Removable Pulley Assembly with Hooked Stem and Spring Bias

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Solution Overview

Problem

Existing pulley assemblies in exercise machines like reformers are difficult to remove and reposition, requiring additional pulleys or extensive time, limiting flexibility in using alternative pulley locations.

Innovation Solution

A removable pulley assembly with a yoke, pulley wheel, and an elongated stem with a hook-shaped end and tapered coil spring, allowing attachment to any eyebolt or hook, enabling quick and secure fastening and detachment from various locations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pulley is bolted to upright member, then pulley is securely fastened, but pulley cannot be easily removed or repositioned

Engineering Contradiction:
Improvesecure fasteningVSAvoidremoval and repositioning
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The pulley assembly is divided into separable components: a removable pulley body and a stationary mounting structure. The pulley can be detached from the upright member by simply lifting it off the mounting bracket, eliminating the need for tools or complex disassembly procedures while maintaining secure operation during use.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mounting system transitions from a static bolted connection to a dynamic removable connection. The pulley is designed to be quickly attached and detached from the upright member through a simple lifting motion, allowing the system to adapt between fixed and mobile states as needed.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If additional pulleys are mounted on upright members, then more pulley locations are available, but device complexity increases

Engineering Contradiction:
Improvepulley location optionsVSAvoidnumber of pulleys
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The removable pulley assembly is designed with a universal mounting interface that can be used at multiple locations on the upright member. A single pulley can serve multiple functions by being relocated to different positions, eliminating the need for multiple dedicated pulleys and reducing overall system complexity.

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

3Reliability

If pulley is permanently fastened, then secure attachment is achieved, but time required for changing locations increases

Engineering Contradiction:
Improveattachment securityVSAvoidtime to change location
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The upright member is pre-equipped with mounting brackets at various locations before the pulley needs to be relocated. The pulley assembly is designed to quickly snap onto these pre-positioned brackets, eliminating the time-consuming process of drilling, bolting, or otherwise permanently fastening the pulley at each new location.

Inventive Principle:
Principle #10Preliminary action

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

Enables easy relocation and attachment of pulley assemblies to different eyebolt locations, enhancing exercise flexibility without the need for multiple pulleys or frequent restringing, allowing a variety of exercises to be performed efficiently.

Implementation Method 1

A tapered coil spring over the shaft portion of the stem has a small end wrapped onto the shaft portion and a large diameter around the shaft portion of the stem

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2442876B1Detachable pulley assembly
Publication Date: 2013.08.21 BALANCED BODY INC
  • EP2442876B1 patent drawingFigure 1
  • EP2442876B1 patent drawingFigure 2
  • EP2442876B1 patent drawingFigure 3

AI summary

A pulley assembly for removably fastening an arm cord to an exercise apparatus is disclosed. The pulley assembly includes a yoke having a central portion and a pair of parallel leg portions, the central portion having a bore therethrough, a pulley wheel rotatably supported between the yoke leg portions by an axle, and an elongated stem having an axially extending shaft portion protruding through the bore. The shaft portion has distal end portion having an L shaped slot formed therethrough. The L shaped slot forms a hook shaped end to the shaft portion. A tapered coil spring over the shaft portion of the stem, has a small end and a large diameter around the shaft portion of the stem. The spring biases the hooked end away from an eyebolt on the exercise apparatus to keep the pulley assembly engaged with the eye bolt and hence fastened to the exercise apparatus.