Electric Scissors With Adjustable Lever Length
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Solution Overview
Problem
Conventional scissors face challenges in applying sufficient cutting force for thick objects and achieving high cutting speed for thin objects due to limited opening angles and lever lengths, restricting the size and type of materials that can be cut.
Innovation Solution
The scissors feature an articulation device with multiple pivot points and a slot-shaped opening that allows the lever length to adjust based on the opening angle, enabling increased cutting force and speed by switching between different lever lengths, allowing for larger opening angles and accommodating thicker materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the lever length is increased to apply greater cutting force on thick objects, then the cutting force is improved, but the cutting speed decreases
Solution Approach 1:
The patent applies the dynamics principle by making the lever length adjustable rather than fixed. The articulation device can switch between different articulation points on the movable blade, allowing the lever length to dynamically change based on the cutting task. When cutting thick objects, the system switches to a longer lever length to maximize cutting force. When cutting thin objects, it switches to a shorter lever length to maximize cutting speed, thus resolving the contradiction between force and speed.
2Speed
If the opening angle is limited to achieve high cutting speed, then the cutting speed is improved, but the ability to cut thicker objects is reduced
Solution Approach 1:
The patent resolves this contradiction by making the opening angle adjustable through the articulation device. The system can dynamically change the maximum opening angle by switching between different articulation points. For thin objects, it uses a smaller opening angle to maintain high cutting speed. For thick objects, it switches to a larger opening angle to accommodate the material thickness while maintaining cutting capability, thus achieving both high speed and adaptability.
3Device complexity
If a fixed lever length is used, then the device complexity is reduced, but the adaptability to different cutting tasks is limited
Solution Approach 1:
The patent applies segmentation by dividing the articulation device into multiple discrete articulation points on the movable blade. Instead of a continuous adjustment mechanism, the system uses distinct, separable articulation points that can be switched between. This segmented approach provides adaptability to different cutting tasks (thick vs. thin objects) while keeping the device relatively simple, as it only requires additional articulation points rather than complex continuous adjustment mechanisms.
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 enables higher cutting forces with the same motor power, allowing for efficient cutting of thicker materials with increased speed and versatility in cutting various object sizes.
Implementation Method 1
the articulation device consists of a link and the outer contour of the fixed blade is designed in such a way or the kinematic relationship between the link and the slot-shaped opening is selected in such a way that from a defined opening angle of the two Knife the handlebar runs up against the outer contour of the fixed knife with a run-on area and, as the opening angle increases, the handlebar is gradually moved from a first end stop area, which corresponds to a shorter lever length, to a second end stop area, which corresponds to a longer lever arm
Implementation Method 2
a spindle lifting gear for driving a movable knife, which consists of a ball screw and a ball screw nut, the ball screw being connected to the output shaft of an electric geared motor
Implementation Method 3
an electric geared motor
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
The scissor (1), particularly electrical scissor, comprises a fixed blade (101), a moving blade (102) and an electrical drive (104) which actuates a linking device (105). The moving blade has two linking points (201,202) for a link connection with the linking device which is switched between both the linking points. The linking device is connected with the moving blade.