Segmented Plunger Rod and Backstop Device for Syringe
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Solution Overview
Problem
Current syringe plunger rod designs are inefficient in terms of material usage and manufacturing time, leading to high costs and prolonged cycle times due to excessive material in the central region, which also results in susceptibility to breakage.
Innovation Solution
A plunger rod with a discontinuous arcuate outer perimeter and a backstop device featuring a top plate with a smaller volume than the bottom plate, allowing for reduced material usage and faster manufacturing, while maintaining the distal end of the plunger rod within the syringe barrel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a plunger rod with excessive material in the central region is used, then the plunger rod has sufficient strength and structural integrity, but the material usage increases and manufacturing time is prolonged
Solution Approach 1:
The plunger rod is segmented into multiple portions (first portion, second portion, third portion) with different material distributions. The central region is divided into a first central region and a second central region, allowing selective material placement. This segmentation enables the rod to achieve necessary strength at critical locations while reducing overall material usage and manufacturing time.
Solution Approach 2:
Different regions of the plunger rod are assigned different material qualities and distributions. The first and second portions have different material characteristics, and the central regions have different material densities. This local quality approach ensures sufficient strength where needed while minimizing material usage in less critical areas, thereby reducing manufacturing time and cost.
2Stability of the object's composition
If a plunger rod with excessive material in the central region is used, then the plunger rod has sufficient structural integrity, but the manufacturing cycle time increases
Solution Approach 1:
By segmenting the plunger rod into multiple portions with different material requirements, the manufacturing process can be optimized for each segment. The segmented structure allows for more efficient molding cycles as each portion can be formed with appropriate material distribution, reducing overall manufacturing time while maintaining structural integrity.
Solution Approach 2:
The local quality differentiation allows the manufacturing process to focus material resources where structurally necessary, reducing the overall manufacturing cycle time. The first and second portions can be manufactured with different material densities, enabling faster production of the overall component while maintaining necessary structural integrity at critical locations.
3Reliability
If a plunger rod with excessive material in the central region is used, then the plunger rod is less susceptible to breakage, but the manufacturing cost increases
Solution Approach 1:
Segmenting the plunger rod allows for targeted material placement in regions most susceptible to breakage. The first, second, and third portions can be manufactured with different material distributions, placing strength where breakage is most likely to occur while avoiding unnecessary material costs in other regions.
Solution Approach 2:
By applying different material qualities to different portions and central regions, the design achieves breakage resistance at critical locations without the need for excessive material throughout the entire rod. This localized approach to quality enhancement reduces manufacturing cost while maintaining reliability.
4Stability of the object's composition
If a backstop device with larger volume is used, then the backstop provides sufficient support and stability, but the material usage and manufacturing time increase
Solution Approach 1:
The backstop device is segmented into a first portion and a second portion, each with different material distributions. This segmentation allows the design to achieve necessary stability in critical regions while reducing material usage and manufacturing time in other regions, optimizing the balance between stability and production efficiency.
Solution Approach 2:
Different portions of the backstop device are assigned different material qualities. The first and second portions have different material densities and characteristics, allowing the device to provide sufficient stability where needed while minimizing material usage and manufacturing time in less critical areas.
Data Source
Figure 1~2B
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AI summary
A backstop device for maintaining a distal end of a plunger rod in a syringe barrel comprises a top plate defining a first opening configured to receive a plunger rod having an elongated body having a joining portion joining a first curved end face to a second curved end face therein. The backstop device also comprises a bottom plate defining a second opening configured to receive a syringe barrel therein and at least one connector extending between the top and bottom plates. The first opening has a shape different from a shape of the second opening. An injection device usable with the backstop device comprises a plunger rod having an elongated body with a joining portion joining first and second curved end faces that together define a discontinuous arcuate outer perimeter of the elongated body.