Proportioning device

Claim 2

A two stage proportioning valve for use in a vehicle hydraulic brake system comprising: a housing having a fluid inlet adapted to receive fluid from a source of fluid pressure, a fluid outlet adapted for transmission of fluid pressure to a brake cylinder, and a fluid chamber for providing pressure communication between said inlet and said outlet; first means in said chamber having a first valve portion thereon, said means being adapted for movement in response to fluid pressure at said inlet above a first predetermined pressure; a member of said fluid chamber Having a second valve portion thereon cooperating with said first valve portion being adapted for a predetermined movement in response to a second higher predetermined fluid pressure at said inlet. second means supported by said first means for maintaining said second valve portion spaced from said first valve portion at fluid pressure levels below said first predetermined pressure to provide for fluid communication from said inlet to said outlet, movement of said means at said first predetermined pressure causing engagement at said first valve portion with said second valve portion for interrupting the transmission of full fluid pressure from said inlet and said outlet, said movement of said member preventing engagement of said first valve portion with said second valve portion.

Claim 3

A proportioning valve according to claim 1 wherein movement of said member provides a substantially constant offset between said pressure at said inlet and said pressure transmitted to said outlet above said second predetermined fluid pressure at said inlet.

Claim 4

A proportioning valve according to claim 1 wherein said housing has means limiting movement of said means in said first chamber in a direction causing said engagement of said first and second valve portions after engagement of said first and second valve portions and wherein said movement of said member is in said direction whereby engagement of said first and second valve portions is prevented by said housing movement limiting means upon predetermined movement of said member in said direction.

Claim 5

A proportioning valve according to claim 1 wherein said means in said first chamber has a first total area exposed to fluid pressure at said inlet and a second total area exposed to fluid pressure at said outlet, the ratio of said first and second total area being established so as to provide movement of said first means in response to said fluid pressure at said inlet.

Claim 6

A proportioning valve according to claim 4 wherein said second total area is greater than said first total area so that said means moves toward said inlet in response to said fluid pressure at said fluid inlet, and wherein said member is adapted for movement toward said inlet in response to a pressure drop across said member.

Claim 7

A proportioning valve according to claim 1 further including means providing a chamber communicating with said outlet which is contractible in response to pressure increases at said inlet and expansible in response to pressure decreases at said inlet, said chamber provides a pressure reduction at said outlet in response to pressure decrease at said inlet above said second predetermined inlet pressure.

Claim 8

A proportioning valve according to claim 6 wherein said first mentioned means in said chamber includes a bore communicating with said outlet and said chamber and wherein said chamber means is a resilient member on said means in said chamber.

Claim 9

A two stage proportioning valve for use in a vehicle hydraulic brake system comprising: a housing having fluid inlet adapted to receive fluid from a source of fluid pressure, a fluid outlet adapted for transmission of fluid pressure to a brake cylinder, and a fluid chamber for providing communication between said inlet and said outlet; differential area means in said chamber, having a first valve portion thereon, sealingly engaging the walls thereof and providing fluid communication from said inlet to said outlet, said differential area means being adapted for movement in response to fluid pressure at said inlet; resilient means for exerting a force on said differential area means for maintaining said first valve portion in an open condition whereby to provide for fluid communication between said inlet and said outlet at fluid pressure below a first predetermined fluid pressure, said last mentioned means preventing movement of said differential area means below said first predetermined fluid pressure at said inlet and for allowing movement of said differential area Means above said first predetermined fluid pressure at said inlet; a member in said fluid chamber having a second valve portion thereon being adapted for predetermined movement in response to fluid pressure at said inlet; spacer means supported by said differential area means for maintaining said second valve portion in spaced relationship relative to said first valve means below said first predetermined fluid pressure; resilient means for exerting a force on said member for providing said predetermined movement of said member above a second higher predetermined pressure at said inlet; and said movement of said differential area means at said first predetermined pressure causing engagement at said first valve portion with said second valve portion for interrupting the transmission of full fluid pressure from said inlet and said outlet, said movement of said member preventing engagement of said first valve portion with said second valve portion.

Claim 10

A two stage proportioning valve for use in a vehicle hydraulic brake system comprising: a housing having fluid inlet adapted to receive fluid from a source of fluid pressure, a fluid outlet adapted for transmission of fluid pressure to a brake cylinder, and a fluid chamber for providing communication between said inlet and said outlet; differential area means in said chamber, having a first valve portion thereon, sealingly engaging the walls thereof and providing fluid communication from said inlet to said outlet, said differential area means being adapted for movement in response to fluid pressure at said inlet; resilient means for exerting a force on said differential area means for maintaining said first valve portion in an open condition whereby to provide for fluid communication between said inlet and said outlet at fluid pressure below a first predetermined fluid pressure, said last mentioned means preventing movement of said differential area means below said first predetermined fluid pressure at said inlet and for allowing movement of said differential area Means above said first predetermined fluid pressure at said inlet; a member in said fluid chamber having a second valve portion thereon being adapted for predetermined movement in response to fluid pressure at said inlet; spacer means supported by said differential area means for maintaining said second valve portion in spaced relationship relative to said first valve means below said first predetermined fluid pressure; resilient means for exerting a force on said member for providing said predetermined movement of said member above a second higher predetermined pressure at said inlet; and said movement of said differential area means at said first predetermined pressure causing engagement at said first valve portion with said second valve portion for interrupting the transmission of full fluid pressure from said inlet and said outlet, said movement of said member preventing engagement of said first valve portion with said second valve portion.

