Twin-Screw Extruder Safety Coupling With End-Face Shear Pins
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing safety clutches for twin-screw extruders face challenges such as axial offset and the need for balancing shafts, leading to increased costs and space requirements, and existing solutions either have complex intermediate shafts or uncertain torque calculation due to multiaxial stress states.
Innovation Solution
A safety coupling design featuring flangeless, cylindrical half-coupling elements with shearing elements arranged in the end faces, allowing for a slim design without axial offset, enabling two clutches to be arranged directly next to each other, with precise loading of shear pins in a parting plane and symmetrical loading for precise torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If shear pin elements are positioned on the outer circumference of coupling half-elements, then the safety coupling can transmit drive torque, but the increased space requirements prevent arrangement of two couplings side by side without axial offset
Solution Approach 1:
The shear pin elements are repositioned from a radial arrangement on the outer circumference to an axial arrangement in the end faces of the coupling half-elements. This dimensional change allows the couplings to be arranged side by side without axial offset, as the shear pins no longer project radially outward and occupy space in the coupling arrangement plane.
Solution Approach 2:
Instead of arranging shear pins radially outward from the center, the invention inverts the arrangement by placing them in the end faces, effectively reversing the conventional positioning approach. This inversion resolves the space conflict while maintaining torque transmission capability through the cylindrical walls.
2Adaptability or versatility
If intermediate shafts are used to compensate for axial offset, then the couplings can be arranged with different shaft lengths, but the device complexity and cost increase
Solution Approach 1:
The invention extracts and eliminates the intermediate shafts from the system by enabling direct side-by-side coupling arrangement. The shear pin elements positioned in the end faces allow couplings to be mounted adjacently without requiring intermediate shafts to compensate for length differences, thereby simplifying the overall drive train configuration.
3Area of stationary object
If shear elements are arranged in the end faces of coupling half-elements, then two safety couplings can be arranged directly next to each other without axial offset, but the torque transmission path becomes more complex
Solution Approach 1:
The cylindrical walls of the coupling half-elements serve dual functions: they provide the structural housing for the coupling and simultaneously act as the torque transmission path. The shear pin elements transfer torque directly through these cylindrical walls to the drive shaft, eliminating the need for separate torque transmission components and simplifying the overall structure despite the compact arrangement.
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 design achieves a virtually backlash-free connection with precise torque calculation and reduced complexity, eliminating the need for balancing shafts and allowing for efficient transmission of high torques without axial offset, thereby enhancing the safety and efficiency of the twin-screw extruder operation.
Implementation Method 1
the shear stress per shear pin can be accurately calculated... All shear elements, of which at least two are provided according to the invention, are thus subjected to precisely simultaneous and identical loads
Data Source
Figure 1
Figure 2
AI summary
A safety coupling (100) for a twin-screw extruder comprises at least one pair of coupling half-elements (10, 20), each of which has a shaft receiving bushing (21) for the shaft end (202, 301) of a drive shaft (201) or an extruder screw (301) and which can be coupled to one another via at least two shear elements (30). The coupling half-elements (10, 20) each have a flangeless, cylindrical shell (12, 22) that encloses the shaft receiving bushing (21) and transitions into a bottom section (13, 23). At least one bore (14, 24) per shear element (30) is provided on an end face that closes off the bottom section (13, 23). The coupling half-elements (10, 20) lie with their end faces (15, 25) located at the respective end of the bottom area (13, 23) in front of each other and are coupled via the shear elements (30) bridging the separating plane (T).