Feed Delay Device Prevents Guide Channel Blockage

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Solution Overview

Problem

Existing tools for driving fasteners into substrates often face the risk of guide channel blockage due to multiple fastening elements being transported simultaneously, leading to inefficiencies and potential jams.

Innovation Solution

A tool with a feed delay device that ensures fastener transport into the guide channel is delayed until the piston has returned to its initial position after a driving operation, featuring a release and blocking position for the feed delay device, a detection system to verify piston position, and a combustion chamber mechanism that only collapses when the piston is in the initial position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the feed device transports fasteners into the guide channel immediately after piston retraction, then the productivity is improved, but the guide channel may become blocked by multiple fasteners

Engineering Contradiction:
Improvefastener transport speedVSAvoidguide channel blockage risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The feed delay device is actuated in advance by the piston during its retraction stroke, causing the lever to move to the blocking position before the fastener transport begins. This preliminary action ensures that fasteners are fed into the guide channel only after the piston has fully retracted and the blocking lever has returned to the release position, preventing multiple fasteners from entering simultaneously and blocking the channel.

Inventive Principle:
Principle #10Preliminary action

2Speed

If the piston moves back and forth rapidly, then the operating speed is improved, but the risk of multiple fasteners entering the guide channel simultaneously increases

Engineering Contradiction:
Improvepiston reciprocation speedVSAvoidguide channel blockage risk
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The feed delay device functions as a feedback mechanism that responds to the piston's position. The piston's retraction movement automatically actuates the feed delay device through mechanical connection, which in turn controls the timing of fastener transport. This feedback loop ensures that fastener feeding is synchronized with piston position, preventing blockages even during rapid reciprocation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The feed delay device acts as an intermediary between the piston and the fastener transport mechanism. It receives motion from the piston and translates it into controlled timing for the fastener feed, decoupling the direct connection between piston speed and fastener transport timing. This intermediary function allows rapid piston movement while maintaining reliable fastener feeding timing.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3083150B1Work device
Publication Date: 2017.08.16 HILTI AG
  • EP3083150B1 patent drawingFigure 1
  • EP3083150B1 patent drawingFigure 2
  • EP3083150B1 patent drawingFigure 3

AI summary

The invention relates to a work tool for driving a securing element into a substructure, comprising: a guide channel for said securing element; a piston (8) which can be pushed towards said securing element proceeding from a starting position in which the piston (8) is at rest, so as to transmit energy to said securing element arranged in the guide channel; a feed device for conveying the securing element into said guide channel; and a feed-delay device for delaying said securing element being conveyed into the guide channel until the piston (8) has returned into the starting position following a driving process.