Bit Holder With Pyramid Bracing For Milling Force Distribution
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Solution Overview
Problem
Existing bit holders for earth working machines, such as road milling machines, face issues with short service life due to inadequate discharge of working forces and high flexural stresses on the insertion projection, leading to potential breakage and insufficient absorption of transverse forces.
Innovation Solution
The bit holder features three stripping surfaces at angles to each other, forming a pyramid-like bracing member that optimally distributes and discharges working forces, with additional surfaces that can be added for specific tasks, and a symmetric design to handle varying force directions and transverse forces, ensuring reliable fixation and reduced load on the insertion projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two stripping surfaces are used in the bit holder, then the bit holder can be secured to the base part, but the service life is short due to insufficient force distribution and insertion projection breakage
Solution Approach 1:
The invention transitions from a two-dimensional bracing system (two stripping surfaces) to a three-dimensional bracing system (three stripping surfaces forming a pyramid-like structure). This dimensional enhancement distributes forces more effectively across multiple planes, reducing the stress concentration on the insertion projection and extending the service life of the bit holder.
2Force
If the bit holder is secured with two stripping surfaces, then it can be fixed to the base part, but transverse forces cannot be absorbed stably
Solution Approach 1:
By adding a third stripping surface to form a pyramid-like bracing structure, the system gains enhanced stability in absorbing transverse forces. The three surfaces create a more robust geometric configuration that resists forces acting in multiple directions, improving overall force absorption stability.
3Force
If the insertion projection is exposed to large flexural stresses, then the bit holder can transmit working forces, but the insertion projection breaks due to fatigue
Solution Approach 1:
The invention segments the force transmission path by introducing three stripping surfaces that distribute working forces across multiple contact points with the base part. This segmentation reduces the flexural stress concentration on the insertion projection, preventing fatigue-induced breakage while maintaining effective working force transmission.
4Ease of operation
If a clamping screw is used to maintain fixed correlation of surfaces, then the bit holder can be secured, but the insertion projection is still exposed to high stresses
Solution Approach 1:
The three-dimensional pyramid-like bracing structure formed by three stripping surfaces provides superior force distribution compared to the two-surface configuration. This geometric enhancement reduces the stress on the insertion projection while maintaining secure mounting through the clamping screw, as forces are distributed across three contact planes instead of two.
Data Source
AI summary
The invention relates to a bit holder for an earth working machine, in particular a road milling machine, that comprises a bit receptacle in the region of a working side of a support member and that indirectly or directly carries an insertion projection on an insertion projection side of the support member, the support member comprising two stripping surfaces [first or second stripping surfaces] that form a stripping surface pair and are at an angle to one another. In order to achieve a stable and long-lived configuration with such a bit holder, provision is made according to the present invention that the support member comprises at least one further stripping surface that is at an angle to the two stripping surfaces of the stripping surface pair.