Ball Screw Packer Blade Floating Interface

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Solution Overview

Problem

Conventional refuse compaction systems face issues with hydraulic leaks, contamination, slow operation due to large fluid displacements, reduced packing force as arms extend, and heavy construction, leading to increased fuel consumption and maintenance needs.

Innovation Solution

A packer system utilizing a ball screw assembly with a ball nut and floating interface, allowing the packer blade to move within the container with low friction and efficient force distribution across its displacement range, reducing maintenance and fuel consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If telescopic hydraulic rams are used to provide compaction force, then sufficient compaction force can be achieved, but the system becomes heavy and requires large volumes of hydraulic fluid

Engineering Contradiction:
Improvecompaction forceVSAvoidsystem weight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The patent replaces the hydraulic mechanical system with an electric motor-driven ball screw mechanism. The electric motor (140) drives the ball screw (120), which converts rotational motion to linear motion through the ball nut (130), eliminating the need for hydraulic fluid and pumps while reducing system weight and maintenance requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental operating parameters from hydraulic pressure-based force generation to mechanical advantage through ball screw lead and motor torque. This parameter change enables precise control of compaction force while reducing the volume and weight of the power transmission system.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If telescopic hydraulic rams with multiple extension stages are used, then the packer can achieve full displacement range, but the cycle time increases due to slow movement

Engineering Contradiction:
Improvedisplacement rangeVSAvoidcycle time
Core Design Contradiction:
Length of moving objectVSLoss of time

Solution Approach 1:

The electric motor-driven ball screw system provides direct drive capability that eliminates the multi-stage telescopic mechanism. The single-stage ball screw (120) with high lead can achieve the full displacement range (several feet) at high speeds, dramatically reducing cycle time compared to slow-moving hydraulic stages.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses periodic reciprocating motion driven by the electric motor, which can rapidly accelerate and decelerate the packer blade (110) through the full stroke. This periodic action at high frequency reduces the time required for each compaction cycle compared to the gradual extension of hydraulic stages.

Inventive Principle:
Principle #19Periodic action

3Stability of the object's composition

If cross-configured cylindrical arms are used in conventional compaction systems, then structural stability is achieved, but the packing force reduces as the arms extend

Engineering Contradiction:
Improvestructural stabilityVSAvoidpacking force
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The patent replaces the cross-configured cylindrical arm mechanism with a linear ball screw assembly mounted on a stable base. The ball screw (120) maintains a constant mechanical advantage throughout its stroke, ensuring that full compaction force is delivered at all positions within the container, eliminating the force reduction problem of extending arms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention segments the compaction function into a separate linear actuation system (ball screw) from the positioning function, allowing the force-generating mechanism to operate independently of the packer's position within the container. This segmentation maintains constant force capability throughout the displacement range.

Inventive Principle:
Principle #1Segmentation

4Reliability

If conventional hydraulic compaction systems are used, then compaction function is achieved, but maintenance requirements increase due to hydraulic leaks and contamination

Engineering Contradiction:
Improvecompaction functionVSAvoidmaintenance requirements
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The electric motor-driven ball screw system eliminates all hydraulic components (fluid, seals, hoses, pumps) that are prone to leaks and contamination. The enclosed ball screw mechanism with recirculating balls (125) in protected raceways requires minimal maintenance and is immune to the environmental hazards that plague hydraulic systems in refuse handling applications.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electric motor and ball screw assembly represents a simpler, more robust system that can be replaced as a unit if needed, rather than requiring complex hydraulic system repairs. This modular approach reduces maintenance complexity and downtime.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 system achieves faster cycle times, lower maintenance, and consistent compaction force across the displacement range while being lighter and more efficient in terms of fuel consumption compared to conventional systems.

Implementation Method 1

a ball screw assembly generally consisting of a ball screw and a ball nut, each with matching helical grooves, and balls which roll between these grooves providing the only contact between the nut and the screw

Methodology Applied
Scientific EffectBall screw mechanism: Screw

Implementation Method 2

balls which roll between these grooves providing the only contact between the nut and the screw

Methodology Applied
Scientific EffectRolling friction: Friction

Implementation Method 3

The packer blade is coupled to the ball nut via a floating interface. Movement of the ball nut long the ball screw due to rotation of the ball screw forces the packer blade to move within the container. The floating interface allows the packer blade to float within the container with respect to the ball nut.

Methodology Applied
Scientific EffectFloating interface: Ball Bearing

Data Source

PatentEP3333099B1Packer apparatus
Publication Date: 2021.09.08 HARRIS CORP
  • EP3333099B1 patent drawingFigure 1
  • EP3333099B1 patent drawingFigure 2
  • EP3333099B1 patent drawingFigure 3A

AI summary

The present invention is directed toward a packer apparatus (120), which may be used to compact refuse, comprising a container (130) defining a cavity (136), a track (240(1), 240(2)) disposed within the cavity (136), and a ball screw (170(1), 170(2)) rotatably disposed within the track (240(1), 240(2)). The packer apparatus (120) further includes a ball nut (180(1), 180(2)) operatively coupled around the ball screw (170(1), 170(2)), where rotation of the ball screw (170(1), 170(2)) causes the ball nut (180(1), 180(2)) to move along or traverse the ball screw (170(1), 170(2)). A packer blade (160) is coupled to the ball nut (180(1), 180(2)) via a floating interface. Movement of the ball nut (180(1), 180(2)) long the ball screw (170(1), 170(2)) due to rotation of the ball screw (170(1), 170(2)) forces the packer blade (160) to move within the cavity (136). The floating interface allows the packer blade (160) to float within the cavity (136) of the container with respect to the ball nut (180(1), 180(2)) to reduce the likelihood of binding of the ball nut (180(1), 180(2)) on the ball screw (170(1), 170(2)) as the packer blade (160) traverses within the cavity (136).