Clamshell Bucket Shutter Mechanism for Trench Excavation
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Solution Overview
Problem
Clamshell buckets with open geometry have a higher vertical displacement speed but a reduced excavation volume due to soil escaping through openings, while those with closed geometry have a lower speed and greater volume but are prone to piston effects and trench collapse.
Innovation Solution
A clamshell bucket with a shutter mechanism that allows for variable geometry, enabling open geometry during descent for mud flow and closing to retain soil, thereby increasing excavation volume and reducing the number of ascents and descents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If open geometry buckets are used, then vertical displacement speed is improved, but excavation volume deteriorates
Solution Approach 1:
The bucket geometry is made dynamic through the shutter mechanism that can switch between open and closed positions. During descent, the shutter is open to allow mud flow and achieve high displacement speed. During excavation and ascent, the shutter closes to retain soil and maximize excavation volume. This dynamic transformation resolves the contradiction by adapting the bucket geometry to different operational phases.
Solution Approach 2:
The effective volume parameter of the bucket is changed dynamically through the shutter position. When the shutter is open, the effective volume is reduced to allow mud circulation. When closed, the effective volume is maximized to retain excavated soil. This parameter change enables the bucket to optimize both speed and volume capacity at different times in the operational cycle.
2Quantity of substance
If closed geometry buckets are used, then excavation volume is improved, but vertical displacement speed deteriorates
Solution Approach 1:
The bucket transitions from a static closed geometry to a dynamic configuration with movable shutters. This allows the bucket to switch between closed geometry (for volume) and open geometry (for speed) based on operational requirements, resolving the speed-volume tradeoff.
3Object-generated harmful factors
If open geometry buckets are used, then piston effect is reduced, but excavation volume deteriorates
Solution Approach 1:
The bucket back is segmented into multiple sections with individual shutters that can be independently controlled. This segmentation allows selective opening/closing of different regions to manage mud flow and reduce piston effect while maintaining excavation volume capacity.
Solution Approach 2:
The shutters dynamically adjust the opening geometry during different phases of operation, allowing mud to pass during descent (reducing piston effect) while retaining soil during ascent (maintaining volume).
Data Source
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AI summary
The grapple (10) has buckets (16, 18), each comprising sidewalls extending perpendicularly on both sides of back with concave geometry, where the back is provided with openings (38, 40). The buckets have shutters (42, 44) occupying an opening position in which the openings are formed and a closed position in which the openings are closed by the shutters. Moving units formed of an arm (28), curved oblong orifice (78) and a pin (88) act on the shutter for moving the shutters between the open position and the closed position. The shutters are fixed to the buckets in a pivoting manner. An independent claim is also included for a method for digging a trench in soil by using a grapple.