Cable Shovel Bucket Door Hinge Axis Forward Positioning
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Solution Overview
Problem
Cable shovel bucket doors experience stress, twisting, bending, and torsional loading due to uneven loads, leading to damage and inefficiencies in operation, with existing solutions increasing weight and requiring extensive maintenance.
Innovation Solution
The bucket door is pivotally secured with a hinge axis positioned forward of the exterior surface of the back wall, closer to the door's center of gravity, reducing the moment arm and allowing for a lighter, less braced door with a smaller lock or brake, and potentially using a hydraulic circuit or rod brake for restraint, eliminating the need for snubbers and bumpers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the door is reinforced with supports to strengthen it and minimize twisting and bending, then the door strength and stiffness are improved, but the weight of the bucket increases
Solution Approach 1:
The patent changes the location parameter of the hinge axis from the conventional position (on or behind the back wall exterior surface) to a forward position (in front of the back wall exterior surface). This parameter change fundamentally alters the door's structural requirements, allowing the door to be lighter while maintaining sufficient strength to handle off-center loads without excessive twisting or bending.
2Strength
If the door is made heavier with more supports, then the door can resist off-center loading better, but the productivity decreases due to slower cycle time
Solution Approach 1:
By repositioning the hinge axis forward, the patent creates a more favorable moment arm geometry that reduces the door's tendency to twist and bend under off-center loads. This allows for a lighter door construction that doesn't compromise load resistance, thereby reducing the time needed for each digging cycle and improving overall productivity.
3Reliability
If the bucket is raised higher to avoid door contact with the truck, then door damage is prevented, but the dumping distance increases and productivity decreases
Solution Approach 1:
The forward repositioning of the hinge axis creates a shallower door swing arc, which reduces the likelihood of the door contacting the truck body during dumping. This allows operators to dump loads closer to the truck without risking door damage, thereby improving dumping efficiency and productivity while maintaining door durability.
4Object-affected harmful factors
If snubbers, brakes, or hydraulic circuits are added to control door swing, then door swing damage is reduced, but the device complexity and maintenance requirements increase
Solution Approach 1:
By changing the hinge axis location parameter to a forward position, the patent inherently reduces the door swing's force and arc, eliminating or minimizing the need for additional restraint devices such as snubbers, brakes, or hydraulic circuits. This simplifies the overall system, reduces complexity, and decreases maintenance requirements while still protecting against door swing damage.
5Weight of moving object
If the hinge axis is positioned closer to the center of gravity of the door, then the moment arm is reduced and door weight can be decreased, but the door swing becomes shallower
Solution Approach 1:
The patent optimizes the hinge axis position parameter by placing it forward of the back wall exterior surface, which strategically reduces the moment arm and allows for a lighter door construction. The shallower swing resulting from this configuration is actually beneficial, as it reduces the risk of door contact with the truck and lowers the kinetic energy involved in the swing, thereby reducing the need for complex restraint systems.
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 configuration results in a shallower, less forceful door swing, reducing the risk of damage and increasing productivity by allowing closer truck dumping and minimizing cycle time, while also reducing weight and maintenance needs.
Implementation Method 1
The door is pivotally secured to move about a hinge axis positioned forward of the back wall along a distance between the back wall and a center of gravity of the loaded door
Data Source
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AI summary
A bucket for use with a cable shovel includes a shell and a door collectively defining a cavity for gathering material to be excavated. The door is pivotally secured about a pivot axis on the shell so that the door can pivot between a closed position for gathering the material and an open position for dumping the material. The pivot axis is positioned forward of an exterior surface of a back wall of the shell to create a shallower and less forceful door swing during dumping. The door has a front portion that is bent towards a digging edge on the shell so that the door has greater strength, improves bucket loading, and moves a portion of the shell away from the highest wear area.