Locking Device Lever Transmission for Deep Bolt Engagement
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Solution Overview
Problem
Conventional locking devices for fire protection doors lack sufficient security and adaptability to ensure deep engagement of the bolt in the strike plate during door expansion or deformation, such as due to heat, and fail to provide easy conversion for different door sizes.
Innovation Solution
A locking device featuring a bolt drive designed as an espagnolette rod with a slotted or C-shaped end engaging a lever transmission gear, combined with a step-up gear between the drive bolt rod and bolt, allowing for increased stroke length and engagement depth, and equipped with a spring mechanism for automatic locking, enabling manual or motorized operation and easy adaptation to various door sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional locking device is used, then the structure is simple, but the bolt engagement depth is insufficient during door expansion or deformation
Solution Approach 1:
A lever transmission gear is introduced as an intermediary mechanism between the espagnolette rod and the bolt. The lever converts the limited movement of the espagnolette rod into a larger bolt stroke, enabling deep engagement in the strike plate even when the door expands or deforms due to heat, without requiring a completely complex locking device structure
Solution Approach 2:
The lever transmission gear provides dynamic adaptability by mechanically amplifying the bolt stroke based on the lever arm ratios. This dynamic mechanism allows the bolt to achieve greater travel distance than the espagnolette rod movement would normally permit, ensuring sufficient engagement depth under varying door conditions
2Reliability
If the bolt stroke is increased for deep engagement, then security against door warping is improved, but the device complexity increases
Solution Approach 1:
The lever acts as a mechanical intermediary that provides stroke multiplication. By positioning the pivot bearing and lever arms appropriately, the system achieves the required bolt stroke length for security against door warping while keeping the transmission mechanism relatively simple through geometric leverage rather than complex gearing
Solution Approach 2:
The lever transmission gear converts linear movement in one dimension (espagnolette rod movement) into amplified linear movement in the same dimension (bolt stroke) through rotational pivot movement, effectively using a different dimensional approach (rotation) to achieve linear displacement amplification
3Adaptability or versatility
If a fixed stroke locking device is used, then the structure is simple, but adaptability to different door sizes is poor
Solution Approach 1:
The locking device achieves adaptability to different door sizes through the dynamic lever transmission mechanism. By adjusting the pivot bearing position or lever arm dimensions, the stroke multiplication ratio can be varied to match different door widths and bolt stroke requirements, providing versatility without requiring a completely different locking device for each door size
Solution Approach 2:
The lever transmission gear provides universal adaptability by serving multiple functions: it multiplies the bolt stroke for deep engagement, accommodates different door sizes through geometric adjustment, and maintains a relatively simple overall structure. This single mechanism handles various door configurations that would otherwise require multiple specialized locking devices
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 ensures deep and secure engagement of the bolt in the strike plate, even during door deformation, and allows for easy conversion of conventional locking devices, providing enhanced security and adaptability for fire protection and burglary resistance.
Implementation Method 1
a lever acting as a transmission gear, one end of which pivots in a pivot bearing on the housing and the other end engages in a pivot bearing and a slot on the bolt
Implementation Method 2
the bolt is urged in the direction of the locking position by a push-out spring. This spring can be in the form of a torsion spring or a helical spring
Data Source
Figure 1~2
AI summary
The device (10) has a latch (12) i.e. safety catch, and a latch drive (25) for moving the latch between releasing and locking positions. The latch drive is operated manually or by a motor. A step-up gear (32) is arranged between the latch and latch drive. The latch drive is designed as a driving locking bolt (26) whose end (30) is designed in a slotted manner or in C-shape. A lever (34) works as the gear, where an end of the lever is supported at a pivot bearing (36) in a housing (14). Another end of the lever is attached to an elongated hole in the latch.