Safety installation for two-circuit brake systems, especially of motor vehicles

Claim 2

A safety installation for two-circuit brake systems, especially of motor vehicles, in which two brake circuit means independent of one another, of which each brake circuit means includes its own line system and independent wheel brake cylinders, is supplied with pressure fluid by a master brake cylinder means, characterized by a closure means common to both brake circuit means and connected in the output of the master brake cylinder means, said closure means including control means operable in case of pressure loss in one brake circuit means to automatically close the pressure medium supply into said one inoperable brake circuit means by the pressure which builds up during actuation of the brake system in the other operable brake circuit means, characterized in that in the normal condition of the brake system with two operable brake circuit means, each brake circuit means is separated from the master brake cylinder means by the closure means and is connected with a respective pressure medium tank by way of a corresponding return line.

Claim 3

A safety installation according to claim 1, characterized in that the master brake cylinder means is constructed as tandem cylinder equipped with two master brake pistons movable with respect to each other.

Claim 4

A safety installation according to claim 1, characterized in that during the actuation of the brake system with two operable brake circuit means, each brake circuit means is connected with the master brake cylinder means by means of the closure means while the return lines are closed thereby.

Claim 5

A safety installation according to claim 3, characterized in that the closing and opening of the return lines takes place by displacement of two shifting piston means forming part of the control means.

Claim 6

A safety installation according to claim 4, characterized in that each operable brake circuit means is connected with the master brake cylinder means by way of a twin piston means common to both brake circuit means and forming part of the control means.

Claim 7

A safety installation according to claim 5, characterized in that the closing off of the inoperable brake circuit means takes place by displacement of the twin piston means common to both brake circuit means and forming part of the control means.

Claim 8

A safety installation according to claim 6, characterized in that the twin piston means is retained in its respective position by a detent means.

Claim 9

A safety installation according to claim 7, characterized in that the detent means includes a contact switch which is actuated by displacement of the twin piston means and which indicates the closing off of the inoperable brake circuit means by the closing of an electric circuit means for a warning device.

Claim 10

A safety installation according to claim 8, characterized in that the warning device includes an optical warning device.

Claim 11

A safety installation according to claim 9, characterized in that the warning device includes an acoustic warning device.

Claim 12

A safety installation according to claim 8, characterized in that the contact switch is included in the detent means.

Claim 13

A safety installation according to claim 11, characterized in that the closing means includes a housing provided with a cylinder bore, two inlet bores, two outlet bores and four return bores terminating in said cylinder bore, the twin piston means adjoined by the two shifting piston means being retained floatingly in a center position by means of two compression springs and the elastic detent means when the two brake circuit means are operable.

Claim 14

A safety installation according to claim 11, characterized in that in case of pressure loss in a brake circuit means, the operating pressure of the other operable brake circuit means which builds up displaces the twin piston means as well as the shifting piston means.

Claim 15

A safety installation according to claim 13, characterized in that the twin piston means during its displacement forces two detent pin means of the detent means out of a detent groove into the housing and in that a detent pin closes thereat a contact switch actuating a warning lamp.

Claim 16

A safety installation according to claim 14, characterized in that the displaced twin piston means closes off the inoperable brake circuit means and the displaced shifting piston means close off two return lines.

Claim 17

A safety installation according to claim 15, characterized in that the twin piston means as well as the shifting piston means of an inoperable brake circuit means are kept in the closing position by the re-engagement of the detent pins in a further adjacent detent groove of the twin piston means.

Claim 18

A safety installation according to claim 16, characterized in that the shifting piston means of an operable brake circuit means after termination of the braking operation again keeps closed the outlet bore of an operable brake circuit means under the pressure of the coordinated compression spring and again keeps open the return line.

Claim 19

A safety installation according to claim 1, characterized in that the closing and opening of the return lines takes place by displacement of two shifting piston means forming part of the control means.

Claim 20

A safety installation for two-circuit brake systems, especially of motor vehicles, in which two brake circuit means independent of one another, of which each brake circuit means includes its own line system and independent wheel brake cylinders, is supplied with pressure fluid by a master brake cylinder means, characterized by a closure means common to both brake circuit means and connected in the Output of the master brake cylinder means, said closure means including control means operable in case of pressure loss in one brake circuit means to automatically close the pressure medium supply into said one inoperable brake circuit means by the pressure which builds up during actuation of the brake system in the other operable brake circuit means, characterized in that the closing means includes a housing provided with a cylinder bore, two inlet bores, two outlet bores and four return bores terminating in said cylinder bore, a twin piston means adjoined by two shifting piston means being retained floatingly in a center position by means of two compression springs and an elastic detent means when the two brake circuit means are operable.

