Rivet Table Movable Jaws Eliminate Tool Marks
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Solution Overview
Problem
Existing automatic blind rivet setting devices leave cosmetic tool marks on the exposed rivet heads due to the unsupported slot in the rivet table, which is unacceptable in installations where rivets are exposed, such as in vehicle assembly.
Innovation Solution
A rivet table with opposing movable jaws that pivot around the mandrel to form a continuous surface equal to or larger than the rivet head, eliminating tool marks by supporting the rivet head during setting and allowing the mandrel to move laterally, thus avoiding imprinting on the exposed surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed rivet table with a lateral access slot is used, then the device structure is simple and easy to manufacture, but tool marks are imprinted on the exposed rivet head surface
Solution Approach 1:
The rivet table is segmented into a fixed outer sleeve and movable jaws that can independently pivot. The jaws are separated from the outer sleeve structure, allowing them to move independently to receive and support the rivet head without leaving tool marks, while the outer sleeve remains stationary and simple to manufacture.
Solution Approach 2:
The jaws are made movable rather than fixed, allowing them to pivot open to receive the mandrel and then close to support the rivet head during setting. This dynamic movement eliminates the tool marks that would be caused by a fixed slot structure, while the jaws return to their initial position after each operation.
2Manufacturing precision
If opposing movable jaws are added to the rivet table, then tool marks on rivet heads are eliminated, but the device complexity increases
Solution Approach 1:
The movable jaws are integrated with the outer sleeve through pivot connections, combining the support function with the existing outer sleeve structure. This merging reduces the need for separate complex mechanisms while achieving the goal of eliminating tool marks through the movable jaw design.
Solution Approach 2:
The jaws are biased toward the closed position by spring means, allowing them to automatically return to their initial position after receiving and supporting the rivet head. This self-service mechanism eliminates the need for additional actuators or complex control systems to reset the jaws after each operation.
3Manufacturing precision
If the jaws are biased toward the closed position, then the rivet head is continuously supported to prevent tool marks, but the mandrel cannot easily enter the aperture
Solution Approach 1:
The biasing force on the jaws is designed to be sufficient to hold the rivet head during setting but not so strong as to prevent mandrel insertion. The preliminary positioning of the mandrel in the aperture allows it to overcome the biasing force and open the jaws, after which the biasing force takes over to support the rivet head and prevent tool marks.
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 ensures that the rivet heads are substantially free of tool marks and maintains the seal of watertight rivets during the setting process, improving the cosmetic finish and integrity of the rivet installation.
Implementation Method 1
spring means for biasing the jaws toward the closed position
Implementation Method 2
after the rivet is set and the mandrel fractured away
Data Source
AI summary
A rivet table connected to the nosepiece of a rivet setting apparatus. The rivet table includes an outer sleeve which controllably slides back and forth within the nosepiece and supports opposing jaws pivotally connected to the outer sleeve about spaced transverse pivot axes. The jaws pivot between a closed position and an open position, biased toward the closed position and define a flat transverse distal rivet head receiving surface, and a central mandrel-receiving aperture therebetween to slidably receive a rivet mandrel and to support the rivet head against said rivet head receiving surface during rivet setting. The jaws are momentarily forced into the open position by the mandrel moving laterally into the aperture and being carried on a flexible strip. The exposed surface of the rivet head is thereby substantially free of tool marks after being set.