Household Appliance Door-Lock with Gear-Based Force-Reducing Mechanism
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Solution Overview
Problem
Existing door-lock mechanisms for household appliances, such as washing machines, fail to efficiently unlock when the laundry load applies high force, requiring significant user effort or service intervention due to friction and force transfer issues between components.
Innovation Solution
A door-lock design incorporating a force-reducing mechanism with a double gear wheel system and an oscillating locking pin, which reduces the friction and force required to unlock the door by using a solenoid actuator and a bi-stable spring mechanism to facilitate easy unlocking even under high load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional door-lock mechanism is used, then the door can be locked securely, but significant force is required to unlock when high laundry loads are present due to friction and force transfer issues
Solution Approach 1:
A force-reducing mechanism is introduced as an intermediary between the locking pin and the cam assembly. This mechanism includes a lever arm that pivots about an axis, where the locking pin applies force at one end and the cam assembly is actuated at the other end. The lever arm multiplies the unlocking force, reducing the effort required by the actuator while maintaining secure locking capability.
Solution Approach 2:
The locking pin is designed to oscillate in an arcuate path rather than moving in a straight line. This arcuate movement allows the locking pin to engage and disengage from the cam assembly more effectively, reducing friction during the unlocking process while maintaining reliable locking engagement.
2Device complexity
If the locking pin moves perpendicularly to the main slider, then the locking mechanism can be compact, but friction increases between the pin and slider contact surfaces
Solution Approach 1:
The locking pin is designed to oscillate dynamically in an arcuate path rather than moving statically in a fixed perpendicular direction. This dynamic movement allows the pin to maintain optimal contact angles with the cam assembly throughout the locking and unlocking cycles, reducing friction forces while preserving the compact mechanism arrangement.
3Device complexity
If a simple locking mechanism is used, then the device complexity is reduced, but the mechanism cannot handle high laundry loads exceeding 250 N
Solution Approach 1:
The force-reducing mechanism serves as an intermediary that allows a relatively simple actuator to control a much stronger locking system. The lever arm mechanism amplifies the actuator's force output, enabling the simple locking mechanism structure to handle high laundry loads exceeding 250 N without requiring a complex or oversized actuator.
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
Enables effortless unlocking of the door even under high laundry loads, preventing door-locking issues and reducing the need for service calls by minimizing friction and force requirements.
Implementation Method 1
an actuator (64) including a locking pin (44) adapted to lock the locking slider (40) in the locking position
Implementation Method 2
a cam (20) rotatable relative to the housing (16) about an axis of rotation between a retaining position and a release position
Data Source
Figure 1
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Figure 3
AI summary
Door-lock for household appliances, comprising: - a housing (16) having an opening for the insertion of a hook (24) carried by the door of the appliance, - a cam (20) rotatable relative to the housing (16) about a first axis (A) between a retaining position and a release position, wherein in the retaining position the cam (20) is adapted to lock said hook (24) in a closed-door position, a main slider (40) cooperating with said cam (20) and movable between a release position and a locking position, wherein in the release position the cam (20) is free to rotate around said first axis (A) and wherein in the locking position the main slider (40) locks the cam (20) in the retaining position, - a locking pin (44) adapted to lock the main slider (40) in the locking position, and ~ a force-reducing mechanism (46) arranged between the main slider (40) and the locking pin (44) and operating to reduce the locking force transferred from the main slider (40) to the locking pin (44), wherein the force-reducing mechanism (46) comprises a locking wheel (56) connected to said main slider (40) through a chain of gear wheels (52, 54, 58), and wherein said locking pin (44) cooperates with said locking wheel (56).