Thermal Cycler Lid Cam for Multiple Consumable Heights
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Solution Overview
Problem
Existing thermal cyclers struggle to accommodate reaction vessels of varying heights, requiring separate instruments for different consumables and facing issues with thermal resistance and uneven pressure application.
Innovation Solution
An instrument with an adjustable pressure plate operated by a cam and follower mechanism, allowing for the use of multiple consumable heights, and a dual-purpose motor for both lid operation and pressure adjustment, minimizing torque requirements and enabling compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed pressure plate is used in thermal cyclers, then the structure is simple, but it cannot accommodate reaction vessels of different heights
Solution Approach 1:
The pressure plate is made adjustable through a cam mechanism that allows it to be positioned at different heights. The cam profile converts rotational motion into linear displacement, enabling the pressure plate to adapt to various consumable heights while maintaining a relatively simple overall structure.
Solution Approach 2:
A single lid mechanism with an adjustable pressure plate serves multiple functions: it accommodates different consumable heights, applies uniform pressure during thermal cycling, and maintains seal integrity. This multi-functional design eliminates the need for multiple specialized instruments for different consumable types.
2Adaptability or versatility
If separate instruments are used for different consumable heights, then each instrument is optimized for its specific consumable, but it increases the number of instruments needed and reduces versatility
Solution Approach 1:
The thermal cycler is designed with a universal lid mechanism that can accommodate multiple consumable heights through the adjustable pressure plate. This allows a single instrument to perform the function of multiple specialized instruments, improving utilization efficiency and reducing the total number of instruments needed in the laboratory.
3Force
If high force is applied to press vessels against the thermal block, then thermal resistance is reduced, but it causes uneven pressure distribution and potential vessel damage
Solution Approach 1:
The pressure plate is designed with a surface that matches the contour of the consumable tops, distributing force locally across the contact area. This ensures uniform pressure distribution while maintaining adequate force for thermal contact, preventing both insufficient heat transfer and excessive localized stress on the vessels.
4Device complexity
If a dual-purpose motor is used for lid operation and pressure adjustment, then device complexity is reduced, but torque requirements become more challenging
Solution Approach 1:
The cam mechanism uses a curved profile to convert rotational motor motion into linear pressure plate displacement. The cam geometry is optimized to provide mechanical advantage, reducing the torque required from the motor while still achieving the necessary force for pressing vessels against the thermal block. The curved cam surface creates variable leverage throughout the rotation cycle.
Solution Approach 2:
The cam mechanism replaces a more complex dual-motor system with a single motor coupled to a mechanically advantageous linkage. The cam-follower arrangement transforms the motor's rotational output into the linear motion needed for pressure adjustment, eliminating the need for a separate actuator while maintaining precise control over both lid position and pressure force.
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
Facilitates the use of multiple consumable heights in a single instrument with efficient heat transfer and uniform pressure application, reducing motor wear and tear, and enabling a compact, reliable thermal cycler design.
Implementation Method 1
An adjustable pressure plate 200 is provided and configured to contact the consumable 310. The adjustable pressure plate 200 may be operated using a cam and follower mechanism
Implementation Method 2
The thermal block is heated and cooled either by a Peltier heating/cooling apparatus or by a closed-loop liquid heating/cooling system that circulates a heat transfer fluid through channels machined into the block
Implementation Method 3
The thermal block is heated and cooled either by a Peltier heating/cooling apparatus, which may be a single Peltier module or an array of modules
Data Source
AI summary
An instrument (e.g., a thermal cycler) includes a consumable compartment configured to receive multiple height consumables, and a lid for opening or closing the consumable compartment. The lid includes a motor, a pressure plate, a compression bar, and a cam and a follower. The compression bar has a first side (e.g., bottom) coupled to the pressure plate and a second side (e.g., top) at which the cam and the follower is disposed. The cam is drivably coupled to the motor and the follower is coupled to the compression bar to induce translation of the compression bar when engaged with the cam. The cam includes a cam profile configured to adjust a height of the pressure plate between different height consumables to apply a pre-determined pressure. The motor can also operate a latch assembly to latch the lid before activating the cam and follower assembly.