Rack Exchange Jig for Calibrated Multi-Pinion Gearboxes
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Solution Overview
Problem
Rack and pinion drive arrangements with multiple pinions face challenges in maintaining accurate calibration and handling due to the cumbersome assembly, calibration, and transportation of long and heavy racks, which are prone to damage.
Innovation Solution
A method involving a jig assembly with an auxiliary rack and coupling mechanism allows for the calibration and separation of the utility rack from the gearbox, enabling easy handling and transportation, while maintaining calibration through an auxiliary rack that maintains the nominal rotational position and pre-tensioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the rack is made long and heavy to achieve the required force transmission, then the torque transmission capability is improved, but the ease of handling and transportation deteriorates
Solution Approach 1:
The rack is divided into a first rack portion that remains installed in the gearbox and a second rack portion that can be detached and exchanged. This segmentation allows the heavy, long rack to be handled in smaller, more manageable sections while maintaining the overall force transmission capability when assembled.
Solution Approach 2:
The second rack portion is extracted from the complete rack assembly, allowing it to be removed and exchanged independently. This extraction enables the rack to be transported in parts rather than as a single heavy unit, significantly improving ease of handling and transportation while preserving the full torque transmission capability when reassembled.
2Strength
If the rack is made strong and durable to withstand high loads, then the strength and durability are improved, but the weight increases making handling cumbersome
Solution Approach 1:
The strong, durable rack is segmented into multiple portions, with only the critical first rack portion permanently installed in the gearbox. The second rack portion can be exchanged and does not need to be as heavy-duty, reducing overall weight while maintaining strength where most needed.
Solution Approach 2:
The second rack portion is extracted as a separate, exchangeable component. This allows the primary strength and durability requirements to be concentrated in the first rack portion that remains installed, while the extracted second portion can be lighter and easier to handle, reducing overall weight without compromising essential strength.
3Measurement precision
If the rack is kept installed in meshing contact with pinions to maintain calibration, then the calibration accuracy is preserved, but the ease of transportation deteriorates
Solution Approach 1:
The rack is segmented such that the first rack portion remains installed to maintain calibration, while the second rack portion can be removed for transportation. This segmentation allows calibration maintenance without requiring the entire rack to remain installed, improving ease of transportation.
Solution Approach 2:
The second rack portion is extracted and removed from the assembly during transportation. Since the first rack portion remains installed and in meshing contact with the pinions, calibration accuracy is preserved while the extracted second portion enables easier transportation of the overall system.
4Ease of repair
If the rack is made exchangeable to facilitate maintenance and installation, then the ease of repair is improved, but the device complexity increases
Solution Approach 1:
The rack is segmented into a first fixed portion and a second exchangeable portion connected by a coupling mechanism. This segmentation enables the second portion to be removed and replaced during maintenance without affecting the first portion, significantly improving ease of repair while adding only moderate complexity through the coupling mechanism.
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
Facilitates efficient assembly, calibration, and safe transportation of rack and pinion drive arrangements by allowing the utility rack to be separated from the gearbox, reducing the risk of damage and ensuring precise calibration is maintained during handling and installation.
Implementation Method 1
each pinion is fixed to the respective primary gear by means of a respective elastically deformable fixation device which allows a limited relative rotation between the respective pinion and primary gear
Data Source
AI summary
A method of exchanging a rack of a rack and pinion drive arrangement, and associated jig assembly, are disclosed. The method includes providing a rack and pinion drive arrangement, with a first rack installed in meshing engagement with the pinions of the gearbox; providing a jig assembly comprising a second toothed rack and a coupling arrangement; arranging the second rack in longitudinal coaxial alignment with the first rack; connecting a first end of the second rack to a proximal end of the first rack, via the coupling arrangement; bringing the second rack into meshing engagement with the pinions of the gearbox by linear displacement of the first and second rack, disconnecting the first rack from the second rack. The nominal rotational position between the respective pinions and primary gears may be calibrated either when the first or the second rack is in meshing engagement with the pinions of the gearbox.