Reaming Tool Insert Securing Means for Reverse Force Resistance
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Solution Overview
Problem
Existing reaming tools often experience issues where cutting inserts become dislodged due to reverse forces during tool extraction, leading to inefficiencies and potential damage, as the clamping members, typically screws, lack sufficient bending strength to withstand these forces, especially in tools with moderate diameters and small components.
Innovation Solution
Incorporating securing means, such as a male-like stop lug and female-like countersink, in the interface between the cutting insert and its seat, which remain inactive during normal operation but engage to prevent displacement when reverse forces are applied, thereby alleviating pressure on the clamping member and ensuring the cutting insert remains securely positioned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a screw or clamp/wedge clamping member is used to hold the cutting insert fixed in the seat, then the cutting insert is held pressed against the axial and tangential support surfaces during normal operation, but the clamping member has poor bending strength and yields to reversed forces during tool extraction
Solution Approach 1:
The clamping function is segmented into two independent systems: the original clamping member (screw or clamp) that provides axial clamping force during normal operation, and a new securing means (protrusion-recess mechanism) that specifically handles reversed forces during extraction. This segmentation allows each system to be optimized for its specific function without compromise.
Solution Approach 2:
The securing means with protrusion and recess is designed to activate in advance during tool extraction to counteract reversed forces before they can dislodge the cutting insert. The protrusion engages with the recess to create a mechanical stop that prevents the cutting insert from moving against the reversed force direction.
2Ease of operation
If the tool is retracted from the tube blank during machining interruptions, then the cutting inserts are subjected to reverse forces that tend to dislodge them from their seats, but the clamping member cannot withstand these reversed forces
Solution Approach 1:
The securing means is pre-configured in the cutting insert and seat structure before tool extraction occurs. The protrusion and recess are positioned and dimensioned in advance to engage automatically when reversed forces are applied during tool retraction, preventing dislodgement without requiring any additional action during the extraction process.
Solution Approach 2:
The protrusion and recess forming the securing means act as an intermediary mechanical element between the cutting insert and the seat. This intermediary structure mediates the interaction between the cutting insert and reversed forces during tool extraction, providing a reliable connection that neither the original clamping member alone could provide.
3Device complexity
If the cutting insert is small and the tool has moderate diameter, then the clamping member is relatively small and lacks sufficient bending strength, but the reversed forces during extraction are still significant
Solution Approach 1:
The load-bearing function is segmented between the original clamping member (handling axial clamping) and the securing means with protrusion and recess (handling reversed forces). This allows the clamping member to remain small and simple while the securing means provides the additional strength needed for extraction scenarios.
Solution Approach 2:
The solution creates a composite clamping system combining two different mechanical mechanisms: the threaded or clamp-based original clamping member and the geometric interlocking protrusion-recess securing means. This composite approach provides both the fine adjustment capability of the original system and the high strength of the geometric interlock.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A reaming tool including a head (2) and a detachable cutting insert that is fixed in a seat (17) in the head. The seat includes a radial support surface (18), a tangential support surface (19), and an axial support surface (20), while the cutting insert has the shape of a mirror-symmetrical polyhedron comprising six limiting surfaces (28, 32), viz. two chip surfaces (28) and at least two clearance surfaces (32), a number of alternately usable, identical cutting edges (34) being formed in transitions between the chip and clearance surfaces. According to the invention, in at least one of the three limiting surfaces of the cutting insert, there is formed a female- or male-like securing means (38) that co-operates with a complementary, male- or female-like securing means (37) in the seat (17), more precisely in an inactive, contactless state as long as the cutting insert is held pressed by the cutting forces against the axial support surface (20) of the seat, the securing means being potentially activatable by being brought into contact with each other in case the cutting insert would unintentionally be distanced from the axial support surface (20) against the action of a clamping member (25). In addition, the invention relates to a tool head and a reaming insert for the present tool.