In this rod-seal-free hydraulic damper, varying the slot cross section along the length of the operating rod could provide position-dependent flow resistance.
James Ranz of Wilmington, OH sent in this design concept that replaces the rod seal, and associated fluid leaks in hydraulic dampers, with two rolling diaphragms.
A separator disk, with a central hole supporting the operating rod, divides the volumes. Longitudinal grooves or flats on the operating rod control the damper's resistance.
In operation, the rod's movement compresses the volume of one rolling diaphragm and enlarges the other while passing oil through the orifice. Because the rod passes through the center of the diaphragms, which are sealed at points where there is no need for sliding motion, only air passes out of the external cylinder through vents. For more on rolling diaphragms contact:
Paul Chevalier, DIA-COM Corp., 5 Howe Dr., Amherst, NH 03031; Tel: (603) 880-1900 ext. 304; Fax: (603) 880-7616; E-mail: firstname.lastname@example.org.
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Submit your ideas and rough drawings for this section to John Lewis, Designer's Corner, Design News, 275 Washington St., Newton, MA 02458