Sprinkler Nutating Spool Tilting Lugs Wear Reduction
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Solution Overview
Problem
Conventional rotary sprinkler heads often experience stalling at start-up and during operation due to the water-deflection plate failing to tilt, leading to a 'donut effect' and excessive wear on wobbling/rotating surfaces, which reduces their effectiveness and wear life.
Innovation Solution
A rotary sprinkler head design featuring a double-flanged spool assembly with a water-deflection plate, loosely supported on a tube, and an annular race for rolling contact engagement, along with tilting lugs to maintain a tilted orientation and enhance wear life, and an optional weight for stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sprinkler operates as a conventional rotary design without tilting mechanism, then the structure is simple, but the water-deflection plate fails to tilt reliably causing stalling and donut effect
Solution Approach 1:
The spool assembly is pre-positioned in a tilted orientation relative to the nozzle axis before water flow begins. This preliminary tilting action is maintained through the engagement of the spool's flange with the raceway, ensuring the water-deflection plate is already in the correct angular position to create proper stream breakdown without stalling
Solution Approach 2:
The raceway acts as an intermediary element between the spool assembly and the housing. It provides a constrained path that maintains the spool's tilted orientation while allowing rotational movement, thereby ensuring reliable tilting action without requiring complex mechanical linkages or additional actuating mechanisms
2Device complexity
If sliding contact is used between spool flange and raceway, then the structure is simpler, but excessive wear occurs on the wobbling/rotating surfaces
Solution Approach 1:
The raceway is designed with a curved, arc-shaped cross-section that complements the curved outer surface of the spool flange. This spherical/curved contact geometry converts what would be sliding friction into rolling contact, significantly reducing wear on both the spool flange and raceway surfaces while maintaining the simplicity of the contact mechanism
Solution Approach 2:
The contact parameters between the spool flange and raceway are changed from sliding to rolling contact through the specific geometric design of the raceway's curved profile. This parameter change in the type of contact dramatically reduces wear rates, extending the duration of action of the stationary raceway and moving spool components
3Manufacturing precision
If the spool assembly is tightly constrained, then positioning precision is improved, but the wobbling action becomes unreliable and stalling occurs
Solution Approach 1:
The spool assembly is constrained in a dynamic manner that allows controlled movement. The curved raceway provides geometric constraints that maintain precise tilted positioning while simultaneously permitting the rotational and wobbling motions necessary for reliable operation. This dynamic constraint system prevents stalling by allowing the spool to self-adjust during rotation
Solution Approach 2:
The constraint parameters are optimized to provide precise positioning in the tilted orientation while maintaining sufficient clearance and freedom for wobbling motion. The curved profile of the raceway creates a balance between geometric constraint for positioning and mechanical freedom for motion, preventing both excessive play and binding
4Duration of action of stationary object
If rolling contact is implemented between spool flange and raceway, then wear life is improved, but the device complexity increases
Solution Approach 1:
The rolling contact is achieved through a relatively simple curved or arc-shaped raceway profile rather than complex roller or bearing assemblies. This curved geometry naturally facilitates rolling motion between the spool flange and raceway, providing extended wear life while adding minimal complexity to the overall device 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 design ensures reliable wobbling action, minimizes the 'donut effect', and significantly improves the wear life of sprinkler components by maintaining consistent tilting and reducing surface wear through rolling contact and stabilization.
Implementation Method 1
the spool assembly including a double-flanged spool and a water-deflection plate carried by the spool, downstream of the nozzle... 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
the running surfaces of the spool engage the annular race mainly via rolling contact (with only minimal sliding contact) to thereby improve the wear life of the components
Implementation Method 3
Mechanical elements such as lugs are located on either a flange on the tube or on an interior ring or disc on a lower portion of the spool for maintaining the spool assembly in a tilted or offset orientation relative to a longitudinal center axis through the sprinkler head
Data Source
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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 ac 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.