Plastic Tub Damper Mount Using Friction Torque Transfer
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Solution Overview
Problem
Existing plastic tubs in washing machines face challenges in transmitting torque for effective imbalance absorption due to the limitations of plastic materials in withstanding the required forces, leading to potential damage and rapid prestress relaxation, which is not adequately addressed by prior solutions like expansion sleeve fastening devices.
Innovation Solution
A fastening device with an S-shaped molded part and a holding device for the nut, which allows for precise adjustment of torque transmission through frictional engagement on the inside of the tabs, using a preload force that does not cause permanent deformation, and includes features like a resilient molded part for secure positioning and a cage-like holding device to prevent twisting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a heavily bolted connection is used to transmit torque, then torque transmission capability is improved, but the plastic material is damaged and prestress relaxation occurs rapidly
Solution Approach 1:
The invention changes the physical state of the fastening element from rigid (metal) to elastic (rubber or plastic material), allowing the material to deform elastically under preload and maintain continuous contact pressure without permanent deformation. This elastic deformation enables the plastic tub to withstand the required forces while avoiding damage and prestress relaxation.
Solution Approach 2:
The fastening element is made of composite material properties combining elasticity and friction-based force transmission. The elastic material (rubber or plastic) provides both the necessary compliance to avoid damaging the plastic tub and the frictional engagement to transmit torque effectively, creating a hybrid solution that addresses both torque transmission and material protection.
2Stability of the object's composition
If an expansion sleeve fastening device is used to stiffen the pivot axis, then vibration damping is improved, but the solution cannot be applied to plastic tubs with tabs
Solution Approach 1:
The invention changes the material properties from rigid expansion sleeves to elastic fastening elements made of rubber or plastic material. This allows the fastening element to conform to the plastic tab geometry and provide both stiffness and adaptability, enabling application to plastic tubs while maintaining vibration damping performance.
Solution Approach 2:
The fastening element uses flexible elastic material (rubber or plastic) that can deform and conform to the tab geometry, providing a secure fit on plastic tubs. This flexible material maintains contact pressure and frictional engagement while adapting to the specific geometry of the plastic tab, enabling universal application across different plastic tub designs.
3Reliability
If more parts are used for secure attachment, then reliability is improved, but assembly time and complexity increase
Solution Approach 1:
The invention merges multiple functions into a single integrated fastening element: the elastic material provides both the frictional engagement for force transmission and the elastic deformation for maintaining contact pressure. This unified component eliminates the need for separate washers, lock nuts, or adjustment mechanisms, reducing part count while maintaining secure attachment reliability.
Solution Approach 2:
The elastic fastening element is self-adjusting and self-securing. When installed, it automatically deforms to conform to the tab geometry and maintains continuous contact pressure through its elastic recovery. This self-service mechanism eliminates the need for additional adjustment parts or complex assembly procedures, reducing assembly time while ensuring reliable attachment.
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
This solution enables reliable and stable attachment of vibration dampers, reducing parts and assembly time, and effectively transmits torque forces without damaging the plastic tub, ensuring high imbalance absorption and vibration damping.
Implementation Method 1
The forces are intercepted or transmitted via frictional engagement on the inside of the tabs formed on the tub. This happens via the preload force of the screw.
Implementation Method 2
The load on the plastic and ultimately the amount of torque that can be transmitted can be adjusted precisely and reliably using the sleeve or collar of the screw or nut.
Implementation Method 3
The purpose of vibration dampers on oscillating units in automatic washing machines is to dampen movement in the event of an imbalance caused by laundry and to prevent the appliance from hitting or shifting.
Data Source
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AI summary
A front-load washing machine has a drum rotating within a plastic housing supported by a rubber bearing with a vibration dampener (6). The vibration dampener is secured to the plastic housing by two tabs (8, 9) with aligned holes. The two tabs sandwich an attachment eye (13) forming part of the oscillation dampener. The sandwich arrangement is secured by an S-shaped fixture (15) having holes (16, 17) in-line. The s-shaped fixture has a first U-shaped section (18) and sandwiched by the tabs (8, 9). The second curved section (19) extends beyond the outer tab end.