Drum Brake Park Lever Layout to Prevent Segment Tilting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing drum brake design experiences reduced braking intensity and risk of segment dislocation due to high forces exerted by the parking brake lever, causing the first segment to tilt and lose contact with the piston, leading to incomplete braking.
Innovation Solution
The parking brake lever is modified with a thrust portion offset to the median plane, ensuring that forces are applied in the median plane, preventing the segment from tilting and increasing the braking force without altering the brake's dimensions or manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the parking brake lever applies high forces to move the segments apart, then the parking brake can effectively press the segments against the drum, but the first segment tilts and lifts from its supports, reducing braking intensity and risking complete dislocation
Solution Approach 1:
The invention moves the lever thrust application point from a single-point contact to a distributed contact area located in the median plane of the brake. By positioning the thrust portion at the median plane (halfway up the segment thickness), the force application is shifted to a different spatial dimension that eliminates the tilting moment while maintaining effective force transmission to separate the segments.
2Device complexity
If the lever thrust is applied at the current position, then the structure is simple, but the segment tilts under high forces reducing contact surface and braking intensity
Solution Approach 1:
The invention modifies only the local region where the lever contacts the segment by providing a thrust portion at the median plane, while the rest of the segment and lever structure remains unchanged. This localized modification at the contact interface is sufficient to prevent tilting under high braking forces without requiring redesign of the entire lever 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
This configuration significantly enhances the admissible braking force without risking segment tilting, allowing for increased braking performance within existing brake dimensions at minimal additional cost.
Implementation Method 1
These two segments 3, 4 are movable radially so as to be able to be pressed against the cylindrical internal face of a drum not shown so as to generate a braking torque
Implementation Method 2
They are returned towards each other by two return springs 8 and 9
Implementation Method 3
It comprises a cylindrical hydraulic chamber closed at its ends by two pistons which move away from each other when the hydraulic pressure increases
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
The invention relates to a drum brake (26) comprising a plate (27) provided with a wheel cylinder (31) and a stop (32) bearing a first segment and a second segment (28, 29), each segment (28, 29) including a web (38) having one end (41) bearing on the wheel cylinder (31) and another end (42) bearing on the stop (32), said webs extending in the same mid-plane (PM). The first segment (28) is provided with a parking brake lever (46) having one end rotationally connected to the first end (41) of the web (38) and another end provided with an actuation attachment. In addition, a connecting rod (43) is provided, comprising a first end (44) bearing on the lever (46) and a second end (45) bearing on the second segment (29). The lever (46) comprises a jog and as a result the portion of the lever that pushes against the connecting rod (43) is located in the mid-plane (PM).