Safety Coupling for Blade Carrier Disc Impact Protection
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Solution Overview
Problem
Rotary multiple-disc mowing machines experience extensive gear damage and downtime due to accidental impacts, leading to high repair costs and machine unavailability when the safety systems fail to prevent blade carrier disc breakage.
Innovation Solution
A supporting and driving assembly with a safety coupling system featuring an axially splined drive shaft, a disc-shaped hub, and Belleville springs with spherical balls that disengage the blade carrier disc from the drive shaft upon impact, allowing for automatic re-engagement once the impact torque is relieved, thus preventing gear breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If easy breakage points or breakage pins are used to prevent gear damage, then gear protection is improved, but machine usability deteriorates due to required part replacements after disengagement
Solution Approach 1:
The coupling system transitions from static rigid connection to dynamic reversible engagement. The balls can engage with the recesses during normal operation to transmit torque, and disengage when impact torque exceeds a threshold, then automatically re-engage when torque is relieved. This dynamic behavior allows the system to adapt to varying operational conditions while preventing gear damage without requiring permanent part replacement.
Solution Approach 2:
The balls are designed to be temporarily discarded from the recesses during impact events, allowing the blade carrier disc to disengage and protect the gears. After the impact torque is relieved, the balls are automatically recovered to their original position, restoring the coupling between the shaft and blade carrier disc. This eliminates the need for manual intervention or permanent part replacement.
2Power
If rigid coupling between shaft and blade carrier disc is maintained, then power transmission is improved, but gear damage risk increases during impact
Solution Approach 1:
The Belleville springs are pre-installed between the balls and the blade carrier disc, providing a cushioning mechanism before impact occurs. When impact torque exceeds the spring force, the springs compress and allow the balls to disengage from the recesses, absorbing the impact energy and preventing direct transmission of damaging forces to the gears. The springs automatically expand to re-engage the balls when impact subsides.
Solution Approach 2:
The balls act as intermediary elements between the shaft and the blade carrier disc. During normal operation, the balls transmit rotational movement and torque from the shaft to the disc. During impact, the balls serve as a mediator that can disengage from the recesses, allowing the disc to rotate independently and protect the gears from direct impact forces. The Belleville springs provide the intermediary force that enables this conditional engagement.
3Reliability
If safety coupling systems are implemented, then gear protection is improved, but device complexity increases
Solution Approach 1:
The coupling system is segmented into distinct functional elements: multiple balls distributed around the periphery, Belleville springs positioned between the balls and blade carrier disc, and corresponding recesses in the blade carrier disc. This segmentation allows each component to perform its specific function independently while working together as a unified safety coupling system. The modular design simplifies manufacturing and maintenance compared to a monolithic solution.
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 solution effectively prevents gear damage by allowing rotational disengagement of the blade carrier disc during impacts, maintaining machine functionality and reducing downtime and repair costs, while enabling easy replacement of worn components like the balls.
Implementation Method 1
The interface between the hub and the plate is provided with a number of balls (22) which are mounted on the hub and project axially from the upper surface (16a) of the hub. The balls (22) are received in corresponding recesses (24) formed in the plate (17). One or more springs (19), in the example here a series of Belleville springs (19), clastically push the plate (17) axially towards the hub (16).
Implementation Method 2
The balls (22) are received in corresponding recesses (24) formed in the plate (17). The balls follow different circular trajectories about the axis of rotation and prevent the disc being locked in an angular position different from the predetermined position.
Data Source
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AI summary
A hub (16) can be fixed to a blade carrier disc (11) and is mounted on a shaft (10) rotationally operated about a vertical axis. In order to transfer the rotary movement from the shaft (10) to the hub (16) a plate (17) rotatable with the shaft and slidable along it is provided adjacent to the hub (16). A spring (19) pushes the plate towards the hub (16). The plate (17) and the hub (16) have corresponding interface surfaces which are inclined with respect to the axis of rotation or curved so as to convert a movement of relative rotation between the hub (16) and the plate (17) into a relative separating movement in an axial direction. In a normal operating condition, the first and second interface surfaces are axially close and mutually engaged in order to transfer the rotary movement from the shaft (10) to the hub (16). Following an impact of the blades of the disc (11) with an external body, the first interface surfaces are disengaged from the second surfaces, axially spaced apart and angularly offset with respect thereto, so that the blade carrier disc and the hub are rotationally disengaged from the plate and the shaft.