Truck-Mounted Concrete Pump Boom Force Limiting Circuit

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Solution Overview

Problem

Existing truck-mounted concrete pumps face self-damage issues during transport due to incorrect operation, leading to unwanted plastic deformation or damage to the substructure and chassis, as the boom arm assembly is not adequately protected against excessive force.

Innovation Solution

Integration of a force sensory element into the load path for the arm assembly, coupled with a protective circuit that automatically terminates the depositing movement when a limit load is reached, using a switch or sensor unit attached between the arm assembly and the mast support unit, which includes an elastically deformable load-bearing element and a hydraulic actuator to limit the tracking force without increasing the driving weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the boom arm assembly is pressed down hard by the hydraulic cylinder to improve fixation during transport, then the fixation stability is improved, but the substructure or chassis may suffer plastic deformation or damage due to excessive force

Engineering Contradiction:
Improvefixation stabilityVSAvoidsubstructure strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

A load-bearing element with elastic deformation capability is integrated into the load path between the boom arm assembly and the mast support unit. This element acts as a mechanical fuse that deforms elastically under excessive load, automatically limiting the force transmitted to the substructure and preventing damage before it occurs.

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

Solution Approach 2:

The load-bearing element serves as an intermediary component between the boom arm assembly and the mast support unit. It mediates the force transmission by deforming elastically when the deposit limit force is reached, thereby protecting the substructure from excessive forces while still allowing proper fixation during normal operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If reinforcement of the substructure is added to prevent damage from excessive boom force, then the substructure strength is improved, but the driving weight increases

Engineering Contradiction:
Improvesubstructure strengthVSAvoiddriving weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

Instead of reinforcing the substructure to handle excessive forces, a load-bearing element with elastic deformation capability is integrated into the load path. This element acts as a mechanical fuse that deforms elastically under excessive load, automatically limiting the force transmitted to the substructure and preventing damage before it occurs.

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

Solution Approach 2:

The load-bearing element is designed as a sacrificial component that can be replaced if damaged, rather than making the entire substructure more robust. This approach is more economical and keeps the overall vehicle weight lower compared to reinforcing the substructure.

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

3Reliability

If a protective circuit with force sensory element is integrated into the load path, then the protection against self-damage is improved, but the device complexity increases

Engineering Contradiction:
Improveprotection against self-damageVSAvoidprotective circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The load-bearing element with elastic deformation capability serves as a self-regulating protective mechanism. It automatically limits the force in the load path when the deposit limit force is reached, without requiring external control systems or complex sensing mechanisms. The element itself provides the protective function through its mechanical properties.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The protective function is achieved through a simple mechanical element (load-bearing element with elastic deformation) rather than complex electronic sensing and control systems. This mechanical approach is more reliable and less complex while providing effective protection against self-damage.

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

4Difficulty of detecting and measuring

If the arm assembly is supported only through the load-receiving element, then the load path is clearly defined and force detection is simplified, but the structural complexity increases

Engineering Contradiction:
Improveforce detection difficultyVSAvoidstructural complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The support structure is segmented such that the boom arm assembly is supported only through the specific load-receiving element attached to the mast support unit. This clear segmentation defines a single load path, making force detection straightforward while isolating the complexity to a localized component rather than the entire structure.

Inventive Principle:
Principle #1Segmentation

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

Prevents self-damage by automatically limiting the mast drop force, allowing for safe transport without reinforcing the substructure, and providing a fast-reacting shutdown mechanism with a signal alert for the operator, ensuring the boom arm assembly is supported only through the load-receiving element, effectively protecting the vehicle from excessive loads.

Implementation Method 1

The switching unit has a load bearing element which is arranged on the mast support unit and is elastically deformable when the arm assembly is put down

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the load bearing element has a spring arrangement that can be compressed by the arm assembly, in particular a disk spring assembly

Methodology Applied
Scientific EffectSpring compression: Spring

Implementation Method 3

the protective circuit has a hydraulic actuator connected to the hydraulic cylinder, in particular a directional control valve

Methodology Applied
Scientific EffectHydraulic force: Hydraulic Press

Data Source

PatentEP3094793B1Truck-mounted concrete pump
Publication Date: 2018.03.14 PUTZMEISTER ENG GMBH
  • EP3094793B1 patent drawingFigure 1~2

AI summary

The invention relates to a truck-mounted concrete pump comprising a vehicle (12) and a concrete spreading boom (16) which is disposed on the vehicle (12) and includes a plurality of boom arms (22) that can be stowed, in the form of an arm assembly (24), on a vehicle-mounted boom supporting unit (14), and a boom hydraulic system which is designed to stow and unfold the arm assembly (24) and which includes a hydraulic cylinder (30) that moves the arm assembly (24) towards the boom supporting unit (14) in a stowing movement. In order to limit the boom stowing force, a protective circuit (20) which is coupled to the hydraulic cylinder (30) and automatically ends the stowing movement comprises a switching unit (32) that can be actuated under the load of the arm assembly (24).