Guide Wall for Laminated Spring Assemblies
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Solution Overview
Problem
Conventional counterbalancing mechanisms for robotic surgical arms, relying on laminated constant force spring assemblies, face limitations in space efficiency and safety due to separation of laminations, which reduces counterbalance force and shortens the assembly's lifespan when carrying higher loads.
Innovation Solution
A guide system utilizing rolling elements or static/moving guide surfaces to maintain close proximity of laminations, preventing separation and distributing tension force effectively, allowing for a higher number of laminations within a compact space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of laminations in the spring assembly is increased to improve safety and mechanical redundancy, then the counterbalance force is improved, but the laminations separate from each other requiring more space
Solution Approach 1:
A guide wall is introduced as an intermediary component between the laminations to maintain their close proximity. The guide wall prevents lateral separation of the laminations while allowing them to wind and unwind, enabling increased lamination count without increasing the space required for the spring assembly.
Solution Approach 2:
The guide wall constrains the laminations in the lateral dimension, allowing them to maintain close proximity. This enables the spring assembly to accommodate more laminations by controlling their position in a different dimensional space rather than increasing the overall volume.
2Reliability
If the number of laminations is increased to improve safety and mechanical redundancy, then the counterbalance force is improved, but the separation between laminations becomes more pronounced
Solution Approach 1:
The guide wall serves as a mediator that maintains the stable composition of the lamination stack. By providing a physical barrier that prevents lateral movement, the guide wall ensures that laminations remain in close proximity throughout the winding and unwinding cycle, preventing separation even as the number of laminations increases.
Solution Approach 2:
The guide wall is pre-positioned to constrain the laminations before they can separate. This preliminary constraint action ensures that the laminations maintain their proper alignment and close proximity throughout the entire range of motion, preventing separation issues before they occur.
3Volume of stationary object
If higher loads are carried in a spring lamination to reduce space requirements, then the space for counterbalance system is reduced, but the useful life of the spring assembly is adversely reduced
Solution Approach 1:
The spring assembly is segmented into multiple laminations that share the load. By distributing the tension force across multiple laminations rather than concentrating it in a single lamination, each lamination experiences reduced stress, extending the useful life of the spring assembly while maintaining a compact design.
Solution Approach 2:
The design changes the load distribution parameter by introducing multiple laminations with the guide wall maintaining their proximity. This parameter change allows the system to carry the same total load with reduced individual lamination stress, thereby extending service life while keeping space requirements minimal.
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
Enhances space efficiency and safety by maintaining lamination proximity, ensuring consistent counterbalance force and extending the lifespan of the spring assembly, even under heavier loads.
Implementation Method 1
The guide system is based on rolling elements that can be bearing or bushing supported, to reduce friction present as the spring members move past the roller elements.
Implementation Method 2
a guide wall positioned along a straight section of spring members so as to exert a force along the straight section of the spring members. The force prevents the laminations of the spring members from separating
Data Source
AI summary
In one embodiment of the invention, a patient side-system is provided that includes a column with a rail and a counterbalance subsystem. The patient side-system may further include a braking subsystem. The counterbalance subsystem includes a spring assembly coupled at one end to the column with a spring member, and a housing movably coupled to the rail. The housing includes a drum to receive the spring member and a plurality of roller elements to guide a movement of the spring member winding or unwinding on the drum. If present, the braking subsystem includes a first pulley rotatably coupled to the column, a second pulley with a locking mechanism spaced apart from the first pulley and rotatably coupled to the column, and at least one brake cable wrapped around the first pulley and the second pulley with ends coupled to the housing. The locking mechanism can set a position of the housing along the column.