Rotary Rotor Return Mechanism for Fastener Driving Tools

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Solution Overview

Problem

Existing setting devices for driving fastening elements into substrates face inefficiencies in the return mechanism of the driving element, which complicates the resetting process.

Innovation Solution

A setting tool with a rotating rotor and radially movable driver elements that engage with the driving element through centrifugal force, assisted by springs and a separate motor for efficient counter-rotation, simplifies the return process by allowing the driver element to disengage automatically after rotation stops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a rotor with radially movable drive elements is used to reset the driving element, then the return process is simplified and automation is improved, but the device complexity increases due to additional components

Engineering Contradiction:
Improveautomatic engagement and disengagement of drive elementsVSAvoidcomplexity of return mechanism
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The drive elements are designed to engage with the driving element automatically through radial movement during rotor rotation, and disengage automatically when rotation stops, eliminating the need for separate engagement and disengagement mechanisms. The spring-loaded design enables self-actuation based on rotational motion alone

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The drive elements transition from a static radial position to a dynamically movable radial position during rotor rotation. This dynamic adjustment allows the drive elements to engage and disengage based on the rotational state, simplifying the return mechanism while improving automation

Inventive Principle:
Principle #15Dynamics

2Reliability

If multiple drive elements are used on the rotor, then the return mechanism becomes more reliable, but the manufacturing complexity increases

Engineering Contradiction:
Improvereliability of return mechanismVSAvoidmanufacturing of rotor with multiple drive elements
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The return mechanism is divided into multiple identical drive elements distributed around the rotor periphery. Each drive element is a separate, standardized component that can be manufactured independently and assembled onto the rotor, improving reliability through redundancy while maintaining manufacturing simplicity through standardization

Inventive Principle:
Principle #1Segmentation

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 enhances the efficiency and simplicity of the driving element's return to its starting position, reducing mechanical complexity and improving the overall operation of the setting tool.

Implementation Method 1

The return mechanism includes a spring that acts between the rotor and the drive element, biasing the drive element towards the axis of rotation

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

the drive element is radially movable on the rotor with respect to the axis of rotation so that the drive element moves away from the axis of rotation as the rotor rotates

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3898112B1Setting device
Publication Date: 2023.04.12 HILTI AG
  • EP3898112B1 patent drawingFigure 1~2
  • EP3898112B1 patent drawingFigure 3a)~3d)
  • EP3898112B1 patent drawingFigure 4

AI summary

The invention relates to a fastener driving tool for driving fastening elements in a placement direction into a substrate. The fastener driving tool comprises: a driving element, which is movable back and forth between a starting position and a placement position; a drive, which is provided for driving the driving element in the placement direction from the starting position to the placement position, in order to transfer energy to a fastening element; and a return device, which is provided for conveying the driving element counter to the placement direction from the placement position to the starting position. The return device comprises a rotor, which is rotatable about a rotational shaft, and an entraining element, which is attached to the rotor and can be brought into engagement with the driving element in order to entrain the driving element counter to the placement direction. The entraining element is attached to the rotor so as to be radially movable relative to the rotational shaft such that, when the rotor rotates, the entraining element moves away from the rotational shaft in order to come into engagement with the driving element.