Pump Rod Mounting With Centerline Load Concentration

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Solution Overview

Problem

Axial displacement pumps in fluid dispensing systems face challenges with time-intensive pinning and detaching processes, and experience wear due to misaligned driving forces, which affect the pump rod and various components.

Innovation Solution

A pump rod design with a load concentrating feature and a driving link configuration that secures the pump rod within a cavity using a U-shaped flange, minimizing misalignment and side loading by concentrating forces along the centerline, and a clamping mechanism that aligns and secures the pump to the drive housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pump rod is attached to the reciprocating drive by a pin passing through the pump rod, then the pump rod can be secured to the reciprocating drive, but the process requires loose parts and several tools and is time-intensive

Engineering Contradiction:
Improvesecure connectionVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The pump rod head is integrated directly with the pump rod shaft, eliminating the need for separate pins and loose parts. The head includes a cavity that receives the driving link, creating a unified structure that reduces assembly complexity and time while maintaining secure connection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pin connection is extracted and replaced with a direct cavity-receiving mechanism where the driving link inserts into the head cavity. This removes the intermediate pin component and simplifies the attachment process.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the pump rod is pinned to the reciprocating drive, then the connection can be secured, but detaching the pump rod requires several tools and is time-intensive

Engineering Contradiction:
Improvesecure connectionVSAvoiddowntime
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The integrated head design with cavity allows the driving link to be simply inserted and retained, eliminating the need for pins and multiple tools for detachment. This reduces downtime while maintaining secure connection during operation.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the pump rod experiences driving forces not coincident with the centerline, then the pump can operate, but the pump rod wears on various components of the axial displacement pump

Engineering Contradiction:
Improveoperation capabilityVSAvoidcomponent wear
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The head cavity is specifically designed with a load concentrating feature that localizes the driving force application point. This ensures forces are concentrated at the centerline rather than distributed across the entire head surface, preventing peripheral wear while maintaining operational capability.

Inventive Principle:
Principle #3Local quality

4Manufacturing precision

If the axial displacement pump is threaded into the drive housing, then concentricity can be provided, but the mounting process is complex

Engineering Contradiction:
ImproveconcentricityVSAvoidmounting complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The threaded mounting connection is extracted and replaced with a clamping mechanism. The clamp assembly with adjustable clamping members provides secure mounting without requiring threading operations, reducing mounting complexity while maintaining alignment through the clamp design.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4230868A1Displacement pump mounting and retention
Publication Date: 2023.08.23 GRACO MINNESTOA INC

AI summary

A pump rod has a head extending from a neck, and the head is received within a drive slot of a drive link. The head includes a projection, and has an area smaller than an area of the head. The projection contacts an inner surface of the drive slot. The drive link may include a projection aligned with a centerline of the drive link. The drive link projection contacts a head of the pump rod. The projections provide a reduced contact area between the pump rod and the drive link, thereby reducing any side-loading on the pump rod and increasing a lifespan of the wear parts.