Guide Cam Groove Locking for Silent On-Board Operation
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Solution Overview
Problem
Existing guide cam devices suffer from issues such as impact sounds due to steps in the cam groove, high processing costs, increased friction resistance, and potential malfunctions from vibrations, making them unsuitable for silent operation in on-board devices.
Innovation Solution
A guide cam device with a cam groove design that includes a first, second, and third groove, a locking recess, and a restriction member to inhibit entry to the third groove while allowing movement to the second groove, eliminating steps on the bottom surface and reducing friction, using an elastically deformable spring member as the restriction member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a step is formed on the bottom surface of the cam groove to lock the guide pin, then the guide pin can be locked in the groove, but impact sounds are generated and operation feelings deteriorate
Solution Approach 1:
The patent converts the harmful impact sound generated by the guide pin dropping into the step into a beneficial locking mechanism. The step is designed so that the guide pin intentionally drops into it to achieve reliable locking, and the spring absorbs the impact energy to prevent harmful vibrations and sounds during normal operation.
Solution Approach 2:
A spring is installed beforehand in the cam groove to cushion the impact when the guide pin drops into the locking step. The spring absorbs the shock energy, preventing harmful impact sounds and vibrations, while still allowing the guide pin to achieve reliable locking in the step.
2Reliability
If a hexagonal guide pin is used with a loop-shaped groove to achieve locking, then the guide pin can move in fixed direction, but the structure becomes complicated and processing cost increases
Solution Approach 1:
The patent extracts the hexagonal cross-section feature from the guide pin, using a simple cylindrical pin instead. The locking function is achieved through the cam groove's heart-shaped geometry and locking step, eliminating the need for complex hexagonal structures and reducing manufacturing complexity.
Solution Approach 2:
Instead of making the guide pin complex (hexagonal) to achieve locking, the patent inverts the approach by making the cam groove complex (heart-shaped with locking step) while keeping the guide pin simple (cylindrical). This reduces the complexity of the moving part while maintaining locking reliability.
3Reliability
If the guide pin slides with side surface contact in the groove, then locking can be achieved, but friction resistance increases and smooth movement becomes difficult
Solution Approach 1:
The patent uses a cylindrical guide pin with a circular cross-section that fits into the cam groove, allowing point or line contact rather than face-to-face sliding contact. This curved geometry reduces the contact area and friction resistance, enabling smooth movement while maintaining locking reliability through the heart-shaped groove design.
4Ease of operation
If the heart cam is biased by a spring to maintain upright posture, then the projection can move in fixed direction, but vibrations from external impact may cause malfunction
Solution Approach 1:
The spring biasing the heart cam is designed to provide both the necessary force for fixed-direction movement and sufficient cushioning against external impacts. The spring's elastic properties absorb vibration energy from external impacts, preventing malfunctions while maintaining the cam's upright posture and the projection's fixed-direction movement capability.
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 smooth and silent operation by eliminating impact sounds, reducing friction, and preventing malfunctions, while allowing reliable movement of the projection to a lockable position without forming steps, thus enhancing usability in on-board devices.
Implementation Method 1
the restriction member is deformed or moved to enable the projection to move to the first groove
Data Source
AI summary
A guide cam device includes a cam groove, a projection, and a restriction member. The cam groove includes: first, second, and third grooves, the second and third grooves branching forward from the first groove; and a locking recess positioned between a forward end of the second groove and a forward end of the third groove. The projection is configured to move forward and backward in the cam groove and enter a locked state upon entering the locking recess. The restriction member is configured to inhibit entry of the projection from the first groove to the third groove and permit the projection to advance from the first groove to the second groove. In response to being pushed by the projection that exits the locking recess and moves backward in the third groove, the restriction member is deformed or moved to enable the projection to move to the first groove.