Toggle Lever Door Lock Reduces Release Force
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Solution Overview
Problem
Existing door locks with cross latches face issues with complex guidance and precise wedge angles in blocking mechanisms, leading to high release forces and potential jamming, especially when designed as panic locks where force limitations are critical.
Innovation Solution
A toggle lever arrangement with a first and second lever element connected via an articulated connection, allowing for low release force blocking and easy interaction with the cross latch, eliminating the need for a wedge surface and complex guidance, and utilizing a return spring for automatic retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamping element with a wedge surface is used to block the cross latch, then the cross latch can be held in the closed position, but the clamping element requires complex guidance in the housing and precise wedge angle manufacturing
Solution Approach 1:
The blocking device is divided into two separate lever elements (first lever element and second lever element) connected by an articulated connection. This segmentation eliminates the need for complex guidance of a single clamping element, as each lever element has simplified movement paths guided by basic guide elements and a guide contour in the housing.
Solution Approach 2:
The blocking device transitions from a static wedge surface to a dynamic toggle lever mechanism. The lever elements can pivot and change position dynamically, allowing the blocking function to be achieved through motion rather than fixed geometric precision, thereby reducing manufacturing tolerances and guidance complexity.
2Reliability
If a clamping element with a wedge surface is used to block the cross latch, then the cross latch can be held in the closed position, but a precise wedge angle must be manufactured with high precision
Solution Approach 1:
The static wedge angle is replaced by a dynamic lever mechanism where the blocking force is generated through the toggle action of the lever elements. This eliminates the need for precise wedge angle manufacturing, as the blocking function is achieved through the mechanical advantage of the lever arrangement rather than precise geometric angles.
Solution Approach 2:
The design changes from relying on a fixed geometric parameter (wedge angle) to relying on mechanical parameters (lever arm lengths, articulation points) that are less sensitive to manufacturing tolerances. The blocking force is generated through the toggle lever mechanism's mechanical advantage rather than precise angular geometry.
3Ease of operation
If the clamping element moves downwards during unlocking, then the cross latch can be released, but the slide element may touch the clamping element too early causing the cross latch wings to rotate excessively
Solution Approach 1:
The locking element is pulled back into the housing before the cross latch is released. This preliminary action ensures that the locking element is disengaged from the strike plate before the cross latch wings rotate, preventing excessive rotation and maintaining pressure relief throughout the unlocking sequence.
Solution Approach 2:
The unlocking sequence is made dynamic and sequential through the toggle lever mechanism. As the lever elements pivot during unlocking, they automatically coordinate the retraction of the locking element before full release of the cross latch, preventing premature contact and excessive rotation through the natural progression of the mechanical motion.
4Ease of operation
If the cross latch is unlocked and the locking element comes to rest against the striking plate, then friction and jamming occur, but normative force limits cannot be complied with
Solution Approach 1:
The locking element is retracted into the housing before the cross latch is fully released. This preliminary retraction eliminates friction and jamming against the strike plate, ensuring that the force required to unlock remains within normative limits by preventing the locking element from resting against the striking plate during the final stages of unlocking.
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 toggle lever arrangement effectively blocks the cross latch with a low release force, ensuring compliance with normative force limits and preventing jamming, while allowing easy retraction into the lock housing with minimal force.
Implementation Method 1
the cross latch can be pushed back into the housing 10 automatically, for example by manually moving the door away from the strike plate
Data Source
Figure 1
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Figure 3
AI summary
The lock (1) has a housing (10) in which a cross latch (11) is arranged in a movable manner in a pushing direction (12) such that the latch is brought into a closing position (I) and into an opening position in which the latch is drawn into the housing. A blocking device blocks the latch in the closing position. The blocking device is formed by a toggle lever arrangement (13), where the arrangement comprises two lever elements (14, 15) that are connected with one another over a joint connection (16). The latch works together with one of the lever elements.