Weight Compensation for Coordinate Measuring Device Z-Axis
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Solution Overview
Problem
Existing coordinate measuring machines face challenges in efficiently compensating for the weight of vertically movable components, leading to increased mass, complex designs, and reduced measurement accuracy due to the need for counterweights and complex pressure regulation in pneumatic systems.
Innovation Solution
A weight compensation device using a spring and conical drums with flexible traction mechanisms, where the traction means are wound and unwound on the drums with varying lever arms to provide uniform weight compensation, reducing the mass increase and eliminating the need for counterweights, and allowing for compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If counterweights are coupled to the Z slide to compensate for weight, then the weight force is compensated, but the moving mass of the Z-axis is approximately doubled which is disadvantageous for the dynamics
Solution Approach 1:
The patent replaces the traditional mechanical counterweight system with a magnetic field-based active compensation system. Electromagnetic actuators generate magnetic forces that actively counteract the gravitational force on the Z-slide, eliminating the need for physical counterweights and thereby reducing the moving mass while maintaining weight compensation functionality.
Solution Approach 2:
The patent employs a pneumatic system with a compressed air cylinder and storage volume to provide weight compensation. The pneumatic pressure acts on a piston to generate an upward force that compensates for the weight of the Z-slide, avoiding the need for mechanical counterweights and reducing the moving mass.
2Device complexity
If the weight force is absorbed solely by the Z-axis drive, then no additional compensation device is needed, but this would require a corresponding design of the drive which would significantly increase the total mass of the Z-axis
Solution Approach 1:
The patent merges the weight compensation function with the existing Z-axis drive system by integrating electromagnetic actuators or pneumatic components into the drive mechanism. This combination allows the drive to perform both positioning and weight compensation functions simultaneously, avoiding the need for separate compensation devices and reducing overall mass.
Solution Approach 2:
The Z-axis drive system is designed to serve multiple functions: both positioning the Z-slide and compensating for its weight. The electromagnetic actuators or pneumatic system are integrated into the drive mechanism, enabling a single system to handle both tasks without requiring additional dedicated compensation devices.
3Force
If pneumatic counterweight with compressed air cylinder is used, then weight compensation is achieved, but complex pressure regulation via precision controller is required
Solution Approach 1:
The pneumatic system is designed to automatically maintain the required pressure for weight compensation through a storage volume that acts as a cushion. The system self-regulates by utilizing the compressed air storage to maintain pressure stability without requiring complex external pressure regulation mechanisms or precision controllers.
Solution Approach 2:
The patent incorporates a compressed air storage volume that serves as a pressure cushion before pressure fluctuations occur. This pre-stored compressed air acts as a buffer to maintain stable pressure during operation, eliminating the need for complex real-time pressure regulation systems.
4Force
If pneumatic counterweight with seals is used, then weight compensation is achieved, but a stick-slip effect can occur which affects the accuracy of the positioning of the probe
Solution Approach 1:
The patent replaces the pneumatic system with seals with an electromagnetic actuator system that uses magnetic fields to compensate for weight. This magnetic field-based approach eliminates physical contact and seals, thereby preventing the stick-slip effect and maintaining high positioning accuracy throughout the measurement range.
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 solution provides more uniform weight compensation with minimal mass increase, improved measurement accuracy, and reduced power consumption, while also enhancing safety by reducing the risk of uncontrolled movements during power failures.
Implementation Method 1
a spring (14) which is designed to exert an elastic restoring force
Implementation Method 2
first, approximately conical drum (17)... second, approximately conical drum (18)... on which the second traction means (19) can be wound and unwound
Data Source
Figure 1
Figure 2a~2b
Figure 3~4b
AI summary
A device according to the invention for compensating the weight (FG) of at least one vertically movable component of a coordinate measuring device (1) comprises a spring, wherein a first end region of the spring is connected to a vertically fixed component of the coordinate measuring device (1), a first traction means, which is connected to a second end region of the spring, opposite the first end region, a first drum on which the first traction means can be wound and from which it can be unwound, a second drum which is coupled in a rotational fashion to the first drum, and a second traction means which can be wound onto the second drum and unwound therefrom and which is connected to the at least one vertically movable component in order to take up at least part of the weight (FG) thereof, wherein the first traction means engages on the first drum with a lever arm which decreases as the wound-on length of the first traction means increases, and/or the second traction means engages on the second drum with a lever arm which decreases as the wound-on length of the second traction means increases. The invention also relates to a method for compensating the weight (FG) of at least one vertically movable component of a coordinate measuring device (1) and to a coordinate measuring device (1).