Cam-Controlled Spring Arm Balancing Mechanism
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Solution Overview
Problem
Existing arm balancing devices for pivoting arms about a rotation axis are complex and expensive due to the large number of moving parts and the need for intricate design, particularly in all-purpose fume or gas exhaust conduits, which complicates the regulation of torque variations with angular position.
Innovation Solution
A device that balances torque using elastic means, such as compression springs, controlled by a cam member associated with the arm, which adjusts the spring's action based on the arm's angular position, reducing complexity and cost by simplifying the mechanism and using a cam to manage the precompression force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an articulated parallelogram with eccentric pivot is used to control spring action, then torque balancing performance is satisfactory, but device complexity and production cost increase due to large number of moving parts and intricate rod design
Solution Approach 1:
The patent extracts and eliminates the complex articulated parallelogram mechanism from the balancing device. Instead of using multiple interconnected rods and joints, the invention uses a single cam member that directly controls the spring action, removing unnecessary moving parts while maintaining the torque balancing function.
Solution Approach 2:
The patent inverts the control approach by having the cam member directly act on the spring rather than using the parallelogram to indirectly control it. This inversion simplifies the mechanism by eliminating the intermediate parallelogram linkage and achieving spring control through a single cam profile.
2Ease of manufacture
If an articulated parallelogram is used to house the spring, then spring action can be controlled, but manufacturing cost increases due to intricate rod design and large number of parts
Solution Approach 1:
The patent merges the spring housing function with the cam member itself. The cam member serves dual purposes: it controls the spring action through its profile and simultaneously houses or guides the spring, eliminating the need for separate intricate rod structures and simplifying manufacturing.
Solution Approach 2:
The cam member is designed to perform multiple functions: it acts as the control element for spring action, serves as a structural component, and provides the housing or guide for the spring. This multi-functionality reduces the total number of parts and simplifies manufacturing compared to the specialized parallelogram rods.
3Ease of operation
If elastic means are used to balance torque, then user effort is reduced, but torque variation with angular position requires complex automatic control
Solution Approach 1:
The cam member is designed with a specific profile that automatically adjusts the spring force according to the arm's angular position. As the arm moves, the cam profile self-regulates the spring compression, eliminating the need for external sensors, actuators, or complex control systems while maintaining optimal torque balancing throughout the range of motion.
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 provides a reliable, low-cost, and compact arm balancing device that effectively manages torque variations with angular position, reducing user effort and production complexity, while maintaining performance.
Implementation Method 1
said control means comprise at least one cam member associated with said arm and which acts on said elastic means to control said contrasting action
Implementation Method 2
the torque due to the weight of the arm and any fixture supported by it is balanced by the contrasting action of elastic means
Data Source
AI summary
The torque, due to the weight of the arm, is balanced according to the angular position of the arm by a contrast spring acting perpendicular to the axis of rotation of the arm. The spring is controlled by a cam integral with the arm, is housed in a container closed by a wall acted on by the profile of the cam, and rests on a guide disk whose position relative to the container is adjusted by means of an adjusting screw to calibrate the precompression of the spring according to the minimum torque due to the weight of the arm. In another embodiment, at least one contrast spring acts parallel to the axis of rotation of the arm, and is controlled by a cam edge of a cylinder for axially moving a corresponding sleeve housing the spring.