Cutting Machine Overlapping Knives Pivot Mechanism
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Solution Overview
Problem
Existing cutting machines, such as hedge trimmers, face issues with cutting large diameter branches due to significant cutting forces and lack of sharpness, and the design of overlapping knives can lead to damage and interference, resulting in discontinuous cutting and potential damage to the cutting mechanism.
Innovation Solution
The cutting machine design features overlapping knives during rotation, with at least one knife being pivotally mounted, allowing for simultaneous cutting and retraction when encountering obstacles, reducing cutting force and increasing sharpness through a knife-counter-knife effect, and standardizing the construction with identical drive means and plates for all cutting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If knives are arranged to overlap behind the front edge of the housing, then the cutting machine can cut grass effectively, but the rigidity of branches prevents them from reaching the cutting elements, resulting in discontinuous cutting
Solution Approach 1:
The patent inverts the conventional knife arrangement by positioning the overlapping zone in front of the housing front edge rather than behind it. This reversal allows rigid branches to be engaged by the cutting elements before they reach the housing, ensuring continuous cutting action on all vegetation types including woody branches.
2Device complexity
If knives are fixed on the cutting elements, then the structure is simple, but the knives can easily be damaged when encountering obstacles and cannot retract, causing serious damage to the cutting means and drive means
Solution Approach 1:
The patent transforms the static fixed knife arrangement into a dynamic system where knives can pivot relative to their mounting plates. This dynamic capability allows knives to retract automatically when encountering obstacles or hard objects, protecting both the knives themselves and the expensive drive mechanism from damage.
Solution Approach 2:
The patent implements a protective mechanism by allowing knives to pivot and retract before significant damage can occur. The pivoting capability acts as a cushioning mechanism that absorbs impact energy from obstacles, preventing the transmission of damaging forces to the drive means and other critical components.
3Device complexity
If a single knife cuts branches, then the structure is simple, but significant cutting forces are required especially for large diameter branches, and the cut lacks sharpness
Solution Approach 1:
The patent merges the cutting action of multiple knives by arranging them to overlap in front of the housing. This combining of cutting elements creates a multi-knife cutting system where several knives simultaneously engage the same branch, distributing the cutting force and producing a sharper, cleaner cut compared to a single knife.
4Stability of the object's composition
If cutting elements are arranged to cut in the same plane without knife collision, then the structure is stable, but the cutting paths do not overlap, resulting in discontinuous cutting on branches
Solution Approach 1:
The patent inverts the conventional stable arrangement by allowing cutting elements to operate in slightly different planes that converge in front of the housing. This inverted approach creates overlapping cutting paths that ensure continuous cutting action on branches, while the pivoting knife mechanism prevents collisions that would compromise stability.
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 facilitates efficient cutting of large diameter branches with reduced cutting force and enhanced sharpness, while minimizing knife damage and preventing costly transmission damage by allowing knives to retract and absorb impact energy.
Implementation Method 1
at least one knife being a pivoting knife pivotally mounted around an axis secured to the corresponding plate and allowing said pivoting knife to retract by pivoting around said axis
Implementation Method 2
the cutting of which is facilitated by the shearing action generated by each knife on either side of the branch
Data Source
Figure 1
Figure 2~3
AI summary
The machine has a casing (6) for carrying cutting elements (7a-7d) that are driven in rotation by a transmission (10). The cutting elements comprise knives (9) e.g. upper knives (9s) and lower knives (9i). The knives of one of the cutting elements overlap with the knives of the other adjacent cutting element in front of the casing during synchronized rotation of the cutting elements. The cutting elements comprise plates (13) that carry the knives and driven in rotation in a same plane. The cutting elements are aligned according to a length of the casing.