Toggle Lever Drive Unit for Press Ram Lifting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional drive units for automatic stamping machines or presses are limited by spindle drives, which restrict processing speed and require oversized designs for lift paths, leading to reduced buckling resistance and increased complexity.
Innovation Solution
A drive unit combining an auxiliary drive for the lift path with a main spindle drive for processing, utilizing a toggle lever system with a fixed stop for mechanical locking and power take-off, allowing for dynamic lift strokes and optimized machining speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a spindle drive is used for both lift path and working stroke, then the drive can perform both functions, but the processing speed is limited and the drive must be oversized for the lift path
Solution Approach 1:
The drive system is segmented into two independent drives: a first drive (auxiliary drive) for the lift path and a second drive (main drive) for the working stroke. This allows each drive to be optimized for its specific function, enabling high-speed lifting with the auxiliary drive while the main drive focuses on precision machining at optimal speeds.
Solution Approach 2:
The auxiliary drive with toggle lever system serves multiple purposes: it performs the lift path function and also provides mechanical locking during the working stroke, eliminating the need for separate locking mechanisms and reducing overall system complexity.
2Adaptability or versatility
If a larger ram stroke is required for greater movability, then the ram can move more freely, but the buckling resistance of the threaded spindle is reduced
Solution Approach 1:
The lifting function is separated from the main spindle drive and assigned to the auxiliary toggle lever system. This allows the main spindle to have a shorter, stronger threaded portion that maintains high buckling resistance, while the toggle lever system provides the extended stroke capability through its geometric mechanism.
Solution Approach 2:
The threaded spindle mechanism is replaced by the toggle lever system for the lifting function. The toggle lever's mechanical advantage and geometric configuration provide the required large stroke without relying on a long threaded spindle, thereby maintaining buckling resistance.
3Force
If a conventional spindle drive is used for the lift path, then the drive can lift the ram, but complex turning and grinding parts are required and the structure is complicated
Solution Approach 1:
The complex threaded spindle mechanism is replaced by a simpler toggle lever system actuated by a rack and pinion or linear drive. This substitution eliminates the need for complex turning and grinding operations on eccentric shafts and spindles, reducing manufacturing complexity while maintaining lifting capability.
Solution Approach 2:
The complex elements (eccentric shaft, threaded spindle with adjustment mechanisms) are extracted from the lifting system and replaced by the simpler toggle lever mechanism. Only the essential lifting function is retained in the auxiliary drive, while complexity is removed.
4Force
If the toggle lever system is used with a fixed stop for mechanical locking, then the pressing forces are absorbed by the stop and bearing point, but the angle must be precisely controlled to exceed 181°
Solution Approach 1:
The toggle lever system automatically achieves mechanical locking when the angle exceeds 181°, using the geometry of the system itself to provide the locking action. The fixed stop simply provides the reference point, and the system's own mechanics ensure proper engagement without requiring external control systems.
Solution Approach 2:
The fixed stop is positioned asymmetrically relative to the toggle lever's motion path, creating a specific geometric relationship that ensures the angle exceeds 181° during normal operation. This asymmetric positioning provides inherent mechanical locking without requiring complex control.
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
This configuration enables higher production speeds, reduced complexity, and increased buckling resistance, while minimizing lubricant use and processing time, with the ability to adapt transmission ratios for optimal performance.
Implementation Method 1
the toggle lever system with upper and lower toggle lever legs, a toggle lever joint and a fixed stop, the toggle levers being able to be locked mechanically by the fixed stop
Data Source
AI summary
The subject matter of this invention is a drive unit for a stamping press or a press for moving a ram (27). According to the invention, the lift stroke is essentially realized by an auxiliary drive (11) and the working stroke by a main drive (20). The subject matter of this invention also includes a method for machining a workpiece in which the drive unit according to the invention is used.