Foldable Crane Lever Mechanism for Torque Maintenance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Foldable cranes face limitations in maximum horizontal reach and sufficient torque and force for lifting loads due to the positioning of hydraulic cylinders, which results in reduced lifting capacity when the arms approach their maximum extended position, known as the dead centre.
Innovation Solution
The introduction of an additional set of levers for each piston hydraulic cylinder, connected symmetrically and laterally to the lift and articulated arms, maintains a sufficient distance between the hydraulic cylinder's axis and the arms' attachment axis, allowing the crane to avoid the dead centre position and enabling the telescopic arm to extend fully, while allowing the articulated arm to fold above the lift arm, thus maintaining torque and force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the hydraulic cylinder is directly attached to the lift arm and articulated arm, then the structure is simple, but the crane lacks sufficient torque and force when the arms are extended to maximum reach
Solution Approach 1:
A lever system acts as an intermediary between the hydraulic cylinder and the articulated arm. The lever system includes a first lever element connected to the lift arm and a second lever element connected to the articulated arm, with the hydraulic cylinder connecting these two lever elements. This intermediary mechanism maintains a sufficient distance between the hydraulic cylinder's longitudinal axis and the attachment axis of the lift and articulated arms, ensuring adequate torque and lifting force while preserving structural simplicity.
2Length of moving object
If the crane is designed for maximum horizontal reach, then the articulated arm can extend further, but the crane cannot preserve sufficient torque and force for lifting loads
Solution Approach 1:
The lever system serves as a mediator that decouples the relationship between arm extension length and lifting force. By introducing the lever elements with specific pivot points, the system maintains a sufficient perpendicular distance between the hydraulic cylinder's axis and the arm attachment axis, even when the articulated arm is fully extended to maximum horizontal reach. This allows the crane to achieve both maximum reach and sufficient lifting force simultaneously.
Solution Approach 2:
The solution moves the constraint from the horizontal plane to the vertical dimension by positioning the hydraulic cylinder laterally with respect to the lift and articulated arms. The lever system creates a three-dimensional arrangement where the cylinder operates in a different spatial plane, allowing maximum horizontal extension while maintaining the force-generating geometry through the lateral attachment and lever mechanism.
3Force
If the hydraulic cylinder is positioned to maintain sufficient distance from the attachment axis, then torque and force are preserved, but the articulated arm cannot be folded above the lift arm
Solution Approach 1:
The lateral positioning of the hydraulic cylinder with respect to the lift and articulated arms creates a three-dimensional configuration that resolves the folding conflict. The cylinder is attached laterally rather than vertically, allowing the articulated arm to fold above the lift arm in a vertical plane while the cylinder maintains its lateral position and sufficient distance from the attachment axis. This dimensional repositioning enables both full extension for maximum reach and complete folding for compact storage.
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
This configuration enhances the crane's ability to lift heavier loads and reach further, maintaining sufficient torque and force at maximum outreach, and facilitates easier folding and unfolding, overcoming the limitations of existing designs.
Implementation Method 1
A hydraulic system is used for driving the articulated arm with respect to the lift arm. The hydraulic system operated between the lift arm and the articulated arm which contains at least one piston hydraulic cylinder
Implementation Method 2
The piston hydraulic cylinder is mounted on one side to a lever system and on the other side directly to the lift arm. The set of levers consists of two lever elements whose first ends are pivotally connected with the piston hydraulic cylinder and to each other
Implementation Method 3
a lift arm is pivotally mounted, and a lift and articulated arms that are connected to each other through a rotatable coupling to move on the same plane
Data Source
Figure 1
Figure 2~2a
Figure 3~4
AI summary
The object of the invention is a foldable crane that includes a rotatable column (12), to which a lift arm (1) is pivotally mounted through an attachment point (13), an articulated arm (2), in which a telescopic arm (11) can be arranged, wherein the lift arm (1) and the articulated arm (3) are pivotally connected with each other in known ways via attachment point (3), a piston hydraulic cylinder (4) that operates between the lift arm (1) and the articulated arm (2), and a set of levers consisting of a first lever element (5) that has two ends (5a, 5b) and a second lever element (6) that has two ends (6a, 6b). The first lever element (5) and the second lever element (6) are pivotally connected to each other through their first ends (5a) and (6a) in known ways via attachment point (9). The piston hydraulic cylinder (4) is connected to the attachment point (9) with its end (4b), while it is pivotally connected with its end (4a) in known ways with the lift arm (1) via attachment point (7). The first lever element (5) is connected with its end (5b) in known ways with the lift arm (1) via attachment point (8). The second lever element (6) is connected with its end (6b) in known ways with the articulated arm (2) via attachment point (10).