Inline Piston Pump Assembly With Mechanical Anti-Backlash Drive
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inline piston pumps suffer from mechanical backlash, leading to inaccuracies in fluid dispensing, which cannot be effectively addressed through software calibration due to limitations in modifying existing pump control software.
Innovation Solution
An inline pump assembly with a mechanical anti-backlash mechanism, incorporating a spring-loaded mechanism and a linear slide with ball bearings to prevent rotational movement, ensuring precise fluid dispensing without software modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a linear actuator with lead screw is used to drive the piston, then the pump can achieve automated fluid dispensing, but mechanical backlash causes inaccuracies in fluid dispensing precision
Solution Approach 1:
A belt drive system is introduced as an intermediary between the lead screw and piston rod. The belt acts as a flexible coupling that transmits linear motion while accommodating misalignment and reducing the transmission of backlash errors to the piston, thereby maintaining dispensing precision while preserving automated operation
Solution Approach 2:
The system employs dynamic elements including the flexible belt and spring mechanism that allow for real-time compensation of mechanical play. The spring maintains constant tension on the belt, ensuring continuous engagement without rigid constraints, which dynamically absorbs backlash variations during bidirectional motion
2Manufacturing precision
If software calibration is used to compensate for backlash, then fluid dispensing accuracy can be improved, but it requires modifying existing pump control software which is not accessible or controllable by pump manufacturers
Solution Approach 1:
The patent replaces the software-based compensation approach with a purely mechanical solution. The belt drive system with spring tensioning provides physical backlash compensation through mechanical means, eliminating the need for software calibration and avoiding all associated complexity and access issues
Solution Approach 2:
The spring-loaded belt tensioning system automatically compensates for backlash without requiring external calibration or control. The mechanism self-regulates by maintaining constant belt tension through spring force, providing automatic precision maintenance without software intervention
3Speed
If a shaft key or splined shaft is used to prevent lead screw rotation, then linear motion can be achieved, but play or slop in the system causes step loss when direction of motion is reversed
Solution Approach 1:
A flexible belt is used instead of rigid mechanical couplings like shaft keys or splines. The belt's flexibility allows it to accommodate minor misalignments and absorb shocks, while its tensioned state prevents slack that would cause play. This eliminates step loss during direction reversals while maintaining reliable linear motion transmission
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
Eliminates mechanical backlash, achieving accurate fluid dispensing with ±10 picoliter precision, independent of driver hardware and software updates.
Implementation Method 1
The linear slide includes a rail having a slide block thereon. The linear slide and rail are engaged to prevent rotation of the slide about a longitudinal axis of the rail.
Data Source
AI summary
An inline pump assembly for dispensing fluids, the pump assembly including a pump head, having a piston wherein movement of the piston causes the pump head to dispense a fluid. A linear actuator has a lead screw wherein actuation of the linear actuator causes the lead screw to move along a linear path. A first anti-backlash device is disposed between the linear actuator and the pump head. The anti-backlash device includes a rail having a sliding block thereon. The slide block and rail are engaged to prevent movement of the slide block about a longitudinal axis of the rail. A coupler is fixedly secured to the linear slide and having a first end connected to the lead screw and a second end connected to the piston rod.