Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Moving Platform Suspension

IP.com Disclosure Number: IPCOM000044600D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Hollis, RL: AUTHOR

Abstract

Using U-shaped spring wire supports, or coaxial spring rod-in-tube supports, permits X-Y-r movement of a moving platform without Z-motion. It is often desirable in a limited-motion positioning stage to limit the number of degrees of freedom to only those desired. Thus, for example, in a conventional motor-driven translation stage or platform, sliding ways, ball bearings, or crossed roller bearings are often used to restrict motion to a single degree of freedom. Such constraint methods often suffer from friction, wear, and alignment problems in mechanisms where extremely precise operation is required. For mechanisms limited to small translational motion, parallelogram spring flexures or colonnade flexures are often used, eliminating sliding parts.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 2

Moving Platform Suspension

Using U-shaped spring wire supports, or coaxial spring rod-in-tube supports, permits X-Y-r movement of a moving platform without Z-motion. It is often desirable in a limited-motion positioning stage to limit the number of degrees of freedom to only those desired. Thus, for example, in a conventional motor-driven translation stage or platform, sliding ways, ball bearings, or crossed roller bearings are often used to restrict motion to a single degree of freedom. Such constraint methods often suffer from friction, wear, and alignment problems in mechanisms where extremely precise operation is required. For mechanisms limited to small translational motion, parallelogram spring flexures or colonnade flexures are often used, eliminating sliding parts. These flexure supports or colonnade supports are elegant means of providing frictionless suspensions, providing two and three degrees of freedom, respectively. The suspended platform moves with precision in a parallel manner, but a slight out-of-plane motion is imparted to the platform at its extremes of motion, due to the slight change in projected length of the flexed springs or columns. The problem is made worse in the three-degree-of-freedom case because there is additional out- of-plane deflection caused by rotation. Fig. 1 shows this suspension, which solves the out-of-plane deflection problem yet permits two translational degrees of freedom and one rotational degree of freedom, by using U-shaped or wishbone-shaped wire supports. The moving platform 1 is supported by three or more U-shaped wires 2, made of spring material, from fixed base 3. As the platform is deflected or rotated, it remains strictly in its plane because the change in projected length of one arm of the U-shaped wire is compensated for by the change in projected length of the other arm of the U-shaped wire; i.e., as one arm tends t...