Articulated Lever Actuation Brake With Roller-Cam Wear Reduction
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Solution Overview
Problem
Existing actuation units in the field of sheet metal working, particularly for motor vehicle body construction, face issues with wear due to friction in braking units and require larger radial dimensions as cylinder size increases, lacking the ability to exclude or automatically recover the braking unit during installation or pressure drops.
Innovation Solution
A compact braking unit with a threaded shaft and a head portion featuring a cone frustum surface, interacting with rollers that assume radial configurations for enhanced friction and minimal radial dimensions, allowing for effective braking and easy deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If disc brake with elastic elements is used to brake the rotation of the shaft, then reliable braking action is achieved, but strong wear occurs due to friction between circular or disc surfaces
Solution Approach 1:
The patent replaces the traditional disc brake mechanical system with a cam-based braking mechanism. The cam profile is designed to engage with a follower, converting rotational motion into controlled linear motion that activates the brake. This substitution eliminates the continuous friction contact of disc brakes while maintaining reliable braking action through intermittent mechanical engagement.
Solution Approach 2:
The patent changes the geometric parameters of the braking surfaces from circular or disc shapes to cam profile geometries. The cam profile parameters (radius, eccentricity, angle of contact) are optimized to provide effective braking while minimizing the contact area and duration of friction, thereby reducing wear.
2Reliability
If larger diameter braking elements are used to achieve effective braking action, then braking effectiveness is improved, but radial overall dimensions of the actuation unit increase
Solution Approach 1:
The patent transitions from a radial braking arrangement to an axial braking arrangement. Instead of expanding the braking elements radially, the cam mechanism utilizes axial displacement to activate the brake. The cam profile converts radial rotational motion into axial linear motion, allowing effective braking within compact radial dimensions.
Solution Approach 2:
The patent employs curved cam surfaces with optimized radii of curvature to achieve effective braking action. The cam profile geometry, rather than large diameter disc surfaces, provides the necessary mechanical advantage and contact pressure for reliable braking while maintaining compact overall dimensions.
3Reliability
If braking unit is activated automatically in event of insufficient pressure, then safety is improved, but ability to exclude or manually control braking is reduced
Solution Approach 1:
The patent implements a dynamic braking system where the cam mechanism can switch between automatic activation mode and manual control mode. The cam profile is designed to respond to pressure changes automatically, but also allows for manual override or deactivation through a control mechanism that adjusts the cam-follower engagement, providing both safety and operational flexibility.
Solution Approach 2:
The braking unit is designed with multi-functionality, serving both as an automatic safety device activated by pressure monitoring and as a manually controllable brake. The cam mechanism can operate in different modes depending on the control input, allowing the same hardware to provide both automatic protection and manual operational control.
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 provides a reliable and low-wear braking action with reduced radial dimensions, enabling efficient braking and easy manual deactivation, addressing the limitations of existing braking units in terms of size and operational flexibility.
Implementation Method 1
a threaded shaft (41) comprising a first end operatively coupled to the stem (21) of the pneumatic cylinder in such a way that a translation of the stem determines a rotation of the threaded shaft
Implementation Method 2
a braking assembly locked against rotation and axially movable relative to the head portion of the threaded shaft between a first non-braking configuration in which the braking assembly is not in contact with the at least one surface portion of the head portion and a second braking configuration in which the braking assembly is in contact with the at least one surface portion of the head portion
Data Source
AI summary
An actuation unit includes an actuating arm pivotable between an open and closed position; a pneumatic cylinder comprising a stem movable linearly along a cylinder axis and configured to control pivoting of the actuating arm; and a closing device that includes a braking unit configured to brake movement of the actuating arm having a surface portion configured to come into contact with at least one braking assembly. The braking assembly is locked against rotation and axially movable between a non-braking and braking configuration. The surface portion is in a non-orthogonal arrangement with respect to the cylinder axis and the braking assembly includes a plurality of rollers retained in the braking assembly with clearance at least with respect to a radial movement thereof, the rollers being able to assume a first radial configuration not in contact with the surface portion and a second radial configuration in contact with the surface portion.