Rotary damper

• US 4,691,811 A
• Filed: 02/19/1986
• Issued: 09/08/1987
• Est. Priority Date: 02/21/1985
• Status: Expired due to Term

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Nifco Incorporated
• Inventors: Numata, Masanori, Arakawa, Masaru
• Primary Examiner(s): Reger, Duane A.
• Assistant Examiner(s): Graham, Matthew C.
• Application Number:
  US06/831,430
• Time in Patent Office: 566 Days
• Field of Search: 188/29 D, 188/276, 277/96, 277/212 R, 192/58 R, 192/58 C
• US Class Current: 188/290
• CPC Class Codes: F16F 9/12 Devices with one or more rotary vanes turning in the fluid any throttling effect being immaterial, i.e. damping by viscous shear effect only F16F9/53 takes precedence; pivoting supports for apparatus or articles placed on stands or trestles F16M11/06
• CPC Class Codes: F16H 55/14 Construction providing resilience or vibration-damping F16H55/06 takes precedence

Abstract

A rotary damper comprises a cylindrical case closed at the bottom and having a housing containing a viscous liquid, a lid mounted in the case to close the housing and having a central circular hole, and a rotor having a shaft passing through the hole of the lid, a driven gear secured to its distal end and a brake plate rotatably disposed in the viscous liquid in the housing. The central circular hole has an increased diameter portion provided adjacent to the housing, and an O-ring is fitted on the shaft of the rotor and received in the increased diameter portion such that it is radially compressed by the peripheral wall of the increased diameter portion.

Claims

1. A rotary damper comprising:

a cylindrical case closed at the bottom and having a housing containing a viscous liquid;

a lid mounted in said case to close said housing and having a central circular hole; and

a rotor having a shaft passing through said hole of said lid, a driven gear secured to its distal end and a brake plate rotatably disposed in the viscous liquid in said housing;

said central circular hole having an increased diameter counterbore portion provided adjacent to said housing opening radially inwardly toward said shaft and axially toward said brake plate, and an O-ring being fitted on said shaft of said rotor and received in said increased diameter counterbore portion such that is axially abuts said lid in said counterbore portion and is radially compressed by the peripheral wall of said increased diameter portion and is exposed axially toward and thereby engages with said brake plate as well as said shaft.