Pivot Assembly Reduces Bending Stress in Manual Valve Hand Jacks
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Solution Overview
Problem
Conventional hand jacks for manually operating fluid valves generate unwanted friction and bending forces due to the arcuate path of the rod, leading to increased wear and tear on the device and a higher risk of structural failure from excessive load on mounting bolts.
Innovation Solution
The introduction of a pivot washer with a ridged surface and a thrust bearing between the handwheel and the bracket provides an additional pivot point, allowing the connecting rod to swing freely and reducing friction and bending stress, thereby alleviating the need for excessive force to operate the valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rod is held in a substantially constant attitude with respect to the valve stem while the lever pivots through an arcuate path, then the valve stem can be reliably raised or lowered, but significant bending forces are generated on the rod increasing friction and operational force requirements
Solution Approach 1:
The patent applies the dynamics principle by allowing the rod to dynamically change its attitude relative to the valve stem during operation. Instead of maintaining a constant attitude, the rod is permitted to pivot and adjust its angle as the lever moves through its arcuate path. This dynamic adjustment eliminates excessive bending forces while maintaining reliable valve stem positioning throughout the full range of motion.
2Strength
If the rod follows an arcuate path during lever pivoting, then the lever can engage the valve stem effectively, but bending forces magnify the load on mounting bolts increasing structural failure risk
Solution Approach 1:
The rod is designed to dynamically adjust its orientation during operation, pivoting at the coupling between the bracket and rod. This dynamic movement allows the rod to follow a more favorable path that maintains effective lever engagement with the valve stem while significantly reducing bending forces transmitted to the mounting bolts, thereby improving structural reliability.
3Stability of the object's composition
If the rod is constrained to maintain constant attitude, then coupling mechanisms are secured firmly, but wear and tear on the device increases due to heightened friction
Solution Approach 1:
The coupling mechanism between the bracket and rod is designed to accommodate dynamic movement. The rod can pivot at this coupling point, allowing it to adjust its attitude during operation. This dynamic capability maintains stable coupling engagement while reducing friction and wear, thereby extending the device's service life without compromising coupling stability.
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 significantly reduces the operational load required to turn the handwheel, from approximately 65 foot pounds to 20 foot pounds, minimizing stress on the coupling and extending the lifespan of the hand jack and valve assembly.
Implementation Method 1
a thrust bearing between the handwheel and the bracket provides an additional pivot point
Data Source
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AI summary
A pivot assembly (100) provides an economical means for reducing the load on a manually operated hand jack (50) by providing a pivot point on the body of a connecting rod which allows for an additional degree of movement. The pivot assembly may include a thrust bearing (120) to further reduce friction on the connection rod.