Integral Jack Nut Grease Fitting for Direct Lubrication
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Solution Overview
Problem
Existing jack designs require partial disassembly or inconvenient grease fitting locations, leading to premature failure due to grease wear and breakdown, causing increased friction and motor overheating.
Innovation Solution
Positioning grease fittings within the jack nut or screw load bearing elements for direct lubrication access, allowing lubricants to be applied at the contact region between the screw and nut, thereby extending the jack's life cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grease fittings are provided at fixed external access points on the threaded positioning device, then the device structure is simple, but the lubrication effectiveness is insufficient leading to premature failure
Solution Approach 1:
The grease fitting is nested within the drive nut itself, with the fitting body formed as an integral part of the nut structure. The fitting is positioned inside the nut and accessible through a port in the outer tube, allowing grease to be delivered directly to the thread engagement region between the jackscrew and drive nut, thereby improving lubrication effectiveness without adding external complexity
Solution Approach 2:
A port in the outer tube serves as an intermediary access point that aligns with the grease fitting port in the drive nut during operation. This intermediary structure allows grease to be introduced through the outer tube port and delivered directly to the internal thread contact region, solving the problem of inaccessible grease fittings while maintaining structural simplicity
2Reliability
If grease is applied to external surfaces of the jack, then the application process is simple, but the grease does not reach the critical contact regions between screw and nut
Solution Approach 1:
The grease fitting function is extracted from external surfaces and repositioned to the critical internal contact region between the jackscrew threads and drive nut threads. By placing the grease fitting port within the drive nut and providing access through the outer tube port, grease is delivered directly to where it is most needed, ensuring effective lubrication of the thread engagement interface
Solution Approach 2:
The grease fitting is pre-positioned within the drive nut structure during manufacturing, with the fitting port aligned to receive grease delivery. This preliminary placement ensures that when grease is applied through the outer tube port, it is immediately directed to the critical thread contact region, eliminating the need for disassembly or complex application procedures
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
This solution increases the life cycle of jacks by over 100% by maintaining effective lubrication between the jackscrew and nut, reducing friction and motor strain.
Implementation Method 1
Positioning grease fittings within the jack nut or screw load bearing elements for direct lubrication access, allowing lubricants to be applied at the contact region between the screw and nut
Data Source
AI summary
An improved device and method of lubrication for a tongue jack, 5th wheel jack, or other jack or other threaded positioning device. Ports are provided in the inner and outer tubes of the jack. The aligned ports provide access to a lubrication cavity in the jacknut. The lubrication cavity may include a grease fitting such as a zerk fitting. When the ports are in alignment, a grease gun can be inserted easily to the zerk fitting to apply grease to the interior structure of the nut as well as to the threads of the jackscrew. The lubricant may be introduced directly at a region of contact between a screw and the load bearing element. Applicant's test results show that this improved lubrication can increase the life cycle of the jack by more than 100%.