Motorized Drawer Locking with Planetary Gear Self-Reset
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Solution Overview
Problem
Conventional drawer apparatuses in POS systems require position control and motor stop control for accurate locking and unlocking, increasing complexity and cost due to the need for sensors and control boards.
Innovation Solution
A drawer apparatus using a motor with a planetary gear system that allows unidirectional rotation to engage and disengage the lock without position control, eliminating the need for motor reverse control and sensor detection, and utilizing a simple configuration like a spring to operate the locker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a solenoid actuator is used for the locking mechanism, then the drawer can be locked and unlocked, but it produces metallic collision sound and requires power supply more than 5V
Solution Approach 1:
The patent replaces the solenoid actuator with a DC motor that drives a planetary gear mechanism. This mechanical substitution eliminates the metallic collision sound produced by solenoid plunger impact while maintaining the locking and unlocking functionality. The motor-driven system operates silently compared to the solenoid's audible mechanical impact.
2Reliability
If position control and motor stop control are implemented for accurate locking and unlocking, then the locking mechanism works reliably, but the device complexity increases due to sensors and control boards
Solution Approach 1:
The planetary gear mechanism is designed to automatically achieve accurate positioning and reliable locking/unlocking without requiring external position sensors or complex control algorithms. The mechanical structure itself provides the necessary precision through its inherent geometry and engagement features, allowing the system to be self-sufficient in achieving reliable operation.
Solution Approach 2:
The motor operates in periodic cycles: driving the planetary gear to engage the lock, pausing for engagement, then reversing to disengage. This periodic operation pattern allows reliable locking and unlocking through simple on/off control without requiring continuous position feedback or complex stop control mechanisms.
3Reliability
If a motor with position control is used, then the drawer can be locked and unlocked reliably, but it increases the number of components and cost
Solution Approach 1:
The patent extracts and eliminates unnecessary control components (position sensors, control boards, complex drive circuits) from the system. By using a simple DC motor with planetary gear mechanism that inherently provides reliable locking/unlocking through its mechanical design, the system achieves the same reliability with significantly fewer components.
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 locking and unlocking of the drawer without position control or motor stop control, reducing the number of components and costs, while maintaining the silence characteristic and compatibility with USB bus power supply.
Implementation Method 1
a planetary gear unit to be shifted from a default state in which the base 63 is in abutment with the second stopper 431 to an engaged state in which the smaller-diameter planetary gear 622 is engaged with the gear 522 by rotation of the motor 81 in one direction
Implementation Method 2
The lock may be urged toward the transmitter in the locked state
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
The present invention provides a drawer apparatus capable of locking and unlocking a drawer without position control and motor stop control. A lock frame 7 is released from the hook 521 to be brought into an operable state by unidirectional rotation of a DC motor 81 in an engaged state. A drawer 2 is released from an anchor 72 to be advanced out of the retracted position when the lock frame 7 operates. A planetary gear unit 6 is pushed by the lock frame 7. A small-diameter planetary gear 622 is thereby shifted from the engaged state to a default state. The anchor 72 is engaged with the drawer 2 when the advanced drawer 2 is pushed back to the retracted position. The hook 521 is engaged with a lock 71 when the advanced drawer 2 is pushed back to the retracted position.