Torque Limiting Driver Clutch with Curved Cam Override
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing torque limiting drivers for mechanical devices, particularly in medical applications, suffer from damage to moving parts due to excessive pressure on bearings when limiting torque, leading to reduced effectiveness and consistency.
Innovation Solution
A clutch assembly with radially spaced flat areas and curvilinear recesses on the driving plate and opposing downwardly sloped planar surfaces on the camming plate, along with arched wheels and a pin locking mechanism, minimizes stress on rolling members by allowing them to move to an override position, reducing compression and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ball bearings are placed between clutch plates to limit torque, then torque delivery is controlled, but the bearings suffer damage from excessive pressure when torque cut-off occurs
Solution Approach 1:
The patent employs curved cam surfaces instead of flat surfaces in the clutch mechanism. The cam surfaces are designed with specific radii of curvature that allow the ball bearings to roll smoothly during normal operation and then redirect them to a safe position during torque cut-off, reducing impact forces and extending bearing life while maintaining reliable torque control.
2Reliability
If the two clutch plates sandwich the bearings to prevent further torque, then torque limiting is achieved, but the bearings experience smashing action that causes damage
Solution Approach 1:
The patent extracts the ball bearings from the direct compression path between the clutch plates during torque cut-off. The cam mechanism redirects the bearings to a separate chamber or safe position where they are not subjected to the smashing action of the clutch plates, thereby maintaining effective torque limiting while preventing bearing damage.
3Power
If high torque is delivered to meet medical application requirements, then sufficient driving force is provided, but the moving parts experience increased stress and wear
Solution Approach 1:
The curved cam surfaces are designed to optimize the distribution of forces during high torque delivery. The specific curvature profiles ensure that loads are distributed evenly across the contact surfaces, reducing stress concentrations and minimizing wear on moving parts while maintaining the required torque delivery capacity for medical applications.
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 design extends the useful life of the driver by reducing stress on moving parts, ensuring consistent torque delivery and precision, even under high torque conditions.
Implementation Method 1
a plurality of rolling members housed between the two clutch members. The rolling members are movable from an engaged position with the clutch members to an override position
Implementation Method 2
The second camming clutch member has a face comprising a plurality of radially spaced flat areas and a plurality of opposing downwardly sloped planar surfaces interposed between said flat areas
Data Source
AI summary
A clutch assembly for use with a torque limiting driver. The clutch assembly comprises two relatively roatable clutch plates, a driving plate and a camming plate, that face one another, with a plurality of rolling members housed between the two members. When the rolling members are in the override position, the recesses form individual housings for the rolling members that include a gap located between the rolling members and a respective curvilinear base area of the drive plate. The clutch assembly is secured to a drive shaft by a pin, which is supported by a pair of wheels located on opposing sides of the pin.