Rack-Mounted Leg Exercise Apparatus with Constant Load Arm

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Solution Overview

Problem

Existing leg exercise apparatuses for weight training are bulky, heavy, and difficult to move or disassemble, leading to inefficiencies in muscle training due to inconsistent load distribution and lack of versatility in exercise starting positions.

Innovation Solution

A leg exercise apparatus designed to be compact and easily installable on a rack, featuring a rotating arm with a support means that maintains a constant distance between the weight rod and the arm, ensuring consistent load distribution and allowing for adjustable exercise configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If independent gym machines with pulley systems are used, then load constancy and training effectiveness are improved, but device bulk and weight increase significantly

Engineering Contradiction:
Improveload constancyVSAvoiddevice weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent extracts the essential function of load application from the complex pulley system. Instead of using a full pulley mechanism, the invention uses a simple rod with weights that can be directly attached to the bar, keeping only the necessary weight loading function while removing the bulky pulley infrastructure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than having weights move through a pulley system to apply load, the invention inverts the approach by having weights remain stationary on the rod while the bar with the exercise mechanism moves, achieving load application without the intermediate pulley mechanism.

Inventive Principle:
Principle #13The other way round (Inversion)

2Device complexity

If disk load systems are used, then device simplicity is improved, but training effectiveness decreases due to dead points and inconsistent load curve

Engineering Contradiction:
Improvesystem simplicityVSAvoidload curve constancy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent positions the rod supporting weights in a specific spatial relationship to the bar - offset laterally and positioned at a distance that ensures the weight vector remains perpendicular to the bar throughout the exercise range of motion. This dimensional positioning eliminates dead points and maintains constant load.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention changes the critical parameter of weight position from being attached at the bar's rotation axis (creating dead points) to being positioned at a specific offset distance from the axis, which maintains perpendicular force application and eliminates load inconsistencies.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the bar starts from orthogonal rest position, then device structural simplicity is improved, but exercise safety and usability worsen due to lack of visual perception and awkward starting position

Engineering Contradiction:
Improvestarting position mechanismVSAvoidexercise safety
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent makes the rest position of the bar dynamic and adjustable rather than fixed at orthogonal position. The bar can be positioned at different angles including parallel to the ground, allowing users to select safe and comfortable starting positions visible to them during the exercise.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention allows users to preliminarily position the bar at the desired starting angle before beginning the exercise. This preliminary positioning ensures the bar starts in a safe, visible position rather than forcing users to begin from an awkward orthogonal position that may not be visible or safe.

Inventive Principle:
Principle #10Preliminary action

4Volume of moving object

If the rod is positioned close to the rotation fulcrum, then device compactness is improved, but load perception and training effectiveness decrease

Engineering Contradiction:
Improvedevice compactnessVSAvoidload perception
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

Instead of positioning the rod close to the fulcrum in the same plane, the invention positions the rod in a different spatial dimension - offset laterally from the bar's axis of rotation. This creates a moment arm that maintains effective load application while keeping the overall device compact.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 apparatus provides a more effective and versatile leg training experience by maintaining constant load throughout exercises, reducing dead points, and allowing for different exercise starting positions, thus enhancing muscle training efficacy and user safety.

Implementation Method 1

a first roller (10) extending away from the arm along a second direction (B), parallel to the hinge axis (X)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a rod (11) for supporting weights

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 3

The first end (9a) of the arm (9) is hinged to the fixing system (2) so as to be rotatable relative to a hinge axis (X)

Methodology Applied
Scientific EffectHinge: Hinge

Data Source

PatentEP4275767B1Leg exercise apparatus installable on an upright, for example of a rack, and exercise station comprising said apparatus
Publication Date: 2025.05.07 LACERTOSUS SRL
  • EP4275767B1 patent drawingFigure 1
  • EP4275767B1 patent drawingFigure 2~3
  • EP4275767B1 patent drawingFigure 4

AI summary

A leg exercise apparatus (1) installable on an upright (111), for example of a rack (110), said apparatus (1) comprising: a fixing system (2), installable on the upright (111); an arm (9) extending along a first direction (A) and hinged to the fixing system (2) so as to be rotatable relative to a hinge axis (X); a first push roller (10) mounted on one side of the arm (9); a support rod (11) for weights; a support means (12) for supporting the rod (11) at a first distance from the arm (9), said support means (12) being mounted on the arm (9).