Quick-Release Coupling with Secant Pins for Rotary Impact Tools
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Solution Overview
Problem
Conventional couplings for rotating and impacting tools, such as drilling rigs, require significant force and torque for replacement, are time-consuming, and suffer from stress due to high temperatures and force peaks, leading to a demanding design challenge for a quick and durable coupling solution.
Innovation Solution
A quick coupling design that uses a torque-locking mechanism with axially extending driver bolts and secant bores to secure the driver shaft, allowing for easy replacement and robust construction, capable of withstanding high torques and impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional threaded connections are used for coupling, then the connection can withstand high torques and impacts, but the replacement process requires significant force and torque, is time-consuming, and is impractical
Solution Approach 1:
The coupling system is divided into separate components: a drive unit with a drive shaft and a tool holder with a receiving bore. The connection is segmented into modular elements that can be quickly assembled and disassembled without requiring threading operations, enabling rapid tool replacement while maintaining torque transmission capability.
Solution Approach 2:
Instead of using threaded connections that require screwing and unscrewing, the invention inverts the approach by using a friction-based grip mechanism with radial clamping forces. The drive shaft is gripped radially inward by the tool holder through friction and normal forces, eliminating the need for rotational fastening operations and enabling quick release.
2Strength
If conventional threaded connections are used for coupling, then the connection can transmit high torques up to 28,000 Nm, but the coupling is subjected to enormous stress from high force peaks and temperatures, requiring a demanding design
Solution Approach 1:
The coupling design incorporates stress distribution features and friction-based grip mechanisms that preemptively manage the enormous forces and heat generated during operation. The radial clamping forces and friction contact surfaces are designed to distribute and cushion the impact loads before they concentrate on specific components, enhancing reliability under extreme conditions.
Solution Approach 2:
The invention changes the fundamental parameters of the connection mechanism from threaded mechanical engagement to friction-based radial clamping. This parameter change allows the coupling to withstand high torques and force peaks by distributing stresses across larger contact areas and utilizing friction to maintain grip under thermal and mechanical loading conditions.
3Productivity
If a quick coupling design is implemented, then tool replacement becomes fast and easy, but the coupling must robustly withstand high torques and impacts simultaneously
Solution Approach 1:
The coupling employs a dynamic friction-based grip mechanism where radial clamping forces are applied to secure the drive shaft. This dynamic connection allows for quick release by simply reducing the clamping force, while during operation the full radial forces and friction maintain a robust connection capable of withstanding high impact forces and torques.
Solution Approach 2:
The tool holder acts as an intermediary element between the drive unit and the tool, providing a friction-based grip interface on the drive shaft. This intermediary mechanism enables quick tool interchange while robustly transmitting high forces and torques through the friction contact and radial clamping structure during operational conditions.
Data Source
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AI summary
The quick-release coupling allows the lower insertion end (23) of an insertion shaft (44) of a drive device, for example, a drilling machine, to be clamped to an externally circumferential drive sleeve (26) by means of clamping means (38, 39) for transmitting the torque to the tool. The drive sleeve (26) in turn transmits its torque to a drive shaft (57) by means of axially extending drive pins (28, 29), some of which fit laterally into it and the drive shaft (57). Two secant bores (42) lying on the same plane penetrate the edge region of the drive sleeve (26) and intersect the outer region of the drive shaft (57). A fastening pin (27) can be inserted into each of these secant bores (42) for axially securing the drive shaft (57) to the drive sleeve (26).To change the drill bit, simply drive out these two mounting bolts (27) from the secant bores (42) using a hammer and punch, and then the drive shaft (57) can be extended downwards. Installing a new bit with its drive shaft (57) is done in reverse. Drive the two mounting bolts (27) back into the secant bores (42) – done.