Sanding Machine Pneumatic Thrust Control
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Solution Overview
Problem
Existing sanding machines for wood and metal panels require high pneumatic force to move thrust elements due to the need to overcome the sum of pneumatic force and friction force generated by gaskets, which can compromise the sanding process.
Innovation Solution
The sanding machine employs actuator cylinders with a pressure differential between two pneumatic circuits, using a solenoid valve to control the movement of thrust elements, allowing for a lower pneumatic force to be used when moving elements to their lowered operating position, thereby reducing friction and pneumatic force required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lower chamber is continuously connected to the second pneumatic circuit, then the thrust element can be reliably returned to the raised rest position, but the pneumatic force required to move the thrust element to the lowered operating position becomes excessively high
Solution Approach 1:
The pneumatic control is segmented into two independent circuits: the first pneumatic circuit (32) continuously supplies compressed air to the lower chamber (31) to maintain return force, while the second pneumatic circuit (33) is selectively activated via solenoid valve (37) to supply additional force only when lowering the thrust element is required. This segmentation allows reliable return positioning without requiring excessively high continuous pneumatic force.
Solution Approach 2:
The second pneumatic circuit operates periodically rather than continuously - it is activated only during the brief period when the solenoid valve closes and the thrust element needs to be lowered. This periodic activation reduces the average pneumatic force requirement while maintaining the ability to overcome friction and move the thrust element when needed.
2Reliability
If three annular gaskets are mounted on the output rod to separate chambers, then fluid-tight separation is achieved, but friction force increases significantly
Solution Approach 1:
The third annular gasket (36) that was originally intended to separate the lower chamber from the outside is extracted/removed from the design. The patent recognizes that this gasket creates unnecessary friction without providing sufficient additional sealing benefit, since the first two gaskets already provide adequate fluid-tight separation between the upper and lower chambers. This reduction in gasket quantity directly reduces friction force on the output rod.
3Ease of operation
If the first pneumatic circuit must generate force equal to the sum of second circuit force and friction force, then the thrust element can be moved to the lowered position, but the sanding process is compromised due to excessive force on panels
Solution Approach 1:
The pneumatic force generation is segmented between two circuits with different functions: the first circuit (32) provides baseline force for normal operation, while the second circuit (33) provides supplemental force only when needed for positioning. This segmentation allows the system to achieve the necessary force for moving thrust elements without requiring the first circuit to continuously generate excessively high forces that would harm the sanding process.
Solution Approach 2:
The solenoid valve (37) acts as an intermediary that controls the selective activation of the second pneumatic circuit. It mediates between the need for high force (when lowering the thrust element) and the need to minimize force (during sanding operation), allowing the system to switch between force modes as needed without compromising manufacturing precision.
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 approach reduces the pneumatic force exerted on panels, improving the sanding process by minimizing the impact of friction and pneumatic pressure, resulting in more precise and effective sanding/finishing of panels.
Implementation Method 1
The first annular gasket is a lip gasket designed to expand radially under the thrust of the first pneumatic circuit
Implementation Method 2
the second annular gasket is a lip gasket designed to expand radially under the thrust of the second pneumatic circuit
Implementation Method 3
each thrust element is normally arranged in its raised rest position, and is selectively moved to its lowered operating position following the activation of the relative power supply solenoid valve
Data Source
AI summary
In a sanding machine for sanding/finishing panels made of wood, metal or the like, an abrasive belt is moved so as to cause it to come into contact with a panel by a plurality of thrust elements, which are distributed inside the abrasive belt, and are moved perpendicularly to the panel by respective actuator cylinders, each of which has an output rod which is moveable between a lowered operating position and a raised rest position under the thrust of a pressurised gas supplied in a continuous manner to an upper chamber of the actuator cylinder and in a selective manner to a lower chamber of the actuator cylinder itself.