Hydraulic Rotary Drive for Truck-Mounted Concrete Pump Boom Arms
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Solution Overview
Problem
Existing boom constructions for truck-mounted concrete pumps face challenges in achieving a compact, robust, and space-saving design that allows for uniform pivoting and swiveling of boom arms over a large angle while maintaining balance and preventing unintended rotation when the drive is deactivated, due to the weight and uneven angular velocity issues with traditional coupler gear mechanisms and hydraulic rotary drives.
Innovation Solution
A hydraulic rotary drive system utilizing annular pistons with torque-proof connections via splined serrations and outer rings, which allows for efficient and balanced swiveling and pivoting of boom arms, and self-arresting mechanism to maintain position without separate braking devices when the drive is deactivated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If coupler gear mechanisms with double-acting hydraulic cylinders are used for swiveling boom arms, then sufficient swiveling power is achieved, but the weight and space requirements increase significantly
Solution Approach 1:
The patent replaces the traditional mechanical coupler gear mechanism with a hydraulic rotary drive system. Instead of using mechanical gears and thrust piston gears, the invention employs hydraulic motors directly coupled to the boom arm articulation points, converting linear hydraulic motion into rotational motion more efficiently. This substitution reduces the weight and space requirements while maintaining sufficient swiveling power.
Solution Approach 2:
The invention utilizes hydraulic motors integrated into the boom arm structure to provide rotational motion. The hydraulic system directly drives the articulation joints through hydraulic cylinders connected to the hydraulic motor, eliminating the need for heavy mechanical gear mechanisms. This hydraulic approach reduces both weight and spatial requirements while delivering the necessary swiveling force.
2Power
If coupler gear mechanisms are used for swiveling boom arms, then swiveling power is sufficient, but the device width and length increase, violating road traffic codes
Solution Approach 1:
By replacing the bulky mechanical coupler gear mechanism with a compact hydraulic rotary drive system, the patent significantly reduces the width and length of the boom construction. The hydraulic motors and cylinders have a smaller footprint compared to mechanical gears and linkages, allowing the device to comply with road traffic dimension codes while maintaining full swiveling capability.
Solution Approach 2:
The hydraulic drive components are nested within the boom arm structure itself, with hydraulic cylinders and motors integrated into the existing boom geometry. This nesting approach minimizes the overall width and length of the device by utilizing the internal space of the boom arms rather than adding external mechanical gear assemblies.
3Power
If thrust piston gears are used for swiveling, then swiveling power is achieved, but angular velocity becomes uneven, requiring additional hydraulic load holding valves
Solution Approach 1:
The patent replaces the thrust piston gear mechanism with a hydraulic motor system that provides more uniform angular velocity during swiveling operations. The hydraulic motor's direct coupling to the boom arm articulation points eliminates the intermittent motion and velocity fluctuations characteristic of mechanical gear systems, resulting in smoother and more controlled swiveling without requiring additional load holding valves.
4Ease of operation
If hydraulic rotary drives are used at boom end articulated joints, then uniform angular velocity is achieved, but driving moments are insufficient for lower boom area joints
Solution Approach 1:
The patent applies different drive configurations to different boom arm articulation points based on their specific requirements. Hydraulic rotary drives with uniform angular velocity are used at the boom end joints where lower forces are needed, while more powerful hydraulic cylinder arrangements are used at the lower boom area joints where higher driving moments are required. This segmented approach optimizes performance for each specific location.
Solution Approach 2:
The invention implements local quality by tailoring the drive system characteristics to the specific needs of each boom arm articulation point. The lower boom joints, which require higher forces, are equipped with more robust hydraulic cylinder arrangements, while the upper boom joints, which benefit from uniform motion, use hydraulic rotary drives. This localized optimization ensures both uniform angular velocity where needed and sufficient driving moment where required.
5Reliability
If multiple disk brakes are used to prevent boom arm twisting when drive is deactivated, then safety is improved, but the device complexity and cost increase
Solution Approach 1:
The hydraulic rotary drive system incorporates self-arresting functionality through the inherent characteristics of the hydraulic motor and coupling mechanism. When the hydraulic drive is deactivated, the system automatically prevents unintended rotation of the boom arms without requiring separate braking devices. This self-service approach maintains safety while reducing device complexity and eliminating the need for multiple disk brakes or other mechanical braking systems.
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
Enables compact, balanced, and space-efficient boom construction with uniform angular motion and self-arresting functionality, reducing maintenance and wear, and ensuring safe operation by preventing unintended rotation.
Implementation Method 1
A piston-cylinder arrangement and a gear transforms piston reciprocating movement into rotary movement for boom arm pivoting
Implementation Method 2
first and second hydraulically driven annular pistons
Data Source
AI summary
A boom construction for truck-mounted concrete pumps has at least a first boom arm and a second boom arm that are articulatedly jointed to each other and that are rotatable relatively to each other about an axis. A drive pivots the boom arms. A piston-cylinder arrangement and a gear transform piston reciprocating movement into rotary movement for boom arm pivoting, said arrangement having first and second pistons that form part of the gear and that interact with outer rings of the gear.