Crescent Rocker Arm Cutting Plate Overlap for Heavy Lumber

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Solution Overview

Problem

Conventional cutting devices for trees are limited in cutting thicker trunks due to the restricted receiving space, which is determined by the radius of the sickle-shaped rocker, and increasing the rocker's size enhances weight and manipulation effort.

Innovation Solution

A crescent-shaped abutment with a counter-cutting plate and a toothed abutment edge parallel to the cutting edge, allowing the tree trunk to be cut on the side of the abutment and preventing deviation, while the overlapping cutting edges prevent bending and facilitate resharpening without impairing the cut.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the rocker and abutment are made larger to cut thicker tree trunks, then the cutting capacity is improved, but the weight and manipulation effort increase

Engineering Contradiction:
Improvecutting capacityVSAvoidweight
Core Design Contradiction:
Length of moving objectVSWeight of moving object

Solution Approach 1:

The invention introduces a counter-cutting plate that extends in the direction perpendicular to the cutting plate, creating a third dimension for cutting. This allows the tree trunk to be cut from both sides simultaneously, effectively increasing the cutting capacity without requiring the rocker to be larger in its primary dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cutting action is divided into two separate cutting edges: the cutting plate on the rocker and the counter-cutting plate on the abutment. Each cutting plate handles one side of the trunk, allowing the system to process thicker trunks without increasing the overall size of the rocker mechanism.

Inventive Principle:
Principle #1Segmentation

2Volume of stationary object

If the rocker size is increased to accommodate thicker trunks, then the receiving space is improved, but the device complexity increases

Engineering Contradiction:
Improvereceiving spaceVSAvoiddevice complexity
Core Design Contradiction:
Volume of stationary objectVSDevice complexity

Solution Approach 1:

The counter-cutting plate extends beyond the cutting plate in the direction perpendicular to the cutting edge, utilizing unused space in the receiving area. This effectively increases the receiving space capacity without requiring the rocker to be larger, thereby avoiding increased device complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If the cutting plate and counter-cutting plate are designed to collide for clean cuts, then the cutting quality is improved, but the reliability decreases due to bending under heavy loads

Engineering Contradiction:
Improvecutting qualityVSAvoidreliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The cutting plates are designed to overlap rather than just touch or collide. This excessive action ensures that even if the plates bend under heavy loads, the overlapping area maintains sufficient contact to complete the cut. The overlap provides a margin of error that compensates for deformation under load.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The overlapping design of the cutting plates anticipates potential bending under heavy loads by providing extra contact area before the bending occurs. This pre-built tolerance ensures that the cutting edges remain effective even when subjected to unexpected stress during operation.

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

Data Source

PatentEP3085224B1Device for cutting heavy lumber
Publication Date: 2018.03.07 STEININGER WERNER
  • EP3085224B1 patent drawingFigure 1~2
  • EP3085224B1 patent drawingFigure 3~4
  • EP3085224B1 patent drawingFigure 5~6

AI summary

A device for cutting heavy material, in particular trees, comprising a base part (2) and a rocker arm (1) pivotably arranged relative to the base part (2) from an open position to a closed position, the rocker arm being crescent-shaped and carrying a cutting plate (5), wherein the rocker arm (1) is spaced apart from a support (7) of the base part (2) in its open position, and in its closed position, together with the support (7) of the base part (2), defines a receiving space (11) for cut material, which is traversed by the cutting plate (5), wherein the support (7) projects crescent-shaped from the base part (2) and has a counter-cutting plate (6) traversing the receiving space (11). According to the invention, the counter-cutting plate (6) of the support (7) and the cutting plate (5) of the rocker arm (1) overlap in their closed position.By means of the measures provided according to the invention, the receiving space (11) of the cutting unit is enlarged, so that now larger tree trunks can also be cut without having to enlarge the swing arm (1).