Blind Rivet Pulling Head Clutch for Jam-Tolerant Position Control
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Solution Overview
Problem
Existing blind rivet fastening devices with electric motors are cumbersome due to the increased number of parts and axial length, and they often fail to properly operate when foreign objects are caught between the pulling head and the nosepiece, leading to clutch malfunction and potential device damage.
Innovation Solution
A compact blind rivet fastening device is designed with a single spindle clutch and nut clutch configuration, which prevents excessive retraction of the pulling head and ensures it does not move forward beyond the home position. This design is positioned closer to the spindle than the ball screw shaft, allowing it to function normally even when foreign matter is caught, thereby protecting the device from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate clutches (front clutch and rear clutch) are equipped to prevent excessive retraction and forward movement, then the reliability of position control is improved, but the device complexity and axial length increase
Solution Approach 1:
The patent combines the functions of the front clutch and rear clutch into a single integrated clutch mechanism. This single clutch has a clutch arm that can engage with different engagement surfaces (first engagement surface for preventing excessive retraction, second engagement surface for preventing forward movement beyond home position), thereby merging two separate clutch systems into one unified component that performs both protective functions.
2Speed
If the clutch is positioned closer to the pulling head, then the response time for preventing abnormal movement is improved, but the risk of foreign object interference increases
Solution Approach 1:
The patent introduces a clutch arm as an intermediary component between the clutch and the ball screw shaft. The clutch arm can rotate about a fulcrum and engage with different surfaces to provide the clutch function. This intermediary mechanism allows the clutch to be positioned closer to the pulling head for faster response while the clutch arm's rotation capability and positioning provide protection against foreign object interference.
3Adaptability or versatility
If the clutch arm is designed to rotate about a fulcrum with engagement surfaces on both sides, then the adaptability to different operational states is improved, but the device complexity increases
Solution Approach 1:
The clutch arm is designed as a universal component that can perform multiple functions by engaging with different surfaces. The same clutch arm engages with the first engagement surface to prevent excessive retraction during normal operation, and engages with the second engagement surface to prevent forward movement beyond the home position. This multi-functional design eliminates the need for separate clutch mechanisms for each function.
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 provides a compact, lightweight blind rivet fastening device with fewer parts, ensuring reliable operation even under abnormal conditions such as foreign object interference, thus preventing device damage and maintaining efficient fastening performance.
Implementation Method 1
a ball screw nut which is adjacent to the spindle and which is connected to the spindle and rotates; a ball screw shaft provided at a central portion of the ball screw nut that moves in the axial direction by rotation of the ball screw nut
Implementation Method 2
a plurality of first segment units are formed on a front plane of the flange unit... a plurality of second segment units complementary in shape to the first segment unit of the spindle clutch, integrally formed with the ball screw nut
Data Source
AI summary
A blind rivet fastening device including a dual function clutch device. The clutch releases at the rear end position RP of the pulling head and the clutch slips at the home position HP. The device includes a spindle clutch axially movable with respect to the spindle and integrally rotated, and a nut clutch integrally formed with the ball screw nut. The spindle clutch can move in the axial direction and can release from the nut clutch. The spindle clutch also has a first segment portion; one end of the first segment portion is a vertical plane and the other end is a slanted plane. The nut clutch has second segment portions of complementary shape. When the pulling head reaches the rear end position RP, the clutch is disengaged. When the pulling head returns to the home position HP, the inclined faces of the clutch slip with each other.