Gate Plate Bit Replacement Mechanism for Excavator Cutter Head
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Solution Overview
Problem
Existing bit replacement devices for excavating machines require a large rotary drive force to close the opening, which is inefficient and increases the weight and size of the device, and may compromise safety and workability.
Innovation Solution
A bit replacing device with a gate plate that turns between a communication position and a close position, using a gear rotating mechanism to close the opening, allowing for linear retraction of the replacement bit and reducing the need for a large drive force, while providing effective sealing to prevent high-pressure mud water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotary support member is turned to close the opening after bit retraction, then the opening can be closed effectively, but a large rotary drive force is required which increases device size and weight
Solution Approach 1:
The opening closing function is segmented into two independent parts: (1) linear retraction of the bit along the radial direction, and (2) rotation of the gate plate to close the opening. This segmentation allows the bit to be retracted without requiring the entire support member to rotate, thereby reducing the rotary drive force requirement while maintaining effective opening closure.
Solution Approach 2:
Instead of rotating the support member to close the opening (conventional approach), the invention inverts the approach by using a gate plate that rotates independently on the support member. The gate plate rotation closes the opening while the support member itself remains stationary, significantly reducing the rotary drive force needed.
2Reliability
If a large rotation device is provided for the rotary support member, then the opening can be closed, but the device weight and size increase
Solution Approach 1:
The closing mechanism is segmented into a stationary support member and a rotating gate plate. Only the gate plate needs to rotate, not the entire support member structure. This segmentation allows for a compact, lightweight rotation device that only needs to move the gate plate, rather than the entire support member assembly.
Solution Approach 2:
The rotation function is extracted from the support member and assigned to a separate gate plate component. This extraction allows the support member to remain lightweight and stationary, while the gate plate with its small rotation device handles the closing action, reducing overall device weight.
3Power
If the gate plate is used to close the opening, then the drive force is reduced, but the gate plate must be properly sealed to prevent mud water ingress
Solution Approach 1:
A flexible sealing member (rubber or elastomeric material) is provided between the gate plate and the support member. This flexible seal conforms to the mating surfaces and prevents high-pressure mud water from ingressing through the gap, while allowing the gate plate to rotate smoothly with minimal friction.
Solution Approach 2:
The sealing system uses composite construction with the gate plate (metal) mating with the support member (metal), sealed by a flexible polymer seal. This composite approach combines the structural integrity of metal components with the sealing effectiveness of elastomeric materials, preventing mud water ingress while maintaining low friction.
4Productivity
If multiple replacement bits are provided on the cutter head, then excavation efficiency is improved, but the workspace complexity increases
Solution Approach 1:
The gate plate and bit guide hole structure serve multiple functions: (1) guiding multiple replacement bits during insertion, (2) providing a common closing mechanism for multiple openings, and (3) maintaining structural integrity for the entire bit replacement assembly. This multi-functionality reduces overall device complexity despite handling multiple bits.
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 solution reduces the drive force required for closing the opening, minimizes the device's weight and size, enhances safety by keeping the gate plate hidden, and improves workability by allowing easy installation of a jig for bit replacement, while effectively preventing mud water ingress and reducing frictional resistance.
Implementation Method 1
a gate plate placed between the front surface plate and the bit guide body so as to turn about an opening/closing axial center vertical to the front surface plate
Implementation Method 2
gate sealing materials are provided between the gate plate and the front surface plate and between the gate plate and the bit guide body
Implementation Method 3
a bit sealing material for cut off is provided in a gap between the replacement bit and the bit guide hole
Implementation Method 4
the gate opening/closing device includes a gear rotating mechanism having an external gear formed on the outer periphery of the gate plate in the circumferential direction centered about the opening/closing axial center and a pinion engaged with the external gear
Data Source
AI summary
An opening for a replacement bit can be closed without a large drive force, the replacement bit can be replaced without being moved, and the workability of replacement is not impaired. A rear surface frame (29) forms a workspace (28) on the rear surface side of a spoke front surface plate (21), and openings (33) are formed on the spoke front surface plate (21) such that a replacement bit (31) can be inserted into and removed from the opening (33). A bit guide body (37) having a bit guide hole (38) is provided on the rear surface side of the opening (33). A gate plate (34) is provided which has valve ports (35) capable of communicating and closing the openings (33) and the bit guide holes (38). A gate opening/closing device (36) is provided which can turn the gate plate (34) to open or close the openings (33).