Piston unit

• US 4,342,884 A
• Filed: 06/11/1979
• Issued: 08/03/1982
• Est. Priority Date: 06/14/1978
• Status: Expired due to Term

• Current Assignee: Hidenori Kanno, Itsuki Ban
• Original Assignee: Hidenori Kanno, Itsuki Ban
• Inventors: Kanno, Hidenori, Ban, Itsuki
• Primary Examiner(s): WITKOWSKI, STANLEY J
• Application Number:
  US06/047,047
• Time in Patent Office: 1,149 Days
• Field of Search: 200/34, 200/83 R, 200/83 A, 200/83 B, 200/83 D, 200/83 J, 200/83 Q, 200/83 T, 267/114, 267/122, 267/123, 267/124, 267/8 R, 188/282, 188/297, 188/298, 188/311-313, 188/316, 188/322.17, 74/18.2
• US Class Current: 200/34
• CPC Class Codes: F16F 13/00 Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs F16F5/00, F16F6/00, F16F9/003 take precedence
• CPC Class Codes: F16F 2230/10 Enclosure elements, e.g. for protection
• CPC Class Codes: F16F 9/16 involving only straight-line movement of the effective parts wing closers or openers with liquid piston brakes E05F3/04
• CPC Class Codes: F16F 9/20 with the piston-rod extending through both ends of the cylinder , e.g. constant-volume dampers
• CPC Class Codes: F16F 9/34 Special valve constructions F16F9/44, F16F9/50 take precedence; filtering details F16F9/3285 ; valves in general F16K; Shape or construction of throttling passages
• CPC Class Codes: F16F 9/361 Sealings of the bellows-type
• CPC Class Codes: F16F 9/516 resulting in the damping effects during contraction being different from the damping effects during extension , i.e. responsive to the direction of movement F16F9/504 takes precedence
• CPC Class Codes: H01H 13/24 with means for introducing a predetermined time delay

Abstract

A small-sized differential piston unit is disclosed. The piston unit has a cylinder filled with liquid medium and a piston slideably mounted in the cylinder. An operation rod is operatively connected to said piston. An improved sealing member consisting of a membrane is used to completely seal the liquid medium in the cylinder. Control means is provided for imparting fluid resistance caused by the liquid medium to the piston differently between its forward movement and backward movement in the cylinder.

Claims

1. A piston unit comprising:

cylinder means having a pair of opposed axial ends and substantially filled with liquid medium;

piston means slidably mounted in said cylinder means;

spring means for urging said piston means toward one axial end of said cylinder means;

an operation rod having one end portion coupled to said piston means so as to be movable therewith and a shank portion extending to the outside of said cylinder means;

sealing means for sealing said liquid medium in said cylinder means, said sealing means including a flexible membrane having a central portion fixedly interposed between said one end portion of said operation rod and said piston means and a corrugated portion integrally extending from said central portion, said corrugated portion having a peripheral edge region liquid sealingly engaged with said cylinder means such that said membrane seals said liquid medium in said cylinder means and defines a space within the cylinder means which is devoid of the liquid medium, said operation rod being situated in said space fluidly isolated from and not in contact with said liquid medium; and

control means for providing that fluid resistance presented by said liquid medium to movement of said piston means toward one of said ends of said cylinder means is different from the fluid resistance presented by said liquid medium to movement of said piston means toward the other one of said ends of said cylinder means, said control means including a through bore formed in said piston means and a valve member coupled to said piston means adapted to open and close said through bore, said valve member being plate-shaped and having a small bore therein situated in substantially opposed relationship to said through bore.

2. A piston unit as claimed in claim 1, wherein said liquid medium is silicon oil.

3. A piston unit as claimed in claim 1, wherein said liquid medium is a mixture of ethylene glycol and water.

4. A piston unit as claimed in claim 1, wherein said membrane is made of synthetic rubber.

5. A piston unit as claimed in claim 1, wherein said spring means includes a coiled spring disposed between the inner end of said cylinder means and said piston means.

6. A piston unit as claimed in claim 1, wherein said spring means includes a coiled spring disposed between the outer end of said cylinder means and said operation rod.

7. A piston unit as claimed in claim 1, wherein said spring means comprises a membrane having a regularly corrugated portion.

8. A piston unit as claimed in claim 1, wherein said central portion of said membrane comprises a hardened portion which is fitted firmly to said piston means, and wherein said corrugated portion extends continuously from said hardened central portion.

9. A piston unit as claimed in claim 1, wherein said central portion of said membrane includes a thick-walled portion at which said membrane is fitted firmly to said piston means, said corrugated portion being integrally connected to said thick-walled portion and wherein said peripheral edge region of said corrugated portion has a bead formed thereon, said bead being fixed liquid-tightly to said cylinder means.

