Crane Pin Actuator Motion Mitigator for Stuck Pins

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Solution Overview

Problem

Existing pin actuator assemblies for telescoping booms in cranes face issues with movement impediments due to stuck pins caused by entrained air, cold temperatures, and misalignment, leading to unreliable operations and potential damage to electric actuators.

Innovation Solution

A pin actuator assembly incorporating a motion mitigator that absorbs movement of the drive arm when cylinder or section pins are impeded, using a rod and springs to apply a preload to the operating plate, ensuring intended movements are completed without further actuator operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hydraulic trombone cylinder is used to actuate pins, then the pins can be actuated, but entrained air and cold temperatures cause unreliable operation and pressure deflection may deflect the rod or cylinder causing pins to become stuck

Engineering Contradiction:
Improvepin actuation reliabilityVSAvoidentrained air and cold temperature effects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the hydraulic trombone cylinder with an electric actuator that mechanically drives the operating plate through a drive arm. This substitution eliminates the reliability issues associated with hydraulic systems (entrained air, cold temperature sensitivity, pressure deflection) while maintaining the pin actuation function. The electric actuator provides direct mechanical motion without the intermediary hydraulic fluid system.

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

Solution Approach 2:

The patent introduces a motion mitigator as an intermediary component between the electric actuator and the operating plate. This motion mitigator absorbs unintended movements when pins are impeded, protecting the electric actuator from damage while allowing the pin actuation system to continue functioning. The motion mitigator acts as a buffer that decouples the actuator from the pin movement constraints.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the control system operates the linear boom actuator and electric actuator to move pins to desired positions, then pin positioning is achieved, but repeated attempts when pin movement is impeded may result in damage or premature wear to the electric actuator

Engineering Contradiction:
Improvepin positioning accuracyVSAvoidelectric actuator durability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The motion mitigator is pre-configured to absorb unintended movements of the electric actuator when pin movement is impeded. This beforehand cushioning protects the electric actuator from damage or premature wear that would result from repeated actuation attempts, while still allowing the control system to achieve accurate pin positioning when conditions permit.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If cylinder pins and section pins are positioned to engage boom sections, then telescoping movement is controlled, but pins may become stuck due to misalignment or environmental factors requiring delayed operations

Engineering Contradiction:
Improvetelescoping boom operationVSAvoidpinning operation delay
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The motion mitigator automatically absorbs unintended movements of the electric actuator when pins encounter impediments, eliminating the need for operator intervention to reset or adjust the system. This self-service function allows the pin actuation system to handle misalignment or environmental factors autonomously, reducing operation delays while maintaining ease of use.

Inventive Principle:
Principle #25Self-service

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 motion mitigator effectively mitigates movement impediments, allowing the pin actuator assembly to complete intended movements without further actuator operation, reducing wear and maintenance costs by ensuring pins are properly positioned without repeated attempts.

Implementation Method 1

A motion mitigator is operably connected to the actuator and configured to mitigate movements of the actuator when movement of the operating plate is impeded. The motion mitigator includes a rod and a spring operably connected to the rod such that the spring applies a preload to the operating plate.

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3757054B1Electric actuation assembly for crane pinned boom
Publication Date: 2023.08.02 MANITOWOC CRANE CO LLC
  • EP3757054B1 patent drawingFigure 1
  • EP3757054B1 patent drawingFigure 2
  • EP3757054B1 patent drawingFigure 3

AI summary

A pin actuator assembly (10) for a telescoping boom (110) includes a locking head (12) having a base (18), an operating plate (20) operably coupled to the base, one or more cylinder pins (22) and/or one or more section lock arms (28) movable in response to movement of the operating plate relative to the base. The pin actuator assembly also includes an actuator (14) operably coupled to the operating plate and configured to move the operating plate relative to the base. The actuator includes an electric motor (34) and a drive arm (36). The electric motor is configured to drive the drive arm between an extended drive arm position and a retracted drive arm position. The pin actuator assembly further includes a motion mitigator (16) having a housing (46), a rod (38) movable relative to the housing and operably coupled to the actuator, a first biasing member (40) and a second biasing member (40).