Shear Bolt Obstruction Assembly for Disconnectable Joints
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Solution Overview
Problem
The installation of disconnectable electrical joints in power feeder applications is challenging due to the need for multiple bolts to be hand-tightened and torqued, often resulting in improper torque application, especially in confined spaces, and requires specialized tools or bolts to ensure proper connection.
Innovation Solution
A shear bolt with a torque head portion and an obstruction piece that prevents the joint sleeve from being applied until the bolts are properly tightened, ensuring the torque head portion shears off at a predetermined torque, allowing conventional shear bolts to be used without a torque tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hand-tightening and torque methods are used for multiple bolts, then proper connection can be achieved, but installation difficulty increases significantly in confined spaces
Solution Approach 1:
The bolt is segmented into two functional parts: a torque head portion that shears off at predetermined torque, and a main bolt portion that remains for final tightening. This segmentation allows the torque control function to be separated from the fastening function, enabling reliable torque application without requiring complex torque tools in confined spaces.
Solution Approach 2:
The obstruction piece automatically prevents sleeve application until the torque head shears off, indicating proper torque has been applied. This self-service mechanism ensures that the bolted connection achieves proper torque without requiring external verification or specialized tools, while the obstruction piece self-regulates the installation sequence.
2Reliability
If barrier head bolts with extended torque head are used to prevent premature sleeve application, then proper torque ensuring is improved, but device complexity increases due to proprietary specialized bolts
Solution Approach 1:
The obstruction function is extracted from the bolt head itself and implemented as a separate obstruction piece that can be applied to conventional shear bolts. This extraction eliminates the need for proprietary barrier head bolts while achieving the same reliability benefit of preventing premature sleeve application.
Solution Approach 2:
The obstruction piece is designed to work with conventional shear bolts, making the solution universal rather than proprietary. The obstruction piece serves multiple functions: preventing premature sleeve application, indicating when torque has been applied, and maintaining compatibility with standard bolt designs.
3Reliability
If multiple bolts require hand-tightening and torqueing in confined spaces, then proper connection can be achieved, but installation time increases
Solution Approach 1:
The torque head portion is designed to shear off at a predetermined torque level during the hand-tightening phase, performing the torque control action preliminarily before final tightening. This preliminary torque application eliminates the need for subsequent torque tool operations, accelerating installation while ensuring proper torque.
Solution Approach 2:
The shearing of the torque head portion allows the installation process to skip the time-consuming torque tool operation. By rushing through the torque application phase with the self-shearing mechanism, installation speed increases while maintaining connection reliability.
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
Ensures proper tightening of joint bolts before allowing the joint sleeve to be applied, simplifying the installation process and eliminating the need for specialized tools, thereby reducing operator error and improving connection reliability.
Implementation Method 1
a torque head portion... that prevents the joint sleeve from being applied until the bolts are properly tightened, ensuring the torque head portion shears off at a predetermined torque
Data Source
AI summary
An obstruction assembly for use in connecting a cable to a disconnectable joint is provided, wherein the connection is to be covered by a sleeve. The obstruction assembly includes a shear bolt having a torque head portion and a main bolt portion, the torque head portion designed to at least partially detach from the main bolt portion at a predetermined torque, and wherein the main bolt portion is designed to connect a cable to a disconnectable joint. The obstruction assembly also includes an obstruction piece having a projection extending away from the main bolt portion a sufficient distance so as to inhibit the placement of a sleeve on the connection between the cable and the disconnectable joint. Preferably, the obstruction piece is removable, in whole or in part, after the torque head portion is at least partially removed from the main bolt portion, such that the sleeve can be properly positioned on the joint.