoir and piston design inherently controls the adhesive quantity dispensed, eliminating the need for external dosing equipment or complex electronic control systems, thus achieving precise dosing through simple mechanical means

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The adhesive dosing is controlled by the physical parameters of the reservoir volume and piston displacement. By designing the reservoir capacity and piston travel distance, the exact quantity of adhesive is determined through geometric parameters rather than complex dosing mechanisms, simplifying the overall system while maintaining dosing precision

Inventive Principle:
Principle #35Parameter changes

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 design enables a strong, reliable glued connection with high load values and simplifies the setting process by automatically applying the adhesive, reducing manufacturing effort and operational complexity.

Implementation Method 1

the dispensing piston moves closer to the shank during screw insertion. This reduces the volume between the dispensing piston and the shank, thus squeezing out the compound reservoir located between the piston and the shank

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

In particular, this is a curable compound that preferably hardens after flowing between the shaft and the borehole wall

Methodology Applied
Scientific EffectCuring: Phase Change

Data Source

PatentEP3126682B1Screw with pressing piston
Publication Date: 2019.03.06 HILTI AG
  • EP3126682B1 patent drawingFigure 1~4
  • EP3126682B1 patent drawingFigure 5~8

AI summary

The invention relates to a screw, in particular a concrete screw, having a shaft (110, 410) that has a front end for introduction into a borehole in a substrate and a rear end, and at least one thread coil (111, 411) that is provided on the shaft. According to the invention, the screw has an extrusion plunger (130, 230, 330, 430) which is provided in front of the front end of the shaft, a compound reservoir (160, 460) being provided between the extrusion plunger and the shaft.