Manual Tacker Spring Fatigue Prevention

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Hand-held tackers with drive springs experience fatigue due to prolonged tensioning when not used, leading to potential energy wastage and reduced lifespan, especially when scaled for higher driving energies.

Innovation Solution

Incorporating an additional switching mechanism, such as a timer or main switch, to automatically release the drive spring into a relaxed state if not actuated within a preset time, ensuring controlled energy dissipation and preventing malfunctions during use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the drive spring is tensioned for prolonged periods when not in use, then the driving energy is maintained ready for operation, but the drive spring experiences fatigue leading to reduced lifespan and potential failure

Engineering Contradiction:
Improvedriving energyVSAvoiddrive spring lifespan
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The blocking device is pre-configured to automatically engage and block the driving ram after a predetermined time period following the last actuation. This preliminary action prevents prolonged tensioning of the drive spring without requiring active monitoring or user intervention, thereby resolving the contradiction between maintaining readiness and preventing fatigue.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system employs a self-regulating mechanism where the blocking device automatically extends or retracts based on time elapsed since last use. When the predetermined time is exceeded, the blocking device autonomously engages to release tension on the drive spring, eliminating the need for external control systems and enabling the system to self-manage its own reliability.

Inventive Principle:
Principle #25Self-service

2Reliability

If a manual release switch is used to transfer the blocking device to release position, then the drive spring can be relaxed, but the device requires additional user action and may be forgotten leading to continued tensioning

Engineering Contradiction:
Improvedrive spring fatigue preventionVSAvoiduser operation complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The blocking device automatically performs the function of releasing the drive spring tension after the predetermined time period without requiring any user action. The system monitors its own usage state and autonomously engages the blocking mechanism, eliminating the need for users to remember or manually operate a release switch.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the manual mechanical operation of a release switch with an automatic time-based mechanical system. The blocking device uses a time-measuring mechanism (such as a spring-loaded timer or rotational indicator) that automatically triggers the blocking action, substituting user-dependent manual operation with an autonomous mechanical timing system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the blocking device is transferred to release position during work sessions, then the drive spring relaxes, but this causes malfunctions and interrupts the working process

Engineering Contradiction:
Improvecontinuous working capabilityVSAvoiddrive spring energy dissipation
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The blocking device is designed to engage only after the predetermined time period has elapsed since the last actuation. This preliminary timing action ensures that during active work sessions (within the predetermined time), the blocking device remains disengaged and does not interfere with the driving ram or cause energy loss, while still preparing to protect against fatigue once the time threshold is exceeded.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The blocking device employs a dynamic design where its state (blocked or released) changes based on the timing condition. During active use within the time window, the device remains in a released state allowing full driving energy transmission. After the predetermined time, it dynamically transitions to the blocked state to prevent fatigue, automatically adapting to the operational phase without interrupting ongoing work.

Inventive Principle:
Principle #15Dynamics

4Power

If the drive spring is scaled for higher driving energies, then the driving capability is improved, but the risk of fatigue and failure increases proportionally

Engineering Contradiction:
Improvedriving energyVSAvoidfatigue risk
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The blocking device implements a preliminary protective action by automatically limiting the duration of tensioning to the predetermined time period. This pre-established time limit prevents the drive spring from remaining under high tension indefinitely, thereby counteracting the increased fatigue risk that comes with scaling up to higher driving energies before fatigue can occur.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The system provides beforehand protection against fatigue by implementing the automatic blocking mechanism that activates after the predetermined time period. This cushioning effect protects the high-energy drive spring from excessive and prolonged stress accumulation, allowing the system to safely operate at higher energy levels without proportionally increased failure risk.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP1927436B1Manually operated fastener driving device
Publication Date: 2016.11.02 HILTI AG
  • EP1927436B1 patent drawingFigure 1
  • EP1927436B1 patent drawingFigure 2

AI summary

The manual tacker has a tack plunger (13) movable into a guiding (12) and drivable by a drive spring element. A tightening device (70) or the drive spring element are provided for the plunger. A locking device (50) is provided by which the plunger and the drive spring element are locked in a locked position and in a tightened position. Another switching unit is provided for the locking device, by which the locking device is transferable independently from the operating switch (19) into the release position.