Loading Crane Tool Coupling for Zero-Play Force Transmission
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Solution Overview
Problem
Existing quick couplers for loading cranes do not adequately address the need for improved force transmission and zero-play connection between the crane and work tools, particularly during frequent tool changes.
Innovation Solution
A system comprising first and second coupling members with a receiving opening and a guide member, respectively, that engage axially with a locking element capable of moving at right angles to provide axial clamping and direct force transmission, ensuring zero-play coupling and precise movement of work tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional quick couplers are used for frequent work tool changes, then tool change speed is improved, but force transmission and connection stability deteriorate
Solution Approach 1:
The locking element is designed to move between a retracted position (during coupling) and an extended locking position (during operation). This dynamic positioning allows the system to transition from a coupling state to a locked state, maintaining both quick change capability and operational stability. The locking element can be actuated by hydraulic or pneumatic pressure to extend into the transverse bore, creating a positive mechanical lock that prevents relative motion between coupling members.
Solution Approach 2:
The locking element is nested within the coupling member structure, specifically moving along the guide member and engaging with the transverse bore. This nested configuration allows the locking mechanism to be compact while still providing effective force transmission. The guide member itself is nested within the coupling assembly, creating a hierarchical structure that maximizes space utilization while maintaining functional integrity.
2Productivity
If conventional quick couplers are used for direct force transmission, then coupling speed is improved, but play or clearance in the connection increases
Solution Approach 1:
The coupling members are designed with asymmetric geometries including a pin-shaped guide member on one side and a complementary cup-shaped receiving element on the other. This asymmetric design ensures that the guide member fits precisely into the receiving opening, eliminating play or clearance. The transverse bore for the locking element is positioned asymmetrically to optimize the locking geometry and force transmission path.
Solution Approach 2:
The guide member and receiving opening are designed to self-align during the coupling process. As the coupling members approach each other, the guide member automatically engages with the receiving opening in the correct orientation, pre-positioning the locking element for subsequent engagement. This preliminary alignment action ensures zero-play connection without requiring additional adjustment steps.
3Strength
If locking elements are used to retain coupling members, then connection strength is improved, but torque transmission capability deteriorates
Solution Approach 1:
The force transmission function is segmented between two distinct components: the locking element provides axial retention and connection strength, while the support surface and bearing surface provide torque transmission. This segmentation allows each component to be optimized for its specific function without compromising the other. The locking element can be a simple bolt-shaped component that only needs to prevent separation, while the torque is transmitted through the larger contact surfaces.
Solution Approach 2:
The support surface and bearing surface act as intermediary elements between the locking element and the external loads. These surfaces transfer the torque and radial forces away from the locking element, allowing the locking mechanism to focus solely on axial retention. The intermediary surfaces distribute the mechanical stresses across larger areas, reducing the burden on the locking element.
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 system achieves precise positioning and high load capacity for work tools by ensuring zero-play axial clamping and direct force transmission, while reducing vibration-induced wear and allowing for efficient torque transmission.
Implementation Method 1
The locking element has a clamping surface for frictionally abutting the first coupling member. The interaction between the clamping surface and the abutment surface ensures axial clamping and a direct transmission of force
Implementation Method 2
The first coupling member has a support surface for axially abutting the second coupling member, and the second coupling member has a bearing surface complementary to the support surface
Implementation Method 3
The interaction between the clamping surface and the abutment surface ensures axial clamping and a direct transmission of force so that the second coupling member can be coupled with zero play to or by the first coupling member. This allows precise movements of the work tool to be executed and ensures a high positioning accuracy of the work tool. Furthermore, the vibration-induced wear and tear or abrasion of the contacting surfaces on the first and second coupling member can be reduced.
Data Source
AI summary
A system for changing work tools on a loading crane includes a first coupling member on the work tool side or the loading crane side with a receiving opening and a second coupling member on the loading crane side or the work tool side with a guide member extending along a longitudinal axis. The guide member engages in the receiving opening by moving the first and second coupling members toward each other. The first coupling member comprises a support surface for axially abutting the second coupling member and the second coupling member comprises a bearing surface complementary to the support surface and a locking element which is movable by a drive between disengaged and engaged positions. The locking element has a clamping surface for frictionally abutting the first coupling member and the first coupling member has an abutment surface complementary to the clamping surface for zero-play axial clamping of the first and second coupling members.