Lever Switching Mechanism for Small-Angle Spring Biasing
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Solution Overview
Problem
Existing lever devices face challenges in exerting sufficient biasing force when the rotation angle of the movable body is small, limiting the rotation angle of the lever and reducing the effectiveness of the tension spring's force.
Innovation Solution
A lever device with a switching mechanism that includes a rotational member and a link, allowing the tension spring's biasing force direction to switch between pulling down and pulling up the lever, even when the rotation angle is limited, by using a first and second engagement portion that move relative to the spring hook portions as the lever rotates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the rotation angle of the movable body is small, then the device can be compact and adaptable to limited installation spaces, but the rotation angle of the lever cannot be made large and it is difficult to sufficiently exert the biasing force of the tension spring on the lever
Solution Approach 1:
The switching mechanism dynamically changes the connection state between the tension spring and the lever based on the lever's position. The rotational member rotates together with the lever, and through the link mechanism, the tension spring's connection point moves from a first position to a second position, allowing the spring's biasing force to be effectively applied even when the lever's rotation angle is small.
Solution Approach 2:
The invention changes the geometric parameters of the spring connection system. By switching the connection position of the tension spring between a first spring hook portion and a second spring hook portion, the effective lever arm and force transmission characteristics are altered, enabling sufficient biasing force to be exerted on the lever despite limited rotation angles.
2Force
If a switching mechanism is added to change the direction of biasing force, then the tension spring can effectively bias the lever in both pushed-down and pulled-up positions, but the device complexity increases
Solution Approach 1:
The switching mechanism is integrated with the lever assembly. The rotational member is connected to the lever and rotates together with it, while the link connects the rotational member to the tension spring. This merging of functions allows the switching mechanism to achieve force direction change without being a completely separate system, thereby reducing overall complexity.
Solution Approach 2:
The rotational member serves multiple functions: it rotates together with the lever to sense lever position, transmits motion through the link to switch the spring connection, and provides the mounting point for the tension spring. This multi-functionality reduces the number of separate components needed for the switching 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
The lever device effectively exerts the tension spring's force on the lever, even with a small rotation angle, ensuring the biasing force is maintained and operational effectiveness is enhanced.
Implementation Method 1
a tension spring (47) to bias the lever (30)
Implementation Method 2
the link (76) is positioned such that the first engagement portion (75) and the second engagement portion (81) engage with each other and such that, as the first engagement portion (75) is moved by rotation of the rotational member (69) about the second support shaft (72), the second engagement portion (81) moves and rotates about the third support shaft (77) to move the second spring hook portion (80) to a side to which the first spring hook portion (74) moves
Data Source
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AI summary
Provided is a lever device (27) in which the biasing force of a tension spring (47) can be exerted on a lever (30) even when the angle of rotation of a movable body (32) is small. A lever device (27) includes a switching mechanism (33) to switch a direction of a biasing force of a tension spring acting on a lever rotatably supported by a movable body via a second support shaft (72) and operated to rotate the movable body. The switching mechanism includes a rotational member (69) to rotate together with the lever, the rotational member (69) including a first spring hook portion (74) and a first engagement portion (75) positioned such that an axis of the second support shaft is located between the first spring hook portion (74) and the first engagement portion (75), and a link (76) rotatably supported by the movable body via a third support shaft (77), the link (76) including a second spring hook portion (80) and a second engagement portion (81) positioned such that an axis of the third support shaft is located between the second spring hook portion (80) and the second engagement portion (81). The link is positioned such that the first engagement portion and the second engagement portion engage with each other and such that, as the first engagement portion is moved by rotation of the rotational member about the second support shaft, the second engagement portion moves and rotates about the third support shaft to move the second spring hook portion to a side to which the first spring hook portion moves.