Mechanical Anti-Backlash Shaft Coupling With Manual Reconnection
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Solution Overview
Problem
Conventional torque transmitting mechanisms face challenges such as backlash during engagement and complex reconnection procedures, particularly due to the need for actuation cables and electrical sensors, which complicate assembly and reconnection, limiting their use to hollow shafts and requiring specialized tools.
Innovation Solution
A mechanical coupling mechanism with sliding and fixed plates, a preloaded leaf spring, and a bellcrank system allows for backlash-free rotational engagement and disengagement with a preset force, featuring a visual indicator for reconnection status and a self-contained design suitable for solid or closed-ended shafts, using a mechanical jack for reconnection and a bellcrank mechanism for disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cable actuation system is used to release the preload and disengage the coupling, then disconnection can be achieved, but the mechanism becomes harder to install and is limited to hollow shafts with open ends
Solution Approach 1:
The patent removes the cable actuation system from the mechanism, extracting the problematic component that caused installation difficulties and shaft compatibility limitations. The disengagement force is now applied directly through the bellcrank mechanism without requiring cable routing through the shaft.
Solution Approach 2:
The mechanism uses its own structural components (bellcrank, lever arms, preload elements) to achieve disengagement without requiring external cable actuation systems. The bellcrank utilizes the applied force directly to overcome the preload and separate the coupling halves.
2Reliability
If an electrical switch and special tools are used to check reconnection status, then proper reconnection can be ensured, but the reconnection procedure becomes difficult and requires specialized equipment
Solution Approach 1:
The patent replaces the electrical switch-based verification system with a purely mechanical visual indicator. The indicator provides direct mechanical feedback about the reconnection status through visible positional changes, eliminating the need for electrical components and special diagnostic tools.
Solution Approach 2:
The visual indicator likely uses color changes or positional visibility to indicate reconnection status. When the coupling is properly reconnected, the indicator assumes a visible position or displays a specific color, providing immediate visual confirmation without requiring electrical testing equipment.
3Reliability
If sliding engagements are used between disks and shaft to achieve axial degree of freedom, then wear and manufacturing deviations are accommodated, but backlash occurs during clutch engagement
Solution Approach 1:
The patent applies a preload force to the friction surfaces before engagement, pressing the friction disks together with sufficient force to eliminate clearance and backlash. This preliminary preloading action ensures that the friction surfaces are already in firm contact when torque is transmitted, preventing any play or slop during operation.
Solution Approach 2:
The mechanism transitions from a static preload application to a dynamic engagement process where the bellcrank lever arm rotates to apply and then maintain the preload force. The dynamic action of the bellcrank allows for smooth engagement while maintaining consistent friction surface contact.
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 precise rotational engagement without backlash, easy manual disconnection with a controlled force, and simplifies installation by eliminating the need for actuation cables, allowing the mechanism to be used as a Line Replacement Unit (LRU) on various shaft types.
Implementation Method 1
a leaf spring having a preloaded spring force exerted on the sliding plate when the sliding and fixed plates are operably connected to one another
Implementation Method 2
The sliding plate may include a circumferential internal sliding plate groove, while the hub may include at least one ball detent which is received within the internal groove of the sliding plate when the hub is in the first position thereof so as to retain the sliding plate in the engaged position thereof
Implementation Method 3
A disconnection bell crank may be operably connected to the inner piston to move the inner piston from the first position to the second position thereof in response to the bell crank being moved into a disconnection position thereof
Implementation Method 4
The plate is fixed to one shaft and the leaf spring is fixed to the other shaft. Such a force-preload ensures friction between plate and leaf spring in addition to the provision of notches that ensure physical engagement between the plate and leaf spring so as to avoid slippage
Data Source
AI summary
Coupling mechanisms for torque transmitting shafts are provided with sliding and fixed plates operably connectable to respective torque transmitting shafts, and a leaf spring having a preloaded spring force exerted on the sliding plate when the sliding and fixed plates are operably connected to one another. A hub is attached to the leaf spring and coaxially received within the sliding plate to allow the sliding plate to be capable of reciprocal axial movements relative to the hub between engaged and disengaged positions wherein the sliding and fixed plates are engaged and disengaged with one another so as to allow and prevent torque being transmitted from one to another of the shafts, respectively. An inner piston is coaxially received within the hub and moveable between a first position wherein the hub retains the sliding plate in the engaged position thereof, and a second position wherein the hub releases the sliding plate to allow movement of the sliding plate under bias force from the leaf spring into the disengaged position thereof.