Segmented Brake Ring for Spherical Wheel Stability
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Solution Overview
Problem
Existing wheel systems with spherical wheels face instability due to backlash and play in components, leading to unintended motion of carried loads, which is particularly dangerous in medical procedures where stability is critical.
Innovation Solution
A brake mechanism for spherical wheels that includes a base coupled to the wheel via a rotary bearing and a brake ring that selectively engages and disengages to provide controlled friction, preventing rotation and maintaining stability by constraining the wheel's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional brakepads are used in wheel systems, then the wheel system can be locked stationary, but backlash and play in components allow unintended motion and vibration of the carried load
Solution Approach 1:
The brake ring is segmented into multiple independent friction contact points around the spherical wheel's circumference. Each segment independently contacts the wheel surface, distributing the braking force and eliminating the single-point backlash issue. This segmentation allows the brake to engage multiple zones simultaneously, preventing rotational play while maintaining stability.
Solution Approach 2:
The brake mechanism transitions from traditional linear brakepad contact to a circumferential distribution of friction points around the spherical wheel. By arranging friction contacts in a circular pattern around the wheel's equator, the system adds a dimensional aspect that constrains motion in multiple directions simultaneously, eliminating backlash through geometric distribution rather than single-point forcing.
2Reliability
If additional stability mechanisms such as retractable feet are added to the wheel system, then stability during stationary operation is improved, but the cost and complexity of the wheel system increases
Solution Approach 1:
The brake ring serves multiple functions simultaneously: it provides friction-based rotational locking, acts as a structural constraint against lateral movement, and distributes load across multiple contact points. This multi-functionality eliminates the need for separate stability mechanisms like retractable feet, as the brake ring itself becomes the primary stability element for both rotational and lateral constraints.
Solution Approach 2:
The invention merges the braking function with the stability function into a single integrated brake ring structure. Rather than having separate components for locking the wheel and preventing lateral movement, the circumferential friction contacts perform both functions simultaneously, reducing overall system complexity while maintaining or improving stability performance.
3Force
If heavy loads are supported by the wheel system, then the carrying capacity is increased, but brakepads may slide and allow wheel motion
Solution Approach 1:
The brake ring divides the braking force into multiple discrete contact segments around the spherical wheel. Each segment independently bears a portion of the load-induced braking force, preventing any single contact point from sliding under heavy load. The distributed segmentation ensures that even if one contact point experiences slip, others maintain the braking constraint.
Solution Approach 2:
The system changes the parameter of friction contact from a single concentrated point to multiple distributed points around the wheel's circumference. This parameter change increases the total frictional resistance to sliding by distributing the normal force across multiple contacts, thereby maintaining brake holding stability even when supporting heavy loads that would cause single-point brakepads to slide.
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 brake mechanism ensures stable and secure locking of the wheel system, reducing backlash and unintended motion, thereby enhancing the stability of carried loads, especially in applications requiring precise positioning like teleoperated surgical devices.
Implementation Method 1
the brake ring provides friction opposing rotation of the spherical wheel when engaged
Data Source
AI summary
Implementations relate to a brake mechanism for a spherical wheel. In some implementations, a wheel mechanism includes a spherical wheel and a base coupled to the spherical wheel via a rotary bearing contacting a surface of the spherical wheel, where the rotary bearing is configured to allow the spherical wheel to rotate. The wheel mechanism includes a brake ring coupled to the base and configured to selectively engage and disengage the surface of the spherical wheel, where the brake ring provides friction opposing rotation of the spherical wheel when engaged.