Suspension Caster Brake Lever Common Pivot Axis

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Solution Overview

Problem

Existing suspension casters face challenges in maintaining uniform braking force and accommodating varying wheel diameters while ensuring structural integrity and ease of manufacturing and assembly.

Innovation Solution

A suspension caster design featuring a yoke portion connected to a wheel fork assembly that pivots about a common axis, with a brake lever assembly that pivots about the same axis, utilizing a biasing member for shock absorption and a brake pad with adjustable mounting for different wheel diameters, allowing for simplified manufacturing and adaptable braking performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the brake lever pivots about a different axis than the yoke portion and wheel forks, then the braking mechanism can be structurally independent, but the overall device complexity increases and space requirements expand

Engineering Contradiction:
Improvebraking mechanism structureVSAvoidcaster assembly space
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The brake lever is configured to pivot about the same axis (pivot axis 46) as the yoke portion (22) and wheel forks (40), merging the braking mechanism's pivot point with the suspension mechanism's pivot point. This integration reduces the number of separate pivot axes and simplifies the overall structure while maintaining functional independence of the braking action.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The common pivot axis serves dual functions: it acts as the rotation axis for the yoke portion and wheel forks during normal suspension operation, and simultaneously serves as the pivot axis for the brake lever during braking. This multi-functional use of the pivot axis reduces device complexity without requiring additional dedicated pivot points.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If the brake pad mounting position is fixed, then the manufacturing precision can be maintained, but the adaptability to different wheel diameters is reduced

Engineering Contradiction:
Improvebrake pad mounting positionVSAvoidwheel diameter accommodation
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The brake pad (60) is mounted on the wheel forks (40) at a position that can be adjusted along the length of the wheel forks. This dynamic positioning capability allows the brake pad to be repositioned to accommodate different wheel diameters while maintaining precise mounting through controlled adjustment mechanisms, rather than having a fixed immutable position.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mounting position parameter of the brake pad can be changed to suit different wheel diameters. By allowing the brake pad's longitudinal position on the wheel forks to be varied, the system adapts to different wheel sizes while maintaining manufacturing precision through defined adjustment ranges and mounting interfaces.

Inventive Principle:
Principle #35Parameter changes

3Force

If the brake lever is positioned far from the pivot axis, then the braking torque is increased, but the device complexity and space requirements increase

Engineering Contradiction:
Improvebraking torqueVSAvoidbrake lever assembly structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The brake lever pivots about the same axis as the yoke portion and wheel forks, merging the braking function into the existing suspension structure. This integration allows the brake lever to extend from the common pivot axis without requiring separate mounting structures, thereby increasing braking torque through optimal lever arm length while avoiding additional structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 ensures uniform braking force across varying loads and wheel positions, accommodates different wheel diameters, and provides a compact and stable braking function, enhancing manufacturing simplicity and flexibility.

Implementation Method 1

a biasing member, such as a spring, between the yoke portion and the wheel forks

Methodology Applied
Scientific EffectShock absorption: Damping

Implementation Method 2

a biasing member, such as a spring, between the yoke portion and the wheel forks

Methodology Applied
Scientific EffectSpring elastic force: Spring

Implementation Method 3

a brake pad positioned to engage the wheel when the brake lever is actuated

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3638514B1Suspension caster with brake lever and wheel fork and yoke portion having common pivot axis
Publication Date: 2022.07.20 COLSON GROUP HOLDINGS LLC
  • EP3638514B1 patent drawingFigure 1~2
  • EP3638514B1 patent drawingFigure 3~5
  • EP3638514B1 patent drawingFigure 6~7

AI summary

A caster has a yoke portion and wheel forks pivotally connected to the yoke portion at a pivot connection. The pivot connection defines a pivot axis. A wheel is rotatably connected to the wheel fork at a wheel axis. A brake lever is operatively connected to the pivot connection to pivot about the pivot axis. The brake lever moves a brake pad between an engaged position and a disengaged position as the brake lever is pivoted about the pivot axis. In the engaged position, brake pad is pressed against the wheel with a cam operatively connected to the brake lever, and wherein the disengaged position, the cam cooperates with the brake pad in a manner such that the brake pad releases from the wheel.