Piston Pump Locking Sleeve Skew Prevention
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Solution Overview
Problem
Manual piston pumps with blockable dispensing heads often suffer from skewing issues when the dispensing head is pressed down, leading to incomplete piston strokes, excessive substance delivery, and increased wear.
Innovation Solution
A manual piston pump design where the locking sleeve encapsulates the spring for low-wear pre-tensioning and guides the dispensing head, preventing skewing by forming a track for the outer shaft section and using projections as locking elements to engage with recesses, ensuring reliable locking and compensation for manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dispensing head is pressed down to dispense substance, then substance is delivered, but the dispensing head skews leading to incomplete piston strokes and excessive substance delivery
Solution Approach 1:
The locking sleeve acts as an intermediary component between the dispensing head and the pump chamber. It provides both locking functionality through projections engaging with recesses and guidance through its cylindrical passage, mediating the interaction between the dispensing head and piston rod to prevent skewing while enabling substance delivery.
Solution Approach 2:
The locking sleeve is divided into functional segments: an outer cylindrical surface that forms a guide track for the outer shaft section, an inner cylindrical passage for the hollow piston rod, and locking projections on its outer circumference. This segmentation allows each feature to independently address specific problems (guidance, locking, stability).
2Reliability
If the locking sleeve is fixedly connected to the hollow main part, then the dispensing head can be locked, but increased wear occurs during operation
Solution Approach 1:
The locking sleeve serves as a mediator that distributes and manages multiple functions: it provides locking through projections, guidance through its cylindrical passage, and spring pre-tensioning. This mediation reduces wear on individual components by spreading the functional load across the locking mechanism, guide surfaces, and spring system.
3Ease of operation
If the spring presses the piston rod outwards into rest position, then the dispensing head is pre-tensioned, but the spring may oxidize if exposed to product flow
Solution Approach 1:
The spring is extracted from the product flow environment by positioning it inside the hollow piston rod, which is isolated from the dispensing head's exposure to fluid substances. This extraction protects the spring from oxidation while maintaining its pre-tensioning function on the piston rod.
4Ease of operation
If the outer shaft section moves during piston strokes, then the dispensing head can be actuated, but skewing occurs without proper guidance
Solution Approach 1:
The locking sleeve provides a cylindrical (curved) passage and outer surface for the outer shaft section to move along. This curved geometry provides continuous contact and guidance, constraining the outer shaft section to follow a precise circular path during piston strokes, thereby preventing skewing while enabling smooth actuation.
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 design ensures reliable and low-wear operation by preventing skewing and maintaining functionality, while keeping the spring outside the product flow to prevent oxidation, allowing for precise control of fluid dispensing in both top and bottom positions.
Implementation Method 1
a spring which presses the piston rod outwards in relation to the cylinder, into a rest position
Data Source
AI summary
Manual piston pump having a lockable dispensing head, having a cylinder, an inner locking sleeve forming a cylindrical passage for a hollow piston rod, one end of this extending into a pump chamber of the cylinder and the other end carrying the dispensing head, which is provided with an outer shaft section. A spring presses the piston rod outwards in relation to the cylinder, into a rest position, and in opposition to the spring the piston rod may be lowered by pressing on the dispensing head to dispense substance. To block the dispensing head at least one projection can be placed in engagement with a recess, and the recess has a latching lug arranged on a resilient web articulatedly mounted at the end side and can be latched as a joining partner to the projection.