Lockable Precision Adjustment Screw for Cryogenic Vacuum Alignment
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Solution Overview
Problem
Existing methods for adjusting the focus or position of infrared focal plane detector arrays within vacuum housings are cumbersome and time-consuming, often requiring the movement of the entire vacuum housing or using vacuum feedthrough tools that cause thermal shorts and vacuum loss, and do not allow for tilting adjustments.
Innovation Solution
A lockable precision adjustment screw mechanism with a push-pull screw and ball-and-socket joints, integrated with a vacuum bellows, enables precise tilting and positioning of optical elements within a vacuum chamber without moving the housing, maintaining vacuum and cryogenic conditions, and allowing real-time feedback during adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vacuum feedthrough tools are used to adjust cold push-pull screws, then adjustment can be made through the vacuum wall, but thermal shorts occur and vacuum is lost
Solution Approach 1:
A magnetic coupling system acts as an intermediary between the external adjustment tool and the internal push-pull screw. The magnetic field transmits rotational force through the vacuum wall without physical contact, eliminating thermal shorts and vacuum loss while enabling precise adjustment of the cold optics
2Manufacturing precision
If the entire vacuum housing is moved for focus adjustment, then the detector position can be changed, but the vacuum port interface and external cables must be moved which is not feasible
Solution Approach 1:
The adjustment function is segmented from the entire vacuum housing system. Instead of moving the whole housing, only the specific push-pull screw and platform are adjusted through magnetic coupling, while the vacuum housing, ports, and cables remain stationary
Solution Approach 2:
The adjustment mechanism is extracted from the vacuum housing interior and operated from the exterior through magnetic coupling. This allows the adjustment function to be separated from the housing movement requirement, eliminating the need to reconfigure vacuum ports and external cables
3Measurement precision
If multiple iterations of alignment adjustment are performed under vacuum, then precision can be achieved, but time and cost increase significantly
Solution Approach 1:
The mechanical adjustment system is replaced with a magnetic coupling system that provides finer resolution and more precise control. This substitution enables smoother, more accurate adjustments that reduce the number of iterations needed to achieve optimal alignment precision
4Adaptability or versatility
If linear motion vacuum feedthrough micrometers are used, then linear or rotational motion is provided, but tilting adjustment is not possible
Solution Approach 1:
The rigid linear motion mechanism is replaced with a dynamic magnetic coupling system that can accommodate multiple degrees of freedom. The magnetic field allows the push-pull screw to perform linear motion, rotational motion, and tilting adjustments, providing versatile motion types while maintaining a relatively simple overall structure
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
Enables precise and efficient adjustment of cryo-cooled detectors or optics within a vacuum chamber without thermal shorts or vacuum loss, allowing the vacuum housing to remain in place and eliminating the need for special tooling, while providing excellent dimensional stability and reducing the number of alignment iterations.
Implementation Method 1
A magnetic coupling mechanism allows adjustment of the push-pull screw from outside the vacuum wall
Implementation Method 2
A ball-and-socket type joint between the platform and the base, with the platform tiltable with respect to the base about the ball-and-socket type joint
Data Source
AI summary
A precision adjustment screw mechanism comprises a platform carried by a base. The platform is selectively movable towards and away from the base, and is selectively tiltable with respect to the base. A push-pull screw is secured to and between the platform and the base, to selectively displace the platform towards and away from the base. The push-pull screw has a ball-and-socket type joint between the platform and the base, with the platform tiltable with respect to the base about the ball-and-socket type joint. A cylindrical bellows has a proximal end sealed to the base and a distal end sealed to the platform, and circumscribes the push-pull screw between the base and the platform. The bellows can react torque exerted on the platform by a fastener of the push-pull screw.