Damper

• US 20040032068A1
• Filed: 06/05/2003
• Published: 02/19/2004
• Est. Priority Date: 08/19/2002
• Status: Active Grant

• Current Assignee: Nifco Incorporated
• Original Assignee: Nifco Incorporated
• Inventors: Shibao, Masaharu
• Granted Patent: US 6,968,930 B2
• Time in Patent Office: Days
• US Class Current: 267/196
• CPC Class Codes: F16F 7/09 in dampers of the cylinder-and-piston type
• CPC Class Codes: F16F 9/3221 of piston rods
• CPC Class Codes: F16F 9/3235 of cylinders F16F9/483 takes precedence

Abstract

A damper includes a cylinder, and a piston rod inserted into the cylinder through an opening portion of the cylinder. The piston rod includes front and base ends, and a frictional engaging member provided on an outer surface along a longitudinal direction thereof extending from a front end side toward the base end. A resistance device is disposed at the opening portion of the cylinder. The resistance device contacts the frictional engaging member and deforms elastically to provide frictional resistance to the piston rod as the piston rod is withdrawn from the cylinder.

Claims

1. A damper, comprising:

a cylinder having an opening portion,

a piston rod inserted into the cylinder through the opening portion, and including front and base ends, and a frictional engaging member provided on an outer surface thereof along a longitudinal direction thereof extending from a front end side toward the base end, and

resistance means disposed at the opening portion of the cylinder, said resistance means contacting the frictional engaging member and deforming elastically to provide frictional resistance to the piston rod as the piston rod is withdrawn from the cylinder.

2. A damper according to claim 1, wherein said frictional engaging member is an inclining part provided on the piston rod along the longitudinal direction and having a height gradually increasing toward the base end.

3. A damper according to claim 2, wherein said resistance means is formed of a spring member with two spring portions bridging over the opening and sandwiching the inclining part.

4. A damper according to claim 3, wherein said piston rod is formed of a plate member with a plate surface, said inclining part projects from the plate surface of the plate member, and said cylinder includes a holding member for holding the spring member, said spring member having spring portions for receiving the inclining wall therebetween so that the inclining part is pushed by the spring portions to expand outwardly when the piston rod moves inside the cylinder.

5. A damper according to claim 4, wherein said holding member of the cylinder includes fixing holes formed in a peripheral wall of the cylinder for receiving the spring member therein.

6. A damper according to claim 2, further comprising a piston disposed at the base end of the piston rod for contacting an inner surface of the cylinder.

7. A damper according to claim 6, further comprising a sealing member, said piston including a circular groove around a periphery thereof for receiving the sealing member, and a step for forming a communication path between portions below and above the piston inside the cylinder.

8. A damper according to claim 2, further comprising a cover fitted to the opening portion of the cylinder and having a through-hole for receiving the piston rod therethrough, said resistance means including a pressure piece provided at a side of the through-hole for contacting the inclining part and a spring member attached to the cover for urging the pressure piece toward the inclining part.

9. A damper according to claim 8, wherein said piston rod and said pressure piece are formed of a synthetic resin.

10. A damper according to claim 8, wherein said pressure piece is formed of a plurality of pressure members facing each other.

11. A damper according to claim 1, wherein said frictional engaging member includes an elongated groove formed in the piston rod, and said resistance means is a spring having an end engaging the elongated groove for providing frictional resistance relative to the elongated groove.

12. A damper according to claim 11, wherein said elongated groove has a width gradually decreasing toward the base end of the piston rod.

13. A damper according to claim 11, wherein said elongated groove has a depth gradually decreasing toward the base end of the piston rod.