Variable Length Connecting Rod for Turbomachines
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Solution Overview
Problem
Current connecting rods for aircraft turbine engines, such as helicopters, have a limited adjustable range, particularly failing to shorten to a desired minimum length, and are not mass-efficient, with a narrow adjustment range and high mass.
Innovation Solution
A connecting rod design featuring two opposite longitudinal ends connected to threaded pins within a coaxial adjusting sleeve, allowing for sliding and adjustable length through a housing, with lock nuts for immobilization, enabling a wider adjustment range and significant mass reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a threaded pin design is used for adjusting connecting rod length, then the connecting rod can be lengthened to a maximum value, but it cannot be shortened to a desired minimum value
Solution Approach 1:
The first threaded pin is inserted into the housing of the second threaded pin, creating a nested configuration. This allows the pins to overlap and reduce the overall length of the connecting rod when retracted, enabling the rod to be shortened to a desired minimum value while maintaining the ability to extend to a maximum value.
Solution Approach 2:
The invention transitions from a linear extension mechanism to a nested three-dimensional arrangement. By allowing the first pin to slide within the housing of the second pin, the design utilizes internal space efficiently, enabling both extension and retraction beyond the limitations of a simple linear threaded pin design.
2Device complexity
If a conventional threaded pin design is used, then the structure is simple, but the mass of the connecting rod is high
Solution Approach 1:
By nesting the first threaded pin within the housing of the second threaded pin, the design reduces the overall material required for the connecting rod. This nested configuration eliminates the need for separate, full-length pins, thereby reducing mass while maintaining structural integrity and adjustment functionality.
Solution Approach 2:
The invention introduces a sliding mechanism where the first pin can move dynamically within the housing of the second pin. This dynamic arrangement allows the connecting rod to adapt its length, enabling mass reduction through optimized material distribution while preserving the ability to achieve both minimum and maximum length requirements.
3Device complexity
If a conventional threaded pin design is used, then the structure is straightforward, but the adjustment range is narrow
Solution Approach 1:
The nested arrangement of the first threaded pin within the housing of the second threaded pin creates overlapping adjustment ranges. This configuration enables the connecting rod to be adjusted over a broader range of lengths, from a reduced minimum value when pins are nested to a maximum value when pins are extended, thereby expanding the overall adaptability.
Solution Approach 2:
By utilizing the three-dimensional nested configuration, the invention expands the adjustment range beyond what a simple linear design can achieve. The sliding mechanism within the housing allows for greater positional variability, enabling both minimum and maximum length adjustments that exceed the capabilities of conventional designs.
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 design allows for a broader adjustable range of -12mm to +12mm and a 35% mass savings, enabling precise length adjustment and improved integration in space-constrained environments.
Implementation Method 1
a first longitudinal end 24 of the connecting rod 18 comprises a threaded hole for screwing an end portion 26 of a threaded pin 28, and a second longitudinal end 30 of the connecting rod 18 comprises a threaded hole for screwing an end portion 32 opposite the threaded shaft 28
Data Source
Figure 1~3
Figure 4~5
Figure 6~8
AI summary
Adjustable-length connecting rod (40) for an aircraft turbomachine (10), this connecting rod having a generally elongate shape and comprising two longitudinal opposite ends (42, 50) for attachment to elements to be connected, characterised in that: • - a first (42) of these longitudinal ends is connected to a first threaded shaft (44) screwed into a first tubular portion (46) of an adjustment sleeve (48), • - a second (50) of these longitudinal ends is connected to a second threaded shaft (52) screwed into a second tubular portion (54) of the adjustment sleeve, and further comprising a housing (56) in which at least a portion of the first shaft is configured to slide.