Elastomeric Follower Packing Unit for Grease Gun Sealing
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Solution Overview
Problem
Conventional grease guns face challenges in maintaining an effective seal between the follower assembly and the barrel during bulk loading, and between the follower assembly and lubricant cartridges, leading to grease wastage due to leakage issues.
Innovation Solution
A follower packing unit with an elastomeric seal supported by rigid structural components, featuring a hollow annular body with radial deformation capabilities, and a follower rod system that maintains a unitary structure through fasteners, ensuring a tight seal against both the barrel and cartridges by distributing forces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional follower assembly is used to seal against the barrel during bulk loading, then the seal works for bulk grease, but it fails to adequately seal against cartridges with different inner diameters
Solution Approach 1:
The follower assembly incorporates a resilient seal member that can dynamically adapt its shape and size to match different barrel and cartridge inner diameters. The seal member's flexibility allows it to deform and conform to varying dimensions, providing reliable sealing across both bulk loading and cartridge loading operations without requiring multiple specialized components.
Solution Approach 2:
The seal member's physical parameters (shape, size, flexibility) are designed to change in response to different operating conditions. By varying the seal's dimensional characteristics and material properties, it can effectively seal against both the barrel during bulk loading and cartridges with different inner diameters during cartridge loading, resolving the adaptability-reliability contradiction.
2Ease of operation
If an engagement washer is added to the follower rod to engage the back-up plate during manual priming, then priming engagement is improved, but the sealing surface between the follower rod and seal assembly is disrupted causing grease by-pass
Solution Approach 1:
The engagement washer that was causing sealing surface disruption has been removed from the follower rod design. Instead, the priming engagement function is achieved through alternative means that do not interfere with the sealing interface between the follower rod and seal assembly, thereby eliminating grease by-pass while maintaining ease of priming operation.
Solution Approach 2:
An intermediary mechanism has been introduced to facilitate priming engagement without directly compromising the sealing surface. This intermediary element allows the follower rod to engage the back-up plate during manual priming while preserving the integrity of the grease seal, preventing the harmful by-pass effect.
3Productivity
If the follower seal is pressed forward against the grease tube during priming, then priming action is achieved, but grease by-pass occurs between the follower seal and grease tube
Solution Approach 1:
The follower seal utilizes a flexible shell design that can deform under pressure during priming operations. This flexibility allows the seal to maintain intimate contact with the grease tube inner surface while being pressed forward, preventing grease by-pass. The thin film structure conforms to the tube geometry, ensuring effective sealing during high-productivity priming cycles.
Solution Approach 2:
The seal's dynamic response to forward pressure during priming is optimized to maintain sealing contact rather than create gaps. The seal member's elastic properties allow it to dynamically adjust its position and shape under load, ensuring continuous contact with the grease tube and preventing grease waste even during aggressive priming actions.
4Ease of manufacture
If a rear support is not fastened to the elastomeric seal and retained only by a spring, then assembly simplicity is improved, but seal distortion occurs during follower rod movement causing grease by-pass
Solution Approach 1:
The rear support and elastomeric seal have been merged into a more integrated assembly where the rear support is properly fastened to the seal. This combination ensures that the seal maintains its structural integrity and proper positioning during follower rod movement, preventing distortion and grease by-pass while remaining manufacturable through standard assembly processes.
Solution Approach 2:
The conical sealing surface geometry has been optimized to distribute forces more evenly across the seal interface. The curved, conical configuration helps prevent localized stress concentrations that would cause seal distortion, thereby maintaining seal integrity during dynamic operation while preserving ease of assembly through the fastening mechanism.
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 solution provides a robust sealing mechanism that prevents grease leakage in both bulk and cartridge loading scenarios, maintaining sealing integrity even after numerous cycles, with experimental results showing effective sealing under axial compression and tension forces, significantly improving upon conventional designs.
Implementation Method 1
The annular side wall of the elastomeric seal is resiliently deformable under said pressure in a radial direction for sealing against an interior surface of the barrel or the tubular cartridge
Implementation Method 2
a follower rod for moving the follower packing unit in the barrel along a longitudinal axis of the barrel
Data Source
AI summary
An improved follower packing unit for a grease gun is disclosed. The unit includes a hollow annular body of elastomeric material having a front wall, an annular side wall and a rear wall defining a cavity in the body. Rigid front and back structural supports rigidly support the front and rear walls of the elastomeric seal. The elastomeric seal and the front and back structural supports are fastened together to prevent separation and to form a unitary follower structure movable as a unit on a follower rod. The annular side wall of the elastomeric seal is resiliently deformable under pressure in a radial direction for sealing tightly against an interior surface of the barrel of the grease gun or against the interior surface of a tubular cartridge loaded in the barrel of the gun.