Polygonal Shaft Retainer Ring for Hygienic Axial Locking
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Solution Overview
Problem
Existing retainer rings for conveyor components on shafts are not optimal for hygienic applications due to their difficulty in cleaning, as threaded components and set screws can harbor bacteria.
Innovation Solution
A retainer ring design featuring a series of N arcs that gradually decrease in distance from the center of a central bore, allowing for secure mounting on N-sided polygonal shafts without the need for grooves or threads, using a pair of rings to restrict axial movement and a specialized spanner wrench for tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If threaded retainer rings or set screws are used to secure components on a shaft, then the component is firmly held in place, but the threaded components and grooves create difficult-to-clean surfaces that harbor bacteria
Solution Approach 1:
The invention removes all threaded elements, set screws, and grooves from the retainer ring design. Instead, it uses a smooth-bore retainer ring that fits over a polygonal shaft, eliminating the complex geometric features that create cleaning difficulties while maintaining secure component retention through the polygonal interface.
Solution Approach 2:
Rather than creating grooves and threads in the retainer ring to secure it to the shaft, the invention inverts the approach by giving the shaft a polygonal cross-section and having the retainer ring conform to this external geometry. This reversal places the retention features on the shaft rather than the retainer ring, resulting in a smooth, cleanable retainer ring surface.
2Object-affected harmful factors
If smooth retainer rings without grooves or threads are used, then cleaning is easier and bacterial harborages are prevented, but the component may not be securely held in place
Solution Approach 1:
The invention employs asymmetric geometry by using an N-sided polygonal shaft cross-section that does not match the circular bore of the retainer ring. This asymmetric interface prevents rotation and secures the component firmly while keeping the retainer ring's outer surface smooth and cleanable.
3Reliability
If conventional retainer rings with grooves are used on round shafts, then component axial movement is restricted, but the grooves and threaded elements create complex geometries that are difficult to manufacture and clean
Solution Approach 1:
The polygonal shaft serves multiple functions: it provides the retention interface for the retainer ring, eliminates the need for separate grooves or threads, and creates a cleanable surface. The single geometric feature (polygonal cross-section) accomplishes what previously required multiple complex features.
Data Source
AI summary
Retainer rings for locking in an N-sided shaft to restrict axial movement of components sandwiched between them. The retainer rings have inner edges bounding a central bore. The inner edges are defined by a series of N arcs whose distance from the bore's center decreases gradually along the inner edge from a first end to a second end of each arc. The rings are slid on to the shaft with the corners of the shaft aligned with the first ends of the arcs. Then the rings are rotated on the shafts toward the second ends of the arcs until the corners of the shafts jam against the inner edges. A special spanner wrench can be used to tighten and loosen the rings on the shaft.