Countersinking Knife Centering for Higher Lowering Accuracy
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Solution Overview
Problem
Existing pressure-controlled lowering tools face challenges in achieving high accuracy and reproducibility in the cutting process, with a maximum accuracy of +/- 0.2 mm being the best achieved so far.
Innovation Solution
The introduction of a radial-looking knife centering system within the knife housing, which includes a centering groove on the knife and a complementary centering bolt in the housing, ensures precise alignment and minimizes radial shift during the cutting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If play is provided in the bearing bore for the pivot bearing to enable smooth knife pivoting, then ease of operation is improved, but manufacturing precision deteriorates with accuracy limited to +/- 0.2 mm
Solution Approach 1:
The patent divides the knife support system into two independent functional segments: the pivot bearing (with play for smooth pivoting) and the centering mechanism (with positive engagement for precision). The centering groove and centering bolt are positioned at a distance from the pivot bearing, creating separate zones for movement and positioning functions.
Solution Approach 2:
The centering groove and centering bolt act as intermediary elements between the knife and the knife housing. These centering features mediate the relationship between the knife's pivot movement and its positional accuracy, enabling both smooth operation and high precision by providing a positive engagement interface.
2Manufacturing precision
If a rigid centering mechanism is installed to eliminate play and improve accuracy, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by providing centering features only at specific locations (centering groove on the knife base, centering bolt in the knife housing) rather than throughout the entire structure. The centering groove is positioned at a distance from the pivot bearing, creating a localized centering zone that eliminates play without requiring complex mechanisms throughout the entire knife assembly.
Solution Approach 2:
Instead of making the pivot bearing itself precise and eliminating play at the pivot point, the patent inverts the approach by providing play at the pivot bearing and compensating for it with a separate centering mechanism. This inversion allows the pivot bearing to remain simple and compliant while achieving precision through the centering groove and bolt 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 solution enables a significant improvement in lowering accuracy to +/- 0.1 mm and enhances reproducibility with minimal scatter, meeting the extended requirements of the market and improving accuracy by a factor of 10 compared to traditional tools.
Implementation Method 1
a piston (24) displaceable in a cylinder chamber (25) of the base body (2), which piston (24) is acted upon by a pressure medium (13) in order to generate a lowering force
Implementation Method 2
a compression spring (31), whose lower end (31b) bears against a stop (32) on the housing side, which compression spring (31) is pre-loaded in the direction of arrow 28
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Pressure-media controlled countersinking tool (1) with one or more chip-removing knives (7) arranged in a rotatably driven base body (2), which can be actuated in their pivot position by supplying a pressure medium (13), wherein the actuation of the at least one knife (7) is effected via at least one piston-cylinder unit (24, 25) actuated by the pressure medium (13), wherein the at least one knife (7) is pivotably mounted on a bearing pin (9) forming a pivot axis (9a) and can be pivoted out of a knife chamber (5) arranged in the knife housing (3), wherein a centering device (21, 23; 42, 43) is arranged between the knife (7) and the knife window (6) of the base body (2) at a radial distance (44, 45, 46) from the pivot axis (9a) and in the pivot range of the at least one knife (7).