Drive Coupling with Compression Springs for Shock Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Drive couplings in applications like multi-head grass and scrub cutting machines are prone to gear box and drive shaft failure due to sudden shock loads, as standard friction disc type safety clutches cannot provide rotational shock relief, and existing couplings like chain, disc, doughnut, and universal joints do not offer predetermined rotational shock relief.
Innovation Solution
A drive coupling design featuring an inner and outer plate with heavy duty coil springs between them, where the rotation of one plate causes a reaction force transmitted to the other, with precise control over rotational travel through protrusions and recesses to prevent coil bound conditions, allowing for predetermined rotational shock relief and enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard friction disc type safety clutches are used, then shock loads can be relieved, but they cannot be used because cutting blades can only be paused for a few degrees of rotation before contact occurs with adjacent cutting blades
Solution Approach 1:
The patent changes the fundamental parameter of shock relief mechanism from friction-based (clutches) to spring-based elastic deformation. The coil springs provide rotational shock relief through controlled compression and expansion, allowing the inner plate to rotate relative to the outer plate within predetermined limits without requiring friction disc engagement that would pause blade rotation
2Reliability
If chain couplings, disc couplings, doughnut couplings or universal joints are used to couple gear boxes, then mechanical connection is achieved, but none of these devices provide any predetermined rotational shock relief to transmissions
Solution Approach 1:
The coupling device is segmented into an outer plate, inner plate, and multiple coil springs arranged circumferentially. This segmentation allows the spring elements to independently compress and expand, providing distributed shock relief across multiple contact points while maintaining overall coupling integrity
Solution Approach 2:
The coil springs are pre-compressed between the inner and outer plates to store elastic potential energy before shock loads occur. This beforehand cushioning allows the springs to immediately absorb sudden shock loads by compressing further, preventing direct transmission of shock forces to the transmission system
3Reliability
If coil springs are used between inner and outer plates to provide shock relief, then rotational shock relief is achieved, but coil springs may compress to a coil bound (failure) position
Solution Approach 1:
Protrusions are provided on the outer plate that extend inside each coil spring to act as fixed spring guides and rotational travel stops before the springs can compress to a coil bound position. This preliminary action prevents the harmful condition by limiting the maximum compression distance
Solution Approach 2:
The protrusions act as intermediary elements between the coil springs and the outer plate, providing both guidance and hard stops. These intermediaries prevent direct contact between adjacent spring coils during compression, eliminating the coil bound failure mode while still allowing sufficient compression for shock relief
4Measurement precision
If protrusions or projections are used to limit rotational travel of the inner plate, then precise control over rotational travel is achieved, but the device complexity increases
Solution Approach 1:
The protrusions serve multiple functions simultaneously: they act as spring guides to maintain proper spring alignment, rotational travel stops to limit inner plate rotation, and positioning features to ensure correct assembly. This merging of functions reduces the need for separate components and minimizes overall device complexity
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 drive coupling effectively cushions shock loads by compressing springs in a controlled manner, preventing coil bound conditions and minimizing the risk of spring breakage, thus enhancing the reliability and durability of the drive system while maintaining precise control over rotational travel.
Implementation Method 1
a plurality of heavy duty coil springs located between the inner plate and the outer plate. Rotation of the inner plate or the outer plate in the direction of drive causes a reaction force in the plurality of springs
Implementation Method 2
The drive coupling effectively cushions shock loads by compressing springs in a controlled manner
Data Source
AI summary
A drive coupling has an inner plate positioned within an inner periphery of an outer plate. The inner plate includes a plurality of outwardly-extending projections. The inner periphery of the outer plate includes a plurality of recesses. A plurality of short heavy-duty compression springs are arranged to compress in a substantially-straight linear direction between respective projections of the inner plate and the respective side wall of the recess of the outer plate. The springs are further retained by spring travel limiting guides which protrude from the outer plate. The inner plate and an associated central shaft are positively supported by bushings and/or bearings which reside in outer retaining plates. These bushings and/or bearings retain the inner and outer plates in a fixed non-yielding radial and axial position. Bolts are used to hold the outer drive plate and the external retaining plates together. The drive coupling is designed to carry the entire rated torque requirement of the unit on the compression springs, thus providing a continual cushioning action to the drive line whilst providing accurately-controlled angular movement if an obstruction is encountered.