Shoulder Bushing Hinge Assembly for Damped Appliance Door Closure
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Solution Overview
Problem
Heavy domestic appliance doors often slam shut due to strong springs, causing noise, potential damage, and a perception of low quality, which is undesirable, and existing soft-close hinges require a secure pivot point to manage damper and spring forces effectively.
Innovation Solution
A hinge assembly with a shoulder bushing and a damper system that includes a coil spring and a rod within a cylinder, where the foot is pivotably attached to the damper and engages a foot receiving portion on the appliance body, using a shoulder bushing with a large and small diameter portion to securely locate the pivot point, resisting forces and ensuring smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a strong spring is used to counteract door weight, then the door becomes easier to open, but the door slams shut causing noise and potential damage
Solution Approach 1:
The damper is positioned to apply a counteracting damping force before the door reaches the closed position, preventing the slamming action from occurring in the first place. The damper rod and cylinder arrangement creates resistance that opposes the spring's closing force as the door approaches closure.
Solution Approach 2:
The damper system provides cushioning force in advance of the door closure event. By positioning the damper to engage before the door reaches the closed position, it gradually reduces the door's kinetic energy and prevents the harmful impact that would occur without this preliminary cushioning action.
2Object-affected harmful factors
If a damper system is added to prevent slamming, then door closure quality improves, but the pivot point requires stronger locating to resist increased forces
Solution Approach 1:
The shoulder bushing provides localized strengthening at the pivot point where the foot attaches to the hinge body. By concentrating the locating and support function at this specific location with a bushing that has a larger diameter than the pivot pin, the design strengthens only where needed rather than requiring overall reinforcement of the entire hinge assembly.
Solution Approach 2:
The shoulder bushing acts as an intermediary element between the pivot pin and the hinge body. It mediates the forces transmitted through the pivot point, distributing the loads from the damper and spring forces across a larger area of the hinge body, thereby protecting the pivot structure from excessive point loads.
3Ease of manufacture
If the pivot point is not securely located, then the hinge assembly is simpler to manufacture, but increased loads and noise occur due to pivot movement
Solution Approach 1:
Rather than requiring complex locating features throughout the hinge assembly, the design applies a simple shoulder bushing at the critical pivot point location. This localized approach provides the necessary stability and load distribution without adding complexity to the overall manufacturing process.
Solution Approach 2:
The shoulder bushing's geometry itself provides the locating function through its shoulder feature that contacts the hinge body. The bushing's own structure creates the necessary mechanical interference and positioning without requiring additional locating pins, slots, or complex alignment features, making it a self-sufficient locating solution.
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 solution prevents door slamming by damping the closing motion and provides a strong, secure pivot system that maintains consistent door closure time and ease of operation, reducing noise and wear, while ensuring the door remains aligned with the appliance body.
Implementation Method 1
a coil spring located inside the cylinder and around the rod
Implementation Method 2
the damper damping the movement of the rod relative to the cylinder
Implementation Method 3
a damper having a central longitudinal axis and including a damper cylinder attached to the hinge body, the damper cylinder having a rod partially located inside the cylinder
Data Source
AI summary
A hinge assembly is provided for attaching a door to a domestic appliance. The hinge assembly includes a hinge body; a damper; a foot pivotably attached to the damper and having a pivot end, the foot engaging a foot receiving portion of the appliance such that the hinge body and the door pivot relative to the appliance; and a shoulder bushing attached to the pivot end of the foot and to a pivot point of the hinge body such that the foot pivots relative to the hinge body around the pivot point, the shoulder bushing having a large diameter portion and a small diameter portion. The pivot end of the foot is fixed to the shoulder bushing at a fixing area of the small diameter portion such that a side surface of the pivot end of the foot is in contact with a side surface of the large diameter portion.