Bolt Feeder Pusher Mechanism to Prevent Projection Crush
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Solution Overview
Problem
Existing bolt welding methods result in improper welding due to the crush of projections on the bolt head when the upper electrode presses the top surface, leading to unsatisfactory bonding between the bolt head and the workpiece.
Innovation Solution
A resistance welding system that uses a pusher member to push the non-projection area of the bolt head, minimizing crush and ensuring proper alignment with a guide member for reliable insertion into the lower electrode, followed by welding the bolt head to the workpiece surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the upper electrode presses the top surface of the bolt head to insert the shaft into the lower electrode, then the shaft insertion is achieved, but the projection on the top surface is crushed causing improper welding
Solution Approach 1:
A pusher member is introduced as an intermediary tool between the upper electrode and the bolt head. The pusher member has a smaller contact area than the upper electrode, allowing it to apply force to insert the shaft without crushing the projection on the bolt head top surface. This mediator enables shaft insertion while preserving the welding surface integrity.
Solution Approach 2:
The pressing function is segmented into two distinct stages: first, the pusher member presses the bolt head for shaft insertion; second, the upper electrode presses the bolt head for welding. This segmentation allows each operation to be performed with appropriate pressure and contact area, preventing projection crush during insertion while ensuring proper welding contact later.
2Strength
If the upper electrode presses the top surface of the bolt head for welding, then the welding contact is achieved, but the projection crush causes improper welding quality
Solution Approach 1:
The shaft insertion action is performed preliminarily using the pusher member before the welding operation. By completing the insertion task first with a dedicated tool (pusher member), the subsequent welding operation can focus solely on providing adequate contact pressure without concern for projection crush, since the pusher member has already prepared the bolt in the correct position.
Solution Approach 2:
The pusher member serves as a mediator that handles the insertion function, allowing the upper electrode to focus on the welding function. This separation of functions enables the upper electrode to apply sufficient pressure for strong welding bonds without the harmful side effect of crushing the projection, as the pusher member protects the projection during the insertion phase.
3Device complexity
If a single pressing operation is used for both shaft insertion and welding, then the process is simplified, but the projection crush occurs leading to welding defects
Solution Approach 1:
The single pressing operation is segmented into two distinct operations: a first pressing operation using the pusher member for shaft insertion, and a second pressing operation using the upper electrode for welding. Although this increases the number of components, it ensures reliable welding quality by preventing projection crush through the use of appropriately sized contact areas for each operation.
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
Reduces projection crush during welding, ensuring a secure bond between the bolt head and workpiece while maintaining system compactness.
Implementation Method 1
The upper electrode presses the top surface of the head of the bolt from above, which is the first pressurization onto the top surface of the head of the bolt from above
Implementation Method 2
When a current is applied between the upper and lower electrodes, the top surface of the head of the bolt is welded to the lower surface of the workpiece
Implementation Method 3
the pusher member protruding from the tip end of the upper electrode pushes the area, where the projections are absent, of the top surface of the head of the bolt
Data Source
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AI summary
A bolt feeder supplies a bolt to a resistance welding machine that performs resistance-welding of a workpiece and the bolt using a lower electrode that is stationary and an upper electrode that moves up and down. The bolt feeder includes: a holder configured to receive the bolt fed by a chute at a receiving position with a head located above a shaft; a cylinder configured to move the holder holding the bolt from the receiving position to a welding position; and a pusher having a smaller diameter than the upper electrode and configured to protrude from and retract into a tip end of the upper electrode. The bolt includes a projection on a top surface of the head which is opposite to a surface provided with the shaft. The lower electrode includes an insertion hole into which the shaft is inserted. The shaft is inserted into the insertion hole when the pusher member which protrudes from the top of the upper electrode pushes an area of the top surface where the projection is absent.