Mobile Crane Counterweight Arrangement for Compact Swivel Radius
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Solution Overview
Problem
Mobile cranes with movable counterweight arrangements face challenges in adjusting ballast radius effectively while minimizing the swivel radius, particularly in narrow construction sites where interference with structures like building walls occurs.
Innovation Solution
A mobile crane design featuring a counterweight arrangement with swiveling counterweight stacks on a base plate, allowing for adjustable ballast radius through rotary movement, and equipped with hydraulically or electrically operated swivel drive units, enabling continuous adjustment and reduced swivel radius, along with the option to separate the counterweight for transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the counterweight arrangement is shifted backward to increase the counter-torque, then the counter-torque is improved, but the swivel radius of the superstructure increases causing interference with building walls or other structures
Solution Approach 1:
The patent transitions from linear movement of counterweights along the superstructure to radial arrangement of counterweight stacks around the superstructure's vertical axis. By positioning counterweights at different radial distances from the axis, the system achieves variable counter-torque without increasing the horizontal swivel radius, effectively utilizing the radial dimension to resolve the contradiction between torque generation and space occupation.
Solution Approach 2:
Different counterweight stacks are positioned at different radial distances from the superstructure's vertical axis, creating local variations in counter-torque contribution. This allows selective activation of specific stacks to achieve the required counter-torque while maintaining a compact overall swivel radius, addressing the contradiction by optimizing local weight distribution rather than uniform linear placement.
2Force
If linear piston and cylinder arrangements are used to move the counterweight arrangement, then the counter-torque can be adjusted, but the adjustment path is limited and the swivel radius increases
Solution Approach 1:
The patent replaces linear adjustment mechanisms with a radial arrangement where counterweight stacks can be positioned at different distances from the superstructure's vertical axis. This radial configuration provides a much larger effective adjustment path for counter-torque variation without requiring long linear travel distances, thereby increasing the adjustment range while minimizing the swivel radius.
Solution Approach 2:
The counterweight stacks are made dynamically repositionable around the superstructure, allowing continuous adjustment of their radial position. This dynamic arrangement enables flexible adaptation of the counter-torque by moving stacks radially inward or outward, providing a large adjustment path in a compact configuration that avoids the limitations of fixed linear mechanisms.
3Adaptability or versatility
If the counterweight arrangement is made movable to adjust ballast radius, then the adaptability is improved, but the device complexity increases with additional mechanisms
Solution Approach 1:
The counterweight arrangement is segmented into multiple independent counterweight stacks that can be individually positioned at different radial distances from the superstructure's vertical axis. Each stack can be independently adjusted to achieve the desired ballast radius and counter-torque, providing high adaptability while keeping each individual mechanism simple and modular.
Solution Approach 2:
The radial positioning mechanism serves multiple functions: it adjusts the ballast radius, controls the counter-torque, and enables compact storage of the counterweight arrangement. By making the mechanism multi-functional, the patent achieves high adaptability without proportionally increasing complexity, as a single radial adjustment system accomplishes what would otherwise require multiple separate mechanisms.
Data Source
AI summary
The invention concerns a mobile crane with a drivable undercarriage and a rotatable superstructure mounted thereon, where on the one side there is pivoted a swiveling jib, and on the other side a counterweight arrangement is mounted which is movable relative to the superstructure. According to the invention, the counterweight arrangement has a counterweight base plate, on which at least two stacks of counterweights are arranged and able to swivel about a vertical axis.