Retained Shear Bolt Head Mechanism for Safe Torque Shearing
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Solution Overview
Problem
Conventional shear bolts pose a risk of accidentally dropping the sheared bolt head during installation, which can lead to damage or injury, especially in situations where mechanics wear heavy gloves and work with overhead cables.
Innovation Solution
A safety shear bolt design featuring a coupling mechanism that securely connects the sheared torque head portion to the main bolt portion, preventing free longitudinal movement and allowing rotational detachment, thereby preventing inadvertent dropping. This mechanism includes various fastening devices such as blind rivets, humpback cotter pins, or split bushings to ensure the torque head remains attached after shearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shear bolt is used with an extended torque head portion, then the bolt can be torqued to the proper value, but the sheared bolt head may accidentally drop during installation
Solution Approach 1:
A coupling mechanism acts as an intermediary between the torque head portion and main bolt portion, preventing the torque head from dropping after shearing while maintaining the torque control function. The coupling mechanism includes a retaining structure that captures the sheared torque head and prevents it from falling to the ground.
Solution Approach 2:
The bolt is segmented into distinct functional portions: a torque head portion for applying torque, a stem portion that shears at a predetermined torque value, and a main bolt portion that remains in place. The coupling mechanism further segments the connection by providing a retaining structure that holds the sheared torque head portion separately from the main bolt portion.
2Device complexity
If the torque head portion is freely connected to the main bolt portion, then the structure is simple, but the sheared head cannot be prevented from falling
Solution Approach 1:
The coupling mechanism serves as an intermediary component that adds minimal complexity while significantly improving reliability. It includes a retaining structure such as a cup-shaped element or clevis that captures the sheared torque head portion, preventing it from falling while allowing the rest of the bolt structure to remain simple.
3Object-affected harmful factors
If a coupling mechanism is added to prevent dropping, then safety is improved, but the device complexity increases
Solution Approach 1:
The coupling mechanism is designed as a relatively simple intermediary component that can be integrated into existing shear bolt designs. Examples include a cup-shaped retaining structure or a clevis with pins, which add minimal complexity compared to the overall bolt assembly while effectively preventing the torque head from dropping.
Solution Approach 2:
The coupling mechanism can be designed to nest around or within the torque head portion and main bolt portion, creating a compact integrated assembly. The retaining structure may enclose the sheared torque head portion within its cavity, providing a space-efficient solution that minimizes additional complexity.
Data Source
AI summary
A safety shear bolt includes a main bolt portion and a torque head portion connected to the main bolt portion. The torque head portion includes an extended head portion, a stem portion rigidly connecting the main bolt portion to the torque head portion, and a coupling mechanism rotatably connecting the extended head portion to the main bolt portion. The stem portion is configured to shear when a predetermined torque is applied to the extended head portion, while the coupling mechanism prevents the extended head portion from dropping after shearing off from the main bolt portion.