Two-Speed Trailer Jack with Variable Thread Pitch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional linear trailer jacks require numerous rotations to lift heavy loads due to constant thread pitches, leading to time-consuming operations.
Innovation Solution
A two-speed linear jack system with a high-speed assembly and a low-speed assembly, where the high-speed assembly disengages upon ground contact, allowing the low-speed assembly to provide mechanical advantage for lifting heavy loads efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a constant thread pitch is used in conventional linear trailer jacks, then the jack can lift heavy loads with mechanical advantage, but numerous rotations are required leading to time-consuming operations
Solution Approach 1:
The patent applies dynamics by making the thread pitch variable rather than constant. The jack screw features different thread pitches in different sections: a first thread pitch for initial extension and a second thread pitch for lifting. This dynamic change in thread pitch allows the system to optimize between speed and mechanical advantage during different phases of operation.
Solution Approach 2:
The jack screw is segmented into multiple sections with different thread pitches. The first section has a first thread pitch optimized for rapid extension, while the second section has a second thread pitch optimized for lifting heavy loads. This segmentation allows each section to perform its specialized function, reducing total operation time while maintaining lifting capability.
2Force
If numerous rotations are performed to lift heavy loads, then mechanical advantage is achieved, but the operation becomes time-consuming and labor-intensive
Solution Approach 1:
The variable thread pitch design dynamically adjusts the mechanical characteristics during operation. The first thread pitch provides faster rotation-to-linear-motion conversion for ease of operation during extension, while the second thread pitch provides higher mechanical advantage during the lifting phase, reducing the total number of rotations required.
Solution Approach 2:
The patent changes the thread pitch parameter along the length of the jack screw. By varying this critical parameter, the system optimizes both ease of operation and mechanical advantage without requiring excessive rotations, making the overall operation less labor-intensive.
3Speed
If a single thread pitch is used throughout the jack screw, then the structure is simple, but the jack cannot quickly extend upon ground contact
Solution Approach 1:
The jack screw is divided into segmented sections with different thread pitches. The first section is optimized for rapid extension when the jack contacts the ground, while the second section is optimized for lifting. This segmentation enables quick extension without significantly increasing overall structural complexity.
Solution Approach 2:
Different sections of the jack screw have different local qualities in terms of thread pitch. The first section has a coarser pitch for rapid extension, while the second section has a finer pitch for lifting. This local differentiation optimizes performance for each phase of operation while maintaining a relatively simple overall structure.
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 two-speed system reduces the number of rotations needed to lift loads by quickly extending the jack's length upon ground contact, enhancing ease of use and reducing operation time while maintaining mechanical advantage.
Implementation Method 1
The outer sleeve is threadedly coupled to an outer diameter surface of the inner sleeve. The inner screw is threadedly coupled to an inner diameter surface of the inner sleeve.
Implementation Method 2
a spring operatively coupled to the outer sleeve. The outer sleeve is slidable in the outer tube between a first position and a second position. In the first position, the spring biases the outer sleeve to engage the shaft gear
Data Source
AI summary
A linear jack includes an outer sleeve, an inner sleeve disposed at least partially within the outer sleeve, and an inner screw disposed at least partially within the inner sleeve. The outer sleeve is threadedly coupled to an outer diameter surface of the inner sleeve. The inner screw is threadedly coupled to an inner diameter surface of the inner sleeve. A thread pitch of the outer sleeve is greater than a thread pitch of the inner screw.