Reciprocating Cutter Jam Management via Switch Sequence

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Solution Overview

Problem

Hedge trimmers experience frequent direction changes and reduced efficiency due to automatic reversal of cutter movement when dealing with dense branches, leading to operator inconvenience and increased risk of injury.

Innovation Solution

A reciprocating cutting apparatus with a control unit that stops and restarts the cutting unit's drive action based on a predetermined sequence of switch operations, allowing the operator to choose between forward and reverse operations without releasing their hands, thereby improving efficiency and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the cutter movement direction is automatically reversed when a jam is detected, then the jammed branch can be released, but the hedge trimmer operation is stopped multiple times when branches are too dense, reducing operating efficiency

Engineering Contradiction:
Improvejam release capabilityVSAvoidoperating efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the anti-jam response based on the jam frequency. When jam frequency exceeds a threshold, the system switches from automatic reversal to requiring manual switch operation, allowing continuous operation through dense branches while still providing jam release capability when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control apparatus changes the operational parameters by adjusting the response to jams based on the frequency of occurrence. The system monitors jam frequency and changes the operational mode parameter accordingly, transitioning between automatic reversal mode and manual control mode to optimize both safety and efficiency.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the cutter movement direction is automatically reversed when a jam occurs, then the trimmer can clear the jam, but the operator cannot perform other operations and cannot adjust the reciprocation of the cutters, increasing labor and danger

Engineering Contradiction:
Improveautomatic jam clearanceVSAvoidoperator control flexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system provides dynamic control flexibility by allowing operators to choose between automatic reversal and manual switch operation based on the situation. When jam frequency is low, automatic reversal provides hands-free operation. When jam frequency is high, manual switch operation allows operators to maintain control and perform other tasks.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system offers self-service through automatic reversal when jams occur at low frequency, freeing the operator's hands. However, it transitions to requiring manual service when jam frequency increases, ensuring operator control while still providing the option for automatic intervention when appropriate.

Inventive Principle:
Principle #25Self-service

3Reliability

If the movement direction of cutters is controlled automatically when jam or loss in speed is detected, then the trimmer can respond to jams, but the operator must release switches to cut off motive power, holding the trimmer at the jam position and requiring manual clearing

Engineering Contradiction:
Improvejam detection responseVSAvoidcontinuous operation capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system dynamically determines whether to enable automatic reversal or require manual switch operation based on jam frequency. This dynamic adjustment allows the system to provide appropriate response level for each operating condition, maintaining continuous operation capability while responding to jams when necessary.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control apparatus uses feedback from jam frequency monitoring to adjust the operational mode. The system continuously monitors jams and uses this feedback to determine whether to switch between automatic reversal mode and manual control mode, optimizing both safety and operational continuity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3984348A1Cutting apparatus
Publication Date: 2022.04.20 TECHTRONIC CORDLESS GP
  • EP3984348A1 patent drawingFigure 1~2
  • EP3984348A1 patent drawingFigure 3~4
  • EP3984348A1 patent drawingFigure 5

AI summary

A reciprocating cutting apparatus comprises a cutting unit (100), a drive unit (300), a control unit and a switch apparatus. The cutting unit comprises at least one cutter (110, 120) which reciprocates between two set points of maximum travel under the driving action of the drive unit (300), in order to perform a cutting operation, and the control unit is configured to stop the normal supply of power to the drive unit (300) when an abnormal event is detected, wherein the control unit is further configured to restore the normal supply of power to the drive unit (300) when a predetermined sequence of operations on the switch apparatus is detected, and control the drive unit (300) such that the cutting unit performs a reverse operation.