Knockout Pin Bias Control for Flexible Press Punch Design
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Solution Overview
Problem
Conventional press apparatuses face limitations in design flexibility due to the increasing pushing force of the knockout pin after punching or drawing, which requires strong punches to withstand the force, restricting the ability to shape workpieces without deformation.
Innovation Solution
A press apparatus with a composite punch and knockout pin system, where the knockout pin is biased by compression coil springs and breaking mechanisms to reduce the pushing force after the workpiece is punched out, allowing for more flexible design and preventing bulging deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the knockout pin pushes the workpiece toward the punch to prevent deformation, then the workpiece shape stability is improved, but the punch strength requirement increases, limiting design flexibility
Solution Approach 1:
The punch is divided into a first punch and a second punch that operates independently. The first punch performs the punching operation while the second punch extends downward to hold the workpiece between itself and the knockout pin, allowing the knockout pin to push the workpiece without transmitting full force to the first punch structure.
Solution Approach 2:
The second punch acts as an intermediary between the knockout pin and the first punch. It transmits the pushing force from the knockout pin to hold the workpiece, while the first punch remains structurally independent and does not need to withstand the full pushing force, thereby reducing the strength requirement for the main punch structure.
2Strength
If the punch is made strong to withstand knockout pin force, then the punch strength is sufficient, but the design flexibility is reduced
Solution Approach 1:
By segmenting the punch into two independent components, each can be optimized for its specific function. The first punch can be designed for punching operations while the second punch can be designed to work with the knockout pin, allowing thinner and more flexible designs without compromising strength requirements.
Solution Approach 2:
The second punch is designed to extend downward from inside the first punch only when needed to hold the workpiece with the knockout pin. This dynamic configuration allows the system to adapt its structure based on the operational phase, providing design flexibility while maintaining sufficient strength when required.
3Adaptability or versatility
If the knockout pin pushing force is reduced after punching, then the punch design becomes more flexible, but the workpiece may deform if not properly supported
Solution Approach 1:
The second punch extends downward and positions itself to hold the workpiece between itself and the knockout pin immediately after the punching operation. This preliminary positioning ensures that when the knockout pin pushes the workpiece, the force is contained and directed properly, preventing deformation even with reduced pushing force.
Solution Approach 2:
The second punch serves as a mediator that maintains workpiece stability during the knockout pin operation. It provides a controlled interface between the knockout pin and workpiece, allowing the knockout pin to push with sufficient force to prevent bulging while the first punch structure remains flexible and thin-walled.
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 system reduces the maximum pushing force on the punch, enabling the use of thinner second punches and preventing workpiece deformation, thus enhancing design flexibility and processing efficiency.
Implementation Method 1
a first biasing mechanism including first compression coil springs which apply a first biasing force to the knockout pin upward
Implementation Method 2
a first breaking mechanism including a cam which interrupts transmission of the first biasing force from the first compression coil springs to the knockout pin
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A press apparatus that allows more flexible design for a punch than the conventional technique is provided. A workpiece feeding apparatus 45 (a press apparatus) of the present disclosure includes two, namely, first and second biasing mechanism 151, 152 for applying upward biasing force to a knockout pin 53. At the moment of press work, by the first punch 51 and the knockout pin 53 holding a workpiece 90 therebetween and shifting downward to a die 60, the knockout pin 53 receives biasing force from the first and second biasing mechanisms 151, 152 to press the workpiece 90 from below, so as to prevent the workpiece 90 from bulging deformation. Immediately after the press work on the workpiece 90, the first breaking mechanism 153 breaks transmission of biasing force from the first biasing mechanism 151 to the knockout pin 53. While being less pushed by the knockout pin 53, the workpiece 90 shifts down to the discharge position.