Closing device for drawers
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Solution Overview
Problem
Existing self-closing drawer slides experience abrupt transition forces and noise due to linearly increasing spring force, which is undesirable and can cause contents to shift abruptly, especially in heavy-duty applications where higher spring forces are required.
Innovation Solution
A closing device with a mechanical advantage mechanism that alters the biasing force applied to the latch non-linearly, using a combination of a first biasing member and a gear to modulate the force applied to the rack body, allowing for a reduced rate of force increase as the latch approaches its locked position, and optionally incorporating a damper for smoother operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring with linearly increasing force is used to assist drawer closing, then the drawer can be pulled to a fully closed position and rebounding is prevented, but the force transmitted to the user becomes abrupt and unsettling at the transition point
Solution Approach 1:
The patent changes the force parameter from linear to non-linear by introducing a mechanism where the spring force is applied through a lever arm that rotates. The effective force transmitted to the latch varies with the angle of rotation, creating a non-linear force profile that reduces abrupt transitions while maintaining reliable closing assistance.
Solution Approach 2:
The patent introduces dynamic elements including a rotating lever arm and a movable latch that transitions between locked and unlocked positions. The system dynamically adjusts the force transmission ratio during operation, allowing smooth modulation of the spring force rather than direct linear application.
2Reliability
If a latch mechanism with direct spring connection is used, then the drawer can be held in closed position, but the engagement and disengagement produces noise and abrupt motion
Solution Approach 1:
The patent introduces a lever arm as an intermediary between the spring and the latch. This lever arm rotates about a pivot point and provides a mechanical advantage that gradually engages and disengages the latch, smoothing out the interaction and reducing impact forces that cause noise and vibration.
Solution Approach 2:
The patent designs the latch engagement mechanism to gradually approach the locked position rather than sudden impact. The rotating lever arm allows the latch to be gently guided into engagement, cushioning the transition before full locking occurs, thereby reducing harmful impacts and noise.
3Force
If a heavy-duty spring with high force is used, then the drawer can be reliably closed against heavy loads, but the abrupt transition forces increase and cause contents to shift
Solution Approach 1:
The patent transforms the direct linear force application into a rotational moment application. The spring force is converted into a torque on the lever arm, which then translates to a gradually increasing force on the latch as the rotation progresses. This parameter transformation allows high spring forces to be used without creating abrupt linear accelerations that would destabilize drawer contents.
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 provides a smooth and quiet closing mechanism for heavy-duty drawer slides by reducing the abrupt transition forces and noise, maintaining a consistent force profile during the closing process, ensuring the drawer is gently guided to a fully closed position without sudden jerks or shifts.
Implementation Method 1
a first biasing member connected at a first end to the base and at an opposed second end to the rack body, and biasing the rack body to move rearward relative to the base
Implementation Method 2
the rack and gear engagement provides a mechanical advantage that alters the biasing force applied to the rack body by the second biasing member in a non-linear manner upon movement of the rack body relative to the base
Data Source
AI summary
A closing device includes a rack body having an elongated rack and being slidably coupled to a base, with a catch pivotally coupled to the rack body and a gear pivotally coupled to the base and engaging the elongated rack. A first biasing member is coupled to the base and rack body and provides a substantially linear biasing force. A second biasing member is coupled to the base and gear, and the elongated rack and gear engagement provides a mechanical advantage and a non-linear biasing force. The closing device is for use in a drawer slide having a latch coupled to a first drawer slide member and the base coupled to a second drawer slide member, with the latch releasably coupled to the catch to move the drawer slide to a closed position.