Proportioning device

Claim 2

A brake pressure control device 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 through which fluid is adapted to be displaced to a brake cylinder, and a fluid chamber for providing communication between said inlet and said outlet; means in said chamber movable in response to fluid pressure at said inlet above a first predetermined pressure for decreasing the transmission of fluid pressure from said inlet to said outlet, said means having a first area exposed to fluid pressure at said inlet and a second area greater than said first area exposed to fluid pressure at said outlet, whereby said means is movable toward said inlet in response to a preselected increase in fluid pressure at said inlet, a member in said fluid chamber being adapted for movement in response to a second higher predetermined fluid pressure at said inlet and cooperable with said means in said chamber so as to move in unison therewith to provide a modified movement of said means in response to fluid pressure at said inlet, thereby providing a modified transmission of fluid pressure from said inlet to said outlet.

Claim 3

A brake pressure control device according to claim 1 wherein said member is engageable with said means to provide a substantially constant pressure differential between said inlet and said outlet.

Claim 4

A brake pressure control device according to claim 1 wherein said member is engageable with said means to provide a decreasing pressure differential between said inlet and said outlet.

Claim 5

A brake pressure control device according to claim 1 wherein the ratio of said first and second total areas is established so as to provide movement of said means in response to said fluid pressure at said inlet.

Claim 6

A brake pressure control device according to claim 1 further including a valve member between said inlet and said outlet, and wherein said means has a valve portion cooperating with said valve member to decrease the transmission of fluid pressure from said inlet to said outlet.

Claim 7

A brake pressure control device according to claim 5 wherein said member is adapted for movement away from said inlet in response To a pressure drop across said member and wherein engagement of said member with said means provides a composite structure wherein the differential in said total areas is modified.

Claim 8

A brake pressure control device according to claim 6 wherein said member is provided with a shoulder for abutment with said means to provide movement in unison therewith.

Claim 9

A brake pressure control device according to claim 7 wherein said means and said member are mounted in said housing for reciprocatory movement therein.

Claim 10

A brake pressure control device according to claim 8 wherein one of said means or said member is mounted in journalled relationship with the other.

Claim 11

A brake pressure control device 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 through which which fluid is adapted to be displaced to a brake cylinder, and a fluid chamber for providing communication between said inlet and said outlet; differential area means in said chamber for controlling fluid communication from said inlet to said outlet, said differential area means having a first area exposed to said inlet and a second area larger than said first area exposed to said outlet, whereby said means is adapted for movement in response to preselected fluid pressure for decreasing the transmission of fluid pressure from said inlet to said outlet, resilient means for exerting a force on said differential area means for preventing movement of said differential area means and consequent decreasing of the transmission of fluid pressure thereby below a first predetermined fluid pressure at said inlet, and for yielding to allow movement of said differential area means to decrease the transmission of fluid pressure from said inlet to said outlet above said first predetermined fluid pressure at said inlet, a member in said fluid chamber being adapted for movement in response to fluid pressure at said inlet and cooperable with said differential area means so as to move in unison therewith to provide a modified movement of said means in response to fluid pressure at said inlet; and resilient means for exerting a force on said member for preventing movement of said member which modifies the movement of said differential area means below a second higher predetermined fluid pressure at said inlet and for yielding to allow movement of said differential area means to engage said differential area means above said second predetermined fluid pressure at said inlet to modify said movement of said differential area means.

Claim 12

A brake pressure control device 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 through which which fluid is adapted to be displaced to a brake cylinder, and a fluid chamber for providing communication between said inlet and said outlet; differential area means in said chamber for controlling fluid communication from said inlet to said outlet, said differential area means having a first area exposed to said inlet and a second area larger than said first area exposed to said outlet, whereby said means is adapted for movement in response to preselected fluid pressure for decreasing the transmission of fluid pressure from said inlet to said outlet, resilient means for exerting a force on said differential area means for preventing movement of said differential area means and consequent decreasing of the transmission of fluid pressure thereby below a first predetermined fluid pressure at said inlet, and for yielding to allow movement of said differential area means to decrease the transmission of fluid pressure from said inlet to said outlet above said first predetermined fluid pressure at said inlet, a member in said fluid chamber being adapted for movement in response to fluid pressure at said inlet and cooperable with said differential area means so as to move in unison therewith to provide a modified movement of said means in response to fluid pressure at said inlet; and resilient means for exerting a force on said member for preventing movement of said member which modifies the movement of said differential area means below a second higher predetermined fluid pressure at said inlet and for yielding to allow movement of said differential area means to engage said differential area means above said second predetermined fluid pressure at said inlet to modify said movement of said differential area means.

Claim 13

A brake pressure control device according to claim 10 wherein said member is engageable with said differential area means to provide a substantially constant pressure differential between said inlet and said outlet.

Claim 14

A brake pressure control device according to claim 10 wherein said member is engageable with said differential area means to provide a decreasing pressure differential between said inlet and said outlet.

Claim 15

A brake pressure control device according to claim 10 wherein said differential area means moves toward said inlet in response to said fluid pressure at said fluid inlet.

Claim 16

A brake pressure control device according to claim 13 wherein said member is adapted for movement away from said inlet in response to a pressure drop across said member and wherein engagement of said member with said differential area means provides a composite structure wherein the differential in said total areas is less.

Claim 17

A brake pressure control device according to claim 14 wherein said member is provided with a shoulder for abutment with said differential area means to provide movement in unison therewith.

Claim 18

A brake pressure control device according to claim 15 further including a valve member between said inlet and said outlet, and wherein said differential area means has a valve portion cooperating with said valve member to provide said decrease in Transmission of fluid pressure from said inlet to said outlet.

Claim 19

A brake pressure control device according to claim 16 wherein said differential area means and said member are mounted in said housing for reciprocatory movement therein.

Claim 20

A brake pressure control device according to claim 17 wherein one of said differential area means and said member are mounted in journalled relationship with the other.