Hydraulic buffer

Claim 2

A hydraulic buffer (20) comprising: a cylinder (22); a piston (24) disposed slidably in the cylinder (22) to partition the interior of the cylinder (22) into first and second liquid chambers (A,B); a piston rod (26) connected with the piston (24) and having a first path (36) communicating to the first liquid chamber (A) and extending axially and a second path (38,90) extending inward from an outer peripheral surface thereof; a control rod (42) disposed in the piston rod (26); a regulating valve (46,92) operated by the control rod (42), disposed in a position in the first path facing the second path of the piston rod and having a third path (50,94) capable of affording communication between the first and the second paths; a case (56,96) fixed to a position in the second liquid chamber (B) on an outer peripheral surface of said piston rod (26) and having a fourth path (56,98) affording communication between the second path (38,90) of the piston rod and the second liquid chamber (B); and a check valve (60,104) provided in association to the fourth path of said case for blocking liquid flow from the second liquid chamber (B) to the first liquid chamber (A) when the piston rod (26) extends and allowing the liquid to flow from the first liquid chamber (A) to the second liquid chamber (B) when the piston rod (26) contracts.

Claim 3

A hydraulic buffer as claimed in claim 1, wherein a fifth path (40,102) is provided in said piston rod (26) or said case (96) for allowing the liquid flow between the first and the second liquid chambers (A,B), and said regulating valve (46,92) is capable of regulating the effective area of said fifth path when the piston rod extends and contracts.

Claim 4

A hydraulic buffer as claimed in claim 2, wherein said third path (50) of the regulating valve (46) comprises a plurality of path portions having bores with different diameters, and said fifth path (40) is regulated in the same number of stages as that of the path portions of the third path (50).

Claim 5

A hydraulic buffer as claimed in claim 3, wherein said third path (50) consists of three path portions (51b,51c,51d).

Claim 6

A hydraulic buffer as claimed in claim 2, wherein said fifth path (40) is provided in a position of siad piston rod axially spaced from said second path (38) and extends inward from the outer peirpheral surface thereof, and said regulating valve (46) has a sixth path (52) capable of affording communication between the first and the fifth paths (36,40).

Claim 7

A hydraulic buffer as claimed in claim 5, wherein said third path (50) of the regulating valve (46) comprises a plurality of path portions having bores with different diameters, and said sixth path (52) comprises a plurality of path portions having bores with different diameters and being in the same path relation to the path portions of the third path (50) respectively.

Claim 8

A hydraulic buffer as claimed in claim 2, wherein said fifth path (102) is provided in said case (96), and the amount of the liquid flowing through the fifth path (102) is regulated by said third path (94) of the regulating valve (92).

Claim 9

A hydraulic buffer as claimed-in claim 1, wherein said regulating valve (46,92) is formed cylindrically and rotated by the control rod (42).

Claim 10

A hydraulic buffer as claimed in claim 1, wherein said fourth path (58,98) of the case (56,96) has a groove-like path portion (59c,100a,100b,100c) provided on the upper end of the case, and said check valve contacts the upper end of the case (56,96).

Claim 11

A hydraulic buffer as claimed in claim 9, wherein said check valve (60,104) is formed of an annular plate member.

Claim 12

A hydraulic buffer (20) comprising: a cylinder (22); a piston (24) disposed slidably in the cylinder (22) to partition the interior of the cylinder into first and second liquid chambers (A,B); a piston rod (26) connected with the piston and having a first path (36) communicating to the first liquid chamber (A) and extending axially and a second path (78) extending inward from the outer peripheral surface thereof; a control rod (42) disposed in the piston rod; a regulating valve (46) operated by the control rod (42), disposed in a position in the first path facing the second path of the piston rod and having a third path (50) capable of affording communication between the first and the second paths (36,78); a case (80) fixed to a position in the second liquid chamber (B) on the outer peripheral surface of said piston rod (26); and a check valve (82) disposed slidably on the outer peripheral surface of the piston rod (26) and being capable of closely contacting said case (80), wherein said check valve (82) blocks liquid flow from the second liquid chamber (B) to the first liquid chamber (A) when the piston rod (26) extends, and a fourth path is formed between the case (80) and the check valve (82) to afford communication between the second path (78) of the piston rod and the second liquid chamber (B) when the piston rod contracts so that the check valve (82) allows the liquid to flow from the first liquid chamber (A) to the second liquid chamber (B).

Claim 13

A hydraulic buffer (20) comprising: a cylinder (22); a piston (24) disposed slidably in the cylinder (22) to partition the interior of the cylinder into first and second liquid chambers (A,B); a piston rod (26) connected with the piston and having a first path (36) communicating to the first liquid chamber (A) and extending axially and a second path (78) extending inward from the outer peripheral surface thereof; a control rod (42) disposed in the piston rod; a regulating valve (46) operated by the control rod (42), disposed in a position in the first path facing the second path of the piston rod and having a third path (50) capable of affording communication between the first and the second paths (36,78); a case (80) fixed to a position in the second liquid chamber (B) on the outer peripheral surface of said piston rod (26); and a check valve (82) disposed slidably on the outer peripheral surface of the piston rod (26) and being capable of closely contacting said case (80), wherein said check valve (82) blocks liquid flow from the second liquid chamber (B) to the first liquid chamber (A) when the piston rod (26) extends, and a fourth path is formed between the case (80) and the check valve (82) to afford communication between the second path (78) of the piston rod and the second liquid chamber (B) when the piston rod contracts so that the check valve (82) allows the liquid to flow from the first liquid chamber (A) to the second liquid chamber (B).

Claim 14

A hydraulic buffer as claimed in claim 11, wherein a fifth path (40) is provided in a position of said piston rod (26) axially spaced from said second path (78) and extends inward from the outer peripheral surface thereof, and said regulating valve (46) has a sixth path (52) capable of affording communication between the first and the fifth paths (36,40).

Claim 15

A hydraulic buffer as claimed in claim 12, wherein said third path (50) of the regulating valve (46) compirses a plurality of path portions having bores with different diameters, and said sixth path (52) comprises a plurality of path portions having bores with different diameters and being in the same phase relation to the path portions of the third path (50) respectively.

Claim 16

A hydraulic buffer as claimed in claim 13, wherein said third path (50) and said sixth path (52) consists of three path portions (51b,51c,51d,53b,53c,53d) respectively.

Claim 17

A hydraulic buffer as claimed in claim 11, wherein said regulating valve (46) is formed cylindrically and rotated by the control rod (42).

Claim 18

A hydraulic buffer as claimed in claim 11, wherein said check valve (82) is formed of a cylindrical member and a recess is formed between the check valve (82) and the piston rod (26).