Cam-Spring Door Hinge for Balanced Closure and Low Switch Force
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Solution Overview
Problem
Current hinges for top loading washing machines either require high force to open/close the door and activate/deactivate an electromechanical switch or allow the door to close at high speeds, posing safety risks.
Innovation Solution
A hinge design featuring a cam-shaped lever with a pre-compressed helical spring and wheel system that adjusts door movement, balancing the door's opening/closing action while reducing the force needed to activate an electromechanical switch by varying the lever arm length based on the door's angle, allowing the door's weight to assist in closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hinge provides strong balancing action to balance the door for most of its opening/closing angle, then the door is balanced, but high force is required to activate the electromechanical switch
Solution Approach 1:
The hinge employs a cam mechanism with an asymmetric profile that dynamically adjusts the lever arm length throughout the door's opening/closing range. The cam's varying radius creates a non-uniform mechanical advantage, providing strong balancing force during most of the motion range while reducing force requirement near the closed position for switch activation.
Solution Approach 2:
The invention changes the geometric parameter of the lever arm length dynamically through the cam mechanism. By varying the perpendicular distance from the pivot axis to the spring force application point, the system adjusts the mechanical advantage ratio, enabling strong balancing action during most of the range and reduced force near the closed position.
2Force
If the hinge provides slight balancing action to reduce force for switch activation, then the switch is easy to activate, but the door acquires high closing speed posing safety risks
Solution Approach 1:
The cam mechanism dynamically modulates the balancing force throughout the door's motion. During the closing phase, the cam profile maintains a longer lever arm for most of the range, providing sufficient balancing to control door speed and prevent dangerous closing velocities, while allowing reduced balancing near the closed position for easy switch activation.
Solution Approach 2:
The varying lever arm length parameter, controlled by the cam profile, enables the hinge to provide appropriate balancing force at different positions. The geometric design ensures that the lever arm remains sufficiently long during the closing motion to limit speed, then shortens near the closed position to reduce activation force.
3Device complexity
If the lever arm length is kept constant to simplify the structure, then the structure is simple, but the force required to operate the switch remains high
Solution Approach 1:
The invention employs a cam-shaped lever with a curved, asymmetric profile instead of a straight rigid lever arm. This curved geometry allows the perpendicular distance from the pivot axis to the spring force application point to vary continuously, creating the desired variable mechanical advantage while maintaining a relatively simple single-piece lever 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 hinge balances door movement for most of its opening/closing angle, reducing the force required to operate the switch and preventing high-speed closure, enhancing safety and usability.
Implementation Method 1
there is provided a pre-compressed elastic element, preferably a helical spring, acting on a cam-shaped lever
Implementation Method 2
reducing the force needed to activate an electromechanical switch by varying the lever arm length based on the door's angle
Implementation Method 3
allowing the door's weight to assist in closure
Data Source
AI summary
A hinge for doors, in particular for electrical appliances, comprises a box-shaped body (3), a lever (4) pivoting at the box-shaped body (3) at a respective axis (A) of rotation so that the body (3) and the lever (4) can move relative to each other by tilting, the box-shaped body (3), a spring (12) housed in the box-shaped body (3) and designed to operate in conjunction with a first portion (4a) of the lever (4) to adjust the motion of the lever (4) and the box-shaped body (3) relative to each other.