Dual-Guide Lever Cam Structure for Rattle-Free Operation
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Solution Overview
Problem
The existing lever device experiences rattling when another lever is operated while the lever device is in the depressed position due to a gap between the guide pin and the cam groove.
Innovation Solution
The lever device incorporates a cam body with a cam groove and guide members that change position relative to the cam groove as the lever is pivoted, ensuring the cam body is positioned securely at two points when the lever is depressed, thereby eliminating the gap and preventing rattling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a gap is provided between the guide pin and the cam groove to enable smooth movement, then the lever can move smoothly between positions, but rattling occurs when another lever is operated while the lever is in the depressed position
Solution Approach 1:
The single cam groove is segmented into multiple groove portions (first groove portion, second groove portion, third groove portion, fourth groove portion, fifth groove portion) that accommodate the guide pin at different lever positions. This segmentation allows the guide pin to engage with specific groove portions at depressed and raised positions, reducing rattling while maintaining smooth movement through the connecting groove portions.
Solution Approach 2:
Different portions of the cam groove have different functional characteristics. The first and second groove portions provide engagement at the depressed position, the fourth and fifth groove portions provide engagement at the raised position, while the third groove portion connects them. This local differentiation allows the groove to simultaneously provide smooth movement and rattling prevention at different locations.
2Reliability
If the guide pin fits tightly in the cam groove to prevent rattling, then stability is improved, but the lever movement becomes restricted and less smooth
Solution Approach 1:
The cam groove design allows dynamic engagement between the guide pin and different groove portions during lever movement. The guide pin transitions from one groove portion to another as the lever moves between depressed and raised positions, providing both tight engagement for stability and smooth transition for ease of operation.
3Reliability
If multiple guide members are used to position the cam body at two points, then rattling is prevented, but the device complexity increases
Solution Approach 1:
The single cam groove structure serves multiple functions: it guides the guide pin during movement, provides engagement points at both depressed and raised positions, and prevents rattling through its multi-portion design. This multi-functionality reduces the need for separate guide members while achieving the same reliability benefits.
Data Source
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AI summary
Rattling that would occur when another lever (30) is operated with a lever (31) in its depressed position is prevented or reduced. A lever device (22) includes a base (25), a movable body (26) pivotally supported on the base (25) rotatably about a first lateral shaft (27), a lever (31) supported by the movable body (26) and pivotable between a depressed position and a raised position, a cam body (33) including a cam groove (34), the cam body (33) being pivotally supported on the movable body rotatably (26) about a second lateral shaft and configured to rotate about the second lateral shaft as the lever (31) is pivoted, and guide members (36) attached to the base (25) and inserted in the cam groove (34), the guide members (36) being configured to change a position thereof relative to the cam groove (34) as the lever (31) is pivoted. The guide members (36) include a first guide member (36A) and a second guide member (36B). The cam groove (34) includes a first groove portion (34a) in which the first guide member (36A) is positioned when the lever (31) is in the depressed position, and a second groove portion (36b) in which the second guide member (36B) is positioned when the lever (31) is in the depressed position.