Power Tool Protective Cover with Automatic Depth Locking

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Solution Overview

Problem

Existing covering devices for power tools require constant operator contact pressure to overcome spring force, leading to inadequate cutting depth and increased risk of injury due to the need to pivot the guide carriage without releasing one hand.

Innovation Solution

Incorporation of a latching hook on the depth stop with adjustable locking means that can be displaced into a passive position against the spring force, allowing for automatic fixation of the guide body at a set machining depth, reducing operator contact pressure and enabling convenient depth adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring force is used to bias the guide carriage away from the protective hood, then the guide carriage can be automatically pressed against the workpiece to ensure good protection and optimized suction conditions, but the operator has to exert permanent contact pressure to overcome the spring force, leading to increased operator effort and potential injury risk

Engineering Contradiction:
Improveprotection effectivenessVSAvoidoperator effort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The guide carriage is designed to automatically press against the workpiece using spring force without requiring continuous operator intervention. The system serves itself by maintaining contact pressure through the spring mechanism, eliminating the need for the operator to constantly apply force.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring force is pre-loaded to automatically press the guide carriage against the workpiece before operation begins. This preliminary action ensures that the protective hood is properly positioned and sealed before the operator starts working, reducing the need for continuous adjustment.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the guide carriage is firmly pressed against the workpiece to achieve complete coverage and good protection, then dust extraction effectiveness is improved, but the operator cannot see the tool when the tool device is attached, increasing the risk of injury

Engineering Contradiction:
Improvedust extraction effectivenessVSAvoidinjury risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The guide carriage is designed to be dynamically adjustable, allowing the operator to pivot it away from the workpiece when tool visibility is needed and automatically return to the pressed position when spring force engages. This dynamic positioning enables the operator to see the tool when necessary while maintaining protective coverage during operation.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the depth stop is provided with locking means that require manual engagement, then the machining depth can be adjusted, but the adjustability is inconvenient and requires one-handed operation

Engineering Contradiction:
Improvedepth adjustabilityVSAvoidadjustment convenience
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The locking means on the depth stop are designed to automatically engage with the housing part when the guide carriage reaches the predetermined cutting depth. This self-locking mechanism eliminates the need for manual engagement, allowing the operator to adjust the depth with one hand while the system automatically secures the position.

Inventive Principle:
Principle #25Self-service

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

Facilitates convenient setting and maintenance of desired machining depth with reduced operator effort, ensuring effective protection and optimized dust extraction by automatically fixing the guide body at maximum depth, thus lowering the required contact pressure and enhancing safety.

Implementation Method 1

against the spring force of a locking spring

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

The guide body 18 is biased away from the hood body 8 by a torsion spring 20 in the direction of a first pivoting direction S1

Methodology Applied
Scientific EffectTorsion spring force: Torsion Spring

Data Source

PatentEP1777047B1Protective cover
Publication Date: 2013.11.20 HILTI AG
  • EP1777047B1 patent drawingFigure 1
  • EP1777047B1 patent drawingFigure 2~3
  • EP1777047B1 patent drawingFigure 4

AI summary

A cover device (2) for a tool device (4) for driving a circular disk-shaped tool (6) comprises a hood body (8) that encloses the tool (6), a guide body (18) that can be placed against a workpiece (28) to be machined, which is pivotably mounted on the hood body (8) and is biased away from it in a first pivot direction (S1) by a spring force, and an adjustable depth stop (30) by means of which the guide body (18) can be placed against the hood body (8) in a second pivot direction (S2) opposite to the first pivot direction (S1). A locking device (38) is provided by means of which the guide body (18) can also be adjusted and locked relative to the hood body (8) in the direction of the first pivot direction (S2).