Nutating Sprinkler Spool Assembly Tilting Lugs
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Solution Overview
Problem
Conventional rotary sprinkler heads often experience stalling issues at start-up and during operation, leading to a 'donut effect' due to the water-deflection plate failing to tilt or cease tilting, resulting in non-uniform watering patterns.
Innovation Solution
A rotary, nutating sprinkler head design featuring a housing with a spool assembly including a double-flanged spool and water-deflection plate, loosely supported on a starter tube with tilting lugs to maintain a tilted orientation, and an annular race for engagement during rotation, ensuring consistent wobbling action and uniform watering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the sprinkler operates as a conventional rotary type, then the structure is simple, but it creates a donut pattern with a dry area inside
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static rotary sprinkler to a dynamic nutating sprinkler. The water-deflection plate is designed to tilt and wobble during rotation, creating a nutating motion that dynamically redistributes water to eliminate the donut pattern while maintaining manufacturing feasibility through the spool-and-flange mechanism.
Solution Approach 2:
The patent segments the water-deflection plate into multiple functional zones with different groove orientations and angles. This segmentation allows different portions of the plate to deflect water in varying directions, creating a more uniform watering pattern that covers both the outer and inner areas effectively.
2Reliability
If the water-deflection plate is designed to wobble, then uniform watering pattern is achieved, but stalling occurs at start-up or during operation
Solution Approach 1:
The patent applies preliminary action by incorporating start-up lugs that pre-position the water-deflection plate in a tilted orientation before rotation begins. These lugs engage with the spool flanges to ensure the plate starts in the correct nutating position, preventing stalling and ensuring immediate wobbling action upon activation.
Solution Approach 2:
The patent implements feedback through the interaction between the spool flanges, start-up lugs, and running lugs. The lugs provide mechanical feedback that maintains the tilted orientation of the water-deflection plate during operation, automatically correcting any deviation from the proper nutating position and preventing stalling.
3Measurement precision
If the spool assembly is tightly fixed, then positioning is precise, but the nutating action becomes restricted
Solution Approach 1:
The patent applies local quality by providing different degrees of constraint at different locations of the spool assembly. The start-up lugs provide localized positioning accuracy at specific points on the spool flanges, while allowing freedom of motion in other areas to enable the nutating action. This selective constraint approach maintains both precision and wobbling freedom.
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 ensures reliable and consistent wobbling action, preventing the 'donut effect' by maintaining the water-deflection plate in a tilted orientation, resulting in uniform watering patterns and improved operational stability.
Implementation Method 1
the water-deflection plate formed with one or more grooves shaped to cause the spool assembly to rotate when impinged upon by a stream emitted from the starter tube
Implementation Method 2
one of the starter tube and the spool is provided with at least one tilting lug located to maintain the spool assembly in a tilted or angularly offset orientation relative to the vertical center axis
Data Source
AI summary
A rotary, nutating sprinkler head includes a housing supporting a nozzle tube extending in a downstream direction, concentric with a vertical center axis of the sprinkler head; a spool assembly loosely supported on the starter tube, the spool assembly including a double-flanged spool and a water-deflection plate carried by the spool, the water-deflection plate formed with one or more grooves shaped to cause the spool assembly to rotate when impinged upon by a stream emitted from the starter tube; wherein one of the starter tube and the spool is provided with at least one tilting lug located to maintain the spool assembly in a tilted or angularly offset orientation relative to the vertical center axis, thereby facilitating a wobbling action of the spool assembly during rotation.