Tamper Strip Heating Element Clamping
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Solution Overview
Problem
Existing road compacting devices face issues with maintenance due to frequent breakage of electric heating elements in tamper bars, leading to undesired downtimes and increased maintenance efforts.
Innovation Solution
A tamper strip with an electric heating element that uses elastic deformation for self-clamping, providing static energy storage to secure the heating element against vibrations and thermal stresses, allowing for quick replacement and reduced fastening needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heating element is mechanically fastened with screws or clips, then the heating element is securely fixed in the tamper bar, but the heating element is susceptible to breakage from vibrations and thermal stresses
Solution Approach 1:
The heating element is designed to be self-clamping through its own thermal expansion. When heated, the element expands and automatically clamps itself against the retaining wall of the recess, eliminating the need for external fasteners and reducing susceptibility to vibration-induced loosening or breakage.
Solution Approach 2:
The heating element utilizes its thermal expansion during operation to generate clamping force. The expansion causes the element to press against the retaining wall of the recess, creating a self-retaining mechanism that secures the element without additional fastening components.
2Reliability
If the heating element is tightly secured in the recess, then the heating element remains stable during operation, but replacement of defective heating elements requires disassembly and causes downtime
Solution Approach 1:
The retention mechanism transitions from a static fastened state to a dynamic self-clamping state. During insertion, the heating element can be easily placed, and during operation, thermal expansion dynamically clamps it in place. This dynamic behavior allows for easy replacement when defective, as the clamping force diminishes when cooling or disconnected.
Solution Approach 2:
The recess is pre-designed with a retaining wall and geometry that anticipates the thermal expansion of the heating element. The preliminary structural arrangement ensures that once the element is inserted and heated, it automatically secures itself without requiring additional assembly steps.
3Strength
If multiple fasteners are used to secure the heating element, then the heating element is firmly attached, but manufacturing and assembly effort increases
Solution Approach 1:
The invention extracts and eliminates the need for separate fastening components (screws, clips, or other mechanical fasteners). The heating element itself becomes the fastening mechanism through its thermal expansion, simplifying both manufacturing and assembly processes while maintaining secure attachment.
Solution Approach 2:
The function of the heating element and the fastening mechanism are merged into a single integrated solution. The heating element performs both its primary heating function and the secondary function of self-retention through thermal expansion, eliminating the need for separate fastening components.
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 significantly reduces the risk of heating element breakage, minimizes maintenance efforts, and enables faster replacement, thereby reducing downtime and manufacturing costs.
Implementation Method 1
A spring accumulator which supports the heating element (12) in the direction of the percussive upward and downward movement S is provided. This spring accumulator causes clamping through elastic deformation.
Implementation Method 2
The electric heating is then located inside the tamper bar. EP 0 641 887 B1 discloses a surface finisher and tool as a tamper strip for a screed. Between a carrier part and a wearing part, the tamper strip forms a channel in which a heating element, in particular a heating element, is provided.
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The invention relates to a device for compacting road paving materials, comprising a screed board which is fastened on a road finisher and extends at a right angle to the direction of travel of the road finisher and a tamper that is mounted in front and/or behind the screed board. Said tamper has a tamper strip that can be driven to perform a striking upward and downward movement and the interior of which is equipped with an electrical heating unit in the form of a rod-shaped heating element that can be clamped into a recess of the tamper strip. The device according to the invention is characterized by a spring accumulator receiving the heating element in the direction of the striking upward and downward movement for clamping the heating element.