Fastening Tool Bit Position Control for Reliable Screw Stop
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Solution Overview
Problem
Existing screw driving machines fail to detect the completion of screw fastening operations accurately, leading to continuous operation when sensors break or screws become tilted, resulting in incomplete fastening.
Innovation Solution
A fastening tool equipped with a bit holding portion, first motor, position detector, and controller that determines the forward movement end position of the driver bit, stopping the motor when the end position is not reached or specific conditions are met, ensuring precise control over the fastening process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a sensor is used to detect the driver bit position to determine completion of screw fastening, then the fastening operation can be automatically controlled, but the system becomes vulnerable to sensor failure or misalignment that prevents accurate detection
Solution Approach 1:
The patent introduces a contact member as an intermediary mechanical element that directly contacts the fastening target to detect completion. This mechanical intermediary bypasses the electronic sensor system, providing a reliable backup detection method that is not susceptible to sensor failure or misalignment issues.
Solution Approach 2:
The contact member utilizes the natural completion of the fastening process itself as the detection mechanism. When the screw is fully fastened, the contact member naturally contacts the fastening target, automatically signaling completion without requiring separate detection systems.
2Manufacturing precision
If the driver bit is moved to the forward movement end position to complete fastening, then the screw can be fully driven in, but the operation continues indefinitely when the bit cannot reach the end position due to sensor failure or screw tilt
Solution Approach 1:
The contact member provides immediate mechanical feedback when the fastening target is reached. This feedback mechanism allows the control system to detect completion through the contact member's position state, enabling timely termination of the fastening operation even when the driver bit cannot physically reach the forward end position.
Solution Approach 2:
The contact member is positioned in advance to contact the fastening target at the correct completion point. This preliminary positioning ensures that the contact member will naturally engage with the target when fastening is complete, providing advance warning before the driver bit would otherwise continue moving.
3Reliability
If multiple detection methods are implemented to ensure reliable termination, then operational reliability improves, but device complexity increases
Solution Approach 1:
The patent merges the detection function into the existing mechanical structure of the fastening tool. The contact member is integrated into the driver assembly, combining the fastening and detection functions into a single unified mechanism, thereby avoiding the need for separate complex detection systems.
Data Source
AI summary
A fastening tool includes a bit holding portion configured to detachably hold a driver bit and rotatable in a circumferential direction and movable in an axial direction, a first motor configured to rotate the bit holding portion, a position detector configured to detect a position of the bit holding portion along the axial direction, and a controller configured to drive the first motor to rotate the bit holding portion. The controller is configured to determine, based on the position of the bit holding portion, whether the bit holding portion moves to a forward movement end position and to stop the rotation of the first motor in a case where the bit holding portion does not reach the forward movement end position and a stop condition of the first motor is satisfied.