Claim 21

A safety installation for two-circuit brake systems, especially of motor vehicles, in which two brake circuit means independent of one another, of which each brake circuit means includes its own line system and independent wheel brake cylinders, is supplied with pressure fluid by a master brake cylinder means, characterized by a closure means common to both brake circuit means and connected in the Output of the master brake cylinder means, said closure means including control means operable in case of pressure loss in one brake circuit means to automatically close the pressure medium supply into said one inoperable brake circuit means by the pressure which builds up during actuation of the brake system in the other operable brake circuit means, characterized in that the closing means includes a housing provided with a cylinder bore, two inlet bores, two outlet bores and four return bores terminating in said cylinder bore, a twin piston means adjoined by two shifting piston means being retained floatingly in a center position by means of two compression springs and an elastic detent means when the two brake circuit means are operable.

Claim 22

A safety installation according to claim 19, characterized in that in case of pressure loss in a brake circuit means, the operating pressure of the other operable brake circuit means which builds up displaces the twin piston means as well as the shifting piston means.

Claim 23

A safety installation according to claim 20, characterized in that the twin piston means during its displacement forces two detent pin means of the detent means out of a detent groove into the housing and in that a detent pin closes thereat a contact switch actuating a warning lamp.

Claim 24

A safety installation according to claim 21, characterized in that the displaced twin piston means closes off the inoperable brake circuit means and the displaced shifting piston means close off two return lines.

Claim 25

A safety installation according to claim 22, characterized in that the twin piston means as well as the shifting piston means of an inoperable brake circuit means are kept in the closing position by the re-engagement of the detent pins in a further adjacent detent groove of the twin piston means.

Claim 26

A safety installation according to claim 23, characterized in that the shifting piston means of an operable brake circuit means after termination of the braking operation again keeps closed the outlet bore of an operable brake circuit means under the pressure of the coordinated compression spring and again keeps open the return line.

Claim 27

A safety installation for controlling brake fluid flow from a plurality of separately supplied brake fluid input lines to a corresponding plurality of brake fluid output lines which lead respectively to a corresponding plurality of independently actuable wheel brake cylinders at a wheel to be braked; said installation comprising: a control valve housing, first and second separately supplied brake fluid input lines leading into said valve housing, first and second output lines leading out of said valve housing for separately supplying brake fluid pressure to respective first and second independently actuable wheel brake cylinders at a wheel to be braked, control piston means movably disposed in said valve housing and including means for permitting communication of said first input line with said first output line and of said second input line with said second output line when approximately equal brake fluid pressure buildup is experienced in said first and second output lines corresponding to normally functioning respective first and second brake circuits containing said respective first and second output lines, said control piston means including further means for automatically closing off the communication of the respective input and output lines of one of said brake circuits by way of the pressure buildup in the output line of the other brake circuit when said one brake circuit fails with a consequent loss in pressure in the output line thereof, a first return line leading from said valve housing at a position spaced from any of said input and output lines for returning portions of the brake fluid in said first brake circuit from said first output line to a source which supplies said first input line, and a second return line leading from said valve housing at a position spaced from said first return line and any of said input and output lines for returning portions of the brake fluid in said second brake circuit from said second output line to a source which supplies said second input line.

Claim 28

A safety installation for controlling brake fluid flow from a plurality of separately supplied brake fluid input lines to a corresponding plurality of brake fluid output lines which lead respectively to a corresponding plurality of independently actuable wheel brake cylinders at a wheel to be braked; said installation comprising: a control valve housing, first and second separately supplied brake fluid input lines leading into said valve housing, first and second output lines leading out of said valve housing for separately supplying brake fluid pressure to respective first and second independently actuable wheel brake cylinders at a wheel to be braked, control piston means movably disposed in said valve housing and including means for permitting communication of said first input line with said first output line and of said second input line with said second output line when approximately equal brake fluid pressure buildup is experienced in said first and second output lines corresponding to normally functioning respective first and second brake circuits containing said respective first and second output lines, said control piston means including further means for automatically closing off the communication of the respective input and output lines of one of said brake circuits by way of the pressure buildup in the output line of the other brake circuit when said one brake circuit fails with a consequent loss in pressure in the output line thereof, a first return line leading from said valve housing at a position spaced from any of said input and output lines for returning portions of the brake fluid in said first brake circuit from said first output line to a source which supplies said first input line, and a second return line leading from said valve housing at a position spaced from said first return line and any of said input and output lines for returning portions of the brake fluid in said second brake circuit from said second output line to a source which supplies said second input line.

Claim 29

An installation according to claim 26, wherein said control piston means also includes means for automatically closing off the communication between the return line and output line of said brake circuit which fails by way of the pressure buildup in the output line of the other brake circuit.

Claim 30

An installation according to claim 26, wherein said control piston means includes a first central piston slidably mounted in a cylinder bore of said valve housing and second and third end pistons disposed at respective opposite ends of said first piston and slidably guided in said cylinder bore and in said first piston, and wherein said first piston includes first passage means for communicating said first input line with said first output line and second passage means for communicating said second input line with said second output line when said first piston is in a central position corresponding to normal operations with both brake circuits intact.

