Nozzle Dead Man Control Lever for Safer Abrasive Blasting
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Solution Overview
Problem
Existing abrasive blasting apparatuses pose safety risks due to unpredictable movement and potential injury from the nozzle and abrasive expulsion, necessitating an improved dead man control arrangement.
Innovation Solution
A dead man control arrangement with a manually operable control part that moves between operating and non-operating positions, generating control signals for apparatus operation only upon receipt of a signal, and includes a selector for additional operations, ensuring safe and controlled abrasive blasting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dead man control arrangement is implemented to prevent accidental activation, then safety is improved, but device complexity increases
Solution Approach 1:
The dead man control arrangement is segmented into distinct functional components: a manually operable control part (trigger assembly), a control signal governor (valve body with internal passages), and remote controllers (at the compressor and blast pot). This segmentation allows each component to perform its specific function independently, simplifying the overall design while maintaining safety. The trigger assembly generates control signals that are transmitted through the hose to remote locations, eliminating the need for a single complex control mechanism.
Solution Approach 2:
Compressed air serves as an intermediary medium to transmit control signals from the manually operable trigger assembly to the remote controllers. When the user pulls the trigger, it opens a valve that allows compressed air to flow through specific passages to the remote valve arrangements, which then activate the blasting apparatus. This intermediary approach simplifies the control mechanism by using pneumatic signaling rather than direct mechanical or electrical connections.
2Reliability
If continuous user input is required for operation, then safety is improved, but ease of operation deteriorates
Solution Approach 1:
The dead man control arrangement is designed to be self-service in terms of safety monitoring. The system automatically detects when the trigger is released and immediately shuts off the blasting apparatus without requiring additional user actions. The compressed air system continuously monitors the trigger state, and when the trigger returns to its resting position, the control signals are automatically revoked, causing the remote valves to close and stop the abrasive flow. This automatic response maintains safety while minimizing the user's operational burden.
3Reliability
If control signals are sent to multiple remote controllers, then reliability is improved, but device complexity increases
Solution Approach 1:
The compressed air system serves multiple functions: it powers the blasting apparatus, transmits control signals from the trigger, and provides the medium for signal transmission to multiple remote controllers. The same compressed air lines that supply power to the blast pot and compressor also carry the control signals generated by the trigger assembly. This multi-functionality reduces the need for separate control wiring or signaling systems, simplifying the overall control architecture while ensuring reliable operation across multiple components.
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
The improved dead man control arrangement enhances safety by requiring continuous user input for apparatus operation, preventing accidental activation and reducing the risk of injury during abrasive blasting.
Implementation Method 1
a control lever rotatable about a nozzle holder, and having an elongate handle part providing a slot therein, the slot having a length direction extending in a longitudinal direction of the handle part and having a width sufficient for a part of the nozzle to extend through the slot when the control lever is held in the operating position; a spring biased against the control lever so as to urge the control lever towards the non-operating position
Implementation Method 2
particles of abrasive material entrained in a stream of pressurised gas are expelled from a nozzle
Implementation Method 3
particles of abrasive material entrained in a stream of pressurised gas are expelled from a nozzle so as to be forcibly directed, or blasted, onto a surface in order to clean and/or abrade the surface
Implementation Method 4
particles of abrasive material entrained in a stream of pressurised gas are expelled from a nozzle so as to be forcibly directed, or blasted, onto a surface in order to clean and/or abrade the surface
Data Source
AI summary
A nozzle arrangement for use in expelling pressurized fluid includes a dead man control. The dead man control has a manually operable control part movable between a non-operating position, which prevents operation of the nozzle arrangement, and an operating position, and biased towards the non-operating position. The manually operable control part is pivotably coupled relative to a nozzle holder of the nozzle arrangement, which extends away from the pivotal coupling substantially towards a distal end of a nozzle part of the nozzle arrangement. The manually operable control part includes a handle part which in the operating position is substantially against and aligned with the nozzle part.