Spring-Loaded Locking Pin with Constriction for Secure Retention
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Solution Overview
Problem
Existing locking pin arrangements in machines like gas turbines and steam turbines face issues with the locking pin falling out uncontrollably, leading to access and maintenance challenges, delays, and increased costs due to the complexity of assembly and sealing problems with known solutions.
Innovation Solution
A locking pin arrangement featuring a spring-loaded locking pin with an outer thread and constriction, combined with a cylindrical bushing for axial guidance, prevents the pin from falling by allowing it to be freely movable and securely locked within a borehole, using an inner thread for assembly, ensuring the pin remains in place without external support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a locking pin is pushed towards the opening of the borehole by a spring, then the locking pin can be easily assembled and disassembled, but the locking pin may fall out uncontrollably when not in use
Solution Approach 1:
A retaining element is introduced as an intermediary component between the locking pin and the borehole. This retaining element extends into the borehole and engages with the locking pin to prevent it from falling out, while not interfering with the spring-loaded operation. The retaining element acts as a mediator that provides retention without compromising ease of operation.
Solution Approach 2:
The retention function is separated from the locking pin itself and implemented as a distinct retaining element. This segmentation allows the locking pin to maintain its spring-loaded design for easy operation, while the separate retaining element provides the necessary retention function. The locking mechanism and retention mechanism are divided into independent components.
2Reliability
If bayonet locks, locking wires or external locks are used to prevent locking pin from falling out, then the locking pin retention is improved, but the device complexity increases and sealing problems occur
Solution Approach 1:
The retaining element is integrated with the existing borehole structure rather than being a separate external component. The retaining element is formed as part of the borehole or the locking pin assembly, merging the retention function with the existing structure. This eliminates the need for separate bayonet locks or locking wires, reducing overall device complexity while maintaining retention reliability.
3Reliability
If external locks are used to secure the locking pin, then the locking pin retention is improved, but sealing problems arise in the locking arrangement
Solution Approach 1:
The retaining element serves as an intermediary that provides retention internally within the borehole structure, eliminating the need for external locks that would compromise sealing. By placing the retention mechanism inside the sealed environment rather than outside, the harmful sealing problems are avoided while still achieving reliable retention.
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 effectively prevents the locking pin from falling out, simplifies assembly and maintenance, and reduces downtime and costs by ensuring secure positioning within the borehole, even in hard-to-reach areas of turbo machines.
Implementation Method 1
The locking pin is pushed towards the opening of the borehole by a spring positioned between a first end of the locking pin and a bearing surface
Data Source
Figure 1
AI summary
Subject matter of the disclosure is a locking pin arrangement (10) with a basic element (7) for receiving an insert (8) and a fall-proof locking pin (1) for fixing the insert (8) in the basic element (7). The locking pin (1) is at least partially inserted into a borehole (2) of the basic element (7) and is pushed towards an opening of the borehole (2) by a spring (3). The locking pin (1) has a guiding surface (12) for axial guidance in the borehole (2), an outer thread (4) and a constriction (11) positioned between the outer thread (4) and the guiding surface (12), wherein the diameter of the outer thread (4) is smaller than the diameter of the guiding surface (12) and the diameter of the locking pin (1) at the constriction is smaller than the diameter of the outer thread (4). Further, the arrangement comprises an inner thread (5) going from the wall of the borehole (2) into the space formed by the constriction.