Freezer Door Baffle Mounting Pocket for Heat-Cycle Reliability
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Solution Overview
Problem
The metal-to-plastic threaded interface between the cantilevered baffle and the freezer door in frozen dessert machines experiences high failure rates due to mechanical stress from daily heat treatment cycles, leading to degradation of the plastic door over time.
Innovation Solution
A novel mechanical interface assembly featuring a recessed mounting pocket with a cornice on the freezer door and a retention flange on the baffle, both made from molded plastic, such as Delrin, providing a plastic-to-plastic detachable connection that reduces stress and fatigue, enhancing the blending of dessert products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal-to-plastic threaded interface is used to attach the baffle to the freezer door, then the baffle can be securely affixed to the door, but the plastic door degrades over time due to mechanical stress from daily heat treatment cycles
Solution Approach 1:
The patent applies the homogeneity principle by making both the baffle and the mounting pocket from the same plastic material (Delrin). This eliminates the metal-to-plastic interface that caused differential thermal expansion and mechanical stress. The uniform plastic-to-plastic connection allows both components to expand and contract together during heat treatment cycles, preventing the degradation and failure that occurred with the metal threaded interface.
2Ease of operation
If a threaded interface is used to connect the baffle to the door, then the connection can be made and disassembled, but the threaded structure creates stress concentration points that accelerate plastic degradation
Solution Approach 1:
The patent applies segmentation by dividing the connection interface into two distinct elements: a retention flange on the baffle and a mounting pocket in the door. This flange-and-pocket interface provides a large surface area contact connection that distributes mechanical stress uniformly, eliminating the stress concentration points created by threaded interfaces. The segmented design maintains detachability while preserving structural integrity through the stress-distributing geometry.
3Strength
If the baffle is made from stainless steel, then it provides sufficient structural strength, but the metal-to-plastic interface fails during repeated thermal cycling
Solution Approach 1:
The patent applies parameter changes by transitioning the baffle material from metal to plastic (Delrin), fundamentally changing the thermal and mechanical parameters of the component. This material parameter change allows the baffle to have compatible thermal expansion characteristics with the plastic door, eliminating the harmful thermal stress that caused interface failure. The plastic material maintains sufficient structural strength while being thermally compatible with the door assembly.
Data Source
AI summary
An interface assembly for a frozen dessert machine is disclosed that includes a freezer door having opposed front and rear sides and including at least one recessed mounting pocket formed in the rear side thereof, the at least one recessed mounting pocket including a cornice covering an upper portion thereof, and at least one elongated baffle having opposed proximal and distal end portions, the proximal end portion of the at least one baffle including a retention flange that is dimensioned and configured for detachable reception within the at least one mounting pocket of the freezer door behind the cornice.