Lever Actuated Door Latch Operator for Multipoint Locks
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Solution Overview
Problem
Multipoint door lock assemblies require a significantly increased manual effort to retract multiple latch bolts, making it difficult for individuals with limited physical strength to open the door, especially in higher-end hardware designs with large fixed handles and small thumb-depressed levers.
Innovation Solution
An improved door latch operator featuring an elongated hand grip style actuator lever that pivots toward a fixed handle to operate a torque converter or cam module, converting linear motion into rotary displacement to retract multiple latch bolts with minimal manual force, providing a mechanical advantage and intuitive operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multipoint lock assembly with multiple latch bolts is used, then door security and engagement are improved, but the manual force required to retract the latch bolts increases significantly
Solution Approach 1:
A cam mechanism is introduced as an intermediary between the lever handle and the latch bolts. When the lever is rotated, the cam converts this rotational motion into linear motion that simultaneously retracts all multiple latch bolts. This mechanical intermediary amplifies the user's input force and distributes it to move all latch bolts, solving the problem of high manual force requirement while maintaining the security benefits of multipoint locking.
Solution Approach 2:
The system uses a dynamic cam mechanism that transforms the static force application into dynamic motion. As the lever rotates through its arc, the cam profile dynamically controls the retraction sequence and force distribution across multiple latch bolts, allowing a relatively small rotational input to produce the necessary force to move all latch bolts simultaneously.
2Device complexity
If a small thumb-depressed lever actuator is used in higher-end hardware, then the design is more decorative and compact, but it becomes difficult for persons with limited physical strength to operate
Solution Approach 1:
The actuator lever transforms a simple thumb-depression motion into a rotational cam action. This dynamic transformation allows the lever to generate amplified force through the cam mechanism, enabling users with limited hand strength to easily retract multiple latch bolts. The lever maintains the compact, decorative design while improving operability through mechanical advantage.
Solution Approach 2:
The cam mechanism changes the force parameters by providing mechanical advantage. The cam profile is designed to multiply the input force from the lever, converting a small decorative lever into a high-force actuator capable of moving multiple latch bolts. This parameter transformation allows the same compact design to serve both aesthetic and functional requirements.
3Productivity
If multiple latch bolts are retracted concurrently, then door opening speed is improved, but the actuation mechanism becomes more complex
Solution Approach 1:
The cam mechanism merges the actuation of multiple latch bolts into a single rotational motion of the lever. Instead of requiring separate actuators for each latch bolt, the cam profile is designed to simultaneously engage and retract all latch bolts through one continuous motion, achieving fast door opening while minimizing mechanism complexity.
Solution Approach 2:
The single cam mechanism serves multiple functions: it simultaneously actuates all latch bolts, converts rotational to linear motion, and provides force amplification. This multi-functional design achieves concurrent latch bolt retraction without proportionally increasing the complexity of the actuator mechanism.
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 quick and easy opening of the door using a modest manual force, facilitating operation by virtually any user, including those with limited strength, while maintaining enhanced security features of multipoint lock systems.
Implementation Method 1
converting linear motion into rotary displacement to retract multiple latch bolts with minimal manual force, providing a mechanical advantage
Data Source
AI summary
A door latch operator includes a hand grip actuator lever for retracting one or more latch bolts mounted at a free side edge of a door, such as an entry door for a residence or place of business. The actuator lever is pivotally mounted at an inboard side of a manually grasped handle for grasping and squeezing with the fingers against the door handle to operate a torque converter or cam module for indexing a rotary cam through a rotary step. The rotary cam is coupled to a latch bolt retractor mechanism for retracting the latch bolt or bolts and thereby permit opening of the door. In a preferred form, the latch bolt retractor mechanism operates multiple latch bolts mounted along the free side edge of the door.