Cam Locking Mechanism for Door Driving Unit
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Solution Overview
Problem
Existing door driving units require a reversible screw and nut for locking, limiting their functionality if these components are not present, and lack an efficient mechanism to lock a door leaf in a door closing position.
Innovation Solution
A locking device with a cam mechanism that rotates about a center axis parallel to the door's opening width direction, allowing or prohibiting door movement based on its rotational position, and a rotation prohibiting portion to prevent door movement when the door is fully closed, integrated with a door driving unit that includes a base member and rotary moving unit to drive the door without a motor drive source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reversible screw and nut mechanism is used for locking, then the door can be locked and unlocked, but the device becomes complex and cannot function without these specific components
Solution Approach 1:
The patent extracts the essential locking function from the reversible screw-nut mechanism and implements it using a cam mechanism instead. The cam mechanism achieves the same locking and unlocking functionality without requiring a reversible screw and nut, thereby simplifying the overall device structure while maintaining reliability.
Solution Approach 2:
The cam mechanism serves multiple functions: it provides locking when engaged, allows movement when disengaged, and can be actuated by various means (manual or automated). This universal approach replaces the specialized reversible screw-nut mechanism with a more versatile solution that works without those specific components.
2Ease of operation
If a cam mechanism is used to control door movement, then the door can be locked easily, but additional components are needed to prohibit rotation at the closed position
Solution Approach 1:
The patent merges the cam mechanism with a rotation prohibition feature by integrating the second cam (rotation prohibiting portion) with the rotating unit structure. This combination achieves both the locking function and the rotation prohibition function within a unified mechanism, preventing door movement at the closed position without adding entirely separate components.
3Reliability
If a motor-driven base member is used to prohibit rotation, then the door closing position can be controlled, but the device becomes more complex
Solution Approach 1:
The base member acts as an intermediary element that transmits the motor's driving force to the rotating unit. By using the base member as a mediator, the system achieves reliable door positioning and rotation control without requiring direct motor connection to the locking mechanism, thereby distributing complexity across multiple simpler 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 of the door leaf regardless of the presence of a reversible screw and nut, and allows for efficient door closure with a compact structure by prohibiting rotation of the cam mechanism when the door is fully closed, ensuring the door remains locked with a simple and small-sized mechanism.
Implementation Method 1
a cam (82) formed in a rotating unit (81) configured to rotate about a rotational center axis (CB) that is parallel to an opening width direction (DT) of a door (3), the cam (82) being configured to permit or prohibit movement of a door leaf (3) in the opening width direction (DT) in accordance with a rotational position of the rotating unit (81)
Implementation Method 2
the cam (82) has a cam surface (82A) configured to contact with a contact portion (3A) that moves together with the door leaf (3), and the cam surface (82A) is configured to advance in a direction in which the contact portion (3A) enters, while turning about the rotational center axis (CB)
Implementation Method 3
The locking device further comprises a rotation prohibiting portion (81A) for prohibiting rotation of the rotating unit (81) at such a position as to prohibit the movement of the door leaf (3) when the door leaf has reached a door closing position
Implementation Method 4
the base member is capable of moving in an opening direction (DTA) of the door leaf (3) by a drive force of a motor when the door leaf has reached a door closing position, and the base member moving in the opening direction of the door leaf contacts with a rotation prohibiting portion (81A) for prohibiting rotation of the rotating unit (81), thereby to prohibit the rotating unit from rotating
Data Source
AI summary
A locking device includes a cam that is formed in a rotating unit configured to rotate about a rotational center axis that is parallel to an opening width direction of a door, and the cam permits or prohibits movement of a door leaf in the opening width direction in accordance with a rotational position of the rotating unit.