Knock-out Sleeve Longitudinal Ribs for Installation Pipe Misinsertion

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Solution Overview

Problem

Existing installation parts for electrotechnical purposes, such as installation boxes for concrete construction, often lead to incorrect installations due to the lack of clear differentiation between knock-out sleeves and installation pipes, resulting in improper usage and potential damage during injection molding processes.

Innovation Solution

Incorporating longitudinal ribs on the knock-out sleeve to prevent incorrect insertion of installation pipes and providing additional features like insertion depth limiting stops and tie projections to assist in correct installation and pipe positioning, ensuring proper usage and enhanced injection molding efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a knock-out sleeve is provided without additional features, then the injection molding process is simple and fast, but incorrect installation occurs when users slide installation pipes onto the sleeve instead of knocking it out

Engineering Contradiction:
Improveinstallation correctnessVSAvoidknock-out sleeve structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The knock-out sleeve is designed with longitudinal ribs that create an asymmetric profile. This asymmetric structure prevents symmetric insertion of installation pipes, as the ribs protrude radially beyond the sleeve surface to a extent that blocks pipe insertion while allowing hammer access to the flat end face for knocking out the sleeve.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The knock-out sleeve has different surface characteristics at different locations: the lateral surface has protruding longitudinal ribs that prevent pipe insertion, while the end face has a flat surface that accepts hammer blows for knocking out. This local differentiation of surface properties enables the sleeve to simultaneously prevent incorrect installation and allow correct removal.

Inventive Principle:
Principle #3Local quality

2Reliability

If longitudinal ribs are added to the knock-out sleeve to prevent incorrect installation, then installation correctness improves, but the injection cycle may be delayed due to unfavorable cooling

Engineering Contradiction:
Improveinstallation correctnessVSAvoidinjection cycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The longitudinal ribs are designed to run continuously from the opening of the knock-out sleeve to the knock-out wall part, ensuring that the cooling effect is established early in the injection molding process. This preliminary structuring of the cooling paths allows efficient heat dissipation throughout the rib structures, preventing injection cycle delays.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the longitudinal ribs are molded onto the knock-out sleeve, then the ribs provide better cooling during injection molding, but the ribs may interfere with the knocking out process

Engineering Contradiction:
Improveinjection speedVSAvoidknocking out process
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The longitudinal ribs are segmented into discrete structures that are molded onto the knock-out sleeve. These segmented ribs provide cooling surfaces during injection molding but are positioned and sized such that they do not interfere with the knocking out process, as the flat end face of the sleeve remains accessible to hammer blows.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If no insertion depth limiting means are provided, then the device structure remains simple, but installation pipes with smaller diameter may be inserted too far into the installation part

Engineering Contradiction:
Improveinsertion depth accuracyVSAvoidholding means structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The holding means are designed to automatically engage with installation pipes of smaller diameter at predetermined breaking points. This self-engaging mechanism provides insertion depth control without requiring additional active components or complex control systems, as the structural design itself enforces the depth limitation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2128948B1Installation part
Publication Date: 2011.05.04 KAISER AKTIENGES
  • EP2128948B1 patent drawingFigure 1~2
  • EP2128948B1 patent drawingFigure 3
  • EP2128948B1 patent drawingFigure 4

AI summary

The part (1) has a hollow-cylindrical support (2) provided at walls (5, 6), where the support is provided for insertion of curved installation pipes. A deflection sleeve (8) is provided with two longitudinal ribs (9). The longitudinal ribs are projected around a measure radially from the stop sleeve such that the plugging of the installation pipes is prevented on the deflection sleeve. A retaining unit is connected with a wall part (7) via a predetermined breaking point. The installation pipes are provided with a diameter dimension of 20 millimeters to 25 millimeters.