Claim 31

An installation according to claim 27, wherein said second piston is movable between a first position for blocking communication between said first output line and said first return line and a second position for permitting communication between said first output line and said first return line, said second piston being in said first position when said first brake circuit is inoperative and a pressure buildup occurs at said second output line.

Claim 32

An installation according to claim 28, wherein said third piston is movable between a first position for blocking communication between said second output line and said second return line and a second position for permitting communication between said second output line and said second return line, said third piston being in said first position when said second brake circuit is inoperative and a pressure buildup occurs at said first output line.

Claim 33

An installation according to claim 27, wherein said respective output lines lead radially into said cylinder bore, and wherein peripheral radially outwardly facing surface portions of said first piston close off respective ones of said output lines when said first piston is moved a predetermined amount from said central position upon failure of the brake circuit associated with the output line being closed.

Claim 34

An installation according to claim 29, wherein said respective output lines lead radially into said cylinder bore, and wherein peripheral radially outwardly facing surface portions of said first piston close off respective ones of said output lines when said first piston is moved a predetermined amount from said central position upon failure of the brake circuit associated with the output line being closed.

Claim 35

A safety installation for controlling brake fluid flow from a plurality of separately supplied brake fluid input lines to a corresponding plurality of brake fluid output lines which lead respectively to a corresponding plurality of independently actuable wheel brake cylinders at a wheel to be braked; said installation comprising: a control valve housing, first and second separately supplied brake fluid input lines leading into said valve housing, first and second output lines leading out of said valve housing for separately supplying brake fluid pressure to respective first and second independently actuable wheel brake cylinders at a wheel to be braked, and control piston means movably disposed in said valve housing and including means for permittting communication of said first input line with said first output line and of said second input line with said second output line when approximately equal brake fluid pressure buildup is experienced in said first and second output lines corresponding to normally functioning respective first and second brake circuits containing said respective first anD second output lines, said control piston means including further means for automatically closing off the communication of the respective input and output lines of one of said brake circuits by way of the pressure buildup in the output line of the other brake circuit when said one brake circuit fails with a consequent loss in pressure in the output line thereof, wherein said control piston means includes a first central piston slidably mounted in a cylinder bore of said valve housing, and wherein said first central piston includes first passage means for communicating said first input line with said first output line and second passage means for communicating said second input line with said second output line when said first piston is in a central position corresponding to normal operations with both brake circuits intact.

Claim 36

A safety installation for controlling brake fluid flow from a plurality of separately supplied brake fluid input lines to a corresponding plurality of brake fluid output lines which lead respectively to a corresponding plurality of independently actuable wheel brake cylinders at a wheel to be braked; said installation comprising: a control valve housing, first and second separately supplied brake fluid input lines leading into said valve housing, first and second output lines leading out of said valve housing for separately supplying brake fluid pressure to respective first and second independently actuable wheel brake cylinders at a wheel to be braked, and control piston means movably disposed in said valve housing and including means for permittting communication of said first input line with said first output line and of said second input line with said second output line when approximately equal brake fluid pressure buildup is experienced in said first and second output lines corresponding to normally functioning respective first and second brake circuits containing said respective first anD second output lines, said control piston means including further means for automatically closing off the communication of the respective input and output lines of one of said brake circuits by way of the pressure buildup in the output line of the other brake circuit when said one brake circuit fails with a consequent loss in pressure in the output line thereof, wherein said control piston means includes a first central piston slidably mounted in a cylinder bore of said valve housing, and wherein said first central piston includes first passage means for communicating said first input line with said first output line and second passage means for communicating said second input line with said second output line when said first piston is in a central position corresponding to normal operations with both brake circuits intact.

Claim 37

An installation according to claim 32, wherein said respective output lines lead radially into said cylinder bore, and wherein peripheral radially outwardly facing surface portions of said first piston close off respective ones of said output lines when said first piston is moved a predetermined amount from said central position upon failure of the brake circuit associated wtih the output line being closed.

Claim 38

An installation according to claim 32, wherein said first and second passage means include respective centrally disposed openings extending in the direction of movement of said first piston from respective positions adjacent said inlet lines to respective extreme outer ends of said first piston, said extreme outer ends being adjacent respective ones of said outlet lines when said first piston is in said central position.

Claim 39

A safety installation according to claim 33, characterized in that the first piston is retained in its respective position by a detent means.

Claim 40

A safety installation according to claim 35, characterized in that the detent means includes a contact switch which is actuated by dislacement of the first piston and which indicates the closing off of the inoperable brake circuit means by the closing of an electric circuit mens for a warning device.

Claim 41

A safety installation according to claim 36, characterized in that the contact switch is included in the detent means.