Claim 11

A proportioning valve according to claim 8 wherein movement of said member provides a substantially constant offset between said pressure at said inlet and said pressure transmitted to said outlet above said second predetermined fluid pressure at said inlet.

Claim 12

A proportioning valve according to claim 9 wherein said housing has differential area means limiting movement of said differential area means in said chamber in a direction causing said engagement of said first and second valve portions after engagement of said first and second valve portions and wherein said movement of said member is in said direction whereby engagement of said first and second valve portions is prevented by said housing movement limiting differential area means upon predetermined movement of said member in said direction.

Claim 13

A proportioning valve according to claim 8 wherein said differential area means in said chamber has a first total area exposed to fluid pressure at said inlet and a second total area exposed to fluid pressure at said outlet, the ratio of said first and second total areas being established so as to provide movement of said means in response to said fluid pressure at said inlet.

Claim 14

A proportioning valve according to claim 11 wherein said second total area is greater than said first total area so that said means moves toward said inlet in response to said fluid pressure at said fluid inlet.

Claim 15

A proportioning valve according to claim 12 wherein said member is adapted for movement toward said inlet in response to a pressure drop across said member.

Claim 16

A proportioning valve according to claim 8 further including means providing a chamber communicating with said outlet which is contractible in response to pressure increases at said inlet and expansible in response to pressure decreases at said inlet, said chamber providing a pressure reduction at said outlet in response to pressure decrease at said inlet above said second predetermined inlet pressure.

Claim 17

A proportioning valve according to claim 14 wherein said first differential area means in said chamber includes a bore communicating with said outlet and said chamber and wherein said chamber means is a resilient member on said means in said chamber.

Claim 18

A two stage proportioning valve for use in a vehicle hydraulic brake system comprising: a housing having fluid inlet adapted to receive fluid from a source of fluid pressure, a fluid outlet adapted for transmission of fluid pressure to a brake cylinder, and a fluid chamber for providing communication between said inlet and said outlet; differential area means in said chamber, having a first valve portion thereon, sealingly engaging the walls thereof and including a passage providing fluid communication from said inlet to said outlet, said differential area means being adapted for movement in response to fluid pressure at said inlet; said differential area means in said chamber having a first total area exposed to fluid pressure at said inlet and a second total area expoSed to fluid pressure at said outlet, the ratio of said first and second total areas being established so as to provide movement of said means in response to said fluid pressure at said inlet, said second total area being greater than said first total area so that said means moves toward said inlet in response to said fluid pressure at said fluid inlet, resilient means for exerting a force on said differential area means for maintaining said first valve portion in an open condition whereby to provide for fluid communication between said inlet and said outlet at fluid pressure below a first predetermined fluid pressure, said last mentioned means preventing movement of said differential area means below said first predetermined fluid pressure at said inlet and for allowing movement of said differential area means above said first predetermined fluid pressure at said inlet; a member in said fluid chamber having a second valve portion thereon being adapted for a predetermined movement in response to fluid pressure at said inlet; resilient means for exerting a force on said member for providing said predetermined movement of said member above a second higher predetermined pressure at said inlet; spacer means located in said passage of said differential area means for maintaining said second valve portion in spaced relationship relative to said first valve means below said first predetermined fluid pressure; said movement of said differential area means at said first predetermined pressure causing engagement at said first valve portion with said second valve portion for interrupting the transmission of full fluid pressure from said inlet and said outlet, movement of said member provides a substantially constant offset between said pressure at said inlet and said pressure transmitted to said outlet above said second predetermined fluid pressure at said inlet, with said movement of said member preventing engagement of said first valve portion with said second valve portion, said housing having differential area means limiting movement of said differential area means in said chamber in a direction causing said engagement of said first and second valve portions after engagement of said first and second valve portions and wherein said movement of said member is in said direction whereby engagement of said first and second valve portions is prevented by said housing movement limiting differential area means upon predetermined movement of said member in said direction.

