Bicycle Frame Bottom Bracket Concealing Rear Fork Assembly

Solution Overview

Problem

Conventional bicycle frames with rear fork assemblies experience undesired wind resistance and aesthetic issues due to projecting fork ends, which affect their performance and appearance.

Innovation Solution

A bottom bracket device with a rear fork assembly that has its front end portion pivotably connected within a receiving space defined by side walls of a seat tube, reducing wind resistance and enhancing aesthetics by concealing the fork ends.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the front ends of the forks are disposed to project laterally and outwardly of the lower seat tube, then the rear fork assembly can be pivotably connected to the frame, but undesired wind resistance is produced and outer appearance is adversely affected

Engineering Contradiction:

Improvepivotability of rear fork assemblyVSAvoidwind resistance

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The rear fork assembly is nested within the lower seat tube structure. The front ends of the forks are received within the lower seat tube, with the fork ends positioned inside the tube's internal cavity. This nesting arrangement conceals the fork ends from external view, eliminating the aerodynamic drag caused by projecting fork ends while preserving the pivotable connection functionality through internally mounted pivot mechanisms.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of operation

If the front ends of the forks are disposed to project laterally and outwardly of the lower seat tube, then the rear fork assembly can be pivotably connected to the frame, but the outer appearance of the bicycle frame is adversely affected

Engineering Contradiction:

Improvepivotability of rear fork assemblyVSAvoidouter appearance of bicycle frame

Core Design Contradiction:

Ease of operationVSShape

Solution Approach 1:

The rear fork assembly is nested within the lower seat tube structure. The front ends of the forks are received within the lower seat tube, with the fork ends positioned inside the tube's internal cavity. This nesting arrangement conceals the fork ends from external view, eliminating the aerodynamic drag caused by projecting fork ends while preserving the pivotable connection functionality through internally mounted pivot mechanisms.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Object-affected harmful factors

If the rear fork assembly is integrated within the frame structure, then wind resistance is minimized and aesthetics are improved, but the fork ends must be concealed within the frame

Engineering Contradiction:

Improvewind resistanceVSAvoidintegration of rear fork assembly within frame

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The rear fork assembly is nested within the lower seat tube structure. The front ends of the forks are received within the lower seat tube, with the fork ends positioned inside the tube's internal cavity. This nesting arrangement conceals the fork ends from external view, eliminating the aerodynamic drag caused by projecting fork ends while preserving the pivotable connection functionality through internally mounted pivot mechanisms.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentEP3378752B1Bottom bracket device and a bicycle frame with the same

Publication Date: 2020.05.27 APROTECH

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AI summary

A bottom bracket device (10) includes a bottom bracket shell (11), and a first down tube (12) and a first seat tube (13) both connected to and extending from the bottom bracket shell (11). The first seat tube (13) defines therein a receiving space (131) with a rear access opening (132). A rear fork assembly (14) has a front end portion inserted from the opening (132) to be concealed in the space (131) and pivotably connected to the first seat tube (13). A bicycle frame (1) includes the above-mentioned bottom bracket device (10), a front frame body (20), a rear frame body (30) and a shock absorber (40).