Electric Scissors with Adjustable Blade Opening

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Solution Overview

Problem

Existing electric scissors waste energy and require excessive time to cut thin stems and branches due to wide blade opening and long stroke requirements, leading to operator fatigue during continuous cutting.

Innovation Solution

The electric scissors incorporate a stopper mechanism that restricts the control lever's movement to an intermediate opening position, allowing for a shorter stroke and reduced energy consumption when cutting thin stems, with adjustable lockers to select optimal blade opening widths based on stem thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the movable blade is opened wide to cut thick stems and branches, then the cutting capability for thick stems is improved, but the energy consumption and time required to return the blade to the open state increases when cutting thin stems

Engineering Contradiction:
Improvecutting capability for different stem thicknessesVSAvoidenergy consumption for returning blade to open state
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the blade opening angle adjustable rather than fixed. The control lever can be positioned at multiple angles (fully open, partially open, or locked at closing position), allowing the system to adapt its blade opening width dynamically based on the stem thickness being cut. This resolves the contradiction by enabling wide opening for thick stems while allowing narrow opening for thin stems, reducing unnecessary energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of blade opening angle from a fixed state to a variable state with multiple selectable positions. By introducing adjustable opening angles (fully open, partially open) and a locked closing position, the system can optimize the blade opening parameter according to the specific cutting task, thereby reducing energy loss when cutting thin stems while maintaining the capability to cut thick stems.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the control lever has a long stroke to achieve sufficient blade opening for thick stems, then the cutting capability is improved, but the operator fatigue increases during continuous cutting of thin stems

Engineering Contradiction:
Improvecutting capability for thick stemsVSAvoidoperator fatigue during continuous cutting
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The control lever is designed with dynamic positioning capability, allowing it to be held at multiple angles (fully open, partially open, or locked at closing). This enables the operator to use a shorter lever stroke when cutting thin stems by positioning the lever at a partial opening angle, thereby reducing operator fatigue while maintaining the ability to achieve full opening when cutting thick stems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control lever's movement range is segmented into multiple discrete positions (fully open, partially open intermediate positions, and locked closing position). This segmentation allows the operator to select the appropriate stroke length based on the cutting task, using shorter strokes for thin stems and full strokes only when necessary for thick stems, thus reducing cumulative fatigue during continuous operation.

Inventive Principle:
Principle #1Segmentation

3Productivity

If the blade returns to the fully open state after cutting thin stems, then the blade is ready for next cut, but the time and energy consumption increases unnecessarily

Engineering Contradiction:
Improveblade readiness for next cutVSAvoidtime for blade to return to open state
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The blade opening state is made dynamic and adjustable rather than returning to a fixed fully open position. After cutting thin stems, the blade can remain at a partially open state or be locked at the closing position, which is sufficient for the next cutting operation. This dynamic positioning eliminates the unnecessary time and energy required to return the blade to the fully open state, thereby improving productivity while reducing time loss.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies partial action by allowing the blade to remain at a partially open state or locked closing position after cutting, rather than requiring full opening. This partial positioning is sufficient for preparing the blade for the next cut, eliminating the excessive action of returning to the fully open state and thereby reducing the time loss without compromising cutting readiness.

Inventive Principle:
Principle #16Partial or excessive action

4Adaptability or versatility

If the control lever allows full movement range for thick stem cutting, then the blade can open sufficiently wide, but the device complexity increases with additional locking mechanisms

Engineering Contradiction:
Improveblade opening widthVSAvoidlocking mechanism structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and isolates the locking function into a separate, simple locking mechanism that can be easily engaged and disengaged. This locking mechanism is integrated into the control lever assembly but operates independently, allowing the control lever to provide full movement range for thick stem cutting while the simple locking mechanism adds minimal complexity to enable the locked closing position and intermediate positioning capabilities.

Inventive Principle:
Principle #2Taking out (Extraction)

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 reduces energy waste and operator fatigue by allowing for efficient cutting of thin stems with a shorter stroke and narrower blade opening, improving the overall cutting efficiency and operability.

Implementation Method 1

The magnetic sensor detects movement of the control lever from the opening position to the closing position. The sensing medium is a magnet that allows the magnetic sensor to detect the movement of the control lever

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP3103598B1Electrical scissors
Publication Date: 2019.08.28 MAKITA CORP
  • EP3103598B1 patent drawingFigure 1
  • EP3103598B1 patent drawingFigure 2(a)~2(c)
  • EP3103598B1 patent drawingFigure 3(a)~3(b)

AI summary

Electric scissors 10 drive an electric motor 20 to bring a driven member 33 to a first position, thereby bringing a pair of blades 40 to an open state, when manipulation force of moving a control lever 50 to a closing position is not applied to the control lever 50. The electric scissors 10 drive the electric motor 20 to bring the driven member 33 to a second position upon detection by a detector 61, thereby bringing the blades 40 to a closed state, when the manipulation force of moving the control lever 50 to the closing position is applied to the control lever 50. The control lever 50 includes a stopper 70 supported to advance to and retreat from a casing 11. The casing 11 includes a locker 11b locking the stopper 70, which has advanced to the casing 11, to restrict movement of the control lever 50 toward the opening position, when the control lever 50 is in an intermediate opening position between the opening and closing positions.