Deformable Knife Carrier Assembly for Fast Lawn Mower Blade Exchange
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Solution Overview
Problem
Existing knife units in cutter assemblies are cumbersome to dismount and exchange, posing a risk of injury and increasing maintenance costs, as they are often fixedly attached to rotating structures with complex components.
Innovation Solution
A knife unit with a support structure featuring deformable portions, such as radial slits and weakened areas, allowing for easy mounting and demounting by temporary deformation, which securely fastens to a rotatable structure, reducing the risk of injury and simplifying maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If knives are fixedly attached to the rotating drive shaft with multiple small components, then the attachment is secure, but the dismounting becomes cumbersome and time-consuming
Solution Approach 1:
The knife carrier arrangement is separated into a stationary part (attached to drive shaft) and a detachable knife unit. This segmentation allows the knife unit to be quickly removed and replaced without dismantling multiple fastening components, resolving the contradiction between secure attachment and quick maintenance.
Solution Approach 2:
The knives are merged with the support structure to form an integrated knife unit. This combining eliminates the need to handle multiple separate components during maintenance, allowing the entire knife assembly to be exchanged as one unit, thus reducing maintenance time while maintaining secure attachment during operation.
2Reliability
If knives are fixedly attached with multiple small components, then the attachment is secure, but the risk of injury during handling increases
Solution Approach 1:
By segmenting the knife carrier into a stationary part and a detachable knife unit, the design reduces the number of small fastening components that need to be manually handled. This segmentation minimizes exposure to sharp edges and moving parts during maintenance, thereby reducing injury risk while maintaining secure attachment during operation.
Solution Approach 2:
The knife unit is designed to be self-contained and easily exchangeable as a single unit. This self-service design allows users to replace knives without complex assembly/disassembly operations, reducing the time spent handling potentially dangerous components and minimizing injury risk.
3Reliability
If the support structure is made rigid to ensure secure positioning, then the fastening is reliable, but the mounting and demounting becomes difficult
Solution Approach 1:
The support structure incorporates deformable portions that allow temporary deformation during mounting/demounting operations. These deformable sections enable the knife unit to be easily installed and removed, while the overall structure maintains sufficient rigidity to ensure secure positioning during normal operation, thus resolving the contradiction between reliability and ease of operation.
4Loss of time
If the knife unit design is simplified for easy exchange, then the maintenance is quicker, but the secure fastening during extended use may be compromised
Solution Approach 1:
The segmentation into stationary and detachable parts allows for quick exchange of the knife unit while maintaining a secure connection interface. The simplified design focuses on the detachable knife unit rather than complicating the entire assembly, enabling fast maintenance without compromising fastening security through proper interface design.
Solution Approach 2:
The support structure has different local properties: deformable portions for easy mounting/demounting and rigid portions for secure positioning during operation. This local quality differentiation allows the knife unit to be quickly exchanged while ensuring reliable fastening during extended use, resolving the contradiction between exchange speed and fastening security.
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
Enables quick and safe exchange of knives with reduced risk of injury and lower maintenance costs, as the knife unit can be easily snapped into and out of place, maintaining secure positioning during use.
Implementation Method 1
the support structure is arranged to be deformable in one or more discrete portions thereof
Implementation Method 2
the knife unit may be temporarily deformed, so that it may be mounted on the knife carrier arrangement, while regaining its shape in a mounted position
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2a~2b
AI summary
A knife unit (7a, 7b) for a cutter assembly in a work tool comprises one or more knives (13a, 13b) and a support structure (14a, 14b). The support structure (14a, 14b) comprises a connector (20a, 20b) arranged at least partly at a peripheral edge of the support structure (1a, 1b) for connection with a rotatable structure (1a, 1b). A knife carrier arrangement includes the detachable knife unit (7a, 7b). A lawn mower comprises the knife carrier arrangement (1a, 1b). A method for performing a knife exchange in a work tool comprises the steps of: deforming the knife unit (7a, 7b), loosening a connection portion (20a, 20b) of the support structure (14a, 14b) from the knife carrier arrangement (1a, 1b), dismounting the knife unit (7a, 7b), placing a second knife unit (7a, 7b) on the knife carrier arrangement (1a, 1b), and deforming the second knife unit (7a, 7b) to bring it into connection with the knife carrier arrangement (1a, 1b).