10. A piston unit comprising:

cylinder means having a pair of opposed axial ends and including a switch member and a switch actuating member for actuating said switch member, said cylinder means being substantially filled with liquid medium;

piston means slidably mounted in said cylinder means, said switch actuating member being operatively connected to said piston means;

spring means for urging said piston means toward one axial end of said cylinder means;

an operation rod having one end portion coupled to said piston means so as to be movable therewith and a shank portion extending to the outside of said cylinder means;

sealing means for sealing said liquid medium in said cylinder means, said sealing means including a flexible membrane having a central portion fixedly interposed between said one end portion of said operation rod and said piston means and a corrugated portion integrally extending from said central portion, said corrugated portion having a peripheral edge region liquid sealingly engaged with said cylinder means such that said membrane seals said liquid medium in said cylinder means and defines a space within the cylinder means which is devoid of the liquid medium, said operation rod being situated in said space fluidly isolated from and not in contact with said liquid medium; and

control means for providing that fluid resistance presented by said liquid medium to movement of said piston means toward one of said ends of said cylinder means is different from the fluid resistance presented by said liquid medium to movement of said piston means toward the other one of said ends of said cylinder means, said control means including a through bore formed in said piston means and a valve member coupled to said piston means adapted to open and close said through bore.

11. A piston unit as claimed in claim 10, wherein said piston means include a coiled spring adapted for urging said switch actuating member toward said switch member.

12. A piston unit as claimed in claim 10, wherein said spring means is interposed between said piston means and said switch actuating member and wherein said switch actuating member is constituted by a piston adapted to be displaced slideably in said cylinder means and operatively connected to said piston means by means of said spring means.

13. A piston unit comprising:

cylinder means having a pair of opposed axial ends and including a cylinder cap attached thereto, a switch member disposed on said cylinder cap and a switch actuating member adapted to actuate said switch member, said cylinder means being substantially filled with liquid medium;

piston means slidably mounted in said cylinder means;

spring means for urging said piston means toward one axial end of said cylinder means;

an operation rod having one end portion coupled to said piston means so as to be movable therewith and a shank portion extending to the outside of said cylinder means, said switch actuating member of said cylinder means being operatively connected to said operation rod;

sealing means for sealing said liquid medium in said cylinder means, said sealing means including a flexible membrane having a central portion fixedly interposed between said one end portion of said operation rod and said piston means and a corrugated portion integrally extending from said central portion, said corrugated portion having a peripheral edge region liquid sealingly engaged with said cylinder means such that said membrane seals said liquid medium in said cylinder means and defines a space within the cylinder means which is devoid of the liquid medium, said operation rod being situated in said space fluidly isolated from and not in contact with said liquid medium; and

control means for providing that fluid resistance presented by said liquid medium to movement of said piston means toward one of said ends of said cylinder means is different from the fluid resistance presented by said liquid medium to movement of said piston means toward the other one of said ends of said cylinder means, said control means including a through bore formed in said piston means and a valve member coupled to said piston means adapted to open and close said through bore.

14. A piston unit comprising:

cylinder means having a pair of opposed axial ends and substantially filled with liquid medium;

piston means slidably mounted in said cylinder means;

spring means for urging said piston means toward one axial end of said cylinder means;

an operation rod having one end portion coupled to said piston means so as to be movable therewith and a shank portion extending to the outside of said cylinder means;

sealing means for sealing said liquid medium in said cylinder means, said sealing means including a flexible membrane having a central portion fixedly interposed between said one end portion of aid operation rod and said piston means and a corrugated portion integrally extending from said central portion, said corrugated portion having a peripheral edge region liquid sealingly engaged with said cylinder means such that said membrane seals said liquid medium in said cylinder means and defines a space within the cylinder means which is devoid of the liquid medium, said operation rod being situated in said space fluidly isolated from and not in contact with said liquid medium; and

control means for providing that fluid resistance presented by said liquid medium to movement of said piston means toward one of said ends of said cylinder means is different from the fluid resistance presented by said liquid medium to movement of said piston means toward the other one of said ends of said cylinder means, said control means including a through bore formed in said piston means and a valve member coupled to said piston means adapted to open and close said through bore, said valve member including a plate located in opposed relationship to said through-bore, said plate being formed of a mesh or network-like material.

