Rotary damper with improved connection between cap and housing

• US 5,269,397 A
• Filed: 03/10/1992
• Issued: 12/14/1993
• Est. Priority Date: 03/11/1991
• Status: Expired due to Term

• Current Assignee: Nifco Incorporated
• Original Assignee: Nifco Incorporated
• Inventors: Tokahashi, Norio, Yamaguchi, Keiji, Kawamoto, Masanobu
• Primary Examiner(s): Oberleitner, Robert J.
• Assistant Examiner(s): BALLATO, JOSIE
• Application Number:
  US07/848,182
• Time in Patent Office: 644 Days
• Field of Search: 188/293, 188/296, 188/290, 188/306, 188/322.5, 74/574, 16/82, 16/85, 16/DIG. 9,DIG. 10, 192/58 B, 192/112
• US Class Current: 188/290
• CPC Class Codes: B29C 65/08 using ultrasonic vibrations non-plastics element to plastics elements B29C65/645
• CPC Class Codes: B29C 66/12449 being asymmetric B29C66/12445 takes precedence
• CPC Class Codes: B29C 66/12463 being tapered
• CPC Class Codes: B29C 66/12469 being asymmetric
• CPC Class Codes: B29C 66/24221 being circular B29C66/51 takes precedence
• CPC Class Codes: B29C 66/30223 said melt initiators being rib-like
• CPC Class Codes: B29C 66/322 Providing cavities in the joined article to collect the burr
• CPC Class Codes: B29C 66/543 joining more than two hollow-preforms to form said hollow articles
• CPC Class Codes: B29C 66/55 sealing elements being incorporated into the joints, e.g. gaskets B29C66/52296 takes precedence
• CPC Class Codes: B29C 66/8322 Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29L 2031/721 Vibration dampening equipment, e.g. shock absorbers bumpers B29L2031/3044, springs B29L2031/774
• 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: F16F 9/3242 of cylinder ends, e.g. caps

Abstract

A rotary damper includes a dish-shaped housing having a depression surrounded by a cylindrical wall, a viscous fluid contained in the depression, a damping rotor accommodated in the viscous fluid, and a cap covering the dish-shaped housing with a shaft of the damping rotor projecting through a central hole thereof. The cylindrical wall is provided at the base of its external periphery with a sloped annular portion of downward increasing diameter. A lower edge portion of a circular wall of the cap is contacted with the slope of the sloped annular portion during welding of the cap to the dish-shaped housing.

Claims

1. A rotary damper comprising:

a damping rotor having a central revolving shaft;

a dish-shaped housing having a bottom wall and a cylindrical wall to define a round depression being filled with viscous fluid, and a sloped annular portion with a diameter increasing downward provided at an external periphery of a lower edge of said cylindrical wall, said damping rotor being rotatably accommodated in said round depression filled with the viscous fluid; and

a cap having a central hole for passage of said revolving shaft of said damping rotor, an inner bottom provided with a downwardly directed annular thick portion with a diameter smaller than an inner diameter of said cylindrical wall of said dish-shaped housing and forming a gap in cooperation with said cylindrical wall of said dish-shaped housing, and a circular wall provided along an external periphery thereof for being fitted on the external periphery of said cylindrical wall of said dish-shaped housing;

said circular wall of said cap having a lower edge with an internal periphery brought into contact from above with a slope of said sloped annular portion of said dish-shaped housing for welding said cap so as to cover said round depression from above and define an annular space between an external periphery of said annular thick portion of said cap and an internal periphery of said cylindrical wall of said dish-shaped housing.