Toggle Lever Lifting Apparatus with Micrometer Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lifting devices with toggle lever mechanisms are imprecise and inefficient, particularly when moving between rest and working positions, which is problematic for precision applications like grinding cylindrical workpieces in machines.
Innovation Solution
A lifting device with a drive device featuring a toggle lever mechanism where the working position is precisely defined by a positioning device, ensuring the toggle levers remain outside their extended position, allowing for exact positioning and sufficient force application, using a stop surface and adjustment device for micrometer precision, and optionally aided by an auxiliary drive for reduced stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the lifting part is moved using a toggle lever mechanism without a positioning device, then the structure is simpler, but the positioning accuracy deteriorates and cannot achieve micrometer precision
Solution Approach 1:
A positioning device is introduced as an intermediary element between the toggle lever mechanism and the lifting part. This positioning device includes a positioning element that engages with a positioning recess to precisely define the working position, while the toggle lever mechanism provides the lifting motion. The positioning device acts as a mediator that converts the approximate motion from the toggle mechanism into precise micrometer-level positioning.
Solution Approach 2:
The lifting device is segmented into distinct functional components: the toggle lever mechanism for providing lifting motion, the positioning device for defining the working position, and the lifting part for carrying the workpiece. This segmentation allows each component to be optimized for its specific function, with the positioning device focusing solely on achieving micrometer precision independent of the toggle mechanism's structural complexity.
2Measurement precision
If the toggle levers are allowed to reach extended position (180°), then the lifting force is maximized, but the positioning accuracy deteriorates due to excessive play and instability
Solution Approach 1:
The knee joint angle of the toggle lever mechanism is changed from the conventional 180° extended position to a specific range of 170°-178°. This parameter change maintains sufficient lifting force while eliminating the excessive play and instability that occurs at the extended position. The positioning device further refines this by defining the working position at a precise angle within this range, achieving micrometer accuracy without sacrificing lifting capability.
Solution Approach 2:
The positioning device provides feedback control by engaging the positioning element with the positioning recess at a precisely defined working position. This feedback mechanism ensures that the toggle levers remain within the optimal 170°-178° angle range, preventing them from reaching the unstable 180° extended position while maintaining sufficient lifting force through the positioning feedback loop.
3Use of energy by moving object
If the drive device is carried between the base part and tabletop by the lever arrangement, then the structure is more compact, but the mass of the drive has to be moved completely which increases energy consumption
Solution Approach 1:
The drive device is extracted from the moving lever arrangement and relocated to the stationary base part. This extraction eliminates the need to accelerate and decelerate the drive mass during each lifting cycle, significantly reducing energy consumption. The drive device remains fixed on the base part while only the lifting part and workpiece are moved, separating the stationary drive function from the moving lifting function.
Solution Approach 2:
The positioning device acts as a counterbalancing mechanism that offsets the effects of gravitational force on the lifting part. By precisely controlling the position of the lifting part through the positioning element and positioning recess, the system counteracts gravitational effects and maintains stable positioning without requiring continuous energy input, thereby reducing overall energy consumption.
4Manufacturing precision
If the working position is defined without a positioning device, then the device is easier to manufacture, but the working position cannot be adjusted to within a few micrometers
Solution Approach 1:
The positioning device is pre-configured with a positioning element and positioning recess that are manufactured with high precision during the manufacturing process. This preliminary action of precisely manufacturing the positioning components allows the working position to be accurately defined and adjusted to micrometer levels. The positioning device is prepared in advance with the necessary precision features, eliminating the need for complex post-manufacturing adjustments.
Solution Approach 2:
The positioning device serves as an intermediary mechanism that bridges the gap between standard manufacturing tolerances and the required micrometer-level working position precision. By introducing this specialized positioning component, the system achieves high manufacturing precision without requiring the entire lifting device to be manufactured with micrometer tolerances, thus maintaining ease of manufacture for the majority of components.
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 lifting device achieves high accuracy and precise positioning of the lifting part to within micrometer precision, reducing play and stress, enabling reliable operation in precision machine tools.
Implementation Method 1
A lifting device (10) with a lifting part (11) which can be moved linearly in a lifting direction (H) between a rest position (R) and a working position (A) is provided. At least one drive device (18) has a toggle lever mechanism (22)... A drive (19) of the drive device (18) acts on the knee joint (31)...
Implementation Method 2
The toggle lever mechanism (22) has a first toggle lever (22a) which is articulated on the lifting part (11) and a second toggle lever (22b) which is articulated on a base part (17)... The two toggle levers (22a, 22b) are articulated to one another on a common toggle joint (31)
Implementation Method 3
The working position (A) of the lifting part (11) is specified by a positioning device (40)... the positioning device (40) has a stop surface (41) which is facing the lifting part (11)... In this working position (A), the knee joint angle (α) of the toggle mechanism (22) is less than 180°... so that the two toggle levers (22a, 22b) of the toggle mechanism (22) are outside of the extended position
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a lifting apparatus (10) having a lifting part (11) that is movable in a linear manner in a lifting direction (H) between a rest position (R) and a working position (A). The lifting part (11) carries a support unit (13) for a workpiece and/or a clamping unit for this workpiece. In order to move the lifting part (11), at least one drive device and in particular two drive devices (18) are used. Each drive device (18) has a toggle lever mechanism (22) which has a first toggle lever (22a) mounted in a pivotable manner on the lifting part (11) and a second toggle lever (22b) mounted on a base part (17). The two toggle levers (22a, 22b) are mounted in a pivotable manner next to one another at a common toggle joint (31). A drive (19) of the drive unit (18) acts on the toggle joint (32). A positioning device (40) specifies the position of the lifting part (11) in the lifting direction (H) and in particular also transversely to the lifting direction (H) in the working position (A). To this end, it preferably has a stop surface (41) against which the lifting part (11) is pressed into the working position (A) via the at least one drive device (18). In this working position (A), the toggle joint angle α of the toggle lever mechanism (22) is less than 180°, and so the two toggle levers (22a) and (22b) of the toggle lever mechanism (22) are outside the extended position.