Segmented Universal Joint Spider for Smoother Pedal Operation
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Solution Overview
Problem
Existing universal joints used in musical instrument pedal devices, such as those for bass drums, generate a large rotational moment force due to their bulky spider components, leading to uneven pedal operation and an awkward playing experience.
Innovation Solution
A universal joint design featuring two yokes connected to rotary members, a spider rotationally coupled to the yokes, and a bearing that rotationally supports the spider, allowing the spider to be arranged within the space defined by the yokes and enabling the outer ring of the bearing to be fixed to the spider, thereby reducing the rotational moment force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a traditional spider component is used in the universal joint, then the structural strength is sufficient, but the rotational moment force becomes large causing uneven pedal operation
Solution Approach 1:
The spider component is divided into two separate segments that are coupled together. This segmentation allows each segment to be optimized independently, reducing the overall rotational moment force while maintaining structural strength. The split spider design reduces the distance from the rotation axis to the bearing contact points, thereby reducing the moment arm and the resulting rotational moment force.
2Manufacturing precision
If the spider is made as a single component, then the manufacturing process is simpler, but the positional accuracy and dimensional accuracy are strictly required making manufacturing difficult
Solution Approach 1:
Dividing the spider into two segments reduces the manufacturing precision requirements for each individual segment. Each segment has fewer bearing-fixing holes (typically two per segment), which reduces the cumulative error and makes positioning and drilling easier. The segmentation allows for more tolerant manufacturing specifications while maintaining the overall functional accuracy of the universal joint.
3Ease of manufacture
If the spider is made as a single component, then the number of components is reduced, but the positional accuracy and dimensional accuracy are strictly required
Solution Approach 1:
While segmentation increases the component count from one to two, it significantly improves ease of manufacture by reducing the precision requirements. Each segment can be manufactured separately with less stringent tolerances, and the coupling interface between segments is designed to accommodate minor variations. This approach trades a small increase in assembly complexity for a significant reduction in manufacturing difficulty and cost.
4Reliability
If the outer ring of the bearing is fixed in the holes of the spider, then the bearing is securely mounted, but the holes must be precisely positioned and sized
Solution Approach 1:
Segmenting the spider reduces the number of bearing-mounting holes from four to two per segment, which reduces the statistical probability of dimensional deviations. With fewer holes to position and drill, the cumulative error is reduced, and each individual hole can be manufactured with more relaxed tolerances while still achieving secure bearing mounting.
5Strength
If a bulky spider is used, then the structural strength is sufficient, but the rotational moment force becomes large
Solution Approach 1:
The segmented spider design allows for optimized load paths in each segment. By splitting the structure, each segment can be designed to efficiently handle the specific forces acting on it, reducing the overall material required while maintaining strength. The segmentation creates shorter moment arms from the rotation axis to the bearing contact points, which directly reduces the rotational moment force even though the structural integrity is preserved through proper segment coupling.
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
The new universal joint design reduces the rotational moment force, resulting in a more consistent and comfortable playing experience when using the left and right pedal devices, and also simplifies the manufacturing process by reducing the complexity and size of the spider component.
Implementation Method 1
a bearing disposed at a portion that couples the two yokes to the spider, the bearing rotationally supporting the spider
Data Source
AI summary
A universal joint includes two yokes respectively connected to two rotary members, a spider rotationally coupled to the two yokes, and a bearing disposed at a portion that couples the two yokes to the spider, the bearing rotationally supporting the spider. The spider is configured to be arranged in a space defined by inner surfaces of the two yokes and allow an outer ring of the bearing to be fixed to the spider.