Dual Cam Exercise Device for Multi-Joint Resistance
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Solution Overview
Problem
Existing exercise equipment is inadequate for effectively working muscle groups that cross multiple joints, as it does not provide resistance through the full range of motion, limiting muscle growth, rehabilitation, and conditioning.
Innovation Solution
A dual cam exercise apparatus that allows for movement of two joints through their full range of motion under resistance, using a secondary cam that moves around a fixed primary cam, with a connecting mechanism like a belt or chain, to provide continuous resistance from full extension to full contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If existing exercise equipment is used, then the device structure is simple, but it cannot provide resistance through the full range of motion for muscles crossing multiple joints
Solution Approach 1:
The exercise device is segmented into two independent cam mechanisms: a primary cam that moves linearly along a guide rail, and a secondary cam that rotates around the primary cam. This segmentation allows each cam to independently control one joint's range of motion, enabling comprehensive coverage of multi-joint muscle groups while maintaining modular device architecture
Solution Approach 2:
The mechanism transitions from one-dimensional linear motion to two-dimensional motion by having the secondary cam rotate around the primary cam's path. This dimensional change enables the system to simultaneously control flexion/extension of two different joints (e.g., shoulder and elbow), providing full range of motion coverage for bi-articular muscles
2Reliability
If a dual cam mechanism is implemented, then full range of motion resistance is achieved, but the device complexity increases
Solution Approach 1:
The dual cam mechanism is designed as a universal system that can exercise any bi-articular muscle group by adjusting the cam profiles and resistance application points. The same basic mechanism structure can target different muscle groups (biceps, triceps, quadriceps, hamstrings) through configuration changes rather than requiring separate specialized equipment for each muscle group
Solution Approach 2:
A connecting means (belt, chain, or cable) acts as an intermediary between the primary and secondary cams, transferring force and coordinating their motion. This intermediary element simplifies the mechanical connection between the two cams, reducing the complexity of direct mechanical coupling while ensuring synchronized movement through the full range of motion
Data Source
AI summary
A device for resistance exercise of muscle groups that cross two or more joints such as biceps group, triceps group, quadriceps group, and hamstring group. The device comprises a primary cam or gear fixed non-rotatably to the frame of an appropriate exercise machine for working the desired body part, and a secondary cam or gear connected only to the primary cam in such a way which, when rotated, tracks around the primary cam or gear. Resistance is provided with a cable, belt, chain, or other means to the axis of the secondary cam only. When properly positioned user applies force to the contact point connected to the secondary cam and secondary axis, the device moves both desired joints simultaneously through a range of motion while under a predictable resistance. The device provides an improved range of movement while under resistance, thereby supplying a greater extension and contraction of the desired muscle or muscle group than prior art devices.