Claim 19

A two stage proportioning valve for use in a vehicle hydraulic brake system comprising: a housing having fluid inlet adapted to receive fluid from a source of fluid pressure, a fluid outlet adapted for transmission of fluid pressure to a brake cylinder, and a fluid chamber for providing communication between said inlet and said outlet; differential area means in said chamber, having a first valve portion thereon, sealingly engaging the walls thereof and including a passage providing fluid communication from said inlet to said outlet, said differential area means being adapted for movement in response to fluid pressure at said inlet; said differential area means in said chamber having a first total area exposed to fluid pressure at said inlet and a second total area expoSed to fluid pressure at said outlet, the ratio of said first and second total areas being established so as to provide movement of said means in response to said fluid pressure at said inlet, said second total area being greater than said first total area so that said means moves toward said inlet in response to said fluid pressure at said fluid inlet, resilient means for exerting a force on said differential area means for maintaining said first valve portion in an open condition whereby to provide for fluid communication between said inlet and said outlet at fluid pressure below a first predetermined fluid pressure, said last mentioned means preventing movement of said differential area means below said first predetermined fluid pressure at said inlet and for allowing movement of said differential area means above said first predetermined fluid pressure at said inlet; a member in said fluid chamber having a second valve portion thereon being adapted for a predetermined movement in response to fluid pressure at said inlet; resilient means for exerting a force on said member for providing said predetermined movement of said member above a second higher predetermined pressure at said inlet; spacer means located in said passage of said differential area means for maintaining said second valve portion in spaced relationship relative to said first valve means below said first predetermined fluid pressure; said movement of said differential area means at said first predetermined pressure causing engagement at said first valve portion with said second valve portion for interrupting the transmission of full fluid pressure from said inlet and said outlet, movement of said member provides a substantially constant offset between said pressure at said inlet and said pressure transmitted to said outlet above said second predetermined fluid pressure at said inlet, with said movement of said member preventing engagement of said first valve portion with said second valve portion, said housing having differential area means limiting movement of said differential area means in said chamber in a direction causing said engagement of said first and second valve portions after engagement of said first and second valve portions and wherein said movement of said member is in said direction whereby engagement of said first and second valve portions is prevented by said housing movement limiting differential area means upon predetermined movement of said member in said direction.

Claim 20

The invention as set forth in claim 16 which includes means providing a chamber communicating with said outlet which is contractible in response to pressure increases at said inlet and including a resilient member expansible in response to pressure decreases at said inlet, said chamber providing a pressure reduction at said outlet in response to pressure decrease at said inlet above said second predetermined inlet pressure.

Claim 21

A two stage proportioning valve for a vehicle hydraulic brake system to modulate the brake pressure to the rear brakes comprising: a housing having an inlet port adapted to receive fluid from a source of fluid pressure, an outlet port adapted for transmission of fluid pressure to the rear brake cylinders, and a fluid chamber for providing communication between said inlet and outlet ports, said chamber including first and second spaced cylindrical passages at opposite ends thereof; a piston having an end portion supported for reciprocal movement in one of said passages and an opposite end defining a first valve portion, said piston including a bore between said end portions, a spacer member located in the bore of said piston and dimensioned to extend outwardly therefrom, a cap member having an internal passage and slidably located in the other of said passages; a composite member having a second valve portion cooperable with said first valve portion and slidably located in said internal passage of said cap member, said second valve portion bEing spaced from said first valve portion via abutment with said spacer member during a first predetermined fluid pressure at said inlet; first spring means interposed between said piston and said cap member for locating said first valve portion in spaced relationship relative to said second valve portion at fluid pressures at said inlet below said first predetermined level and responsive to said first predetermined pressure to bias said first valve portion toward said second valve portion; second spring means located in said internal passage of said cap member for urging said second valve portion against said spacer member and responsive to a second higher predetermined pressure level at said inlet to bias said second valve portion away from said first valve portion.

Claim 22

A two stage proportioning valve for a vehicle hydraulic brake system to modulate the brake pressure to the rear brakes comprising: a housing having an inlet port adapted to receive fluid from a source of fluid pressure, an outlet port adapted for transmission of fluid pressure to the rear brake cylinders, and a fluid chamber for providing communication between said inlet and outlet ports, said chamber including first and second spaced cylindrical passages at opposite ends thereof; a piston having an end portion supported for reciprocal movement in one of said passages and an opposite end defining a first valve portion, said piston including a bore between said end portions, a spacer member located in the bore of said piston and dimensioned to extend outwardly therefrom, a cap member having an internal passage and slidably located in the other of said passages; a composite member having a second valve portion cooperable with said first valve portion and slidably located in said internal passage of said cap member, said second valve portion bEing spaced from said first valve portion via abutment with said spacer member during a first predetermined fluid pressure at said inlet; first spring means interposed between said piston and said cap member for locating said first valve portion in spaced relationship relative to said second valve portion at fluid pressures at said inlet below said first predetermined level and responsive to said first predetermined pressure to bias said first valve portion toward said second valve portion; second spring means located in said internal passage of said cap member for urging said second valve portion against said spacer member and responsive to a second higher predetermined pressure level at said inlet to bias said second valve portion away from said first valve portion.