The design and fabrication of a passive and continuously repositionable joint

A cam based locking mechanism was designed and fabricated to secure the joints of a continuously repositionable table capable of supporting a 11 IN load. Additionally, a frame was designed and built to test the feasibility of this joint concept as an assembly. Conventional toothed mechanisms were found to not provide a desirable smoothness of motion or resolution for implementation as an adjustable table. They also require more geometrically complex components than the proposed solution. The proposed mechanism relies on the binding of an eccentric cam and pulley, and is of interest because these key components are geometrically simple in comparison to toothed mechanisms. The reduced complexity of this solution is expected to lower the manufacturing cost of this type of joint and increase the resolution of its angular position, when compared to similar mechanisms. A model of the jamming interaction was evaluated using Matlab. This model was used to select the optimal material, eccentricity and diameter of the components. The elements were then fabricated with an Omax 2626 Precision JetMachining Center, and mechanically tested using calibrated weights. The fabricated joint is capable of holding a 56.5N*m load with a stiffness of 7.8N*m/degree.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2013

Author dc:creator

• Daniel, Phillip Howard

Advisor dc:contributor.advisor

• Alexander H. Slocum.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/83704

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/83704