Excavator Rotary Tool Flange Retention Under Bearing Overload
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Solution Overview
Problem
Existing rotating devices on work machines, such as excavators, are prone to bearing failure due to overloads, leading to material damage and potential personal injury from uncontrolled attachment loss.
Innovation Solution
A safety device with redundant mechanical components, including retaining elements that engage mechanically with the flange part to redirect force flow and prevent unintentional loosening, featuring adjustable play to manage overload and incorporate a form-fitting part to secure the flange part against detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retaining elements are added to prevent unintentional loosening, then reliability is improved, but device complexity increases
Solution Approach 1:
The retaining elements are pre-positioned on the rotary drive before operation, ready to engage with the flange part if play develops. This preliminary positioning allows the safety mechanism to activate automatically when needed, without requiring additional control systems or complex actuation mechanisms during operation.
Solution Approach 2:
The retaining elements are designed as simple, replaceable mechanical components that can be easily installed and removed. Their straightforward design allows for low-cost manufacturing and replacement, making the complexity addition acceptable given the significant reliability improvement they provide.
2Reliability
If retaining elements engage to prevent loosening, then reliability is improved, but ease of operation deteriorates due to restricted rotational movement
Solution Approach 1:
The retaining elements are designed with adjustable play that allows dynamic adaptation during operation. During normal operation with adequate play, the retaining elements remain disengaged and do not restrict rotation. When play decreases below a certain level, the retaining elements automatically engage to provide security. This dynamic behavior ensures both operational freedom and safety.
Solution Approach 2:
The system changes its mechanical state based on the play parameter. When play is within acceptable ranges, the retaining elements remain inactive, allowing free rotation. When play falls below a threshold, the geometric relationship between the retaining elements and flange part changes, causing automatic engagement. This parameter-based control eliminates the need for continuous monitoring while maintaining both freedom and security.
3Reliability
If form-fitting parts are used to secure against detachment, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The form-fitting engagement is segmented into discrete geometric features on both the retaining element and flange part. Rather than requiring a complete form-fitting interface, the engagement is achieved through specific contour features that are easier to manufacture with standard tolerances. This segmentation reduces the overall precision requirement while maintaining effective security.
Data Source
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AI summary
The invention relates to a rotating apparatus for rotary positioning of a tool (16) on a boom (12) of a work machine (10), in particular of an excavator, having an attachment part (26) connected to the boom (12), a flange part (28), which is mounted on the attachment part (26) preferably so as to be rotatable without limitation and which is for attaching the tool (16), and a rotary drive (32) for rotational movement of the flange part (28). According to the invention, in order to prevent unwanted disengagement of the flange part (28), a safety device (18) which has at least one retaining element (48) which comes into engagement with the flange part (28) or a part of the rotary drive (32) when a play for the rotational movement is not reached, is provided.