15. A piston unit comprising:

cylinder means having a pair of opposed axial ends and substantially filled with liquid medium;

piston means slidably mounted in said cylinder means;

spring means for urging said piston means toward one axial end of cylinder means;

an operation rod having one end portion coupled to said piston means so as to be movable therewith and a shank portion extending to the outside of said cylinder means;

sealing means for sealing said liquid medium in said cylinder means, said sealing means including a flexible membrane having a central portion fixedly interposed between said one end portion of said operation rod and said piston means and a corrugated portion integrally extending from said central portion, said corrugated portion having a peripheral edge region liquid sealingly engaged with said cylinder means such that said membrane seals said liquid medium in said cylinder means and defines a space within the cylinder means which is devoid of the liquid medium, said operation rod being situated in said space fluidly isolated from and not in contact with said liquid medium; and

control means for providing that fluid resistance presented by said liquid medium to movement of said piston means toward one of said ends of said cylinder means is different from the fluid resistance presented by said liquid medium to movement of said piston means toward the other one of said ends of said cylinder means, said control means including a through bore formed in said piston means and a valve member coupled to said piston means adapted to open and close said through bore, said valve member including a plate having slits formed therein, said slits being located in opposed relationship to said through bore formed on said piston means.

16. A piston unit comprising:

cylinder means having a pair of opposed axial ends and substantially filled with liquid medium;

piston means slidably mounted in said cylinder means;

spring means for urging said piston means toward one axial end of said cylinder means;

an operation rod having one end portion coupled to said piston means so as to be movable therewith and a shank portion extending to the outside of said cylinder means;

sealing means for sealing said liquid medium in said cylinder means, said sealing means including a flexible membrane having a central portion fixedly interposed between said one end portion of said operation rod and said piston means and a corrugated portion integrally extending from said central portion, said corrugated portion having a peripheral edge region liquid sealingly engaged with said cylinder means such that said membrane seals said liquid medium in said cylinder means and defines a space within the cylinder means which is devoid of the liquid medium, said operation rod being situated in said space fluidly isolated from and not in contact with said liquid medium; and

control means for providing that fluid resistance presented by said liquid medium to movement of said piston means toward one of said ends of said cylinder means is different from the fluid resistance presented by said liquid medium to movement of said piston means toward the other one of said ends of said cylinder means, said control means including a through bore formed in said piston means and a valve member coupled to said piston means adapted to open and close said through bore, said valve member including a plate provided with a small bore located in opposed relationship to said through bore, and a bimetallic member having one end fixed to said plate and a closure member fixed to the other end of said bimetallic member adapted to selectively open and close said small bore.

17. A piston unit comprising:

cylinder means having a pair of opposed axial ends and substantially filled with liquid medium;

piston means slidably mounted in said cylinder means including a bimetallic member fixed at one of its ends thereto and a small plate attached to the free end of said bimetallic member;

spring means for urging said piston means toward one axial end of said cylinder means;

an operation rod having one end portion coupled to said piston means so as to be movable therewith and a shank portion extending to the outside of said cylinder means;

sealing means for sealing said liquid medium in said cylinder means, said sealing means including a flexible membrane having a central portion fixedly interposed between said one end portion of said operation rod and said piston means and a corrugated portion integrally extending from said central portion, said corrugated portion having a peripheral edge region liquid sealingly engaged with said cylinder means such that said membrane seals said liquid medium in said cylinder means and defines a space within the cylinder means which is devoid of the liquid medium, said operation rod being situated in said space fluidly isolated from and not in contact with said liquid medium; and

control means for providing that fluid resistance presented by said liquid medium to movement of said piston means toward one of said end of said cylinder means is different from the fluid resistance presented by said liquid medium to movement of said piston means toward the other one of said ends of said cylinder means, said control means including a through bore formed in said piston means and a valve member coupled to said piston means adapted to open and close said through bore and wherein the opening and closing of said through bore is controlled by said small plate which in turn is operated by said bimetallic member.

18. A piston unit comprising:

cylinder means having a pair of opposed axial ends and substantially filled with liquid medium;

piston means slidably mounted in said cylinder means;

spring means for urging said piston means toward one axial end of said cylinder means;

an operation rod having one end portion coupled to said piston means so as to be movable therewith and a shank portion extending to the outside of said cylinder means;

sealing means for sealing said liquid medium in said cylinder means, said sealing means including a flexible membrane having a central portion fixedly interposed between said one end portion of said operation rod and said piston means and a corrugated portion integrally extending from said central portion, said corrugated portion having a peripheral edge region liquid sealingly engaged with said cylinder means such that said membrane seals said liquid medium in said cylinder means and defines a space within the cylinder means which is devoid of the liquid medium, said operation rod being situated in said space fluidly isolated from and not in contact with said liquid medium; and

control means for providing that fluid resistance presented by said liquid medium to movement of said piston means toward one of said ends of said cylinder means is different from the fluid resistance presented by said liquid medium to movement of said piston means toward the other one of said ends of said cylinder means, said control means including a through bore formed in said piston means and a valve member coupled to said piston means adapted to open and close said through bore, said valve member being plate shaped and fixed at one end to said piston means.