Lock Device Reducing Operating Load via Cam Deformation
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Solution Overview
Problem
Existing lock devices require a high operating load to shift from the unlocked to the locked condition, which can result in an insufficient engagement force between the striker and the lock mechanism, and reducing spring forces may compromise the locking engagement.
Innovation Solution
The lock device features a base plate with a recess, a hook, a pawl, a lock spring, and a cam with a deformation promoting portion, where the first and second contact points are set at different positions to reduce the operating load while maintaining the engagement force, and the cam deforms before other components to maintain the locked condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spring forces are increased to maintain sufficient engagement force between the lock mechanism and the striker, then the engagement force is improved, but the operating load required to shift from unlocked to locked condition becomes excessively high
Solution Approach 1:
The patent divides the contact interaction into two separate contact points: the first contact point between the pawl and hook for maintaining locked condition, and the second contact point between the cam and hook for reducing operating load. This segmentation allows each contact point to serve a distinct function, resolving the contradiction between maintaining engagement force and reducing operating load
Solution Approach 2:
The patent applies different local qualities to different contact points: the first contact point (pawl-hook) is designed with specific geometric relationships to maintain locking force, while the second contact point (cam-hook) is positioned to minimize the pressing force during operation. The cam is designed with a deformation promoting portion that has different mechanical properties to facilitate controlled deformation
2Ease of operation
If the spring forces are reduced to decrease the operating load, then the ease of operation is improved, but the engagement force between the lock mechanism and the striker becomes insufficient
Solution Approach 1:
By separating the functions into two contact points, the system can reduce the spring forces at the second contact point (cam-hook) to minimize operating load, while the first contact point (pawl-hook) maintains sufficient engagement force through its own geometric and force relationships
Solution Approach 2:
The cam acts as an intermediary element that mediates between the spring forces and the hook. The cam's deformation promoting portion allows controlled deformation to reduce the transmission of excessive forces to the hook, enabling reduced spring forces while maintaining adequate engagement
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
This configuration reduces the operating load required to shift from the unlocked to the locked condition without compromising the engagement force, ensuring effective locking and preventing unnecessary deformation of critical components.
Implementation Method 1
a lock spring provided between the hook and the pawl, the lock spring imparting a biasing force to the hook so as to bias the hook in a direction that the unlocked condition is formed
Implementation Method 2
a push spring provided between the cam and the base plate, the push spring biasing the cam so as to press the hook
Implementation Method 3
the cam includes a deformation promoting portion. The deformation promoting portion is set such that when the load in a direction that the striker in the locked condition is disengaged from the recess of the base plate reaches a predetermined value or more, the load may promote deformation along a direction that a length between a rotation center of the cam and a pressing portion in which the cam presses the hook is reduced
Data Source
AI summary
A lock device that includes a lock mechanism provided on one of two members to be engaged with each other, and a striker provided on the other of the two members. The lock mechanism may include a first contact point in which a pawl contacts a hook in the unlocked condition by an elastic force of a lock spring and a second contact point in which a cam contacts the hook in the unlocked condition by an elastic force of a push spring. The hook, the pawl and the cam are arranged and constructed such that these contact points are separately set at different positions. Further, the second contact point is in a certain position.