Elevator Door Motor Brake for 50 mm Opening Limit Control
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Solution Overview
Problem
Existing elevator systems require frequent adjustments and maintenance of mechanical deterrent devices to limit elevator car door opening, which conflicts with manufacturer initiatives to reduce external maintenance, especially with new regulatory requirements setting a 50 mm opening limit.
Innovation Solution
An elevator system incorporating a door motor brake mechanism, including a movable pin with an electrical coil and biasing member, selectively engages with the elevator door motor to prevent undesired opening or closure of the elevator car door, allowing for precise control of the door opening width without external adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical deterrent device (cam and roller arrangement) is used to prevent elevator car door opening, then the door opening is limited, but the device requires frequent adjustments and maintenance from outside the elevator car
Solution Approach 1:
The patent replaces the external mechanical deterrent device (cam and roller arrangement) with an internal door motor brake system that uses electromagnetic braking mechanisms. The brake assembly includes a brake disc attached to the door motor shaft and a brake caliper with friction pads that can be actuated by the control system to prevent door motor operation, thereby eliminating the need for external mechanical devices and their associated maintenance requirements
Solution Approach 2:
The invention extracts the deterrent function from the external mechanical device and relocates it to the door motor itself by integrating a brake assembly. This extraction moves the prevention mechanism from an external cam-and-roller system to an internal electromagnetic brake system that can be controlled directly by the elevator control system
2Manufacturing precision
If the opening limit is reduced to 50 mm per new code requirements, then regulatory compliance is achieved, but the mechanical deterrent device requires more frequent adjustments to maintain the stricter limit
Solution Approach 1:
The patent replaces the mechanical adjustment-based cam and roller system with an electronically controlled brake assembly. The brake can be actuated by the control system to precisely limit door opening to 50 mm without requiring physical adjustments to the mechanical components, as the braking force can be modulated electronically to maintain the precise opening limit
Solution Approach 2:
The invention introduces dynamic control of the door opening limit through an adjustable brake assembly that can be actuated at different times and with different forces based on real-time operational conditions. The brake assembly includes a movable brake caliper that can be positioned along the brake disc to adjust the braking point, allowing dynamic adaptation to maintain the 50 mm limit without mechanical reconfiguration
3Reliability
If a mechanical deterrent device is installed on the outside of the elevator car, then door opening prevention is achieved, but it conflicts with manufacturer initiatives to reduce external maintenance activities
Solution Approach 1:
The invention extracts the deterrent function from external mechanical devices and relocates it to the internal door motor assembly. The brake assembly is integrated into the door motor housing and can be serviced from inside the elevator car, eliminating the need for external maintenance activities while maintaining door opening prevention functionality
Solution Approach 2:
The patent merges the deterrent function with the door motor assembly by integrating the brake assembly directly onto the motor shaft. This combination eliminates the separate external mechanical deterrent device and consolidates the prevention function within the existing motor housing, allowing all maintenance to be performed from inside the elevator car
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 door motor brake system effectively prevents elevator car door opening beyond the specified limit, reducing maintenance needs and aligning with regulatory requirements while minimizing external interference.
Implementation Method 1
an electrical coil disposed at the pin to urge movement of the pin between an extended position in engagement with the elevator door motor and a retracted position out of engagement with the elevator door motor
Implementation Method 2
a biasing member to urge the pin into engagement with the elevator door motor
Implementation Method 3
a door motor brake disposed at the elevator car door and selectably engageable with the elevator door motor to prevent operation of the elevator door motor
Data Source
AI summary
An elevator system includes a hoistway; and an elevator car (12) disposed in and drivable along the hoistway, the elevator car including: an elevator car door (38); an elevator door motor (40) operably connected to the elevator car door to selectably open and close the elevator car door; and a door motor brake (52) disposed at the elevator car door and selectably engageable with the elevator door motor to prevent operation of the elevator door motor thus preventing undesired opening and/or closure of the elevator car door.