Spring Deactivation for Depth Adjustment in Handheld Cutting Machines

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Solution Overview

Problem

The handling of depth adjustment in hand-held cutting machines, such as pendulum hood saws, is complicated due to the need to grasp both the guide device and the drive assembly simultaneously, making it difficult to set the cutting depth effectively.

Innovation Solution

A spring deactivation device is integrated into the hand-held cutting machine, allowing the drive assembly to automatically adjust to the upper cutting depth position using a return spring, simplifying the operation by loosening the fixation and enabling the machine to function both as a conventional pendulum hood saw and a plunge saw, with the covering device remaining secure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the operator manually adjusts the drive assembly to set cutting depth, then the cutting depth can be set, but the handling becomes complicated requiring simultaneous grasp of guide device and drive assembly

Engineering Contradiction:
Improveease of depth adjustmentVSAvoidcomplexity of depth adjustment mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The drive assembly automatically returns to the upper cutting depth position through the return spring mechanism when the locking element is released, eliminating the need for manual adjustment by the operator. The system serves itself by using the spring force to restore the drive assembly to its default position, thereby simplifying the operation while maintaining the depth adjustment capability.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If the return spring mechanism is always active, then the drive assembly automatically adjusts to upper cutting depth position, but the machine cannot function as plunge saw

Engineering Contradiction:
Improveversatility between pendulum hood saw and plunge saw modesVSAvoidsimplicity of operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The spring deactivation device allows the return spring mechanism to be dynamically deactivated when needed for plunge saw operation. The locking element can be positioned to engage with the return spring mechanism, deactivating it temporarily to enable plunge cutting mode, and then reactivated to enable automatic return to upper cutting depth position for pendulum hood saw mode. This dynamic control provides versatility while maintaining operational simplicity.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the covering device is secured in closed position, then safety is improved, but the cutting tool cannot be accessed for plunge cutting

Engineering Contradiction:
Improvesafety protectionVSAvoidcapability for plunge cutting mode
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The spring deactivation device enables dynamic control of the covering device's closed position securing. When the return spring mechanism is deactivated through the locking element engagement, the covering device can be manually opened to allow plunge cutting access. When activated, the covering device remains securely closed for safety during pendulum hood saw operation. This dynamic mechanism provides both safety and versatility.

Inventive Principle:
Principle #15Dynamics

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 design enhances the convenience and simplicity of operation by allowing the machine to adjust automatically, reducing the complexity of setting cutting depths and enabling easy switching between modes while maintaining safety with a secure covering device.

Implementation Method 1

a return spring mechanism (65) which adjusts the drive assembly (11) in the direction of the upper cutting depth position (SO) when the locking element (81) is released

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3256298B1Manually operated cutting machine comprising a return spring mechanism
Publication Date: 2021.11.03 FESTOOL GMBH
  • EP3256298B1 patent drawingFigure 1~2
  • EP3256298B1 patent drawingFigure 3~4
  • EP3256298B1 patent drawingFigure 5~7

AI summary

The invention relates to a manually operated cutting machine (10), more particularly a power saw, comprising a drive unit (11) which has a tool mount (13) for a disc-type cutting tool (14), more particularly a saw blade, and a drive motor (12) for rotationally driving the tool mount (13), and comprising a guide arrangement (20) which can be guided along a base by way of a guide surface (27) and via which the drive unit (11) is pivotally mounted by means of a depth adjustment bearing (36) to pivot about a depth adjustment axis (TA) between an upper cutting depth position and a lower cutting depth position, wherein in the lower cutting depth position (SU) the tool mount (13) is closer to the guide surface (27) than when in the upper cutting depth position (SO), so that the cutting tool (14) projects further beyond the guide surface (27) than when in the upper cutting depth position, wherein the manual cutting machine has a hood-like cover arrangement (19) which is pivotally mounted to pivot relative to the drive unit (11) between an open position (O) and a closed position (S) so as to cover the cutting tool (14), and which in the open position (O), in order to make a cut in a workpiece (W), releases a part of the cutting tool (14) that projects beyond the guide surface (27), and in the closed position covers the cutting tool (14). The drive unit (11) is biased towards the upper depth adjustment position (SO) by a return spring arrangement (65).